From a3bf0f28d4ba16e1f35f8c983bb04426b87e2a78 Mon Sep 17 00:00:00 2001 From: Junyoung Jang Date: Mon, 4 May 2026 20:26:49 +0900 Subject: fs/statmount: fix slab out-of-bounds write in statmount_mnt_idmap statmount_mnt_idmap() writes one mapping with seq_printf() and then manually advances seq->count to include the NUL separator. If seq_printf() overflows, seq_set_overflow() sets seq->count to seq->size. The manual seq->count++ changes this to seq->size + 1. seq_has_overflowed() then no longer detects the overflow. The corrupted count returns to statmount_string(), which later executes: seq->buf[seq->count++] = '\0'; This causes a 1-byte NULL out-of-bounds write on the dynamically allocated seq buffer. Fix this by checking for overflow immediately after seq_printf(). Fixes: 37c4a9590e1e ("statmount: allow to retrieve idmappings") Signed-off-by: Junyoung Jang Link: https://patch.msgid.link/20260504112649.1862936-1-graypanda.inzag@gmail.com Signed-off-by: Christian Brauner --- fs/mnt_idmapping.c | 2 ++ 1 file changed, 2 insertions(+) diff --git a/fs/mnt_idmapping.c b/fs/mnt_idmapping.c index 6472c4ea3d1e..cb61fbdb52e9 100644 --- a/fs/mnt_idmapping.c +++ b/fs/mnt_idmapping.c @@ -375,6 +375,8 @@ int statmount_mnt_idmap(struct mnt_idmap *idmap, struct seq_file *seq, bool uid_ continue; seq_printf(seq, "%u %u %u", extent->first, lower, extent->count); + if (seq_has_overflowed(seq)) + return -EAGAIN; seq->count++; /* mappings are separated by \0 */ if (seq_has_overflowed(seq)) -- cgit v1.2.3 From a7cf1da7ac016490d6a1106f2aa6b602d34e9a12 Mon Sep 17 00:00:00 2001 From: Hongling Zeng Date: Fri, 1 May 2026 15:10:58 +0800 Subject: fs: Fix return in jfs_mkdir and orangefs_mkdir Return NULL instead of passing to ERR_PTR while err is zero Fixes these smatch warnings: - fs/jfs/namei.c:311 jfs_mkdir() warn: passing zero to 'ERR_PTR' - fs/orangefs/namei.c:369 orangefs_mkdir() warn: passing zero to 'ERR_PTR' Fixes: 88d5baf69082 ("Change inode_operations.mkdir to return struct dentry *") Signed-off-by: Hongling Zeng Link: https://patch.msgid.link/20260501071058.1243245-1-zenghongling@kylinos.cn Reviewed-by: Jori Koolstra Signed-off-by: Christian Brauner --- fs/jfs/namei.c | 2 +- fs/orangefs/namei.c | 2 +- 2 files changed, 2 insertions(+), 2 deletions(-) diff --git a/fs/jfs/namei.c b/fs/jfs/namei.c index 60c4a0e0fca5..442d62679262 100644 --- a/fs/jfs/namei.c +++ b/fs/jfs/namei.c @@ -309,7 +309,7 @@ static struct dentry *jfs_mkdir(struct mnt_idmap *idmap, struct inode *dip, out1: jfs_info("jfs_mkdir: rc:%d", rc); - return ERR_PTR(rc); + return rc ? ERR_PTR(rc) : NULL; } /* diff --git a/fs/orangefs/namei.c b/fs/orangefs/namei.c index bec5475de094..75e65e72c2d6 100644 --- a/fs/orangefs/namei.c +++ b/fs/orangefs/namei.c @@ -362,7 +362,7 @@ static struct dentry *orangefs_mkdir(struct mnt_idmap *idmap, struct inode *dir, __orangefs_setattr(dir, &iattr); out: op_release(new_op); - return ERR_PTR(ret); + return ret ? ERR_PTR(ret) : NULL; } static int orangefs_rename(struct mnt_idmap *idmap, -- cgit v1.2.3 From c3880a7b10e487e033dc6f388bda118436566f7a Mon Sep 17 00:00:00 2001 From: Junxi Qian Date: Wed, 6 May 2026 20:24:15 +0800 Subject: fuse: fix writeback array overflow when max_pages is one fuse_iomap_writeback_range() appends one folio pointer and one fuse_folio_desc for every dirty range that is merged into the current writeback request. The merge decision checks the byte budget against fc->max_pages and fc->max_write, but it does not check whether the folio and descriptor arrays still have another free slot. This is not sufficient for fuseblk, where the filesystem block size can be smaller than PAGE_SIZE. With writeback cache enabled and max_pages negotiated as one, contiguous sub-page dirty ranges can fit within the byte budget while spanning more than one folio. The next append can then write past the one-slot folios and descs arrays. Split the request when the number of already attached folios has reached fc->max_pages. This keeps the folio/descriptor slot accounting in sync with the send decision. Fixes: ef7e7cbb323f ("fuse: use iomap for writeback") Cc: stable@vger.kernel.org Reviewed-by: Joanne Koong Signed-off-by: Junxi Qian Link: https://patch.msgid.link/20260506122415.205340-1-qjx1298677004@gmail.com Acked-by: Miklos Szeredi Signed-off-by: Christian Brauner --- fs/fuse/file.c | 5 ++++- 1 file changed, 4 insertions(+), 1 deletion(-) diff --git a/fs/fuse/file.c b/fs/fuse/file.c index c59452d60b8d..f94f3dc082c6 100644 --- a/fs/fuse/file.c +++ b/fs/fuse/file.c @@ -2176,7 +2176,10 @@ static bool fuse_folios_need_send(struct fuse_conn *fc, loff_t pos, WARN_ON(!ap->num_folios); - /* Reached max pages */ + /* Reached max pages or max folio slots */ + if (ap->num_folios >= fc->max_pages) + return true; + if (DIV_ROUND_UP(bytes, PAGE_SIZE) > fc->max_pages) return true; -- cgit v1.2.3 From 834e98acb748025c04fed3cac9c8954454f4b520 Mon Sep 17 00:00:00 2001 From: Pankaj Raghav Date: Mon, 11 May 2026 13:19:18 +0200 Subject: fs: fix forced iversion increment on lazytime timestamp updates When updating timestamps with lazytime enabled, if only I_DIRTY_TIME is set (pure lazytime update), inode_maybe_inc_iversion() should not be forced to increment i_version. The force parameter should only be true when actual data or metadata changes require an iversion bump. The current code uses "!!dirty" which evaluates to true whenever dirty has any bits set, including the I_DIRTY_TIME bit alone. This forces an iversion increment on every lazytime timestamp update, which then sets I_DIRTY_SYNC, triggering expensive log flushes on subsequent fdatasync calls. Andres reported this issue when he noticed a perf regression[1]. Fix this by using "dirty != I_DIRTY_TIME" as the force parameter. This passes false for pure lazytime updates (allowing the I_VERSION_QUERIED optimization to work), while still forcing the increment when dirty contains other flags indicating real changes that require iversion updates. [1] https://lore.kernel.org/linux-xfs/7ys6erh3nnyeerv2nybyfvp7dmaknuxrlxv74wx56ocdothkc6@ekfiadtkfn2r/ Fixes: 85c871a02b03 ("fs: add support for non-blocking timestamp updates") Signed-off-by: Pankaj Raghav Link: https://patch.msgid.link/20260511111918.1793689-1-p.raghav@samsung.com Reviewed-by: Jeff Layton Reviewed-by: Christoph Hellwig Reviewed-by: Carlos Maiolino Signed-off-by: Christian Brauner --- fs/inode.c | 8 +++++++- 1 file changed, 7 insertions(+), 1 deletion(-) diff --git a/fs/inode.c b/fs/inode.c index 6a3cbc7dcd28..62c579a0cf7d 100644 --- a/fs/inode.c +++ b/fs/inode.c @@ -2124,7 +2124,13 @@ static int inode_update_cmtime(struct inode *inode, unsigned int flags) inode_iversion_need_inc(inode)) return -EAGAIN; } else { - if (inode_maybe_inc_iversion(inode, !!dirty)) + /* + * Don't force iversion increment for pure lazytime + * updates (I_DIRTY_TIME only), let I_VERSION_QUERIED + * dictate whether the increment is needed. + */ + if (inode_maybe_inc_iversion(inode, + dirty != I_DIRTY_TIME)) dirty |= I_DIRTY_SYNC; } } -- cgit v1.2.3 From 725ecd80688bf3c57ca9205431f2c06174ff0756 Mon Sep 17 00:00:00 2001 From: Zhihao Cheng Date: Thu, 7 May 2026 19:23:01 +0800 Subject: nsfs: fix wrong error code returned for pidns ioctls When executing NS_GET_PID_FROM_PIDNS (or similar pidns ioctls), if the target task cannot be found in the corresponding pid_ns, the error code should be ESRCH instead of ENOTTY. This bug was introduced when the extensible ioctl handling was added. Without proper return, ret would be overwritten by the default case in the extensible ioctl switch statement. Fixes: a1d220d9dafa8 ("nsfs: iterate through mount namespaces") Signed-off-by: Zhihao Cheng Link: https://patch.msgid.link/20260507112301.1042757-1-chengzhihao1@huawei.com Reviewed-by: Yang Erkun Signed-off-by: Christian Brauner --- fs/nsfs.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/fs/nsfs.c b/fs/nsfs.c index 51e8c9430477..160018c4fb36 100644 --- a/fs/nsfs.c +++ b/fs/nsfs.c @@ -266,7 +266,7 @@ static long ns_ioctl(struct file *filp, unsigned int ioctl, else tsk = find_task_by_pid_ns(arg, pid_ns); if (!tsk) - break; + return ret; switch (ioctl) { case NS_GET_PID_FROM_PIDNS: -- cgit v1.2.3 From 859c199bb3a90ec49a678cc0846694b06703bdde Mon Sep 17 00:00:00 2001 From: Breno Leitao Date: Wed, 29 Apr 2026 06:09:37 -0700 Subject: fs/select: reject negative timeval components in kern_select() kern_select() normalises the user-supplied struct __kernel_old_timeval with tv.tv_sec + (tv.tv_usec / USEC_PER_SEC) (tv.tv_usec % USEC_PER_SEC) * NSEC_PER_USEC before calling poll_select_set_timeout() -> timespec64_valid(). Both operands of the seconds sum are unbounded user-controlled signed long. A crafted pair where tv_usec is a negative multiple of USEC_PER_SEC drives the sum across the wrap boundary - e.g. { .tv_sec = LONG_MIN, .tv_usec = -1000000 } yields sec = LONG_MAX, nsec = 0, which passes timespec64_valid() and then flows through timespec64_add_safe(), which saturates the absolute deadline to TIME64_MAX (clamped further to KTIME_MAX downstream). select(2) therefore blocks effectively forever instead of returning -EINVAL as POSIX requires for a negative timeout. Only the legacy __NR_select syscall takes this path. pselect6, ppoll, poll and epoll_pwait2 all hand the user's two fields directly to poll_select_set_timeout(), which validates *before* doing any arithmetic: /* fs/select.c:271 -- the validator */ int poll_select_set_timeout(struct timespec64 *to, time64_t sec, long nsec) { struct timespec64 ts = {.tv_sec = sec, .tv_nsec = nsec}; if (!timespec64_valid(&ts)) return -EINVAL; ... } /* include/linux/time64.h:97 -- timespec64_valid */ if (ts->tv_sec < 0) return false; if ((unsigned long)ts->tv_nsec >= NSEC_PER_SEC) return false; /* fs/select.c:744 do_pselect() (pselect6, pselect6_time32) */ if (get_timespec64(&ts, tsp)) return -EFAULT; if (poll_select_set_timeout(to, ts.tv_sec, ts.tv_nsec)) return -EINVAL; /* fs/select.c:1097 ppoll */ if (get_timespec64(&ts, tsp)) return -EFAULT; if (poll_select_set_timeout(to, ts.tv_sec, ts.tv_nsec)) return -EINVAL; /* fs/select.c:1065 poll -- timeout_msecs is int; >= 0 gates the math */ if (timeout_msecs >= 0) poll_select_set_timeout(to, timeout_msecs / MSEC_PER_SEC, NSEC_PER_MSEC * (timeout_msecs % MSEC_PER_SEC)); /* fs/eventpoll.c:2512 epoll_pwait2 */ if (get_timespec64(&ts, timeout)) return -EFAULT; if (poll_select_set_timeout(to, ts.tv_sec, ts.tv_nsec)) return -EINVAL; In every one of these the wrap-prone arithmetic from kern_select() simply does not exist; the user fields reach timespec64_valid() unmodified. glibc routes the C-library select() through pselect6, so the bug is reachable only via a direct syscall(__NR_select, ...). The pre-validation negative check that used to live here was lost when the syscall was switched to the poll_select_set_timeout() helper. Restore it: reject tv_sec < 0 || tv_usec < 0 up front, mirroring what glibc does in userspace. do_compat_select() has the same arithmetic pattern but is only reachable on 32-bit compat and from a different syscall entry; left for a follow-up so this change stays minimal. Reproducer (returns -1/EINVAL on a fixed kernel; blocks indefinitely on an unfixed one): struct timeval tv = { .tv_sec = LONG_MIN, .tv_usec = -1000000 }; fd_set r; int pfd[2]; pipe(pfd); FD_ZERO(&r); FD_SET(pfd[0], &r); syscall(__NR_select, pfd[0] + 1, &r, NULL, NULL, &tv); Fixes: 4d36a9e65d49 ("select: deal with math overflow from borderline valid userland data") Signed-off-by: Breno Leitao Link: https://patch.msgid.link/20260429-timeval-v1-1-4448e2588bbf@debian.org Reviewed-by: Jan Kara Signed-off-by: Christian Brauner --- fs/select.c | 11 +++++++++++ 1 file changed, 11 insertions(+) diff --git a/fs/select.c b/fs/select.c index 75978b18f48f..bf71c9838dfe 100644 --- a/fs/select.c +++ b/fs/select.c @@ -708,6 +708,17 @@ static int kern_select(int n, fd_set __user *inp, fd_set __user *outp, if (copy_from_user(&tv, tvp, sizeof(tv))) return -EFAULT; + /* + * Reject negative components before normalisation. The seconds + * sum below is performed in signed long and a crafted negative + * timeval can wrap to a positive value that passes + * timespec64_valid() and turns into an effectively-infinite + * deadline via timespec64_add_safe()'s saturation, instead of + * the -EINVAL POSIX requires for negative timeouts. + */ + if (tv.tv_sec < 0 || tv.tv_usec < 0) + return -EINVAL; + to = &end_time; if (poll_select_set_timeout(to, tv.tv_sec + (tv.tv_usec / USEC_PER_SEC), -- cgit v1.2.3 From 6f0f7ac1915abc0d202f0eb4b003a6548a5ba60d Mon Sep 17 00:00:00 2001 From: David Howells Date: Tue, 12 May 2026 13:33:38 +0100 Subject: netfs: Fix cancellation of a DIO and single read subrequests When the preparation of a new subrequest for a read fails, if the subrequest has already been added to the stream->subrequests list, it can't simply be put and abandoned as the collector may see it. Also, if it hasn't been queued yet, it has two outstanding refs that both need to be put. Both DIO read and single-read dispatch fail at this; further, both differ in the order they do things to the way buffered read works. Fix cancellation of both DIO-read and single-read subrequests that failed preparation by the following steps: (1) Harmonise all three reads (buffered, dio, single) to queue the subreq before prepping it. (2) Make all three call netfs_queue_read() to do the queuing. (3) Set NETFS_RREQ_ALL_QUEUED independently of the queuing as we don't know the length of the subreq at this point. (4) In all cases, set the error and NETFS_SREQ_FAILED flag on the subreq and then call netfs_read_subreq_terminated() to deal with it. This will pass responsibility off to the collector for dealing with it. Fixes: e2d46f2ec332 ("netfs: Change the read result collector to only use one work item") Closes: https://sashiko.dev/#/patchset/20260425125426.3855807-1-dhowells%40redhat.com Signed-off-by: David Howells Link: https://patch.msgid.link/20260512123404.719402-2-dhowells@redhat.com cc: Paulo Alcantara cc: netfs@lists.linux.dev cc: linux-fsdevel@vger.kernel.org Signed-off-by: Christian Brauner --- fs/netfs/buffered_read.c | 34 +++++++++++++--------------------- fs/netfs/direct_read.c | 42 +++++++++++++----------------------------- fs/netfs/internal.h | 3 +++ fs/netfs/read_collect.c | 11 +++++++++++ fs/netfs/read_single.c | 23 ++++++++++------------- 5 files changed, 50 insertions(+), 63 deletions(-) diff --git a/fs/netfs/buffered_read.c b/fs/netfs/buffered_read.c index a8c0d86118c5..a27ed501b6d4 100644 --- a/fs/netfs/buffered_read.c +++ b/fs/netfs/buffered_read.c @@ -156,9 +156,8 @@ static void netfs_read_cache_to_pagecache(struct netfs_io_request *rreq, netfs_cache_read_terminated, subreq); } -static void netfs_queue_read(struct netfs_io_request *rreq, - struct netfs_io_subrequest *subreq, - bool last_subreq) +void netfs_queue_read(struct netfs_io_request *rreq, + struct netfs_io_subrequest *subreq) { struct netfs_io_stream *stream = &rreq->io_streams[0]; @@ -178,11 +177,6 @@ static void netfs_queue_read(struct netfs_io_request *rreq, } } - if (last_subreq) { - smp_wmb(); /* Write lists before ALL_QUEUED. */ - set_bit(NETFS_RREQ_ALL_QUEUED, &rreq->flags); - } - spin_unlock(&rreq->lock); } @@ -233,6 +227,8 @@ static void netfs_read_to_pagecache(struct netfs_io_request *rreq, subreq->start = start; subreq->len = size; + netfs_queue_read(rreq, subreq); + source = netfs_cache_prepare_read(rreq, subreq, rreq->i_size); subreq->source = source; if (source == NETFS_DOWNLOAD_FROM_SERVER) { @@ -253,6 +249,7 @@ static void netfs_read_to_pagecache(struct netfs_io_request *rreq, rreq->debug_id, subreq->debug_index, subreq->len, size, subreq->start, ictx->zero_point, rreq->i_size); + netfs_cancel_read(subreq, ret); break; } subreq->len = len; @@ -261,12 +258,7 @@ static void netfs_read_to_pagecache(struct netfs_io_request *rreq, if (rreq->netfs_ops->prepare_read) { ret = rreq->netfs_ops->prepare_read(subreq); if (ret < 0) { - subreq->error = ret; - /* Not queued - release both refs. */ - netfs_put_subrequest(subreq, - netfs_sreq_trace_put_cancel); - netfs_put_subrequest(subreq, - netfs_sreq_trace_put_cancel); + netfs_cancel_read(subreq, ret); break; } trace_netfs_sreq(subreq, netfs_sreq_trace_prepare); @@ -289,23 +281,23 @@ static void netfs_read_to_pagecache(struct netfs_io_request *rreq, pr_err("Unexpected read source %u\n", source); WARN_ON_ONCE(1); + netfs_cancel_read(subreq, ret); break; issue: slice = netfs_prepare_read_iterator(subreq, ractl); if (slice < 0) { ret = slice; - subreq->error = ret; - trace_netfs_sreq(subreq, netfs_sreq_trace_cancel); - /* Not queued - release both refs. */ - netfs_put_subrequest(subreq, netfs_sreq_trace_put_cancel); - netfs_put_subrequest(subreq, netfs_sreq_trace_put_cancel); + netfs_cancel_read(subreq, ret); break; } - size -= slice; start += slice; + size -= slice; + if (size <= 0) { + smp_wmb(); /* Write lists before ALL_QUEUED. */ + set_bit(NETFS_RREQ_ALL_QUEUED, &rreq->flags); + } - netfs_queue_read(rreq, subreq, size <= 0); netfs_issue_read(rreq, subreq); cond_resched(); } while (size > 0); diff --git a/fs/netfs/direct_read.c b/fs/netfs/direct_read.c index f72e6da88cca..6a8fb0d55e04 100644 --- a/fs/netfs/direct_read.c +++ b/fs/netfs/direct_read.c @@ -45,12 +45,11 @@ static void netfs_prepare_dio_read_iterator(struct netfs_io_subrequest *subreq) * Perform a read to a buffer from the server, slicing up the region to be read * according to the network rsize. */ -static int netfs_dispatch_unbuffered_reads(struct netfs_io_request *rreq) +static void netfs_dispatch_unbuffered_reads(struct netfs_io_request *rreq) { - struct netfs_io_stream *stream = &rreq->io_streams[0]; unsigned long long start = rreq->start; ssize_t size = rreq->len; - int ret = 0; + int ret; do { struct netfs_io_subrequest *subreq; @@ -58,7 +57,10 @@ static int netfs_dispatch_unbuffered_reads(struct netfs_io_request *rreq) subreq = netfs_alloc_subrequest(rreq); if (!subreq) { - ret = -ENOMEM; + /* Stash the error in the request if there's not + * already an error set. + */ + cmpxchg(&rreq->error, 0, -ENOMEM); break; } @@ -66,25 +68,13 @@ static int netfs_dispatch_unbuffered_reads(struct netfs_io_request *rreq) subreq->start = start; subreq->len = size; - __set_bit(NETFS_SREQ_IN_PROGRESS, &subreq->flags); - - spin_lock(&rreq->lock); - list_add_tail(&subreq->rreq_link, &stream->subrequests); - if (list_is_first(&subreq->rreq_link, &stream->subrequests)) { - if (!stream->active) { - stream->collected_to = subreq->start; - /* Store list pointers before active flag */ - smp_store_release(&stream->active, true); - } - } - trace_netfs_sreq(subreq, netfs_sreq_trace_added); - spin_unlock(&rreq->lock); + netfs_queue_read(rreq, subreq); netfs_stat(&netfs_n_rh_download); if (rreq->netfs_ops->prepare_read) { ret = rreq->netfs_ops->prepare_read(subreq); if (ret < 0) { - netfs_put_subrequest(subreq, netfs_sreq_trace_put_cancel); + netfs_cancel_read(subreq, ret); break; } } @@ -113,8 +103,6 @@ static int netfs_dispatch_unbuffered_reads(struct netfs_io_request *rreq) set_bit(NETFS_RREQ_ALL_QUEUED, &rreq->flags); netfs_wake_collector(rreq); } - - return ret; } /* @@ -137,21 +125,17 @@ static ssize_t netfs_unbuffered_read(struct netfs_io_request *rreq, bool sync) // TODO: Use bounce buffer if requested inode_dio_begin(rreq->inode); + netfs_dispatch_unbuffered_reads(rreq); - ret = netfs_dispatch_unbuffered_reads(rreq); - - if (!rreq->submitted) { - netfs_put_request(rreq, netfs_rreq_trace_put_no_submit); - inode_dio_end(rreq->inode); - ret = 0; - goto out; - } + /* The collector will get run, even if we don't manage to submit any + * subreqs, so we shouldn't call inode_dio_end() here. + */ if (sync) ret = netfs_wait_for_read(rreq); else ret = -EIOCBQUEUED; -out: + _leave(" = %zd", ret); return ret; } diff --git a/fs/netfs/internal.h b/fs/netfs/internal.h index d436e20d3418..645996ecfc80 100644 --- a/fs/netfs/internal.h +++ b/fs/netfs/internal.h @@ -23,6 +23,8 @@ /* * buffered_read.c */ +void netfs_queue_read(struct netfs_io_request *rreq, + struct netfs_io_subrequest *subreq); void netfs_cache_read_terminated(void *priv, ssize_t transferred_or_error); int netfs_prefetch_for_write(struct file *file, struct folio *folio, size_t offset, size_t len); @@ -108,6 +110,7 @@ static inline void netfs_see_subrequest(struct netfs_io_subrequest *subreq, */ bool netfs_read_collection(struct netfs_io_request *rreq); void netfs_read_collection_worker(struct work_struct *work); +void netfs_cancel_read(struct netfs_io_subrequest *subreq, int error); void netfs_cache_read_terminated(void *priv, ssize_t transferred_or_error); /* diff --git a/fs/netfs/read_collect.c b/fs/netfs/read_collect.c index e5f6665b3341..d2d902f46627 100644 --- a/fs/netfs/read_collect.c +++ b/fs/netfs/read_collect.c @@ -575,6 +575,17 @@ skip_error_checks: } EXPORT_SYMBOL(netfs_read_subreq_terminated); +/* + * Cancel a read subrequest due to preparation failure. + */ +void netfs_cancel_read(struct netfs_io_subrequest *subreq, int error) +{ + trace_netfs_sreq(subreq, netfs_sreq_trace_cancel); + subreq->error = error; + __set_bit(NETFS_SREQ_FAILED, &subreq->flags); + netfs_read_subreq_terminated(subreq); +} + /* * Handle termination of a read from the cache. */ diff --git a/fs/netfs/read_single.c b/fs/netfs/read_single.c index d0e23bc42445..8833550d2eb6 100644 --- a/fs/netfs/read_single.c +++ b/fs/netfs/read_single.c @@ -89,7 +89,6 @@ static void netfs_single_read_cache(struct netfs_io_request *rreq, */ static int netfs_single_dispatch_read(struct netfs_io_request *rreq) { - struct netfs_io_stream *stream = &rreq->io_streams[0]; struct netfs_io_subrequest *subreq; int ret = 0; @@ -102,14 +101,7 @@ static int netfs_single_dispatch_read(struct netfs_io_request *rreq) subreq->len = rreq->len; subreq->io_iter = rreq->buffer.iter; - __set_bit(NETFS_SREQ_IN_PROGRESS, &subreq->flags); - - spin_lock(&rreq->lock); - list_add_tail(&subreq->rreq_link, &stream->subrequests); - trace_netfs_sreq(subreq, netfs_sreq_trace_added); - /* Store list pointers before active flag */ - smp_store_release(&stream->active, true); - spin_unlock(&rreq->lock); + netfs_queue_read(rreq, subreq); netfs_single_cache_prepare_read(rreq, subreq); switch (subreq->source) { @@ -121,10 +113,14 @@ static int netfs_single_dispatch_read(struct netfs_io_request *rreq) goto cancel; } + smp_wmb(); /* Write lists before ALL_QUEUED. */ + set_bit(NETFS_RREQ_ALL_QUEUED, &rreq->flags); rreq->netfs_ops->issue_read(subreq); rreq->submitted += subreq->len; break; case NETFS_READ_FROM_CACHE: + smp_wmb(); /* Write lists before ALL_QUEUED. */ + set_bit(NETFS_RREQ_ALL_QUEUED, &rreq->flags); trace_netfs_sreq(subreq, netfs_sreq_trace_submit); netfs_single_read_cache(rreq, subreq); rreq->submitted += subreq->len; @@ -134,14 +130,15 @@ static int netfs_single_dispatch_read(struct netfs_io_request *rreq) pr_warn("Unexpected single-read source %u\n", subreq->source); WARN_ON_ONCE(true); ret = -EIO; - break; + goto cancel; } - smp_wmb(); /* Write lists before ALL_QUEUED. */ - set_bit(NETFS_RREQ_ALL_QUEUED, &rreq->flags); return ret; cancel: - netfs_put_subrequest(subreq, netfs_sreq_trace_put_cancel); + netfs_cancel_read(subreq, ret); + smp_wmb(); /* Write lists before ALL_QUEUED. */ + set_bit(NETFS_RREQ_ALL_QUEUED, &rreq->flags); + netfs_wake_collector(rreq); return ret; } -- cgit v1.2.3 From cce18c263e9623872327ba3c956012f73c1179cc Mon Sep 17 00:00:00 2001 From: David Howells Date: Tue, 12 May 2026 13:33:39 +0100 Subject: netfs: Fix missing locking around retry adding new subreqs Fix netfs_retry_read_subrequests() and netfs_retry_write_stream() to take the appropriate lock when adding extra subrequests into stream->subrequests. Fixes: e2d46f2ec332 ("netfs: Change the read result collector to only use one work item") Fixes: 288ace2f57c9 ("netfs: New writeback implementation") Closes: https://sashiko.dev/#/patchset/20260425125426.3855807-1-dhowells%40redhat.com Signed-off-by: David Howells Link: https://patch.msgid.link/20260512123404.719402-3-dhowells@redhat.com cc: Paulo Alcantara cc: netfs@lists.linux.dev cc: linux-fsdevel@vger.kernel.org Signed-off-by: Christian Brauner --- fs/netfs/read_retry.c | 6 +++++- fs/netfs/write_retry.c | 6 +++++- 2 files changed, 10 insertions(+), 2 deletions(-) diff --git a/fs/netfs/read_retry.c b/fs/netfs/read_retry.c index cca9ac43c077..5ec548b996d6 100644 --- a/fs/netfs/read_retry.c +++ b/fs/netfs/read_retry.c @@ -175,7 +175,9 @@ static void netfs_retry_read_subrequests(struct netfs_io_request *rreq) list_for_each_entry_safe_from(subreq, tmp, &stream->subrequests, rreq_link) { trace_netfs_sreq(subreq, netfs_sreq_trace_superfluous); + spin_lock(&rreq->lock); list_del(&subreq->rreq_link); + spin_unlock(&rreq->lock); netfs_put_subrequest(subreq, netfs_sreq_trace_put_done); if (subreq == to) break; @@ -203,8 +205,10 @@ static void netfs_retry_read_subrequests(struct netfs_io_request *rreq) refcount_read(&subreq->ref), netfs_sreq_trace_new); + spin_lock(&rreq->lock); list_add(&subreq->rreq_link, &to->rreq_link); - to = list_next_entry(to, rreq_link); + spin_unlock(&rreq->lock); + to = subreq; trace_netfs_sreq(subreq, netfs_sreq_trace_retry); stream->sreq_max_len = umin(len, rreq->rsize); diff --git a/fs/netfs/write_retry.c b/fs/netfs/write_retry.c index 29489a23a220..32735abfa03f 100644 --- a/fs/netfs/write_retry.c +++ b/fs/netfs/write_retry.c @@ -130,7 +130,9 @@ static void netfs_retry_write_stream(struct netfs_io_request *wreq, list_for_each_entry_safe_from(subreq, tmp, &stream->subrequests, rreq_link) { trace_netfs_sreq(subreq, netfs_sreq_trace_discard); + spin_lock(&wreq->lock); list_del(&subreq->rreq_link); + spin_unlock(&wreq->lock); netfs_put_subrequest(subreq, netfs_sreq_trace_put_done); if (subreq == to) break; @@ -153,8 +155,10 @@ static void netfs_retry_write_stream(struct netfs_io_request *wreq, netfs_sreq_trace_new); trace_netfs_sreq(subreq, netfs_sreq_trace_split); + spin_lock(&wreq->lock); list_add(&subreq->rreq_link, &to->rreq_link); - to = list_next_entry(to, rreq_link); + spin_unlock(&wreq->lock); + to = subreq; trace_netfs_sreq(subreq, netfs_sreq_trace_retry); stream->sreq_max_len = len; -- cgit v1.2.3 From b5782e2d462c028096f922abca46318cec890670 Mon Sep 17 00:00:00 2001 From: David Howells Date: Tue, 12 May 2026 13:33:40 +0100 Subject: netfs: Fix missing barriers when accessing stream->subrequests locklessly The list of subrequests attached to stream->subrequests is accessed without locks by netfs_collect_read_results() and netfs_collect_write_results(), and then they access subreq->flags without taking a barrier after getting the subreq pointer from the list. Relatedly, the functions that build the list don't use any sort of write barrier when constructing the list to make sure that the NETFS_SREQ_IN_PROGRESS flag is perceived to be set first if no lock is taken. Fix this by: (1) Add a new list_add_tail_release() function that uses a release barrier to set the pointer to the new member of the list. (2) Add a new list_first_entry_or_null_acquire() function that uses an acquire barrier to read the pointer to the first member in a list (or return NULL). (3) Use list_add_tail_release() when adding a subreq to ->subrequests. (4) Use list_first_entry_or_null_acquire() when initially accessing the front of the list (when an item is removed, the pointer to the new front iterm is obtained under the same lock). Fixes: e2d46f2ec332 ("netfs: Change the read result collector to only use one work item") Fixes: 288ace2f57c9 ("netfs: New writeback implementation") Link: https://sashiko.dev/#/patchset/20260326104544.509518-1-dhowells%40redhat.com Signed-off-by: David Howells Link: https://patch.msgid.link/20260512123404.719402-4-dhowells@redhat.com cc: Paulo Alcantara cc: netfs@lists.linux.dev cc: linux-fsdevel@vger.kernel.org Signed-off-by: Christian Brauner --- fs/netfs/buffered_read.c | 3 ++- fs/netfs/misc.c | 1 + fs/netfs/read_collect.c | 6 ++++-- fs/netfs/write_collect.c | 6 ++++-- fs/netfs/write_issue.c | 3 ++- include/linux/list.h | 37 +++++++++++++++++++++++++++++++++++++ 6 files changed, 50 insertions(+), 6 deletions(-) diff --git a/fs/netfs/buffered_read.c b/fs/netfs/buffered_read.c index a27ed501b6d4..15d73026ff64 100644 --- a/fs/netfs/buffered_read.c +++ b/fs/netfs/buffered_read.c @@ -168,7 +168,8 @@ void netfs_queue_read(struct netfs_io_request *rreq, * remove entries off of the front. */ spin_lock(&rreq->lock); - list_add_tail(&subreq->rreq_link, &stream->subrequests); + /* Write IN_PROGRESS before pointer to new subreq */ + list_add_tail_release(&subreq->rreq_link, &stream->subrequests); if (list_is_first(&subreq->rreq_link, &stream->subrequests)) { if (!stream->active) { stream->collected_to = subreq->start; diff --git a/fs/netfs/misc.c b/fs/netfs/misc.c index 6df89c92b10b..21357907b7ee 100644 --- a/fs/netfs/misc.c +++ b/fs/netfs/misc.c @@ -356,6 +356,7 @@ void netfs_wait_for_in_progress_stream(struct netfs_io_request *rreq, DEFINE_WAIT(myself); list_for_each_entry(subreq, &stream->subrequests, rreq_link) { + smp_rmb(); /* Read ->next before IN_PROGRESS. */ if (!netfs_check_subreq_in_progress(subreq)) continue; diff --git a/fs/netfs/read_collect.c b/fs/netfs/read_collect.c index d2d902f46627..3c9b847885c2 100644 --- a/fs/netfs/read_collect.c +++ b/fs/netfs/read_collect.c @@ -205,8 +205,10 @@ reassess: * in progress. The issuer thread may be adding stuff to the tail * whilst we're doing this. */ - front = list_first_entry_or_null(&stream->subrequests, - struct netfs_io_subrequest, rreq_link); + front = list_first_entry_or_null_acquire(&stream->subrequests, + struct netfs_io_subrequest, rreq_link); + /* Read first subreq pointer before IN_PROGRESS flag. */ + while (front) { size_t transferred; diff --git a/fs/netfs/write_collect.c b/fs/netfs/write_collect.c index b194447f4b11..7fbf50907a7f 100644 --- a/fs/netfs/write_collect.c +++ b/fs/netfs/write_collect.c @@ -228,8 +228,10 @@ reassess_streams: if (!smp_load_acquire(&stream->active)) continue; - front = list_first_entry_or_null(&stream->subrequests, - struct netfs_io_subrequest, rreq_link); + front = list_first_entry_or_null_acquire(&stream->subrequests, + struct netfs_io_subrequest, rreq_link); + /* Read first subreq pointer before IN_PROGRESS flag. */ + while (front) { trace_netfs_collect_sreq(wreq, front); //_debug("sreq [%x] %llx %zx/%zx", diff --git a/fs/netfs/write_issue.c b/fs/netfs/write_issue.c index 2db688f94125..b0e9690bb90c 100644 --- a/fs/netfs/write_issue.c +++ b/fs/netfs/write_issue.c @@ -204,7 +204,8 @@ void netfs_prepare_write(struct netfs_io_request *wreq, * remove entries off of the front. */ spin_lock(&wreq->lock); - list_add_tail(&subreq->rreq_link, &stream->subrequests); + /* Write IN_PROGRESS before pointer to new subreq */ + list_add_tail_release(&subreq->rreq_link, &stream->subrequests); if (list_is_first(&subreq->rreq_link, &stream->subrequests)) { if (!stream->active) { stream->collected_to = subreq->start; diff --git a/include/linux/list.h b/include/linux/list.h index 00ea8e5fb88b..09d979976b3b 100644 --- a/include/linux/list.h +++ b/include/linux/list.h @@ -191,6 +191,29 @@ static inline void list_add_tail(struct list_head *new, struct list_head *head) __list_add(new, head->prev, head); } +/** + * list_add_tail_release - add a new entry with release barrier + * @new: new entry to be added + * @head: list head to add it before + * + * Insert a new entry before the specified head, using a release barrier to set + * the ->next pointer that points to it. This is useful for implementing + * queues, in particular one that the elements will be walked through forwards + * locklessly. + */ +static inline void list_add_tail_release(struct list_head *new, + struct list_head *head) +{ + struct list_head *prev = head->prev; + + if (__list_add_valid(new, prev, head)) { + new->next = head; + new->prev = prev; + head->prev = new; + smp_store_release(&prev->next, new); + } +} + /* * Delete a list entry by making the prev/next entries * point to each other. @@ -644,6 +667,20 @@ static inline void list_splice_tail_init(struct list_head *list, pos__ != head__ ? list_entry(pos__, type, member) : NULL; \ }) +/** + * list_first_entry_or_null_acquire - get the first element from a list with barrier + * @ptr: the list head to take the element from. + * @type: the type of the struct this is embedded in. + * @member: the name of the list_head within the struct. + * + * Note that if the list is empty, it returns NULL. + */ +#define list_first_entry_or_null_acquire(ptr, type, member) ({ \ + struct list_head *head__ = (ptr); \ + struct list_head *pos__ = smp_load_acquire(&head__->next); \ + pos__ != head__ ? list_entry(pos__, type, member) : NULL; \ +}) + /** * list_last_entry_or_null - get the last element from a list * @ptr: the list head to take the element from. -- cgit v1.2.3 From 8a8c0cfdf4658fc5b295b7fc87be56e0d76741f4 Mon Sep 17 00:00:00 2001 From: David Howells Date: Tue, 12 May 2026 13:33:41 +0100 Subject: netfs: Fix netfs_read_to_pagecache() to pause on subreq failure Fix netfs_read_to_pagecache() so that it pauses the generation of new subrequests if an already-issued subrequest fails. Fixes: ee4cdf7ba857 ("netfs: Speed up buffered reading") Closes: https://sashiko.dev/#/patchset/20260425125426.3855807-1-dhowells%40redhat.com Signed-off-by: David Howells Link: https://patch.msgid.link/20260512123404.719402-5-dhowells@redhat.com cc: Paulo Alcantara cc: netfs@lists.linux.dev cc: linux-fsdevel@vger.kernel.org Signed-off-by: Christian Brauner --- fs/netfs/buffered_read.c | 5 +++++ 1 file changed, 5 insertions(+) diff --git a/fs/netfs/buffered_read.c b/fs/netfs/buffered_read.c index 15d73026ff64..fee0aebf5a3d 100644 --- a/fs/netfs/buffered_read.c +++ b/fs/netfs/buffered_read.c @@ -300,6 +300,11 @@ static void netfs_read_to_pagecache(struct netfs_io_request *rreq, } netfs_issue_read(rreq, subreq); + + if (test_bit(NETFS_RREQ_PAUSE, &rreq->flags)) + netfs_wait_for_paused_read(rreq); + if (test_bit(NETFS_RREQ_FAILED, &rreq->flags)) + break; cond_resched(); } while (size > 0); -- cgit v1.2.3 From 2c8f4742bb76117d735f92a3932d85239b16c494 Mon Sep 17 00:00:00 2001 From: David Howells Date: Tue, 12 May 2026 13:33:42 +0100 Subject: netfs: Fix potential for tearing in ->remote_i_size and ->zero_point Fix potential tearing in using ->remote_i_size and ->zero_point by copying i_size_read() and i_size_write() and using the same seqcount as for i_size. We need to make sure that netfslib and the filesystems that use it always hold i_lock whilst updating any of the sizes to prevent i_size_seqcount from getting corrupted. Fixes: 4058f742105e ("netfs: Keep track of the actual remote file size") Fixes: 100ccd18bb41 ("netfs: Optimise away reads above the point at which there can be no data") Closes: https://sashiko.dev/#/patchset/20260414082004.3756080-1-dhowells%40redhat.com Signed-off-by: David Howells Link: https://patch.msgid.link/20260512123404.719402-6-dhowells@redhat.com cc: Paulo Alcantara cc: Matthew Wilcox cc: netfs@lists.linux.dev cc: linux-fsdevel@vger.kernel.org Signed-off-by: Christian Brauner --- fs/9p/v9fs_vfs.h | 13 -- fs/9p/vfs_inode.c | 6 +- fs/9p/vfs_inode_dotl.c | 12 +- fs/afs/file.c | 24 +++- fs/afs/inode.c | 31 +++-- fs/afs/internal.h | 11 +- fs/afs/write.c | 2 +- fs/netfs/buffered_read.c | 6 +- fs/netfs/buffered_write.c | 2 +- fs/netfs/direct_write.c | 6 +- fs/netfs/misc.c | 32 +++-- fs/netfs/write_collect.c | 9 +- fs/smb/client/cifsfs.c | 38 ++++-- fs/smb/client/cifssmb.c | 3 +- fs/smb/client/file.c | 13 +- fs/smb/client/inode.c | 14 ++- fs/smb/client/readdir.c | 3 +- fs/smb/client/smb2ops.c | 42 ++++--- fs/smb/client/smb2pdu.c | 3 +- include/linux/netfs.h | 293 ++++++++++++++++++++++++++++++++++++++++++++-- 20 files changed, 450 insertions(+), 113 deletions(-) diff --git a/fs/9p/v9fs_vfs.h b/fs/9p/v9fs_vfs.h index d3aefbec4de6..34c115d7c250 100644 --- a/fs/9p/v9fs_vfs.h +++ b/fs/9p/v9fs_vfs.h @@ -75,17 +75,4 @@ static inline void v9fs_invalidate_inode_attr(struct inode *inode) int v9fs_open_to_dotl_flags(int flags); -static inline void v9fs_i_size_write(struct inode *inode, loff_t i_size) -{ - /* - * 32-bit need the lock, concurrent updates could break the - * sequences and make i_size_read() loop forever. - * 64-bit updates are atomic and can skip the locking. - */ - if (sizeof(i_size) > sizeof(long)) - spin_lock(&inode->i_lock); - i_size_write(inode, i_size); - if (sizeof(i_size) > sizeof(long)) - spin_unlock(&inode->i_lock); -} #endif diff --git a/fs/9p/vfs_inode.c b/fs/9p/vfs_inode.c index d1508b1fe109..f468acb8ee7d 100644 --- a/fs/9p/vfs_inode.c +++ b/fs/9p/vfs_inode.c @@ -1141,11 +1141,13 @@ v9fs_stat2inode(struct p9_wstat *stat, struct inode *inode, mode |= inode->i_mode & ~S_IALLUGO; inode->i_mode = mode; - v9inode->netfs.remote_i_size = stat->length; + spin_lock(&inode->i_lock); + netfs_write_remote_i_size(inode, stat->length); if (!(flags & V9FS_STAT2INODE_KEEP_ISIZE)) - v9fs_i_size_write(inode, stat->length); + i_size_write(inode, stat->length); /* not real number of blocks, but 512 byte ones ... */ inode->i_blocks = (stat->length + 512 - 1) >> 9; + spin_unlock(&inode->i_lock); v9inode->cache_validity &= ~V9FS_INO_INVALID_ATTR; } diff --git a/fs/9p/vfs_inode_dotl.c b/fs/9p/vfs_inode_dotl.c index 71796a89bcf4..141fb54db65d 100644 --- a/fs/9p/vfs_inode_dotl.c +++ b/fs/9p/vfs_inode_dotl.c @@ -634,10 +634,12 @@ v9fs_stat2inode_dotl(struct p9_stat_dotl *stat, struct inode *inode, mode |= inode->i_mode & ~S_IALLUGO; inode->i_mode = mode; - v9inode->netfs.remote_i_size = stat->st_size; + spin_lock(&inode->i_lock); + netfs_write_remote_i_size(inode, stat->st_size); if (!(flags & V9FS_STAT2INODE_KEEP_ISIZE)) - v9fs_i_size_write(inode, stat->st_size); + i_size_write(inode, stat->st_size); inode->i_blocks = stat->st_blocks; + spin_unlock(&inode->i_lock); } else { if (stat->st_result_mask & P9_STATS_ATIME) { inode_set_atime(inode, stat->st_atime_sec, @@ -662,13 +664,15 @@ v9fs_stat2inode_dotl(struct p9_stat_dotl *stat, struct inode *inode, mode |= inode->i_mode & ~S_IALLUGO; inode->i_mode = mode; } + spin_lock(&inode->i_lock); if (!(flags & V9FS_STAT2INODE_KEEP_ISIZE) && stat->st_result_mask & P9_STATS_SIZE) { - v9inode->netfs.remote_i_size = stat->st_size; - v9fs_i_size_write(inode, stat->st_size); + netfs_write_remote_i_size(inode, stat->st_size); + i_size_write(inode, stat->st_size); } if (stat->st_result_mask & P9_STATS_BLOCKS) inode->i_blocks = stat->st_blocks; + spin_unlock(&inode->i_lock); } if (stat->st_result_mask & P9_STATS_GEN) inode->i_generation = stat->st_gen; diff --git a/fs/afs/file.c b/fs/afs/file.c index 85696ac984cc..0467742bfeee 100644 --- a/fs/afs/file.c +++ b/fs/afs/file.c @@ -427,21 +427,35 @@ static void afs_free_request(struct netfs_io_request *rreq) afs_put_wb_key(rreq->netfs_priv2); } -static void afs_update_i_size(struct inode *inode, loff_t new_i_size) +/* + * Set the file size and block count, taking ->cb_lock and ->i_lock to maintain + * coherency and prevent 64-bit tearing on 32-bit arches. + * + * Also, estimate the number of 512 bytes blocks used, rounded up to nearest 1K + * for consistency with other AFS clients. + */ +void afs_set_i_size(struct afs_vnode *vnode, loff_t new_i_size) { - struct afs_vnode *vnode = AFS_FS_I(inode); + struct inode *inode = &vnode->netfs.inode; loff_t i_size; write_seqlock(&vnode->cb_lock); - i_size = i_size_read(&vnode->netfs.inode); + spin_lock(&inode->i_lock); + i_size = i_size_read(inode); if (new_i_size > i_size) { - i_size_write(&vnode->netfs.inode, new_i_size); - inode_set_bytes(&vnode->netfs.inode, new_i_size); + i_size_write(inode, new_i_size); + inode_set_bytes(inode, round_up(new_i_size, 1024)); } + spin_unlock(&inode->i_lock); write_sequnlock(&vnode->cb_lock); fscache_update_cookie(afs_vnode_cache(vnode), NULL, &new_i_size); } +static void afs_update_i_size(struct inode *inode, loff_t new_i_size) +{ + afs_set_i_size(AFS_FS_I(inode), new_i_size); +} + static void afs_netfs_invalidate_cache(struct netfs_io_request *wreq) { struct afs_vnode *vnode = AFS_FS_I(wreq->inode); diff --git a/fs/afs/inode.c b/fs/afs/inode.c index a5173434f786..19fe2e392885 100644 --- a/fs/afs/inode.c +++ b/fs/afs/inode.c @@ -224,7 +224,8 @@ static int afs_inode_init_from_status(struct afs_operation *op, return afs_protocol_error(NULL, afs_eproto_file_type); } - afs_set_i_size(vnode, status->size); + i_size_write(inode, status->size); + inode_set_bytes(inode, status->size); afs_set_netfs_context(vnode); vnode->invalid_before = status->data_version; @@ -253,7 +254,8 @@ static void afs_apply_status(struct afs_operation *op, { struct afs_file_status *status = &vp->scb.status; struct afs_vnode *vnode = vp->vnode; - struct inode *inode = &vnode->netfs.inode; + struct netfs_inode *ictx = &vnode->netfs; + struct inode *inode = &ictx->inode; struct timespec64 t; umode_t mode; bool unexpected_jump = false; @@ -336,6 +338,8 @@ static void afs_apply_status(struct afs_operation *op, } if (data_changed) { + unsigned long long zero_point, size = status->size; + inode_set_iversion_raw(inode, status->data_version); /* Only update the size if the data version jumped. If the @@ -343,16 +347,25 @@ static void afs_apply_status(struct afs_operation *op, * idea of what the size should be that's not the same as * what's on the server. */ - vnode->netfs.remote_i_size = status->size; - if (change_size || status->size > i_size_read(inode)) { - afs_set_i_size(vnode, status->size); + spin_lock(&inode->i_lock); + + if (change_size || size > i_size_read(inode)) { + /* We can read the sizes directly as we hold i_lock. */ + zero_point = ictx->_zero_point; + if (unexpected_jump) - vnode->netfs.zero_point = status->size; + zero_point = size; + netfs_write_sizes(inode, size, size, zero_point); + inode_set_bytes(inode, size); inode_set_ctime_to_ts(inode, t); inode_set_atime_to_ts(inode, t); + } else { + netfs_write_remote_i_size(inode, size); } + spin_unlock(&inode->i_lock); + if (op->ops == &afs_fetch_data_operation) - op->fetch.subreq->rreq->i_size = status->size; + op->fetch.subreq->rreq->i_size = size; } } @@ -709,7 +722,7 @@ int afs_getattr(struct mnt_idmap *idmap, const struct path *path, * it, but we need to give userspace the server's size. */ if (S_ISDIR(inode->i_mode)) - stat->size = vnode->netfs.remote_i_size; + stat->size = netfs_read_remote_i_size(inode); } while (read_seqretry(&vnode->cb_lock, seq)); return 0; @@ -889,7 +902,7 @@ int afs_setattr(struct mnt_idmap *idmap, struct dentry *dentry, */ if (!(attr->ia_valid & (supported & ~ATTR_SIZE & ~ATTR_MTIME)) && attr->ia_size < i_size && - attr->ia_size > vnode->netfs.remote_i_size) { + attr->ia_size > netfs_read_remote_i_size(inode)) { truncate_setsize(inode, attr->ia_size); netfs_resize_file(&vnode->netfs, size, false); fscache_resize_cookie(afs_vnode_cache(vnode), diff --git a/fs/afs/internal.h b/fs/afs/internal.h index 599353c33337..816dc848ea71 100644 --- a/fs/afs/internal.h +++ b/fs/afs/internal.h @@ -1157,6 +1157,7 @@ extern int afs_open(struct inode *, struct file *); extern int afs_release(struct inode *, struct file *); void afs_fetch_data_async_rx(struct work_struct *work); void afs_fetch_data_immediate_cancel(struct afs_call *call); +void afs_set_i_size(struct afs_vnode *vnode, loff_t new_i_size); /* * flock.c @@ -1758,16 +1759,6 @@ static inline void afs_update_dentry_version(struct afs_operation *op, (void *)(unsigned long)dir_vp->scb.status.data_version; } -/* - * Set the file size and block count. Estimate the number of 512 bytes blocks - * used, rounded up to nearest 1K for consistency with other AFS clients. - */ -static inline void afs_set_i_size(struct afs_vnode *vnode, u64 size) -{ - i_size_write(&vnode->netfs.inode, size); - vnode->netfs.inode.i_blocks = ((size + 1023) >> 10) << 1; -} - /* * Check for a conflicting operation on a directory that we just unlinked from. * If someone managed to sneak a link or an unlink in on the file we just diff --git a/fs/afs/write.c b/fs/afs/write.c index fcfed9d24e0a..7f34b939706a 100644 --- a/fs/afs/write.c +++ b/fs/afs/write.c @@ -142,7 +142,7 @@ static void afs_issue_write_worker(struct work_struct *work) afs_begin_vnode_operation(op); op->store.write_iter = &subreq->io_iter; - op->store.i_size = umax(pos + len, vnode->netfs.remote_i_size); + op->store.i_size = umax(pos + len, netfs_read_remote_i_size(&vnode->netfs.inode)); op->mtime = inode_get_mtime(&vnode->netfs.inode); afs_wait_for_operation(op); diff --git a/fs/netfs/buffered_read.c b/fs/netfs/buffered_read.c index fee0aebf5a3d..ebd84a6cc3f0 100644 --- a/fs/netfs/buffered_read.c +++ b/fs/netfs/buffered_read.c @@ -209,7 +209,6 @@ static void netfs_issue_read(struct netfs_io_request *rreq, static void netfs_read_to_pagecache(struct netfs_io_request *rreq, struct readahead_control *ractl) { - struct netfs_inode *ictx = netfs_inode(rreq->inode); unsigned long long start = rreq->start; ssize_t size = rreq->len; int ret = 0; @@ -233,7 +232,8 @@ static void netfs_read_to_pagecache(struct netfs_io_request *rreq, source = netfs_cache_prepare_read(rreq, subreq, rreq->i_size); subreq->source = source; if (source == NETFS_DOWNLOAD_FROM_SERVER) { - unsigned long long zp = umin(ictx->zero_point, rreq->i_size); + unsigned long long zero_point = netfs_read_zero_point(rreq->inode); + unsigned long long zp = umin(zero_point, rreq->i_size); size_t len = subreq->len; if (unlikely(rreq->origin == NETFS_READ_SINGLE)) @@ -249,7 +249,7 @@ static void netfs_read_to_pagecache(struct netfs_io_request *rreq, pr_err("ZERO-LEN READ: R=%08x[%x] l=%zx/%zx s=%llx z=%llx i=%llx", rreq->debug_id, subreq->debug_index, subreq->len, size, - subreq->start, ictx->zero_point, rreq->i_size); + subreq->start, zero_point, rreq->i_size); netfs_cancel_read(subreq, ret); break; } diff --git a/fs/netfs/buffered_write.c b/fs/netfs/buffered_write.c index 05ea5b0cc0e8..b6ecd059dc4f 100644 --- a/fs/netfs/buffered_write.c +++ b/fs/netfs/buffered_write.c @@ -230,7 +230,7 @@ ssize_t netfs_perform_write(struct kiocb *iocb, struct iov_iter *iter, * server would just return a block of zeros or a short read if * we try to read it. */ - if (fpos >= ctx->zero_point) { + if (fpos >= netfs_read_zero_point(inode)) { folio_zero_segment(folio, 0, offset); copied = copy_folio_from_iter_atomic(folio, offset, part, iter); if (unlikely(copied == 0)) diff --git a/fs/netfs/direct_write.c b/fs/netfs/direct_write.c index f9ab69de3e29..25f8ceb15fad 100644 --- a/fs/netfs/direct_write.c +++ b/fs/netfs/direct_write.c @@ -376,8 +376,10 @@ ssize_t netfs_unbuffered_write_iter(struct kiocb *iocb, struct iov_iter *from) if (ret < 0) goto out; end = iocb->ki_pos + iov_iter_count(from); - if (end > ictx->zero_point) - ictx->zero_point = end; + spin_lock(&inode->i_lock); + if (end > ictx->_zero_point) + netfs_write_zero_point(inode, end); + spin_unlock(&inode->i_lock); fscache_invalidate(netfs_i_cookie(ictx), NULL, i_size_read(inode), FSCACHE_INVAL_DIO_WRITE); diff --git a/fs/netfs/misc.c b/fs/netfs/misc.c index 21357907b7ee..bad661ff2bec 100644 --- a/fs/netfs/misc.c +++ b/fs/netfs/misc.c @@ -211,18 +211,25 @@ EXPORT_SYMBOL(netfs_clear_inode_writeback); void netfs_invalidate_folio(struct folio *folio, size_t offset, size_t length) { struct netfs_folio *finfo; - struct netfs_inode *ctx = netfs_inode(folio_inode(folio)); + struct inode *inode = folio_inode(folio); + struct netfs_inode *ctx = netfs_inode(inode); size_t flen = folio_size(folio); _enter("{%lx},%zx,%zx", folio->index, offset, length); if (offset == 0 && length == flen) { - unsigned long long i_size = i_size_read(&ctx->inode); + unsigned long long i_size, remote_i_size, zero_point; unsigned long long fpos = folio_pos(folio), end; + netfs_read_sizes(inode, &i_size, &remote_i_size, &zero_point); end = umin(fpos + flen, i_size); - if (fpos < i_size && end > ctx->zero_point) - ctx->zero_point = end; + if (fpos < i_size && end > zero_point) { + spin_lock(&inode->i_lock); + end = umin(fpos + flen, inode->i_size); + if (fpos < i_size && end > ctx->_zero_point) + netfs_write_zero_point(inode, end); + spin_unlock(&inode->i_lock); + } } folio_wait_private_2(folio); /* [DEPRECATED] */ @@ -292,15 +299,22 @@ EXPORT_SYMBOL(netfs_invalidate_folio); */ bool netfs_release_folio(struct folio *folio, gfp_t gfp) { - struct netfs_inode *ctx = netfs_inode(folio_inode(folio)); - unsigned long long end; + struct inode *inode = folio_inode(folio); + struct netfs_inode *ctx = netfs_inode(inode); + unsigned long long i_size, remote_i_size, zero_point, end; if (folio_test_dirty(folio)) return false; - end = umin(folio_next_pos(folio), i_size_read(&ctx->inode)); - if (end > ctx->zero_point) - ctx->zero_point = end; + netfs_read_sizes(inode, &i_size, &remote_i_size, &zero_point); + end = umin(folio_next_pos(folio), i_size); + if (end > zero_point) { + spin_lock(&inode->i_lock); + end = umin(folio_next_pos(folio), inode->i_size); + if (end > ctx->_zero_point) + netfs_write_zero_point(inode, end); + spin_unlock(&inode->i_lock); + } if (folio_test_private(folio)) return false; diff --git a/fs/netfs/write_collect.c b/fs/netfs/write_collect.c index 7fbf50907a7f..24fc2bb2f8a4 100644 --- a/fs/netfs/write_collect.c +++ b/fs/netfs/write_collect.c @@ -57,7 +57,8 @@ static void netfs_dump_request(const struct netfs_io_request *rreq) int netfs_folio_written_back(struct folio *folio) { enum netfs_folio_trace why = netfs_folio_trace_clear; - struct netfs_inode *ictx = netfs_inode(folio->mapping->host); + struct inode *inode = folio_inode(folio); + struct netfs_inode *ictx = netfs_inode(inode); struct netfs_folio *finfo; struct netfs_group *group = NULL; int gcount = 0; @@ -69,8 +70,10 @@ int netfs_folio_written_back(struct folio *folio) unsigned long long fend; fend = folio_pos(folio) + finfo->dirty_offset + finfo->dirty_len; - if (fend > ictx->zero_point) - ictx->zero_point = fend; + spin_lock(&ictx->inode.i_lock); + if (fend > ictx->_zero_point) + netfs_write_zero_point(inode, fend); + spin_unlock(&ictx->inode.i_lock); folio_detach_private(folio); group = finfo->netfs_group; diff --git a/fs/smb/client/cifsfs.c b/fs/smb/client/cifsfs.c index 9f76b0347fa9..feac491c5070 100644 --- a/fs/smb/client/cifsfs.c +++ b/fs/smb/client/cifsfs.c @@ -434,7 +434,8 @@ cifs_alloc_inode(struct super_block *sb) spin_lock_init(&cifs_inode->writers_lock); cifs_inode->writers = 0; cifs_inode->netfs.inode.i_blkbits = 14; /* 2**14 = CIFS_MAX_MSGSIZE */ - cifs_inode->netfs.remote_i_size = 0; + cifs_inode->netfs._remote_i_size = 0; + cifs_inode->netfs._zero_point = 0; cifs_inode->uniqueid = 0; cifs_inode->createtime = 0; cifs_inode->epoch = 0; @@ -1303,7 +1304,8 @@ static loff_t cifs_remap_file_range(struct file *src_file, loff_t off, struct cifsFileInfo *smb_file_src = src_file->private_data; struct cifsFileInfo *smb_file_target = dst_file->private_data; struct cifs_tcon *target_tcon, *src_tcon; - unsigned long long destend, fstart, fend, old_size, new_size; + unsigned long long i_size, old_size, new_size, zero_point; + unsigned long long destend, fstart, fend; unsigned int xid; int rc; @@ -1347,7 +1349,7 @@ static loff_t cifs_remap_file_range(struct file *src_file, loff_t off, * Advance the EOF marker after the flush above to the end of the range * if it's short of that. */ - if (src_cifsi->netfs.remote_i_size < off + len) { + if (netfs_read_remote_i_size(src_inode) < off + len) { rc = cifs_precopy_set_eof(src_inode, src_cifsi, src_tcon, xid, off + len); if (rc < 0) goto unlock; @@ -1368,16 +1370,18 @@ static loff_t cifs_remap_file_range(struct file *src_file, loff_t off, rc = cifs_flush_folio(target_inode, destend, &fstart, &fend, false); if (rc) goto unlock; - if (fend > target_cifsi->netfs.zero_point) - target_cifsi->netfs.zero_point = fend + 1; - old_size = target_cifsi->netfs.remote_i_size; + + spin_lock(&target_inode->i_lock); + if (fend > zero_point) + netfs_write_zero_point(target_inode, fend + 1); + i_size = target_inode->i_size; + spin_unlock(&target_inode->i_lock); /* Discard all the folios that overlap the destination region. */ cifs_dbg(FYI, "about to discard pages %llx-%llx\n", fstart, fend); truncate_inode_pages_range(&target_inode->i_data, fstart, fend); - fscache_invalidate(cifs_inode_cookie(target_inode), NULL, - i_size_read(target_inode), 0); + fscache_invalidate(cifs_inode_cookie(target_inode), NULL, i_size, 0); rc = -EOPNOTSUPP; if (target_tcon->ses->server->ops->duplicate_extents) { @@ -1402,8 +1406,12 @@ static loff_t cifs_remap_file_range(struct file *src_file, loff_t off, rc = -EINVAL; } } - if (rc == 0 && new_size > target_cifsi->netfs.zero_point) - target_cifsi->netfs.zero_point = new_size; + if (rc == 0) { + spin_lock(&target_inode->i_lock); + if (new_size > target_cifsi->netfs._zero_point) + netfs_write_zero_point(target_inode, new_size); + spin_unlock(&target_inode->i_lock); + } } /* force revalidate of size and timestamps of target file now @@ -1474,7 +1482,7 @@ ssize_t cifs_file_copychunk_range(unsigned int xid, * Advance the EOF marker after the flush above to the end of the range * if it's short of that. */ - if (src_cifsi->netfs.remote_i_size < off + len) { + if (netfs_read_remote_i_size(src_inode) < off + len) { rc = cifs_precopy_set_eof(src_inode, src_cifsi, src_tcon, xid, off + len); if (rc < 0) goto unlock; @@ -1502,8 +1510,12 @@ ssize_t cifs_file_copychunk_range(unsigned int xid, fscache_resize_cookie(cifs_inode_cookie(target_inode), i_size_read(target_inode)); } - if (rc > 0 && destoff + rc > target_cifsi->netfs.zero_point) - target_cifsi->netfs.zero_point = destoff + rc; + if (rc > 0) { + spin_lock(&target_inode->i_lock); + if (destoff + rc > target_cifsi->netfs._zero_point) + netfs_write_zero_point(target_inode, destoff + rc); + spin_unlock(&target_inode->i_lock); + } } file_accessed(src_file); diff --git a/fs/smb/client/cifssmb.c b/fs/smb/client/cifssmb.c index 3990a9012264..9e27bfa7376b 100644 --- a/fs/smb/client/cifssmb.c +++ b/fs/smb/client/cifssmb.c @@ -1465,6 +1465,7 @@ cifs_readv_callback(struct TCP_Server_Info *server, struct mid_q_entry *mid) struct cifs_io_subrequest *rdata = mid->callback_data; struct netfs_inode *ictx = netfs_inode(rdata->rreq->inode); struct cifs_tcon *tcon = tlink_tcon(rdata->req->cfile->tlink); + struct inode *inode = &ictx->inode; struct smb_rqst rqst = { .rq_iov = rdata->iov, .rq_nvec = 1, .rq_iter = rdata->subreq.io_iter }; @@ -1538,7 +1539,7 @@ do_retry: } else { size_t trans = rdata->subreq.transferred + rdata->got_bytes; if (trans < rdata->subreq.len && - rdata->subreq.start + trans >= ictx->remote_i_size) { + rdata->subreq.start + trans >= netfs_read_remote_i_size(inode)) { rdata->result = 0; __set_bit(NETFS_SREQ_HIT_EOF, &rdata->subreq.flags); } else if (rdata->got_bytes > 0) { diff --git a/fs/smb/client/file.c b/fs/smb/client/file.c index 664a2c223089..b60344125f27 100644 --- a/fs/smb/client/file.c +++ b/fs/smb/client/file.c @@ -2517,18 +2517,23 @@ int cifs_lock(struct file *file, int cmd, struct file_lock *flock) void cifs_write_subrequest_terminated(struct cifs_io_subrequest *wdata, ssize_t result) { struct netfs_io_request *wreq = wdata->rreq; - struct netfs_inode *ictx = netfs_inode(wreq->inode); + struct inode *inode = wreq->inode; + struct netfs_inode *ictx = netfs_inode(inode); loff_t wrend; if (result > 0) { + spin_lock(&inode->i_lock); + wrend = wdata->subreq.start + wdata->subreq.transferred + result; - if (wrend > ictx->zero_point && + if (wrend > ictx->_zero_point && (wdata->rreq->origin == NETFS_UNBUFFERED_WRITE || wdata->rreq->origin == NETFS_DIO_WRITE)) - ictx->zero_point = wrend; - if (wrend > ictx->remote_i_size) + netfs_write_zero_point(inode, wrend); + if (wrend > ictx->_remote_i_size) netfs_resize_file(ictx, wrend, true); + + spin_unlock(&inode->i_lock); } netfs_write_subrequest_terminated(&wdata->subreq, result); diff --git a/fs/smb/client/inode.c b/fs/smb/client/inode.c index 16a5310155d5..9472c0a6c187 100644 --- a/fs/smb/client/inode.c +++ b/fs/smb/client/inode.c @@ -119,7 +119,7 @@ cifs_revalidate_cache(struct inode *inode, struct cifs_fattr *fattr) fattr->cf_mtime = timestamp_truncate(fattr->cf_mtime, inode); mtime = inode_get_mtime(inode); if (timespec64_equal(&mtime, &fattr->cf_mtime) && - cifs_i->netfs.remote_i_size == fattr->cf_eof) { + netfs_read_remote_i_size(inode) == fattr->cf_eof) { cifs_dbg(FYI, "%s: inode %llu is unchanged\n", __func__, cifs_i->uniqueid); return; @@ -173,12 +173,12 @@ cifs_fattr_to_inode(struct inode *inode, struct cifs_fattr *fattr, CIFS_I(inode)->time = 0; /* force reval */ return -ESTALE; } - if (inode_state_read_once(inode) & I_NEW) - CIFS_I(inode)->netfs.zero_point = fattr->cf_eof; - cifs_revalidate_cache(inode, fattr); spin_lock(&inode->i_lock); + if (inode_state_read_once(inode) & I_NEW) + netfs_write_zero_point(inode, fattr->cf_eof); + fattr->cf_mtime = timestamp_truncate(fattr->cf_mtime, inode); fattr->cf_atime = timestamp_truncate(fattr->cf_atime, inode); fattr->cf_ctime = timestamp_truncate(fattr->cf_ctime, inode); @@ -212,7 +212,7 @@ cifs_fattr_to_inode(struct inode *inode, struct cifs_fattr *fattr, else clear_bit(CIFS_INO_DELETE_PENDING, &cifs_i->flags); - cifs_i->netfs.remote_i_size = fattr->cf_eof; + netfs_write_remote_i_size(inode, fattr->cf_eof); /* * Can't safely change the file size here if the client is writing to * it due to potential races. @@ -2772,7 +2772,9 @@ cifs_revalidate_mapping(struct inode *inode) if (cifs_sb_flags(cifs_sb) & CIFS_MOUNT_RW_CACHE) goto skip_invalidate; - cifs_inode->netfs.zero_point = cifs_inode->netfs.remote_i_size; + spin_lock(&inode->i_lock); + netfs_write_zero_point(inode, netfs_inode(inode)->_remote_i_size); + spin_unlock(&inode->i_lock); rc = filemap_invalidate_inode(inode, true, 0, LLONG_MAX); if (rc) { cifs_dbg(VFS, "%s: invalidate inode %p failed with rc %d\n", diff --git a/fs/smb/client/readdir.c b/fs/smb/client/readdir.c index be22bbc4a65a..e860fa08b5e3 100644 --- a/fs/smb/client/readdir.c +++ b/fs/smb/client/readdir.c @@ -143,7 +143,8 @@ retry: fattr->cf_rdev = inode->i_rdev; fattr->cf_uid = inode->i_uid; fattr->cf_gid = inode->i_gid; - fattr->cf_eof = CIFS_I(inode)->netfs.remote_i_size; + fattr->cf_eof = + netfs_read_remote_i_size(inode); fattr->cf_symlink_target = NULL; } else { CIFS_I(inode)->time = 0; diff --git a/fs/smb/client/smb2ops.c b/fs/smb/client/smb2ops.c index e6cb9b144530..0ea3ce1b94ea 100644 --- a/fs/smb/client/smb2ops.c +++ b/fs/smb/client/smb2ops.c @@ -3402,8 +3402,7 @@ static long smb3_zero_range(struct file *file, struct cifs_tcon *tcon, struct inode *inode = file_inode(file); struct cifsInodeInfo *cifsi = CIFS_I(inode); struct cifsFileInfo *cfile = file->private_data; - struct netfs_inode *ictx = netfs_inode(inode); - unsigned long long i_size, new_size, remote_size; + unsigned long long i_size, new_size, remote_i_size, zero_point; long rc; unsigned int xid; @@ -3414,9 +3413,8 @@ static long smb3_zero_range(struct file *file, struct cifs_tcon *tcon, filemap_invalidate_lock(inode->i_mapping); - i_size = i_size_read(inode); - remote_size = ictx->remote_i_size; - if (offset + len >= remote_size && offset < i_size) { + netfs_read_sizes(inode, &i_size, &remote_i_size, &zero_point); + if (offset + len >= remote_i_size && offset < i_size) { unsigned long long top = umin(offset + len, i_size); rc = filemap_write_and_wait_range(inode->i_mapping, offset, top - 1); @@ -3449,9 +3447,11 @@ static long smb3_zero_range(struct file *file, struct cifs_tcon *tcon, cfile->fid.volatile_fid, cfile->pid, new_size); if (rc >= 0) { truncate_setsize(inode, new_size); + spin_lock(&inode->i_lock); netfs_resize_file(&cifsi->netfs, new_size, true); - if (offset < cifsi->netfs.zero_point) - cifsi->netfs.zero_point = offset; + if (offset < cifsi->netfs._zero_point) + netfs_write_zero_point(inode, offset); + spin_unlock(&inode->i_lock); fscache_resize_cookie(cifs_inode_cookie(inode), new_size); } } @@ -3474,7 +3474,7 @@ static long smb3_punch_hole(struct file *file, struct cifs_tcon *tcon, struct inode *inode = file_inode(file); struct cifsFileInfo *cfile = file->private_data; struct file_zero_data_information fsctl_buf; - unsigned long long end = offset + len, i_size, remote_i_size; + unsigned long long end = offset + len, i_size, remote_i_size, zero_point; long rc; unsigned int xid; __u8 set_sparse = 1; @@ -3516,14 +3516,17 @@ static long smb3_punch_hole(struct file *file, struct cifs_tcon *tcon, * that we locally hole-punch the tail of the dirty data, the proposed * EOF update will end up in the wrong place. */ - i_size = i_size_read(inode); - remote_i_size = netfs_inode(inode)->remote_i_size; + netfs_read_sizes(inode, &i_size, &remote_i_size, &zero_point); + if (end > remote_i_size && i_size > remote_i_size) { unsigned long long extend_to = umin(end, i_size); rc = SMB2_set_eof(xid, tcon, cfile->fid.persistent_fid, cfile->fid.volatile_fid, cfile->pid, extend_to); - if (rc >= 0) - netfs_inode(inode)->remote_i_size = extend_to; + if (rc >= 0) { + spin_lock(&inode->i_lock); + netfs_write_remote_i_size(inode, extend_to); + spin_unlock(&inode->i_lock); + } } unlock: @@ -3787,7 +3790,6 @@ static long smb3_collapse_range(struct file *file, struct cifs_tcon *tcon, struct inode *inode = file_inode(file); struct cifsInodeInfo *cifsi = CIFS_I(inode); struct cifsFileInfo *cfile = file->private_data; - struct netfs_inode *ictx = &cifsi->netfs; loff_t old_eof, new_eof; xid = get_xid(); @@ -3805,7 +3807,9 @@ static long smb3_collapse_range(struct file *file, struct cifs_tcon *tcon, goto out_2; truncate_pagecache_range(inode, off, old_eof); - ictx->zero_point = old_eof; + spin_lock(&inode->i_lock); + netfs_write_zero_point(inode, old_eof); + spin_unlock(&inode->i_lock); netfs_wait_for_outstanding_io(inode); rc = smb2_copychunk_range(xid, cfile, cfile, off + len, @@ -3822,8 +3826,10 @@ static long smb3_collapse_range(struct file *file, struct cifs_tcon *tcon, rc = 0; truncate_setsize(inode, new_eof); + spin_lock(&inode->i_lock); netfs_resize_file(&cifsi->netfs, new_eof, true); - ictx->zero_point = new_eof; + netfs_write_zero_point(inode, new_eof); + spin_unlock(&inode->i_lock); fscache_resize_cookie(cifs_inode_cookie(inode), new_eof); out_2: filemap_invalidate_unlock(inode->i_mapping); @@ -3866,13 +3872,17 @@ static long smb3_insert_range(struct file *file, struct cifs_tcon *tcon, goto out_2; truncate_setsize(inode, new_eof); + spin_lock(&inode->i_lock); netfs_resize_file(&cifsi->netfs, i_size_read(inode), true); + spin_unlock(&inode->i_lock); fscache_resize_cookie(cifs_inode_cookie(inode), i_size_read(inode)); rc = smb2_copychunk_range(xid, cfile, cfile, off, count, off + len); if (rc < 0) goto out_2; - cifsi->netfs.zero_point = new_eof; + spin_lock(&inode->i_lock); + netfs_write_zero_point(inode, new_eof); + spin_unlock(&inode->i_lock); rc = smb3_zero_data(file, tcon, off, len, xid); if (rc < 0) diff --git a/fs/smb/client/smb2pdu.c b/fs/smb/client/smb2pdu.c index 995fcdd30681..3bd300347f16 100644 --- a/fs/smb/client/smb2pdu.c +++ b/fs/smb/client/smb2pdu.c @@ -4608,6 +4608,7 @@ smb2_readv_callback(struct TCP_Server_Info *server, struct mid_q_entry *mid) struct netfs_inode *ictx = netfs_inode(rdata->rreq->inode); struct cifs_tcon *tcon = tlink_tcon(rdata->req->cfile->tlink); struct smb2_hdr *shdr = (struct smb2_hdr *)rdata->iov[0].iov_base; + struct inode *inode = &ictx->inode; struct cifs_credits credits = { .value = 0, .instance = 0, @@ -4721,7 +4722,7 @@ do_retry: } else { size_t trans = rdata->subreq.transferred + rdata->got_bytes; if (trans < rdata->subreq.len && - rdata->subreq.start + trans >= ictx->remote_i_size) { + rdata->subreq.start + trans >= netfs_read_remote_i_size(inode)) { __set_bit(NETFS_SREQ_HIT_EOF, &rdata->subreq.flags); rdata->result = 0; } diff --git a/include/linux/netfs.h b/include/linux/netfs.h index ba17ac5bf356..4fd1d796ad73 100644 --- a/include/linux/netfs.h +++ b/include/linux/netfs.h @@ -62,8 +62,8 @@ struct netfs_inode { struct fscache_cookie *cache; #endif struct mutex wb_lock; /* Writeback serialisation */ - loff_t remote_i_size; /* Size of the remote file */ - loff_t zero_point; /* Size after which we assume there's no data + loff_t _remote_i_size; /* Size of the remote file */ + loff_t _zero_point; /* Size after which we assume there's no data * on the server */ atomic_t io_count; /* Number of outstanding reqs */ unsigned long flags; @@ -474,6 +474,254 @@ static inline struct netfs_inode *netfs_inode(struct inode *inode) return container_of(inode, struct netfs_inode, inode); } +/** + * netfs_read_remote_i_size - Read remote_i_size safely + * @inode: The inode to access + * + * Read remote_i_size safely without the potential for tearing on 32-bit + * arches. + * + * NOTE: in a 32bit arch with a preemptable kernel and an UP compile the + * i_size_read/write must be atomic with respect to the local cpu (unlike with + * preempt disabled), but they don't need to be atomic with respect to other + * cpus like in true SMP (so they need either to either locally disable irq + * around the read or for example on x86 they can be still implemented as a + * cmpxchg8b without the need of the lock prefix). For SMP compiles and 64bit + * archs it makes no difference if preempt is enabled or not. + */ +static inline unsigned long long netfs_read_remote_i_size(const struct inode *inode) +{ + const struct netfs_inode *ictx = container_of(inode, struct netfs_inode, inode); + unsigned long long remote_i_size; + +#if BITS_PER_LONG==32 && defined(CONFIG_SMP) + unsigned int seq; + + do { + seq = read_seqcount_begin(&inode->i_size_seqcount); + remote_i_size = ictx->_remote_i_size; + } while (read_seqcount_retry(&inode->i_size_seqcount, seq)); +#elif BITS_PER_LONG==32 && defined(CONFIG_PREEMPTION) + preempt_disable(); + remote_i_size = ictx->_remote_i_size; + preempt_enable(); +#else + /* Pairs with smp_store_release() in netfs_write_remote_i_size() */ + remote_i_size = smp_load_acquire(&ictx->_remote_i_size); +#endif + return remote_i_size; +} + +/* + * netfs_write_remote_i_size - Set remote_i_size safely + * @inode: The inode to access + * @remote_i_size: The new value for the size of the file on the server + * + * Set remote_i_size safely without the potential for tearing on 32-bit arches. + * + * Context: The caller must hold inode->i_lock. + * + * NOTE: unlike netfs_read_remote_i_size(), netfs_write_remote_i_size() does + * need locking around it (normally i_rwsem), otherwise on 32bit/SMP an update + * of i_size_seqcount can be lost, resulting in subsequent i_size_read() calls + * spinning forever. + */ +static inline void netfs_write_remote_i_size(struct inode *inode, + unsigned long long remote_i_size) +{ + struct netfs_inode *ictx = netfs_inode(inode); + +#if BITS_PER_LONG==32 && defined(CONFIG_SMP) + write_seqcount_begin(&inode->i_size_seqcount); + ictx->_remote_i_size = remote_i_size; + write_seqcount_end(&inode->i_size_seqcount); +#elif BITS_PER_LONG==32 && defined(CONFIG_PREEMPTION) + preempt_disable(); + ictx->_remote_i_size = remote_i_size; + preempt_enable(); +#else + /* + * Pairs with smp_load_acquire() in netfs_read_remote_i_size() to + * ensure changes related to inode size (such as page contents) are + * visible before we see the changed inode size. + */ + smp_store_release(&ictx->_remote_i_size, remote_i_size); +#endif +} + +/** + * netfs_read_zero_point - Read zero_point safely + * @inode: The inode to access + * + * Read zero_point safely without the potential for tearing on 32-bit + * arches. + * + * NOTE: in a 32bit arch with a preemptable kernel and an UP compile the + * i_size_read/write must be atomic with respect to the local cpu (unlike with + * preempt disabled), but they don't need to be atomic with respect to other + * cpus like in true SMP (so they need either to either locally disable irq + * around the read or for example on x86 they can be still implemented as a + * cmpxchg8b without the need of the lock prefix). For SMP compiles and 64bit + * archs it makes no difference if preempt is enabled or not. + */ +static inline unsigned long long netfs_read_zero_point(const struct inode *inode) +{ + struct netfs_inode *ictx = container_of(inode, struct netfs_inode, inode); + unsigned long long zero_point; + +#if BITS_PER_LONG==32 && defined(CONFIG_SMP) + unsigned int seq; + + do { + seq = read_seqcount_begin(&inode->i_size_seqcount); + zero_point = ictx->_zero_point; + } while (read_seqcount_retry(&inode->i_size_seqcount, seq)); +#elif BITS_PER_LONG==32 && defined(CONFIG_PREEMPTION) + preempt_disable(); + zero_point = ictx->_zero_point; + preempt_enable(); +#else + /* Pairs with smp_store_release() in netfs_write_zero_point() */ + zero_point = smp_load_acquire(&ictx->_zero_point); +#endif + return zero_point; +} + +/* + * netfs_write_zero_point - Set zero_point safely + * @inode: The inode to access + * @zero_point: The new value for the point beyond which the server has no data + * + * Set zero_point safely without the potential for tearing on 32-bit arches. + * + * Context: The caller must hold inode->i_lock. + * + * NOTE: unlike netfs_read_zero_point(), netfs_write_zero_point() does need + * locking around it (normally i_rwsem), otherwise on 32bit/SMP an update of + * i_size_seqcount can be lost, resulting in subsequent read calls spinning + * forever. + */ +static inline void netfs_write_zero_point(struct inode *inode, + unsigned long long zero_point) +{ + struct netfs_inode *ictx = netfs_inode(inode); + +#if BITS_PER_LONG==32 && defined(CONFIG_SMP) + write_seqcount_begin(&inode->i_size_seqcount); + ictx->_zero_point = zero_point; + write_seqcount_end(&inode->i_size_seqcount); +#elif BITS_PER_LONG==32 && defined(CONFIG_PREEMPTION) + preempt_disable(); + ictx->_zero_point = zero_point; + preempt_enable(); +#else + /* + * Pairs with smp_load_acquire() in netfs_read_zero_point() to + * ensure changes related to inode size (such as page contents) are + * visible before we see the changed inode size. + */ + smp_store_release(&ictx->_zero_point, zero_point); +#endif +} + +/** + * netfs_read_sizes - Read remote_i_size and zero_point safely + * @inode: The inode to access + * @i_size: Where to return the local file size. + * @remote_i_size: Where to return the size of the file on the server + * @zero_point: Where to return the the point beyond which the server has no data + * + * Read remote_i_size and zero_point safely without the potential for tearing + * on 32-bit arches. + * + * NOTE: in a 32bit arch with a preemptable kernel and an UP compile the + * i_size_read/write must be atomic with respect to the local cpu (unlike with + * preempt disabled), but they don't need to be atomic with respect to other + * cpus like in true SMP (so they need either to either locally disable irq + * around the read or for example on x86 they can be still implemented as a + * cmpxchg8b without the need of the lock prefix). For SMP compiles and 64bit + * archs it makes no difference if preempt is enabled or not. + */ +static inline void netfs_read_sizes(const struct inode *inode, + unsigned long long *i_size, + unsigned long long *remote_i_size, + unsigned long long *zero_point) +{ + const struct netfs_inode *ictx = container_of(inode, struct netfs_inode, inode); +#if BITS_PER_LONG==32 && defined(CONFIG_SMP) + unsigned int seq; + + do { + seq = read_seqcount_begin(&inode->i_size_seqcount); + *i_size = inode->i_size; + *remote_i_size = ictx->_remote_i_size; + *zero_point = ictx->_zero_point; + } while (read_seqcount_retry(&inode->i_size_seqcount, seq)); +#elif BITS_PER_LONG==32 && defined(CONFIG_PREEMPTION) + preempt_disable(); + *i_size = inode->i_size; + *remote_i_size = ictx->_remote_i_size; + *zero_point = ictx->_zero_point; + preempt_enable(); +#else + /* Pairs with smp_store_release() in i_size_write() */ + *i_size = smp_load_acquire(&inode->i_size); + /* Pairs with smp_store_release() in netfs_write_remote_i_size() */ + *remote_i_size = smp_load_acquire(&ictx->_remote_i_size); + /* Pairs with smp_store_release() in netfs_write_zero_point() */ + *zero_point = smp_load_acquire(&ictx->_zero_point); +#endif +} + +/* + * netfs_write_sizes - Set i_size, remote_i_size and zero_point safely + * @inode: The inode to access + * @i_size: The new value for the local size of the file + * @remote_i_size: The new value for the size of the file on the server + * @zero_point: The new value for the point beyond which the server has no data + * + * Set both remote_i_size and zero_point safely without the potential for + * tearing on 32-bit arches. + * + * Context: The caller must hold inode->i_lock. + * + * NOTE: unlike netfs_read_zero_point(), netfs_write_zero_point() does need + * locking around it (normally i_rwsem), otherwise on 32bit/SMP an update of + * i_size_seqcount can be lost, resulting in subsequent read calls spinning + * forever. + */ +static inline void netfs_write_sizes(struct inode *inode, + unsigned long long i_size, + unsigned long long remote_i_size, + unsigned long long zero_point) +{ + struct netfs_inode *ictx = netfs_inode(inode); + +#if BITS_PER_LONG==32 && defined(CONFIG_SMP) + write_seqcount_begin(&inode->i_size_seqcount); + inode->i_size = i_size; + ictx->_remote_i_size = remote_i_size; + ictx->_zero_point = zero_point; + write_seqcount_end(&inode->i_size_seqcount); +#elif BITS_PER_LONG==32 && defined(CONFIG_PREEMPTION) + preempt_disable(); + inode->i_size = i_size; + ictx->_remote_i_size = remote_i_size; + ictx->_zero_point = zero_point; + preempt_enable(); +#else + /* + * Pairs with smp_load_acquire() in i_size_read(), + * netfs_read_remote_i_size() and netfs_read_zero_point() to ensure + * changes related to inode size (such as page contents) are visible + * before we see the changed inode size. + */ + smp_store_release(&inode->i_size, i_size); + smp_store_release(&ictx->_remote_i_size, remote_i_size); + smp_store_release(&ictx->_zero_point, zero_point); +#endif +} + /** * netfs_inode_init - Initialise a netfslib inode context * @ctx: The netfs inode to initialise @@ -488,8 +736,8 @@ static inline void netfs_inode_init(struct netfs_inode *ctx, bool use_zero_point) { ctx->ops = ops; - ctx->remote_i_size = i_size_read(&ctx->inode); - ctx->zero_point = LLONG_MAX; + ctx->_remote_i_size = i_size_read(&ctx->inode); + ctx->_zero_point = LLONG_MAX; ctx->flags = 0; atomic_set(&ctx->io_count, 0); #if IS_ENABLED(CONFIG_FSCACHE) @@ -498,7 +746,7 @@ static inline void netfs_inode_init(struct netfs_inode *ctx, mutex_init(&ctx->wb_lock); /* ->releasepage() drives zero_point */ if (use_zero_point) { - ctx->zero_point = ctx->remote_i_size; + ctx->_zero_point = ctx->_remote_i_size; mapping_set_release_always(ctx->inode.i_mapping); } } @@ -511,13 +759,40 @@ static inline void netfs_inode_init(struct netfs_inode *ctx, * * Inform the netfs lib that a file got resized so that it can adjust its state. */ -static inline void netfs_resize_file(struct netfs_inode *ctx, loff_t new_i_size, +static inline void netfs_resize_file(struct netfs_inode *ictx, + unsigned long long new_i_size, bool changed_on_server) { +#if BITS_PER_LONG==32 && defined(CONFIG_SMP) + struct inode *inode = &ictx->inode; + + preempt_disable(); + write_seqcount_begin(&inode->i_size_seqcount); + if (changed_on_server) + ictx->_remote_i_size = new_i_size; + if (new_i_size < ictx->_zero_point) + ictx->_zero_point = new_i_size; + write_seqcount_end(&inode->i_size_seqcount); + preempt_enable(); +#elif BITS_PER_LONG==32 && defined(CONFIG_PREEMPTION) + preempt_disable(); if (changed_on_server) - ctx->remote_i_size = new_i_size; - if (new_i_size < ctx->zero_point) - ctx->zero_point = new_i_size; + ictx->_remote_i_size = new_i_size; + if (new_i_size < ictx->_zero_point) + ictx->_zero_point = new_i_size; + preempt_enable(); +#else + /* + * Pairs with smp_load_acquire() in netfs_read_remote_i_size and + * netfs_read_zero_point() to ensure changes related to inode size + * (such as page contents) are visible before we see the changed inode + * size. + */ + if (changed_on_server) + smp_store_release(&ictx->_remote_i_size, new_i_size); + if (new_i_size < ictx->_zero_point) + smp_store_release(&ictx->_zero_point, new_i_size); +#endif } /** -- cgit v1.2.3 From 4543a4d737944134a1394afe797622546fbcc98a Mon Sep 17 00:00:00 2001 From: David Howells Date: Tue, 12 May 2026 13:33:43 +0100 Subject: netfs: Fix zeropoint update where i_size > remote_i_size Fix the update of the zero point[*] by netfs_release_folio() when there is uncommitted data in the pagecache beyond the folio being released but the on-server EOF is in this folio (ie. i_size > remote_i_size). The update needs to limit zero_point to remote_i_size, not i_size as i_size is a local phenomenon reflecting updates made locally to the pagecache, not stuff written to the server. remote_i_size tracks the server's i_size. [*] The zero point is the file position from which we can assume that the server will just return zeros, so we can avoid generating reads. Note that netfs_invalidate_folio() probably doesn't need fixing as zero_point should be updated by setattr after truncation or fallocate. Found with: fsx -q -N 1000000 -p 10000 -o 128000 -l 600000 \ /xfstest.test/junk --replay-ops=junk.fsxops using the following as junk.fsxops: truncate 0x0 0x1bbae 0x82864 write 0x3ef2e 0xf9c8 0x1bbae write 0x67e05 0xcb5a 0x4e8f6 mapread 0x57781 0x85b6 0x7495f copy_range 0x5d3d 0x10329 0x54fac 0x7495f write 0x64710 0x1c2b 0x7495f mapread 0x64000 0x1000 0x7495f on cifs with the default cache option. It shows read-gaps on folio 0x64 failing with a short read (ie. it hits EOF) if the FMODE_READ check is commented out in netfs_perform_write(): if (//(file->f_mode & FMODE_READ) || netfs_is_cache_enabled(ctx)) { and no fscache. This was initially found with the generic/522 xfstest. Fixes: cce6bfa6ca0e ("netfs: Fix trimming of streaming-write folios in netfs_inval_folio()") Signed-off-by: David Howells Link: https://patch.msgid.link/20260512123404.719402-7-dhowells@redhat.com cc: Paulo Alcantara cc: Matthew Wilcox cc: netfs@lists.linux.dev cc: linux-fsdevel@vger.kernel.org Signed-off-by: Christian Brauner --- fs/netfs/misc.c | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-) diff --git a/fs/netfs/misc.c b/fs/netfs/misc.c index bad661ff2bec..723571ca1b88 100644 --- a/fs/netfs/misc.c +++ b/fs/netfs/misc.c @@ -307,10 +307,10 @@ bool netfs_release_folio(struct folio *folio, gfp_t gfp) return false; netfs_read_sizes(inode, &i_size, &remote_i_size, &zero_point); - end = umin(folio_next_pos(folio), i_size); + end = folio_next_pos(folio); if (end > zero_point) { spin_lock(&inode->i_lock); - end = umin(folio_next_pos(folio), inode->i_size); + end = umin(end, ctx->_remote_i_size); if (end > ctx->_zero_point) netfs_write_zero_point(inode, end); spin_unlock(&inode->i_lock); -- cgit v1.2.3 From dc7832d05deb4d632e8035e3299e31a3528fa0d0 Mon Sep 17 00:00:00 2001 From: Viacheslav Dubeyko Date: Tue, 12 May 2026 13:33:44 +0100 Subject: netfs: fix VM_BUG_ON_FOLIO() issue in netfs_write_begin() call The multiple runs of generic/013 test-case is capable to reproduce a kernel BUG at mm/filemap.c:1504 with probability of 30%. while true; do sudo ./check generic/013 done [ 9849.452376] page: refcount:3 mapcount:0 mapping:00000000e58ff252 index:0x10781 pfn:0x1c322 [ 9849.452412] memcg:ffff8881a1915800 [ 9849.452417] aops:ceph_aops ino:1000058db9e dentry name(?):"f9XXXXXX" [ 9849.452432] flags: 0x17ffffc0000000(node=0|zone=2|lastcpupid=0x1fffff) [ 9849.452441] raw: 0017ffffc0000000 0000000000000000 dead000000000122 ffff88816110d248 [ 9849.452445] raw: 0000000000010781 0000000000000000 00000003ffffffff ffff8881a1915800 [ 9849.452447] page dumped because: VM_BUG_ON_FOLIO(!folio_test_locked(folio)) [ 9849.452474] ------------[ cut here ]------------ [ 9849.452476] kernel BUG at mm/filemap.c:1504! [ 9849.478635] Oops: invalid opcode: 0000 [#1] SMP KASAN NOPTI [ 9849.481772] CPU: 2 UID: 0 PID: 84223 Comm: fsstress Not tainted 7.0.0-rc1+ #18 PREEMPT(full) [ 9849.482881] Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS 1.17.0-9.fc43 06/1 0/2025 [ 9849.484539] RIP: 0010:folio_unlock+0x85/0xa0 [ 9849.485076] Code: 89 df 31 f6 e8 1c f3 ff ff 48 8b 5d f8 c9 31 c0 31 d2 31 f6 31 ff c3 cc cc cc cc 48 c7 c6 80 6c d9 a7 48 89 df e8 4b b3 10 00 <0f> 0b 48 89 df e8 21 e6 2c 00 eb 9d 0f 1f 40 00 66 66 2e 0f 1f 84 [ 9849.493818] RSP: 0018:ffff8881bb8076b0 EFLAGS: 00010246 [ 9849.495740] RAX: 0000000000000000 RBX: ffffea00070c8980 RCX: 0000000000000000 [ 9849.498678] RDX: 0000000000000000 RSI: 0000000000000000 RDI: 0000000000000000 [ 9849.500559] RBP: ffff8881bb8076b8 R08: 0000000000000000 R09: 0000000000000000 [ 9849.501097] R10: 0000000000000000 R11: 0000000000000000 R12: 0000000010782000 [ 9849.502108] R13: ffff8881935de738 R14: ffff88816110d010 R15: 0000000000001000 [ 9849.502516] FS: 00007e36cbe94740(0000) GS:ffff88824a899000(0000) knlGS:0000000000000000 [ 9849.502996] CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 [ 9849.503810] CR2: 000000c0002b0000 CR3: 000000011bbf6004 CR4: 0000000000772ef0 [ 9849.504459] PKRU: 55555554 [ 9849.504626] Call Trace: [ 9849.505242] [ 9849.505379] netfs_write_begin+0x7c8/0x10a0 [ 9849.505877] ? __kasan_check_read+0x11/0x20 [ 9849.506384] ? __pfx_netfs_write_begin+0x10/0x10 [ 9849.507178] ceph_write_begin+0x8c/0x1c0 [ 9849.507934] generic_perform_write+0x391/0x8f0 [ 9849.508503] ? __pfx_generic_perform_write+0x10/0x10 [ 9849.509062] ? file_update_time_flags+0x19a/0x4b0 [ 9849.509581] ? ceph_get_caps+0x63/0xf0 [ 9849.510259] ? ceph_get_caps+0x63/0xf0 [ 9849.510530] ceph_write_iter+0xe79/0x1ae0 [ 9849.511282] ? __pfx_ceph_write_iter+0x10/0x10 [ 9849.511839] ? lock_acquire+0x1ad/0x310 [ 9849.512334] ? ksys_write+0xf9/0x230 [ 9849.512582] ? lock_is_held_type+0xaa/0x140 [ 9849.513128] vfs_write+0x512/0x1110 [ 9849.513634] ? __fget_files+0x33/0x350 [ 9849.513893] ? __pfx_vfs_write+0x10/0x10 [ 9849.514143] ? mutex_lock_nested+0x1b/0x30 [ 9849.514394] ksys_write+0xf9/0x230 [ 9849.514621] ? __pfx_ksys_write+0x10/0x10 [ 9849.514887] ? do_syscall_64+0x25e/0x1520 [ 9849.515122] ? __kasan_check_read+0x11/0x20 [ 9849.515366] ? trace_hardirqs_on_prepare+0x178/0x1c0 [ 9849.515655] __x64_sys_write+0x72/0xd0 [ 9849.515885] ? trace_hardirqs_on+0x24/0x1c0 [ 9849.516130] x64_sys_call+0x22f/0x2390 [ 9849.516341] do_syscall_64+0x12b/0x1520 [ 9849.516545] ? do_syscall_64+0x27c/0x1520 [ 9849.516783] ? do_syscall_64+0x27c/0x1520 [ 9849.517003] ? lock_release+0x318/0x480 [ 9849.517220] ? __x64_sys_io_getevents+0x143/0x2d0 [ 9849.517479] ? percpu_ref_put_many.constprop.0+0x8f/0x210 [ 9849.517779] ? entry_SYSCALL_64_after_hwframe+0x76/0x7e [ 9849.518073] ? do_syscall_64+0x25e/0x1520 [ 9849.518291] ? __kasan_check_read+0x11/0x20 [ 9849.518519] ? trace_hardirqs_on_prepare+0x178/0x1c0 [ 9849.518799] ? do_syscall_64+0x27c/0x1520 [ 9849.519024] ? local_clock_noinstr+0xf/0x120 [ 9849.519262] ? entry_SYSCALL_64_after_hwframe+0x76/0x7e [ 9849.519544] ? do_syscall_64+0x25e/0x1520 [ 9849.519781] ? __kasan_check_read+0x11/0x20 [ 9849.520008] ? trace_hardirqs_on_prepare+0x178/0x1c0 [ 9849.520273] ? do_syscall_64+0x27c/0x1520 [ 9849.520491] ? trace_hardirqs_on_prepare+0x178/0x1c0 [ 9849.520767] ? irqentry_exit+0x10c/0x6c0 [ 9849.520984] ? trace_hardirqs_off+0x86/0x1b0 [ 9849.521224] ? exc_page_fault+0xab/0x130 [ 9849.521472] entry_SYSCALL_64_after_hwframe+0x76/0x7e [ 9849.521766] RIP: 0033:0x7e36cbd14907 [ 9849.521989] Code: 10 00 f7 d8 64 89 02 48 c7 c0 ff ff ff ff eb b7 0f 1f 00 f3 0f 1e fa 64 8b 04 25 18 00 00 00 85 c0 75 10 b8 01 00 00 00 0f 05 <48> 3d 00 f0 ff ff 77 51 c3 48 83 ec 28 48 89 54 24 18 48 89 74 24 [ 9849.523057] RSP: 002b:00007ffff2d2a968 EFLAGS: 00000246 ORIG_RAX: 0000000000000001 [ 9849.523484] RAX: ffffffffffffffda RBX: 000000000000e549 RCX: 00007e36cbd14907 [ 9849.523885] RDX: 000000000000e549 RSI: 00005bd797ec6370 RDI: 0000000000000004 [ 9849.524277] RBP: 0000000000000004 R08: 0000000000000047 R09: 00005bd797ec6370 [ 9849.524652] R10: 0000000000000078 R11: 0000000000000246 R12: 0000000000000049 [ 9849.525062] R13: 0000000010781a37 R14: 00005bd797ec6370 R15: 0000000000000000 [ 9849.525447] [ 9849.525574] Modules linked in: intel_rapl_msr intel_rapl_common intel_uncore_frequency_common intel_pmc_core pmt_telemetry pmt_discovery pmt_class intel_pmc_ssram_telemetry intel_vsec kvm_intel joydev kvm irqbypass ghash_clmulni_intel aesni_intel input_leds rapl mac_hid psmouse vga16fb serio_raw vgastate floppy i2c_piix4 bochs qemu_fw_cfg i2c_smbus pata_acpi sch_fq_codel rbd msr parport_pc ppdev lp parport efi_pstore [ 9849.529150] ---[ end trace 0000000000000000 ]--- [ 9849.529502] RIP: 0010:folio_unlock+0x85/0xa0 [ 9849.530813] Code: 89 df 31 f6 e8 1c f3 ff ff 48 8b 5d f8 c9 31 c0 31 d2 31 f6 31 ff c3 cc cc cc cc 48 c7 c6 80 6c d9 a7 48 89 df e8 4b b3 10 00 <0f> 0b 48 89 df e8 21 e6 2c 00 eb 9d 0f 1f 40 00 66 66 2e 0f 1f 84 [ 9849.534986] RSP: 0018:ffff8881bb8076b0 EFLAGS: 00010246 [ 9849.536198] RAX: 0000000000000000 RBX: ffffea00070c8980 RCX: 0000000000000000 [ 9849.537718] RDX: 0000000000000000 RSI: 0000000000000000 RDI: 0000000000000000 [ 9849.539321] RBP: ffff8881bb8076b8 R08: 0000000000000000 R09: 0000000000000000 [ 9849.540862] R10: 0000000000000000 R11: 0000000000000000 R12: 0000000010782000 [ 9849.542438] R13: ffff8881935de738 R14: ffff88816110d010 R15: 0000000000001000 [ 9849.543996] FS: 00007e36cbe94740(0000) GS:ffff88824b899000(0000) knlGS:0000000000000000 [ 9849.545854] CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 [ 9849.547092] CR2: 00007e36cb3ff000 CR3: 000000011bbf6006 CR4: 0000000000772ef0 [ 9849.548679] PKRU: 55555554 The race sequence: 1. Read completes -> netfs_read_collection() runs 2. netfs_wake_rreq_flag(rreq, NETFS_RREQ_IN_PROGRESS, ...) 3. netfs_wait_for_read() returns -EFAULT to netfs_write_begin() 4. The netfs_unlock_abandoned_read_pages() unlocks the folio 5. netfs_write_begin() calls folio_unlock(folio) -> VM_BUG_ON_FOLIO() The key reason of the issue that netfs_unlock_abandoned_read_pages() doesn't check the flag NETFS_RREQ_NO_UNLOCK_FOLIO and executes folio_unlock() unconditionally. This patch implements in netfs_unlock_abandoned_read_pages() logic similar to netfs_unlock_read_folio(). Fixes: ee4cdf7ba857 ("netfs: Speed up buffered reading") Signed-off-by: Viacheslav Dubeyko Signed-off-by: David Howells Link: https://patch.msgid.link/20260512123404.719402-8-dhowells@redhat.com Reviewed-by: Paulo Alcantara (Red Hat) cc: netfs@lists.linux.dev cc: linux-fsdevel@vger.kernel.org cc: Ceph Development Signed-off-by: Christian Brauner --- fs/netfs/read_retry.c | 11 +++++++++-- 1 file changed, 9 insertions(+), 2 deletions(-) diff --git a/fs/netfs/read_retry.c b/fs/netfs/read_retry.c index 5ec548b996d6..e10eb5a07332 100644 --- a/fs/netfs/read_retry.c +++ b/fs/netfs/read_retry.c @@ -292,8 +292,15 @@ void netfs_unlock_abandoned_read_pages(struct netfs_io_request *rreq) struct folio *folio = folioq_folio(p, slot); if (folio && !folioq_is_marked2(p, slot)) { - trace_netfs_folio(folio, netfs_folio_trace_abandon); - folio_unlock(folio); + if (folio->index == rreq->no_unlock_folio && + test_bit(NETFS_RREQ_NO_UNLOCK_FOLIO, + &rreq->flags)) { + _debug("no unlock"); + } else { + trace_netfs_folio(folio, + netfs_folio_trace_abandon); + folio_unlock(folio); + } } } } -- cgit v1.2.3 From 7e3d8db899d54af39fafb2eb3392b0cdae9973b5 Mon Sep 17 00:00:00 2001 From: David Howells Date: Tue, 12 May 2026 13:33:45 +0100 Subject: netfs: Fix potential uninitialised var in netfs_extract_user_iter() In netfs_extract_user_iter(), if it's given a zero-length iterator, it will fall through the loop without setting ret, and so the error handling behaviour will be undefined, depending on whether ret happens to be negative. The value of ret then propagates back up the callstack. Fix this by presetting ret to 0. Fixes: 85dd2c8ff368 ("netfs: Add a function to extract a UBUF or IOVEC into a BVEC iterator") Closes: https://sashiko.dev/#/patchset/20260414082004.3756080-1-dhowells%40redhat.com Signed-off-by: David Howells Link: https://patch.msgid.link/20260512123404.719402-9-dhowells@redhat.com cc: Paulo Alcantara cc: Matthew Wilcox cc: netfs@lists.linux.dev cc: linux-fsdevel@vger.kernel.org Signed-off-by: Christian Brauner --- fs/netfs/iterator.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/fs/netfs/iterator.c b/fs/netfs/iterator.c index 154a14bb2d7f..6903028b7162 100644 --- a/fs/netfs/iterator.c +++ b/fs/netfs/iterator.c @@ -43,7 +43,7 @@ ssize_t netfs_extract_user_iter(struct iov_iter *orig, size_t orig_len, unsigned int max_pages; unsigned int npages = 0; unsigned int i; - ssize_t ret; + ssize_t ret = 0; size_t count = orig_len, offset, len; size_t bv_size, pg_size; -- cgit v1.2.3 From 0aad5704c6b4d14007d4eab15883e8524e4310f4 Mon Sep 17 00:00:00 2001 From: Paulo Alcantara Date: Tue, 12 May 2026 13:33:46 +0100 Subject: netfs: fix error handling in netfs_extract_user_iter() In netfs_extract_user_iter(), if iov_iter_extract_pages() failed to extract user pages, bail out on -ENOMEM, otherwise return the error code only if @npages == 0, allowing short DIO reads and writes to be issued. This fixes mmapstress02 from LTP tests against CIFS. Fixes: 85dd2c8ff368 ("netfs: Add a function to extract a UBUF or IOVEC into a BVEC iterator") Reported-by: Xiaoli Feng Signed-off-by: Paulo Alcantara (Red Hat) Signed-off-by: David Howells Link: https://patch.msgid.link/20260512123404.719402-10-dhowells@redhat.com Cc: netfs@lists.linux.dev Cc: stable@vger.kernel.org Cc: linux-cifs@vger.kernel.org Cc: linux-fsdevel@vger.kernel.org Signed-off-by: Christian Brauner --- fs/netfs/iterator.c | 13 ++++++++++--- 1 file changed, 10 insertions(+), 3 deletions(-) diff --git a/fs/netfs/iterator.c b/fs/netfs/iterator.c index 6903028b7162..429e4396e1b0 100644 --- a/fs/netfs/iterator.c +++ b/fs/netfs/iterator.c @@ -22,7 +22,7 @@ * * Extract the page fragments from the given amount of the source iterator and * build up a second iterator that refers to all of those bits. This allows - * the original iterator to disposed of. + * the original iterator to be disposed of. * * @extraction_flags can have ITER_ALLOW_P2PDMA set to request peer-to-peer DMA be * allowed on the pages extracted. @@ -67,8 +67,8 @@ ssize_t netfs_extract_user_iter(struct iov_iter *orig, size_t orig_len, ret = iov_iter_extract_pages(orig, &pages, count, max_pages - npages, extraction_flags, &offset); - if (ret < 0) { - pr_err("Couldn't get user pages (rc=%zd)\n", ret); + if (unlikely(ret <= 0)) { + ret = ret ?: -EIO; break; } @@ -97,6 +97,13 @@ ssize_t netfs_extract_user_iter(struct iov_iter *orig, size_t orig_len, npages += cur_npages; } + if (ret < 0 && (ret == -ENOMEM || npages == 0)) { + for (i = 0; i < npages; i++) + unpin_user_page(bv[i].bv_page); + kvfree(bv); + return ret; + } + iov_iter_bvec(new, orig->data_source, bv, npages, orig_len - count); return npages; } -- cgit v1.2.3 From 0ef37eef83fad3542ee06db2940433ae1a92b39d Mon Sep 17 00:00:00 2001 From: David Howells Date: Tue, 12 May 2026 13:33:47 +0100 Subject: netfs: Fix overrun check in netfs_extract_user_iter() Fix netfs_extract_user_iter() so that if iov_iter_extract_pages() overfills pages[], then those pages don't get included in the iterator constructed at the end of the function. If there was an overfill, memory corruption has already happened. Fixes: 85dd2c8ff368 ("netfs: Add a function to extract a UBUF or IOVEC into a BVEC iterator") Closes: https://sashiko.dev/#/patchset/20260427154639.180684-1-dhowells%40redhat.com Signed-off-by: David Howells Link: https://patch.msgid.link/20260512123404.719402-11-dhowells@redhat.com cc: Paulo Alcantara cc: netfs@lists.linux.dev cc: linux-fsdevel@vger.kernel.org Signed-off-by: Christian Brauner --- fs/netfs/iterator.c | 26 +++++++++++++++++--------- 1 file changed, 17 insertions(+), 9 deletions(-) diff --git a/fs/netfs/iterator.c b/fs/netfs/iterator.c index 429e4396e1b0..b375567e0520 100644 --- a/fs/netfs/iterator.c +++ b/fs/netfs/iterator.c @@ -72,21 +72,24 @@ ssize_t netfs_extract_user_iter(struct iov_iter *orig, size_t orig_len, break; } - if (ret > count) { - pr_err("get_pages rc=%zd more than %zu\n", ret, count); + if (WARN(ret > count, + "%s: extract_pages overrun %zd > %zu bytes\n", + __func__, ret, count)) { + ret = -EIO; break; } - count -= ret; - ret += offset; - cur_npages = DIV_ROUND_UP(ret, PAGE_SIZE); - - if (npages + cur_npages > max_pages) { - pr_err("Out of bvec array capacity (%u vs %u)\n", - npages + cur_npages, max_pages); + cur_npages = DIV_ROUND_UP(offset + ret, PAGE_SIZE); + if (WARN(cur_npages > max_pages - npages, + "%s: extract_pages overrun %u > %u pages\n", + __func__, npages + cur_npages, max_pages)) { + ret = -EIO; break; } + count -= ret; + ret += offset; + for (i = 0; i < cur_npages; i++) { len = ret > PAGE_SIZE ? PAGE_SIZE : ret; bvec_set_page(bv + npages + i, *pages++, len - offset, offset); @@ -97,6 +100,11 @@ ssize_t netfs_extract_user_iter(struct iov_iter *orig, size_t orig_len, npages += cur_npages; } + /* Note: Don't try to clean up after EIO. Either we got no pages, so + * nothing to clean up, or we got a buffer overrun, memory corruption + * and can't trust the stuff in the buffer (a WARN was emitted). + */ + if (ret < 0 && (ret == -ENOMEM || npages == 0)) { for (i = 0; i < npages; i++) unpin_user_page(bv[i].bv_page); -- cgit v1.2.3 From 156ac2ec2ee77c44c4eb7439d6d165247ba12247 Mon Sep 17 00:00:00 2001 From: David Howells Date: Tue, 12 May 2026 13:33:48 +0100 Subject: netfs: Fix netfs_invalidate_folio() to clear dirty bit if all changes gone If a streaming write is made, this will leave the relevant modified folio in a not-uptodate, but dirty state with a netfs_folio struct hung off of folio->private indicating the dirty range. Subsequently truncating the file such that the dirty data in the folio is removed, but the first part of the folio theoretically remains will cause the netfs_folio struct to be discarded... but will leave the dirty flag set. If the folio is then read via mmap(), netfs_read_folio() will see that the page is dirty and jump to netfs_read_gaps() to fill in the missing bits. netfs_read_gaps(), however, expects there to be a netfs_folio struct present and can oops because truncate removed it. Fix this by calling folio_cancel_dirty() in netfs_invalidate_folio() in the event that all the dirty data in the folio is erased (as nfs does). Also add some tracepoints to log modifications to a dirty page. This can be reproduced with something like: dd if=/dev/zero of=/xfstest.test/foo bs=1M count=1 umount /xfstest.test mount /xfstest.test xfs_io -c "w 0xbbbf 0xf96c" \ -c "truncate 0xbbbf" \ -c "mmap -r 0xb000 0x11000" \ -c "mr 0xb000 0x11000" \ /xfstest.test/foo with fscaching disabled (otherwise streaming writes are suppressed) and a change to netfs_perform_write() to disallow streaming writes if the fd is open O_RDWR: if (//(file->f_mode & FMODE_READ) || <--- comment this out netfs_is_cache_enabled(ctx)) { It should be reproducible even without this change, but if prevents the above trivial xfs_io command from reproducing it. Note that the initial dd is important: the file must start out sufficiently large that the zero-point logic doesn't just clear the gaps because it knows there's nothing in the file to read yet. Unmounting and mounting is needed to clear the pagecache (there are other ways to do that that may also work). This was initially reproduced with the generic/522 xfstest on some patches that remove the FMODE_READ restriction. Fixes: 9ebff83e6481 ("netfs: Prep to use folio->private for write grouping and streaming write") Reported-by: Marc Dionne Signed-off-by: David Howells Link: https://patch.msgid.link/20260512123404.719402-12-dhowells@redhat.com cc: Paulo Alcantara cc: Matthew Wilcox cc: netfs@lists.linux.dev cc: linux-fsdevel@vger.kernel.org Signed-off-by: Christian Brauner --- fs/netfs/misc.c | 6 +++++- include/trace/events/netfs.h | 4 ++++ 2 files changed, 9 insertions(+), 1 deletion(-) diff --git a/fs/netfs/misc.c b/fs/netfs/misc.c index 723571ca1b88..24b20e80e9a8 100644 --- a/fs/netfs/misc.c +++ b/fs/netfs/misc.c @@ -263,6 +263,7 @@ void netfs_invalidate_folio(struct folio *folio, size_t offset, size_t length) /* Move the start of the data. */ finfo->dirty_len = fend - iend; finfo->dirty_offset = offset; + trace_netfs_folio(folio, netfs_folio_trace_invalidate_front); return; } @@ -271,12 +272,14 @@ void netfs_invalidate_folio(struct folio *folio, size_t offset, size_t length) */ if (iend >= fend) { finfo->dirty_len = offset - fstart; + trace_netfs_folio(folio, netfs_folio_trace_invalidate_tail); return; } /* A partial write was split. The caller has already zeroed * it, so just absorb the hole. */ + trace_netfs_folio(folio, netfs_folio_trace_invalidate_middle); } return; @@ -284,8 +287,9 @@ erase_completely: netfs_put_group(netfs_folio_group(folio)); folio_detach_private(folio); folio_clear_uptodate(folio); + folio_cancel_dirty(folio); kfree(finfo); - return; + trace_netfs_folio(folio, netfs_folio_trace_invalidate_all); } EXPORT_SYMBOL(netfs_invalidate_folio); diff --git a/include/trace/events/netfs.h b/include/trace/events/netfs.h index 8c936fc575d5..0b702f74aefe 100644 --- a/include/trace/events/netfs.h +++ b/include/trace/events/netfs.h @@ -194,6 +194,10 @@ EM(netfs_folio_trace_copy_to_cache, "mark-copy") \ EM(netfs_folio_trace_end_copy, "end-copy") \ EM(netfs_folio_trace_filled_gaps, "filled-gaps") \ + EM(netfs_folio_trace_invalidate_all, "inval-all") \ + EM(netfs_folio_trace_invalidate_front, "inval-front") \ + EM(netfs_folio_trace_invalidate_middle, "inval-mid") \ + EM(netfs_folio_trace_invalidate_tail, "inval-tail") \ EM(netfs_folio_trace_kill, "kill") \ EM(netfs_folio_trace_kill_cc, "kill-cc") \ EM(netfs_folio_trace_kill_g, "kill-g") \ -- cgit v1.2.3 From daeb443b92817021c1234e8eded219e164b7c35d Mon Sep 17 00:00:00 2001 From: David Howells Date: Tue, 12 May 2026 13:33:49 +0100 Subject: netfs: Defer the emission of trace_netfs_folio() Change netfs_perform_write() to keep the netfs_folio trace value in a variable and emit it later to make it easier to choose the value displayed. This is a prerequisite for a subsequent patch. Closes: https://sashiko.dev/#/patchset/20260414082004.3756080-1-dhowells%40redhat.com Signed-off-by: David Howells Link: https://patch.msgid.link/20260512123404.719402-13-dhowells@redhat.com cc: Paulo Alcantara cc: Matthew Wilcox cc: netfs@lists.linux.dev cc: linux-fsdevel@vger.kernel.org Signed-off-by: Christian Brauner --- fs/netfs/buffered_write.c | 18 ++++++++++-------- 1 file changed, 10 insertions(+), 8 deletions(-) diff --git a/fs/netfs/buffered_write.c b/fs/netfs/buffered_write.c index b6ecd059dc4f..278aeb074e75 100644 --- a/fs/netfs/buffered_write.c +++ b/fs/netfs/buffered_write.c @@ -149,6 +149,7 @@ ssize_t netfs_perform_write(struct kiocb *iocb, struct iov_iter *iter, } do { + enum netfs_folio_trace trace; struct netfs_folio *finfo; struct netfs_group *group; unsigned long long fpos; @@ -222,7 +223,7 @@ ssize_t netfs_perform_write(struct kiocb *iocb, struct iov_iter *iter, if (unlikely(copied == 0)) goto copy_failed; netfs_set_group(folio, netfs_group); - trace_netfs_folio(folio, netfs_folio_is_uptodate); + trace = netfs_folio_is_uptodate; goto copied; } @@ -238,7 +239,7 @@ ssize_t netfs_perform_write(struct kiocb *iocb, struct iov_iter *iter, folio_zero_segment(folio, offset + copied, flen); __netfs_set_group(folio, netfs_group); folio_mark_uptodate(folio); - trace_netfs_folio(folio, netfs_modify_and_clear); + trace = netfs_modify_and_clear; goto copied; } @@ -256,7 +257,7 @@ ssize_t netfs_perform_write(struct kiocb *iocb, struct iov_iter *iter, } __netfs_set_group(folio, netfs_group); folio_mark_uptodate(folio); - trace_netfs_folio(folio, netfs_whole_folio_modify); + trace = netfs_whole_folio_modify; goto copied; } @@ -283,7 +284,7 @@ ssize_t netfs_perform_write(struct kiocb *iocb, struct iov_iter *iter, if (unlikely(copied == 0)) goto copy_failed; netfs_set_group(folio, netfs_group); - trace_netfs_folio(folio, netfs_just_prefetch); + trace = netfs_just_prefetch; goto copied; } @@ -297,7 +298,7 @@ ssize_t netfs_perform_write(struct kiocb *iocb, struct iov_iter *iter, if (offset == 0 && copied == flen) { __netfs_set_group(folio, netfs_group); folio_mark_uptodate(folio); - trace_netfs_folio(folio, netfs_streaming_filled_page); + trace = netfs_streaming_filled_page; goto copied; } @@ -312,7 +313,7 @@ ssize_t netfs_perform_write(struct kiocb *iocb, struct iov_iter *iter, finfo->dirty_len = copied; folio_attach_private(folio, (void *)((unsigned long)finfo | NETFS_FOLIO_INFO)); - trace_netfs_folio(folio, netfs_streaming_write); + trace = netfs_streaming_write; goto copied; } @@ -332,9 +333,9 @@ ssize_t netfs_perform_write(struct kiocb *iocb, struct iov_iter *iter, folio_detach_private(folio); folio_mark_uptodate(folio); kfree(finfo); - trace_netfs_folio(folio, netfs_streaming_cont_filled_page); + trace = netfs_streaming_cont_filled_page; } else { - trace_netfs_folio(folio, netfs_streaming_write_cont); + trace = netfs_streaming_write_cont; } goto copied; } @@ -350,6 +351,7 @@ ssize_t netfs_perform_write(struct kiocb *iocb, struct iov_iter *iter, continue; copied: + trace_netfs_folio(folio, trace); flush_dcache_folio(folio); /* Update the inode size if we moved the EOF marker */ -- cgit v1.2.3 From 7b4dcf1b9455a6e52ac7478b4057dbe10359576d Mon Sep 17 00:00:00 2001 From: David Howells Date: Tue, 12 May 2026 13:33:50 +0100 Subject: netfs: Fix streaming write being overwritten In order to avoid reading whilst writing, netfslib will allow "streaming writes" in which dirty data is stored directly into folios without reading them first. Such folios are marked dirty but may not be marked uptodate. If a folio is entirely written by a streaming write, uptodate will be set, otherwise it will have a netfs_folio struct attached to ->private recording the dirty region. In the event that a partially written streaming write page is to be overwritten entirely by a single write(), netfs_perform_write() will try to copy over it, but doesn't discard the netfs_folio if it succeeds; further, it doesn't correctly handle a partial copy that overwrites some of the dirty data. Fix this by the following: (1) If the folio is successfully overwritten, free the netfs_folio struct before marking the page uptodate. (2) If the copy to the folio partially fails, but short of the dirty data, just ignore the copy. (3) If the copy partially fails and overwrites some of the dirty data, accept the copy, update the netfs_folio struct to record the new data. If the folio is now filled, free the netfs_folio and set uptodate, otherwise return a partial write. Found with: fsx -q -N 1000000 -p 10000 -o 128000 -l 600000 \ /xfstest.test/junk --replay-ops=junk.fsxops using the following as junk.fsxops: truncate 0x0 0 0x927c0 write 0x63fb8 0x53c8 0 copy_range 0xb704 0x19b9 0x24429 0x79380 write 0x2402b 0x144a2 0x90660 * write 0x204d5 0x140a0 0x927c0 * copy_range 0x1f72c 0x137d0 0x7a906 0x927c0 * read 0x00000 0x20000 0x9157c read 0x20000 0x20000 0x9157c read 0x40000 0x20000 0x9157c read 0x60000 0x20000 0x9157c read 0x7e1a0 0xcfb9 0x9157c on cifs with the default cache option. It shows folio 0x24 misbehaving if the FMODE_READ check is commented out in netfs_perform_write(): if (//(file->f_mode & FMODE_READ) || netfs_is_cache_enabled(ctx)) { and no fscache. This was initially found with the generic/522 xfstest. Fixes: 8f52de0077ba ("netfs: Reduce number of conditional branches in netfs_perform_write()") Signed-off-by: David Howells Link: https://patch.msgid.link/20260512123404.719402-14-dhowells@redhat.com cc: Paulo Alcantara cc: Matthew Wilcox cc: netfs@lists.linux.dev cc: linux-fsdevel@vger.kernel.org Signed-off-by: Christian Brauner --- fs/netfs/buffered_write.c | 47 ++++++++++++++++++++++++++++++++------------ include/trace/events/netfs.h | 3 +++ 2 files changed, 37 insertions(+), 13 deletions(-) diff --git a/fs/netfs/buffered_write.c b/fs/netfs/buffered_write.c index 278aeb074e75..991552724868 100644 --- a/fs/netfs/buffered_write.c +++ b/fs/netfs/buffered_write.c @@ -246,18 +246,38 @@ ssize_t netfs_perform_write(struct kiocb *iocb, struct iov_iter *iter, /* See if we can write a whole folio in one go. */ if (!maybe_trouble && offset == 0 && part >= flen) { copied = copy_folio_from_iter_atomic(folio, offset, part, iter); - if (unlikely(copied == 0)) + if (likely(copied == part)) { + if (finfo) { + trace = netfs_whole_folio_modify_filled; + goto folio_now_filled; + } + __netfs_set_group(folio, netfs_group); + folio_mark_uptodate(folio); + trace = netfs_whole_folio_modify; + goto copied; + } + if (copied == 0) goto copy_failed; - if (unlikely(copied < part)) { + if (!finfo || copied <= finfo->dirty_offset) { maybe_trouble = true; iov_iter_revert(iter, copied); copied = 0; folio_unlock(folio); goto retry; } - __netfs_set_group(folio, netfs_group); - folio_mark_uptodate(folio); - trace = netfs_whole_folio_modify; + + /* We overwrote some existing dirty data, so we have to + * accept the partial write. + */ + finfo->dirty_len += finfo->dirty_offset; + if (finfo->dirty_len == flen) { + trace = netfs_whole_folio_modify_filled_efault; + goto folio_now_filled; + } + if (copied > finfo->dirty_len) + finfo->dirty_len = copied; + finfo->dirty_offset = 0; + trace = netfs_whole_folio_modify_efault; goto copied; } @@ -327,16 +347,10 @@ ssize_t netfs_perform_write(struct kiocb *iocb, struct iov_iter *iter, goto copy_failed; finfo->dirty_len += copied; if (finfo->dirty_offset == 0 && finfo->dirty_len == flen) { - if (finfo->netfs_group) - folio_change_private(folio, finfo->netfs_group); - else - folio_detach_private(folio); - folio_mark_uptodate(folio); - kfree(finfo); trace = netfs_streaming_cont_filled_page; - } else { - trace = netfs_streaming_write_cont; + goto folio_now_filled; } + trace = netfs_streaming_write_cont; goto copied; } @@ -350,6 +364,13 @@ ssize_t netfs_perform_write(struct kiocb *iocb, struct iov_iter *iter, goto out; continue; + folio_now_filled: + if (finfo->netfs_group) + folio_change_private(folio, finfo->netfs_group); + else + folio_detach_private(folio); + folio_mark_uptodate(folio); + kfree(finfo); copied: trace_netfs_folio(folio, trace); flush_dcache_folio(folio); diff --git a/include/trace/events/netfs.h b/include/trace/events/netfs.h index 0b702f74aefe..aa9940ba307b 100644 --- a/include/trace/events/netfs.h +++ b/include/trace/events/netfs.h @@ -177,6 +177,9 @@ EM(netfs_folio_is_uptodate, "mod-uptodate") \ EM(netfs_just_prefetch, "mod-prefetch") \ EM(netfs_whole_folio_modify, "mod-whole-f") \ + EM(netfs_whole_folio_modify_efault, "mod-whole-f!") \ + EM(netfs_whole_folio_modify_filled, "mod-whole-f+") \ + EM(netfs_whole_folio_modify_filled_efault, "mod-whole-f+!") \ EM(netfs_modify_and_clear, "mod-n-clear") \ EM(netfs_streaming_write, "mod-streamw") \ EM(netfs_streaming_write_cont, "mod-streamw+") \ -- cgit v1.2.3 From b6a4ae1634b3ad2aaa05222e53d36da532852faf Mon Sep 17 00:00:00 2001 From: David Howells Date: Tue, 12 May 2026 13:33:51 +0100 Subject: netfs: Fix potential deadlock in write-through mode Fix netfs_advance_writethrough() to always unlock the supplied folio and to mark it dirty if it isn't yet written to the end. Unfortunately, it can't be marked for writeback until the folio is done with as that may cause a deadlock against mmapped reads and writes. Even though it has been marked dirty, premature writeback can't occur as the caller is holding both inode->i_rwsem (which will prevent concurrent truncation, fallocation, DIO and other writes) and ictx->wb_lock (which will cause flushing to wait and writeback to skip or wait). Note that this may be easier to deal with once the queuing of folios is split from the generation of subrequests. Fixes: 288ace2f57c9 ("netfs: New writeback implementation") Closes: https://sashiko.dev/#/patchset/20260427154639.180684-1-dhowells%40redhat.com Signed-off-by: David Howells Link: https://patch.msgid.link/20260512123404.719402-15-dhowells@redhat.com cc: Paulo Alcantara cc: netfs@lists.linux.dev cc: linux-fsdevel@vger.kernel.org Signed-off-by: Christian Brauner --- fs/netfs/write_issue.c | 39 +++++++++++++++++++++++++-------------- 1 file changed, 25 insertions(+), 14 deletions(-) diff --git a/fs/netfs/write_issue.c b/fs/netfs/write_issue.c index b0e9690bb90c..03961622996b 100644 --- a/fs/netfs/write_issue.c +++ b/fs/netfs/write_issue.c @@ -414,12 +414,7 @@ static int netfs_write_folio(struct netfs_io_request *wreq, if (streamw) netfs_issue_write(wreq, cache); - /* Flip the page to the writeback state and unlock. If we're called - * from write-through, then the page has already been put into the wb - * state. - */ - if (wreq->origin == NETFS_WRITEBACK) - folio_start_writeback(folio); + folio_start_writeback(folio); folio_unlock(folio); if (fgroup == NETFS_FOLIO_COPY_TO_CACHE) { @@ -647,29 +642,41 @@ int netfs_advance_writethrough(struct netfs_io_request *wreq, struct writeback_c struct folio *folio, size_t copied, bool to_page_end, struct folio **writethrough_cache) { + int ret; + _enter("R=%x ic=%zu ws=%u cp=%zu tp=%u", wreq->debug_id, wreq->buffer.iter.count, wreq->wsize, copied, to_page_end); - if (!*writethrough_cache) { - if (folio_test_dirty(folio)) - /* Sigh. mmap. */ - folio_clear_dirty_for_io(folio); + /* The folio is locked. */ + if (*writethrough_cache != folio) { + if (*writethrough_cache) { + /* Did the folio get moved? */ + folio_put(*writethrough_cache); + *writethrough_cache = NULL; + } /* We can make multiple writes to the folio... */ - folio_start_writeback(folio); if (wreq->len == 0) trace_netfs_folio(folio, netfs_folio_trace_wthru); else trace_netfs_folio(folio, netfs_folio_trace_wthru_plus); *writethrough_cache = folio; + folio_get(folio); } wreq->len += copied; - if (!to_page_end) + + if (!to_page_end) { + folio_mark_dirty(folio); + folio_unlock(folio); return 0; + } + ret = netfs_write_folio(wreq, wbc, folio); + folio_put(*writethrough_cache); *writethrough_cache = NULL; - return netfs_write_folio(wreq, wbc, folio); + wreq->submitted = wreq->len; + return ret; } /* @@ -683,8 +690,12 @@ ssize_t netfs_end_writethrough(struct netfs_io_request *wreq, struct writeback_c _enter("R=%x", wreq->debug_id); - if (writethrough_cache) + if (writethrough_cache) { + folio_lock(writethrough_cache); netfs_write_folio(wreq, wbc, writethrough_cache); + folio_put(writethrough_cache); + wreq->submitted = wreq->len; + } netfs_end_issue_write(wreq); -- cgit v1.2.3 From a41168aef634356a9b87ec44349e3c82835700a5 Mon Sep 17 00:00:00 2001 From: David Howells Date: Tue, 12 May 2026 13:33:52 +0100 Subject: netfs: Fix read-gaps to remove netfs_folio from filled folio Fix netfs_read_gaps() to remove the netfs_folio record from the folio record before marking the folio uptodate if it successfully fills the gaps around the dirty data in a streaming write folio (dirty, but not uptodate). Found with: fsx -q -N 1000000 -p 10000 -o 128000 -l 600000 \ /xfstest.test/junk --replay-ops=junk.fsxops using the following as junk.fsxops: truncate 0x0 0x138b1 0x8b15d * write 0x507ee 0x10df7 0x927c0 write 0x19993 0x10e04 0x927c0 * mapwrite 0x66214 0x1a253 0x927c0 copy_range 0xb704 0x89b9 0x24429 0x79380 write 0x2402b 0x144a2 0x90660 * mapwrite 0x204d5 0x140a0 0x927c0 * copy_range 0x1f72c 0x137d0 0x7a906 0x927c0 * read 0 0x9157c 0x9157c on cifs with the default cache option. It shows folio 0x24 misbehaving if the FMODE_READ check is commented out in netfs_perform_write(): if (//(file->f_mode & FMODE_READ) || netfs_is_cache_enabled(ctx)) { and no fscache. This was initially found with the generic/522 xfstest. Signed-off-by: David Howells Link: https://patch.msgid.link/20260512123404.719402-16-dhowells@redhat.com Fixes: ee4cdf7ba857 ("netfs: Speed up buffered reading") cc: Paulo Alcantara cc: Matthew Wilcox cc: netfs@lists.linux.dev cc: linux-fsdevel@vger.kernel.org Signed-off-by: Christian Brauner --- fs/netfs/buffered_read.c | 11 ++++++++--- 1 file changed, 8 insertions(+), 3 deletions(-) diff --git a/fs/netfs/buffered_read.c b/fs/netfs/buffered_read.c index ebd84a6cc3f0..51f844bfbdff 100644 --- a/fs/netfs/buffered_read.c +++ b/fs/netfs/buffered_read.c @@ -395,6 +395,7 @@ static int netfs_read_gaps(struct file *file, struct folio *folio) { struct netfs_io_request *rreq; struct address_space *mapping = folio->mapping; + struct netfs_group *group = netfs_folio_group(folio); struct netfs_folio *finfo = netfs_folio_info(folio); struct netfs_inode *ctx = netfs_inode(mapping->host); struct folio *sink = NULL; @@ -461,6 +462,12 @@ static int netfs_read_gaps(struct file *file, struct folio *folio) ret = netfs_wait_for_read(rreq); if (ret >= 0) { + if (group) + folio_change_private(folio, group); + else + folio_detach_private(folio); + kfree(finfo); + trace_netfs_folio(folio, netfs_folio_trace_filled_gaps); flush_dcache_folio(folio); folio_mark_uptodate(folio); } @@ -496,10 +503,8 @@ int netfs_read_folio(struct file *file, struct folio *folio) struct netfs_inode *ctx = netfs_inode(mapping->host); int ret; - if (folio_test_dirty(folio)) { - trace_netfs_folio(folio, netfs_folio_trace_read_gaps); + if (folio_test_dirty(folio)) return netfs_read_gaps(file, folio); - } _enter("%lx", folio->index); -- cgit v1.2.3 From 70a7b9193bbbfceaab5974de66834c64ccc875dd Mon Sep 17 00:00:00 2001 From: David Howells Date: Tue, 12 May 2026 13:33:53 +0100 Subject: netfs: Fix write streaming disablement if fd open O_RDWR In netfs_perform_write(), "write streaming" (the caching of dirty data in dirty but !uptodate folios) is performed to avoid the need to read data that is just going to get immediately overwritten. However, this is/will be disabled in three circumstances: if the fd is open O_RDWR, if fscache is in use (as we need to round out the blocks for DIO) or if content encryption is enabled (again for rounding out purposes). The idea behind disabling it if the fd is open O_RDWR is that we'd need to flush the write-streaming page before we could read the data, particularly through mmap. But netfs now fills in the gaps if ->read_folio() is called on the page, so that is unnecessary. Further, this doesn't actually work if a separate fd is open for reading. Fix this by removing the check for O_RDWR, thereby allowing streaming writes even when we might read. This caused a number of problems with the generic/522 xfstest, but those are now fixed. Fixes: c38f4e96e605 ("netfs: Provide func to copy data to pagecache for buffered write") Signed-off-by: David Howells Link: https://patch.msgid.link/20260512123404.719402-17-dhowells@redhat.com cc: Paulo Alcantara cc: Matthew Wilcox cc: netfs@lists.linux.dev cc: linux-fsdevel@vger.kernel.org Signed-off-by: Christian Brauner --- fs/netfs/buffered_write.c | 17 +++++++---------- 1 file changed, 7 insertions(+), 10 deletions(-) diff --git a/fs/netfs/buffered_write.c b/fs/netfs/buffered_write.c index 991552724868..f79fb5996540 100644 --- a/fs/netfs/buffered_write.c +++ b/fs/netfs/buffered_write.c @@ -203,11 +203,11 @@ ssize_t netfs_perform_write(struct kiocb *iocb, struct iov_iter *iter, } /* Decide how we should modify a folio. We might be attempting - * to do write-streaming, in which case we don't want to a - * local RMW cycle if we can avoid it. If we're doing local - * caching or content crypto, we award that priority over - * avoiding RMW. If the file is open readably, then we also - * assume that we may want to read what we wrote. + * to do write-streaming, as we don't want to a local RMW cycle + * if we can avoid it. If we're doing local caching or content + * crypto, we award that priority over avoiding RMW. If the + * file is open readably, then we let ->read_folio() fill in + * the gaps. */ finfo = netfs_folio_info(folio); group = netfs_folio_group(folio); @@ -283,12 +283,9 @@ ssize_t netfs_perform_write(struct kiocb *iocb, struct iov_iter *iter, /* We don't want to do a streaming write on a file that loses * caching service temporarily because the backing store got - * culled and we don't really want to get a streaming write on - * a file that's open for reading as ->read_folio() then has to - * be able to flush it. + * culled. */ - if ((file->f_mode & FMODE_READ) || - netfs_is_cache_enabled(ctx)) { + if (netfs_is_cache_enabled(ctx)) { if (finfo) { netfs_stat(&netfs_n_wh_wstream_conflict); goto flush_content; -- cgit v1.2.3 From 3e5dd91b87a8b1450217b56a336bee315f40da7d Mon Sep 17 00:00:00 2001 From: David Howells Date: Tue, 12 May 2026 13:33:54 +0100 Subject: netfs: Fix early put of sink folio in netfs_read_gaps() Fix netfs_read_gaps() to release the sink page it uses after waiting for the request to complete. The way the sink page is used is that an ITER_BVEC-class iterator is created that has the gaps from the target folio at either end, but has the sink page tiled over the middle so that a single read op can fill in both gaps. The bug was found by KASAN detecting a UAF on the generic/075 xfstest in the cifsd kernel thread that handles reception of data from the TCP socket: BUG: KASAN: use-after-free in _copy_to_iter+0x48a/0xa20 Write of size 885 at addr ffff888107f92000 by task cifsd/1285 CPU: 2 UID: 0 PID: 1285 Comm: cifsd Not tainted 7.0.0 #6 PREEMPT(lazy) Call Trace: dump_stack_lvl+0x5d/0x80 print_report+0x17f/0x4f1 kasan_report+0x100/0x1e0 kasan_check_range+0x10f/0x1e0 __asan_memcpy+0x3c/0x60 _copy_to_iter+0x48a/0xa20 __skb_datagram_iter+0x2c9/0x430 skb_copy_datagram_iter+0x6e/0x160 tcp_recvmsg_locked+0xce0/0x1130 tcp_recvmsg+0xeb/0x300 inet_recvmsg+0xcf/0x3a0 sock_recvmsg+0xea/0x100 cifs_readv_from_socket+0x3a6/0x4d0 [cifs] cifs_read_iter_from_socket+0xdd/0x130 [cifs] cifs_readv_receive+0xaad/0xb10 [cifs] cifs_demultiplex_thread+0x1148/0x1740 [cifs] kthread+0x1cf/0x210 Fixes: ee4cdf7ba857 ("netfs: Speed up buffered reading") Reported-by: Steve French Signed-off-by: David Howells Link: https://patch.msgid.link/20260512123404.719402-18-dhowells@redhat.com Reviewed-by: Paulo Alcantara (Red Hat) cc: Paulo Alcantara cc: Matthew Wilcox cc: netfs@lists.linux.dev cc: linux-fsdevel@vger.kernel.org Signed-off-by: Christian Brauner --- fs/netfs/buffered_read.c | 6 +++--- 1 file changed, 3 insertions(+), 3 deletions(-) diff --git a/fs/netfs/buffered_read.c b/fs/netfs/buffered_read.c index 51f844bfbdff..e7ad511e494c 100644 --- a/fs/netfs/buffered_read.c +++ b/fs/netfs/buffered_read.c @@ -457,9 +457,6 @@ static int netfs_read_gaps(struct file *file, struct folio *folio) netfs_read_to_pagecache(rreq, NULL); - if (sink) - folio_put(sink); - ret = netfs_wait_for_read(rreq); if (ret >= 0) { if (group) @@ -471,6 +468,9 @@ static int netfs_read_gaps(struct file *file, struct folio *folio) flush_dcache_folio(folio); folio_mark_uptodate(folio); } + + if (sink) + folio_put(sink); folio_unlock(folio); netfs_put_request(rreq, netfs_rreq_trace_put_return); return ret < 0 ? ret : 0; -- cgit v1.2.3 From 5046a34f0643441f05b0253ea64e1a3af87efe14 Mon Sep 17 00:00:00 2001 From: David Howells Date: Tue, 12 May 2026 13:33:55 +0100 Subject: netfs: Fix leak of request in netfs_write_begin() error handling Fix netfs_write_begin() to not leak our ref on the request in the event that we get an error from netfs_wait_for_read(). Fixes: 4090b31422a6 ("netfs: Add a function to consolidate beginning a read") Closes: https://sashiko.dev/#/patchset/20260414082004.3756080-1-dhowells%40redhat.com Signed-off-by: David Howells Link: https://patch.msgid.link/20260512123404.719402-19-dhowells@redhat.com cc: Paulo Alcantara cc: Matthew Wilcox cc: netfs@lists.linux.dev cc: linux-fsdevel@vger.kernel.org Signed-off-by: Christian Brauner --- fs/netfs/buffered_read.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/fs/netfs/buffered_read.c b/fs/netfs/buffered_read.c index e7ad511e494c..004d426c02b4 100644 --- a/fs/netfs/buffered_read.c +++ b/fs/netfs/buffered_read.c @@ -687,9 +687,9 @@ retry: netfs_read_to_pagecache(rreq, NULL); ret = netfs_wait_for_read(rreq); + netfs_put_request(rreq, netfs_rreq_trace_put_return); if (ret < 0) goto error; - netfs_put_request(rreq, netfs_rreq_trace_put_return); have_folio: ret = folio_wait_private_2_killable(folio); -- cgit v1.2.3 From dbe556972100fabb8e5a1b3d2163831ff07b1e8e Mon Sep 17 00:00:00 2001 From: David Howells Date: Tue, 12 May 2026 13:33:56 +0100 Subject: netfs: Fix potential UAF in netfs_unlock_abandoned_read_pages() netfs_unlock_abandoned_read_pages(rreq) accesses the index of the folios it is wanting to unlock and compares that to rreq->no_unlock_folio so that it doesn't unlock a folio being read for netfs_perform_write() or netfs_write_begin(). However, given that netfs_unlock_abandoned_read_pages() is called _after_ NETFS_RREQ_IN_PROGRESS is cleared, the one folio that it's not allowed to dereference is the one specified by ->no_unlock_folio as ownership immediately reverts to the caller. Fix this by storing the folio pointer instead and using that rather than the index. Also fix netfs_unlock_read_folio() where the same applies. Fixes: ee4cdf7ba857 ("netfs: Speed up buffered reading") Closes: https://sashiko.dev/#/patchset/20260414082004.3756080-1-dhowells%40redhat.com Signed-off-by: David Howells Link: https://patch.msgid.link/20260512123404.719402-20-dhowells@redhat.com cc: Paulo Alcantara cc: Viacheslav Dubeyko cc: Matthew Wilcox cc: netfs@lists.linux.dev cc: linux-fsdevel@vger.kernel.org Signed-off-by: Christian Brauner --- fs/netfs/buffered_read.c | 4 ++-- fs/netfs/read_collect.c | 2 +- fs/netfs/read_retry.c | 2 +- include/linux/netfs.h | 2 +- 4 files changed, 5 insertions(+), 5 deletions(-) diff --git a/fs/netfs/buffered_read.c b/fs/netfs/buffered_read.c index 004d426c02b4..83d0b8153e96 100644 --- a/fs/netfs/buffered_read.c +++ b/fs/netfs/buffered_read.c @@ -670,7 +670,7 @@ retry: ret = PTR_ERR(rreq); goto error; } - rreq->no_unlock_folio = folio->index; + rreq->no_unlock_folio = folio; __set_bit(NETFS_RREQ_NO_UNLOCK_FOLIO, &rreq->flags); ret = netfs_begin_cache_read(rreq, ctx); @@ -736,7 +736,7 @@ int netfs_prefetch_for_write(struct file *file, struct folio *folio, goto error; } - rreq->no_unlock_folio = folio->index; + rreq->no_unlock_folio = folio; __set_bit(NETFS_RREQ_NO_UNLOCK_FOLIO, &rreq->flags); ret = netfs_begin_cache_read(rreq, ctx); if (ret == -ENOMEM || ret == -EINTR || ret == -ERESTARTSYS) diff --git a/fs/netfs/read_collect.c b/fs/netfs/read_collect.c index 3c9b847885c2..23660a590124 100644 --- a/fs/netfs/read_collect.c +++ b/fs/netfs/read_collect.c @@ -83,7 +83,7 @@ static void netfs_unlock_read_folio(struct netfs_io_request *rreq, } just_unlock: - if (folio->index == rreq->no_unlock_folio && + if (folio == rreq->no_unlock_folio && test_bit(NETFS_RREQ_NO_UNLOCK_FOLIO, &rreq->flags)) { _debug("no unlock"); } else { diff --git a/fs/netfs/read_retry.c b/fs/netfs/read_retry.c index e10eb5a07332..f59a70f3a086 100644 --- a/fs/netfs/read_retry.c +++ b/fs/netfs/read_retry.c @@ -292,7 +292,7 @@ void netfs_unlock_abandoned_read_pages(struct netfs_io_request *rreq) struct folio *folio = folioq_folio(p, slot); if (folio && !folioq_is_marked2(p, slot)) { - if (folio->index == rreq->no_unlock_folio && + if (folio == rreq->no_unlock_folio && test_bit(NETFS_RREQ_NO_UNLOCK_FOLIO, &rreq->flags)) { _debug("no unlock"); diff --git a/include/linux/netfs.h b/include/linux/netfs.h index 4fd1d796ad73..243c0f737938 100644 --- a/include/linux/netfs.h +++ b/include/linux/netfs.h @@ -252,7 +252,7 @@ struct netfs_io_request { unsigned long long collected_to; /* Point we've collected to */ unsigned long long cleaned_to; /* Position we've cleaned folios to */ unsigned long long abandon_to; /* Position to abandon folios to */ - pgoff_t no_unlock_folio; /* Don't unlock this folio after read */ + const struct folio *no_unlock_folio; /* Don't unlock this folio after read */ unsigned int direct_bv_count; /* Number of elements in direct_bv[] */ unsigned int debug_id; unsigned int rsize; /* Maximum read size (0 for none) */ -- cgit v1.2.3 From 6d91acc7fb85d33ea58fca9b964a32a453937f4b Mon Sep 17 00:00:00 2001 From: David Howells Date: Tue, 12 May 2026 13:33:57 +0100 Subject: netfs: Fix partial invalidation of streaming-write folio In netfs_invalidate_folio(), if the region of a partial invalidation overlaps the front (but not all) of a dirty write cached in a streaming write page (dirty, but not uptodate, with the dirty region tracked by a netfs_folio struct), the function modifies the dirty region - but incorrectly as it moves the region forward by setting the start to the start, not the end, of the invalidation region. Fix this by setting finfo->dirty_offset to the end of the invalidation region (iend). Fixes: cce6bfa6ca0e ("netfs: Fix trimming of streaming-write folios in netfs_inval_folio()") Closes: https://sashiko.dev/#/patchset/20260414082004.3756080-1-dhowells%40redhat.com Signed-off-by: David Howells Link: https://patch.msgid.link/20260512123404.719402-21-dhowells@redhat.com cc: Paulo Alcantara cc: Matthew Wilcox cc: netfs@lists.linux.dev cc: linux-fsdevel@vger.kernel.org Signed-off-by: Christian Brauner --- fs/netfs/misc.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/fs/netfs/misc.c b/fs/netfs/misc.c index 24b20e80e9a8..5d554512ed23 100644 --- a/fs/netfs/misc.c +++ b/fs/netfs/misc.c @@ -262,7 +262,7 @@ void netfs_invalidate_folio(struct folio *folio, size_t offset, size_t length) goto erase_completely; /* Move the start of the data. */ finfo->dirty_len = fend - iend; - finfo->dirty_offset = offset; + finfo->dirty_offset = iend; trace_netfs_folio(folio, netfs_folio_trace_invalidate_front); return; } -- cgit v1.2.3 From ccde2ac757c713535b224233a296de40efe5212d Mon Sep 17 00:00:00 2001 From: David Howells Date: Tue, 12 May 2026 13:33:58 +0100 Subject: netfs: Fix folio->private handling in netfs_perform_write() Under some circumstances, netfs_perform_write() doesn't correctly manipulate folio->private between NULL, NETFS_FOLIO_COPY_TO_CACHE, pointing to a group and pointing to a netfs_folio struct, leading to potential multiple attachments of private data with associated folio ref leaks and also leaks of netfs_folio structs or netfs_group refs. Fix this by consolidating the place at which a folio is marked uptodate in one place and having that look at what's attached to folio->private and decide how to clean it up and then set the new group. Also, the content shouldn't be flushed if group is NULL, even if a group is specified in the netfs_group parameter, as that would be the case for a new folio. A filesystem should always specify netfs_group or never specify netfs_group. The Sashiko auto-review tool noted that it was theoretically possible that the fpos >= ctx->zero_point section might leak if it modified a streaming write folio. This is unlikely, but with a network filesystem, third party changes can happen. It also pointed out that __netfs_set_group() would leak if called multiple times on the same folio from the "whole folio modify section". Fixes: 8f52de0077ba ("netfs: Reduce number of conditional branches in netfs_perform_write()") Closes: https://sashiko.dev/#/patchset/20260414082004.3756080-1-dhowells%40redhat.com Signed-off-by: David Howells Link: https://patch.msgid.link/20260512123404.719402-22-dhowells@redhat.com cc: Paulo Alcantara cc: Matthew Wilcox cc: netfs@lists.linux.dev cc: linux-fsdevel@vger.kernel.org Signed-off-by: Christian Brauner --- fs/netfs/buffered_write.c | 134 ++++++++++++++++++++++++++----------------- include/trace/events/netfs.h | 1 + 2 files changed, 82 insertions(+), 53 deletions(-) diff --git a/fs/netfs/buffered_write.c b/fs/netfs/buffered_write.c index f79fb5996540..6bde3320bcec 100644 --- a/fs/netfs/buffered_write.c +++ b/fs/netfs/buffered_write.c @@ -12,24 +12,6 @@ #include #include "internal.h" -static void __netfs_set_group(struct folio *folio, struct netfs_group *netfs_group) -{ - if (netfs_group) - folio_attach_private(folio, netfs_get_group(netfs_group)); -} - -static void netfs_set_group(struct folio *folio, struct netfs_group *netfs_group) -{ - void *priv = folio_get_private(folio); - - if (unlikely(priv != netfs_group)) { - if (netfs_group && (!priv || priv == NETFS_FOLIO_COPY_TO_CACHE)) - folio_attach_private(folio, netfs_get_group(netfs_group)); - else if (!netfs_group && priv == NETFS_FOLIO_COPY_TO_CACHE) - folio_detach_private(folio); - } -} - /* * Grab a folio for writing and lock it. Attempt to allocate as large a folio * as possible to hold as much of the remaining length as possible in one go. @@ -157,6 +139,7 @@ ssize_t netfs_perform_write(struct kiocb *iocb, struct iov_iter *iter, size_t offset; /* Offset into pagecache folio */ size_t part; /* Bytes to write to folio */ size_t copied; /* Bytes copied from user */ + void *priv; offset = pos & (max_chunk - 1); part = min(max_chunk - offset, iov_iter_count(iter)); @@ -202,6 +185,25 @@ ssize_t netfs_perform_write(struct kiocb *iocb, struct iov_iter *iter, goto error_folio_unlock; } + finfo = netfs_folio_info(folio); + group = netfs_folio_group(folio); + + /* If the requested group differs from the group set on the + * page, then we need to flush out the folio if it has a group + * set (ie. is non-NULL). Note that COPY_TO_CACHE is a special + * case, being a netfs annotation rather than an actual group. + * + * The filesystem isn't permitted to mix writes with groups and + * writes without groups as the NULL group is used to indicate + * that no group is set. + */ + if (unlikely(group != netfs_group) && + group != NETFS_FOLIO_COPY_TO_CACHE && + group) { + WARN_ON_ONCE(!netfs_group); + goto flush_content; + } + /* Decide how we should modify a folio. We might be attempting * to do write-streaming, as we don't want to a local RMW cycle * if we can avoid it. If we're doing local caching or content @@ -209,22 +211,14 @@ ssize_t netfs_perform_write(struct kiocb *iocb, struct iov_iter *iter, * file is open readably, then we let ->read_folio() fill in * the gaps. */ - finfo = netfs_folio_info(folio); - group = netfs_folio_group(folio); - - if (unlikely(group != netfs_group) && - group != NETFS_FOLIO_COPY_TO_CACHE) - goto flush_content; - if (folio_test_uptodate(folio)) { if (mapping_writably_mapped(mapping)) flush_dcache_folio(folio); copied = copy_folio_from_iter_atomic(folio, offset, part, iter); if (unlikely(copied == 0)) goto copy_failed; - netfs_set_group(folio, netfs_group); trace = netfs_folio_is_uptodate; - goto copied; + goto copied_uptodate; } /* If the page is above the zero-point then we assume that the @@ -237,24 +231,22 @@ ssize_t netfs_perform_write(struct kiocb *iocb, struct iov_iter *iter, if (unlikely(copied == 0)) goto copy_failed; folio_zero_segment(folio, offset + copied, flen); - __netfs_set_group(folio, netfs_group); - folio_mark_uptodate(folio); - trace = netfs_modify_and_clear; - goto copied; + if (finfo) + trace = netfs_modify_and_clear_rm_finfo; + else + trace = netfs_modify_and_clear; + goto mark_uptodate; } /* See if we can write a whole folio in one go. */ if (!maybe_trouble && offset == 0 && part >= flen) { copied = copy_folio_from_iter_atomic(folio, offset, part, iter); if (likely(copied == part)) { - if (finfo) { + if (finfo) trace = netfs_whole_folio_modify_filled; - goto folio_now_filled; - } - __netfs_set_group(folio, netfs_group); - folio_mark_uptodate(folio); - trace = netfs_whole_folio_modify; - goto copied; + else + trace = netfs_whole_folio_modify; + goto mark_uptodate; } if (copied == 0) goto copy_failed; @@ -272,7 +264,7 @@ ssize_t netfs_perform_write(struct kiocb *iocb, struct iov_iter *iter, finfo->dirty_len += finfo->dirty_offset; if (finfo->dirty_len == flen) { trace = netfs_whole_folio_modify_filled_efault; - goto folio_now_filled; + goto mark_uptodate; } if (copied > finfo->dirty_len) finfo->dirty_len = copied; @@ -300,11 +292,11 @@ ssize_t netfs_perform_write(struct kiocb *iocb, struct iov_iter *iter, copied = copy_folio_from_iter_atomic(folio, offset, part, iter); if (unlikely(copied == 0)) goto copy_failed; - netfs_set_group(folio, netfs_group); trace = netfs_just_prefetch; - goto copied; + goto copied_uptodate; } + /* Do a streaming write on a folio that has nothing in it yet. */ if (!finfo) { ret = -EIO; if (WARN_ON(folio_get_private(folio))) @@ -313,10 +305,8 @@ ssize_t netfs_perform_write(struct kiocb *iocb, struct iov_iter *iter, if (unlikely(copied == 0)) goto copy_failed; if (offset == 0 && copied == flen) { - __netfs_set_group(folio, netfs_group); - folio_mark_uptodate(folio); trace = netfs_streaming_filled_page; - goto copied; + goto mark_uptodate; } finfo = kzalloc_obj(*finfo); @@ -345,7 +335,7 @@ ssize_t netfs_perform_write(struct kiocb *iocb, struct iov_iter *iter, finfo->dirty_len += copied; if (finfo->dirty_offset == 0 && finfo->dirty_len == flen) { trace = netfs_streaming_cont_filled_page; - goto folio_now_filled; + goto mark_uptodate; } trace = netfs_streaming_write_cont; goto copied; @@ -361,13 +351,36 @@ ssize_t netfs_perform_write(struct kiocb *iocb, struct iov_iter *iter, goto out; continue; - folio_now_filled: - if (finfo->netfs_group) - folio_change_private(folio, finfo->netfs_group); - else - folio_detach_private(folio); + /* Mark a folio as being up to data when we've filled it + * completely. If the folio has a group attached, then it must + * be the same group, otherwise we should have flushed it out + * above. We have to get rid of the netfs_folio struct if + * there was one. + */ + mark_uptodate: folio_mark_uptodate(folio); - kfree(finfo); + + copied_uptodate: + priv = folio_get_private(folio); + if (likely(priv == netfs_group)) { + /* Already set correctly; no change required. */ + } else if (priv == NETFS_FOLIO_COPY_TO_CACHE) { + if (!netfs_group) + folio_detach_private(folio); + else + folio_change_private(folio, netfs_get_group(netfs_group)); + } else if (!priv) { + folio_attach_private(folio, netfs_get_group(netfs_group)); + } else { + WARN_ON_ONCE(!finfo); + if (netfs_group) + /* finfo->netfs_group has a ref */ + folio_change_private(folio, netfs_group); + else + folio_detach_private(folio); + kfree(finfo); + } + copied: trace_netfs_folio(folio, trace); flush_dcache_folio(folio); @@ -530,6 +543,7 @@ vm_fault_t netfs_page_mkwrite(struct vm_fault *vmf, struct netfs_group *netfs_gr struct inode *inode = file_inode(file); struct netfs_inode *ictx = netfs_inode(inode); vm_fault_t ret = VM_FAULT_NOPAGE; + void *priv; int err; _enter("%lx", folio->index); @@ -550,7 +564,9 @@ vm_fault_t netfs_page_mkwrite(struct vm_fault *vmf, struct netfs_group *netfs_gr } group = netfs_folio_group(folio); - if (group != netfs_group && group != NETFS_FOLIO_COPY_TO_CACHE) { + if (group && + group != netfs_group && + group != NETFS_FOLIO_COPY_TO_CACHE) { folio_unlock(folio); err = filemap_fdatawrite_range(mapping, folio_pos(folio), @@ -572,7 +588,19 @@ vm_fault_t netfs_page_mkwrite(struct vm_fault *vmf, struct netfs_group *netfs_gr trace_netfs_folio(folio, netfs_folio_trace_mkwrite_plus); else trace_netfs_folio(folio, netfs_folio_trace_mkwrite); - netfs_set_group(folio, netfs_group); + + priv = folio_get_private(folio); + if (priv != netfs_group) { + if (!netfs_group && priv == NETFS_FOLIO_COPY_TO_CACHE) + folio_detach_private(folio); + else if (netfs_group && priv == NETFS_FOLIO_COPY_TO_CACHE) + folio_change_private(folio, netfs_get_group(netfs_group)); + else if (netfs_group && !priv) + folio_attach_private(folio, netfs_get_group(netfs_group)); + else + WARN_ON_ONCE(1); + } + file_update_time(file); set_bit(NETFS_ICTX_MODIFIED_ATTR, &ictx->flags); if (ictx->ops->post_modify) diff --git a/include/trace/events/netfs.h b/include/trace/events/netfs.h index aa9940ba307b..082cb03c6131 100644 --- a/include/trace/events/netfs.h +++ b/include/trace/events/netfs.h @@ -181,6 +181,7 @@ EM(netfs_whole_folio_modify_filled, "mod-whole-f+") \ EM(netfs_whole_folio_modify_filled_efault, "mod-whole-f+!") \ EM(netfs_modify_and_clear, "mod-n-clear") \ + EM(netfs_modify_and_clear_rm_finfo, "mod-n-clear+") \ EM(netfs_streaming_write, "mod-streamw") \ EM(netfs_streaming_write_cont, "mod-streamw+") \ EM(netfs_flush_content, "flush") \ -- cgit v1.2.3 From ded0c6f1606061148c202825f7e53d711f9f84cf Mon Sep 17 00:00:00 2001 From: David Howells Date: Tue, 12 May 2026 13:33:59 +0100 Subject: netfs: Fix netfs_read_folio() to wait on writeback Fix netfs_read_folio() to wait for an ongoing writeback to complete so that it can trust the dirty flag and whatever is attached to folio->private (folio->private may get cleaned up by the collector before it clears the writeback flag). Fixes: ee4cdf7ba857 ("netfs: Speed up buffered reading") Closes: https://sashiko.dev/#/patchset/20260414082004.3756080-1-dhowells%40redhat.com Signed-off-by: David Howells Link: https://patch.msgid.link/20260512123404.719402-23-dhowells@redhat.com cc: Paulo Alcantara cc: Matthew Wilcox cc: netfs@lists.linux.dev cc: linux-fsdevel@vger.kernel.org Signed-off-by: Christian Brauner --- fs/netfs/buffered_read.c | 2 ++ 1 file changed, 2 insertions(+) diff --git a/fs/netfs/buffered_read.c b/fs/netfs/buffered_read.c index 83d0b8153e96..76d0f6a29aba 100644 --- a/fs/netfs/buffered_read.c +++ b/fs/netfs/buffered_read.c @@ -503,6 +503,8 @@ int netfs_read_folio(struct file *file, struct folio *folio) struct netfs_inode *ctx = netfs_inode(mapping->host); int ret; + folio_wait_writeback(folio); + if (folio_test_dirty(folio)) return netfs_read_gaps(file, folio); -- cgit v1.2.3 From 9871938f99cc6cb266a77265491660e2375271f5 Mon Sep 17 00:00:00 2001 From: David Howells Date: Tue, 12 May 2026 13:34:00 +0100 Subject: netfs, afs: Fix write skipping in dir/link writepages Fix netfs_write_single() and afs_single_writepages() to better handle a write that would be skipped due to lock contention and WB_SYNC_NONE by returning 1 from netfs_write_single() if it skipped and making afs_single_writepages() skip also. If a skip occurs, the inode must be re-marked as the VFS may have cleared the mark. This is really only theoretical for directories in netfs_write_single() as the only path to that is through afs_single_writepages() that takes the ->validate_lock around it, thereby serialising it. Fixes: 6dd80936618c ("afs: Use netfslib for directories") Signed-off-by: David Howells Link: https://patch.msgid.link/20260512123404.719402-24-dhowells@redhat.com cc: Marc Dionne cc: linux-afs@lists.infradead.org cc: linux-fsdevel@vger.kernel.org Signed-off-by: Christian Brauner --- fs/afs/dir.c | 11 ++++++++++- fs/netfs/write_issue.c | 7 ++++++- 2 files changed, 16 insertions(+), 2 deletions(-) diff --git a/fs/afs/dir.c b/fs/afs/dir.c index aaaa55878ffd..d1542a1a50bf 100644 --- a/fs/afs/dir.c +++ b/fs/afs/dir.c @@ -2206,7 +2206,14 @@ int afs_single_writepages(struct address_space *mapping, /* Need to lock to prevent the folio queue and folios from being thrown * away. */ - down_read(&dvnode->validate_lock); + if (!down_read_trylock(&dvnode->validate_lock)) { + if (wbc->sync_mode == WB_SYNC_NONE) { + /* The VFS will have undirtied the inode. */ + netfs_single_mark_inode_dirty(&dvnode->netfs.inode); + return 0; + } + down_read(&dvnode->validate_lock); + } if (is_dir ? test_bit(AFS_VNODE_DIR_VALID, &dvnode->flags) : @@ -2214,6 +2221,8 @@ int afs_single_writepages(struct address_space *mapping, iov_iter_folio_queue(&iter, ITER_SOURCE, dvnode->directory, 0, 0, i_size_read(&dvnode->netfs.inode)); ret = netfs_writeback_single(mapping, wbc, &iter); + if (ret == 1) + ret = 0; /* Skipped write due to lock conflict. */ } up_read(&dvnode->validate_lock); diff --git a/fs/netfs/write_issue.c b/fs/netfs/write_issue.c index 03961622996b..c03c7cc45e47 100644 --- a/fs/netfs/write_issue.c +++ b/fs/netfs/write_issue.c @@ -830,6 +830,9 @@ static int netfs_write_folio_single(struct netfs_io_request *wreq, * * Write a monolithic, non-pagecache object back to the server and/or * the cache. + * + * Return: 0 if successful; 1 if skipped due to lock conflict and WB_SYNC_NONE; + * or a negative error code. */ int netfs_writeback_single(struct address_space *mapping, struct writeback_control *wbc, @@ -846,8 +849,10 @@ int netfs_writeback_single(struct address_space *mapping, if (!mutex_trylock(&ictx->wb_lock)) { if (wbc->sync_mode == WB_SYNC_NONE) { + /* The VFS will have undirtied the inode. */ + netfs_single_mark_inode_dirty(&ictx->inode); netfs_stat(&netfs_n_wb_lock_skip); - return 0; + return 1; } netfs_stat(&netfs_n_wb_lock_wait); mutex_lock(&ictx->wb_lock); -- cgit v1.2.3 From c0410adf3da6db46f3513411fcf95e63c2f1d1ad Mon Sep 17 00:00:00 2001 From: David Howells Date: Tue, 12 May 2026 13:34:01 +0100 Subject: afs: Fix the locking used by afs_get_link() The afs filesystem in the kernel doesn't do locking correctly for symbolic links. There are a number of problems: (1) It doesn't do any locking around afs_read_single() to prevent races between multiple ->get_link() calls, thereby allowing the possibility of leaks. (2) It doesn't use RCU barriering when accessing the buffer pointers during RCU pathwalk. (3) It can race with another thread updating the contents of the symlink if a third party updated it on the server. Fix this by the following means: (0) Move symlink handling into its own file as this makes it more complicated. (1) Take the validate_lock around afs_read_single() to prevent races between multiple ->get_link() calls. (2) Keep a separate copy of the symlink contents with an rcu_head. This is always going to be a lot smaller than a page, so it can be kmalloc'd and save quite a bit of memory. It also needs a refcount for non-RCU pathwalk. (3) Split the symlink read and write-to-cache routines in afs from those for directories. (4) Discard the I/O buffer as soon as the write-to-cache completes as this is a full page (plus a folio_queue). (5) If there's no cache, discard the I/O buffer immediately after reading and copying if there is no cache. Fixes: eae9e78951bb ("afs: Use netfslib for symlinks, allowing them to be cached") Fixes: 6698c02d64b2 ("afs: Locally initialise the contents of a new symlink on creation") Closes: https://sashiko.dev/#/patchset/20260326104544.509518-1-dhowells%40redhat.com Signed-off-by: David Howells Link: https://patch.msgid.link/20260512123404.719402-25-dhowells@redhat.com cc: Marc Dionne cc: linux-afs@lists.infradead.org cc: linux-fsdevel@vger.kernel.org Signed-off-by: Christian Brauner --- fs/afs/Makefile | 1 + fs/afs/dir.c | 68 ++++++------- fs/afs/fsclient.c | 4 +- fs/afs/inode.c | 96 +----------------- fs/afs/internal.h | 34 +++++-- fs/afs/symlink.c | 278 ++++++++++++++++++++++++++++++++++++++++++++++++++++ fs/afs/validation.c | 14 ++- fs/afs/yfsclient.c | 4 +- 8 files changed, 357 insertions(+), 142 deletions(-) create mode 100644 fs/afs/symlink.c diff --git a/fs/afs/Makefile b/fs/afs/Makefile index b49b8fe682f3..0d8f1982d596 100644 --- a/fs/afs/Makefile +++ b/fs/afs/Makefile @@ -30,6 +30,7 @@ kafs-y := \ server.o \ server_list.o \ super.o \ + symlink.o \ validation.o \ vlclient.o \ vl_alias.o \ diff --git a/fs/afs/dir.c b/fs/afs/dir.c index d1542a1a50bf..498b99ccdf0e 100644 --- a/fs/afs/dir.c +++ b/fs/afs/dir.c @@ -44,6 +44,8 @@ static int afs_symlink(struct mnt_idmap *idmap, struct inode *dir, static int afs_rename(struct mnt_idmap *idmap, struct inode *old_dir, struct dentry *old_dentry, struct inode *new_dir, struct dentry *new_dentry, unsigned int flags); +static int afs_dir_writepages(struct address_space *mapping, + struct writeback_control *wbc); const struct file_operations afs_dir_file_operations = { .open = afs_dir_open, @@ -68,7 +70,7 @@ const struct inode_operations afs_dir_inode_operations = { }; const struct address_space_operations afs_dir_aops = { - .writepages = afs_single_writepages, + .writepages = afs_dir_writepages, }; const struct dentry_operations afs_fs_dentry_operations = { @@ -233,22 +235,13 @@ static ssize_t afs_do_read_single(struct afs_vnode *dvnode, struct file *file) struct iov_iter iter; ssize_t ret; loff_t i_size; - bool is_dir = (S_ISDIR(dvnode->netfs.inode.i_mode) && - !test_bit(AFS_VNODE_MOUNTPOINT, &dvnode->flags)); i_size = i_size_read(&dvnode->netfs.inode); - if (is_dir) { - if (i_size < AFS_DIR_BLOCK_SIZE) - return afs_bad(dvnode, afs_file_error_dir_small); - if (i_size > AFS_DIR_BLOCK_SIZE * 1024) { - trace_afs_file_error(dvnode, -EFBIG, afs_file_error_dir_big); - return -EFBIG; - } - } else { - if (i_size > AFSPATHMAX) { - trace_afs_file_error(dvnode, -EFBIG, afs_file_error_dir_big); - return -EFBIG; - } + if (i_size < AFS_DIR_BLOCK_SIZE) + return afs_bad(dvnode, afs_file_error_dir_small); + if (i_size > AFS_DIR_BLOCK_SIZE * 1024) { + trace_afs_file_error(dvnode, -EFBIG, afs_file_error_dir_big); + return -EFBIG; } /* Expand the storage. TODO: Shrink the storage too. */ @@ -277,24 +270,18 @@ static ssize_t afs_do_read_single(struct afs_vnode *dvnode, struct file *file) * buffer. */ ret = -ESTALE; - } else if (is_dir) { + } else { int ret2 = afs_dir_check(dvnode); if (ret2 < 0) ret = ret2; - } else if (i_size < folioq_folio_size(dvnode->directory, 0)) { - /* NUL-terminate a symlink. */ - char *symlink = kmap_local_folio(folioq_folio(dvnode->directory, 0), 0); - - symlink[i_size] = 0; - kunmap_local(symlink); } } return ret; } -ssize_t afs_read_single(struct afs_vnode *dvnode, struct file *file) +static ssize_t afs_read_single(struct afs_vnode *dvnode, struct file *file) { ssize_t ret; @@ -1763,13 +1750,20 @@ error: return ret; } +static void afs_symlink_put(struct afs_operation *op) +{ + kfree(op->create.symlink); + op->create.symlink = NULL; + afs_create_put(op); +} + static const struct afs_operation_ops afs_symlink_operation = { .issue_afs_rpc = afs_fs_symlink, .issue_yfs_rpc = yfs_fs_symlink, .success = afs_create_success, .aborted = afs_check_for_remote_deletion, .edit_dir = afs_create_edit_dir, - .put = afs_create_put, + .put = afs_symlink_put, }; /* @@ -1779,7 +1773,9 @@ static int afs_symlink(struct mnt_idmap *idmap, struct inode *dir, struct dentry *dentry, const char *content) { struct afs_operation *op; + struct afs_symlink *symlink; struct afs_vnode *dvnode = AFS_FS_I(dir); + size_t clen = strlen(content); int ret; _enter("{%llx:%llu},{%pd},%s", @@ -1791,12 +1787,20 @@ static int afs_symlink(struct mnt_idmap *idmap, struct inode *dir, goto error; ret = -EINVAL; - if (strlen(content) >= AFSPATHMAX) + if (clen >= AFSPATHMAX) + goto error; + + ret = -ENOMEM; + symlink = kmalloc_flex(struct afs_symlink, content, clen + 1, GFP_KERNEL); + if (!symlink) goto error; + refcount_set(&symlink->ref, 1); + memcpy(symlink->content, content, clen + 1); op = afs_alloc_operation(NULL, dvnode->volume); if (IS_ERR(op)) { ret = PTR_ERR(op); + kfree(symlink); goto error; } @@ -1808,7 +1812,7 @@ static int afs_symlink(struct mnt_idmap *idmap, struct inode *dir, op->dentry = dentry; op->ops = &afs_symlink_operation; op->create.reason = afs_edit_dir_for_symlink; - op->create.symlink = content; + op->create.symlink = symlink; op->mtime = current_time(dir); ret = afs_do_sync_operation(op); afs_dir_unuse_cookie(dvnode, ret); @@ -2192,15 +2196,13 @@ error: } /* - * Write the file contents to the cache as a single blob. + * Write the directory contents to the cache as a single blob. */ -int afs_single_writepages(struct address_space *mapping, - struct writeback_control *wbc) +static int afs_dir_writepages(struct address_space *mapping, + struct writeback_control *wbc) { struct afs_vnode *dvnode = AFS_FS_I(mapping->host); struct iov_iter iter; - bool is_dir = (S_ISDIR(dvnode->netfs.inode.i_mode) && - !test_bit(AFS_VNODE_MOUNTPOINT, &dvnode->flags)); int ret = 0; /* Need to lock to prevent the folio queue and folios from being thrown @@ -2215,9 +2217,7 @@ int afs_single_writepages(struct address_space *mapping, down_read(&dvnode->validate_lock); } - if (is_dir ? - test_bit(AFS_VNODE_DIR_VALID, &dvnode->flags) : - atomic64_read(&dvnode->cb_expires_at) != AFS_NO_CB_PROMISE) { + if (test_bit(AFS_VNODE_DIR_VALID, &dvnode->flags)) { iov_iter_folio_queue(&iter, ITER_SOURCE, dvnode->directory, 0, 0, i_size_read(&dvnode->netfs.inode)); ret = netfs_writeback_single(mapping, wbc, &iter); diff --git a/fs/afs/fsclient.c b/fs/afs/fsclient.c index 95494d5f2b8a..a2ffd60889f8 100644 --- a/fs/afs/fsclient.c +++ b/fs/afs/fsclient.c @@ -886,7 +886,7 @@ void afs_fs_symlink(struct afs_operation *op) namesz = name->len; padsz = (4 - (namesz & 3)) & 3; - c_namesz = strlen(op->create.symlink); + c_namesz = strlen(op->create.symlink->content); c_padsz = (4 - (c_namesz & 3)) & 3; reqsz = (6 * 4) + namesz + padsz + c_namesz + c_padsz + (6 * 4); @@ -910,7 +910,7 @@ void afs_fs_symlink(struct afs_operation *op) bp = (void *) bp + padsz; } *bp++ = htonl(c_namesz); - memcpy(bp, op->create.symlink, c_namesz); + memcpy(bp, op->create.symlink->content, c_namesz); bp = (void *) bp + c_namesz; if (c_padsz > 0) { memset(bp, 0, c_padsz); diff --git a/fs/afs/inode.c b/fs/afs/inode.c index 19fe2e392885..3f48458694ba 100644 --- a/fs/afs/inode.c +++ b/fs/afs/inode.c @@ -25,96 +25,6 @@ #include "internal.h" #include "afs_fs.h" -void afs_init_new_symlink(struct afs_vnode *vnode, struct afs_operation *op) -{ - size_t size = strlen(op->create.symlink) + 1; - size_t dsize = 0; - char *p; - - if (netfs_alloc_folioq_buffer(NULL, &vnode->directory, &dsize, size, - mapping_gfp_mask(vnode->netfs.inode.i_mapping)) < 0) - return; - - vnode->directory_size = dsize; - p = kmap_local_folio(folioq_folio(vnode->directory, 0), 0); - memcpy(p, op->create.symlink, size); - kunmap_local(p); - set_bit(AFS_VNODE_DIR_READ, &vnode->flags); - netfs_single_mark_inode_dirty(&vnode->netfs.inode); -} - -static void afs_put_link(void *arg) -{ - struct folio *folio = virt_to_folio(arg); - - kunmap_local(arg); - folio_put(folio); -} - -const char *afs_get_link(struct dentry *dentry, struct inode *inode, - struct delayed_call *callback) -{ - struct afs_vnode *vnode = AFS_FS_I(inode); - struct folio *folio; - char *content; - ssize_t ret; - - if (!dentry) { - /* RCU pathwalk. */ - if (!test_bit(AFS_VNODE_DIR_READ, &vnode->flags) || !afs_check_validity(vnode)) - return ERR_PTR(-ECHILD); - goto good; - } - - if (test_bit(AFS_VNODE_DIR_READ, &vnode->flags)) - goto fetch; - - ret = afs_validate(vnode, NULL); - if (ret < 0) - return ERR_PTR(ret); - - if (!test_and_clear_bit(AFS_VNODE_ZAP_DATA, &vnode->flags) && - test_bit(AFS_VNODE_DIR_READ, &vnode->flags)) - goto good; - -fetch: - ret = afs_read_single(vnode, NULL); - if (ret < 0) - return ERR_PTR(ret); - set_bit(AFS_VNODE_DIR_READ, &vnode->flags); - -good: - folio = folioq_folio(vnode->directory, 0); - folio_get(folio); - content = kmap_local_folio(folio, 0); - set_delayed_call(callback, afs_put_link, content); - return content; -} - -int afs_readlink(struct dentry *dentry, char __user *buffer, int buflen) -{ - DEFINE_DELAYED_CALL(done); - const char *content; - int len; - - content = afs_get_link(dentry, d_inode(dentry), &done); - if (IS_ERR(content)) { - do_delayed_call(&done); - return PTR_ERR(content); - } - - len = umin(strlen(content), buflen); - if (copy_to_user(buffer, content, len)) - len = -EFAULT; - do_delayed_call(&done); - return len; -} - -static const struct inode_operations afs_symlink_inode_operations = { - .get_link = afs_get_link, - .readlink = afs_readlink, -}; - static noinline void dump_vnode(struct afs_vnode *vnode, struct afs_vnode *parent_vnode) { static unsigned long once_only; @@ -214,7 +124,7 @@ static int afs_inode_init_from_status(struct afs_operation *op, inode->i_mode = S_IFLNK | status->mode; inode->i_op = &afs_symlink_inode_operations; } - inode->i_mapping->a_ops = &afs_dir_aops; + inode->i_mapping->a_ops = &afs_symlink_aops; inode_nohighmem(inode); mapping_set_release_always(inode->i_mapping); break; @@ -769,12 +679,14 @@ void afs_evict_inode(struct inode *inode) .range_end = LLONG_MAX, }; - afs_single_writepages(inode->i_mapping, &wbc); + inode->i_mapping->a_ops->writepages(inode->i_mapping, &wbc); } netfs_wait_for_outstanding_io(inode); truncate_inode_pages_final(&inode->i_data); netfs_free_folioq_buffer(vnode->directory); + if (vnode->symlink) + afs_evict_symlink(vnode); afs_set_cache_aux(vnode, &aux); netfs_clear_inode_writeback(inode, &aux); diff --git a/fs/afs/internal.h b/fs/afs/internal.h index 816dc848ea71..0b72a8566299 100644 --- a/fs/afs/internal.h +++ b/fs/afs/internal.h @@ -710,6 +710,7 @@ struct afs_vnode { #define AFS_VNODE_DIR_READ 11 /* Set if we've read a dir's contents */ struct folio_queue *directory; /* Directory contents */ + struct afs_symlink __rcu *symlink; /* Symlink content */ struct list_head wb_keys; /* List of keys available for writeback */ struct list_head pending_locks; /* locks waiting to be granted */ struct list_head granted_locks; /* locks granted on this file */ @@ -776,6 +777,15 @@ struct afs_permits { struct afs_permit permits[] __counted_by(nr_permits); /* List of permits sorted by key pointer */ }; +/* + * Copy of symlink content for normal use. + */ +struct afs_symlink { + struct rcu_head rcu; + refcount_t ref; + char content[]; +}; + /* * Error prioritisation and accumulation. */ @@ -887,7 +897,7 @@ struct afs_operation { struct { int reason; /* enum afs_edit_dir_reason */ mode_t mode; - const char *symlink; + struct afs_symlink *symlink; } create; struct { bool need_rehash; @@ -1098,13 +1108,10 @@ extern const struct inode_operations afs_dir_inode_operations; extern const struct address_space_operations afs_dir_aops; extern const struct dentry_operations afs_fs_dentry_operations; -ssize_t afs_read_single(struct afs_vnode *dvnode, struct file *file); ssize_t afs_read_dir(struct afs_vnode *dvnode, struct file *file) __acquires(&dvnode->validate_lock); extern void afs_d_release(struct dentry *); extern void afs_check_for_remote_deletion(struct afs_operation *); -int afs_single_writepages(struct address_space *mapping, - struct writeback_control *wbc); /* * dir_edit.c @@ -1247,10 +1254,6 @@ extern void afs_fs_probe_cleanup(struct afs_net *); */ extern const struct afs_operation_ops afs_fetch_status_operation; -void afs_init_new_symlink(struct afs_vnode *vnode, struct afs_operation *op); -const char *afs_get_link(struct dentry *dentry, struct inode *inode, - struct delayed_call *callback); -int afs_readlink(struct dentry *dentry, char __user *buffer, int buflen); extern void afs_vnode_commit_status(struct afs_operation *, struct afs_vnode_param *); extern int afs_fetch_status(struct afs_vnode *, struct key *, bool, afs_access_t *); extern int afs_ilookup5_test_by_fid(struct inode *, void *); @@ -1600,6 +1603,21 @@ void afs_detach_volume_from_servers(struct afs_volume *volume, struct afs_server extern int __init afs_fs_init(void); extern void afs_fs_exit(void); +/* + * symlink.c + */ +extern const struct inode_operations afs_symlink_inode_operations; +extern const struct address_space_operations afs_symlink_aops; + +void afs_invalidate_symlink(struct afs_vnode *vnode); +void afs_evict_symlink(struct afs_vnode *vnode); +void afs_init_new_symlink(struct afs_vnode *vnode, struct afs_operation *op); +const char *afs_get_link(struct dentry *dentry, struct inode *inode, + struct delayed_call *callback); +int afs_readlink(struct dentry *dentry, char __user *buffer, int buflen); +int afs_symlink_writepages(struct address_space *mapping, + struct writeback_control *wbc); + /* * validation.c */ diff --git a/fs/afs/symlink.c b/fs/afs/symlink.c new file mode 100644 index 000000000000..ed5868369f37 --- /dev/null +++ b/fs/afs/symlink.c @@ -0,0 +1,278 @@ +// SPDX-License-Identifier: GPL-2.0-or-later +/* AFS filesystem symbolic link handling + * + * Copyright (C) 2026 Red Hat, Inc. All Rights Reserved. + * Written by David Howells (dhowells@redhat.com) + */ + +#include +#include +#include +#include +#include +#include "internal.h" + +static void afs_put_symlink(struct afs_symlink *symlink) +{ + if (refcount_dec_and_test(&symlink->ref)) + kfree_rcu(symlink, rcu); +} + +static void afs_replace_symlink(struct afs_vnode *vnode, struct afs_symlink *symlink) +{ + struct afs_symlink *old; + + old = rcu_replace_pointer(vnode->symlink, symlink, + lockdep_is_held(&vnode->validate_lock)); + if (old) + afs_put_symlink(old); +} + +/* + * In the event that a third-party update of a symlink occurs, dispose of the + * copy of the old contents. Called under ->validate_lock. + */ +void afs_invalidate_symlink(struct afs_vnode *vnode) +{ + afs_replace_symlink(vnode, NULL); +} + +/* + * Dispose of a symlink copy during inode deletion. + */ +void afs_evict_symlink(struct afs_vnode *vnode) +{ + struct afs_symlink *old; + + old = rcu_replace_pointer(vnode->symlink, NULL, true); + if (old) + afs_put_symlink(old); + +} + +/* + * Set up a locally created symlink inode for immediate write to the cache. + */ +void afs_init_new_symlink(struct afs_vnode *vnode, struct afs_operation *op) +{ + struct afs_symlink *symlink = op->create.symlink; + size_t dsize = 0; + size_t size = strlen(symlink->content) + 1; + char *p; + + rcu_assign_pointer(vnode->symlink, symlink); + op->create.symlink = NULL; + + if (!fscache_cookie_enabled(netfs_i_cookie(&vnode->netfs))) + return; + + if (netfs_alloc_folioq_buffer(NULL, &vnode->directory, &dsize, size, + mapping_gfp_mask(vnode->netfs.inode.i_mapping)) < 0) + return; + + vnode->directory_size = dsize; + p = kmap_local_folio(folioq_folio(vnode->directory, 0), 0); + memcpy(p, symlink->content, size); + kunmap_local(p); + netfs_single_mark_inode_dirty(&vnode->netfs.inode); +} + +/* + * Read a symlink in a single download. + */ +static ssize_t afs_do_read_symlink(struct afs_vnode *vnode) +{ + struct afs_symlink *symlink; + struct iov_iter iter; + ssize_t ret; + loff_t i_size; + + i_size = i_size_read(&vnode->netfs.inode); + if (i_size > PAGE_SIZE - 1) { + trace_afs_file_error(vnode, -EFBIG, afs_file_error_dir_big); + return -EFBIG; + } + + if (!vnode->directory) { + size_t cur_size = 0; + + ret = netfs_alloc_folioq_buffer(NULL, + &vnode->directory, &cur_size, PAGE_SIZE, + mapping_gfp_mask(vnode->netfs.inode.i_mapping)); + vnode->directory_size = PAGE_SIZE - 1; + if (ret < 0) + return ret; + } + + iov_iter_folio_queue(&iter, ITER_DEST, vnode->directory, 0, 0, PAGE_SIZE); + + /* AFS requires us to perform the read of a symlink as a single unit to + * avoid issues with the content being changed between reads. + */ + ret = netfs_read_single(&vnode->netfs.inode, NULL, &iter); + if (ret >= 0) { + i_size = ret; + if (i_size > PAGE_SIZE - 1) { + trace_afs_file_error(vnode, -EFBIG, afs_file_error_dir_big); + return -EFBIG; + } + vnode->directory_size = i_size; + + /* Copy the symlink. */ + symlink = kmalloc_flex(struct afs_symlink, content, i_size + 1, + GFP_KERNEL); + if (!symlink) + return -ENOMEM; + + refcount_set(&symlink->ref, 1); + symlink->content[i_size] = 0; + + const char *s = kmap_local_folio(folioq_folio(vnode->directory, 0), 0); + + memcpy(symlink->content, s, i_size); + kunmap_local(s); + + afs_replace_symlink(vnode, symlink); + } + + if (!fscache_cookie_enabled(netfs_i_cookie(&vnode->netfs))) { + netfs_free_folioq_buffer(vnode->directory); + vnode->directory = NULL; + vnode->directory_size = 0; + } + + return ret; +} + +static ssize_t afs_read_symlink(struct afs_vnode *vnode) +{ + ssize_t ret; + + fscache_use_cookie(afs_vnode_cache(vnode), false); + ret = afs_do_read_symlink(vnode); + fscache_unuse_cookie(afs_vnode_cache(vnode), NULL, NULL); + return ret; +} + +static void afs_put_link(void *arg) +{ + afs_put_symlink(arg); +} + +const char *afs_get_link(struct dentry *dentry, struct inode *inode, + struct delayed_call *callback) +{ + struct afs_symlink *symlink; + struct afs_vnode *vnode = AFS_FS_I(inode); + ssize_t ret; + + if (!dentry) { + /* RCU pathwalk. */ + symlink = rcu_dereference(vnode->symlink); + if (!symlink || !afs_check_validity(vnode)) + return ERR_PTR(-ECHILD); + set_delayed_call(callback, NULL, NULL); + return symlink->content; + } + + if (vnode->symlink) { + ret = afs_validate(vnode, NULL); + if (ret < 0) + return ERR_PTR(ret); + + down_read(&vnode->validate_lock); + if (vnode->symlink) + goto good; + up_read(&vnode->validate_lock); + } + + if (down_write_killable(&vnode->validate_lock) < 0) + return ERR_PTR(-ERESTARTSYS); + if (!vnode->symlink) { + ret = afs_read_symlink(vnode); + if (ret < 0) { + up_write(&vnode->validate_lock); + return ERR_PTR(ret); + } + } + + downgrade_write(&vnode->validate_lock); + +good: + symlink = rcu_dereference_protected(vnode->symlink, + lockdep_is_held(&vnode->validate_lock)); + refcount_inc(&symlink->ref); + up_read(&vnode->validate_lock); + + set_delayed_call(callback, afs_put_link, symlink); + return symlink->content; +} + +int afs_readlink(struct dentry *dentry, char __user *buffer, int buflen) +{ + DEFINE_DELAYED_CALL(done); + const char *content; + int len; + + content = afs_get_link(dentry, d_inode(dentry), &done); + if (IS_ERR(content)) { + do_delayed_call(&done); + return PTR_ERR(content); + } + + len = umin(strlen(content), buflen); + if (copy_to_user(buffer, content, len)) + len = -EFAULT; + do_delayed_call(&done); + return len; +} + +/* + * Write the symlink contents to the cache as a single blob. We then throw + * away the page we used to receive it. + */ +int afs_symlink_writepages(struct address_space *mapping, + struct writeback_control *wbc) +{ + struct afs_vnode *vnode = AFS_FS_I(mapping->host); + struct iov_iter iter; + int ret = 0; + + if (!down_read_trylock(&vnode->validate_lock)) { + if (wbc->sync_mode == WB_SYNC_NONE) { + /* The VFS will have undirtied the inode. */ + netfs_single_mark_inode_dirty(&vnode->netfs.inode); + return 0; + } + down_read(&vnode->validate_lock); + } + + if (vnode->directory && + atomic64_read(&vnode->cb_expires_at) != AFS_NO_CB_PROMISE) { + iov_iter_folio_queue(&iter, ITER_SOURCE, vnode->directory, 0, 0, + i_size_read(&vnode->netfs.inode)); + ret = netfs_writeback_single(mapping, wbc, &iter); + } + + if (ret == 0) { + mutex_lock(&vnode->netfs.wb_lock); + netfs_free_folioq_buffer(vnode->directory); + vnode->directory = NULL; + vnode->directory_size = 0; + mutex_unlock(&vnode->netfs.wb_lock); + } else if (ret == 1) { + ret = 0; /* Skipped write due to lock conflict. */ + } + + up_read(&vnode->validate_lock); + return ret; +} + +const struct inode_operations afs_symlink_inode_operations = { + .get_link = afs_get_link, + .readlink = afs_readlink, +}; + +const struct address_space_operations afs_symlink_aops = { + .writepages = afs_symlink_writepages, +}; diff --git a/fs/afs/validation.c b/fs/afs/validation.c index 0ba8336c9025..e997563af658 100644 --- a/fs/afs/validation.c +++ b/fs/afs/validation.c @@ -465,11 +465,17 @@ int afs_validate(struct afs_vnode *vnode, struct key *key) vnode->cb_ro_snapshot = cb_ro_snapshot; vnode->cb_scrub = cb_scrub; - /* if the vnode's data version number changed then its contents are - * different */ + /* If the vnode's data version number changed then its contents are + * different. Note that afs_apply_status() doesn't set ZAP_DATA on + * directories. + */ zap |= test_and_clear_bit(AFS_VNODE_ZAP_DATA, &vnode->flags); - if (zap) - afs_zap_data(vnode); + if (zap) { + if (S_ISREG(vnode->netfs.inode.i_mode)) + afs_zap_data(vnode); + else if (S_ISLNK(vnode->netfs.inode.i_mode)) + afs_invalidate_symlink(vnode); + } up_write(&vnode->validate_lock); _leave(" = 0"); return 0; diff --git a/fs/afs/yfsclient.c b/fs/afs/yfsclient.c index 24fb562ebd33..d941179730a9 100644 --- a/fs/afs/yfsclient.c +++ b/fs/afs/yfsclient.c @@ -960,7 +960,7 @@ void yfs_fs_symlink(struct afs_operation *op) _enter(""); - contents_sz = strlen(op->create.symlink); + contents_sz = strlen(op->create.symlink->content); call = afs_alloc_flat_call(op->net, &yfs_RXYFSSymlink, sizeof(__be32) + sizeof(struct yfs_xdr_RPCFlags) + @@ -981,7 +981,7 @@ void yfs_fs_symlink(struct afs_operation *op) bp = xdr_encode_u32(bp, 0); /* RPC flags */ bp = xdr_encode_YFSFid(bp, &dvp->fid); bp = xdr_encode_name(bp, name); - bp = xdr_encode_string(bp, op->create.symlink, contents_sz); + bp = xdr_encode_string(bp, op->create.symlink->content, contents_sz); bp = xdr_encode_YFSStoreStatus(bp, &mode, &op->mtime); yfs_check_req(call, bp); -- cgit v1.2.3 From 8a220d1c312c66194f4a33dd52d1fba42bc2b341 Mon Sep 17 00:00:00 2001 From: Hongling Zeng Date: Wed, 13 May 2026 18:34:06 +0800 Subject: cachefiles: Fix error return when vfs_mkdir() fails When vfs_mkdir() fails, the error code is not extracted from the returned error pointer. This causes mkdir_error to be reached with ret=0, which leads to returning ERR_PTR(0) (NULL) instead of a proper error pointer. Fix this by extracting the error code from the error pointer when vfs_mkdir() fails. Fixes: 406fad7698f5 ("cachefiles: Fix oops in vfs_mkdir from cachefiles_get_directory") Signed-off-by: Hongling Zeng Link: https://patch.msgid.link/20260513103406.202320-1-zenghongling@kylinos.cn Signed-off-by: Christian Brauner --- fs/cachefiles/namei.c | 2 ++ 1 file changed, 2 insertions(+) diff --git a/fs/cachefiles/namei.c b/fs/cachefiles/namei.c index 1b83ed0e0a63..2937db690b40 100644 --- a/fs/cachefiles/namei.c +++ b/fs/cachefiles/namei.c @@ -130,6 +130,8 @@ retry: ret = cachefiles_inject_write_error(); if (ret == 0) { subdir = vfs_mkdir(&nop_mnt_idmap, d_inode(dir), subdir, 0700, NULL); + if (IS_ERR(subdir)) + ret = PTR_ERR(subdir); } else { end_creating(subdir); subdir = ERR_PTR(ret); -- cgit v1.2.3