linux-stable.git/fs/ceph, branch v6.11

netfs, ceph: Partially revert "netfs: Replace PG_fscache by setting folio->private and marking dirty"

2024-08-21T20:32:58+00:00

This partially reverts commit 2ff1e97587f4d398686f52c07afde3faf3da4e5c.

In addition to reverting the removal of PG_private_2 wrangling from the
buffered read code[1][2], the removal of the waits for PG_private_2 from
netfs_release_folio() and netfs_invalidate_folio() need reverting too.

It also adds a wait into ceph_evict_inode() to wait for netfs read and
copy-to-cache ops to complete.

Fixes: 2ff1e97587f4 ("netfs: Replace PG_fscache by setting folio->private and marking dirty")
Signed-off-by: David Howells 
Link: https://lore.kernel.org/r/3575457.1722355300@warthog.procyon.org.uk [1]
Link: https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/?id=8e5ced7804cb9184c4a23f8054551240562a8eda [2]
Link: https://lore.kernel.org/r/20240814203850.2240469-2-dhowells@redhat.com
cc: Max Kellermann 
cc: Ilya Dryomov 
cc: Xiubo Li 
cc: Jeff Layton 
cc: Matthew Wilcox 
cc: ceph-devel@vger.kernel.org
cc: netfs@lists.linux.dev
cc: linux-fsdevel@vger.kernel.org
cc: linux-mm@kvack.org
Signed-off-by: Christian Brauner

Merge tag 'vfs-6.11-rc4.fixes' of git://git.kernel.org/pub/scm/linux/kernel/git/vfs/vfs

2024-08-14T16:06:28+00:00

Pull vfs fixes from Christian Brauner:
"VFS:

- Fix the name of file lease slab cache. When file leases were split
out of file locks the name of the file lock slab cache was used for
the file leases slab cache as well.

- Fix a type in take_fd() helper.

- Fix infinite directory iteration for stable offsets in tmpfs.

- When the icache is pruned all reclaimable inodes are marked with
I_FREEING and other processes that try to lookup such inodes will
block.

But some filesystems like ext4 can trigger lookups in their inode
evict callback causing deadlocks. Ext4 does such lookups if the
ea_inode feature is used whereby a separate inode may be used to
store xattrs.

Introduce I_LRU_ISOLATING which pins the inode while its pages are
reclaimed. This avoids inode deletion during inode_lru_isolate()
avoiding the deadlock and evict is made to wait until
I_LRU_ISOLATING is done.

netfs:

- Fault in smaller chunks for non-large folio mappings for
filesystems that haven't been converted to large folios yet.

- Fix the CONFIG_NETFS_DEBUG config option. The config option was
renamed a short while ago and that introduced two minor issues.
First, it depended on CONFIG_NETFS whereas it wants to depend on
CONFIG_NETFS_SUPPORT. The former doesn't exist, while the latter
does. Second, the documentation for the config option wasn't fixed
up.

- Revert the removal of the PG_private_2 writeback flag as ceph is
using it and fix how that flag is handled in netfs.

- Fix DIO reads on 9p. A program watching a file on a 9p mount
wouldn't see any changes in the size of the file being exported by
the server if the file was changed directly in the source
filesystem. Fix this by attempting to read the full size specified
when a DIO read is requested.

- Fix a NULL pointer dereference bug due to a data race where a
cachefiles cookies was retired even though it was still in use.
Check the cookie's n_accesses counter before discarding it.

nsfs:

- Fix ioctl declaration for NS_GET_MNTNS_ID from _IO() to _IOR() as
the kernel is writing to userspace.

pidfs:

- Prevent the creation of pidfds for kthreads until we have a
use-case for it and we know the semantics we want. It also confuses
userspace why they can get pidfds for kthreads.

squashfs:

- Fix an unitialized value bug reported by KMSAN caused by a
corrupted symbolic link size read from disk. Check that the
symbolic link size is not larger than expected"

* tag 'vfs-6.11-rc4.fixes' of git://git.kernel.org/pub/scm/linux/kernel/git/vfs/vfs:
Squashfs: sanity check symbolic link size
9p: Fix DIO read through netfs
vfs: Don't evict inode under the inode lru traversing context
netfs: Fix handling of USE_PGPRIV2 and WRITE_TO_CACHE flags
netfs, ceph: Revert "netfs: Remove deprecated use of PG_private_2 as a second writeback flag"
file: fix typo in take_fd() comment
pidfd: prevent creation of pidfds for kthreads
netfs: clean up after renaming FSCACHE_DEBUG config
libfs: fix infinite directory reads for offset dir
nsfs: fix ioctl declaration
fs/netfs/fscache_cookie: add missing "n_accesses" check
filelock: fix name of file_lease slab cache
netfs: Fault in smaller chunks for non-large folio mappings

9p: Fix DIO read through netfs

2024-08-13T11:53:09+00:00

If a program is watching a file on a 9p mount, it won't see any change in
size if the file being exported by the server is changed directly in the
source filesystem, presumably because 9p doesn't have change notifications,
and because netfs skips the reads if the file is empty.

Fix this by attempting to read the full size specified when a DIO read is
requested (such as when 9p is operating in unbuffered mode) and dealing
with a short read if the EOF was less than the expected read.

To make this work, filesystems using netfslib must not set
NETFS_SREQ_CLEAR_TAIL if performing a DIO read where that read hit the EOF.
I don't want to mandatorily clear this flag in netfslib for DIO because,
say, ceph might make a read from an object that is not completely filled,
but does not reside at the end of file - and so we need to clear the
excess.

This can be tested by watching an empty file over 9p within a VM (such as
in the ktest framework):

        while true; do read content; if [ -n "$content" ]; then echo $content; break; fi; done < /host/tmp/foo

then writing something into the empty file.  The watcher should immediately
display the file content and break out of the loop.  Without this fix, it
remains in the loop indefinitely.

Fixes: 80105ed2fd27 ("9p: Use netfslib read/write_iter")
Closes: https://bugzilla.kernel.org/show_bug.cgi?id=218916
Signed-off-by: David Howells 
Link: https://lore.kernel.org/r/1229195.1723211769@warthog.procyon.org.uk
cc: Eric Van Hensbergen 
cc: Latchesar Ionkov 
cc: Christian Schoenebeck 
cc: Marc Dionne 
cc: Ilya Dryomov 
cc: Steve French 
cc: Paulo Alcantara 
cc: Trond Myklebust 
cc: v9fs@lists.linux.dev
cc: linux-afs@lists.infradead.org
cc: ceph-devel@vger.kernel.org
cc: linux-cifs@vger.kernel.org
cc: linux-nfs@vger.kernel.org
cc: netfs@lists.linux.dev
cc: linux-fsdevel@vger.kernel.org
Signed-off-by: Dominique Martinet 
Signed-off-by: Christian Brauner

netfs: Fix handling of USE_PGPRIV2 and WRITE_TO_CACHE flags

2024-08-12T20:03:27+00:00

The NETFS_RREQ_USE_PGPRIV2 and NETFS_RREQ_WRITE_TO_CACHE flags aren't used
correctly.  The problem is that we try to set them up in the request
initialisation, but we the cache may be in the process of setting up still,
and so the state may not be correct.  Further, we secondarily sample the
cache state and make contradictory decisions later.

The issue arises because we set up the cache resources, which allows the
cache's ->prepare_read() to switch on NETFS_SREQ_COPY_TO_CACHE - which
triggers cache writing even if we didn't set the flags when allocating.

Fix this in the following way:

 (1) Drop NETFS_ICTX_USE_PGPRIV2 and instead set NETFS_RREQ_USE_PGPRIV2 in
     ->init_request() rather than trying to juggle that in
     netfs_alloc_request().

 (2) Repurpose NETFS_RREQ_USE_PGPRIV2 to merely indicate that if caching is
     to be done, then PG_private_2 is to be used rather than only setting
     it if we decide to cache and then having netfs_rreq_unlock_folios()
     set the non-PG_private_2 writeback-to-cache if it wasn't set.

 (3) Split netfs_rreq_unlock_folios() into two functions, one of which
     contains the deprecated code for using PG_private_2 to avoid
     accidentally doing the writeback path - and always use it if
     USE_PGPRIV2 is set.

 (4) As NETFS_ICTX_USE_PGPRIV2 is removed, make netfs_write_begin() always
     wait for PG_private_2.  This function is deprecated and only used by
     ceph anyway, and so label it so.

 (5) Drop the NETFS_RREQ_WRITE_TO_CACHE flag and use
     fscache_operation_valid() on the cache_resources instead.  This has
     the advantage of picking up the result of netfs_begin_cache_read() and
     fscache_begin_write_operation() - which are called after the object is
     initialised and will wait for the cache to come to a usable state.

Just reverting ae678317b95e[1] isn't a sufficient fix, so this need to be
applied on top of that.  Without this as well, things like:

 rcu: INFO: rcu_sched detected expedited stalls on CPUs/tasks: {

and:

 WARNING: CPU: 13 PID: 3621 at fs/ceph/caps.c:3386

may happen, along with some UAFs due to PG_private_2 not getting used to
wait on writeback completion.

Fixes: 2ff1e97587f4 ("netfs: Replace PG_fscache by setting folio->private and marking dirty")
Reported-by: Max Kellermann 
Signed-off-by: David Howells 
cc: Ilya Dryomov 
cc: Xiubo Li 
cc: Hristo Venev 
cc: Jeff Layton 
cc: Matthew Wilcox 
cc: ceph-devel@vger.kernel.org
cc: netfs@lists.linux.dev
cc: linux-fsdevel@vger.kernel.org
cc: linux-mm@kvack.org
Link: https://lore.kernel.org/r/3575457.1722355300@warthog.procyon.org.uk/ [1]
Link: https://lore.kernel.org/r/1173209.1723152682@warthog.procyon.org.uk
Signed-off-by: Christian Brauner

netfs, ceph: Revert "netfs: Remove deprecated use of PG_private_2 as a second writeback flag"

2024-08-12T20:03:27+00:00

This reverts commit ae678317b95e760607c7b20b97c9cd4ca9ed6e1a.

Revert the patch that removes the deprecated use of PG_private_2 in
netfslib for the moment as Ceph is actually still using this to track
data copied to the cache.

Fixes: ae678317b95e ("netfs: Remove deprecated use of PG_private_2 as a second writeback flag")
Reported-by: Max Kellermann 
Signed-off-by: David Howells 
cc: Ilya Dryomov 
cc: Xiubo Li 
cc: Jeff Layton 
cc: Matthew Wilcox 
cc: ceph-devel@vger.kernel.org
cc: netfs@lists.linux.dev
cc: linux-fsdevel@vger.kernel.org
cc: linux-mm@kvack.org
https: //lore.kernel.org/r/3575457.1722355300@warthog.procyon.org.uk
Signed-off-by: Christian Brauner

ceph: force sending a cap update msg back to MDS for revoke op

2024-08-01T11:14:28+00:00

If a client sends out a cap update dropping caps with the prior 'seq'
just before an incoming cap revoke request, then the client may drop
the revoke because it believes it's already released the requested
capabilities.

This causes the MDS to wait indefinitely for the client to respond
to the revoke. It's therefore always a good idea to ack the cap
revoke request with the bumped up 'seq'.

Currently if the cap->issued equals to the newcaps the check_caps()
will do nothing, we should force flush the caps.

Cc: stable@vger.kernel.org
Link: https://tracker.ceph.com/issues/61782
Signed-off-by: Xiubo Li 
Reviewed-by: Venky Shankar 
Signed-off-by: Ilya Dryomov

Merge tag 'ceph-for-6.11-rc1' of https://github.com/ceph/ceph-client

2024-07-26T17:34:42+00:00

Pull ceph updates from Ilya Dryomov:
 "A small patchset to address bogus I/O errors and ultimately an
  assertion failure in the face of watch errors with -o exclusive
  mappings in RBD marked for stable and some assorted CephFS fixes"

* tag 'ceph-for-6.11-rc1' of https://github.com/ceph/ceph-client:
  rbd: don't assume rbd_is_lock_owner() for exclusive mappings
  rbd: don't assume RBD_LOCK_STATE_LOCKED for exclusive mappings
  rbd: rename RBD_LOCK_STATE_RELEASING and releasing_wait
  ceph: fix incorrect kmalloc size of pagevec mempool
  ceph: periodically flush the cap releases
  ceph: convert comma to semicolon in __ceph_dentry_dir_lease_touch()
  ceph: use cap_wait_list only if debugfs is enabled

ceph: fix incorrect kmalloc size of pagevec mempool

2024-07-23T08:01:57+00:00

The kmalloc size of pagevec mempool is incorrectly calculated.
It misses the size of page pointer and only accounts the number for the array.

Fixes: a0102bda5bc0 ("ceph: move sb->wb_pagevec_pool to be a global mempool")
Signed-off-by: ethanwu 
Reviewed-by: Xiubo Li 
Signed-off-by: Ilya Dryomov

ceph: periodically flush the cap releases

2024-07-23T08:01:57+00:00

The MDS could be waiting the caps releases infinitely in some corner
case and then reporting the caps revoke stuck warning. To fix this
we should periodically flush the cap releases.

Link: https://tracker.ceph.com/issues/57244
Signed-off-by: Xiubo Li 
Reviewed-by: Venky Shankar 
Signed-off-by: Ilya Dryomov

ceph: convert comma to semicolon in __ceph_dentry_dir_lease_touch()

2024-07-23T08:01:57+00:00

Replace a comma between expression statements by a semicolon.

Signed-off-by: Chen Ni 
Reviewed-by: Xiubo Li 
Signed-off-by: Ilya Dryomov