Pull misc vfs updates from Christian Brauner:
"Features:
- Add CONFIG_DEBUG_VFS infrastucture:
- Catch invalid modes in open
- Use the new debug macros in inode_set_cached_link()
- Use debug-only asserts around fd allocation and install
- Place f_ref to 3rd cache line in struct file to resolve false
sharing
Cleanups:
- Start using anon_inode_getfile_fmode() helper in various places
- Don't take f_lock during SEEK_CUR if exclusion is guaranteed by
f_pos_lock
- Add unlikely() to kcmp()
- Remove legacy ->remount_fs method from ecryptfs after port to the
new mount api
- Remove invalidate_inodes() in favour of evict_inodes()
- Simplify ep_busy_loopER by removing unused argument
- Avoid mmap sem relocks when coredumping with many missing pages
- Inline getname()
- Inline new_inode_pseudo() and de-staticize alloc_inode()
- Dodge an atomic in putname if ref == 1
- Consistently deref the files table with rcu_dereference_raw()
- Dedup handling of struct filename init and refcounts bumps
- Use wq_has_sleeper() in end_dir_add()
- Drop the lock trip around I_NEW wake up in evict()
- Load the ->i_sb pointer once in inode_sb_list_{add,del}
- Predict not reaching the limit in alloc_empty_file()
- Tidy up do_sys_openat2() with likely/unlikely
- Call inode_sb_list_add() outside of inode hash lock
- Sort out fd allocation vs dup2 race commentary
- Turn page_offset() into a wrapper around folio_pos()
- Remove locking in exportfs around ->get_parent() call
- try_lookup_one_len() does not need any locks in autofs
- Fix return type of several functions from long to int in open
- Fix return type of several functions from long to int in ioctls
Fixes:
- Fix watch queue accounting mismatch"
* tag 'vfs-6.15-rc1.misc' of git://git.kernel.org/pub/scm/linux/kernel/git/vfs/vfs: (30 commits)
fs: sort out fd allocation vs dup2 race commentary, take 2
fs: call inode_sb_list_add() outside of inode hash lock
fs: tidy up do_sys_openat2() with likely/unlikely
fs: predict not reaching the limit in alloc_empty_file()
fs: load the ->i_sb pointer once in inode_sb_list_{add,del}
fs: drop the lock trip around I_NEW wake up in evict()
fs: use wq_has_sleeper() in end_dir_add()
VFS/autofs: try_lookup_one_len() does not need any locks
fs: dedup handling of struct filename init and refcounts bumps
fs: consistently deref the files table with rcu_dereference_raw()
exportfs: remove locking around ->get_parent() call.
fs: use debug-only asserts around fd allocation and install
fs: dodge an atomic in putname if ref == 1
vfs: Remove invalidate_inodes()
ecryptfs: remove NULL remount_fs from super_operations
watch_queue: fix pipe accounting mismatch
fs: place f_ref to 3rd cache line in struct file to resolve false sharing
epoll: simplify ep_busy_loop by removing always 0 argument
fs: Turn page_offset() into a wrapper around folio_pos()
kcmp: improve performance adding an unlikely hint to task comparisons
...
The function can be replaced by evict_inodes. The only difference is that evict_inodes() skips the inodes with positive refcount without touching ->i_lock, but they are equivalent as evict_inodes() repeats the refcount check after having grabbed ->i_lock. Signed-off-by: Jan Kara <jack@suse.cz> Link: https://lore.kernel.org/r/20250307144318.28120-2-jack@suse.cz Signed-off-by: Christian Brauner <brauner@kernel.org>
Remove reconfigure_single, mount_single, and compare_single now that no users remain. Signed-off-by: Eric Sandeen <sandeen@redhat.com> Link: https://lore.kernel.org/r/20250205213931.74614-5-sandeen@redhat.com Signed-off-by: Christian Brauner <brauner@kernel.org>
As of now during link list corruption it prints about cluprit address and its wrong value, but sometime it is not enough to catch the actual issue point. If it prints allocation and free path of that corrupted node, it will be a lot easier to find and fix the issues. Adding the same information when data mismatch is found in link list debug data: [ 14.243055] slab kmalloc-32 start ffff0000cda19320 data offset 32 pointer offset 8 size 32 allocated at add_to_list+0x28/0xb0 [ 14.245259] __kmalloc_cache_noprof+0x1c4/0x358 [ 14.245572] add_to_list+0x28/0xb0 ... [ 14.248632] do_el0_svc_compat+0x1c/0x34 [ 14.249018] el0_svc_compat+0x2c/0x80 [ 14.249244] Free path: [ 14.249410] kfree+0x24c/0x2f0 [ 14.249724] do_force_corruption+0xbc/0x100 ... [ 14.252266] el0_svc_common.constprop.0+0x40/0xe0 [ 14.252540] do_el0_svc_compat+0x1c/0x34 [ 14.252763] el0_svc_compat+0x2c/0x80 [ 14.253071] ------------[ cut here ]------------ [ 14.253303] list_del corruption. next->prev should be ffff0000cda192a8, but was 6b6b6b6b6b6b6b6b. (next=ffff0000cda19348) [ 14.254255] WARNING: CPU: 3 PID: 84 at lib/list_debug.c:65 __list_del_entry_valid_or_report+0x158/0x164 Moved prototype of mem_dump_obj() to bug.h, as mm.h can not be included in bug.h. Link: https://lkml.kernel.org/r/20241230101043.53773-1-maninder1.s@samsung.com Signed-off-by: Maninder Singh <maninder1.s@samsung.com> Acked-by: Jan Kara <jack@suse.cz> Cc: Al Viro <viro@zeniv.linux.org.uk> Cc: Christian Brauner <brauner@kernel.org> Cc: Marco Elver <elver@google.com> Cc: Rohit Thapliyal <r.thapliyal@samsung.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
As Allison reported [1], currently get_tree_bdev() will store "Can't lookup blockdev" error message. Although it makes sense for pure bdev-based fses, this message may mislead users who try to use EROFS file-backed mounts since get_tree_nodev() is used as a fallback then. Add get_tree_bdev_flags() to specify extensible flags [2] and GET_TREE_BDEV_QUIET_LOOKUP to silence "Can't lookup blockdev" message since it's misleading to EROFS file-backed mounts now. [1] https://lore.kernel.org/r/CAOYeF9VQ8jKVmpy5Zy9DNhO6xmWSKMB-DO8yvBB0XvBE7=3Ugg@mail.gmail.com [2] https://lore.kernel.org/r/ZwUkJEtwIpUA4qMz@infradead.org Suggested-by: Christoph Hellwig <hch@infradead.org> Signed-off-by: Gao Xiang <hsiangkao@linux.alibaba.com> Link: https://lore.kernel.org/r/20241009033151.2334888-1-hsiangkao@linux.alibaba.com Reviewed-by: Christoph Hellwig <hch@lst.de> Reviewed-by: Jan Kara <jack@suse.cz> Signed-off-by: Christian Brauner <brauner@kernel.org>
Pull misc vfs updates from Christian Brauner:
"This contains the usual pile of misc updates:
Features:
- Add F_CREATED_QUERY fcntl() that allows userspace to query whether
a file was actually created. Often userspace wants to know whether
an O_CREATE request did actually create a file without using
O_EXCL. The current logic is that to first attempts to open the
file without O_CREAT | O_EXCL and if ENOENT is returned userspace
tries again with both flags. If that succeeds all is well. If it
now reports EEXIST it retries.
That works fairly well but some corner cases make this more
involved. If this operates on a dangling symlink the first openat()
without O_CREAT | O_EXCL will return ENOENT but the second openat()
with O_CREAT | O_EXCL will fail with EEXIST.
The reason is that openat() without O_CREAT | O_EXCL follows the
symlink while O_CREAT | O_EXCL doesn't for security reasons. So
it's not something we can really change unless we add an explicit
opt-in via O_FOLLOW which seems really ugly.
All available workarounds are really nasty (fanotify, bpf lsm etc)
so add a simple fcntl().
- Try an opportunistic lookup for O_CREAT. Today, when opening a file
we'll typically do a fast lookup, but if O_CREAT is set, the kernel
always takes the exclusive inode lock. This was likely done with
the expectation that O_CREAT means that we always expect to do the
create, but that's often not the case. Many programs set O_CREAT
even in scenarios where the file already exists (see related
F_CREATED_QUERY patch motivation above).
The series contained in the pr rearranges the pathwalk-for-open
code to also attempt a fast_lookup in certain O_CREAT cases. If a
positive dentry is found, the inode_lock can be avoided altogether
and it can stay in rcuwalk mode for the last step_into.
- Expose the 64 bit mount id via name_to_handle_at()
Now that we provide a unique 64-bit mount ID interface in statx(2),
we can now provide a race-free way for name_to_handle_at(2) to
provide a file handle and corresponding mount without needing to
worry about racing with /proc/mountinfo parsing or having to open a
file just to do statx(2).
While this is not necessary if you are using AT_EMPTY_PATH and
don't care about an extra statx(2) call, users that pass full paths
into name_to_handle_at(2) need to know which mount the file handle
comes from (to make sure they don't try to open_by_handle_at a file
handle from a different filesystem) and switching to AT_EMPTY_PATH
would require allocating a file for every name_to_handle_at(2) call
- Add a per dentry expire timeout to autofs
There are two fairly well known automounter map formats, the autofs
format and the amd format (more or less System V and Berkley).
Some time ago Linux autofs added an amd map format parser that
implemented a fair amount of the amd functionality. This was done
within the autofs infrastructure and some functionality wasn't
implemented because it either didn't make sense or required extra
kernel changes. The idea was to restrict changes to be within the
existing autofs functionality as much as possible and leave changes
with a wider scope to be considered later.
One of these changes is implementing the amd options:
1) "unmount", expire this mount according to a timeout (same as
the current autofs default).
2) "nounmount", don't expire this mount (same as setting the
autofs timeout to 0 except only for this specific mount) .
3) "utimeout=<seconds>", expire this mount using the specified
timeout (again same as setting the autofs timeout but only for
this mount)
To implement these options per-dentry expire timeouts need to be
implemented for autofs indirect mounts. This is because all map
keys (mounts) for autofs indirect mounts use an expire timeout
stored in the autofs mount super block info. structure and all
indirect mounts use the same expire timeout.
Fixes:
- Fix missing fput for FSCONFIG_SET_FD in autofs
- Use param->file for FSCONFIG_SET_FD in coda
- Delete the 'fs/netfs' proc subtreee when netfs module exits
- Make sure that struct uid_gid_map fits into a single cacheline
- Don't flush in-flight wb switches for superblocks without cgroup
writeback
- Correcting the idmapping mount example in the idmapping
documentation
- Fix a race between evice_inodes() and find_inode() and iput()
- Refine the show_inode_state() macro definition in writeback code
- Prevent dump_mapping() from accessing invalid dentry.d_name.name
- Show actual source for debugfs in /proc/mounts
- Annotate data-race of busy_poll_usecs in eventpoll
- Don't WARN for racy path_noexec check in exec code
- Handle OOM on mnt_warn_timestamp_expiry()
- Fix some spelling in the iomap design documentation
- Fix typo in procfs comment
- Fix typo in fs/namespace.c comment
Cleanups:
- Add the VFS git tree to the MAINTAINERS file
- Move FMODE_UNSIGNED_OFFSET to fop_flags freeing up another f_mode
bit in struct file bringing us to 5 free f_mode bits
- Remove the __I_DIO_WAKEUP bit from i_state flags as we can simplify
the wait mechanism
- Remove the unused path_put_init() helper
- Replace a __u32 with u32 for s_fsnotify_mask as __u32 is uapi
specific
- Replace the unsigned long i_state member with a u32 i_state member
in struct inode freeing up 4 bytes in struct inode. Instead of
using the bit based wait apis we're now using the var event apis
and using the individual bytes of the i_state member to wait on
state changes
- Explain how per-syscall AT_* flags should be allocated
- Use in_group_or_capable() helper to simplify the posix acl mode
update code
- Switch to LIST_HEAD() in fsync_buffers_list() to simplify the code
- Removed comment about d_rcu_to_refcount() as that function doesn't
exist anymore
- Add kernel documentation for lookup_fast()
- Don't re-zero evenpoll fields
- Remove outdated comment after close_fd()
- Fix imprecise wording in comment about the pipe filesystem
- Drop GFP_NOFAIL mode from alloc_page_buffers
- Missing blank line warnings and struct declaration improved in
file_table
- Annotate struct poll_list with __counted_by()
- Remove the unused read parameter in percpu-rwsem
- Remove linux/prefetch.h include from direct-io code
- Use kmemdup_array instead of kmemdup for multiple allocation in
mnt_idmapping code
- Remove unused mnt_cursor_del() declaration
Performance tweaks:
- Dodge smp_mb in break_lease and break_deleg in the common case
- Only read fops once in fops_{get,put}()
- Use RCU in ilookup()
- Elide smp_mb in iversion handling in the common case
- Drop one lock trip in evict()"
* tag 'vfs-6.12.misc' of gitolite.kernel.org:pub/scm/linux/kernel/git/vfs/vfs: (58 commits)
uidgid: make sure we fit into one cacheline
proc: Fix typo in the comment
fs/pipe: Correct imprecise wording in comment
fhandle: expose u64 mount id to name_to_handle_at(2)
uapi: explain how per-syscall AT_* flags should be allocated
fs: drop GFP_NOFAIL mode from alloc_page_buffers
writeback: Refine the show_inode_state() macro definition
fs/inode: Prevent dump_mapping() accessing invalid dentry.d_name.name
mnt_idmapping: Use kmemdup_array instead of kmemdup for multiple allocation
netfs: Delete subtree of 'fs/netfs' when netfs module exits
fs: use LIST_HEAD() to simplify code
inode: make i_state a u32
inode: port __I_LRU_ISOLATING to var event
vfs: fix race between evice_inodes() and find_inode()&iput()
inode: port __I_NEW to var event
inode: port __I_SYNC to var event
fs: reorder i_state bits
fs: add i_state helpers
MAINTAINERS: add the VFS git tree
fs: s/__u32/u32/ for s_fsnotify_mask
...
seeing an odd bug where we fail to correctly return an error from .get_tree(): https://syzkaller.appspot.com/bug?extid=c0360e8367d6d8d04a66 we need to be able to distinguish between accidently returning a positive error (as implied by the log) and no error. Cc: David Howells <dhowells@redhat.com> Signed-off-by: Kent Overstreet <kent.overstreet@linux.dev>
In the function percpu_rwsem_release, the parameter `read` is unused, so remove it. Signed-off-by: Wang Long <w@laoqinren.net> Link: https://lore.kernel.org/r/20240802091901.2546797-1-w@laoqinren.net Reviewed-by: Jan Kara <jack@suse.cz> Signed-off-by: Christian Brauner <brauner@kernel.org>
When deactivating any type of superblock, it had to wait for the in-flight wb switches to be completed. wb switches are executed in inode_switch_wbs_work_fn() which needs to acquire the wb_switch_rwsem and races against sync_inodes_sb(). If there are too much dirty data in the superblock, the waiting time may increase significantly. For superblocks without cgroup writeback such as tmpfs, they have nothing to do with the wb swithes, so the flushing can be avoided. Signed-off-by: Haifeng Xu <haifeng.xu@shopee.com> Link: https://lore.kernel.org/r/20240726030525.180330-1-haifeng.xu@shopee.com Reviewed-by: Jan Kara <jack@suse.cz> Suggested-by: Jan Kara <jack@suse.cz> Signed-off-by: Christian Brauner <brauner@kernel.org>
Christian noticed that it is possible for a privileged user to mount
most filesystems with a non-initial user namespace in sb->s_user_ns.
When fsopen() is called in a non-init namespace the caller's namespace
is recorded in fs_context->user_ns. If the returned file descriptor is
then passed to a process priviliged in init_user_ns, that process can
call fsconfig(fd_fs, FSCONFIG_CMD_CREATE), creating a new superblock
with sb->s_user_ns set to the namespace of the process which called
fsopen().
This is problematic. We cannot assume that any filesystem which does not
set FS_USERNS_MOUNT has been written with a non-initial s_user_ns in
mind, increasing the risk for bugs and security issues.
Prevent this by returning EPERM from sget_fc() when FS_USERNS_MOUNT is
not set for the filesystem and a non-initial user namespace will be
used. sget() does not need to be updated as it always uses the user
namespace of the current context, or the initial user namespace if
SB_SUBMOUNT is set.
Fixes: cb50b348c71f ("convenience helpers: vfs_get_super() and sget_fc()")
Reported-by: Christian Brauner <brauner@kernel.org>
Signed-off-by: Seth Forshee (DigitalOcean) <sforshee@kernel.org>
Link: https://lore.kernel.org/r/20240724-s_user_ns-fix-v1-1-895d07c94701@kernel.org
Reviewed-by: Alexander Mikhalitsyn <aleksandr.mikhalitsyn@canonical.com>
Signed-off-by: Christian Brauner <brauner@kernel.org>