Commit Graph

191 Commits

Author SHA1 Message Date
Colin Walters
0c8c88b8eb ovl: fix verity lazy-load guard broken by fsverity_active() semantic change
Commit f77f281b61 ("fsverity: use a hashtable to find the
fsverity_info") made fsverity_active() check whether the inode has the
verity flag, rather than whether the inode's fsverity_info is loaded.
This broke ovl_ensure_verity_loaded(), which wants to load the
fsverity_info for any verity inodes that haven't had it loaded yet.

Therefore, to check that the fsverity_info hasn't yet been loaded, use
fsverity_get_info(inode) == NULL instead of !fsverity_active(inode).

Also, since fsverity_get_info() now involves a hash table lookup, put
the more lightweight IS_VERITY() flag check first.

Fixes: f77f281b61 ("fsverity: use a hashtable to find the fsverity_info")
Cc: stable@vger.kernel.org
Link: https://github.com/bootc-dev/bootc/issues/2174
Signed-off-by: Colin Walters <walters@verbum.org>
Acked-by: Amir Goldstein <amir73il@gmail.com>
Link: https://patch.msgid.link/20260505224257.23213-1-ebiggers@kernel.org
Signed-off-by: Eric Biggers <ebiggers@kernel.org>
2026-05-06 08:37:30 -07:00
Linus Torvalds
b7d74ea0fd vfs-7.1-rc1.kino
Please consider pulling these changes from the signed vfs-7.1-rc1.kino tag.
 
 Thanks!
 Christian
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Merge tag 'vfs-7.1-rc1.kino' of git://git.kernel.org/pub/scm/linux/kernel/git/vfs/vfs

Pull vfs i_ino updates from Christian Brauner:
 "For historical reasons, the inode->i_ino field is an unsigned long,
  which means that it's 32 bits on 32 bit architectures. This has caused
  a number of filesystems to implement hacks to hash a 64-bit identifier
  into a 32-bit field, and deprives us of a universal identifier field
  for an inode.

  This changes the inode->i_ino field from an unsigned long to a u64.
  This shouldn't make any material difference on 64-bit hosts, but
  32-bit hosts will see struct inode grow by at least 4 bytes. This
  could have effects on slabcache sizes and field alignment.

  The bulk of the changes are to format strings and tracepoints, since
  the kernel itself doesn't care that much about the i_ino field. The
  first patch changes some vfs function arguments, so check that one out
  carefully.

  With this change, we may be able to shrink some inode structures. For
  instance, struct nfs_inode has a fileid field that holds the 64-bit
  inode number. With this set of changes, that field could be
  eliminated. I'd rather leave that sort of cleanups for later just to
  keep this simple"

* tag 'vfs-7.1-rc1.kino' of git://git.kernel.org/pub/scm/linux/kernel/git/vfs/vfs:
  nilfs2: fix 64-bit division operations in nilfs_bmap_find_target_in_group()
  EVM: add comment describing why ino field is still unsigned long
  vfs: remove externs from fs.h on functions modified by i_ino widening
  treewide: fix missed i_ino format specifier conversions
  ext4: fix signed format specifier in ext4_load_inode trace event
  treewide: change inode->i_ino from unsigned long to u64
  nilfs2: widen trace event i_ino fields to u64
  f2fs: widen trace event i_ino fields to u64
  ext4: widen trace event i_ino fields to u64
  zonefs: widen trace event i_ino fields to u64
  hugetlbfs: widen trace event i_ino fields to u64
  ext2: widen trace event i_ino fields to u64
  cachefiles: widen trace event i_ino fields to u64
  vfs: widen trace event i_ino fields to u64
  net: change sock.sk_ino and sock_i_ino() to u64
  audit: widen ino fields to u64
  vfs: widen inode hash/lookup functions to u64
2026-04-13 12:19:01 -07:00
Linus Torvalds
3383589700 vfs-7.1-rc1.directory
Please consider pulling these changes from the signed vfs-7.1-rc1.directory tag.
 
 Thanks!
 Christian
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Merge tag 'vfs-7.1-rc1.directory' of git://git.kernel.org/pub/scm/linux/kernel/git/vfs/vfs

Pull vfs directory updates from Christian Brauner:
 "Recently 'start_creating', 'start_removing', 'start_renaming' and
  related interfaces were added which combine the locking and the
  lookup.

  At that time many callers were changed to use the new interfaces.
  However there are still an assortment of places out side of the core
  vfs where the directory is locked explictly, whether with inode_lock()
  or lock_rename() or similar. These were missed in the first pass for
  an assortment of uninteresting reasons.

  This addresses the remaining places where explicit locking is used,
  and changes them to use the new interfaces, or otherwise removes the
  explicit locking.

  The biggest changes are in overlayfs. The other changes are quite
  simple, though maybe the cachefiles changes is the least simple of
  those"

* tag 'vfs-7.1-rc1.directory' of git://git.kernel.org/pub/scm/linux/kernel/git/vfs/vfs:
  VFS: unexport lock_rename(), lock_rename_child(), unlock_rename()
  ovl: remove ovl_lock_rename_workdir()
  ovl: use is_subdir() for testing if one thing is a subdir of another
  ovl: change ovl_create_real() to get a new lock when re-opening created file.
  ovl: pass name buffer to ovl_start_creating_temp()
  cachefiles: change cachefiles_bury_object to use start_renaming_dentry()
  ovl: Simplify ovl_lookup_real_one()
  VFS: make lookup_one_qstr_excl() static.
  nfsd: switch purge_old() to use start_removing_noperm()
  selinux: Use simple_start_creating() / simple_done_creating()
  Apparmor: Use simple_start_creating() / simple_done_creating()
  libfs: change simple_done_creating() to use end_creating()
  VFS: move the start_dirop() kerndoc comment to before start_dirop()
  fs/proc: Don't lock root inode when creating "self" and "thread-self"
  VFS: note error returns in documentation for various lookup functions
2026-04-13 10:24:33 -07:00
Amir Goldstein
53a7c171e9 ovl: fix wrong detection of 32bit inode numbers
The implicit FILEID_INO32_GEN encoder was changed to be explicit,
so we need to fix the detection.

When mounting overlayfs with upperdir and lowerdir on different ext4
filesystems, the expected kmsg log is:

  overlayfs: "xino" feature enabled using 32 upper inode bits.

But instead, since the regressing commit, the kmsg log was:

  overlayfs: "xino" feature enabled using 2 upper inode bits.

Fixes: e21fc2038c ("exportfs: make ->encode_fh() a mandatory method for NFS export")
Cc: stable@vger.kernel.org # v6.7+
Signed-off-by: Amir Goldstein <amir73il@gmail.com>
2026-03-24 16:17:26 +01:00
NeilBrown
54d7ea7324
ovl: remove ovl_lock_rename_workdir()
This function is unused since
   Commit 833d2b3a07 ("Add start_renaming_two_dentries()")

Reviewed-by: Amir Goldstein <amir73il@gmail.com>
Reviewed-by: Jeff Layton <jlayton@kernel.org>
Signed-off-by: NeilBrown <neil@brown.name>
Link: https://patch.msgid.link/20260224222542.3458677-15-neilb@ownmail.net
Signed-off-by: Christian Brauner <brauner@kernel.org>
2026-03-09 09:43:04 +01:00
Jeff Layton
0b2600f81c
treewide: change inode->i_ino from unsigned long to u64
On 32-bit architectures, unsigned long is only 32 bits wide, which
causes 64-bit inode numbers to be silently truncated. Several
filesystems (NFS, XFS, BTRFS, etc.) can generate inode numbers that
exceed 32 bits, and this truncation can lead to inode number collisions
and other subtle bugs on 32-bit systems.

Change the type of inode->i_ino from unsigned long to u64 to ensure that
inode numbers are always represented as 64-bit values regardless of
architecture. Update all format specifiers treewide from %lu/%lx to
%llu/%llx to match the new type, along with corresponding local variable
types.

This is the bulk treewide conversion. Earlier patches in this series
handled trace events separately to allow trace field reordering for
better struct packing on 32-bit.

Signed-off-by: Jeff Layton <jlayton@kernel.org>
Link: https://patch.msgid.link/20260304-iino-u64-v3-12-2257ad83d372@kernel.org
Acked-by: Damien Le Moal <dlemoal@kernel.org>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Jan Kara <jack@suse.cz>
Reviewed-by: Chuck Lever <chuck.lever@oracle.com>
Signed-off-by: Christian Brauner <brauner@kernel.org>
2026-03-06 14:31:28 +01:00
Linus Torvalds
323bbfcf1e Convert 'alloc_flex' family to use the new default GFP_KERNEL argument
This is the exact same thing as the 'alloc_obj()' version, only much
smaller because there are a lot fewer users of the *alloc_flex()
interface.

As with alloc_obj() version, this was done entirely with mindless brute
force, using the same script, except using 'flex' in the pattern rather
than 'objs*'.

Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2026-02-21 17:09:51 -08:00
Linus Torvalds
bf4afc53b7 Convert 'alloc_obj' family to use the new default GFP_KERNEL argument
This was done entirely with mindless brute force, using

    git grep -l '\<k[vmz]*alloc_objs*(.*, GFP_KERNEL)' |
        xargs sed -i 's/\(alloc_objs*(.*\), GFP_KERNEL)/\1)/'

to convert the new alloc_obj() users that had a simple GFP_KERNEL
argument to just drop that argument.

Note that due to the extreme simplicity of the scripting, any slightly
more complex cases spread over multiple lines would not be triggered:
they definitely exist, but this covers the vast bulk of the cases, and
the resulting diff is also then easier to check automatically.

For the same reason the 'flex' versions will be done as a separate
conversion.

Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2026-02-21 17:09:51 -08:00
Kees Cook
69050f8d6d treewide: Replace kmalloc with kmalloc_obj for non-scalar types
This is the result of running the Coccinelle script from
scripts/coccinelle/api/kmalloc_objs.cocci. The script is designed to
avoid scalar types (which need careful case-by-case checking), and
instead replace kmalloc-family calls that allocate struct or union
object instances:

Single allocations:	kmalloc(sizeof(TYPE), ...)
are replaced with:	kmalloc_obj(TYPE, ...)

Array allocations:	kmalloc_array(COUNT, sizeof(TYPE), ...)
are replaced with:	kmalloc_objs(TYPE, COUNT, ...)

Flex array allocations:	kmalloc(struct_size(PTR, FAM, COUNT), ...)
are replaced with:	kmalloc_flex(*PTR, FAM, COUNT, ...)

(where TYPE may also be *VAR)

The resulting allocations no longer return "void *", instead returning
"TYPE *".

Signed-off-by: Kees Cook <kees@kernel.org>
2026-02-21 01:02:28 -08:00
Linus Torvalds
d0deeb803c vfs-6.19-rc1.ovl
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Merge tag 'vfs-6.19-rc1.ovl' of git://git.kernel.org/pub/scm/linux/kernel/git/vfs/vfs

Pull overlayfs cred guard conversion from Christian Brauner:
 "This converts all of overlayfs to use credential guards, eliminating
  manual credential management throughout the filesystem.

  Credential guard conversion:

   - Convert all of overlayfs to use credential guards, replacing the
     manual ovl_override_creds()/ovl_revert_creds() pattern with scoped
     guards.

     This makes credential handling visually explicit and eliminates a
     class of potential bugs from mismatched override/revert calls.

     (1) Basic credential guard (with_ovl_creds)
     (2) Creator credential guard (ovl_override_creator_creds):

         Introduced a specialized guard for file creation operations
         that handles the two-phase credential override (mounter
         credentials, then fs{g,u}id override). The new pattern is much
         clearer:

         with_ovl_creds(dentry->d_sb) {
                 scoped_class(prepare_creds_ovl, cred, dentry, inode, mode) {
                         if (IS_ERR(cred))
                                 return PTR_ERR(cred);
                         /* creation operations */
                 }
         }

     (3) Copy-up credential guard (ovl_cu_creds):

         Introduced a specialized guard for copy-up operations,
         simplifying the previous struct ovl_cu_creds helper and
         associated functions.

         Ported ovl_copy_up_workdir() and ovl_copy_up_tmpfile() to this
         pattern.

  Cleanups:

   - Remove ovl_revert_creds() after all callers converted to guards

   - Remove struct ovl_cu_creds and associated functions

   - Drop ovl_setup_cred_for_create() after conversion

   - Refactor ovl_fill_super(), ovl_lookup(), ovl_iterate(),
     ovl_rename() for cleaner credential guard scope

   - Introduce struct ovl_renamedata to simplify rename handling

   - Don't override credentials for ovl_check_whiteouts() (unnecessary)

   - Remove unneeded semicolon"

* tag 'vfs-6.19-rc1.ovl' of git://git.kernel.org/pub/scm/linux/kernel/git/vfs/vfs: (54 commits)
  ovl: remove unneeded semicolon
  ovl: remove struct ovl_cu_creds and associated functions
  ovl: port ovl_copy_up_tmpfile() to cred guard
  ovl: mark *_cu_creds() as unused temporarily
  ovl: port ovl_copy_up_workdir() to cred guard
  ovl: add copy up credential guard
  ovl: drop ovl_setup_cred_for_create()
  ovl: port ovl_create_or_link() to new ovl_override_creator_creds cleanup guard
  ovl: mark ovl_setup_cred_for_create() as unused temporarily
  ovl: reflow ovl_create_or_link()
  ovl: port ovl_create_tmpfile() to new ovl_override_creator_creds cleanup guard
  ovl: add ovl_override_creator_creds cred guard
  ovl: remove ovl_revert_creds()
  ovl: port ovl_fill_super() to cred guard
  ovl: refactor ovl_fill_super()
  ovl: port ovl_lower_positive() to cred guard
  ovl: port ovl_lookup() to cred guard
  ovl: refactor ovl_lookup()
  ovl: port ovl_copyfile() to cred guard
  ovl: port ovl_rename() to cred guard
  ...
2025-12-01 16:31:21 -08:00
Linus Torvalds
a8058f8442 vfs-6.19-rc1.directory.locking
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Merge tag 'vfs-6.19-rc1.directory.locking' of git://git.kernel.org/pub/scm/linux/kernel/git/vfs/vfs

Pull directory locking updates from Christian Brauner:
 "This contains the work to add centralized APIs for directory locking
  operations.

  This series is part of a larger effort to change directory operation
  locking to allow multiple concurrent operations in a directory. The
  ultimate goal is to lock the target dentry(s) rather than the whole
  parent directory.

  To help with changing the locking protocol, this series centralizes
  locking and lookup in new helper functions. The helpers establish a
  pattern where it is the dentry that is being locked and unlocked
  (currently the lock is held on dentry->d_parent->d_inode, but that can
  change in the future).

  This also changes vfs_mkdir() to unlock the parent on failure, as well
  as dput()ing the dentry. This allows end_creating() to only require
  the target dentry (which may be IS_ERR() after vfs_mkdir()), not the
  parent"

* tag 'vfs-6.19-rc1.directory.locking' of git://git.kernel.org/pub/scm/linux/kernel/git/vfs/vfs:
  nfsd: fix end_creating() conversion
  VFS: introduce end_creating_keep()
  VFS: change vfs_mkdir() to unlock on failure.
  ecryptfs: use new start_creating/start_removing APIs
  Add start_renaming_two_dentries()
  VFS/ovl/smb: introduce start_renaming_dentry()
  VFS/nfsd/ovl: introduce start_renaming() and end_renaming()
  VFS: add start_creating_killable() and start_removing_killable()
  VFS: introduce start_removing_dentry()
  smb/server: use end_removing_noperm for for target of smb2_create_link()
  VFS: introduce start_creating_noperm() and start_removing_noperm()
  VFS/nfsd/cachefiles/ovl: introduce start_removing() and end_removing()
  VFS/nfsd/cachefiles/ovl: add start_creating() and end_creating()
  VFS: tidy up do_unlinkat()
  VFS: introduce start_dirop() and end_dirop()
  debugfs: rename end_creating() to debugfs_end_creating()
2025-12-01 16:13:46 -08:00
Linus Torvalds
9368f0f941 vfs-6.19-rc1.inode
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Merge tag 'vfs-6.19-rc1.inode' of git://git.kernel.org/pub/scm/linux/kernel/git/vfs/vfs

Pull vfs inode updates from Christian Brauner:
 "Features:

   - Hide inode->i_state behind accessors. Open-coded accesses prevent
     asserting they are done correctly. One obvious aspect is locking,
     but significantly more can be checked. For example it can be
     detected when the code is clearing flags which are already missing,
     or is setting flags when it is illegal (e.g., I_FREEING when
     ->i_count > 0)

   - Provide accessors for ->i_state, converts all filesystems using
     coccinelle and manual conversions (btrfs, ceph, smb, f2fs, gfs2,
     overlayfs, nilfs2, xfs), and makes plain ->i_state access fail to
     compile

   - Rework I_NEW handling to operate without fences, simplifying the
     code after the accessor infrastructure is in place

  Cleanups:

   - Move wait_on_inode() from writeback.h to fs.h

   - Spell out fenced ->i_state accesses with explicit smp_wmb/smp_rmb
     for clarity

   - Cosmetic fixes to LRU handling

   - Push list presence check into inode_io_list_del()

   - Touch up predicts in __d_lookup_rcu()

   - ocfs2: retire ocfs2_drop_inode() and I_WILL_FREE usage

   - Assert on ->i_count in iput_final()

   - Assert ->i_lock held in __iget()

  Fixes:

   - Add missing fences to I_NEW handling"

* tag 'vfs-6.19-rc1.inode' of git://git.kernel.org/pub/scm/linux/kernel/git/vfs/vfs: (22 commits)
  dcache: touch up predicts in __d_lookup_rcu()
  fs: push list presence check into inode_io_list_del()
  fs: cosmetic fixes to lru handling
  fs: rework I_NEW handling to operate without fences
  fs: make plain ->i_state access fail to compile
  xfs: use the new ->i_state accessors
  nilfs2: use the new ->i_state accessors
  overlayfs: use the new ->i_state accessors
  gfs2: use the new ->i_state accessors
  f2fs: use the new ->i_state accessors
  smb: use the new ->i_state accessors
  ceph: use the new ->i_state accessors
  btrfs: use the new ->i_state accessors
  Manual conversion to use ->i_state accessors of all places not covered by coccinelle
  Coccinelle-based conversion to use ->i_state accessors
  fs: provide accessors for ->i_state
  fs: spell out fenced ->i_state accesses with explicit smp_wmb/smp_rmb
  fs: move wait_on_inode() from writeback.h to fs.h
  fs: add missing fences to I_NEW handling
  ocfs2: retire ocfs2_drop_inode() and I_WILL_FREE usage
  ...
2025-12-01 09:02:34 -08:00
NeilBrown
e9c70084a6
ovl: fail ovl_lock_rename_workdir() if either target is unhashed
As well as checking that the parent hasn't changed after getting the
lock we need to check that the dentry hasn't been unhashed.
Otherwise we might try to rename something that has been removed.

Reported-by: syzbot+bfc9a0ccf0de47d04e8c@syzkaller.appspotmail.com
Fixes: d2c995581c ("ovl: Call ovl_create_temp() without lock held.")
Signed-off-by: NeilBrown <neil@brown.name>
Link: https://patch.msgid.link/176429295510.634289.1552337113663461690@noble.neil.brown.name
Tested-by: syzbot+bfc9a0ccf0de47d04e8c@syzkaller.appspotmail.com
Reviewed-by: Amir Goldstein <amir73il@gmail.com>
Signed-off-by: Christian Brauner <brauner@kernel.org>
2025-11-28 10:42:32 +01:00
Christian Brauner
850e32512a
ovl: remove ovl_revert_creds()
The wrapper isn't needed anymore. Overlayfs completely relies on its
cleanup guard.

Link: https://patch.msgid.link/20251117-work-ovl-cred-guard-v4-42-b31603935724@kernel.org
Reviewed-by: Amir Goldstein <amir73il@gmail.com>
Signed-off-by: Christian Brauner <brauner@kernel.org>
2025-11-19 21:58:25 +01:00
Christian Brauner
9e5ec68f3a
ovl: port ovl_nlink_end() to cred guard
Use the scoped ovl cred guard.

Link: https://patch.msgid.link/20251117-work-ovl-cred-guard-v4-29-b31603935724@kernel.org
Reviewed-by: Amir Goldstein <amir73il@gmail.com>
Signed-off-by: Christian Brauner <brauner@kernel.org>
2025-11-19 21:58:23 +01:00
Christian Brauner
062c5b48d2
ovl: port ovl_nlink_start() to cred guard
Use the scoped ovl cred guard.

Link: https://patch.msgid.link/20251117-work-ovl-cred-guard-v4-28-b31603935724@kernel.org
Reviewed-by: Amir Goldstein <amir73il@gmail.com>
Signed-off-by: Christian Brauner <brauner@kernel.org>
2025-11-19 21:58:23 +01:00
NeilBrown
ac50950ca1
VFS/ovl/smb: introduce start_renaming_dentry()
Several callers perform a rename on a dentry they already have, and only
require lookup for the target name.  This includes smb/server and a few
different places in overlayfs.

start_renaming_dentry() performs the required lookup and takes the
required lock using lock_rename_child()

It is used in three places in overlayfs and in ksmbd_vfs_rename().

In the ksmbd case, the parent of the source is not important - the
source must be renamed from wherever it is.  So start_renaming_dentry()
allows rd->old_parent to be NULL and only checks it if it is non-NULL.
On success rd->old_parent will be the parent of old_dentry with an extra
reference taken.  Other start_renaming function also now take the extra
reference and end_renaming() now drops this reference as well.

ovl_lookup_temp(), ovl_parent_lock(), and ovl_parent_unlock() are
all removed as they are no longer needed.

OVL_TEMPNAME_SIZE and ovl_tempname() are now declared in overlayfs.h so
that ovl_check_rename_whiteout() can access them.

ovl_copy_up_workdir() now always cleans up on error.

Reviewed-by: Namjae Jeon <linkinjeon@kernel.org>
Reviewed-by: Amir Goldstein <amir73il@gmail.com>
Reviewed-by: Jeff Layton <jlayton@kernel.org>
Signed-off-by: NeilBrown <neil@brown.name>
Link: https://patch.msgid.link/20251113002050.676694-12-neilb@ownmail.net
Tested-by: syzbot@syzkaller.appspotmail.com
Signed-off-by: Christian Brauner <brauner@kernel.org>
2025-11-14 13:15:57 +01:00
Mateusz Guzik
ff175a4fc2
overlayfs: use the new ->i_state accessors
Change generated with coccinelle and fixed up by hand as appropriate.

Signed-off-by: Mateusz Guzik <mjguzik@gmail.com>
Signed-off-by: Christian Brauner <brauner@kernel.org>
2025-10-20 20:22:27 +02:00
Linus Torvalds
50647a1176 file->f_path constification
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
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Merge tag 'pull-f_path' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs

Pull file->f_path constification from Al Viro:
 "Only one thing was modifying ->f_path of an opened file - acct(2).

  Massaging that away and constifying a bunch of struct path * arguments
  in functions that might be given &file->f_path ends up with the
  situation where we can turn ->f_path into an anon union of const
  struct path f_path and struct path __f_path, the latter modified only
  in a few places in fs/{file_table,open,namei}.c, all for struct file
  instances that are yet to be opened"

* tag 'pull-f_path' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs: (23 commits)
  Have cc(1) catch attempts to modify ->f_path
  kernel/acct.c: saner struct file treatment
  configfs:get_target() - release path as soon as we grab configfs_item reference
  apparmor/af_unix: constify struct path * arguments
  ovl_is_real_file: constify realpath argument
  ovl_sync_file(): constify path argument
  ovl_lower_dir(): constify path argument
  ovl_get_verity_digest(): constify path argument
  ovl_validate_verity(): constify {meta,data}path arguments
  ovl_ensure_verity_loaded(): constify datapath argument
  ksmbd_vfs_set_init_posix_acl(): constify path argument
  ksmbd_vfs_inherit_posix_acl(): constify path argument
  ksmbd_vfs_kern_path_unlock(): constify path argument
  ksmbd_vfs_path_lookup_locked(): root_share_path can be const struct path *
  check_export(): constify path argument
  export_operations->open(): constify path argument
  rqst_exp_get_by_name(): constify path argument
  nfs: constify path argument of __vfs_getattr()
  bpf...d_path(): constify path argument
  done_path_create(): constify path argument
  ...
2025-10-03 16:32:36 -07:00
André Almeida
16754d61dc ovl: Support mounting case-insensitive enabled layers
Drop the restriction for casefold dentries lookup to enable support for
case-insensitive layers in overlayfs.

Support case-insensitive layers with the condition that they should be
uniformly enabled across the stack and (i.e. if the root mount dir has
casefold enabled, so should all the dirs bellow for every layer).

Reviewed-by: Amir Goldstein <amir73il@gmail.com>
Signed-off-by: André Almeida <andrealmeid@igalia.com>
Signed-off-by: Amir Goldstein <amir73il@gmail.com>
2025-09-23 12:29:36 +02:00
Al Viro
465309d63f ovl_get_verity_digest(): constify path argument
Reviewed-by: Christian Brauner <brauner@kernel.org>
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2025-09-15 21:17:09 -04:00
Al Viro
c93cd35374 ovl_validate_verity(): constify {meta,data}path arguments
Reviewed-by: Christian Brauner <brauner@kernel.org>
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2025-09-15 21:17:09 -04:00
Al Viro
7e978e8fb6 ovl_ensure_verity_loaded(): constify datapath argument
Reviewed-by: Christian Brauner <brauner@kernel.org>
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2025-09-15 21:17:09 -04:00
Amir Goldstein
e8bd877fb7 ovl: fix possible double unlink
commit 9d23967b18 ("ovl: simplify an error path in
ovl_copy_up_workdir()") introduced the helper ovl_cleanup_unlocked(),
which is later used in several following patches to re-acquire the parent
inode lock and unlink a dentry that was earlier found using lookup.
This helper was eventually renamed to ovl_cleanup().

The helper ovl_parent_lock() is used to re-acquire the parent inode lock.
After acquiring the parent inode lock, the helper verifies that the
dentry has not since been moved to another parent, but it failed to
verify that the dentry wasn't unlinked from the parent.

This means that now every call to ovl_cleanup() could potentially
race with another thread, unlinking the dentry to be cleaned up
underneath overlayfs and trigger a vfs assertion.

Reported-by: syzbot+ec9fab8b7f0386b98a17@syzkaller.appspotmail.com
Tested-by: syzbot+ec9fab8b7f0386b98a17@syzkaller.appspotmail.com
Fixes: 9d23967b18 ("ovl: simplify an error path in ovl_copy_up_workdir()")
Suggested-by: NeilBrown <neil@brown.name>
Signed-off-by: Amir Goldstein <amir73il@gmail.com>
2025-08-18 13:16:49 +02:00
Linus Torvalds
57fcb7d930 vfs-6.17-rc1.fileattr
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Merge tag 'vfs-6.17-rc1.fileattr' of git://git.kernel.org/pub/scm/linux/kernel/git/vfs/vfs

Pull fileattr updates from Christian Brauner:
 "This introduces the new file_getattr() and file_setattr() system calls
  after lengthy discussions.

  Both system calls serve as successors and extensible companions to
  the FS_IOC_FSGETXATTR and FS_IOC_FSSETXATTR system calls which have
  started to show their age in addition to being named in a way that
  makes it easy to conflate them with extended attribute related
  operations.

  These syscalls allow userspace to set filesystem inode attributes on
  special files. One of the usage examples is the XFS quota projects.

  XFS has project quotas which could be attached to a directory. All new
  inodes in these directories inherit project ID set on parent
  directory.

  The project is created from userspace by opening and calling
  FS_IOC_FSSETXATTR on each inode. This is not possible for special
  files such as FIFO, SOCK, BLK etc. Therefore, some inodes are left
  with empty project ID. Those inodes then are not shown in the quota
  accounting but still exist in the directory. This is not critical but
  in the case when special files are created in the directory with
  already existing project quota, these new inodes inherit extended
  attributes. This creates a mix of special files with and without
  attributes. Moreover, special files with attributes don't have a
  possibility to become clear or change the attributes. This, in turn,
  prevents userspace from re-creating quota project on these existing
  files.

  In addition, these new system calls allow the implementation of
  additional attributes that we couldn't or didn't want to fit into the
  legacy ioctls anymore"

* tag 'vfs-6.17-rc1.fileattr' of git://git.kernel.org/pub/scm/linux/kernel/git/vfs/vfs:
  fs: tighten a sanity check in file_attr_to_fileattr()
  tree-wide: s/struct fileattr/struct file_kattr/g
  fs: introduce file_getattr and file_setattr syscalls
  fs: prepare for extending file_get/setattr()
  fs: make vfs_fileattr_[get|set] return -EOPNOTSUPP
  selinux: implement inode_file_[g|s]etattr hooks
  lsm: introduce new hooks for setting/getting inode fsxattr
  fs: split fileattr related helpers into separate file
2025-07-28 15:24:14 -07:00
NeilBrown
fe4d3360f9
ovl: rename ovl_cleanup_unlocked() to ovl_cleanup()
The only remaining user of ovl_cleanup() is ovl_cleanup_locked(), so we
no longer need both.

This patch renames ovl_cleanup() to ovl_cleanup_locked() and makes it
static.
ovl_cleanup_unlocked() is renamed to ovl_cleanup().

Signed-off-by: NeilBrown <neil@brown.name>
Link: https://lore.kernel.org/20250716004725.1206467-22-neil@brown.name
Reviewed-by: Amir Goldstein <amir73il@gmail.com>
Signed-off-by: Christian Brauner <brauner@kernel.org>
2025-07-18 11:10:43 +02:00
NeilBrown
2fa14cf2dc
ovl: change ovl_cleanup_and_whiteout() to take rename lock as needed
Rather than locking the directory(s) before calling
ovl_cleanup_and_whiteout(), change it (and ovl_whiteout()) to do the
locking, so the locking can be fine grained as will be needed for
proposed locking changes.

Sometimes this is called to whiteout something in the index dir, in
which case only that dir must be locked.  In one case it is called on
something in an upperdir, so two directories must be locked.  We use
ovl_lock_rename_workdir() for this and remove the restriction that
upperdir cannot be indexdir - because now sometimes it is.

Reviewed-by: Amir Goldstein <amir73il@gmail.com>
Signed-off-by: NeilBrown <neil@brown.name>
Link: https://lore.kernel.org/20250716004725.1206467-18-neil@brown.name
Signed-off-by: Christian Brauner <brauner@kernel.org>
2025-07-18 11:10:42 +02:00
NeilBrown
8290fb412d
ovl: narrow locking in ovl_cleanup_index()
ovl_cleanup_index() takes a lock on the directory and then does a lookup
and possibly one of two different cleanups.
This patch narrows the locking to use the _unlocked() versions of the
lookup and one cleanup, and just takes the lock for the other cleanup.

A subsequent patch will take the lock into the cleanup.

Signed-off-by: NeilBrown <neil@brown.name>
Link: https://lore.kernel.org/20250716004725.1206467-12-neil@brown.name
Reviewed-by: Amir Goldstein <amir73il@gmail.com>
Signed-off-by: Christian Brauner <brauner@kernel.org>
2025-07-18 11:10:41 +02:00
NeilBrown
d2c995581c
ovl: Call ovl_create_temp() without lock held.
ovl currently locks a directory or two and then performs multiple actions
in one or both directories.  This is incompatible with proposed changes
which will lock just the dentry of objects being acted on.

This patch moves calls to ovl_create_temp() out of the locked regions and
has it take and release the relevant lock itself.

The lock that was taken before this function was called is now taken
after.  This means that any code between where the lock was taken and
ovl_create_temp() is now unlocked.  This necessitates the use of
ovl_cleanup_unlocked() and the creation of ovl_lookup_upper_unlocked().
These will be used more widely in future patches.

Now that the file is created before the lock is taken for rename, we
need to ensure the parent wasn't changed before the lock was gained.
ovl_lock_rename_workdir() is changed to optionally receive the dentries
that will be involved in the rename.  If either is present but has the
wrong parent, an error is returned.

Reviewed-by: Amir Goldstein <amir73il@gmail.com>
Signed-off-by: NeilBrown <neil@brown.name>
Link: https://lore.kernel.org/20250716004725.1206467-4-neil@brown.name
Signed-off-by: Christian Brauner <brauner@kernel.org>
2025-07-18 11:10:40 +02:00
NeilBrown
9d23967b18
ovl: simplify an error path in ovl_copy_up_workdir()
If ovl_copy_up_data() fails the error is not immediately handled but the
code continues on to call ovl_start_write() and lock_rename(),
presumably because both of these locks are needed for the cleanup.
Only then (if the lock was successful) is the error checked.

This makes the code a little hard to follow and could be fragile.

This patch changes to handle the error after the ovl_start_write()
(which cannot fail, so there aren't multiple errors to deail with).  A
new ovl_cleanup_unlocked() is created which takes the required directory
lock.  This will be used extensively in later patches.

In general we need to check the parent is still correct after taking the
lock (as ovl_copy_up_workdir() does after a successful lock_rename()) so
that is included in ovl_cleanup_unlocked() using new ovl_parent_lock()
and ovl_parent_unlock() calls (it is planned to move this API into VFS code
eventually, though in a slightly different form).

Signed-off-by: NeilBrown <neil@brown.name>
Link: https://lore.kernel.org/20250716004725.1206467-2-neil@brown.name
Reviewed-by: Amir Goldstein <amir73il@gmail.com>
Signed-off-by: Christian Brauner <brauner@kernel.org>
2025-07-18 11:10:40 +02:00
Amir Goldstein
083957f961
ovl: support layers on case-folding capable filesystems
Case folding is often applied to subtrees and not on an entire
filesystem.

Disallowing layers from filesystems that support case folding is over
limiting.

Replace the rule that case-folding capable are not allowed as layers
with a rule that case folded directories are not allowed in a merged
directory stack.

Should case folding be enabled on an underlying directory while
overlayfs is mounted the outcome is generally undefined.

Specifically in ovl_lookup(), we check the base underlying directory
and fail with -ESTALE and write a warning to kmsg if an underlying
directory case folding is enabled.

Suggested-by: Kent Overstreet <kent.overstreet@linux.dev>
Link: https://lore.kernel.org/linux-fsdevel/20250520051600.1903319-1-kent.overstreet@linux.dev/
Signed-off-by: Amir Goldstein <amir73il@gmail.com>
Link: https://lore.kernel.org/20250602171702.1941891-1-amir73il@gmail.com
Reviewed-by: Kent Overstreet <kent.overstreet@linux.dev>
Signed-off-by: Christian Brauner <brauner@kernel.org>
2025-07-18 11:09:33 +02:00
Christian Brauner
ca115d7e75
tree-wide: s/struct fileattr/struct file_kattr/g
Now that we expose struct file_attr as our uapi struct rename all the
internal struct to struct file_kattr to clearly communicate that it is a
kernel internal struct. This is similar to struct mount_{k}attr and
others.

Link: https://lore.kernel.org/20250703-restlaufzeit-baurecht-9ed44552b481@brauner
Signed-off-by: Christian Brauner <brauner@kernel.org>
2025-07-04 16:14:39 +02:00
NeilBrown
bc9241367a
VFS: change old_dir and new_dir in struct renamedata to dentrys
all users of 'struct renamedata' have the dentry for the old and new
directories, and often have no use for the inode except to store it in
the renamedata.

This patch changes struct renamedata to hold the dentry, rather than
the inode, for the old and new directories, and changes callers to
match.  The names are also changed from a _dir suffix to _parent.  This
is consistent with other usage in namei.c and elsewhere.

This results in the removal of several local variables and several
dereferences of ->d_inode at the cost of adding ->d_inode dereferences
to vfs_rename().

Acked-by: Miklos Szeredi <miklos@szeredi.hu>
Reviewed-by: Chuck Lever <chuck.lever@oracle.com>
Reviewed-by: Namjae Jeon <linkinjeon@kernel.org>
Signed-off-by: NeilBrown <neil@brown.name>
Link: https://lore.kernel.org/174977089072.608730.4244531834577097454@noble.neil.brown.name
Signed-off-by: Christian Brauner <brauner@kernel.org>
2025-06-16 16:30:45 +02:00
Thorsten Blum
7314166ee7 ovl: Replace offsetof() with struct_size() in ovl_stack_free()
Compared to offsetof(), struct_size() provides additional compile-time
checks for structs with flexible arrays (e.g., __must_be_array()).

No functional changes intended.

Signed-off-by: Thorsten Blum <thorsten.blum@linux.dev>
Signed-off-by: Miklos Szeredi <mszeredi@redhat.com>
2025-05-05 12:47:57 +02:00
Kees Cook
8a39f1c870 ovl: Check for NULL d_inode() in ovl_dentry_upper()
In ovl_path_type() and ovl_is_metacopy_dentry() GCC notices that it is
possible for OVL_E() to return NULL (which implies that d_inode(dentry)
may be NULL). This would result in out of bounds reads via container_of(),
seen with GCC 15's -Warray-bounds -fdiagnostics-details. For example:

In file included from arch/x86/include/generated/asm/rwonce.h:1,
                 from include/linux/compiler.h:339,
                 from include/linux/export.h:5,
                 from include/linux/linkage.h:7,
                 from include/linux/fs.h:5,
                 from fs/overlayfs/util.c:7:
In function 'ovl_upperdentry_dereference',
    inlined from 'ovl_dentry_upper' at ../fs/overlayfs/util.c:305:9,
    inlined from 'ovl_path_type' at ../fs/overlayfs/util.c:216:6:
include/asm-generic/rwonce.h:44:26: error: array subscript 0 is outside array bounds of 'struct inode[7486503276667837]' [-Werror=array-bounds=]
   44 | #define __READ_ONCE(x)  (*(const volatile __unqual_scalar_typeof(x) *)&(x))
      |                         ~^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
include/asm-generic/rwonce.h:50:9: note: in expansion of macro '__READ_ONCE'
   50 |         __READ_ONCE(x);                                                 \
      |         ^~~~~~~~~~~
fs/overlayfs/ovl_entry.h:195:16: note: in expansion of macro 'READ_ONCE'
  195 |         return READ_ONCE(oi->__upperdentry);
      |                ^~~~~~~~~
  'ovl_path_type': event 1
  185 |         return inode ? OVL_I(inode)->oe : NULL;
  'ovl_path_type': event 2

Avoid this by allowing ovl_dentry_upper() to return NULL if d_inode() is
NULL, as that means the problematic dereferencing can never be reached.
Note that this fixes the over-eager compiler warning in an effort to
being able to enable -Warray-bounds globally. There is no known
behavioral bug here.

Suggested-by: Amir Goldstein <amir73il@gmail.com>
Signed-off-by: Kees Cook <kees@kernel.org>
Signed-off-by: Miklos Szeredi <mszeredi@redhat.com>
2025-04-30 15:56:11 +02:00
Christian Brauner
51c0bcf097
tree-wide: s/revert_creds_light()/revert_creds()/g
Rename all calls to revert_creds_light() back to revert_creds().

Link: https://lore.kernel.org/r/20241125-work-cred-v2-6-68b9d38bb5b2@kernel.org
Reviewed-by: Jeff Layton <jlayton@kernel.org>
Reviewed-by: Jens Axboe <axboe@kernel.dk>
Signed-off-by: Christian Brauner <brauner@kernel.org>
2024-12-02 11:25:09 +01:00
Christian Brauner
6771e004b4
tree-wide: s/override_creds_light()/override_creds()/g
Rename all calls to override_creds_light() back to overrid_creds().

Link: https://lore.kernel.org/r/20241125-work-cred-v2-5-68b9d38bb5b2@kernel.org
Reviewed-by: Jeff Layton <jlayton@kernel.org>
Reviewed-by: Jens Axboe <axboe@kernel.dk>
Signed-off-by: Christian Brauner <brauner@kernel.org>
2024-12-02 11:25:09 +01:00
Vasiliy Kovalev
c8b359dddb ovl: Filter invalid inodes with missing lookup function
Add a check to the ovl_dentry_weird() function to prevent the
processing of directory inodes that lack the lookup function.
This is important because such inodes can cause errors in overlayfs
when passed to the lowerstack.

Reported-by: syzbot+a8c9d476508bd14a90e5@syzkaller.appspotmail.com
Link: https://syzkaller.appspot.com/bug?extid=a8c9d476508bd14a90e5
Suggested-by: Miklos Szeredi <miklos@szeredi.hu>
Link: https://lore.kernel.org/linux-unionfs/CAJfpegvx-oS9XGuwpJx=Xe28_jzWx5eRo1y900_ZzWY+=gGzUg@mail.gmail.com/
Signed-off-by: Vasiliy Kovalev <kovalev@altlinux.org>
Cc: <stable@vger.kernel.org>
Signed-off-by: Amir Goldstein <amir73il@gmail.com>
2024-11-20 10:23:04 +01:00
Vinicius Costa Gomes
c5b28fc161 ovl: Optimize override/revert creds
Use override_creds_light() in ovl_override_creds() and
revert_creds_light() in ovl_revert_creds().

The _light() functions do not change the 'usage' of the credentials in
question, as they refer to the credentials associated with the
mounter, which have a longer lifetime.

In ovl_setup_cred_for_create(), do not need to modify the mounter
credentials (returned by override_creds_light()) 'usage' counter.
Add a warning to verify that we are indeed working with the mounter
credentials (stored in the superblock). Failure in this assumption
means that creds may leak.

Suggested-by: Christian Brauner <brauner@kernel.org>
Signed-off-by: Vinicius Costa Gomes <vinicius.gomes@intel.com>
Signed-off-by: Amir Goldstein <amir73il@gmail.com>
2024-11-15 08:55:39 +01:00
Vinicius Costa Gomes
fc5a1d2287 ovl: use wrapper ovl_revert_creds()
Introduce ovl_revert_creds() wrapper of revert_creds() to
match callers of ovl_override_creds().

Suggested-by: Amir Goldstein <amir73il@gmail.com>
Signed-off-by: Vinicius Costa Gomes <vinicius.gomes@intel.com>
Signed-off-by: Amir Goldstein <amir73il@gmail.com>
2024-11-11 10:45:04 +01:00
Al Viro
af58dc1f50 kernel_file_open(): get rid of inode argument
always equal to ->dentry->d_inode of the path argument these
days.

Reviewed-by: Christian Brauner <brauner@kernel.org>
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2024-04-15 16:03:24 -04:00
Linus Torvalds
0f1a876682 vfs-6.9.uuid
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Merge tag 'vfs-6.9.uuid' of git://git.kernel.org/pub/scm/linux/kernel/git/vfs/vfs

Pull vfs uuid updates from Christian Brauner:
 "This adds two new ioctl()s for getting the filesystem uuid and
  retrieving the sysfs path based on the path of a mounted filesystem.
  Getting the filesystem uuid has been implemented in filesystem
  specific code for a while it's now lifted as a generic ioctl"

* tag 'vfs-6.9.uuid' of git://git.kernel.org/pub/scm/linux/kernel/git/vfs/vfs:
  xfs: add support for FS_IOC_GETFSSYSFSPATH
  fs: add FS_IOC_GETFSSYSFSPATH
  fat: Hook up sb->s_uuid
  fs: FS_IOC_GETUUID
  ovl: convert to super_set_uuid()
  fs: super_set_uuid()
2024-03-11 11:02:06 -07:00
Kent Overstreet
dd9019604c
ovl: convert to super_set_uuid()
We don't want to be settingc sb->s_uuid directly anymore, as there's a
length field that also has to be set, and this conversion was not
completely trivial.

Acked-by: Amir Goldstein <amir73il@gmail.com>
Signed-off-by: Kent Overstreet <kent.overstreet@linux.dev>
Link: https://lore.kernel.org/r/20240207025624.1019754-3-kent.overstreet@linux.dev
Cc: Miklos Szeredi <miklos@szeredi.hu>
Cc: linux-unionfs@vger.kernel.org
Signed-off-by: Christian Brauner <brauner@kernel.org>
2024-02-08 21:20:11 +01:00
Amir Goldstein
420332b941 ovl: mark xwhiteouts directory with overlay.opaque='x'
An opaque directory cannot have xwhiteouts, so instead of marking an
xwhiteouts directory with a new xattr, overload overlay.opaque xattr
for marking both opaque dir ('y') and xwhiteouts dir ('x').

This is more efficient as the overlay.opaque xattr is checked during
lookup of directory anyway.

This also prevents unnecessary checking the xattr when reading a
directory without xwhiteouts, i.e. most of the time.

Note that the xwhiteouts marker is not checked on the upper layer and
on the last layer in lowerstack, where xwhiteouts are not expected.

Fixes: bc8df7a3dc ("ovl: Add an alternative type of whiteout")
Cc: <stable@vger.kernel.org> # v6.7
Reviewed-by: Alexander Larsson <alexl@redhat.com>
Tested-by: Alexander Larsson <alexl@redhat.com>
Signed-off-by: Amir Goldstein <amir73il@gmail.com>
2024-01-23 12:39:48 +02:00
Linus Torvalds
bf4e7080ae fix directory locking scheme on rename
broken in 6.5; we really can't lock two unrelated directories
 without holding ->s_vfs_rename_mutex first and in case of
 same-parent rename of a subdirectory 6.5 ends up doing just
 that.
 
 Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
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Merge tag 'pull-rename' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs

Pull rename updates from Al Viro:
 "Fix directory locking scheme on rename

  This was broken in 6.5; we really can't lock two unrelated directories
  without holding ->s_vfs_rename_mutex first and in case of same-parent
  rename of a subdirectory 6.5 ends up doing just that"

* tag 'pull-rename' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs:
  rename(): avoid a deadlock in the case of parents having no common ancestor
  kill lock_two_inodes()
  rename(): fix the locking of subdirectories
  f2fs: Avoid reading renamed directory if parent does not change
  ext4: don't access the source subdirectory content on same-directory rename
  ext2: Avoid reading renamed directory if parent does not change
  udf_rename(): only access the child content on cross-directory rename
  ocfs2: Avoid touching renamed directory if parent does not change
  reiserfs: Avoid touching renamed directory if parent does not change
2024-01-11 20:00:22 -08:00
Al Viro
a8b0026847 rename(): avoid a deadlock in the case of parents having no common ancestor
... and fix the directory locking documentation and proof of correctness.
Holding ->s_vfs_rename_mutex *almost* prevents ->d_parent changes; the
case where we really don't want it is splicing the root of disconnected
tree to somewhere.

In other words, ->s_vfs_rename_mutex is sufficient to stabilize "X is an
ancestor of Y" only if X and Y are already in the same tree.  Otherwise
it can go from false to true, and one can construct a deadlock on that.

Make lock_two_directories() report an error in such case and update the
callers of lock_rename()/lock_rename_child() to handle such errors.

And yes, such conditions are not impossible to create ;-/

Reviewed-by: Jan Kara <jack@suse.cz>
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2023-11-25 02:54:14 -05:00
Amir Goldstein
02d70090e0 ovl: remove redundant ofs->indexdir member
When the index feature is disabled, ofs->indexdir is NULL.
When the index feature is enabled, ofs->indexdir has the same value as
ofs->workdir and takes an extra reference.

This makes the code harder to understand when it is not always clear
that ofs->indexdir in one function is the same dentry as ofs->workdir
in another function.

Remove this redundancy, by referencing ofs->workdir directly in index
helpers and by using the ovl_indexdir() accessor in generic code.

Signed-off-by: Amir Goldstein <amir73il@gmail.com>
2023-11-20 09:49:09 +02:00
Amir Goldstein
b28060db71 ovl: fix misformatted comment
Remove misleading /** prefix from a regular comment.

Reported-by: kernel test robot <lkp@intel.com>
Closes: https://lore.kernel.org/oe-kbuild-all/202311121628.byHp8tkv-lkp@intel.com/
Signed-off-by: Amir Goldstein <amir73il@gmail.com>
2023-11-14 08:09:36 +02:00
Linus Torvalds
13d88ac54d vfs-6.7.fsid
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Merge tag 'vfs-6.7.fsid' of git://git.kernel.org/pub/scm/linux/kernel/git/vfs/vfs

Pull vfs fanotify fsid updates from Christian Brauner:
 "This work is part of the plan to enable fanotify to serve as a drop-in
  replacement for inotify. While inotify is availabe on all filesystems,
  fanotify currently isn't.

  In order to support fanotify on all filesystems two things are needed:

   (1) all filesystems need to support AT_HANDLE_FID

   (2) all filesystems need to report a non-zero f_fsid

  This contains (1) and allows filesystems to encode non-decodable file
  handlers for fanotify without implementing any exportfs operations by
  encoding a file id of type FILEID_INO64_GEN from i_ino and
  i_generation.

  Filesystems that want to opt out of encoding non-decodable file ids
  for fanotify that don't support NFS export can do so by providing an
  empty export_operations struct.

  This also partially addresses (2) by generating f_fsid for simple
  filesystems as well as freevxfs. Remaining filesystems will be dealt
  with by separate patches.

  Finally, this contains the patch from the current exportfs maintainers
  which moves exportfs under vfs with Chuck, Jeff, and Amir as
  maintainers and vfs.git as tree"

* tag 'vfs-6.7.fsid' of git://git.kernel.org/pub/scm/linux/kernel/git/vfs/vfs:
  MAINTAINERS: create an entry for exportfs
  fs: fix build error with CONFIG_EXPORTFS=m or not defined
  freevxfs: derive f_fsid from bdev->bd_dev
  fs: report f_fsid from s_dev for "simple" filesystems
  exportfs: support encoding non-decodeable file handles by default
  exportfs: define FILEID_INO64_GEN* file handle types
  exportfs: make ->encode_fh() a mandatory method for NFS export
  exportfs: add helpers to check if filesystem can encode/decode file handles
2023-11-07 12:11:26 -08:00
Alexander Larsson
bc8df7a3dc ovl: Add an alternative type of whiteout
An xattr whiteout (called "xwhiteout" in the code) is a reguar file of
zero size with the "overlay.whiteout" xattr set. A file like this in a
directory with the "overlay.whiteouts" xattrs set will be treated the
same way as a regular whiteout.

The "overlay.whiteouts" directory xattr is used in order to
efficiently handle overlay checks in readdir(), as we only need to
checks xattrs in affected directories.

The advantage of this kind of whiteout is that they can be escaped
using the standard overlay xattr escaping mechanism. So, a file with a
"overlay.overlay.whiteout" xattr would be unescaped to
"overlay.whiteout", which could then be consumed by another overlayfs
as a whiteout.

Overlayfs itself doesn't create whiteouts like this, but a userspace
mechanism could use this alternative mechanism to convert images that
may contain whiteouts to be used with overlayfs.

To work as a whiteout for both regular overlayfs mounts as well as
userxattr mounts both the "user.overlay.whiteout*" and the
"trusted.overlay.whiteout*" xattrs will need to be created.

Signed-off-by: Alexander Larsson <alexl@redhat.com>
Reviewed-by: Amir Goldstein <amir73il@gmail.com>
Signed-off-by: Amir Goldstein <amir73il@gmail.com>
2023-10-31 00:12:59 +02:00