Commit graph

91 commits

Author SHA1 Message Date
Rochan Avlur
942296784b exfat: preserve benign secondary entries during rename and move
Commit 8258ef2800 ("exfat: handle unreconized benign secondary
entries") added cluster freeing for benign secondary entries inside
exfat_remove_entries().  However, exfat_remove_entries() is also called
from the rename and move paths (exfat_rename_file and exfat_move_file),
where the old entry set is being relocated rather than deleted.  This
causes benign secondary entries such as vendor extension entries to be
silently destroyed on rename or cross-directory move, violating the
exFAT spec requirement (section 8.2) that implementations preserve
unrecognized benign secondary entries.

Fix this by adding a free_benign parameter to exfat_remove_entries()
so callers can suppress cluster freeing during relocation, and
extending exfat_init_ext_entry() to copy trailing benign secondary
entries from the old entry set into the new one internally.  Also
clean up the error paths to delete newly allocated entries on failure.

Fixes: 8258ef2800 ("exfat: handle unreconized benign secondary entries")
Cc: stable@vger.kernel.org
Link: https://lore.kernel.org/linux-fsdevel/CAG7tbBV--waov7XVu2FHQEc6paR92dufS=em9DW5Kzsrpu3iQg@mail.gmail.com/
Signed-off-by: Rochan Avlur <rochan.avlur@gmail.com>
Reviewed-by: Yuezhang Mo <Yuezhang.Mo@sony.com>
Signed-off-by: Namjae Jeon <linkinjeon@kernel.org>
2026-06-15 20:00:53 +09:00
Namjae Jeon
286ae36887 exfat: add support for multi-cluster allocation
Currently exfat_map_cluster() allocates and returns only one cluster
at a time even when more clusters are needed. This causes multiple
FAT walks and repeated allocation calls during large sequential writes
or when using iomap for writes. This change exfat_map_cluster() and
exfat_alloc_cluster() to be able to allocate multiple contiguous
clusters.

Acked-by: Christoph Hellwig <hch@lst.de>
Acked-by: "Darrick J. Wong" <djwong@kernel.org>
Signed-off-by: Namjae Jeon <linkinjeon@kernel.org>
2026-06-15 19:55:42 +09:00
Namjae Jeon
f07db38084 exfat: replace unsafe macros with static inline functions
The current exFAT driver relies on various macros for unit conversions
between clusters, blocks, sectors, and directory entries. These macros
are structurally unsafe as they lack type enforcement and are prone to
potential integer overflows during bit-shift operations, especially
on 64-bit architectures. Replace all arithmetic macros with static inline
functions to provide strict type checking and explicit casting.

Acked-by: Christoph Hellwig <hch@lst.de>
Acked-by: "Darrick J. Wong" <djwong@kernel.org>
Signed-off-by: Namjae Jeon <linkinjeon@kernel.org>
2026-06-15 19:55:29 +09:00
Al Viro
623f0aa1ec exfat: simplify exfat_lookup()
1) d_splice_alias() handles ERR_PTR() for inode just fine
2) no need to even look for existing aliases in case of directory inodes;
   just punt to d_splice_alias(), it'll do the right thing
3) no need to bother with 'd_unhashed(alias)' case - d_find_alias()
   would've returned that only in case of a directory, and d_splice_alias()
   will handle that just fine on its own.
4) exfat_d_anon_disconn() is entirely pointless now - we only get to
   evaluating it in case dentry->d_parent == alias->d_parent and
   alias being a non-directory.  But in that case IS_ROOT(alias) can't
   possibly be true - that would've reqiured alias == alias->d_parent,
   i.e alias == dentry->d_parent and dentry->d_parent is guaranteed to
   be a directory.  So exfat_d_anon_disconn() would always return false
   when it's called, which makes && !exfat_d_anon_disconn(alias)
   a no-op.

Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
Reviewed-by: Sungjong Seo <sj1557.seo@samsung.com>
Signed-off-by: Namjae Jeon <linkinjeon@kernel.org>
2026-06-15 19:55:26 +09:00
Chuck Lever
27e0b573dd
exfat: Implement fileattr_get for case sensitivity
Report exFAT's case sensitivity behavior via the FS_XFLAG_CASEFOLD
flag. exFAT compares names through the volume's upcase table; in
practice that table folds case, and case is preserved at rest.

Acked-by: Namjae Jeon <linkinjeon@kernel.org>
Reviewed-by: Roland Mainz <roland.mainz@nrubsig.org>
Signed-off-by: Chuck Lever <chuck.lever@oracle.com>
Link: https://github.com/exfatprogs/exfatprogs/issues/313
Link: https://patch.msgid.link/20260507-case-sensitivity-v14-4-e62cc8200435@oracle.com
Signed-off-by: Christian Brauner <brauner@kernel.org>
2026-05-11 16:50:28 +02:00
Chi Zhiling
08cf4a8181 exfat: use exfat_chain_advance helper
Replace open-coded cluster chain walking logic with exfat_chain_advance()
across exfat_readdir, exfat_find_dir_entry, exfat_count_dir_entries,
exfat_search_empty_slot and exfat_check_dir_empty.

Signed-off-by: Chi Zhiling <chizhiling@kylinos.cn>
Reviewed-by: Sungjong Seo <sj1557.seo@samsung.com>
Reviewed-by: Yuezhang Mo <Yuezhang.Mo@sony.com>
Signed-off-by: Namjae Jeon <linkinjeon@kernel.org>
2026-04-03 22:41:10 +09:00
Yang Wen
73f0125800 exfat: fix passing zero to ERR_PTR() in exfat_mkdir()
Detected by Smatch.

namei.c:890 exfat_mkdir() warn:
	passing zero to 'ERR_PTR'

Signed-off-by: Yang Wen <anmuxixixi@gmail.com>
Signed-off-by: Namjae Jeon <linkinjeon@kernel.org>
2026-03-26 20:22:26 +09:00
Chi Zhiling
d1d75eaf01 exfat: fix error handling for FAT table operations
Fix three error handling issues in FAT table operations:

1. Fix exfat_update_bh() to properly return errors from sync_dirty_buffer
2. Fix exfat_end_bh() to properly return errors from exfat_update_bh()
   and exfat_mirror_bh()
3. Fix ignored return values from exfat_chain_cont_cluster() in inode.c
   and namei.c

These fixes ensure that FAT table write errors are properly propagated
to the caller instead of being silently ignored.

Signed-off-by: Chi Zhiling <chizhiling@kylinos.cn>
Signed-off-by: Namjae Jeon <linkinjeon@kernel.org>
2026-03-05 21:09:35 +09:00
Haotian Zhang
8ffe56b104 exfat: improve error code handling in exfat_find_empty_entry()
Change the type of 'ret' from unsigned int to int in
exfat_find_empty_entry(). Although the implicit type conversion
(int -> unsigned int -> int) does not cause actual bugs in
practice, using int directly is more appropriate for storing
error codes returned by exfat_alloc_cluster().

This improves code clarity and consistency with standard error
handling practices.

Signed-off-by: Haotian Zhang <vulab@iscas.ac.cn>
Reviewed-by: Sungjong Seo <sj1557.seo@samsung.com>
Signed-off-by: Namjae Jeon <linkinjeon@kernel.org>
2026-02-12 21:21:47 +09:00
Shuhao Fu
9aee8de970 exfat: fix refcount leak in exfat_find
Fix refcount leaks in `exfat_find` related to `exfat_get_dentry_set`.

Function `exfat_get_dentry_set` would increase the reference counter of
`es->bh` on success. Therefore, `exfat_put_dentry_set` must be called
after `exfat_get_dentry_set` to ensure refcount consistency. This patch
relocate two checks to avoid possible leaks.

Fixes: 82ebecdc74 ("exfat: fix improper check of dentry.stream.valid_size")
Fixes: 13940cef95 ("exfat: add a check for invalid data size")
Signed-off-by: Shuhao Fu <sfual@cse.ust.hk>
Reviewed-by: Yuezhang Mo <Yuezhang.Mo@sony.com>
Signed-off-by: Namjae Jeon <linkinjeon@kernel.org>
2025-12-03 10:00:16 +09:00
Jeongjun Park
2d8636119b exfat: fix out-of-bounds in exfat_nls_to_ucs2()
Since the len argument value passed to exfat_ioctl_set_volume_label()
from exfat_nls_to_utf16() is passed 1 too large, an out-of-bounds read
occurs when dereferencing p_cstring in exfat_nls_to_ucs2() later.

And because of the NLS_NAME_OVERLEN macro, another error occurs when
creating a file with a period at the end using utf8 and other iocharsets.

So to avoid this, you should remove the code that uses NLS_NAME_OVERLEN
macro and make the len argument value be the length of the label string,
but with a maximum length of FSLABEL_MAX - 1.

Reported-by: syzbot+98cc76a76de46b3714d4@syzkaller.appspotmail.com
Closes: https://syzkaller.appspot.com/bug?extid=98cc76a76de46b3714d4
Fixes: d01579d590 ("exfat: Add support for FS_IOC_{GET,SET}FSLABEL")
Suggested-by: Pali Rohár <pali@kernel.org>
Signed-off-by: Jeongjun Park <aha310510@gmail.com>
Signed-off-by: Namjae Jeon <linkinjeon@kernel.org>
2025-10-15 17:53:20 +09:00
Jaehun Gou
82ebecdc74 exfat: fix improper check of dentry.stream.valid_size
We found an infinite loop bug in the exFAT file system that can lead to a
Denial-of-Service (DoS) condition. When a dentry in an exFAT filesystem is
malformed, the following system calls — SYS_openat, SYS_ftruncate, and
SYS_pwrite64 — can cause the kernel to hang.

Root cause analysis shows that the size validation code in exfat_find()
does not check whether dentry.stream.valid_size is negative. As a result,
the system calls mentioned above can succeed and eventually trigger the DoS
issue.

This patch adds a check for negative dentry.stream.valid_size to prevent
this vulnerability.

Co-developed-by: Seunghun Han <kkamagui@gmail.com>
Signed-off-by: Seunghun Han <kkamagui@gmail.com>
Co-developed-by: Jihoon Kwon <jimmyxyz010315@gmail.com>
Signed-off-by: Jihoon Kwon <jimmyxyz010315@gmail.com>
Signed-off-by: Jaehun Gou <p22gone@gmail.com>
Signed-off-by: Namjae Jeon <linkinjeon@kernel.org>
2025-10-15 14:37:21 +09:00
Linus Torvalds
f0712c2038 Description for this pull request:
- Add support for FS_IOC_{GET,SET}FSLABEL ioctl.
  - Two small clean-up patches.
  - Optimizes allocation bitmap loading time on large partitions
    with small cluster sizes.
  - Allow changes for discard, zero_size_dir, and errors options
    via remount.
  - Validate that the clusters used for the allocation bitmap are
    correctly marked as in-use during mount, preventing potential
    data corruption from reallocating the bitmap's own space.
  - Uses ratelimit to avoid too many error prints on I/O error path.
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Merge tag 'exfat-for-6.18-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/linkinjeon/exfat

Pull exfat updates from Namjae Jeon:

 - Add support for FS_IOC_{GET,SET}FSLABEL ioctl

 - Two small clean-up patches

 - Optimizes allocation bitmap loading time on large partitions with
   small cluster sizes

 - Allow changes for discard, zero_size_dir, and errors options via
   remount

 - Validate that the clusters used for the allocation bitmap are
   correctly marked as in-use during mount, preventing potential data
   corruption from reallocating the bitmap's own space

 - Uses ratelimit to avoid too many error prints on I/O error path

* tag 'exfat-for-6.18-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/linkinjeon/exfat:
  exfat: Add support for FS_IOC_{GET,SET}FSLABEL
  exfat: combine iocharset and utf8 option setup
  exfat: support modifying mount options via remount
  exfat: optimize allocation bitmap loading time
  exfat: Remove unnecessary parentheses
  exfat: drop redundant conversion to bool
  exfat: validate cluster allocation bits of the allocation bitmap
  exfat: limit log print for IO error
2025-10-03 14:02:53 -07:00
Ethan Ferguson
d01579d590 exfat: Add support for FS_IOC_{GET,SET}FSLABEL
Add support for reading / writing to the exfat volume label from the
FS_IOC_GETFSLABEL and FS_IOC_SETFSLABEL ioctls

Co-developed-by: Yuezhang Mo <Yuezhang.Mo@sony.com>
Signed-off-by: Yuezhang Mo <Yuezhang.Mo@sony.com>
Signed-off-by: Ethan Ferguson <ethan.ferguson@zetier.com>
Reviewed-by: Sungjong Seo <sj1557.seo@samsung.com>
Signed-off-by: Namjae Jeon <linkinjeon@kernel.org>
2025-09-30 13:49:31 +09:00
Al Viro
2974831dd5 exfat_find(): constify qstr argument
Nothing outside of fs/dcache.c has any business modifying
dentry names; passing &dentry->d_name as an argument should
have that argument declared as a const pointer.

Acked-by: Namjae Jeon <linkinjeon@kernel.org>
Reviewed-by: Christian Brauner <brauner@kernel.org>
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2025-09-15 21:08:33 -04:00
Yuezhang Mo
99f9a97dce exfat: add cluster chain loop check for dir
An infinite loop may occur if the following conditions occur due to
file system corruption.

(1) Condition for exfat_count_dir_entries() to loop infinitely.
    - The cluster chain includes a loop.
    - There is no UNUSED entry in the cluster chain.

(2) Condition for exfat_create_upcase_table() to loop infinitely.
    - The cluster chain of the root directory includes a loop.
    - There are no UNUSED entry and up-case table entry in the cluster
      chain of the root directory.

(3) Condition for exfat_load_bitmap() to loop infinitely.
    - The cluster chain of the root directory includes a loop.
    - There are no UNUSED entry and bitmap entry in the cluster chain
      of the root directory.

(4) Condition for exfat_find_dir_entry() to loop infinitely.
    - The cluster chain includes a loop.
    - The unused directory entries were exhausted by some operation.

(5) Condition for exfat_check_dir_empty() to loop infinitely.
    - The cluster chain includes a loop.
    - The unused directory entries were exhausted by some operation.
    - All files and sub-directories under the directory are deleted.

This commit adds checks to break the above infinite loop.

Signed-off-by: Yuezhang Mo <Yuezhang.Mo@sony.com>
Signed-off-by: Namjae Jeon <linkinjeon@kernel.org>
2025-08-01 08:34:23 +09:00
Linus Torvalds
26d8e43079 vfs-6.15-rc1.async.dir
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Merge tag 'vfs-6.15-rc1.async.dir' of git://git.kernel.org/pub/scm/linux/kernel/git/vfs/vfs

Pull vfs async dir updates from Christian Brauner:
 "This contains cleanups that fell out of the work from async directory
  handling:

   - Change kern_path_locked() and user_path_locked_at() to never return
     a negative dentry. This simplifies the usability of these helpers
     in various places

   - Drop d_exact_alias() from the remaining place in NFS where it is
     still used. This also allows us to drop the d_exact_alias() helper
     completely

   - Drop an unnecessary call to fh_update() from nfsd_create_locked()

   - Change i_op->mkdir() to return a struct dentry

     Change vfs_mkdir() to return a dentry provided by the filesystems
     which is hashed and positive. This allows us to reduce the number
     of cases where the resulting dentry is not positive to very few
     cases. The code in these places becomes simpler and easier to
     understand.

   - Repack DENTRY_* and LOOKUP_* flags"

* tag 'vfs-6.15-rc1.async.dir' of git://git.kernel.org/pub/scm/linux/kernel/git/vfs/vfs:
  doc: fix inline emphasis warning
  VFS: Change vfs_mkdir() to return the dentry.
  nfs: change mkdir inode_operation to return alternate dentry if needed.
  fuse: return correct dentry for ->mkdir
  ceph: return the correct dentry on mkdir
  hostfs: store inode in dentry after mkdir if possible.
  Change inode_operations.mkdir to return struct dentry *
  nfsd: drop fh_update() from S_IFDIR branch of nfsd_create_locked()
  nfs/vfs: discard d_exact_alias()
  VFS: add common error checks to lookup_one_qstr_excl()
  VFS: change kern_path_locked() and user_path_locked_at() to never return negative dentry
  VFS: repack LOOKUP_ bit flags.
  VFS: repack DENTRY_ flags.
2025-03-24 10:47:14 -07:00
Yuezhang Mo
13940cef95 exfat: add a check for invalid data size
Add a check for invalid data size to avoid corrupted filesystem
from being further corrupted.

Signed-off-by: Yuezhang Mo <Yuezhang.Mo@sony.com>
Signed-off-by: Namjae Jeon <linkinjeon@kernel.org>
2025-03-05 21:53:20 +09:00
Yuezhang Mo
6697f819a1 exfat: fix just enough dentries but allocate a new cluster to dir
This commit fixes the condition for allocating cluster to parent
directory to avoid allocating new cluster to parent directory when
there are just enough empty directory entries at the end of the
parent directory.

Fixes: af02c72d0b ("exfat: convert exfat_find_empty_entry() to use dentry cache")
Signed-off-by: Yuezhang Mo <Yuezhang.Mo@sony.com>
Signed-off-by: Namjae Jeon <linkinjeon@kernel.org>
2025-03-05 21:53:19 +09:00
NeilBrown
88d5baf690
Change inode_operations.mkdir to return struct dentry *
Some filesystems, such as NFS, cifs, ceph, and fuse, do not have
complete control of sequencing on the actual filesystem (e.g.  on a
different server) and may find that the inode created for a mkdir
request already exists in the icache and dcache by the time the mkdir
request returns.  For example, if the filesystem is mounted twice the
directory could be visible on the other mount before it is on the
original mount, and a pair of name_to_handle_at(), open_by_handle_at()
calls could instantiate the directory inode with an IS_ROOT() dentry
before the first mkdir returns.

This means that the dentry passed to ->mkdir() may not be the one that
is associated with the inode after the ->mkdir() completes.  Some
callers need to interact with the inode after the ->mkdir completes and
they currently need to perform a lookup in the (rare) case that the
dentry is no longer hashed.

This lookup-after-mkdir requires that the directory remains locked to
avoid races.  Planned future patches to lock the dentry rather than the
directory will mean that this lookup cannot be performed atomically with
the mkdir.

To remove this barrier, this patch changes ->mkdir to return the
resulting dentry if it is different from the one passed in.
Possible returns are:
  NULL - the directory was created and no other dentry was used
  ERR_PTR() - an error occurred
  non-NULL - this other dentry was spliced in

This patch only changes file-systems to return "ERR_PTR(err)" instead of
"err" or equivalent transformations.  Subsequent patches will make
further changes to some file-systems to return a correct dentry.

Not all filesystems reliably result in a positive hashed dentry:

- NFS, cifs, hostfs will sometimes need to perform a lookup of
  the name to get inode information.  Races could result in this
  returning something different. Note that this lookup is
  non-atomic which is what we are trying to avoid.  Placing the
  lookup in filesystem code means it only happens when the filesystem
  has no other option.
- kernfs and tracefs leave the dentry negative and the ->revalidate
  operation ensures that lookup will be called to correctly populate
  the dentry.  This could be fixed but I don't think it is important
  to any of the users of vfs_mkdir() which look at the dentry.

The recommendation to use
    d_drop();d_splice_alias()
is ugly but fits with current practice.  A planned future patch will
change this.

Reviewed-by: Jeff Layton <jlayton@kernel.org>
Reviewed-by: Jan Kara <jack@suse.cz>
Signed-off-by: NeilBrown <neilb@suse.de>
Link: https://lore.kernel.org/r/20250227013949.536172-2-neilb@suse.de
Signed-off-by: Christian Brauner <brauner@kernel.org>
2025-02-27 20:00:17 +01:00
Linus Torvalds
d3d90cc289 Provide stable parent and name to ->d_revalidate() instances
Most of the filesystem methods where we care about dentry name
 and parent have their stability guaranteed by the callers;
 ->d_revalidate() is the major exception.
 
 It's easy enough for callers to supply stable values for
 expected name and expected parent of the dentry being
 validated.  That kills quite a bit of boilerplate in
 ->d_revalidate() instances, along with a bunch of races
 where they used to access ->d_name without sufficient
 precautions.
 
 Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
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Merge tag 'pull-revalidate' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs

Pull vfs d_revalidate updates from Al Viro:
 "Provide stable parent and name to ->d_revalidate() instances

  Most of the filesystem methods where we care about dentry name and
  parent have their stability guaranteed by the callers;
  ->d_revalidate() is the major exception.

  It's easy enough for callers to supply stable values for expected name
  and expected parent of the dentry being validated. That kills quite a
  bit of boilerplate in ->d_revalidate() instances, along with a bunch
  of races where they used to access ->d_name without sufficient
  precautions"

* tag 'pull-revalidate' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs:
  9p: fix ->rename_sem exclusion
  orangefs_d_revalidate(): use stable parent inode and name passed by caller
  ocfs2_dentry_revalidate(): use stable parent inode and name passed by caller
  nfs: fix ->d_revalidate() UAF on ->d_name accesses
  nfs{,4}_lookup_validate(): use stable parent inode passed by caller
  gfs2_drevalidate(): use stable parent inode and name passed by caller
  fuse_dentry_revalidate(): use stable parent inode and name passed by caller
  vfat_revalidate{,_ci}(): use stable parent inode passed by caller
  exfat_d_revalidate(): use stable parent inode passed by caller
  fscrypt_d_revalidate(): use stable parent inode passed by caller
  ceph_d_revalidate(): propagate stable name down into request encoding
  ceph_d_revalidate(): use stable parent inode passed by caller
  afs_d_revalidate(): use stable name and parent inode passed by caller
  Pass parent directory inode and expected name to ->d_revalidate()
  generic_ci_d_compare(): use shortname_storage
  ext4 fast_commit: make use of name_snapshot primitives
  dissolve external_name.u into separate members
  make take_dentry_name_snapshot() lockless
  dcache: back inline names with a struct-wrapped array of unsigned long
  make sure that DNAME_INLINE_LEN is a multiple of word size
2025-01-30 09:13:35 -08:00
Al Viro
14d02c3dcf exfat_d_revalidate(): use stable parent inode passed by caller
... no need to bother with ->d_lock and ->d_parent->d_inode.

Reviewed-by: Jeff Layton <jlayton@kernel.org>
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2025-01-27 19:25:23 -05:00
Al Viro
5be1fa8abd Pass parent directory inode and expected name to ->d_revalidate()
->d_revalidate() often needs to access dentry parent and name; that has
to be done carefully, since the locking environment varies from caller
to caller.  We are not guaranteed that dentry in question will not be
moved right under us - not unless the filesystem is such that nothing
on it ever gets renamed.

It can be dealt with, but that results in boilerplate code that isn't
even needed - the callers normally have just found the dentry via dcache
lookup and want to verify that it's in the right place; they already
have the values of ->d_parent and ->d_name stable.  There is a couple
of exceptions (overlayfs and, to less extent, ecryptfs), but for the
majority of calls that song and dance is not needed at all.

It's easier to make ecryptfs and overlayfs find and pass those values if
there's a ->d_revalidate() instance to be called, rather than doing that
in the instances.

This commit only changes the calling conventions; making use of supplied
values is left to followups.

NOTE: some instances need more than just the parent - things like CIFS
may need to build an entire path from filesystem root, so they need
more precautions than the usual boilerplate.  This series doesn't
do anything to that need - these filesystems have to keep their locking
mechanisms (rename_lock loops, use of dentry_path_raw(), private rwsem
a-la v9fs).

One thing to keep in mind when using name is that name->name will normally
point into the pathname being resolved; the filename in question occupies
name->len bytes starting at name->name, and there is NUL somewhere after it,
but it the next byte might very well be '/' rather than '\0'.  Do not
ignore name->len.

Reviewed-by: Jeff Layton <jlayton@kernel.org>
Reviewed-by: Gabriel Krisman Bertazi <gabriel@krisman.be>
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2025-01-27 19:25:23 -05:00
Yuezhang Mo
70465acbb0 exfat: fix exfat_find_empty_entry() not returning error on failure
On failure, "dentry" is the error code. If the error code indicates
that there is no space, a new cluster may need to be allocated; for
other errors, it should be returned directly.

Only on success, "dentry" is the index of the directory entry, and
it needs to be converted into the directory entry index within the
cluster where it is located.

Fixes: 8a3f5711ad ("exfat: reduce FAT chain traversal")
Reported-by: syzbot+6f6c9397e0078ef60bce@syzkaller.appspotmail.com
Tested-by: syzbot+6f6c9397e0078ef60bce@syzkaller.appspotmail.com
Signed-off-by: Yuezhang Mo <Yuezhang.Mo@sony.com>
Reviewed-by: Sungjong Seo <sj1557.seo@samsung.com>
Signed-off-by: Namjae Jeon <linkinjeon@kernel.org>
2024-12-17 20:21:59 +09:00
Yuezhang Mo
8a3f5711ad exfat: reduce FAT chain traversal
Before this commit, ->dir and ->entry of exfat_inode_info record the
first cluster of the parent directory and the directory entry index
starting from this cluster.

The directory entry set will be gotten during write-back-inode/rmdir/
unlink/rename. If the clusters of the parent directory are not
continuous, the FAT chain will be traversed from the first cluster of
the parent directory to find the cluster where ->entry is located.

After this commit, ->dir records the cluster where the first directory
entry in the directory entry set is located, and ->entry records the
directory entry index in the cluster, so that there is almost no need
to access the FAT when getting the directory entry set.

Signed-off-by: Yuezhang Mo <Yuezhang.Mo@sony.com>
Reviewed-by: Aoyama Wataru <wataru.aoyama@sony.com>
Reviewed-by: Daniel Palmer <daniel.palmer@sony.com>
Reviewed-by: Sungjong Seo <sj1557.seo@samsung.com>
Signed-off-by: Namjae Jeon <linkinjeon@kernel.org>
2024-11-25 17:08:27 +09:00
Yuezhang Mo
33a86666d3 exfat: remove argument 'p_dir' from exfat_add_entry()
The output of argument 'p_dir' of exfat_add_entry() is not used
in either exfat_mkdir() or exfat_create(), remove the argument.

Code refinement, no functional changes.

Signed-off-by: Yuezhang Mo <Yuezhang.Mo@sony.com>
Reviewed-by: Aoyama Wataru <wataru.aoyama@sony.com>
Reviewed-by: Daniel Palmer <daniel.palmer@sony.com>
Reviewed-by: Sungjong Seo <sj1557.seo@samsung.com>
Signed-off-by: Namjae Jeon <linkinjeon@kernel.org>
2024-11-25 17:08:25 +09:00
Yuezhang Mo
0891c7313d exfat: move exfat_chain_set() out of __exfat_resolve_path()
__exfat_resolve_path() mixes two functions. The first one is to
resolve and check if the path is valid. The second one is to output
the cluster assigned to the directory.

The second one is only needed when need to traverse the directory
entries, and calling exfat_chain_set() so early causes p_dir to be
passed as an argument multiple times, increasing the complexity of
the code.

This commit moves the call to exfat_chain_set() before traversing
directory entries.

Signed-off-by: Yuezhang Mo <Yuezhang.Mo@sony.com>
Reviewed-by: Aoyama Wataru <wataru.aoyama@sony.com>
Reviewed-by: Daniel Palmer <daniel.palmer@sony.com>
Reviewed-by: Sungjong Seo <sj1557.seo@samsung.com>
Signed-off-by: Namjae Jeon <linkinjeon@kernel.org>
2024-11-25 17:08:24 +09:00
Yuezhang Mo
ac844e9136 exfat: add exfat_get_dentry_set_by_ei() helper
This helper gets the directory entry set of the file for the exfat
inode which has been created.

It's used to remove all the instances of the pattern it replaces
making the code cleaner, it's also a preparation for changing ->dir
to record the cluster where the directory entry set is located and
changing ->entry to record the index of the directory entry within
the cluster.

Signed-off-by: Yuezhang Mo <Yuezhang.Mo@sony.com>
Reviewed-by: Aoyama Wataru <wataru.aoyama@sony.com>
Reviewed-by: Daniel Palmer <daniel.palmer@sony.com>
Reviewed-by: Sungjong Seo <sj1557.seo@samsung.com>
Signed-off-by: Namjae Jeon <linkinjeon@kernel.org>
2024-11-25 17:08:23 +09:00
Yuezhang Mo
06a2b0b3b4 exfat: rename argument name for exfat_move_file and exfat_rename_file
In this exfat implementation, the relationship between inode and ei
is ei=EXFAT_I(inode). However, in the arguments of exfat_move_file()
and exfat_rename_file(), argument 'inode' indicates the parent
directory, but argument 'ei' indicates the target file to be renamed.
They do not have the above relationship, which is not friendly to code
readers.

So this commit renames 'inode' to 'parent_inode', making the argument
name match its role.

Signed-off-by: Yuezhang Mo <Yuezhang.Mo@sony.com>
Reviewed-by: Sungjong Seo <sj1557.seo@samsung.com>
Signed-off-by: Namjae Jeon <linkinjeon@kernel.org>
2024-11-25 17:08:21 +09:00
Yuezhang Mo
30ef0e0d7f exfat: remove unnecessary read entry in __exfat_rename()
To determine whether it is a directory, there is no need to read its
directory entry, just use S_ISDIR(inode->i_mode).

Signed-off-by: Yuezhang Mo <Yuezhang.Mo@sony.com>
Reviewed-by: Aoyama Wataru <wataru.aoyama@sony.com>
Reviewed-by: Daniel Palmer <daniel.palmer@sony.com>
Reviewed-by: Sungjong Seo <sj1557.seo@samsung.com>
Signed-off-by: Namjae Jeon <linkinjeon@kernel.org>
2024-11-25 17:08:21 +09:00
Namjae Jeon
02dffe9ab0 exfat: fix uninit-value in __exfat_get_dentry_set
There is no check if stream size and start_clu are invalid.
If start_clu is EOF cluster and stream size is 4096, It will
cause uninit value access. because ei->hint_femp.eidx could
be 128(if cluster size is 4K) and wrong hint will allocate
next cluster. and this cluster will be same with the cluster
that is allocated by exfat_extend_valid_size(). The previous
patch will check invalid start_clu, but for clarity, initialize
hint_femp.eidx to zero.

Cc: stable@vger.kernel.org
Reported-by: syzbot+01218003be74b5e1213a@syzkaller.appspotmail.com
Tested-by: syzbot+01218003be74b5e1213a@syzkaller.appspotmail.com
Reviewed-by: Yuezhang Mo <Yuezhang.Mo@sony.com>
Signed-off-by: Namjae Jeon <linkinjeon@kernel.org>
2024-11-25 17:08:21 +09:00
Yuezhang Mo
184fa506e3 exfat: fix out-of-bounds access of directory entries
In the case of the directory size is greater than or equal to
the cluster size, if start_clu becomes an EOF cluster(an invalid
cluster) due to file system corruption, then the directory entry
where ei->hint_femp.eidx hint is outside the directory, resulting
in an out-of-bounds access, which may cause further file system
corruption.

This commit adds a check for start_clu, if it is an invalid cluster,
the file or directory will be treated as empty.

Cc: stable@vger.kernel.org
Signed-off-by: Yuezhang Mo <Yuezhang.Mo@sony.com>
Co-developed-by: Namjae Jeon <linkinjeon@kernel.org>
Signed-off-by: Namjae Jeon <linkinjeon@kernel.org>
2024-11-25 17:08:20 +09:00
Dongliang Cui
f761fcdd28 exfat: Implement sops->shutdown and ioctl
We found that when writing a large file through buffer write, if the
disk is inaccessible, exFAT does not return an error normally, which
leads to the writing process not stopping properly.

To easily reproduce this issue, you can follow the steps below:

1. format a device to exFAT and then mount (with a full disk erase)
2. dd if=/dev/zero of=/exfat_mount/test.img bs=1M count=8192
3. eject the device

You may find that the dd process does not stop immediately and may
continue for a long time.

The root cause of this issue is that during buffer write process,
exFAT does not need to access the disk to look up directory entries
or the FAT table (whereas FAT would do) every time data is written.
Instead, exFAT simply marks the buffer as dirty and returns,
delegating the writeback operation to the writeback process.

If the disk cannot be accessed at this time, the error will only be
returned to the writeback process, and the original process will not
receive the error, so it cannot be returned to the user side.

When the disk cannot be accessed normally, an error should be returned
to stop the writing process.

Implement sops->shutdown and ioctl to shut down the file system
when underlying block device is marked dead.

Signed-off-by: Dongliang Cui <dongliang.cui@unisoc.com>
Signed-off-by: Zhiguo Niu <zhiguo.niu@unisoc.com>
Signed-off-by: Namjae Jeon <linkinjeon@kernel.org>
2024-09-18 07:40:56 +09:00
Yuezhang Mo
231eb762bb exfat: do not fallback to buffered write
After commit(11a347fb6cef exfat: change to get file size from
DataLength), the remaining area or hole had been filled with
zeros before calling exfat_direct_IO(), so there is no need to
fallback to buffered write, and ->i_size_aligned is no longer
needed, drop it.

Signed-off-by: Yuezhang Mo <Yuezhang.Mo@sony.com>
Signed-off-by: Namjae Jeon <linkinjeon@kernel.org>
2024-09-17 15:09:50 +09:00
Yuezhang Mo
fba27cf005 exfat: drop ->i_size_ondisk
->i_size_ondisk is no longer used by exfat_write_begin() after
commit(11a347fb6cef exfat: change to get file size from DataLength),
drop it.

Signed-off-by: Yuezhang Mo <Yuezhang.Mo@sony.com>
Signed-off-by: Namjae Jeon <linkinjeon@kernel.org>
2024-09-17 14:46:51 +09:00
Yuezhang Mo
dc38fdc51b exfat: remove duplicate update parent dir
For renaming, the directory only needs to be updated once if it
is in the same directory.

Signed-off-by: Yuezhang Mo <Yuezhang.Mo@sony.com>
Reviewed-by: Andy Wu <Andy.Wu@sony.com>
Reviewed-by: Aoyama Wataru <wataru.aoyama@sony.com>
Reviewed-by: Sungjong Seo <sj1557.seo@samsung.com>
Signed-off-by: Namjae Jeon <linkinjeon@kernel.org>
2024-03-19 20:56:10 +09:00
Yuezhang Mo
96cf51accc exfat: do not sync parent dir if just update timestamp
When sync or dir_sync is enabled, there is no need to sync the
parent directory's inode if only for updating its timestamp.

1. If an unexpected power failure occurs, the timestamp of the
   parent directory is not updated to the storage, which has no
   impact on the user.

2. The number of writes will be greatly reduced, which can not
   only improve performance, but also prolong device life.

Signed-off-by: Yuezhang Mo <Yuezhang.Mo@sony.com>
Reviewed-by: Andy Wu <Andy.Wu@sony.com>
Reviewed-by: Aoyama Wataru <wataru.aoyama@sony.com>
Reviewed-by: Sungjong Seo <sj1557.seo@samsung.com>
Signed-off-by: Namjae Jeon <linkinjeon@kernel.org>
2024-03-19 20:56:05 +09:00
Yuezhang Mo
af02c72d0b exfat: convert exfat_find_empty_entry() to use dentry cache
Before this conversion, each dentry traversed needs to be read
from the storage device or page cache. There are at least 16
dentries in a sector. This will result in frequent page cache
searches.

After this conversion, if all directory entries in a sector are
used, the sector only needs to be read once.

Signed-off-by: Yuezhang Mo <Yuezhang.Mo@sony.com>
Reviewed-by: Andy Wu <Andy.Wu@sony.com>
Reviewed-by: Aoyama Wataru <wataru.aoyama@sony.com>
Reviewed-by: Sungjong Seo <sj1557.seo@samsung.com>
Signed-off-by: Namjae Jeon <linkinjeon@kernel.org>
2024-03-19 20:55:54 +09:00
Yuezhang Mo
d97e060673 exfat: convert exfat_init_ext_entry() to use dentry cache
Before this conversion, in exfat_init_ext_entry(), to init
the dentries in a dentry set, the sync times is equals the
dentry number if 'dirsync' or 'sync' is enabled.
That affects not only performance but also device life.

After this conversion, only needs to be synchronized once if
'dirsync' or 'sync' is enabled.

Signed-off-by: Yuezhang Mo <Yuezhang.Mo@sony.com>
Reviewed-by: Andy Wu <Andy.Wu@sony.com>
Reviewed-by: Aoyama Wataru <wataru.aoyama@sony.com>
Reviewed-by: Sungjong Seo <sj1557.seo@samsung.com>
Signed-off-by: Namjae Jeon <linkinjeon@kernel.org>
2024-03-19 20:55:49 +09:00
Yuezhang Mo
4e1aa22fea exfat: move free cluster out of exfat_init_ext_entry()
exfat_init_ext_entry() is an init function, it's a bit strange
to free cluster in it. And the argument 'inode' will be removed
from exfat_init_ext_entry(). So this commit changes to free the
cluster in exfat_remove_entries().

Code refinement, no functional changes.

Signed-off-by: Yuezhang Mo <Yuezhang.Mo@sony.com>
Reviewed-by: Andy Wu <Andy.Wu@sony.com>
Reviewed-by: Aoyama Wataru <wataru.aoyama@sony.com>
Reviewed-by: Sungjong Seo <sj1557.seo@samsung.com>
Signed-off-by: Namjae Jeon <linkinjeon@kernel.org>
2024-03-19 20:55:45 +09:00
Yuezhang Mo
ff4343da02 exfat: convert exfat_remove_entries() to use dentry cache
Before this conversion, in exfat_remove_entries(), to mark the
dentries in a dentry set as deleted, the sync times is equals
the dentry numbers if 'dirsync' or 'sync' is enabled.
That affects not only performance but also device life.

After this conversion, only needs to be synchronized once if
'dirsync' or 'sync' is enabled.

Signed-off-by: Yuezhang Mo <Yuezhang.Mo@sony.com>
Reviewed-by: Andy Wu <Andy.Wu@sony.com>
Reviewed-by: Aoyama Wataru <wataru.aoyama@sony.com>
Reviewed-by: Sungjong Seo <sj1557.seo@samsung.com>
Signed-off-by: Namjae Jeon <linkinjeon@kernel.org>
2024-03-19 20:55:40 +09:00
Yuezhang Mo
cf8663fa99 exfat: convert exfat_add_entry() to use dentry cache
After this conversion, if "dirsync" or "sync" is enabled, the
number of synchronized dentries in exfat_add_entry() will change
from 2 to 1.

Signed-off-by: Yuezhang Mo <Yuezhang.Mo@sony.com>
Reviewed-by: Andy Wu <Andy.Wu@sony.com>
Reviewed-by: Aoyama Wataru <wataru.aoyama@sony.com>
Reviewed-by: Sungjong Seo <sj1557.seo@samsung.com>
Signed-off-by: Namjae Jeon <linkinjeon@kernel.org>
2024-03-19 20:55:36 +09:00
Yuezhang Mo
11a347fb6c exfat: change to get file size from DataLength
In stream extension directory entry, the ValidDataLength
field describes how far into the data stream user data has
been written, and the DataLength field describes the file
size.

Signed-off-by: Yuezhang Mo <Yuezhang.Mo@sony.com>
Reviewed-by: Andy Wu <Andy.Wu@sony.com>
Reviewed-by: Aoyama Wataru <wataru.aoyama@sony.com>
Reviewed-by: Sungjong Seo <sj1557.seo@samsung.com>
Signed-off-by: Namjae Jeon <linkinjeon@kernel.org>
2024-01-08 21:57:22 +09:00
Yuezhang Mo
ee785c15b5 exfat: support create zero-size directory
This commit adds mount option 'zero_size_dir'. If this option
enabled, don't allocate a cluster to directory when creating
it, and set the directory size to 0.

On Windows, a cluster is allocated for a directory when it is
created, so the mount option is disabled by default.

Signed-off-by: Yuezhang Mo <Yuezhang.Mo@sony.com>
Reviewed-by: Andy Wu <Andy.Wu@sony.com>
Reviewed-by: Aoyama Wataru <wataru.aoyama@sony.com>
Signed-off-by: Namjae Jeon <linkinjeon@kernel.org>
2023-10-31 10:01:45 +09:00
Yuezhang Mo
dab48b8f2f exfat: support handle zero-size directory
After repairing a corrupted file system with exfatprogs' fsck.exfat,
zero-size directories may result. It is also possible to create
zero-size directories in other exFAT implementation, such as Paragon
ufsd dirver.

As described in the specification, the lower directory size limits
is 0 bytes.

Without this commit, sub-directories and files cannot be created
under a zero-size directory, and it cannot be removed.

Signed-off-by: Yuezhang Mo <Yuezhang.Mo@sony.com>
Reviewed-by: Andy Wu <Andy.Wu@sony.com>
Reviewed-by: Aoyama Wataru <wataru.aoyama@sony.com>
Signed-off-by: Namjae Jeon <linkinjeon@kernel.org>
2023-10-31 10:01:08 +09:00
Jan Cincera
0ab8ba7186 exfat: add ioctls for accessing attributes
Add GET and SET attributes ioctls to enable attribute modification.
We already do this in FAT and a few userspace utils made for it would
benefit from this also working on exFAT, namely fatattr.

Signed-off-by: Jan Cincera <hcincera@gmail.com>
Signed-off-by: Namjae Jeon <linkinjeon@kernel.org>
2023-10-31 10:00:51 +09:00
Jeff Layton
4c72a36edd
exfat: convert to new timestamp accessors
Convert to using the new inode timestamp accessor functions.

Signed-off-by: Jeff Layton <jlayton@kernel.org>
Link: https://lore.kernel.org/r/20231004185347.80880-31-jlayton@kernel.org
Signed-off-by: Christian Brauner <brauner@kernel.org>
2023-10-18 13:26:21 +02:00
Jeff Layton
f29f190828 exfat: convert to ctime accessor functions
In later patches, we're going to change how the inode's ctime field is
used. Switch to using accessor functions instead of raw accesses of
inode->i_ctime.

Signed-off-by: Jeff Layton <jlayton@kernel.org>
Reviewed-by: Jan Kara <jack@suse.cz>
Message-Id: <20230705190309.579783-38-jlayton@kernel.org>
Signed-off-by: Christian Brauner <brauner@kernel.org>
2023-07-13 10:28:07 +02:00
Jeff Layton
d06cdfddd1 exfat: convert to simple_rename_timestamp
A rename potentially involves updating 4 different inode timestamps.
Convert to the new simple_rename_timestamp helper function.

Signed-off-by: Jeff Layton <jlayton@kernel.org>
Message-Id: <20230705190309.579783-10-jlayton@kernel.org>
Signed-off-by: Christian Brauner <brauner@kernel.org>
2023-07-10 10:08:16 +02:00
Jeff Layton
fb91816e40 exfat: ensure that ctime is updated whenever the mtime is
When removing entries from a directory, the ctime must also be updated
alongside the mtime.

Signed-off-by: Jeff Layton <jlayton@kernel.org>
Message-Id: <20230705190309.579783-4-jlayton@kernel.org>
Signed-off-by: Christian Brauner <brauner@kernel.org>
2023-07-10 10:04:52 +02:00