kernel.git/fs/exfat/super.c, branch linux-rolling-lts

exfat: fix remount failure in different process environments

2026-01-02T11:57:01Z

[ Upstream commit 51fc7b4ce10ccab8ea5e4876bcdc42cf5202a0ef ] The kernel test robot reported that the exFAT remount operation failed. The reason for the failure was that the process's umask is different between mount and remount, causing fs_fmask and fs_dmask are changed. Potentially, both gid and uid may also be changed. Therefore, when initializing fs_context for remount, inherit these mount options from the options used during mount. Reported-by: kernel test robot Closes: https://lore.kernel.org/oe-lkp/202511251637.81670f5c-lkp@intel.com Signed-off-by: Yuezhang Mo Signed-off-by: Namjae Jeon Signed-off-by: Sasha Levin

exfat: check return value of sb_min_blocksize in exfat_read_boot_sector

2025-11-05T13:00:16Z

sb_min_blocksize() may return 0. Check its return value to avoid accessing the filesystem super block when sb->s_blocksize is 0. Cc: stable@vger.kernel.org # v6.15 Fixes: 719c1e1829166d ("exfat: add super block operations") Reviewed-by: Christoph Hellwig Signed-off-by: Yongpeng Yang Link: https://patch.msgid.link/20251104125009.2111925-3-yangyongpeng.storage@gmail.com Signed-off-by: Christian Brauner

exfat: combine iocharset and utf8 option setup

2025-09-30T04:41:22Z

Currently, exfat utf8 mount option depends on the iocharset option value. After exfat remount, utf8 option may become inconsistent with iocharset option. If the options are inconsistent; (specifically, iocharset=utf8 but utf8=0) readdir may reference uninitalized NLS, leading to a null pointer dereference. Extract and combine utf8/iocharset setup logic into exfat_set_iocharset(). Then Replace iocharset setup logic to exfat_set_iocharset to prevent utf8/iocharset option inconsistentcy after remount. Reported-by: syzbot+3e9cb93e3c5f90d28e19@syzkaller.appspotmail.com Closes: https://syzkaller.appspot.com/bug?extid=3e9cb93e3c5f90d28e19 Signed-off-by: Sang-Heon Jeon Fixes: acab02ffcd6b ("exfat: support modifying mount options via remount") Tested-by: syzbot+3e9cb93e3c5f90d28e19@syzkaller.appspotmail.com Reviewed-by: Yuezhang Mo Signed-off-by: Namjae Jeon

exfat: support modifying mount options via remount

2025-09-30T04:34:43Z

Before this commit, all exfat-defined mount options could not be modified dynamically via remount, and no error was returned. After this commit, these three exfat-defined mount options (discard, zero_size_dir, and errors) can be modified dynamically via remount. While other exfat-defined mount options cannot be modified dynamically via remount because their old settings are cached in inodes or dentries, modifying them will be rejected with an error. Signed-off-by: Yuezhang Mo Signed-off-by: Namjae Jeon

exfat: add cluster chain loop check for dir

2025-07-31T23:34:23Z

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 Signed-off-by: Namjae Jeon

new helper: set_default_d_op()

2025-06-11T02:21:16Z

... to be used instead of manually assigning to ->s_d_op. All in-tree filesystem converted (and field itself is renamed, so any out-of-tree ones in need of conversion will be caught by compiler). Reviewed-by: Christian Brauner Signed-off-by: Al Viro

exfat: do not clear volume dirty flag during sync

2025-05-26T11:25:23Z

xfstests generic/482 tests the file system consistency after each FUA operation. It fails when run on exfat. exFAT clears the volume dirty flag with a FUA operation during sync. Since s_lock is not held when data is being written to a file, sync can be executed at the same time. When data is being written to a file, the FAT chain is updated first, and then the file size is updated. If sync is executed between updating them, the length of the FAT chain may be inconsistent with the file size. To avoid the situation where the file system is inconsistent but the volume dirty flag is cleared, this commit moves the clearing of the volume dirty flag from exfat_fs_sync() to exfat_put_super(), so that the volume dirty flag is not cleared until unmounting. After the move, there is no additional action during sync, so exfat_fs_sync() can be deleted. Reviewed-by: Sungjong Seo Signed-off-by: Yuezhang Mo Signed-off-by: Namjae Jeon

exfat: remove count used cluster from exfat_statfs()

2025-03-27T12:18:02Z

The callback function statfs() is called only after the file system is mounted. During the process of mounting the exFAT file system, the number of used clusters has been counted, so the condition "sbi->used_clusters == EXFAT_CLUSTERS_UNTRACKED" is always false and should be deleted. Signed-off-by: Yuezhang Mo Signed-off-by: Namjae Jeon

exfat: Implement sops->shutdown and ioctl

2024-09-17T22:40:56Z

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 Signed-off-by: Zhiguo Niu Signed-off-by: Namjae Jeon

exfat: do not fallback to buffered write

2024-09-17T06:09:50Z

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 Signed-off-by: Namjae Jeon