kernel/git/stable/linux.git/fs/exfat/dir.c, branch linux-6.2.y

exfat: fix unexpected EOF while reading dir

2023-03-10T08:29:29+00:00

commit 6cb5d1a16a51d080fbc1649a5144cbc5ca7d6f88 upstream. If the position is not aligned with the dentry size, the return value of readdir() will be NULL and errno is 0, which means the end of the directory stream is reached. If the position is aligned with dentry size, but there is no file or directory at the position, exfat_readdir() will continue to get dentry from the next dentry. So the dentry gotten by readdir() may not be at the position. After this commit, if the position is not aligned with the dentry size, round the position up to the dentry size and continue to get the dentry. Fixes: ca06197382bd ("exfat: add directory operations") Cc: stable@vger.kernel.org # v5.7+ Reported-by: Wang Yugui Signed-off-by: Yuezhang Mo Reviewed-by: Andy Wu Reviewed-by: Aoyama Wataru Reviewed-by: Sungjong Seo Signed-off-by: Namjae Jeon Signed-off-by: Greg Kroah-Hartman

exfat: fix reporting fs error when reading dir beyond EOF

2023-03-10T08:29:29+00:00

commit 706fdcac002316893434d753be8cfb549fe1d40d upstream. Since seekdir() does not check whether the position is valid, the position may exceed the size of the directory. We found that for a directory with discontinuous clusters, if the position exceeds the size of the directory and the excess size is greater than or equal to the cluster size, exfat_readdir() will return -EIO, causing a file system error and making the file system unavailable. Reproduce this bug by: seekdir(dir, dir_size + cluster_size); dirent = readdir(dir); The following log will be printed if mount with 'errors=remount-ro'. [11166.712896] exFAT-fs (sdb1): error, invalid access to FAT (entry 0xffffffff) [11166.712905] exFAT-fs (sdb1): Filesystem has been set read-only Fixes: 1e5654de0f51 ("exfat: handle wrong stream entry size in exfat_readdir()") Cc: stable@vger.kernel.org # v5.7+ Signed-off-by: Yuezhang Mo Reviewed-by: Andy Wu Reviewed-by: Aoyama Wataru Reviewed-by: Sungjong Seo Signed-off-by: Namjae Jeon Signed-off-by: Greg Kroah-Hartman

exfat: reuse exfat_find_location() to simplify exfat_get_dentry_set()

2022-12-13T11:17:16+00:00

In exfat_get_dentry_set(), part of the code is the same as exfat_find_location(), reuse exfat_find_location() to simplify exfat_get_dentry_set(). Code refinement, no functional changes. Signed-off-by: Yuezhang Mo Reviewed-by: Andy Wu Reviewed-by: Aoyama Wataru Reviewed-by: Sungjong Seo Signed-off-by: Namjae Jeon

exfat: remove unnecessary arguments from exfat_find_dir_entry()

2022-12-12T02:02:50+00:00

This commit removes argument 'num_entries' and 'type' from exfat_find_dir_entry(). Code refinement, no functional changes. Signed-off-by: Yuezhang Mo Reviewed-by: Andy Wu Reviewed-by: Aoyama Wataru Reviewed-by: Sungjong Seo Signed-off-by: Namjae Jeon

exfat: remove call ilog2() from exfat_readdir()

2022-12-12T02:02:50+00:00

There is no need to call ilog2() for the conversions between cluster and dentry in exfat_readdir(), because these conversions can be replaced with EXFAT_DEN_TO_CLU()/EXFAT_CLU_TO_DEN(). Code refinement, no functional changes. Signed-off-by: Yuezhang Mo Reviewed-by: Andy Wu Reviewed-by: Aoyama Wataru Reviewed-by: Sungjong Seo Signed-off-by: Namjae Jeon

exfat: replace magic numbers with Macros

2022-12-12T02:02:50+00:00

Code refinement, no functional changes. Signed-off-by: Yuezhang Mo Reviewed-by: Andy Wu Reviewed-by: Aoyama Wataru Reviewed-by: Sungjong Seo Signed-off-by: Namjae Jeon

exfat: rename exfat_free_dentry_set() to exfat_put_dentry_set()

2022-12-12T02:02:49+00:00

Since struct exfat_entry_set_cache is allocated from stack, no need to free, so rename exfat_free_dentry_set() to exfat_put_dentry_set(). After renaming, the new function pair is exfat_get_dentry_set()/exfat_put_dentry_set(). Signed-off-by: Yuezhang Mo Reviewed-by: Andy Wu Reviewed-by: Aoyama Wataru Reviewed-by: Sungjong Seo Signed-off-by: Namjae Jeon

exfat: move exfat_entry_set_cache from heap to stack

2022-12-12T02:02:49+00:00

The size of struct exfat_entry_set_cache is only 56 bytes on 64-bit system, and allocating from stack is more efficient than allocating from heap. Signed-off-by: Yuezhang Mo Reviewed-by: Andy Wu Reviewed-by: Aoyama Wataru Reviewed-by: Sungjong Seo Signed-off-by: Namjae Jeon

exfat: support dynamic allocate bh for exfat_entry_set_cache

2022-12-12T02:02:49+00:00

In special cases, a file or a directory may occupied more than 19 directory entries, pre-allocating 3 bh is not enough. Such as - Support vendor secondary directory entry in the future. - Since file directory entry is damaged, the SecondaryCount field is bigger than 18. So this commit supports dynamic allocation of bh. Signed-off-by: Yuezhang Mo Reviewed-by: Andy Wu Reviewed-by: Aoyama Wataru Reviewed-by: Sungjong Seo Signed-off-by: Namjae Jeon

exfat: hint the empty entry which at the end of cluster chain

2022-12-12T02:02:48+00:00

After traversing all directory entries, hint the empty directory entry no matter whether or not there are enough empty directory entries. After this commit, hint the empty directory entries like this: 1. Hint the deleted directory entries if enough; 2. Hint the deleted and unused directory entries which at the end of the cluster chain no matter whether enough or not(Add by this commit); 3. If no any empty directory entries, hint the empty directory entries in the new cluster(Add by this commit). This avoids repeated traversal of directory entries, reduces CPU usage, and improves the performance of creating files and directories(especially on low-performance CPUs). Test create 5000 files in a class 4 SD card on imx6q-sabrelite with: for ((i=0;i<5;i++)); do sync time (for ((j=1;j<=1000;j++)); do touch file$((i*1000+j)); done) done The more files, the more performance improvements. Before After Improvement 1~1000 25.360s 22.168s 14.40% 1001~2000 38.242s 28.72ss 33.15% 2001~3000 49.134s 35.037s 40.23% 3001~4000 62.042s 41.624s 49.05% 4001~5000 73.629s 46.772s 57.42% Signed-off-by: Yuezhang Mo Reviewed-by: Andy Wu Reviewed-by: Aoyama Wataru Reviewed-by: Sungjong Seo Signed-off-by: Namjae Jeon