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>
In exfat_find_last_cluster(), the cluster chain is traversed until
the EOF cluster. If the cluster chain includes a loop due to file
system corruption, the EOF cluster cannot be traversed, resulting
in an infinite loop.
If the number of clusters indicated by the file size is inconsistent
with the cluster chain length, exfat_find_last_cluster() will return
an error, so if this inconsistency is found, the traversal can be
aborted without traversing to the EOF cluster.
Reported-by: syzbot+f7d147e6db52b1e09dba@syzkaller.appspotmail.com
Closes: https://syzkaller.appspot.com/bug?extid=f7d147e6db52b1e09dba
Tested-by: syzbot+f7d147e6db52b1e09dba@syzkaller.appspotmail.com
Fixes: 31023864e6 ("exfat: add fat entry operations")
Signed-off-by: Yuezhang Mo <Yuezhang.Mo@sony.com>
Signed-off-by: Namjae Jeon <linkinjeon@kernel.org>
If the discard mount option is enabled, the file's clusters are
discarded when the clusters are freed. Discarding clusters one by
one will significantly reduce performance. Poor performance may
cause soft lockup when lots of clusters are freed.
This commit improves performance by discarding contiguous clusters
in batches.
Measure the performance by:
# truncate -s 80G /mnt/file
# time rm /mnt/file
Without this commit:
real 4m46.183s
user 0m0.000s
sys 0m12.863s
With this commit:
real 0m1.661s
user 0m0.000s
sys 0m0.017s
Signed-off-by: Yuezhang Mo <Yuezhang.Mo@sony.com>
Signed-off-by: Namjae Jeon <linkinjeon@kernel.org>
bitmap clear loop will take long time in __exfat_free_cluster()
if data size of file/dir enty is invalid.
If cluster bit in bitmap is already clear, stop clearing bitmap go to
out of loop.
Fixes: 31023864e6 ("exfat: add fat entry operations")
Reported-by: Kun Hu <huk23@m.fudan.edu.cn>, Jiaji Qin <jjtan24@m.fudan.edu.cn>
Reviewed-by: Sungjong Seo <sj1557.seo@samsung.com>
Signed-off-by: Namjae Jeon <linkinjeon@kernel.org>
asm/unaligned.h is always an include of asm-generic/unaligned.h;
might as well move that thing to linux/unaligned.h and include
that - there's nothing arch-specific in that header.
auto-generated by the following:
for i in `git grep -l -w asm/unaligned.h`; do
sed -i -e "s/asm\/unaligned.h/linux\/unaligned.h/" $i
done
for i in `git grep -l -w asm-generic/unaligned.h`; do
sed -i -e "s/asm-generic\/unaligned.h/linux\/unaligned.h/" $i
done
git mv include/asm-generic/unaligned.h include/linux/unaligned.h
git mv tools/include/asm-generic/unaligned.h tools/include/linux/unaligned.h
sed -i -e "/unaligned.h/d" include/asm-generic/Kbuild
sed -i -e "s/__ASM_GENERIC/__LINUX/" include/linux/unaligned.h tools/include/linux/unaligned.h
In error handling 'free_cluster', before num_alloc clusters allocated,
p_chain->size will not updated and always 0, thus the newly allocated
clusters are not freed.
Signed-off-by: Yuezhang Mo <Yuezhang.Mo@sony.com>
Reviewed-by: Andy Wu <Andy.Wu@sony.com>
Reviewed-by: Sungjong Seo <sj1557.seo@samsung.com>
Signed-off-by: Namjae Jeon <linkinjeon@kernel.org>
When allocating a new cluster, exFAT first allocates from the
next cluster of the last cluster of the file. If the last cluster
of the file is the last cluster of the volume, allocate from the
first cluster. This is a normal case, but the following error log
will be printed. It makes users confused, so this commit removes
the error log.
[1960905.181545] exFAT-fs (sdb1): hint_cluster is invalid (262130)
Signed-off-by: Yuezhang Mo <Yuezhang.Mo@sony.com>
Reviewed-by: Andy Wu <Andy.Wu@sony.com>
Reviewed-by: Sungjong Seo <sj1557.seo@samsung.com>
Signed-off-by: Namjae Jeon <linkinjeon@kernel.org>
In the removed code, num_clusters is 0, nothing is done in
exfat_chain_cont_cluster(), so it is unneeded, remove it.
Signed-off-by: Yuezhang Mo <Yuezhang.Mo@sony.com>
Reviewed-by: Andy Wu <Andy.Wu@sony.com>
Reviewed-by: Sungjong Seo <sj1557.seo@samsung.com>
Signed-off-by: Namjae Jeon <linkinjeon@kernel.org>
Using int type for sector index, there will be overflow in a large
capacity partition.
For example, if storage with sector size of 512 bytes and partition
capacity is larger than 2TB, there will be overflow.
Fixes: 1b61383854 ("exfat: reduce block requests when zeroing a cluster")
Cc: stable@vger.kernel.org # v5.19+
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>
Acked-by: Sungjong Seo <sj1557.seo@samsung.com>
Signed-off-by: Namjae Jeon <linkinjeon@kernel.org>
exfat_err() adds the new line at the end of the message by itself,
hence the passed string shouldn't contain a new line. Drop the
superfluous newline letters in the error messages in a few places that
have been put mistakenly.
Reported-by: Joe Perches <joe@perches.com>
Signed-off-by: Takashi Iwai <tiwai@suse.de>
Signed-off-by: Namjae Jeon <linkinjeon@kernel.org>
Syzbot reported slab-out-of-bounds read in exfat_clear_bitmap.
This was triggered by reproducer calling truncute with size 0,
which causes the following trace:
BUG: KASAN: slab-out-of-bounds in exfat_clear_bitmap+0x147/0x490 fs/exfat/balloc.c:174
Read of size 8 at addr ffff888115aa9508 by task syz-executor251/365
Call Trace:
__dump_stack lib/dump_stack.c:77 [inline]
dump_stack_lvl+0x1e2/0x24b lib/dump_stack.c:118
print_address_description+0x81/0x3c0 mm/kasan/report.c:233
__kasan_report mm/kasan/report.c:419 [inline]
kasan_report+0x1a4/0x1f0 mm/kasan/report.c:436
__asan_report_load8_noabort+0x14/0x20 mm/kasan/report_generic.c:309
exfat_clear_bitmap+0x147/0x490 fs/exfat/balloc.c:174
exfat_free_cluster+0x25a/0x4a0 fs/exfat/fatent.c:181
__exfat_truncate+0x99e/0xe00 fs/exfat/file.c:217
exfat_truncate+0x11b/0x4f0 fs/exfat/file.c:243
exfat_setattr+0xa03/0xd40 fs/exfat/file.c:339
notify_change+0xb76/0xe10 fs/attr.c:336
do_truncate+0x1ea/0x2d0 fs/open.c:65
Move the is_valid_cluster() helper from fatent.c to a common
header to make it reusable in other *.c files. And add is_valid_cluster()
to validate if cluster number is within valid range in exfat_clear_bitmap()
and exfat_set_bitmap().
Link: https://syzkaller.appspot.com/bug?id=50381fc73821ecae743b8cf24b4c9a04776f767c
Reported-by: syzbot+a4087e40b9c13aad7892@syzkaller.appspotmail.com
Fixes: 1e49a94cf7 ("exfat: add bitmap operations")
Cc: stable@vger.kernel.org # v5.7+
Signed-off-by: Tadeusz Struk <tadeusz.struk@linaro.org>
Reviewed-by: Sungjong Seo <sj1557.seo@samsung.com>
Signed-off-by: Namjae Jeon <linkinjeon@kernel.org>
If 'dirsync' is enabled, when zeroing a cluster, submitting
sector by sector will generate many block requests, will
cause the block device to not fully perform its performance.
This commit makes the sectors in a cluster to be submitted in
once, it will reduce the number of block requests. This will
make the block device to give full play to its performance.
Test create 1000 directories on SD card with:
$ time (for ((i=0;i<1000;i++)); do mkdir dir${i}; done)
Performance has been improved by more than 73% on imx6q-sabrelite.
Cluster size Before After Improvement
64 KBytes 3m34.036s 0m56.052s 73.8%
128 KBytes 6m2.644s 1m13.354s 79.8%
256 KBytes 11m22.202s 1m39.451s 85.4%
imx6q-sabrelite:
- CPU: 792 MHz x4
- Memory: 1GB DDR3
- SD Card: SanDisk 8GB Class 4
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: Christoph Hellwig <hch@lst.de>
Acked-by: Sungjong Seo <sj1557.seo@samsung.com>
Signed-off-by: Namjae Jeon <linkinjeon@kernel.org>
Degradation of write speed caused by frequent disk access for cluster
bitmap update on every cluster allocation could be improved by
selective syncing bitmap buffer. Change to flush bitmap buffer only
for the directory related operations.
Signed-off-by: Hyeongseok Kim <hyeongseok@gmail.com>
Acked-by: Sungjong Seo <sj1557.seo@samsung.com>
Signed-off-by: Namjae Jeon <namjae.jeon@samsung.com>
s_lock which is for protecting concurrent access of file operations is
too huge for cluster bitmap protection, so introduce a new bitmap_lock
to narrow the lock range if only need to access cluster bitmap.
Signed-off-by: Hyeongseok Kim <hyeongseok@gmail.com>
Acked-by: Sungjong Seo <sj1557.seo@samsung.com>
Signed-off-by: Namjae Jeon <namjae.jeon@samsung.com>
Replace part of exfat_zeroed_cluster() with exfat_update_bhs().
And remove exfat_sync_bhs().
Signed-off-by: Tetsuhiro Kohada <kohada.t2@gmail.com>
Reviewed-by: Sungjong Seo <sj1557.seo@samsung.com>
Signed-off-by: Namjae Jeon <namjae.jeon@samsung.com>
This flag is set/reset in exfat_put_super()/exfat_sync_fs()
to avoid sync_blockdev().
- exfat_put_super():
Before calling this, the VFS has already called sync_filesystem(),
so sync is never performed here.
- exfat_sync_fs():
After calling this, the VFS calls sync_blockdev(), so, it is meaningless
to check EXFAT_SB_DIRTY or to bypass sync_blockdev() here.
Remove the EXFAT_SB_DIRTY check to ensure synchronization.
And remove the code related to the flag.
Signed-off-by: Tetsuhiro Kohada <kohada.t2@gmail.com>
Reviewed-by: Sungjong Seo <sj1557.seo@samsung.com>
Signed-off-by: Namjae Jeon <namjae.jeon@samsung.com>
There is check error in range condition that can never be entered
even with invalid input.
Replace incorrent checking code with already existing valid checker.
Signed-off-by: hyeongseok.kim <hyeongseok@gmail.com>
Acked-by: Sungjong Seo <sj1557.seo@samsung.com>
Signed-off-by: Namjae Jeon <namjae.jeon@samsung.com>
Remove the direct use of KERN_<LEVEL> in functions by creating
separate exfat_<level> macros.
Miscellanea:
o Remove several unnecessary terminating newlines in formats
o Realign arguments and fit to 80 columns where appropriate
Signed-off-by: Joe Perches <joe@perches.com>
Signed-off-by: Namjae Jeon <namjae.jeon@samsung.com>
This adds the implementation of fat entry operations for exfat.
Signed-off-by: Namjae Jeon <namjae.jeon@samsung.com>
Signed-off-by: Sungjong Seo <sj1557.seo@samsung.com>
Reviewed-by: Pali Rohár <pali.rohar@gmail.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
