diff options
| author | Zhan Xusheng <zhanxusheng1024@gmail.com> | 2026-08-18 22:55:35 +0800 |
|---|---|---|
| committer | Jaegeuk Kim <jaegeuk@kernel.org> | 2026-08-21 01:00:38 +0000 |
| commit | 0f448bb3767ef6119f5cdeabcae3f10d6e75aed6 (patch) | |
| tree | 6492fbdac40893a132fdec02fc4b63dbc67d01ee | |
| parent | 8ec06f50ddd8d201bd7e55b896ae28ed9d4cb7d1 (diff) | |
f2fs: fix i_size when pinned fallocate partially fails
From: Zhan Xusheng <zhanxusheng@xiaomi.com>
Commit 4275b59673eb ("f2fs: fix to round down start offset of fallocate
for pin file") moved the allocation loop's start down to a section
boundary, but the error path still converts @expanded against @pg_start,
which holds the unrounded start.
@pg_start exists for that conversion: commit 88f2cfc5fa90 ("f2fs: fix to
update last i_size if fallocate partially succeeds") added it as an
immutable base because map.m_lblk moves every round. Each round now maps
exactly sec_blks blocks starting from rounddown(pg_start, sec_blks), so
pg_start + expanded overshoots the last allocated block by
pg_start % sec_blks, and a partial failure leaves i_size covering a tail
that was never allocated. Nothing corrects that afterwards either, since
file_dont_truncate() has already cleared FADVISE_TRUNC_BIT.
It needs a start offset that is not section aligned plus a fallocate that
hits ENOSPC partway, so the error path runs with expanded > 0. On an
80 MiB image with 2 MiB sections:
truncate -s 80M img
mkfs.f2fs -s 1 -f img
mount -o loop img /mnt
touch /mnt/pinned
f2fs_io pinfile set /mnt/pinned
# 2093056 = block 511, so pg_start % sec_blks = 511
f2fs_io fallocate 0 2093056 536870912 /mnt/pinned
stat -c %s /mnt/pinned
filefrag -v /mnt/pinned
The last extent ends at block 10737 either way. Before, i_size is
46075904, block 11249, so 511 blocks of it were never allocated, and
filefrag does not mark the last extent eof. After, i_size is 43982848,
block 10738, and eof is back. A kernel from before that commit also
shows no overshoot.
Keep @pg_start pointing at where allocation actually begins.
Fixes: 4275b59673eb ("f2fs: fix to round down start offset of fallocate for pin file")
Cc: stable@vger.kernel.org
Signed-off-by: Zhan Xusheng <zhanxusheng@xiaomi.com>
Reviewed-by: Chao Yu <chao@kernel.org>
Signed-off-by: Jaegeuk Kim <jaegeuk@kernel.org>
| -rw-r--r-- | fs/f2fs/file.c | 5 |
1 files changed, 3 insertions, 2 deletions
diff --git a/fs/f2fs/file.c b/fs/f2fs/file.c index a54b3ab52f1a..d82be8c1502a 100644 --- a/fs/f2fs/file.c +++ b/fs/f2fs/file.c @@ -2001,8 +2001,9 @@ static int f2fs_expand_inode_data(struct inode *inode, loff_t offset, block_t sec_len; if (map.m_lblk % sec_blks) { - map.m_lblk = rounddown(map.m_lblk, sec_blks); - map.m_len = pg_end - map.m_lblk; + pg_start = rounddown(map.m_lblk, sec_blks); + map.m_lblk = pg_start; + map.m_len = pg_end - pg_start; if (off_end) map.m_len++; } |