6.6-stable review patch. If anyone has any objections, please let me know.
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From: wangzijie wangzijie1@honor.com
[ Upstream commit 8175c864391753b210f3dcfae1aeed686a226ebb ]
Script to reproduce: f2fs_io write 1 0 1881 rand dsync testfile f2fs_io fallocate 0 7708672 4096 testfile f2fs_io write 1 1881 1 rand buffered testfile fsync testfile umount mount f2fs_io precache_extents testfile
When the data layout is something like this: dnode1: dnode2: [0] A [0] NEW_ADDR [1] A+1 [1] 0x0 ... [1016] A+1016 [1017] B (B!=A+1017) [1017] 0x0
During precache_extents, we map the last block(valid blkaddr) in dnode1: map->m_flags |= F2FS_MAP_MAPPED; map->m_pblk = blkaddr(valid blkaddr); map->m_len = 1; then we goto next_dnode, meet the first block in dnode2(hole), goto sync_out: map->m_flags & F2FS_MAP_MAPPED == true, and we make zero-sized extent:
map->m_len = 1 ofs = start_pgofs - map->m_lblk = 1882 - 1881 = 1 ei.fofs = start_pgofs = 1882 ei.len = map->m_len - ofs = 1 - 1 = 0
Rebased on patch[1], this patch can cover these cases to avoid zero-sized extent: A,B,C is valid blkaddr case1: dnode1: dnode2: [0] A [0] NEW_ADDR [1] A+1 [1] 0x0 ... .... [1016] A+1016 [1017] B (B!=A+1017) [1017] 0x0
case2: dnode1: dnode2: [0] A [0] C (C!=B+1) [1] A+1 [1] C+1 ... .... [1016] A+1016 [1017] B (B!=A+1017) [1017] 0x0
case3: dnode1: dnode2: [0] A [0] C (C!=B+2) [1] A+1 [1] C+1 ... .... [1015] A+1015 [1016] B (B!=A+1016) [1017] B+1 [1017] 0x0
[1] https://lore.kernel.org/linux-f2fs-devel/20250912081250.44383-1-chao@kernel....
Fixes: c4020b2da4c9 ("f2fs: support F2FS_IOC_PRECACHE_EXTENTS") Signed-off-by: wangzijie wangzijie1@honor.com Reviewed-by: Chao Yu chao@kernel.org Signed-off-by: Jaegeuk Kim jaegeuk@kernel.org Signed-off-by: Sasha Levin sashal@kernel.org --- fs/f2fs/data.c | 7 ++++--- 1 file changed, 4 insertions(+), 3 deletions(-)
diff --git a/fs/f2fs/data.c b/fs/f2fs/data.c index 0e119218ebf74..fe23ebfc88ea1 100644 --- a/fs/f2fs/data.c +++ b/fs/f2fs/data.c @@ -1751,9 +1751,10 @@ int f2fs_map_blocks(struct inode *inode, struct f2fs_map_blocks *map, int flag) if (map->m_flags & F2FS_MAP_MAPPED) { unsigned int ofs = start_pgofs - map->m_lblk;
- f2fs_update_read_extent_cache_range(&dn, - start_pgofs, map->m_pblk + ofs, - map->m_len - ofs); + if (map->m_len > ofs) + f2fs_update_read_extent_cache_range(&dn, + start_pgofs, map->m_pblk + ofs, + map->m_len - ofs); } if (map->m_next_extent) *map->m_next_extent = is_hole ? pgofs + 1 : pgofs;