On 9/17/25 10:36, wangzijie wrote: > 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-c...@kernel.org/ > > Fixes: c4020b2da4c9 ("f2fs: support F2FS_IOC_PRECACHE_EXTENTS") > Signed-off-by: wangzijie <wangzij...@honor.com>
Reviewed-by: Chao Yu <c...@kernel.org> Thanks, _______________________________________________ Linux-f2fs-devel mailing list Linux-f2fs-devel@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/linux-f2fs-devel
