Re: [f2fs-dev] [PATCH] f2fs: fix to avoid potential section-unaligned pinfile
Chao Yu via Linux-f2fs-devel <[email protected]>
| Newsgroups | net.sourceforge.lists.linux-f2fs-devel,org.kernel.vger.linux-kernel |
|---|---|
| Message-ID | <[email protected]> |
On 6/30/26 16:50, Zhiguo Niu wrote: > Chao Yu via Linux-f2fs-devel <[email protected]> > 于2026年6月29日周一 19:52写道： >> >> Blocks of pinfile may not aligned to section size due to wrong use >> on pinfile, result in heavy overhead of GC, let avoid this by >> adding additional check condition in f2fs_setattr(). >> >> - truncate -s 8mb pinfile >> : random checkpoint may persist filesize w/ inode >> - fallocate -o 0 -l 8mb pinfile >> - f2fs_fallocate >> - f2fs_expand_inode_data >> - f2fs_allocate_pinning_section >> - f2fs_map_blocks >> - f2fs_map_lock >> - __allocate_data_block >> - file_need_truncate >> : w/ FADVISE_TRUNC_BIT, we can expect unaligned mapping can be >> truncated while open() if f2fs is not umount abnormally >> - f2fs_map_unlock >> : following f2fs checkpoint and sudden power-cut >> >> - mount >> - open pinfile >> - f2fs_file_open >> - finish_preallocate_blocks >> - truncate_setsize >> : filesize is 8mb >> - f2fs_truncate >> : can only truncate block outside filesize, rather than truncating >> unaligned blocks inside filesize > Hi Chao, > 8MB is section alinged when fallocated by f2fs_allocate_pinning_section?? > so How could there are unaligned blocks inside filesize? Zhiguo, As partial blkaddrs were persisted and recovered, see comments around f2fs_map_unlock(). >> >> Fixes: f5a53edcf01e ("f2fs: support aligned pinned file") >> Cc: [email protected] >> Cc: Daeho Jeong <[email protected]> >> Signed-off-by: Chao Yu <[email protected]> >> --- >> fs/f2fs/file.c | 28 +++++++++++++++++----------- >> 1 file changed, 17 insertions(+), 11 deletions(-) >> >> diff --git a/fs/f2fs/file.c b/fs/f2fs/file.c >> index f4facd409d9b..11cc8d79c235 100644 >> --- a/fs/f2fs/file.c >> +++ b/fs/f2fs/file.c >> @@ -1107,17 +1107,23 @@ int f2fs_setattr(struct mnt_idmap *idmap, struct dentry *dentry, >> !IS_ALIGNED(attr->ia_size, >> F2FS_BLK_TO_BYTES(fi->i_cluster_size))) >> return -EINVAL; >> - /* >> - * To prevent scattered pin block generation, we don't allow >> - * smaller/equal size unaligned truncation for pinned file. >> - * We only support overwrite IO to pinned file, so don't >> - * care about larger size truncation. >> - */ >> - if (f2fs_is_pinned_file(inode) && >> - attr->ia_size <= i_size_read(inode) && >> - !IS_ALIGNED(attr->ia_size, >> - F2FS_BLK_TO_BYTES(CAP_BLKS_PER_SEC(sbi)))) >> - return -EINVAL; >> + >> + if (f2fs_is_pinned_file(inode)) { >> + /* >> + * It may break section-aligned fallocate recovery >> + * mechanism, so do not allow larger size truncation. >> + */ >> + if (attr->ia_size > i_size_read(inode)) >> + return -EINVAL; > Is it ok if we allow larger size truncation and also limit it to > aligned "F2FS_BLK_TO_BYTES(CAP_BLKS_PER_SEC(sbi)"? No, I think above example will still suffer section-unaligned issue. Thanks, > thanks! >> + /* >> + * To prevent scattered pin block generation, we don't >> + * allow smaller/equal size unaligned truncation for >> + * pinned file. >> + */ >> + else if (!IS_ALIGNED(attr->ia_size, >> + F2FS_BLK_TO_BYTES(CAP_BLKS_PER_SEC(sbi)))) >> + return -EINVAL; >> + } >> } >> >> if (is_quota_modification(idmap, inode, attr)) { >> -- >> 2.49.0 >> >> >> >> _______________________________________________ >> Linux-f2fs-devel mailing list >> [email protected] >> https://lists.sourceforge.net/lists/listinfo/linux-f2fs-devel _______________________________________________ Linux-f2fs-devel mailing list [email protected] https://lists.sourceforge.net/lists/listinfo/linux-f2fs-devel