On Thu, May 4, 2023 at 10:41 AM Wang Yugui <wangyugui@xxxxxxxxxxxx> wrote:
>
> Hi,
>
> > From: Filipe Manana <fdmanana@xxxxxxxx>
> >
> > When using the logical to ino ioctl v2, if the flag to ignore offsets of
> > file extent items (BTRFS_LOGICAL_INO_ARGS_IGNORE_OFFSET) is given, the
> > backref walking code ends up not returning references for all file offsets
> > of an inode that point to the given logical bytenr. This happens since
> > kernel 6.2, commit 6ce6ba534418 ("btrfs: use a single argument for extent
> > offset in backref walking functions"), as it mistakenly skipped the search
> > for file extent items in a leaf that point to the target extent if that
> > flag is given. Instead it should only skip the filtering done by
> > check_extent_in_eb() - that is, it should not avoid the calls to that
> > function.
> >
> > So fix this by always calling check_extent_in_eb() and have this function
> > do the filtering only if an extent offset is given and the flag to ignore
> > offsets is not set.
> > Fixes: 6ce6ba534418 ("btrfs: use a single argument for extent offset in backref walking functions")
> > Reported-by: Vladimir Panteleev <git@xxxxxxxxxxxxxxxxxxxxx>
> > Link: https://lore.kernel.org/linux-btrfs/CAHhfkvwo=nmzrJSqZ2qMfF-rZB-ab6ahHnCD_sq9h4o8v+M7QQ@xxxxxxxxxxxxxx/
> > Tested-by: Vladimir Panteleev <git@xxxxxxxxxxxxxxxxxxxxx>
> > CC: stable@xxxxxxxxxxxxxxx # 6.2+
> > Signed-off-by: Filipe Manana <fdmanana@xxxxxxxx>
>
> fstests(btrfs/299) will fail with this patch.
Yes, I noticed it later, and it is fixed in v2.
Thanks.
>
> Best Regards
> Wang Yugui (wangyugui@xxxxxxxxxxxx)
> 2023/05/04
>
> > ---
> > fs/btrfs/backref.c | 15 +++++++--------
> > 1 file changed, 7 insertions(+), 8 deletions(-)
> >
> > diff --git a/fs/btrfs/backref.c b/fs/btrfs/backref.c
> > index e54f0884802a..8e61be3fe9a8 100644
> > --- a/fs/btrfs/backref.c
> > +++ b/fs/btrfs/backref.c
> > @@ -45,7 +45,9 @@ static int check_extent_in_eb(struct btrfs_backref_walk_ctx *ctx,
> > int root_count;
> > bool cached;
> >
> > - if (!btrfs_file_extent_compression(eb, fi) &&
> > + if (!ctx->ignore_extent_item_pos &&
> > + ctx->extent_item_pos > 0 &&
> > + !btrfs_file_extent_compression(eb, fi) &&
> > !btrfs_file_extent_encryption(eb, fi) &&
> > !btrfs_file_extent_other_encoding(eb, fi)) {
> > u64 data_offset;
> > @@ -552,13 +554,10 @@ static int add_all_parents(struct btrfs_backref_walk_ctx *ctx,
> > count++;
> > else
> > goto next;
> > - if (!ctx->ignore_extent_item_pos) {
> > - ret = check_extent_in_eb(ctx, &key, eb, fi, &eie);
> > - if (ret == BTRFS_ITERATE_EXTENT_INODES_STOP ||
> > - ret < 0)
> > - break;
> > - }
> > - if (ret > 0)
> > + ret = check_extent_in_eb(ctx, &key, eb, fi, &eie);
> > + if (ret == BTRFS_ITERATE_EXTENT_INODES_STOP || ret < 0)
> > + break;
> > + else if (ret > 0)
> > goto next;
> > ret = ulist_add_merge_ptr(parents, eb->start,
> > eie, (void **)&old, GFP_NOFS);
> > --
> > 2.35.1
>
>
