| Message ID | 1479938294-3282-1-git-send-email-bo.li.liu@oracle.com (mailing list archive) |
|---|---|
| State | Accepted |
| Headers | show |
On Wed, Nov 23, 2016 at 9:58 PM, Liu Bo <bo.li.liu@oracle.com> wrote: > This can only happen with CONFIG_BTRFS_FS_CHECK_INTEGRITY=y. > > Commit 1ba98d0 ("Btrfs: detect corruption when non-root leaf has zero item") > assumes that a leaf is its root when leaf->bytenr == btrfs_root_bytenr(root), > however, we should not use btrfs_root_bytenr(root) since it's mainly got > updated during committing transaction. So the check can fail when doing > COW on this leaf while it is a root. > > This changes to use "if (leaf == btrfs_root_node(root))" instead, just like > how we check whether leaf is a root in __btrfs_cow_block(). > > Fixes: 1ba98d086fe3 (Btrfs: detect corruption when non-root leaf has zero item) > Cc: stable@vger.kernel.org # 4.8+ > Reported-by: Jeff Mahoney <jeffm@suse.com> > Signed-off-by: Liu Bo <bo.li.liu@oracle.com> Reviewed-by: Filipe Manana <fdmanana@suse.com> Thanks Bo! > --- > v2: Tag itself for stable. > > fs/btrfs/disk-io.c | 10 +++++++--- > 1 file changed, 7 insertions(+), 3 deletions(-) > > diff --git a/fs/btrfs/disk-io.c b/fs/btrfs/disk-io.c > index 9367c31..b401e6d 100644 > --- a/fs/btrfs/disk-io.c > +++ b/fs/btrfs/disk-io.c > @@ -572,13 +572,17 @@ static noinline int check_leaf(struct btrfs_root *root, > * open_ctree() some roots has not yet been set up. > */ > if (!IS_ERR_OR_NULL(check_root)) { > + struct extent_buffer *eb; > + > + eb = btrfs_root_node(check_root); > /* if leaf is the root, then it's fine */ > - if (leaf->start != > - btrfs_root_bytenr(&check_root->root_item)) { > + if (leaf != eb) { > CORRUPT("non-root leaf's nritems is 0", > - leaf, root, 0); > + leaf, check_root, 0); > + free_extent_buffer(eb); > return -EIO; > } > + free_extent_buffer(eb); > } > return 0; > } > -- > 2.5.5 > > -- > To unsubscribe from this list: send the line "unsubscribe linux-btrfs" in > the body of a message to majordomo@vger.kernel.org > More majordomo info at http://vger.kernel.org/majordomo-info.html
diff --git a/fs/btrfs/disk-io.c b/fs/btrfs/disk-io.c index 9367c31..b401e6d 100644 --- a/fs/btrfs/disk-io.c +++ b/fs/btrfs/disk-io.c @@ -572,13 +572,17 @@ static noinline int check_leaf(struct btrfs_root *root, * open_ctree() some roots has not yet been set up. */ if (!IS_ERR_OR_NULL(check_root)) { + struct extent_buffer *eb; + + eb = btrfs_root_node(check_root); /* if leaf is the root, then it's fine */ - if (leaf->start != - btrfs_root_bytenr(&check_root->root_item)) { + if (leaf != eb) { CORRUPT("non-root leaf's nritems is 0", - leaf, root, 0); + leaf, check_root, 0); + free_extent_buffer(eb); return -EIO; } + free_extent_buffer(eb); } return 0; }
This can only happen with CONFIG_BTRFS_FS_CHECK_INTEGRITY=y. Commit 1ba98d0 ("Btrfs: detect corruption when non-root leaf has zero item") assumes that a leaf is its root when leaf->bytenr == btrfs_root_bytenr(root), however, we should not use btrfs_root_bytenr(root) since it's mainly got updated during committing transaction. So the check can fail when doing COW on this leaf while it is a root. This changes to use "if (leaf == btrfs_root_node(root))" instead, just like how we check whether leaf is a root in __btrfs_cow_block(). Fixes: 1ba98d086fe3 (Btrfs: detect corruption when non-root leaf has zero item) Cc: stable@vger.kernel.org # 4.8+ Reported-by: Jeff Mahoney <jeffm@suse.com> Signed-off-by: Liu Bo <bo.li.liu@oracle.com> --- v2: Tag itself for stable. fs/btrfs/disk-io.c | 10 +++++++--- 1 file changed, 7 insertions(+), 3 deletions(-)