Re: [PATCH] Btrfs: check items for correctness as we search V3
From: Andrey Kuzmin <hidden>
Date: 2011-03-17 19:12:32
On Thu, Mar 17, 2011 at 9:18 PM, Josef Bacik [off-list ref] wrote:
Currently if we have corrupted items things will blow up in spectacul=
ar ways.
So as we read in blocks and they are leaves, check the entire leaf to=
make sure
all of the items are correct and point to valid parts in the leaf for=
the item
data the are responsible for. =C2=A0If the item is corrupt we will ki=
ck back EIO and
not read any of the copies since they are likely to not be correct ei=
ther. =C2=A0This
will catch generic corruptions, it will be up to the individual calle=
rs of
quoted hunk ↗ jump to hunk
btrfs_search_slot to make sure their items are right. =C2=A0Thanks,diff --git a/fs/btrfs/disk-io.c b/fs/btrfs/disk-io.c index 495b1ac..9f31e11 100644 --- a/fs/btrfs/disk-io.c +++ b/fs/btrfs/disk-io.c@@ -323,6 +323,7 @@ static int btree_read_extent_buffer_pages(struct =
btrfs_root *root,
=C2=A0 =C2=A0 =C2=A0 =C2=A0int num_copies =3D 0; =C2=A0 =C2=A0 =C2=A0 =C2=A0int mirror_num =3D 0; + =C2=A0 =C2=A0 =C2=A0 clear_bit(EXTENT_BUFFER_CORRUPT, &eb->bflags); =C2=A0 =C2=A0 =C2=A0 =C2=A0io_tree =3D &BTRFS_I(root->fs_info->btree_=
inode)->io_tree;
=C2=A0 =C2=A0 =C2=A0 =C2=A0while (1) {
=C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0ret =3D read_e=xtent_buffer_pages(io_tree, eb, start, 1,
quoted hunk ↗ jump to hunk
@@ -331,6 +332,14 @@ static int btree_read_extent_buffer_pages(struct=
btrfs_root *root,
=C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0=
!verify_parent_transid(io_tree, eb, parent_transid))
=C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0=
=C2=A0 =C2=A0return ret;
+ =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 /* + =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0* This buffe=
r's crc is fine, but its contents are corrupted, so
+ =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0* there is n=
o reason to read the other copies, they won't be
+ =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0* any less w=
rong.
+ =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0*/
This sounds like an overstatement to me. You may be dealing with an error pattern CRC faled to catch, so giving up reading a mirror at this point seems premature. Regards, Andrey -- 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