From: Darrick J. Wong <djwong@xxxxxxxxxx>
Source kernel commit: ef80de940a6344da1d4f12c948a0ad4d6ff6e841
Christoph noticed that the xfs_attr_is_leaf in xfs_attr_get_ilocked can
access the incore extent tree of the attr fork, but nothing in the
xfs_attr_get path guarantees that the incore tree is actually loaded.
Most of the time it is, but seeing as xfs_attr_is_leaf ignores the
return value of xfs_iext_get_extent I guess we've been making choices
based on random stack contents and nobody's complained?
Reported-by: Christoph Hellwig <hch@xxxxxx>
Signed-off-by: Darrick J. Wong <djwong@xxxxxxxxxx>
Reviewed-by: Christoph Hellwig <hch@xxxxxx>
---
libxfs/xfs_attr.c | 17 +++++++++++++++++
1 file changed, 17 insertions(+)
diff --git a/libxfs/xfs_attr.c b/libxfs/xfs_attr.c
index 5249f9be0..8e9e23836 100644
--- a/libxfs/xfs_attr.c
+++ b/libxfs/xfs_attr.c
@@ -85,6 +85,8 @@ xfs_attr_is_leaf(
struct xfs_iext_cursor icur;
struct xfs_bmbt_irec imap;
+ ASSERT(!xfs_need_iread_extents(ifp));
+
if (ifp->if_nextents != 1 || ifp->if_format != XFS_DINODE_FMT_EXTENTS)
return false;
@@ -222,11 +224,21 @@ int
xfs_attr_get_ilocked(
struct xfs_da_args *args)
{
+ int error;
+
xfs_assert_ilocked(args->dp, XFS_ILOCK_SHARED | XFS_ILOCK_EXCL);
if (!xfs_inode_hasattr(args->dp))
return -ENOATTR;
+ /*
+ * The incore attr fork iext tree must be loaded for xfs_attr_is_leaf
+ * to work correctly.
+ */
+ error = xfs_iread_extents(args->trans, args->dp, XFS_ATTR_FORK);
+ if (error)
+ return error;
+
if (args->dp->i_af.if_format == XFS_DINODE_FMT_LOCAL)
return xfs_attr_shortform_getvalue(args);
if (xfs_attr_is_leaf(args->dp))
@@ -868,6 +880,11 @@ xfs_attr_lookup(
return -ENOATTR;
}
+ /* Prerequisite for xfs_attr_is_leaf */
+ error = xfs_iread_extents(args->trans, args->dp, XFS_ATTR_FORK);
+ if (error)
+ return error;
+
if (xfs_attr_is_leaf(dp)) {
error = xfs_attr_leaf_hasname(args, &bp);
