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Diffstat (limited to 'fs/xfs/xfs_xattr.c')
-rw-r--r--fs/xfs/xfs_xattr.c19
1 files changed, 18 insertions, 1 deletions
diff --git a/fs/xfs/xfs_xattr.c b/fs/xfs/xfs_xattr.c
index ab3d22f662f2..eaf849260bd6 100644
--- a/fs/xfs/xfs_xattr.c
+++ b/fs/xfs/xfs_xattr.c
@@ -110,7 +110,24 @@ xfs_attr_change(
args->whichfork = XFS_ATTR_FORK;
xfs_attr_sethash(args);
- return xfs_attr_set(args, op, args->attr_filter & XFS_ATTR_ROOT);
+ /*
+ * Some xattrs must be resistant to allocation failure at ENOSPC, e.g.
+ * creating an inode with ACLs or security attributes requires the
+ * allocation of the xattr holding that information to succeed. Hence
+ * we allow xattrs in the VFS TRUSTED, SYSTEM, POSIX_ACL and SECURITY
+ * (LSM xattr) namespaces to dip into the reserve block pool to allow
+ * manipulation of these xattrs when at ENOSPC. These VFS xattr
+ * namespaces translate to the XFS_ATTR_ROOT and XFS_ATTR_SECURE on-disk
+ * namespaces.
+ *
+ * For most of these cases, these special xattrs will fit in the inode
+ * itself and so consume no extra space or only require temporary extra
+ * space while an overwrite is being made. Hence the use of the reserved
+ * pool is largely to avoid the worst case reservation from preventing
+ * the xattr from being created at ENOSPC.
+ */
+ return xfs_attr_set(args, op,
+ args->attr_filter & (XFS_ATTR_ROOT | XFS_ATTR_SECURE));
}