[2.06 RELEASE PATCH v2 4/4] fs/xfs: Add needsrepair incompat feature support

[Javier Martinez Canillas]

The XFS now has an incompat feature flag to indicate that the filesystem
needs to be repaired. The Linux kernel refuses to mount a filesystem that
has it set and only the xfs_repair tool is able to clear that flag.

The GRUB doesn't have the concept of mounting filesystems and just attempt
to read the files. But it does some sanity checking before attempting to
read from a filesystem.

Among the things which are tested, is if the super block only has set the
incompatible features flags that are supported by GRUB. If it contains any
flags that are not listed as supported, reading the XFS filesystem fails.

Since the GRUB doesn't attempt to detect if the filesystem is inconsistent
nor replays the journal, just ignore if a filesystem needs to be repaired.

For this reason, make it a best effort but print a debug message when the
XFS filesystem is accessed if should be repaired. That way, if the reading
or later booting fail, the user can figure out that may be related to this.

Suggested-by: Eric Sandeen <esandeen@redhat.com>
Signed-off-by: Javier Martinez Canillas <javierm@redhat.com>
---

Changes in v2:
- Improve commit message of patch #4 (dkiper).
- Fix typo in debug message of patch #4 (dkiper).

 grub-core/fs/xfs.c | 17 ++++++++++++++++-
 1 file changed, 16 insertions(+), 1 deletion(-)

diff --git a/grub-core/fs/xfs.c b/grub-core/fs/xfs.c
index bcf281cf80d..6056bf44e32 100644
--- a/grub-core/fs/xfs.c
+++ b/grub-core/fs/xfs.c
@@ -84,6 +84,7 @@ GRUB_MOD_LICENSE ("GPLv3+");
 #define XFS_SB_FEAT_INCOMPAT_SPINODES   (1 << 1)        /* sparse inode chunks 
*/
 #define XFS_SB_FEAT_INCOMPAT_META_UUID  (1 << 2)        /* metadata UUID */
 #define XFS_SB_FEAT_INCOMPAT_BIGTIME    (1 << 3)        /* large timestamps */
+#define XFS_SB_FEAT_INCOMPAT_NEEDSREPAIR (1 << 4)       /* needs xfs_repair */
 
 /*
  * Directory entries with ftype are explicitly handled by GRUB code.
@@ -98,7 +99,8 @@ GRUB_MOD_LICENSE ("GPLv3+");
        (XFS_SB_FEAT_INCOMPAT_FTYPE | \
         XFS_SB_FEAT_INCOMPAT_SPINODES | \
         XFS_SB_FEAT_INCOMPAT_META_UUID | \
-        XFS_SB_FEAT_INCOMPAT_BIGTIME)
+        XFS_SB_FEAT_INCOMPAT_BIGTIME | \
+        XFS_SB_FEAT_INCOMPAT_NEEDSREPAIR)
 
 struct grub_xfs_sblock
 {
@@ -307,6 +309,16 @@ static int grub_xfs_sb_valid(struct grub_xfs_data *data)
   return 0;
 }
 
+static int
+grub_xfs_sb_needs_repair (struct grub_xfs_data *data)
+{
+  return ((data->sblock.version &
+           grub_cpu_to_be16_compile_time (XFS_SB_VERSION_NUMBITS)) ==
+          grub_cpu_to_be16_compile_time (XFS_SB_VERSION_5) &&
+          (data->sblock.sb_features_incompat &
+           grub_cpu_to_be32_compile_time (XFS_SB_FEAT_INCOMPAT_NEEDSREPAIR)));
+}
+
 /* Filetype information as used in inodes.  */
 #define FILETYPE_INO_MASK      0170000
 #define FILETYPE_INO_REG       0100000
@@ -922,6 +934,9 @@ grub_xfs_mount (grub_disk_t disk)
   if (!grub_xfs_sb_valid(data))
     goto fail;
 
+  if (grub_xfs_sb_needs_repair (data))
+    grub_dprintf ("xfs", "XFS filesystem needs repair, can lead to 
failures\n");
+
   if (grub_add (grub_xfs_inode_size (data),
       sizeof (struct grub_xfs_data) - sizeof (struct grub_xfs_inode) + 1, &sz))
     goto fail;
-- 
2.31.1