[2.06 RELEASE PATCH 3/3] fs/xfs: Add needsrepair incompat feature support

[Javier Martinez Canillas]

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

But print a message if grub_xfs_mount() fails, to give more information to
the user about why that could had been the case.

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

 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 2ce76ec70f9..9e290a144a0 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", "Filesystem needs repair, could cause reads to 
fail\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