xfs: support the XFS_BTNUM_FINOBT free inode btree type

Define the AGI fields for the finobt root/level and add magic
numbers. Update the btree code to add support for the new
XFS_BTNUM_FINOBT inode btree.

The finobt root block is reserved immediately following the inobt
root block in the AG. Update XFS_PREALLOC_BLOCKS() to determine the
starting AG data block based on whether finobt support is enabled.

Signed-off-by: Brian Foster <bfoster@redhat.com>
Reviewed-by: Dave Chinner <dchinner@redhat.com>
Signed-off-by: Dave Chinner <david@fromorbit.com>

1 files changed, 32 insertions, 6 deletions

diff --git a/fs/xfs/xfs_ialloc.c b/fs/xfs/xfs_ialloc.c
index e67657288b9a..a0aead57a341 100644
--- a/fs/xfs/xfs_ialloc.c
+++ b/fs/xfs/xfs_ialloc.c
@@ -1488,7 +1488,16 @@ xfs_ialloc_compute_maxlevels(
 }
 
 /*
- * Log specified fields for the ag hdr (inode section)
+ * Log specified fields for the ag hdr (inode section). The growth of the agi
+ * structure over time requires that we interpret the buffer as two logical
+ * regions delineated by the end of the unlinked list. This is due to the size
+ * of the hash table and its location in the middle of the agi.
+ *
+ * For example, a request to log a field before agi_unlinked and a field after
+ * agi_unlinked could cause us to log the entire hash table and use an excessive
+ * amount of log space. To avoid this behavior, log the region up through
+ * agi_unlinked in one call and the region after agi_unlinked through the end of
+ * the structure in another.
  */
 void
 xfs_ialloc_log_agi(
@@ -1511,6 +1520,8 @@ xfs_ialloc_log_agi(
                 offsetof(xfs_agi_t, agi_newino),
                 offsetof(xfs_agi_t, agi_dirino),
                 offsetof(xfs_agi_t, agi_unlinked),
+                offsetof(xfs_agi_t, agi_free_root),
+                offsetof(xfs_agi_t, agi_free_level),
                 sizeof(xfs_agi_t)
         };
 #ifdef DEBUG
@@ -1519,15 +1530,30 @@ xfs_ialloc_log_agi(
         agi = XFS_BUF_TO_AGI(bp);
         ASSERT(agi->agi_magicnum == cpu_to_be32(XFS_AGI_MAGIC));
 #endif
+
+        xfs_trans_buf_set_type(tp, bp, XFS_BLFT_AGI_BUF);
+
         /*
-         * Compute byte offsets for the first and last fields.
+         * Compute byte offsets for the first and last fields in the first
+         * region and log the agi buffer. This only logs up through
+         * agi_unlinked.
          */
-        xfs_btree_offsets(fields, offsets, XFS_AGI_NUM_BITS, &first, &last);
+        if (fields & XFS_AGI_ALL_BITS_R1) {
+                xfs_btree_offsets(fields, offsets, XFS_AGI_NUM_BITS_R1,
+                                  &first, &last);
+                xfs_trans_log_buf(tp, bp, first, last);
+        }
+
         /*
-         * Log the allocation group inode header buffer.
+         * Mask off the bits in the first region and calculate the first and
+         * last field offsets for any bits in the second region.
          */
-        xfs_trans_buf_set_type(tp, bp, XFS_BLFT_AGI_BUF);
-        xfs_trans_log_buf(tp, bp, first, last);
+        fields &= ~XFS_AGI_ALL_BITS_R1;
+        if (fields) {
+                xfs_btree_offsets(fields, offsets, XFS_AGI_NUM_BITS_R2,
+                                  &first, &last);
+                xfs_trans_log_buf(tp, bp, first, last);
+        }
 }
 
 #ifdef DEBUG