1 files changed, 81 insertions, 44 deletions

diff --git a/fs/xfs/xfs_trans.c b/fs/xfs/xfs_trans.c
index cc2d60951e21..356d6627f581 100644
--- a/fs/xfs/xfs_trans.c
+++ b/fs/xfs/xfs_trans.c
@@ -427,6 +427,14 @@ undo_blocks:
  *
  * Mark the transaction structure to indicate that the superblock
  * needs to be updated before committing.
+ *
+ * Because we may not be keeping track of allocated/free inodes and
+ * used filesystem blocks in the superblock, we do not mark the
+ * superblock dirty in this transaction if we modify these fields.
+ * We still need to update the transaction deltas so that they get
+ * applied to the incore superblock, but we don't want them to
+ * cause the superblock to get locked and logged if these are the
+ * only fields in the superblock that the transaction modifies.
  */
 void
 xfs_trans_mod_sb(
@@ -434,13 +442,19 @@ xfs_trans_mod_sb(
         uint            field,
         int64_t         delta)
 {
+        uint32_t        flags = (XFS_TRANS_DIRTY|XFS_TRANS_SB_DIRTY);
+        xfs_mount_t     *mp = tp->t_mountp;
 
         switch (field) {
         case XFS_TRANS_SB_ICOUNT:
                 tp->t_icount_delta += delta;
+                if (xfs_sb_version_haslazysbcount(&mp->m_sb))
+                        flags &= ~XFS_TRANS_SB_DIRTY;
                 break;
         case XFS_TRANS_SB_IFREE:
                 tp->t_ifree_delta += delta;
+                if (xfs_sb_version_haslazysbcount(&mp->m_sb))
+                        flags &= ~XFS_TRANS_SB_DIRTY;
                 break;
         case XFS_TRANS_SB_FDBLOCKS:
                 /*
@@ -453,6 +467,8 @@ xfs_trans_mod_sb(
                         ASSERT(tp->t_blk_res_used <= tp->t_blk_res);
                 }
                 tp->t_fdblocks_delta += delta;
+                if (xfs_sb_version_haslazysbcount(&mp->m_sb))
+                        flags &= ~XFS_TRANS_SB_DIRTY;
                 break;
         case XFS_TRANS_SB_RES_FDBLOCKS:
                 /*
@@ -462,6 +478,8 @@ xfs_trans_mod_sb(
                  */
                 ASSERT(delta < 0);
                 tp->t_res_fdblocks_delta += delta;
+                if (xfs_sb_version_haslazysbcount(&mp->m_sb))
+                        flags &= ~XFS_TRANS_SB_DIRTY;
                 break;
         case XFS_TRANS_SB_FREXTENTS:
                 /*
@@ -515,7 +533,7 @@ xfs_trans_mod_sb(
                 return;
         }
 
-        tp->t_flags |= (XFS_TRANS_SB_DIRTY | XFS_TRANS_DIRTY);
+        tp->t_flags |= flags;
 }
 
 /*
@@ -544,18 +562,23 @@ xfs_trans_apply_sb_deltas(
                (tp->t_ag_freeblks_delta + tp->t_ag_flist_delta +
                 tp->t_ag_btree_delta));
 
-        if (tp->t_icount_delta != 0) {
-                INT_MOD(sbp->sb_icount, ARCH_CONVERT, tp->t_icount_delta);
-        }
-        if (tp->t_ifree_delta != 0) {
-                INT_MOD(sbp->sb_ifree, ARCH_CONVERT, tp->t_ifree_delta);
-        }
+        /*
+         * Only update the superblock counters if we are logging them
+         */
+        if (!xfs_sb_version_haslazysbcount(&(tp->t_mountp->m_sb))) {
+                if (tp->t_icount_delta != 0) {
+                        INT_MOD(sbp->sb_icount, ARCH_CONVERT, tp->t_icount_delta);
+                }
+                if (tp->t_ifree_delta != 0) {
+                        INT_MOD(sbp->sb_ifree, ARCH_CONVERT, tp->t_ifree_delta);
+                }
 
-        if (tp->t_fdblocks_delta != 0) {
-                INT_MOD(sbp->sb_fdblocks, ARCH_CONVERT, tp->t_fdblocks_delta);
-        }
-        if (tp->t_res_fdblocks_delta != 0) {
-                INT_MOD(sbp->sb_fdblocks, ARCH_CONVERT, tp->t_res_fdblocks_delta);
+                if (tp->t_fdblocks_delta != 0) {
+                        INT_MOD(sbp->sb_fdblocks, ARCH_CONVERT, tp->t_fdblocks_delta);
+                }
+                if (tp->t_res_fdblocks_delta != 0) {
+                        INT_MOD(sbp->sb_fdblocks, ARCH_CONVERT, tp->t_res_fdblocks_delta);
+                }
         }
 
         if (tp->t_frextents_delta != 0) {
@@ -615,11 +638,23 @@ xfs_trans_apply_sb_deltas(
 }
 
 /*
- * xfs_trans_unreserve_and_mod_sb() is called to release unused
- * reservations and apply superblock counter changes to the in-core
- * superblock.
+ * xfs_trans_unreserve_and_mod_sb() is called to release unused reservations
+ * and apply superblock counter changes to the in-core superblock.  The
+ * t_res_fdblocks_delta and t_res_frextents_delta fields are explicitly NOT
+ * applied to the in-core superblock.  The idea is that that has already been
+ * done.
  *
  * This is done efficiently with a single call to xfs_mod_incore_sb_batch().
+ * However, we have to ensure that we only modify each superblock field only
+ * once because the application of the delta values may not be atomic. That can
+ * lead to ENOSPC races occurring if we have two separate modifcations of the
+ * free space counter to put back the entire reservation and then take away
+ * what we used.
+ *
+ * If we are not logging superblock counters, then the inode allocated/free and
+ * used block counts are not updated in the on disk superblock. In this case,
+ * XFS_TRANS_SB_DIRTY will not be set when the transaction is updated but we
+ * still need to update the incore superblock with the changes.
  */
 STATIC void
 xfs_trans_unreserve_and_mod_sb(
@@ -627,40 +662,49 @@ xfs_trans_unreserve_and_mod_sb(
 {
         xfs_mod_sb_t    msb[14];        /* If you add cases, add entries */
         xfs_mod_sb_t    *msbp;
+        xfs_mount_t     *mp = tp->t_mountp;
         /* REFERENCED */
         int             error;
         int             rsvd;
+        int64_t         blkdelta = 0;
+        int64_t         rtxdelta = 0;
 
         msbp = msb;
         rsvd = (tp->t_flags & XFS_TRANS_RESERVE) != 0;
 
-        /*
-         * Release any reserved blocks.  Any that were allocated
-         * will be taken back again by fdblocks_delta below.
-         */
-        if (tp->t_blk_res > 0) {
+        /* calculate free blocks delta */
+        if (tp->t_blk_res > 0)
+                blkdelta = tp->t_blk_res;
+
+        if ((tp->t_fdblocks_delta != 0) &&
+            (xfs_sb_version_haslazysbcount(&mp->m_sb) ||
+             (tp->t_flags & XFS_TRANS_SB_DIRTY)))
+                blkdelta += tp->t_fdblocks_delta;
+
+        if (blkdelta != 0) {
                 msbp->msb_field = XFS_SBS_FDBLOCKS;
-                msbp->msb_delta = tp->t_blk_res;
+                msbp->msb_delta = blkdelta;
                 msbp++;
         }
 
-        /*
-         * Release any reserved real time extents .  Any that were
-         * allocated will be taken back again by frextents_delta below.
-         */
-        if (tp->t_rtx_res > 0) {
+        /* calculate free realtime extents delta */
+        if (tp->t_rtx_res > 0)
+                rtxdelta = tp->t_rtx_res;
+
+        if ((tp->t_frextents_delta != 0) &&
+            (tp->t_flags & XFS_TRANS_SB_DIRTY))
+                rtxdelta += tp->t_frextents_delta;
+
+        if (rtxdelta != 0) {
                 msbp->msb_field = XFS_SBS_FREXTENTS;
-                msbp->msb_delta = tp->t_rtx_res;
+                msbp->msb_delta = rtxdelta;
                 msbp++;
         }
 
-        /*
-         * Apply any superblock modifications to the in-core version.
-         * The t_res_fdblocks_delta and t_res_frextents_delta fields are
-         * explicitly NOT applied to the in-core superblock.
-         * The idea is that that has already been done.
-         */
-        if (tp->t_flags & XFS_TRANS_SB_DIRTY) {
+        /* apply remaining deltas */
+
+        if (xfs_sb_version_haslazysbcount(&mp->m_sb) ||
+             (tp->t_flags & XFS_TRANS_SB_DIRTY)) {
                 if (tp->t_icount_delta != 0) {
                         msbp->msb_field = XFS_SBS_ICOUNT;
                         msbp->msb_delta = tp->t_icount_delta;
@@ -671,16 +715,9 @@ xfs_trans_unreserve_and_mod_sb(
                         msbp->msb_delta = tp->t_ifree_delta;
                         msbp++;
                 }
-                if (tp->t_fdblocks_delta != 0) {
-                        msbp->msb_field = XFS_SBS_FDBLOCKS;
-                        msbp->msb_delta = tp->t_fdblocks_delta;
-                        msbp++;
-                }
-                if (tp->t_frextents_delta != 0) {
-                        msbp->msb_field = XFS_SBS_FREXTENTS;
-                        msbp->msb_delta = tp->t_frextents_delta;
-                        msbp++;
-                }
+        }
+
+        if (tp->t_flags & XFS_TRANS_SB_DIRTY) {
                 if (tp->t_dblocks_delta != 0) {
                         msbp->msb_field = XFS_SBS_DBLOCKS;
                         msbp->msb_delta = tp->t_dblocks_delta;