xfs: do not use xfs_mod_incore_sb_batch for per-cpu counters

Update the per-cpu counters manually in xfs_trans_unreserve_and_mod_sb
and remove support for per-cpu counters from xfs_mod_incore_sb_batch
to simplify it.  And added benefit is that we don't have to take
m_sb_lock for transactions that only modify per-cpu counters.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Alex Elder <aelder@sgi.com>

1 files changed, 35 insertions, 79 deletions

diff --git a/fs/xfs/xfs_mount.c b/fs/xfs/xfs_mount.c
index 20c67ff57536..00538b7e694a 100644
--- a/fs/xfs/xfs_mount.c
+++ b/fs/xfs/xfs_mount.c
@@ -1856,98 +1856,54 @@ xfs_mod_incore_sb(
 }
 
 /*
- * xfs_mod_incore_sb_batch() is used to change more than one field
- * in the in-core superblock structure at a time.  This modification
- * is protected by a lock internal to this module.  The fields and
- * changes to those fields are specified in the array of xfs_mod_sb
- * structures passed in.
+ * Change more than one field in the in-core superblock structure at a time.
  *
- * Either all of the specified deltas will be applied or none of
- * them will.  If any modified field dips below 0, then all modifications
- * will be backed out and EINVAL will be returned.
+ * The fields and changes to those fields are specified in the array of
+ * xfs_mod_sb structures passed in.  Either all of the specified deltas
+ * will be applied or none of them will.  If any modified field dips below 0,
+ * then all modifications will be backed out and EINVAL will be returned.
+ *
+ * Note that this function may not be used for the superblock values that
+ * are tracked with the in-memory per-cpu counters - a direct call to
+ * xfs_icsb_modify_counters is required for these.
  */
 int
-xfs_mod_incore_sb_batch(xfs_mount_t *mp, xfs_mod_sb_t *msb, uint nmsb, int rsvd)
+xfs_mod_incore_sb_batch(
+        struct xfs_mount        *mp,
+        xfs_mod_sb_t            *msb,
+        uint                    nmsb,
+        int                     rsvd)
 {
-        int             status=0;
-        xfs_mod_sb_t    *msbp;
+        xfs_mod_sb_t            *msbp = &msb[0];
+        int                     error = 0;
 
         /*
-         * Loop through the array of mod structures and apply each
-         * individually.  If any fail, then back out all those
-         * which have already been applied.  Do all of this within
-         * the scope of the m_sb_lock so that all of the changes will
-         * be atomic.
+         * Loop through the array of mod structures and apply each individually.
+         * If any fail, then back out all those which have already been applied.
+         * Do all of this within the scope of the m_sb_lock so that all of the
+         * changes will be atomic.
          */
         spin_lock(&mp->m_sb_lock);
-        msbp = &msb[0];
         for (msbp = &msbp[0]; msbp < (msb + nmsb); msbp++) {
-                /*
-                 * Apply the delta at index n.  If it fails, break
-                 * from the loop so we'll fall into the undo loop
-                 * below.
-                 */
-                switch (msbp->msb_field) {
-#ifdef HAVE_PERCPU_SB
-                case XFS_SBS_ICOUNT:
-                case XFS_SBS_IFREE:
-                case XFS_SBS_FDBLOCKS:
-                        spin_unlock(&mp->m_sb_lock);
-                        status = xfs_icsb_modify_counters(mp,
-                                                msbp->msb_field,
-                                                msbp->msb_delta, rsvd);
-                        spin_lock(&mp->m_sb_lock);
-                        break;
-#endif
-                default:
-                        status = xfs_mod_incore_sb_unlocked(mp,
-                                                msbp->msb_field,
-                                                msbp->msb_delta, rsvd);
-                        break;
-                }
+                ASSERT(msbp->msb_field < XFS_SBS_ICOUNT ||
+                       msbp->msb_field > XFS_SBS_FDBLOCKS);
 
-                if (status != 0) {
-                        break;
-                }
+                error = xfs_mod_incore_sb_unlocked(mp, msbp->msb_field,
+                                                   msbp->msb_delta, rsvd);
+                if (error)
+                        goto unwind;
         }
+        spin_unlock(&mp->m_sb_lock);
+        return 0;
 
-        /*
-         * If we didn't complete the loop above, then back out
-         * any changes made to the superblock.  If you add code
-         * between the loop above and here, make sure that you
-         * preserve the value of status. Loop back until
-         * we step below the beginning of the array.  Make sure
-         * we don't touch anything back there.
-         */
-        if (status != 0) {
-                msbp--;
-                while (msbp >= msb) {
-                        switch (msbp->msb_field) {
-#ifdef HAVE_PERCPU_SB
-                        case XFS_SBS_ICOUNT:
-                        case XFS_SBS_IFREE:
-                        case XFS_SBS_FDBLOCKS:
-                                spin_unlock(&mp->m_sb_lock);
-                                status = xfs_icsb_modify_counters(mp,
-                                                msbp->msb_field,
-                                                -(msbp->msb_delta),
-                                                rsvd);
-                                spin_lock(&mp->m_sb_lock);
-                                break;
-#endif
-                        default:
-                                status = xfs_mod_incore_sb_unlocked(mp,
-                                                        msbp->msb_field,
-                                                        -(msbp->msb_delta),
-                                                        rsvd);
-                                break;
-                        }
-                        ASSERT(status == 0);
-                        msbp--;
-                }
+unwind:
+        while (--msbp >= msb) {
+                error = xfs_mod_incore_sb_unlocked(mp, msbp->msb_field,
+                                                   -msbp->msb_delta, rsvd);
+                ASSERT(error == 0);
         }
         spin_unlock(&mp->m_sb_lock);
-        return status;
+        return error;
 }
 
 /*
@@ -2478,7 +2434,7 @@ xfs_icsb_balance_counter(
         spin_unlock(&mp->m_sb_lock);
 }
 
-STATIC int
+int
 xfs_icsb_modify_counters(
         xfs_mount_t     *mp,
         xfs_sb_field_t  field,