xfs: introduce xfs_mod_frextents

Add a new helper to modify the incore counter of free realtime
extents. This matches the helpers used for inode and data block
counters, and removes a significant users of the xfs_mod_incore_sb()
interface.

Based on a patch originally from Christoph Hellwig.

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

4 files changed, 34 insertions, 21 deletions

diff --git a/fs/xfs/libxfs/xfs_bmap.c b/fs/xfs/libxfs/xfs_bmap.c
index e39c9e83670e..b8e97fd0bac1 100644
--- a/fs/xfs/libxfs/xfs_bmap.c
+++ b/fs/xfs/libxfs/xfs_bmap.c
@@ -4158,8 +4158,7 @@ xfs_bmapi_reserve_delalloc(
         ASSERT(indlen > 0);
 
         if (rt) {
-                error = xfs_mod_incore_sb(mp, XFS_SBS_FREXTENTS,
-                                          -((int64_t)extsz), 0);
+                error = xfs_mod_frextents(mp, -((int64_t)extsz));
         } else {
                 error = xfs_mod_fdblocks(mp, -((int64_t)alen), false);
         }
@@ -4194,7 +4193,7 @@ xfs_bmapi_reserve_delalloc(
 
 out_unreserve_blocks:
         if (rt)
-                xfs_mod_incore_sb(mp, XFS_SBS_FREXTENTS, extsz, 0);
+                xfs_mod_frextents(mp, extsz);
         else
                 xfs_mod_fdblocks(mp, alen, false);
 out_unreserve_quota:
@@ -5278,8 +5277,7 @@ xfs_bunmapi(
 
                                 rtexts = XFS_FSB_TO_B(mp, del.br_blockcount);
                                 do_div(rtexts, mp->m_sb.sb_rextsize);
-                                xfs_mod_incore_sb(mp, XFS_SBS_FREXTENTS,
-                                                (int64_t)rtexts, 0);
+                                xfs_mod_frextents(mp, (int64_t)rtexts);
                                 (void)xfs_trans_reserve_quota_nblks(NULL,
                                         ip, -((long)del.br_blockcount), 0,
                                         XFS_QMOPT_RES_RTBLKS);
diff --git a/fs/xfs/xfs_mount.c b/fs/xfs/xfs_mount.c
index 05b392e35e35..df4c32fdc706 100644
--- a/fs/xfs/xfs_mount.c
+++ b/fs/xfs/xfs_mount.c
@@ -1198,6 +1198,24 @@ fdblocks_enospc:
         return -ENOSPC;
 }
 
+int
+xfs_mod_frextents(
+        struct xfs_mount        *mp,
+        int64_t                 delta)
+{
+        int64_t                 lcounter;
+        int                     ret = 0;
+
+        spin_lock(&mp->m_sb_lock);
+        lcounter = mp->m_sb.sb_frextents + delta;
+        if (lcounter < 0)
+                ret = -ENOSPC;
+        else
+                mp->m_sb.sb_frextents = lcounter;
+        spin_unlock(&mp->m_sb_lock);
+        return ret;
+}
+
 /*
  * xfs_mod_incore_sb_unlocked() is a utility routine commonly used to apply
  * a delta to a specified field in the in-core superblock.  Simply
@@ -1227,16 +1245,9 @@ xfs_mod_incore_sb_unlocked(
         case XFS_SBS_ICOUNT:
         case XFS_SBS_IFREE:
         case XFS_SBS_FDBLOCKS:
+        case XFS_SBS_FREXTENTS:
                 ASSERT(0);
                 return -EINVAL;
-        case XFS_SBS_FREXTENTS:
-                lcounter = (long long)mp->m_sb.sb_frextents;
-                lcounter += delta;
-                if (lcounter < 0) {
-                        return -ENOSPC;
-                }
-                mp->m_sb.sb_frextents = lcounter;
-                return 0;
         case XFS_SBS_DBLOCKS:
                 lcounter = (long long)mp->m_sb.sb_dblocks;
                 lcounter += delta;
diff --git a/fs/xfs/xfs_mount.h b/fs/xfs/xfs_mount.h
index 205f23a240a7..d65e0f23b847 100644
--- a/fs/xfs/xfs_mount.h
+++ b/fs/xfs/xfs_mount.h
@@ -331,6 +331,8 @@ extern int	xfs_mod_icount(struct xfs_mount *mp, int64_t delta);
 extern int      xfs_mod_ifree(struct xfs_mount *mp, int64_t delta);
 extern int      xfs_mod_fdblocks(struct xfs_mount *mp, int64_t delta,
                                  bool reserved);
+extern int      xfs_mod_frextents(struct xfs_mount *mp, int64_t delta);
+
 extern int      xfs_mount_log_sb(xfs_mount_t *);
 extern struct xfs_buf *xfs_getsb(xfs_mount_t *, int);
 extern int      xfs_readsb(xfs_mount_t *, int);
diff --git a/fs/xfs/xfs_trans.c b/fs/xfs/xfs_trans.c
index e99f5e552c64..4e4bc5aed6b6 100644
--- a/fs/xfs/xfs_trans.c
+++ b/fs/xfs/xfs_trans.c
@@ -235,8 +235,7 @@ xfs_trans_reserve(
          * fail if the count would go below zero.
          */
         if (rtextents > 0) {
-                error = xfs_mod_incore_sb(tp->t_mountp, XFS_SBS_FREXTENTS,
-                                          -((int64_t)rtextents), rsvd);
+                error = xfs_mod_frextents(tp->t_mountp, -((int64_t)rtextents));
                 if (error) {
                         error = -ENOSPC;
                         goto undo_log;
@@ -562,10 +561,10 @@ xfs_trans_unreserve_and_mod_sb(
         }
 
         /* apply remaining deltas */
-        if (rtxdelta != 0) {
-                msbp->msb_field = XFS_SBS_FREXTENTS;
-                msbp->msb_delta = rtxdelta;
-                msbp++;
+        if (rtxdelta) {
+                error = xfs_mod_frextents(mp, rtxdelta);
+                if (error)
+                        goto out_undo_ifree;
         }
 
         if (tp->t_flags & XFS_TRANS_SB_DIRTY) {
@@ -618,12 +617,15 @@ xfs_trans_unreserve_and_mod_sb(
                 error = xfs_mod_incore_sb_batch(tp->t_mountp, msb,
                         (uint)(msbp - msb), rsvd);
                 if (error)
-                        goto out_undo_ifreecount;
+                        goto out_undo_frextents;
         }
 
         return;
 
-out_undo_ifreecount:
+out_undo_frextents:
+        if (rtxdelta)
+                xfs_mod_frextents(mp, -rtxdelta);
+out_undo_ifree:
         if (ifreedelta)
                 xfs_mod_ifree(mp, -ifreedelta);
 out_undo_icount: