xfs: convert trim to use for_each_perag_range

To convert it to using active perag references and hence make it
shrink safe.

Signed-off-by: Dave Chinner <dchinner@redhat.com>
Reviewed-by: Darrick J. Wong <djwong@kernel.org>

diff --git a/fs/xfs/xfs_discard.c b/fs/xfs/xfs_discard.c
index bfc829c..afc4c78 100644 (file)
--- a/fs/xfs/xfs_discard.c
+++ b/fs/xfs/xfs_discard.c
@@ -21,23 +21,20 @@
 
 STATIC int
 xfs_trim_extents(
-       struct xfs_mount        *mp,
-       xfs_agnumber_t          agno,
+       struct xfs_perag        *pag,
        xfs_daddr_t             start,
        xfs_daddr_t             end,
        xfs_daddr_t             minlen,
        uint64_t                *blocks_trimmed)
 {
+       struct xfs_mount        *mp = pag->pag_mount;
        struct block_device     *bdev = mp->m_ddev_targp->bt_bdev;
        struct xfs_btree_cur    *cur;
        struct xfs_buf          *agbp;
        struct xfs_agf          *agf;
-       struct xfs_perag        *pag;
        int                     error;
        int                     i;
 
-       pag = xfs_perag_get(mp, agno);
-
        /*
         * Force out the log.  This means any transactions that might have freed
         * space before we take the AGF buffer lock are now on disk, and the
@@ -47,7 +44,7 @@ xfs_trim_extents(
 
        error = xfs_alloc_read_agf(pag, NULL, 0, &agbp);
        if (error)
-               goto out_put_perag;
+               return error;
        agf = agbp->b_addr;
 
        cur = xfs_allocbt_init_cursor(mp, NULL, agbp, pag, XFS_BTNUM_CNT);
@@ -71,10 +68,10 @@ xfs_trim_extents(
 
                error = xfs_alloc_get_rec(cur, &fbno, &flen, &i);
                if (error)
-                       goto out_del_cursor;
+                       break;
                if (XFS_IS_CORRUPT(mp, i != 1)) {
                        error = -EFSCORRUPTED;
-                       goto out_del_cursor;
+                       break;
                }
                ASSERT(flen <= be32_to_cpu(agf->agf_longest));
 
@@ -83,15 +80,15 @@ xfs_trim_extents(
                 * the format the range/len variables are supplied in by
                 * userspace.
                 */
-               dbno = XFS_AGB_TO_DADDR(mp, agno, fbno);
+               dbno = XFS_AGB_TO_DADDR(mp, pag->pag_agno, fbno);
                dlen = XFS_FSB_TO_BB(mp, flen);
 
                /*
                 * Too small?  Give up.
                 */
                if (dlen < minlen) {
-                       trace_xfs_discard_toosmall(mp, agno, fbno, flen);
-                       goto out_del_cursor;
+                       trace_xfs_discard_toosmall(mp, pag->pag_agno, fbno, flen);
+                       break;
                }
 
                /*
@@ -100,7 +97,7 @@ xfs_trim_extents(
                 * down partially overlapping ranges for now.
                 */
                if (dbno + dlen < start || dbno > end) {
-                       trace_xfs_discard_exclude(mp, agno, fbno, flen);
+                       trace_xfs_discard_exclude(mp, pag->pag_agno, fbno, flen);
                        goto next_extent;
                }
 
@@ -109,32 +106,30 @@ xfs_trim_extents(
                 * discard and try again the next time.
                 */
                if (xfs_extent_busy_search(mp, pag, fbno, flen)) {
-                       trace_xfs_discard_busy(mp, agno, fbno, flen);
+                       trace_xfs_discard_busy(mp, pag->pag_agno, fbno, flen);
                        goto next_extent;
                }
 
-               trace_xfs_discard_extent(mp, agno, fbno, flen);
+               trace_xfs_discard_extent(mp, pag->pag_agno, fbno, flen);
                error = blkdev_issue_discard(bdev, dbno, dlen, GFP_NOFS);
                if (error)
-                       goto out_del_cursor;
+                       break;
                *blocks_trimmed += flen;
 
 next_extent:
                error = xfs_btree_decrement(cur, 0, &i);
                if (error)
-                       goto out_del_cursor;
+                       break;
 
                if (fatal_signal_pending(current)) {
                        error = -ERESTARTSYS;
-                       goto out_del_cursor;
+                       break;
                }
        }
 
 out_del_cursor:
        xfs_btree_del_cursor(cur, error);
        xfs_buf_relse(agbp);
-out_put_perag:
-       xfs_perag_put(pag);
        return error;
 }
 
@@ -152,11 +147,12 @@ xfs_ioc_trim(
        struct xfs_mount                *mp,
        struct fstrim_range __user      *urange)
 {
+       struct xfs_perag        *pag;
        unsigned int            granularity =
                bdev_discard_granularity(mp->m_ddev_targp->bt_bdev);
        struct fstrim_range     range;
        xfs_daddr_t             start, end, minlen;
-       xfs_agnumber_t          start_agno, end_agno, agno;
+       xfs_agnumber_t          agno;
        uint64_t                blocks_trimmed = 0;
        int                     error, last_error = 0;
 
@@ -193,18 +189,18 @@ xfs_ioc_trim(
        end = start + BTOBBT(range.len) - 1;
 
        if (end > XFS_FSB_TO_BB(mp, mp->m_sb.sb_dblocks) - 1)
-               end = XFS_FSB_TO_BB(mp, mp->m_sb.sb_dblocks)- 1;
-
-       start_agno = xfs_daddr_to_agno(mp, start);
-       end_agno = xfs_daddr_to_agno(mp, end);
+               end = XFS_FSB_TO_BB(mp, mp->m_sb.sb_dblocks) - 1;
 
-       for (agno = start_agno; agno <= end_agno; agno++) {
-               error = xfs_trim_extents(mp, agno, start, end, minlen,
+       agno = xfs_daddr_to_agno(mp, start);
+       for_each_perag_range(mp, agno, xfs_daddr_to_agno(mp, end), pag) {
+               error = xfs_trim_extents(pag, start, end, minlen,
                                          &blocks_trimmed);
                if (error) {
                        last_error = error;
-                       if (error == -ERESTARTSYS)
+                       if (error == -ERESTARTSYS) {
+                               xfs_perag_rele(pag);
                                break;
+                       }
                }
        }