xfs: factor out MRU hit case in xfs_filestream_select_ag

Because it now stands out like a sore thumb. Factoring out this case
starts the process of simplifying xfs_filestream_select_ag() again.

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

diff --git a/fs/xfs/xfs_filestream.c b/fs/xfs/xfs_filestream.c
index 95e28aa..147296a 100644 (file)
--- a/fs/xfs/xfs_filestream.c
+++ b/fs/xfs/xfs_filestream.c
@@ -260,9 +260,84 @@ out:
 }
 
 /*
+ * Lookup the mru cache for an existing association. If one exists and we can
+ * use it, return with the agno and blen indicating that the allocation will
+ * proceed with that association.
+ *
+ * If we have no association, or we cannot use the current one and have to
+ * destroy it, return with blen = 0 and agno pointing at the next agno to try.
+ */
+int
+xfs_filestream_select_ag_mru(
+       struct xfs_bmalloca     *ap,
+       struct xfs_alloc_arg    *args,
+       struct xfs_inode        *pip,
+       xfs_agnumber_t          *agno,
+       xfs_extlen_t            *blen)
+{
+       struct xfs_mount        *mp = ap->ip->i_mount;
+       struct xfs_perag        *pag;
+       struct xfs_mru_cache_elem *mru;
+       int                     error;
+
+       mru = xfs_mru_cache_lookup(mp->m_filestream, pip->i_ino);
+       if (!mru)
+               goto out_default_agno;
+
+       *agno = container_of(mru, struct xfs_fstrm_item, mru)->ag;
+       xfs_mru_cache_done(mp->m_filestream);
+
+       trace_xfs_filestream_lookup(mp, ap->ip->i_ino, *agno);
+
+       ap->blkno = XFS_AGB_TO_FSB(args->mp, *agno, 0);
+       xfs_bmap_adjacent(ap);
+
+       pag = xfs_perag_grab(mp, *agno);
+       if (!pag)
+               goto out_default_agno;
+
+       error = xfs_bmap_longest_free_extent(pag, args->tp, blen);
+       xfs_perag_rele(pag);
+       if (error) {
+               if (error != -EAGAIN)
+                       return error;
+               *blen = 0;
+       }
+
+       /*
+        * We are done if there's still enough contiguous free space to succeed.
+        */
+       if (*blen >= args->maxlen)
+               return 0;
+
+       /* Changing parent AG association now, so remove the existing one. */
+       mru = xfs_mru_cache_remove(mp->m_filestream, pip->i_ino);
+       if (mru) {
+               struct xfs_fstrm_item *item =
+                       container_of(mru, struct xfs_fstrm_item, mru);
+               *agno = (item->ag + 1) % mp->m_sb.sb_agcount;
+               xfs_fstrm_free_func(mp, mru);
+               return 0;
+       }
+
+out_default_agno:
+       if (xfs_is_inode32(mp)) {
+               xfs_agnumber_t   rotorstep = xfs_rotorstep;
+               *agno = (mp->m_agfrotor / rotorstep) %
+                               mp->m_sb.sb_agcount;
+               mp->m_agfrotor = (mp->m_agfrotor + 1) %
+                                (mp->m_sb.sb_agcount * rotorstep);
+               return 0;
+       }
+       *agno = XFS_INO_TO_AGNO(mp, pip->i_ino);
+       return 0;
+
+}
+
+/*
  * Search for an allocation group with a single extent large enough for
- * the request.  If one isn't found, then the largest available free extent is
- * returned as the best length possible.
+ * the request.  If one isn't found, then adjust the minimum allocation
+ * size to the largest space found.
  */
 int
 xfs_filestream_select_ag(
@@ -271,12 +346,10 @@ xfs_filestream_select_ag(
        xfs_extlen_t            *blen)
 {
        struct xfs_mount        *mp = ap->ip->i_mount;
-       struct xfs_perag        *pag;
        struct xfs_inode        *pip = NULL;
-       xfs_agnumber_t          agno = NULLAGNUMBER;
-       struct xfs_mru_cache_elem *mru;
+       xfs_agnumber_t          agno;
        int                     flags = 0;
-       int                     error = 0;
+       int                     error;
 
        args->total = ap->total;
        *blen = 0;
@@ -287,48 +360,10 @@ xfs_filestream_select_ag(
                goto out_select;
        }
 
-       mru = xfs_mru_cache_lookup(mp->m_filestream, pip->i_ino);
-       if (mru) {
-               agno = container_of(mru, struct xfs_fstrm_item, mru)->ag;
-               xfs_mru_cache_done(mp->m_filestream);
-               mru = NULL;
-
-               trace_xfs_filestream_lookup(mp, ap->ip->i_ino, agno);
-               xfs_irele(pip);
-
-               ap->blkno = XFS_AGB_TO_FSB(args->mp, agno, 0);
-               xfs_bmap_adjacent(ap);
-
-               pag = xfs_perag_grab(mp, agno);
-               if (pag) {
-                       error = xfs_bmap_longest_free_extent(pag, args->tp, blen);
-                       xfs_perag_rele(pag);
-                       if (error) {
-                               if (error != -EAGAIN)
-                                       goto out_error;
-                               *blen = 0;
-                       }
-               }
-               if (*blen >= args->maxlen)
-                       goto out_select;
-       } else if (xfs_is_inode32(mp)) {
-               xfs_agnumber_t   rotorstep = xfs_rotorstep;
-               agno = (mp->m_agfrotor / rotorstep) %
-                               mp->m_sb.sb_agcount;
-               mp->m_agfrotor = (mp->m_agfrotor + 1) %
-                                (mp->m_sb.sb_agcount * rotorstep);
-       } else {
-               agno = XFS_INO_TO_AGNO(mp, pip->i_ino);
-       }
+       error = xfs_filestream_select_ag_mru(ap, args, pip, &agno, blen);
+       if (error || *blen >= args->maxlen)
+               goto out_rele;
 
-       /* Changing parent AG association now, so remove the existing one. */
-       mru = xfs_mru_cache_remove(mp->m_filestream, pip->i_ino);
-       if (mru) {
-               struct xfs_fstrm_item *item =
-                       container_of(mru, struct xfs_fstrm_item, mru);
-               agno = (item->ag + 1) % mp->m_sb.sb_agcount;
-               xfs_fstrm_free_func(mp, mru);
-       }
        ap->blkno = XFS_AGB_TO_FSB(args->mp, agno, 0);
        xfs_bmap_adjacent(ap);
 
@@ -347,8 +382,6 @@ xfs_filestream_select_ag(
 
        *blen = ap->length;
        error = xfs_filestream_pick_ag(pip, &agno, flags, blen);
-       if (error)
-               goto out_error;
        if (agno == NULLAGNUMBER) {
                agno = 0;
                *blen = 0;
@@ -356,7 +389,7 @@ xfs_filestream_select_ag(
 
 out_select:
        ap->blkno = XFS_AGB_TO_FSB(mp, agno, 0);
-out_error:
+out_rele:
        xfs_irele(pip);
        return error;