xfs: simplify mappedbno handling in xfs_da_{get,read}_buf

Source kernel commit: fa0d44ec7faab82da468aa7ab4f0c2614cadf7e7

Shortcut the creation of xfs_bmbt_irec and xfs_buf_map for the case
where the callers passed an already mapped xfs_daddr_t.  This is in
preparation for splitting these cases out entirely later.  Also reject
the mappedbno case for xfs_da_reada_buf as no callers currently uses
it and it will be removed soon.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Darrick J. Wong <darrick.wong@oracle.com>
Signed-off-by: Darrick J. Wong <darrick.wong@oracle.com>
Signed-off-by: Eric Sandeen <sandeen@sandeen.net>

diff --git a/libxfs/xfs_da_btree.c b/libxfs/xfs_da_btree.c
index 1cf556058e11639bb6f31986afc8a18d8d363797..600869f2003b1b36f0a76773a4eaccf9d457347a 100644 (file)
--- a/libxfs/xfs_da_btree.c
+++ b/libxfs/xfs_da_btree.c
@@ -107,6 +107,13 @@ xfs_da_state_free(xfs_da_state_t *state)
        kmem_cache_free(xfs_da_state_zone, state);
 }
 
+static inline int xfs_dabuf_nfsb(struct xfs_mount *mp, int whichfork)
+{
+       if (whichfork == XFS_DATA_FORK)
+               return mp->m_dir_geo->fsbcount;
+       return mp->m_attr_geo->fsbcount;
+}
+
 void
 xfs_da3_node_hdr_from_disk(
        struct xfs_mount                *mp,
@@ -2536,7 +2543,7 @@ xfs_dabuf_map(
        int                     *nmaps)
 {
        struct xfs_mount        *mp = dp->i_mount;
-       int                     nfsb;
+       int                     nfsb = xfs_dabuf_nfsb(mp, whichfork);
        int                     error = 0;
        struct xfs_bmbt_irec    irec;
        struct xfs_bmbt_irec    *irecs = &irec;
@@ -2545,35 +2552,13 @@ xfs_dabuf_map(
        ASSERT(map && *map);
        ASSERT(*nmaps == 1);
 
-       if (whichfork == XFS_DATA_FORK)
-               nfsb = mp->m_dir_geo->fsbcount;
-       else
-               nfsb = mp->m_attr_geo->fsbcount;
-
-       /*
-        * Caller doesn't have a mapping.  -2 means don't complain
-        * if we land in a hole.
-        */
-       if (mappedbno == -1 || mappedbno == -2) {
-               /*
-                * Optimize the one-block case.
-                */
-               if (nfsb != 1)
-                       irecs = kmem_zalloc(sizeof(irec) * nfsb,
-                                           KM_NOFS);
-
-               nirecs = nfsb;
-               error = xfs_bmapi_read(dp, (xfs_fileoff_t)bno, nfsb, irecs,
-                                      &nirecs, xfs_bmapi_aflag(whichfork));
-               if (error)
-                       goto out;
-       } else {
-               irecs->br_startblock = XFS_DADDR_TO_FSB(mp, mappedbno);
-               irecs->br_startoff = (xfs_fileoff_t)bno;
-               irecs->br_blockcount = nfsb;
-               irecs->br_state = 0;
-               nirecs = 1;
-       }
+       if (nfsb != 1)
+               irecs = kmem_zalloc(sizeof(irec) * nfsb, KM_NOFS);
+       nirecs = nfsb;
+       error = xfs_bmapi_read(dp, (xfs_fileoff_t)bno, nfsb, irecs,
+                              &nirecs, xfs_bmapi_aflag(whichfork));
+       if (error)
+               goto out;
 
        if (!xfs_da_map_covers_blocks(nirecs, irecs, bno, nfsb)) {
                /* Caller ok with no mapping. */
@@ -2613,24 +2598,29 @@ out:
  */
 int
 xfs_da_get_buf(
-       struct xfs_trans        *trans,
+       struct xfs_trans        *tp,
        struct xfs_inode        *dp,
        xfs_dablk_t             bno,
        xfs_daddr_t             mappedbno,
        struct xfs_buf          **bpp,
        int                     whichfork)
 {
+       struct xfs_mount        *mp = dp->i_mount;
        struct xfs_buf          *bp;
-       struct xfs_buf_map      map;
-       struct xfs_buf_map      *mapp;
-       int                     nmap;
+       struct xfs_buf_map      map, *mapp = ↦
+       int                     nmap = 1;
        int                     error;
 
        *bpp = NULL;
-       mapp = ↦
-       nmap = 1;
-       error = xfs_dabuf_map(dp, bno, mappedbno, whichfork,
-                               &mapp, &nmap);
+
+       if (mappedbno >= 0) {
+               bp = xfs_trans_get_buf(tp, mp->m_ddev_targp, mappedbno,
+                               XFS_FSB_TO_BB(mp,
+                                       xfs_dabuf_nfsb(mp, whichfork)), 0);
+               goto done;
+       }
+
+       error = xfs_dabuf_map(dp, bno, mappedbno, whichfork, &mapp, &nmap);
        if (error) {
                /* mapping a hole is not an error, but we don't continue */
                if (error == -1)
@@ -2638,12 +2628,12 @@ xfs_da_get_buf(
                goto out_free;
        }
 
-       bp = xfs_trans_get_buf_map(trans, dp->i_mount->m_ddev_targp,
-                                   mapp, nmap, 0);
+       bp = xfs_trans_get_buf_map(tp, mp->m_ddev_targp, mapp, nmap, 0);
+done:
        error = bp ? bp->b_error : -EIO;
        if (error) {
                if (bp)
-                       xfs_trans_brelse(trans, bp);
+                       xfs_trans_brelse(tp, bp);
                goto out_free;
        }
 
@@ -2661,7 +2651,7 @@ out_free:
  */
 int
 xfs_da_read_buf(
-       struct xfs_trans        *trans,
+       struct xfs_trans        *tp,
        struct xfs_inode        *dp,
        xfs_dablk_t             bno,
        xfs_daddr_t             mappedbno,
@@ -2669,17 +2659,23 @@ xfs_da_read_buf(
        int                     whichfork,
        const struct xfs_buf_ops *ops)
 {
+       struct xfs_mount        *mp = dp->i_mount;
        struct xfs_buf          *bp;
-       struct xfs_buf_map      map;
-       struct xfs_buf_map      *mapp;
-       int                     nmap;
+       struct xfs_buf_map      map, *mapp = ↦
+       int                     nmap = 1;
        int                     error;
 
        *bpp = NULL;
-       mapp = ↦
-       nmap = 1;
-       error = xfs_dabuf_map(dp, bno, mappedbno, whichfork,
-                               &mapp, &nmap);
+
+       if (mappedbno >= 0) {
+               error = xfs_trans_read_buf(mp, tp, mp->m_ddev_targp,
+                               mappedbno, XFS_FSB_TO_BB(mp,
+                                       xfs_dabuf_nfsb(mp, whichfork)),
+                               0, &bp, ops);
+               goto done;
+       }
+
+       error = xfs_dabuf_map(dp, bno, mappedbno, whichfork, &mapp, &nmap);
        if (error) {
                /* mapping a hole is not an error, but we don't continue */
                if (error == -1)
@@ -2687,9 +2683,9 @@ xfs_da_read_buf(
                goto out_free;
        }
 
-       error = xfs_trans_read_buf_map(dp->i_mount, trans,
-                                       dp->i_mount->m_ddev_targp,
-                                       mapp, nmap, 0, &bp, ops);
+       error = xfs_trans_read_buf_map(mp, tp, mp->m_ddev_targp, mapp, nmap, 0,
+                       &bp, ops);
+done:
        if (error)
                goto out_free;
 
@@ -2721,6 +2717,9 @@ xfs_da_reada_buf(
        int                     nmap;
        int                     error;
 
+       if (mappedbno >= 0)
+               return -EINVAL;
+
        mapp = ↦
        nmap = 1;
        error = xfs_dabuf_map(dp, bno, mappedbno, whichfork,