xfs: refactor xfs_dabuf_map

Merge xfs_buf_map_from_irec and xfs_da_map_covers_blocks into a single
loop in the caller.

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>

diff --git a/fs/xfs/libxfs/xfs_da_btree.c b/fs/xfs/libxfs/xfs_da_btree.c
index f3087f061a4886b613220ed528a9516c22d87392..e078817fc26ca00f50d919a9027394fedc7d5d0c 100644 (file)
--- a/fs/xfs/libxfs/xfs_da_btree.c
+++ b/fs/xfs/libxfs/xfs_da_btree.c
@@ -2460,74 +2460,6 @@ xfs_da_shrink_inode(
        return error;
 }
 
-/*
- * See if the mapping(s) for this btree block are valid, i.e.
- * don't contain holes, are logically contiguous, and cover the whole range.
- */
-STATIC int
-xfs_da_map_covers_blocks(
-       int             nmap,
-       xfs_bmbt_irec_t *mapp,
-       xfs_dablk_t     bno,
-       int             count)
-{
-       int             i;
-       xfs_fileoff_t   off;
-
-       for (i = 0, off = bno; i < nmap; i++) {
-               if (mapp[i].br_startblock == HOLESTARTBLOCK ||
-                   mapp[i].br_startblock == DELAYSTARTBLOCK) {
-                       return 0;
-               }
-               if (off != mapp[i].br_startoff) {
-                       return 0;
-               }
-               off += mapp[i].br_blockcount;
-       }
-       return off == bno + count;
-}
-
-/*
- * Convert a struct xfs_bmbt_irec to a struct xfs_buf_map.
- *
- * For the single map case, it is assumed that the caller has provided a pointer
- * to a valid xfs_buf_map.  For the multiple map case, this function will
- * allocate the xfs_buf_map to hold all the maps and replace the caller's single
- * map pointer with the allocated map.
- */
-static int
-xfs_buf_map_from_irec(
-       struct xfs_mount        *mp,
-       struct xfs_buf_map      **mapp,
-       int                     *nmaps,
-       struct xfs_bmbt_irec    *irecs,
-       int                     nirecs)
-{
-       struct xfs_buf_map      *map;
-       int                     i;
-
-       ASSERT(*nmaps == 1);
-       ASSERT(nirecs >= 1);
-
-       if (nirecs > 1) {
-               map = kmem_zalloc(nirecs * sizeof(struct xfs_buf_map),
-                                 KM_NOFS);
-               if (!map)
-                       return -ENOMEM;
-               *mapp = map;
-       }
-
-       *nmaps = nirecs;
-       map = *mapp;
-       for (i = 0; i < *nmaps; i++) {
-               ASSERT(irecs[i].br_startblock != DELAYSTARTBLOCK &&
-                      irecs[i].br_startblock != HOLESTARTBLOCK);
-               map[i].bm_bn = XFS_FSB_TO_DADDR(mp, irecs[i].br_startblock);
-               map[i].bm_len = XFS_FSB_TO_BB(mp, irecs[i].br_blockcount);
-       }
-       return 0;
-}
-
 /*
  * Map the block we are given ready for reading. There are three possible return
  * values:
@@ -2542,58 +2474,78 @@ xfs_dabuf_map(
        xfs_dablk_t             bno,
        xfs_daddr_t             mappedbno,
        int                     whichfork,
-       struct xfs_buf_map      **map,
+       struct xfs_buf_map      **mapp,
        int                     *nmaps)
 {
        struct xfs_mount        *mp = dp->i_mount;
        int                     nfsb = xfs_dabuf_nfsb(mp, whichfork);
-       int                     error = 0;
-       struct xfs_bmbt_irec    irec;
-       struct xfs_bmbt_irec    *irecs = &irec;
-       int                     nirecs;
-
-       ASSERT(map && *map);
-       ASSERT(*nmaps == 1);
+       struct xfs_bmbt_irec    irec, *irecs = &irec;
+       struct xfs_buf_map      *map = *mapp;
+       xfs_fileoff_t           off = bno;
+       int                     error = 0, nirecs, i;
 
-       if (nfsb != 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));
+       error = xfs_bmapi_read(dp, bno, nfsb, irecs, &nirecs,
+                       xfs_bmapi_aflag(whichfork));
        if (error)
-               goto out;
+               goto out_free_irecs;
 
-       if (!xfs_da_map_covers_blocks(nirecs, irecs, bno, nfsb)) {
-               /* Caller ok with no mapping. */
-               if (!XFS_IS_CORRUPT(mp, mappedbno != -2)) {
-                       error = -1;
-                       goto out;
-               }
+       /*
+        * Use the caller provided map for the single map case, else allocate a
+        * larger one that needs to be free by the caller.
+        */
+       if (nirecs > 1) {
+               map = kmem_zalloc(nirecs * sizeof(struct xfs_buf_map), KM_NOFS);
+               if (!map)
+                       goto out_free_irecs;
+               *mapp = map;
+       }
 
-               /* Caller expected a mapping, so abort. */
+       for (i = 0; i < nirecs; i++) {
+               if (irecs[i].br_startblock == HOLESTARTBLOCK ||
+                   irecs[i].br_startblock == DELAYSTARTBLOCK)
+                       goto invalid_mapping;
+               if (off != irecs[i].br_startoff)
+                       goto invalid_mapping;
+
+               map[i].bm_bn = XFS_FSB_TO_DADDR(mp, irecs[i].br_startblock);
+               map[i].bm_len = XFS_FSB_TO_BB(mp, irecs[i].br_blockcount);
+               off += irecs[i].br_blockcount;
+       }
+
+       if (off != bno + nfsb)
+               goto invalid_mapping;
+
+       *nmaps = nirecs;
+out_free_irecs:
+       if (irecs != &irec)
+               kmem_free(irecs);
+       return error;
+
+invalid_mapping:
+       /* Caller ok with no mapping. */
+       if (XFS_IS_CORRUPT(mp, mappedbno != -2)) {
+               error = -EFSCORRUPTED;
                if (xfs_error_level >= XFS_ERRLEVEL_LOW) {
-                       int i;
+                       xfs_alert(mp, "%s: bno %u inode %llu",
+                                       __func__, bno, dp->i_ino);
 
-                       xfs_alert(mp, "%s: bno %lld dir: inode %lld", __func__,
-                                       (long long)bno, (long long)dp->i_ino);
-                       for (i = 0; i < *nmaps; i++) {
+                       for (i = 0; i < nirecs; i++) {
                                xfs_alert(mp,
 "[%02d] br_startoff %lld br_startblock %lld br_blockcount %lld br_state %d",
-                                       i,
-                                       (long long)irecs[i].br_startoff,
-                                       (long long)irecs[i].br_startblock,
-                                       (long long)irecs[i].br_blockcount,
+                                       i, irecs[i].br_startoff,
+                                       irecs[i].br_startblock,
+                                       irecs[i].br_blockcount,
                                        irecs[i].br_state);
                        }
                }
-               error = -EFSCORRUPTED;
-               goto out;
+       } else {
+               *nmaps = 0;
        }
-       error = xfs_buf_map_from_irec(mp, map, nmaps, irecs, nirecs);
-out:
-       if (irecs != &irec)
-               kmem_free(irecs);
-       return error;
+       goto out_free_irecs;
 }
 
 /*