xfs: cleanup xfs_dir2_block_getdents

Use an offset as the main means for iteration, and only do pointer
arithmetics to find the data/unused entries.

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/xfs_dir2_readdir.c b/fs/xfs/xfs_dir2_readdir.c
index 187bb51..0d234b6 100644 (file)
--- a/fs/xfs/xfs_dir2_readdir.c
+++ b/fs/xfs/xfs_dir2_readdir.c
@@ -142,17 +142,14 @@ xfs_dir2_block_getdents(
        struct dir_context      *ctx)
 {
        struct xfs_inode        *dp = args->dp; /* incore directory inode */
-       xfs_dir2_data_hdr_t     *hdr;           /* block header */
        struct xfs_buf          *bp;            /* buffer for block */
-       xfs_dir2_data_entry_t   *dep;           /* block data entry */
-       xfs_dir2_data_unused_t  *dup;           /* block unused entry */
-       char                    *endptr;        /* end of the data entries */
        int                     error;          /* error return value */
-       char                    *ptr;           /* current data entry */
        int                     wantoff;        /* starting block offset */
        xfs_off_t               cook;
        struct xfs_da_geometry  *geo = args->geo;
        int                     lock_mode;
+       unsigned int            offset;
+       unsigned int            end;
 
        /*
         * If the block number in the offset is out of range, we're done.
@@ -171,44 +168,39 @@ xfs_dir2_block_getdents(
         * We'll skip entries before this.
         */
        wantoff = xfs_dir2_dataptr_to_off(geo, ctx->pos);
-       hdr = bp->b_addr;
        xfs_dir3_data_check(dp, bp);
-       /*
-        * Set up values for the loop.
-        */
-       ptr = (char *)dp->d_ops->data_entry_p(hdr);
-       endptr = xfs_dir3_data_endp(geo, hdr);
 
        /*
         * Loop over the data portion of the block.
         * Each object is a real entry (dep) or an unused one (dup).
         */
-       while (ptr < endptr) {
+       offset = dp->d_ops->data_entry_offset;
+       end = xfs_dir3_data_endp(geo, bp->b_addr) - bp->b_addr;
+       while (offset < end) {
+               struct xfs_dir2_data_unused     *dup = bp->b_addr + offset;
+               struct xfs_dir2_data_entry      *dep = bp->b_addr + offset;
                uint8_t filetype;
 
-               dup = (xfs_dir2_data_unused_t *)ptr;
                /*
                 * Unused, skip it.
                 */
                if (be16_to_cpu(dup->freetag) == XFS_DIR2_DATA_FREE_TAG) {
-                       ptr += be16_to_cpu(dup->length);
+                       offset += be16_to_cpu(dup->length);
                        continue;
                }
 
-               dep = (xfs_dir2_data_entry_t *)ptr;
-
                /*
                 * Bump pointer for the next iteration.
                 */
-               ptr += dp->d_ops->data_entsize(dep->namelen);
+               offset += dp->d_ops->data_entsize(dep->namelen);
+
                /*
                 * The entry is before the desired starting point, skip it.
                 */
-               if ((char *)dep - (char *)hdr < wantoff)
+               if (offset < wantoff)
                        continue;
 
-               cook = xfs_dir2_db_off_to_dataptr(geo, geo->datablk,
-                                           (char *)dep - (char *)hdr);
+               cook = xfs_dir2_db_off_to_dataptr(geo, geo->datablk, offset);
 
                ctx->pos = cook & 0x7fffffff;
                filetype = dp->d_ops->data_get_ftype(dep);