xfs: cleanup xfs_dir2_leaf_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 0d234b649d65b7bcb9251775255858521530e692..4a29921d888039bf8c0be85a4c6b2309a3b25135 100644 (file)
--- a/fs/xfs/xfs_dir2_readdir.c
+++ b/fs/xfs/xfs_dir2_readdir.c
@@ -348,16 +348,15 @@ xfs_dir2_leaf_getdents(
 {
        struct xfs_inode        *dp = args->dp;
        struct xfs_buf          *bp = NULL;     /* data block buffer */
-       xfs_dir2_data_hdr_t     *hdr;           /* data block header */
        xfs_dir2_data_entry_t   *dep;           /* data entry */
        xfs_dir2_data_unused_t  *dup;           /* unused entry */
-       char                    *ptr = NULL;    /* pointer to current data */
        struct xfs_da_geometry  *geo = args->geo;
        xfs_dablk_t             rablk = 0;      /* current readahead block */
        xfs_dir2_off_t          curoff;         /* current overall offset */
        int                     length;         /* temporary length value */
        int                     byteoff;        /* offset in current block */
        int                     lock_mode;
+       unsigned int            offset = 0;
        int                     error = 0;      /* error return value */
 
        /*
@@ -384,7 +383,7 @@ xfs_dir2_leaf_getdents(
                 * If we have no buffer, or we're off the end of the
                 * current buffer, need to get another one.
                 */
-               if (!bp || ptr >= (char *)bp->b_addr + geo->blksize) {
+               if (!bp || offset >= geo->blksize) {
                        if (bp) {
                                xfs_trans_brelse(args->trans, bp);
                                bp = NULL;
@@ -397,12 +396,11 @@ xfs_dir2_leaf_getdents(
                        if (error || !bp)
                                break;
 
-                       hdr = bp->b_addr;
                        xfs_dir3_data_check(dp, bp);
                        /*
                         * Find our position in the block.
                         */
-                       ptr = (char *)dp->d_ops->data_entry_p(hdr);
+                       offset = dp->d_ops->data_entry_offset;
                        byteoff = xfs_dir2_byte_to_off(geo, curoff);
                        /*
                         * Skip past the header.
@@ -413,20 +411,20 @@ xfs_dir2_leaf_getdents(
                         * Skip past entries until we reach our offset.
                         */
                        else {
-                               while ((char *)ptr - (char *)hdr < byteoff) {
-                                       dup = (xfs_dir2_data_unused_t *)ptr;
+                               while (offset < byteoff) {
+                                       dup = bp->b_addr + offset;
 
                                        if (be16_to_cpu(dup->freetag)
                                                  == XFS_DIR2_DATA_FREE_TAG) {
 
                                                length = be16_to_cpu(dup->length);
-                                               ptr += length;
+                                               offset += length;
                                                continue;
                                        }
-                                       dep = (xfs_dir2_data_entry_t *)ptr;
+                                       dep = bp->b_addr + offset;
                                        length =
                                           dp->d_ops->data_entsize(dep->namelen);
-                                       ptr += length;
+                                       offset += length;
                                }
                                /*
                                 * Now set our real offset.
@@ -434,28 +432,28 @@ xfs_dir2_leaf_getdents(
                                curoff =
                                        xfs_dir2_db_off_to_byte(geo,
                                            xfs_dir2_byte_to_db(geo, curoff),
-                                           (char *)ptr - (char *)hdr);
-                               if (ptr >= (char *)hdr + geo->blksize) {
+                                           offset);
+                               if (offset >= geo->blksize)
                                        continue;
-                               }
                        }
                }
+
                /*
-                * We have a pointer to an entry.
-                * Is it a live one?
+                * We have a pointer to an entry.  Is it a live one?
                 */
-               dup = (xfs_dir2_data_unused_t *)ptr;
+               dup = bp->b_addr + offset;
+
                /*
                 * No, it's unused, skip over it.
                 */
                if (be16_to_cpu(dup->freetag) == XFS_DIR2_DATA_FREE_TAG) {
                        length = be16_to_cpu(dup->length);
-                       ptr += length;
+                       offset += length;
                        curoff += length;
                        continue;
                }
 
-               dep = (xfs_dir2_data_entry_t *)ptr;
+               dep = bp->b_addr + offset;
                length = dp->d_ops->data_entsize(dep->namelen);
                filetype = dp->d_ops->data_get_ftype(dep);
 
@@ -474,7 +472,7 @@ xfs_dir2_leaf_getdents(
                /*
                 * Advance to next entry in the block.
                 */
-               ptr += length;
+               offset += length;
                curoff += length;
                /* bufsize may have just been a guess; don't go negative */
                bufsize = bufsize > length ? bufsize - length : 0;