[PATCH 29/46] xfs: cleanup xfs_dir2_block_getdents

Christoph Hellwig
2019-11-07T18:25:31Z

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>
---
fs/xfs/xfs_dir2_readdir.c | 32 ++++++++++++--------------------
1 file changed, 12 insertions(+), 20 deletions(-)

diff --git a/fs/xfs/xfs_dir2_readdir.c b/fs/xfs/xfs_dir2_readdir.c
index 187bb51875c2..0d234b649d65 100644
--- 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);
--
2.20.1