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xfs: cleanup xfs_dir2_block_getdents

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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>
This commit is contained in:
Christoph Hellwig 2019-11-08 15:05:32 -08:00 committed by Darrick J. Wong
parent ee641d5af5
commit 263dde869b
1 changed files with 12 additions and 20 deletions

32
fs/xfs/xfs_dir2_readdir.c
View File

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