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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>
This commit is contained in:
Christoph Hellwig 2019-11-08 15:05:32 -08:00 committed by Darrick J. Wong
parent 263dde869b
commit 2f4369a862
1 changed files with 17 additions and 19 deletions
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36
fs/xfs/xfs_dir2_readdir.c
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@ -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;