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authorBarry Naujok <bnaujok@sgi.com>2008-05-21 16:41:01 +1000
committerNiv Sardi <xaiki@debian.org>2008-07-28 16:58:36 +1000
commit5163f95a08cbf058ae16452c2242c5600fedc32e (patch)
tree5d6b905f7031144a62fb1fa17ba3106d99268003 /fs/xfs/xfs_dir2_leaf.c
parent68f34d5107dbace3d14a1c2f060fc8941894879c (diff)
[XFS] Name operation vector for hash and compare
Adds two pieces of functionality for the basis of case-insensitive support in XFS: 1. A comparison result enumerated type: xfs_dacmp. It represents an exact match, case-insensitive match or no match at all. This patch only implements different and exact results. 2. xfs_nameops vector for specifying how to perform the hash generation of filenames and comparision methods. In this patch the hash vector points to the existing xfs_da_hashname function and the comparison method does a length compare, and if the same, does a memcmp and return the xfs_dacmp result. All filename functions that use the hash (create, lookup remove, rename, etc) now use the xfs_nameops.hashname function and all directory lookup functions also use the xfs_nameops.compname function. The lookup functions also handle case-insensitive results even though the default comparison function cannot return that. And important aspect of the lookup functions is that an exact match always has precedence over a case-insensitive. So while a case-insensitive match is found, we have to keep looking just in case there is an exact match. In the meantime, the info for the first case-insensitive match is retained if no exact match is found. SGI-PV: 981519 SGI-Modid: xfs-linux-melb:xfs-kern:31205a Signed-off-by: Barry Naujok <bnaujok@sgi.com> Signed-off-by: Christoph Hellwig <hch@infradead.org>
Diffstat (limited to 'fs/xfs/xfs_dir2_leaf.c')
-rw-r--r--fs/xfs/xfs_dir2_leaf.c60
1 files changed, 43 insertions, 17 deletions
diff --git a/fs/xfs/xfs_dir2_leaf.c b/fs/xfs/xfs_dir2_leaf.c
index e33433408e4..b52903bc0b1 100644
--- a/fs/xfs/xfs_dir2_leaf.c
+++ b/fs/xfs/xfs_dir2_leaf.c
@@ -1331,6 +1331,8 @@ xfs_dir2_leaf_lookup_int(
xfs_mount_t *mp; /* filesystem mount point */
xfs_dir2_db_t newdb; /* new data block number */
xfs_trans_t *tp; /* transaction pointer */
+ xfs_dabuf_t *cbp; /* case match data buffer */
+ enum xfs_dacmp cmp; /* name compare result */
dp = args->dp;
tp = args->trans;
@@ -1354,9 +1356,11 @@ xfs_dir2_leaf_lookup_int(
* Loop over all the entries with the right hash value
* looking to match the name.
*/
+ cbp = NULL;
for (lep = &leaf->ents[index], dbp = NULL, curdb = -1;
- index < be16_to_cpu(leaf->hdr.count) && be32_to_cpu(lep->hashval) == args->hashval;
- lep++, index++) {
+ index < be16_to_cpu(leaf->hdr.count) &&
+ be32_to_cpu(lep->hashval) == args->hashval;
+ lep++, index++) {
/*
* Skip over stale leaf entries.
*/
@@ -1371,12 +1375,12 @@ xfs_dir2_leaf_lookup_int(
* need to pitch the old one and read the new one.
*/
if (newdb != curdb) {
- if (dbp)
+ if (dbp != cbp)
xfs_da_brelse(tp, dbp);
- if ((error =
- xfs_da_read_buf(tp, dp,
- xfs_dir2_db_to_da(mp, newdb), -1, &dbp,
- XFS_DATA_FORK))) {
+ error = xfs_da_read_buf(tp, dp,
+ xfs_dir2_db_to_da(mp, newdb),
+ -1, &dbp, XFS_DATA_FORK);
+ if (error) {
xfs_da_brelse(tp, lbp);
return error;
}
@@ -1386,24 +1390,46 @@ xfs_dir2_leaf_lookup_int(
/*
* Point to the data entry.
*/
- dep = (xfs_dir2_data_entry_t *)
- ((char *)dbp->data +
- xfs_dir2_dataptr_to_off(mp, be32_to_cpu(lep->address)));
+ dep = (xfs_dir2_data_entry_t *)((char *)dbp->data +
+ xfs_dir2_dataptr_to_off(mp, be32_to_cpu(lep->address)));
/*
- * If it matches then return it.
+ * Compare name and if it's an exact match, return the index
+ * and buffer. If it's the first case-insensitive match, store
+ * the index and buffer and continue looking for an exact match.
*/
- if (dep->namelen == args->namelen &&
- dep->name[0] == args->name[0] &&
- memcmp(dep->name, args->name, args->namelen) == 0) {
- *dbpp = dbp;
+ cmp = mp->m_dirnameops->compname(args, dep->name, dep->namelen);
+ if (cmp != XFS_CMP_DIFFERENT && cmp != args->cmpresult) {
+ args->cmpresult = cmp;
*indexp = index;
- return 0;
+ /*
+ * case exact match: release the stored CI buffer if it
+ * exists and return the current buffer.
+ */
+ if (cmp == XFS_CMP_EXACT) {
+ if (cbp && cbp != dbp)
+ xfs_da_brelse(tp, cbp);
+ *dbpp = dbp;
+ return 0;
+ }
+ cbp = dbp;
}
}
+ ASSERT(args->oknoent);
+ /*
+ * Here, we can only be doing a lookup (not a rename or replace).
+ * If a case-insensitive match was found earlier, release the current
+ * buffer and return the stored CI matching buffer.
+ */
+ if (args->cmpresult == XFS_CMP_CASE) {
+ if (cbp != dbp)
+ xfs_da_brelse(tp, dbp);
+ *dbpp = cbp;
+ return 0;
+ }
/*
* No match found, return ENOENT.
*/
- ASSERT(args->oknoent);
+ ASSERT(cbp == NULL);
if (dbp)
xfs_da_brelse(tp, dbp);
xfs_da_brelse(tp, lbp);