[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>
diff --git a/fs/xfs/xfs_dir2_node.c b/fs/xfs/xfs_dir2_node.c
index e29b7c6..fedf8f9 100644
--- a/fs/xfs/xfs_dir2_node.c
+++ b/fs/xfs/xfs_dir2_node.c
@@ -556,6 +556,7 @@
xfs_mount_t *mp; /* filesystem mount point */
xfs_dir2_db_t newdb; /* new data block number */
xfs_trans_t *tp; /* transaction pointer */
+ enum xfs_dacmp cmp; /* comparison result */
dp = args->dp;
tp = args->trans;
@@ -620,17 +621,21 @@
dep = (xfs_dir2_data_entry_t *)((char *)curbp->data +
xfs_dir2_dataptr_to_off(mp, be32_to_cpu(lep->address)));
/*
- * Compare the entry, return it if it matches.
+ * Compare the entry and if it's an exact match, return
+ * EEXIST immediately. If it's the first case-insensitive
+ * match, store the inode number and continue looking.
*/
- if (dep->namelen == args->namelen && memcmp(dep->name,
- args->name, args->namelen) == 0) {
+ cmp = mp->m_dirnameops->compname(args, dep->name, dep->namelen);
+ if (cmp != XFS_CMP_DIFFERENT && cmp != args->cmpresult) {
+ args->cmpresult = cmp;
args->inumber = be64_to_cpu(dep->inumber);
di = (int)((char *)dep - (char *)curbp->data);
error = EEXIST;
- goto out;
+ if (cmp == XFS_CMP_EXACT)
+ goto out;
}
}
- /* Didn't find a match. */
+ /* Didn't find an exact match. */
error = ENOENT;
di = -1;
ASSERT(index == be16_to_cpu(leaf->hdr.count) || args->oknoent);
@@ -1813,6 +1818,8 @@
error = xfs_da_node_lookup_int(state, &rval);
if (error)
rval = error;
+ else if (rval == ENOENT && args->cmpresult == XFS_CMP_CASE)
+ rval = EEXIST; /* a case-insensitive match was found */
/*
* Release the btree blocks and leaf block.
*/
@@ -1856,9 +1863,8 @@
* Look up the entry we're deleting, set up the cursor.
*/
error = xfs_da_node_lookup_int(state, &rval);
- if (error) {
+ if (error)
rval = error;
- }
/*
* Didn't find it, upper layer screwed up.
*/
@@ -1875,9 +1881,8 @@
*/
error = xfs_dir2_leafn_remove(args, blk->bp, blk->index,
&state->extrablk, &rval);
- if (error) {
+ if (error)
return error;
- }
/*
* Fix the hash values up the btree.
*/