[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_block.c b/fs/xfs/xfs_dir2_block.c
index e8a7aca..9858849 100644
--- a/fs/xfs/xfs_dir2_block.c
+++ b/fs/xfs/xfs_dir2_block.c
@@ -643,6 +643,7 @@
int mid; /* binary search current idx */
xfs_mount_t *mp; /* filesystem mount point */
xfs_trans_t *tp; /* transaction pointer */
+ enum xfs_dacmp cmp; /* comparison result */
dp = args->dp;
tp = args->trans;
@@ -697,20 +698,31 @@
dep = (xfs_dir2_data_entry_t *)
((char *)block + xfs_dir2_dataptr_to_off(mp, addr));
/*
- * Compare, if it's right give back buffer & entry number.
+ * 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) {
+ cmp = mp->m_dirnameops->compname(args, dep->name, dep->namelen);
+ if (cmp != XFS_CMP_DIFFERENT && cmp != args->cmpresult) {
+ args->cmpresult = cmp;
*bpp = bp;
*entno = mid;
- return 0;
+ if (cmp == XFS_CMP_EXACT)
+ return 0;
}
- } while (++mid < be32_to_cpu(btp->count) && be32_to_cpu(blp[mid].hashval) == hash);
+ } while (++mid < be32_to_cpu(btp->count) &&
+ be32_to_cpu(blp[mid].hashval) == hash);
+
+ ASSERT(args->oknoent);
+ /*
+ * Here, we can only be doing a lookup (not a rename or replace).
+ * If a case-insensitive match was found earlier, return success.
+ */
+ if (args->cmpresult == XFS_CMP_CASE)
+ return 0;
/*
* No match, release the buffer and return ENOENT.
*/
- ASSERT(args->oknoent);
xfs_da_brelse(tp, bp);
return XFS_ERROR(ENOENT);
}
@@ -1033,6 +1045,7 @@
xfs_dir2_sf_t *sfp; /* shortform structure */
__be16 *tagp; /* end of data entry */
xfs_trans_t *tp; /* transaction pointer */
+ struct xfs_name name;
xfs_dir2_trace_args("sf_to_block", args);
dp = args->dp;
@@ -1187,8 +1200,10 @@
tagp = xfs_dir2_data_entry_tag_p(dep);
*tagp = cpu_to_be16((char *)dep - (char *)block);
xfs_dir2_data_log_entry(tp, bp, dep);
- blp[2 + i].hashval = cpu_to_be32(xfs_da_hashname(
- (char *)sfep->name, sfep->namelen));
+ name.name = sfep->name;
+ name.len = sfep->namelen;
+ blp[2 + i].hashval = cpu_to_be32(mp->m_dirnameops->
+ hashname(&name));
blp[2 + i].address = cpu_to_be32(xfs_dir2_byte_to_dataptr(mp,
(char *)dep - (char *)block));
offset = (int)((char *)(tagp + 1) - (char *)block);