[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>

1 files changed, 4 insertions, 1 deletions

diff --git a/fs/xfs/xfs_dir2_data.c b/fs/xfs/xfs_dir2_data.c
index fb8c9e08b23d..498f8d694330 100644
--- a/fs/xfs/xfs_dir2_data.c
+++ b/fs/xfs/xfs_dir2_data.c
@@ -65,6 +65,7 @@ xfs_dir2_data_check(
         xfs_mount_t             *mp;            /* filesystem mount point */
         char                    *p;             /* current data position */
         int                     stale;          /* count of stale leaves */
+        struct xfs_name         name;
 
         mp = dp->i_mount;
         d = bp->data;
@@ -140,7 +141,9 @@ xfs_dir2_data_check(
                         addr = xfs_dir2_db_off_to_dataptr(mp, mp->m_dirdatablk,
                                 (xfs_dir2_data_aoff_t)
                                 ((char *)dep - (char *)d));
-                        hash = xfs_da_hashname((char *)dep->name, dep->namelen);
+                        name.name = dep->name;
+                        name.len = dep->namelen;
+                        hash = mp->m_dirnameops->hashname(&name);
                         for (i = 0; i < be32_to_cpu(btp->count); i++) {
                                 if (be32_to_cpu(lep[i].address) == addr &&
                                     be32_to_cpu(lep[i].hashval) == hash)