[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, 7 insertions, 5 deletions

diff --git a/fs/xfs/xfs_dir2.c b/fs/xfs/xfs_dir2.c
index 0284af1734bd..675899bb7048 100644
--- a/fs/xfs/xfs_dir2.c
+++ b/fs/xfs/xfs_dir2.c
@@ -65,6 +65,7 @@ xfs_dir_mount(
                 (mp->m_dirblksize - (uint)sizeof(xfs_da_node_hdr_t)) /
                 (uint)sizeof(xfs_da_node_entry_t);
         mp->m_dir_magicpct = (mp->m_dirblksize * 37) / 100;
+        mp->m_dirnameops = &xfs_default_nameops;
 }
 
 /*
@@ -164,7 +165,7 @@ xfs_dir_createname(
 
         args.name = name->name;
         args.namelen = name->len;
-        args.hashval = xfs_da_hashname(name->name, name->len);
+        args.hashval = dp->i_mount->m_dirnameops->hashname(name);
         args.inumber = inum;
         args.dp = dp;
         args.firstblock = first;
@@ -210,11 +211,12 @@ xfs_dir_lookup(
 
         args.name = name->name;
         args.namelen = name->len;
-        args.hashval = xfs_da_hashname(name->name, name->len);
+        args.hashval = dp->i_mount->m_dirnameops->hashname(name);
         args.dp = dp;
         args.whichfork = XFS_DATA_FORK;
         args.trans = tp;
         args.oknoent = 1;
+        args.cmpresult = XFS_CMP_DIFFERENT;
 
         if (dp->i_d.di_format == XFS_DINODE_FMT_LOCAL)
                 rval = xfs_dir2_sf_lookup(&args);
@@ -257,7 +259,7 @@ xfs_dir_removename(
 
         args.name = name->name;
         args.namelen = name->len;
-        args.hashval = xfs_da_hashname(name->name, name->len);
+        args.hashval = dp->i_mount->m_dirnameops->hashname(name);
         args.inumber = ino;
         args.dp = dp;
         args.firstblock = first;
@@ -340,7 +342,7 @@ xfs_dir_replace(
 
         args.name = name->name;
         args.namelen = name->len;
-        args.hashval = xfs_da_hashname(name->name, name->len);
+        args.hashval = dp->i_mount->m_dirnameops->hashname(name);
         args.inumber = inum;
         args.dp = dp;
         args.firstblock = first;
@@ -388,7 +390,7 @@ xfs_dir_canenter(
 
         args.name = name->name;
         args.namelen = name->len;
-        args.hashval = xfs_da_hashname(name->name, name->len);
+        args.hashval = dp->i_mount->m_dirnameops->hashname(name);
         args.dp = dp;
         args.whichfork = XFS_DATA_FORK;
         args.trans = tp;