[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_da_btree.c b/fs/xfs/xfs_da_btree.c
index 2947804..ae4b18c 100644
--- a/fs/xfs/xfs_da_btree.c
+++ b/fs/xfs/xfs_da_btree.c
@@ -1530,6 +1530,28 @@
}
}
+enum xfs_dacmp
+xfs_da_compname(
+ struct xfs_da_args *args,
+ const char *name,
+ int len)
+{
+ return (args->namelen == len && memcmp(args->name, name, len) == 0) ?
+ XFS_CMP_EXACT : XFS_CMP_DIFFERENT;
+}
+
+static xfs_dahash_t
+xfs_default_hashname(
+ struct xfs_name *name)
+{
+ return xfs_da_hashname(name->name, name->len);
+}
+
+const struct xfs_nameops xfs_default_nameops = {
+ .hashname = xfs_default_hashname,
+ .compname = xfs_da_compname
+};
+
/*
* Add a block to the btree ahead of the file.
* Return the new block number to the caller.