[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.h b/fs/xfs/xfs_da_btree.h
index 7facf86..e64c692 100644
--- a/fs/xfs/xfs_da_btree.h
+++ b/fs/xfs/xfs_da_btree.h
@@ -99,6 +99,15 @@
*========================================================================*/
/*
+ * Search comparison results
+ */
+enum xfs_dacmp {
+ XFS_CMP_DIFFERENT, /* names are completely different */
+ XFS_CMP_EXACT, /* names are exactly the same */
+ XFS_CMP_CASE /* names are same but differ in case */
+};
+
+/*
* Structure to ease passing around component names.
*/
typedef struct xfs_da_args {
@@ -127,6 +136,7 @@
unsigned char rename; /* T/F: this is an atomic rename op */
unsigned char addname; /* T/F: this is an add operation */
unsigned char oknoent; /* T/F: ok to return ENOENT, else die */
+ enum xfs_dacmp cmpresult; /* name compare result for lookups */
} xfs_da_args_t;
/*
@@ -201,6 +211,14 @@
(uint)(XFS_DA_LOGOFF(BASE, ADDR)), \
(uint)(XFS_DA_LOGOFF(BASE, ADDR)+(SIZE)-1)
+/*
+ * Name ops for directory and/or attr name operations
+ */
+struct xfs_nameops {
+ xfs_dahash_t (*hashname)(struct xfs_name *);
+ enum xfs_dacmp (*compname)(struct xfs_da_args *, const char *, int);
+};
+
#ifdef __KERNEL__
/*========================================================================
@@ -249,6 +267,10 @@
xfs_dabuf_t *dead_buf);
uint xfs_da_hashname(const uchar_t *name_string, int name_length);
+enum xfs_dacmp xfs_da_compname(struct xfs_da_args *args,
+ const char *name, int len);
+
+
xfs_da_state_t *xfs_da_state_alloc(void);
void xfs_da_state_free(xfs_da_state_t *state);