[XFS] XFS: ASCII case-insensitive support
Implement ASCII case-insensitive support. It's primary purpose is for
supporting existing filesystems that already use this case-insensitive
mode migrated from IRIX. But, if you only need ASCII-only case-insensitive
support (ie. English only) and will never use another language, then this
mode is perfectly adequate.
ASCII-CI is implemented by generating hashes based on lower-case letters
and doing lower-case compares. It implements a new xfs_nameops vector for
doing the hashes and comparisons for all filename operations.
To create a filesystem with this CI mode, use: # mkfs.xfs -n version=ci
<device>
SGI-PV: 981516
SGI-Modid: xfs-linux-melb:xfs-kern:31209a
Signed-off-by: Barry Naujok <bnaujok@sgi.com>
Signed-off-by: Christoph Hellwig <hch@infradead.org>
diff --git a/fs/xfs/xfs_dir2.c b/fs/xfs/xfs_dir2.c
index 882609c..b445ec3 100644
--- a/fs/xfs/xfs_dir2.c
+++ b/fs/xfs/xfs_dir2.c
@@ -48,6 +48,52 @@
extern const struct xfs_nameops xfs_default_nameops;
+/*
+ * ASCII case-insensitive (ie. A-Z) support for directories that was
+ * used in IRIX.
+ */
+STATIC xfs_dahash_t
+xfs_ascii_ci_hashname(
+ struct xfs_name *name)
+{
+ xfs_dahash_t hash;
+ int i;
+
+ for (i = 0, hash = 0; i < name->len; i++)
+ hash = tolower(name->name[i]) ^ rol32(hash, 7);
+
+ return hash;
+}
+
+STATIC enum xfs_dacmp
+xfs_ascii_ci_compname(
+ struct xfs_da_args *args,
+ const char *name,
+ int len)
+{
+ enum xfs_dacmp result;
+ int i;
+
+ if (args->namelen != len)
+ return XFS_CMP_DIFFERENT;
+
+ result = XFS_CMP_EXACT;
+ for (i = 0; i < len; i++) {
+ if (args->name[i] == name[i])
+ continue;
+ if (tolower(args->name[i]) != tolower(name[i]))
+ return XFS_CMP_DIFFERENT;
+ result = XFS_CMP_CASE;
+ }
+
+ return result;
+}
+
+static struct xfs_nameops xfs_ascii_ci_nameops = {
+ .hashname = xfs_ascii_ci_hashname,
+ .compname = xfs_ascii_ci_compname,
+};
+
void
xfs_dir_mount(
xfs_mount_t *mp)
@@ -67,7 +113,10 @@
(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;
+ if (xfs_sb_version_hasasciici(&mp->m_sb))
+ mp->m_dirnameops = &xfs_ascii_ci_nameops;
+ else
+ mp->m_dirnameops = &xfs_default_nameops;
}
/*