[XFS] Return case-insensitive match for dentry cache
This implements the code to store the actual filename found during a
lookup in the dentry cache and to avoid multiple entries in the dcache
pointing to the same inode.
To avoid polluting the dcache, we implement a new directory inode
operations for lookup. xfs_vn_ci_lookup() stores the correct case name in
the dcache.
The "actual name" is only allocated and returned for a case- insensitive
match and not an actual match.
Another unusual interaction with the dcache is not storing negative
dentries like other filesystems doing a d_add(dentry, NULL) when an ENOENT
is returned. During the VFS lookup, if a dentry returned has no inode,
dput is called and ENOENT is returned. By not doing a d_add, this actually
removes it completely from the dcache to be reused. create/rename have to
be modified to support unhashed dentries being passed in.
SGI-PV: 981521
SGI-Modid: xfs-linux-melb:xfs-kern:31208a
Signed-off-by: Barry Naujok <bnaujok@sgi.com>
Signed-off-by: Christoph Hellwig <hch@infradead.org>
diff --git a/fs/xfs/linux-2.6/xfs_iops.c b/fs/xfs/linux-2.6/xfs_iops.c
index 13b6cfd..9f0f8ee 100644
--- a/fs/xfs/linux-2.6/xfs_iops.c
+++ b/fs/xfs/linux-2.6/xfs_iops.c
@@ -382,7 +382,7 @@
return ERR_PTR(-ENAMETOOLONG);
xfs_dentry_to_name(&name, dentry);
- error = xfs_lookup(XFS_I(dir), &name, &cip);
+ error = xfs_lookup(XFS_I(dir), &name, &cip, NULL);
if (unlikely(error)) {
if (unlikely(error != ENOENT))
return ERR_PTR(-error);
@@ -393,6 +393,42 @@
return d_splice_alias(cip->i_vnode, dentry);
}
+STATIC struct dentry *
+xfs_vn_ci_lookup(
+ struct inode *dir,
+ struct dentry *dentry,
+ struct nameidata *nd)
+{
+ struct xfs_inode *ip;
+ struct xfs_name xname;
+ struct xfs_name ci_name;
+ struct qstr dname;
+ int error;
+
+ if (dentry->d_name.len >= MAXNAMELEN)
+ return ERR_PTR(-ENAMETOOLONG);
+
+ xfs_dentry_to_name(&xname, dentry);
+ error = xfs_lookup(XFS_I(dir), &xname, &ip, &ci_name);
+ if (unlikely(error)) {
+ if (unlikely(error != ENOENT))
+ return ERR_PTR(-error);
+ d_add(dentry, NULL);
+ return NULL;
+ }
+
+ /* if exact match, just splice and exit */
+ if (!ci_name.name)
+ return d_splice_alias(ip->i_vnode, dentry);
+
+ /* else case-insensitive match... */
+ dname.name = ci_name.name;
+ dname.len = ci_name.len;
+ dentry = d_add_ci(ip->i_vnode, dentry, &dname);
+ kmem_free(ci_name.name);
+ return dentry;
+}
+
STATIC int
xfs_vn_link(
struct dentry *old_dentry,
@@ -892,6 +928,25 @@
.removexattr = xfs_vn_removexattr,
};
+const struct inode_operations xfs_dir_ci_inode_operations = {
+ .create = xfs_vn_create,
+ .lookup = xfs_vn_ci_lookup,
+ .link = xfs_vn_link,
+ .unlink = xfs_vn_unlink,
+ .symlink = xfs_vn_symlink,
+ .mkdir = xfs_vn_mkdir,
+ .rmdir = xfs_vn_rmdir,
+ .mknod = xfs_vn_mknod,
+ .rename = xfs_vn_rename,
+ .permission = xfs_vn_permission,
+ .getattr = xfs_vn_getattr,
+ .setattr = xfs_vn_setattr,
+ .setxattr = xfs_vn_setxattr,
+ .getxattr = xfs_vn_getxattr,
+ .listxattr = xfs_vn_listxattr,
+ .removexattr = xfs_vn_removexattr,
+};
+
const struct inode_operations xfs_symlink_inode_operations = {
.readlink = generic_readlink,
.follow_link = xfs_vn_follow_link,