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[XFS] Return case-insensitive match for dentry cache

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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>
This commit is contained in:
Barry Naujok
2008-05-21 16:58:22 +10:00
committed by Niv Sardi
parent 9403540c06
commit 384f3ced07
12 changed files with 147 additions and 30 deletions
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57
fs/xfs/linux-2.6/xfs_iops.c
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@@ -382,7 +382,7 @@ xfs_vn_lookup(
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 @@ xfs_vn_lookup(
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 @@ const struct inode_operations xfs_dir_inode_operations = {
.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,