On Mon, 18 Jul 2011 18:34:54 +0100
Al Viro <viro@xxxxxxxxxxxxxxxxxx> wrote:
> On Mon, Jul 18, 2011 at 05:45:02PM +0100, Al Viro wrote:
> > lookup-by-hand code in there. Or with calculating hash - also done
> > by lookup_one_len(), TYVM... If anything, I'd start with this as the first
> > approximation and probably looked into simplifying the loop a bit more -
> > lookup_one_len() doesn't need name component to be NUL-terminated...
>
> Fix cifs_get_root()
>
> Add missing ->i_mutex, convert to lookup_one_len() instead of
> (broken) open-coded analog, cope with getting something like
> a//b as relative pathname. Simplify the hell out of it, while
> we are there...
>
> Signed-off-by: Al Viro <viro@xxxxxxxxxxxxxxxxxx>
> ---
> diff --git a/fs/cifs/cifsfs.c b/fs/cifs/cifsfs.c
> index 112fbd96..cbbb55e 100644
> --- a/fs/cifs/cifsfs.c
> +++ b/fs/cifs/cifsfs.c
> @@ -35,6 +35,7 @@
> #include <linux/delay.h>
> #include <linux/kthread.h>
> #include <linux/freezer.h>
> +#include <linux/namei.h>
> #include <net/ipv6.h>
> #include "cifsfs.h"
> #include "cifspdu.h"
> @@ -542,14 +543,12 @@ static const struct super_operations cifs_super_ops = {
> static struct dentry *
> cifs_get_root(struct smb_vol *vol, struct super_block *sb)
> {
> - int xid, rc;
> - struct inode *inode;
> - struct qstr name;
> - struct dentry *dparent = NULL, *dchild = NULL, *alias;
> + struct dentry *dentry;
> struct cifs_sb_info *cifs_sb = CIFS_SB(sb);
> - unsigned int i, full_len, len;
> - char *full_path = NULL, *pstart;
> + char *full_path = NULL;
> + char *s, *p;
> char sep;
> + int xid;
>
> full_path = cifs_build_path_to_root(vol, cifs_sb,
> cifs_sb_master_tcon(cifs_sb));
> @@ -560,73 +559,32 @@ cifs_get_root(struct smb_vol *vol, struct super_block *sb)
>
> xid = GetXid();
> sep = CIFS_DIR_SEP(cifs_sb);
> - dparent = dget(sb->s_root);
> - full_len = strlen(full_path);
> - full_path[full_len] = sep;
> - pstart = full_path + 1;
> -
> - for (i = 1, len = 0; i <= full_len; i++) {
> - if (full_path[i] != sep || !len) {
> - len++;
> - continue;
> - }
> -
> - full_path[i] = 0;
> - cFYI(1, "get dentry for %s", pstart);
> -
> - name.name = pstart;
> - name.len = len;
> - name.hash = full_name_hash(pstart, len);
> - dchild = d_lookup(dparent, &name);
> - if (dchild == NULL) {
> - cFYI(1, "not exists");
> - dchild = d_alloc(dparent, &name);
> - if (dchild == NULL) {
> - dput(dparent);
> - dparent = ERR_PTR(-ENOMEM);
> - goto out;
> - }
> - }
> -
> - cFYI(1, "get inode");
> - if (dchild->d_inode == NULL) {
> - cFYI(1, "not exists");
> - inode = NULL;
> - if (cifs_sb_master_tcon(CIFS_SB(sb))->unix_ext)
> - rc = cifs_get_inode_info_unix(&inode, full_path,
> - sb, xid);
> - else
> - rc = cifs_get_inode_info(&inode, full_path,
> - NULL, sb, xid, NULL);
> - if (rc) {
> - dput(dchild);
> - dput(dparent);
> - dparent = ERR_PTR(rc);
> - goto out;
> - }
> - alias = d_materialise_unique(dchild, inode);
> - if (alias != NULL) {
> - dput(dchild);
> - if (IS_ERR(alias)) {
> - dput(dparent);
> - dparent = ERR_PTR(-EINVAL); /* XXX */
> - goto out;
> - }
> - dchild = alias;
> - }
> - }
> - cFYI(1, "parent %p, child %p", dparent, dchild);
> -
> - dput(dparent);
> - dparent = dchild;
> - len = 0;
> - pstart = full_path + i + 1;
> - full_path[i] = sep;
> - }
> -out:
> + dentry = dget(sb->s_root);
> + p = s = full_path;
> +
> + do {
> + struct inode *dir = dentry->d_inode;
> + struct dentry *child;
> +
> + /* skip separators */
> + while (*s == sep)
> + s++;
> + if (!*s)
> + break;
> + p = s++;
> + /* next separator */
> + while (*s && *s != sep)
> + s++;
> +
> + mutex_lock(&dir->i_mutex);
> + child = lookup_one_len(p, dentry, s - p);
> + mutex_unlock(&dir->i_mutex);
> + dput(dentry);
> + dentry = child;
> + } while (!IS_ERR(dentry));
> _FreeXid(xid);
> kfree(full_path);
> - return dparent;
> + return dentry;
> }
>
> static int cifs_set_super(struct super_block *sb, void *data)
Thanks, Al...
Looks good to me. I also gave it some basic smoke testing and it seems
to do the right thing.
Reviewed-by: Jeff Layton <jlayton@xxxxxxxxxx>
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