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Merge branch 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs-2.6
* 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs-2.6: vfs: fix race in rcu lookup of pruned dentry Fix cifs_get_root() [ Edited the last commit to get rid of a 'unused variable "seq"' warning due to Al editing the patch. - Linus ]
This commit is contained in:
commit
e501f29c72
@ -35,6 +35,7 @@
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#include <linux/delay.h>
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#include <linux/kthread.h>
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#include <linux/freezer.h>
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#include <linux/namei.h>
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#include <net/ipv6.h>
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#include "cifsfs.h"
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#include "cifspdu.h"
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@ -542,14 +543,12 @@ static const struct super_operations cifs_super_ops = {
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static struct dentry *
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cifs_get_root(struct smb_vol *vol, struct super_block *sb)
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{
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int xid, rc;
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struct inode *inode;
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struct qstr name;
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struct dentry *dparent = NULL, *dchild = NULL, *alias;
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struct dentry *dentry;
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struct cifs_sb_info *cifs_sb = CIFS_SB(sb);
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unsigned int i, full_len, len;
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char *full_path = NULL, *pstart;
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char *full_path = NULL;
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char *s, *p;
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char sep;
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int xid;
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full_path = cifs_build_path_to_root(vol, cifs_sb,
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cifs_sb_master_tcon(cifs_sb));
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@ -560,73 +559,32 @@ cifs_get_root(struct smb_vol *vol, struct super_block *sb)
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xid = GetXid();
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sep = CIFS_DIR_SEP(cifs_sb);
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dparent = dget(sb->s_root);
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full_len = strlen(full_path);
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full_path[full_len] = sep;
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pstart = full_path + 1;
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dentry = dget(sb->s_root);
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p = s = full_path;
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for (i = 1, len = 0; i <= full_len; i++) {
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if (full_path[i] != sep || !len) {
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len++;
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continue;
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}
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do {
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struct inode *dir = dentry->d_inode;
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struct dentry *child;
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full_path[i] = 0;
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cFYI(1, "get dentry for %s", pstart);
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/* skip separators */
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while (*s == sep)
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s++;
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if (!*s)
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break;
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p = s++;
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/* next separator */
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while (*s && *s != sep)
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s++;
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name.name = pstart;
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name.len = len;
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name.hash = full_name_hash(pstart, len);
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dchild = d_lookup(dparent, &name);
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if (dchild == NULL) {
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cFYI(1, "not exists");
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dchild = d_alloc(dparent, &name);
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if (dchild == NULL) {
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dput(dparent);
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dparent = ERR_PTR(-ENOMEM);
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goto out;
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}
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}
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cFYI(1, "get inode");
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if (dchild->d_inode == NULL) {
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cFYI(1, "not exists");
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inode = NULL;
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if (cifs_sb_master_tcon(CIFS_SB(sb))->unix_ext)
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rc = cifs_get_inode_info_unix(&inode, full_path,
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sb, xid);
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else
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rc = cifs_get_inode_info(&inode, full_path,
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NULL, sb, xid, NULL);
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if (rc) {
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dput(dchild);
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dput(dparent);
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dparent = ERR_PTR(rc);
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goto out;
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}
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alias = d_materialise_unique(dchild, inode);
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if (alias != NULL) {
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dput(dchild);
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if (IS_ERR(alias)) {
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dput(dparent);
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dparent = ERR_PTR(-EINVAL); /* XXX */
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goto out;
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}
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dchild = alias;
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}
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}
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cFYI(1, "parent %p, child %p", dparent, dchild);
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dput(dparent);
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dparent = dchild;
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len = 0;
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pstart = full_path + i + 1;
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full_path[i] = sep;
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}
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out:
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mutex_lock(&dir->i_mutex);
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child = lookup_one_len(p, dentry, s - p);
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mutex_unlock(&dir->i_mutex);
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dput(dentry);
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dentry = child;
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} while (!IS_ERR(dentry));
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_FreeXid(xid);
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kfree(full_path);
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return dparent;
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return dentry;
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}
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static int cifs_set_super(struct super_block *sb, void *data)
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@ -942,7 +942,6 @@ static bool __follow_mount_rcu(struct nameidata *nd, struct path *path,
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* Don't forget we might have a non-mountpoint managed dentry
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* that wants to block transit.
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*/
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*inode = path->dentry->d_inode;
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if (unlikely(managed_dentry_might_block(path->dentry)))
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return false;
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@ -955,6 +954,12 @@ static bool __follow_mount_rcu(struct nameidata *nd, struct path *path,
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path->mnt = mounted;
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path->dentry = mounted->mnt_root;
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nd->seq = read_seqcount_begin(&path->dentry->d_seq);
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/*
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* Update the inode too. We don't need to re-check the
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* dentry sequence number here after this d_inode read,
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* because a mount-point is always pinned.
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*/
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*inode = path->dentry->d_inode;
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}
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return true;
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}
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