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Commit e501f29c authored by Linus Torvalds's avatar Linus Torvalds
Browse files

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 ]
parents 3a5c3743 59430262

fs/cifs/cifsfs.c

+29 −71
Original line number Original line Diff line number Diff line
@@ -35,6 +35,7 @@ 
#include <linux/delay.h>

#include <linux/delay.h>

#include <linux/kthread.h>

#include <linux/kthread.h>

#include <linux/freezer.h>

#include <linux/freezer.h>

#include <linux/namei.h>

#include <net/ipv6.h>

#include <net/ipv6.h>

#include "cifsfs.h"

#include "cifsfs.h"

#include "cifspdu.h"

#include "cifspdu.h"
@@ -542,14 +543,12 @@ static const struct super_operations cifs_super_ops = { 
static struct dentry *

static struct dentry *

cifs_get_root(struct smb_vol *vol, struct super_block *sb)

cifs_get_root(struct smb_vol *vol, struct super_block *sb)

{

{

	int xid, rc;

	struct dentry *dentry;

	struct inode *inode;

	struct qstr name;

	struct dentry *dparent = NULL, *dchild = NULL, *alias;

	struct cifs_sb_info *cifs_sb = CIFS_SB(sb);

	struct cifs_sb_info *cifs_sb = CIFS_SB(sb);

	unsigned int i, full_len, len;

	char *full_path = NULL;

	char *full_path = NULL, *pstart;

	char *s, *p;

	char sep;

	char sep;

	int xid;





	full_path = cifs_build_path_to_root(vol, cifs_sb,

	full_path = cifs_build_path_to_root(vol, cifs_sb,

					    cifs_sb_master_tcon(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();

	xid = GetXid();

	sep = CIFS_DIR_SEP(cifs_sb);

	sep = CIFS_DIR_SEP(cifs_sb);

	dparent = dget(sb->s_root);

	dentry = dget(sb->s_root);

	full_len = strlen(full_path);

	p = s = 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;

	do {

		cFYI(1, "get dentry for %s", pstart);

		struct inode *dir = dentry->d_inode;



		struct dentry *child;

		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");

		/* skip separators */

		if (dchild->d_inode == NULL) {

		while (*s == sep)

			cFYI(1, "not exists");

			s++;

			inode = NULL;

		if (!*s)

			if (cifs_sb_master_tcon(CIFS_SB(sb))->unix_ext)

			break;

				rc = cifs_get_inode_info_unix(&inode, full_path,

		p = s++;

							      sb, xid);

		/* next separator */

			else

		while (*s && *s != sep)

				rc = cifs_get_inode_info(&inode, full_path,

			s++;

							 NULL, sb, xid, NULL);



			if (rc) {

		mutex_lock(&dir->i_mutex);

				dput(dchild);

		child = lookup_one_len(p, dentry, s - p);

				dput(dparent);

		mutex_unlock(&dir->i_mutex);

				dparent = ERR_PTR(rc);

		dput(dentry);

				goto out;

		dentry = child;

			}

	} while (!IS_ERR(dentry));

			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:

	_FreeXid(xid);

	_FreeXid(xid);

	kfree(full_path);

	kfree(full_path);

	return dparent;

	return dentry;

}

}





static int cifs_set_super(struct super_block *sb, void *data)

static int cifs_set_super(struct super_block *sb, void *data)

fs/namei.c

+6 −1
Original line number Original line Diff line number Diff line
@@ -942,7 +942,6 @@ static bool __follow_mount_rcu(struct nameidata *nd, struct path *path, 
		 * Don't forget we might have a non-mountpoint managed dentry

		 * Don't forget we might have a non-mountpoint managed dentry

		 * that wants to block transit.

		 * that wants to block transit.

		 */

		 */

		*inode = path->dentry->d_inode;

		if (unlikely(managed_dentry_might_block(path->dentry)))

		if (unlikely(managed_dentry_might_block(path->dentry)))

			return false;

			return false;
@@ -955,6 +954,12 @@ static bool __follow_mount_rcu(struct nameidata *nd, struct path *path, 
		path->mnt = mounted;

		path->mnt = mounted;

		path->dentry = mounted->mnt_root;

		path->dentry = mounted->mnt_root;

		nd->seq = read_seqcount_begin(&path->dentry->d_seq);

		nd->seq = read_seqcount_begin(&path->dentry->d_seq);

		/*

		 * Update the inode too. We don't need to re-check the

		 * dentry sequence number here after this d_inode read,

		 * because a mount-point is always pinned.

		 */

		*inode = path->dentry->d_inode;

	}

	}

	return true;

	return true;

}

}