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Commit 5a6059c3 authored by Jeff Mahoney's avatar Jeff Mahoney Committed by Al Viro
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reiserfs: Expand i_mutex to enclose lookup_one_len 



 2.6.30-rc3 introduced some sanity checks in the VFS code to avoid NFS
 bugs by ensuring that lookup_one_len is always called under i_mutex.

 This patch expands the i_mutex locking to enclose lookup_one_len. This was
 always required, but not not enforced in the reiserfs code since it
 does locking around the xattr interactions with the xattr_sem.

 This is obvious enough, and it survived an overnight 50 thread ACL test.

Signed-off-by: default avatarJeff Mahoney <jeffm@suse.com>
Signed-off-by: default avatarAl Viro <viro@zeniv.linux.org.uk>
parent 67e55205

fs/reiserfs/xattr.c

+14 −18
Original line number Diff line number Diff line
@@ -120,25 +120,20 @@ static struct dentry *lookup_or_create_dir(struct dentry *parent, 
	struct dentry *dentry;

	BUG_ON(!parent);



	mutex_lock_nested(&parent->d_inode->i_mutex, I_MUTEX_XATTR);

	dentry = lookup_one_len(name, parent, strlen(name));

	if (IS_ERR(dentry))

		return dentry;

	else if (!dentry->d_inode) {

	if (!IS_ERR(dentry) && !dentry->d_inode) {

		int err = -ENODATA;



		if (xattr_may_create(flags)) {

			mutex_lock_nested(&parent->d_inode->i_mutex,

					  I_MUTEX_XATTR);

		if (xattr_may_create(flags))

			err = xattr_mkdir(parent->d_inode, dentry, 0700);

			mutex_unlock(&parent->d_inode->i_mutex);

		}



		if (err) {

			dput(dentry);

			dentry = ERR_PTR(err);

		}

	}



	mutex_unlock(&parent->d_inode->i_mutex);

	return dentry;

}
@@ -184,6 +179,7 @@ fill_with_dentries(void *buf, const char *name, int namelen, loff_t offset, 
{

	struct reiserfs_dentry_buf *dbuf = buf;

	struct dentry *dentry;

	WARN_ON_ONCE(!mutex_is_locked(&dbuf->xadir->d_inode->i_mutex));



	if (dbuf->count == ARRAY_SIZE(dbuf->dentries))

		return -ENOSPC;
@@ -349,6 +345,7 @@ static struct dentry *xattr_lookup(struct inode *inode, const char *name, 
	if (IS_ERR(xadir))

		return ERR_CAST(xadir);



	mutex_lock_nested(&xadir->d_inode->i_mutex, I_MUTEX_XATTR);

	xafile = lookup_one_len(name, xadir, strlen(name));

	if (IS_ERR(xafile)) {

		err = PTR_ERR(xafile);
@@ -360,18 +357,15 @@ static struct dentry *xattr_lookup(struct inode *inode, const char *name, 


	if (!xafile->d_inode) {

		err = -ENODATA;

		if (xattr_may_create(flags)) {

			mutex_lock_nested(&xadir->d_inode->i_mutex,

					  I_MUTEX_XATTR);

		if (xattr_may_create(flags))

			err = xattr_create(xadir->d_inode, xafile,

					      0700|S_IFREG);

			mutex_unlock(&xadir->d_inode->i_mutex);

		}

	}



	if (err)

		dput(xafile);

out:

	mutex_unlock(&xadir->d_inode->i_mutex);

	dput(xadir);

	if (err)

		return ERR_PTR(err);
@@ -435,6 +429,7 @@ static int lookup_and_delete_xattr(struct inode *inode, const char *name) 
	if (IS_ERR(xadir))

		return PTR_ERR(xadir);



	mutex_lock_nested(&xadir->d_inode->i_mutex, I_MUTEX_XATTR);

	dentry = lookup_one_len(name, xadir, strlen(name));

	if (IS_ERR(dentry)) {

		err = PTR_ERR(dentry);
@@ -442,14 +437,13 @@ static int lookup_and_delete_xattr(struct inode *inode, const char *name) 
	}



	if (dentry->d_inode) {

		mutex_lock_nested(&xadir->d_inode->i_mutex, I_MUTEX_XATTR);

		err = xattr_unlink(xadir->d_inode, dentry);

		mutex_unlock(&xadir->d_inode->i_mutex);

		update_ctime(inode);

	}



	dput(dentry);

out_dput:

	mutex_unlock(&xadir->d_inode->i_mutex);

	dput(xadir);

	return err;

}
@@ -906,9 +900,9 @@ static int create_privroot(struct dentry *dentry) 
{

	int err;

	struct inode *inode = dentry->d_parent->d_inode;

	mutex_lock_nested(&inode->i_mutex, I_MUTEX_XATTR);

	WARN_ON_ONCE(!mutex_is_locked(&inode->i_mutex));



	err = xattr_mkdir(inode, dentry, 0700);

	mutex_unlock(&inode->i_mutex);

	if (err) {

		dput(dentry);

		dentry = NULL;
@@ -980,6 +974,7 @@ int reiserfs_xattr_init(struct super_block *s, int mount_flags) 
	/* If we don't have the privroot located yet - go find it */

	if (!REISERFS_SB(s)->priv_root) {

		struct dentry *dentry;

		mutex_lock_nested(&s->s_root->d_inode->i_mutex, I_MUTEX_CHILD);

		dentry = lookup_one_len(PRIVROOT_NAME, s->s_root,

					strlen(PRIVROOT_NAME));

		if (!IS_ERR(dentry)) {
@@ -993,6 +988,7 @@ int reiserfs_xattr_init(struct super_block *s, int mount_flags) 
			}

		} else

			err = PTR_ERR(dentry);

		mutex_unlock(&s->s_root->d_inode->i_mutex);



		if (!err && dentry) {

			s->s_root->d_op = &xattr_lookup_poison_ops;