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Commit b1c839bb authored by Frederic Weisbecker's avatar Frederic Weisbecker
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kill-the-bkl/reiserfs: don't hold the write recursively in reiserfs_lookup() 



The write lock can be acquired recursively in reiserfs_lookup(). But we may
want to *really* release the lock before possible rescheduling from a
reiserfs_lookup() callee.

Hence we want to only acquire the lock once (ie: not recursively).

[ Impact: prevent from possible false unreleased write lock on sleeping ]

Cc: Jeff Mahoney <jeffm@suse.com>
Cc: Chris Mason <chris.mason@oracle.com>
Cc: Ingo Molnar <mingo@elte.hu>
Cc: Alexander Beregalov <a.beregalov@gmail.com>
Signed-off-by: default avatarFrederic Weisbecker <fweisbec@gmail.com>
parent 26931309

fs/reiserfs/namei.c

+10 −3
Original line number Original line Diff line number Diff line
@@ -324,6 +324,7 @@ static struct dentry *reiserfs_lookup(struct inode *dir, struct dentry *dentry, 
				      struct nameidata *nd)

				      struct nameidata *nd)

{

{

	int retval;

	int retval;

	int lock_depth;

	struct inode *inode = NULL;

	struct inode *inode = NULL;

	struct reiserfs_dir_entry de;

	struct reiserfs_dir_entry de;

	INITIALIZE_PATH(path_to_entry);

	INITIALIZE_PATH(path_to_entry);
@@ -331,7 +332,13 @@ static struct dentry *reiserfs_lookup(struct inode *dir, struct dentry *dentry, 
	if (REISERFS_MAX_NAME(dir->i_sb->s_blocksize) < dentry->d_name.len)

	if (REISERFS_MAX_NAME(dir->i_sb->s_blocksize) < dentry->d_name.len)

		return ERR_PTR(-ENAMETOOLONG);

		return ERR_PTR(-ENAMETOOLONG);





	reiserfs_write_lock(dir->i_sb);

	/*

	 * Might be called with or without the write lock, must be careful

	 * to not recursively hold it in case we want to release the lock

	 * before rescheduling.

	 */

	lock_depth = reiserfs_write_lock_once(dir->i_sb);



	de.de_gen_number_bit_string = NULL;

	de.de_gen_number_bit_string = NULL;

	retval =

	retval =

	    reiserfs_find_entry(dir, dentry->d_name.name, dentry->d_name.len,

	    reiserfs_find_entry(dir, dentry->d_name.name, dentry->d_name.len,
@@ -341,7 +348,7 @@ static struct dentry *reiserfs_lookup(struct inode *dir, struct dentry *dentry, 
		inode = reiserfs_iget(dir->i_sb,

		inode = reiserfs_iget(dir->i_sb,

				      (struct cpu_key *)&(de.de_dir_id));

				      (struct cpu_key *)&(de.de_dir_id));

		if (!inode || IS_ERR(inode)) {

		if (!inode || IS_ERR(inode)) {

			reiserfs_write_unlock(dir->i_sb);

			reiserfs_write_unlock_once(dir->i_sb, lock_depth);

			return ERR_PTR(-EACCES);

			return ERR_PTR(-EACCES);

		}

		}
@@ -350,7 +357,7 @@ static struct dentry *reiserfs_lookup(struct inode *dir, struct dentry *dentry, 
		if (IS_PRIVATE(dir))

		if (IS_PRIVATE(dir))

			inode->i_flags |= S_PRIVATE;

			inode->i_flags |= S_PRIVATE;

	}

	}

	reiserfs_write_unlock(dir->i_sb);

	reiserfs_write_unlock_once(dir->i_sb, lock_depth);

	if (retval == IO_ERROR) {

	if (retval == IO_ERROR) {

		return ERR_PTR(-EIO);

		return ERR_PTR(-EIO);

	}

	}