Commit e00da206 authored Aug 02, 2012 by Alexander Block Committed by Chris Mason Aug 09, 2012

Btrfs: remove mnt_want_write call in btrfs_mksubvol



We got a recursive lock in mksubvol because the caller already held
a lock. I think we got into this due to a merge error. Commit a874a63e
removed the mnt_want_write call from btrfs_mksubvol and added a
replacement call to mnt_want_write_file in btrfs_ioctl_snap_create_transid.
Commit e7848683 however tried to move all calls to mnt_want_write above
i_mutex. So somewhere while merging this, it got mixed up. The
solution is to remove the mnt_want_write call completely from
mksubvol.

Reported-by: David Sterba <dave@jikos.cz>
Signed-off-by: Alexander Block <ablock84@googlemail.com>
Signed-off-by: Chris Mason <chris.mason@fusionio.com>

parent 0d7614f0

fs/btrfs/ioctl.c

+0 −5

Original line number	Diff line number	Diff line
		@@ -664,10 +664,6 @@ static noinline int btrfs_mksubvol(struct path *parent,
		struct dentry *dentry;
		int error;

		error = mnt_want_write(parent->mnt);
		if (error)
		return error;

		mutex_lock_nested(&dir->i_mutex, I_MUTEX_PARENT);

		dentry = lookup_one_len(name, parent->dentry, namelen);
		@@ -703,7 +699,6 @@ out_dput:
		dput(dentry);
		out_unlock:
		mutex_unlock(&dir->i_mutex);
		mnt_drop_write(parent->mnt);
		return error;
		}

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