On Fri, Aug 3, 2012 at 11:13 PM, Josef Bacik <jbacik@xxxxxxxxxxxx> wrote: > On Thu, Aug 02, 2012 at 05:16:20PM -0600, Alexander Block wrote: >> 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 a874a63 >> 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@xxxxxxxx> >> Signed-off-by: Alexander Block <ablock84@xxxxxxxxxxxxxx> >> --- >> fs/btrfs/ioctl.c | 5 ----- >> 1 file changed, 5 deletions(-) >> >> diff --git a/fs/btrfs/ioctl.c b/fs/btrfs/ioctl.c >> index 00ddf22..9df50fa 100644 >> --- a/fs/btrfs/ioctl.c >> +++ b/fs/btrfs/ioctl.c >> @@ -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; >> } >> > > I'm confused, this isn't here in btrfs-next, so is this a problem still? It's in linus current master. Lio Bo moved the call out of btrfs_mksubvol into the caller. Later a commit from Jan Kara tried to move the call inside mksubvol below i_mutex. If I understand the logs correctly, It was then merged incorrectly. > Thanks, > > Josef -- To unsubscribe from this list: send the line "unsubscribe linux-btrfs" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
