On Fri, Jul 10, 2015 at 09:40:12AM +1000, Dave Chinner wrote: > On Thu, Jul 09, 2015 at 07:45:45PM +0200, Lukas Czerner wrote: > > Currently we can end up in a deadlock because of broken > > sb_start_write -> s_umount ordering. > > > > The race goes like this: > > > > - write the file > > - unlink the file - final_iput will not be calles as file is opened > > - freeze the file system > > - Now simultaneously close the file and call sync (or syncfs on that > > particular file system). Sync will get to wait_sb_inodes() where it will > > grab the referece to the inode (__iget()) and later to call iput(). > > This problem goes away with the sync scalability patchset that josef > has been trying to get merged: > > git://git.kernel.org/pub/scm/linux/kernel/git/josef/btrfs-next.git superblock-scaling > > That patchset removes the full sb inodes list walk in > wait_sb_inodes() and replaces it with a walk of inodes cleaned > during the sync, which will be an empty list in the case of sync > running on an empty filesystem. This commit does the work: s/empty/frozen -Dave. -- Dave Chinner david@xxxxxxxxxxxxx -- To unsubscribe from this list: send the line "unsubscribe linux-fsdevel" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
