Re: Circular lock dep in btrfs triggered by shrinker
On Mon, Oct 22, 2018 at 7:22 PM David Sterba wrote: > > On Mon, Oct 22, 2018 at 03:07:26AM -0700, Olof Johansson wrote: > > I hit the below circular locking dependency. Seems like the assumption made > > in > > 712e36c5f2a7fa56 ("btrfs: use GFP_KERNEL in btrfs_alloc_inode") either isn't > > true, or has since changed? > > I think it must have been there from the beginning. There were reports > of this lockdep warning like the below and IIRC a few more > (https://lkml.kernel.org/r/20180627120523.ga2...@suse.cz), but without a > resolution. > > Incidentally, there was a fix that's now in the 4.20 pull and only after > I had seen your report I realized that it was the fix for the warning: > > https://git.kernel.org/pub/scm/linux/kernel/git/kdave/linux.git/commit/?h=for-4.20-part1=84de76a2fb217dc1b6bc2965cc397d1648aa1404 > > It disables the filesystem allocations using the memalloc_nofs mechanism > around free space inode allocation, while my original patch expected > only regular inodes created by VFS. Ah, great. I'll take that branch for a spin later today and confirm at my end too. -Olof
Re: Circular lock dep in btrfs triggered by shrinker
On Mon, Oct 22, 2018 at 7:22 PM David Sterba wrote: > > On Mon, Oct 22, 2018 at 03:07:26AM -0700, Olof Johansson wrote: > > I hit the below circular locking dependency. Seems like the assumption made > > in > > 712e36c5f2a7fa56 ("btrfs: use GFP_KERNEL in btrfs_alloc_inode") either isn't > > true, or has since changed? > > I think it must have been there from the beginning. There were reports > of this lockdep warning like the below and IIRC a few more > (https://lkml.kernel.org/r/20180627120523.ga2...@suse.cz), but without a > resolution. > > Incidentally, there was a fix that's now in the 4.20 pull and only after > I had seen your report I realized that it was the fix for the warning: > > https://git.kernel.org/pub/scm/linux/kernel/git/kdave/linux.git/commit/?h=for-4.20-part1=84de76a2fb217dc1b6bc2965cc397d1648aa1404 > > It disables the filesystem allocations using the memalloc_nofs mechanism > around free space inode allocation, while my original patch expected > only regular inodes created by VFS. Ah, great. I'll take that branch for a spin later today and confirm at my end too. -Olof