I have discussed that shortly with Jack and he suspects that xfs specific part of the iomap callbacks doesn't cancel reservations. Let's CC more xfs people. The thread starts http://lkml.kernel.org/r/20170210035348.GA7075@xxxxxxxxxxxxxxxxxxxxxxxx On Fri 10-02-17 10:31:31, Michal Hocko wrote: > [CC Christoph] > > On Fri 10-02-17 09:02:10, Michal Hocko wrote: > > On Fri 10-02-17 08:14:18, Michal Hocko wrote: > > > On Fri 10-02-17 11:53:48, Eryu Guan wrote: > > > > Hi, > > > > > > > > I was testing 4.10-rc7 kernel and noticed that xfs_repair reported XFS > > > > corruption after fstests xfs/297 test. This didn't happen with 4.10-rc6 > > > > kernel, and git bisect pointed the first bad commit to > > > > > > > > commit d1908f52557b3230fbd63c0429f3b4b748bf2b6d > > > > Author: Michal Hocko <mhocko@xxxxxxxx> > > > > Date: Fri Feb 3 13:13:26 2017 -0800 > > > > > > > > fs: break out of iomap_file_buffered_write on fatal signals > > > > > > > > Tetsuo has noticed that an OOM stress test which performs large write > > > > requests can cause the full memory reserves depletion. He has tracked > > > > this down to the following path > > > > .... > > > > > > > > It's the sb_fdblocks field reports inconsistency: > > > > ... > > > > Phase 2 - using internal log > > > > - zero log... > > > > - scan filesystem freespace and inode maps... > > > > sb_fdblocks 3367765, counted 3367863 > > > > - 11:37:41: scanning filesystem freespace - 16 of 16 allocation groups done > > > > - found root inode chunk > > > > ... > > > > > > > > And it can be reproduced almost 100% with all XFS test configurations > > > > (e.g. xfs_4k xfs_2k_reflink), on all test hosts I tried (so I didn't > > > > bother pasting my detailed test and host configs, if more info is needed > > > > please let me know). > > > > > > The patch can lead to short writes when the task is killed. Was there > > > any OOM killer triggered during the test? If not who is killing the > > > task? I will try to reproduce later today. > > > > I have checked both tests and they are killing the test but none of them > > seems to be using SIGKILL. The patch should make a difference only for > > fatal signal (aka SIGKILL). Is there any other part that can do SIGKILL > > except for the OOM killer? > > I have done > diff --git a/fs/dax.c b/fs/dax.c > index c45598b912e1..4de00ceaf73d 100644 > --- a/fs/dax.c > +++ b/fs/dax.c > @@ -1032,6 +1032,7 @@ dax_iomap_actor(struct inode *inode, loff_t pos, loff_t length, void *data, > ssize_t map_len; > > if (fatal_signal_pending(current)) { > + WARN(1, "dax_iomap_actor\n"); > ret = -EINTR; > break; > } > diff --git a/fs/iomap.c b/fs/iomap.c > index a51cb4c07d4d..00019e2cdad3 100644 > --- a/fs/iomap.c > +++ b/fs/iomap.c > @@ -114,8 +114,10 @@ iomap_write_begin(struct inode *inode, loff_t pos, unsigned len, unsigned flags, > > BUG_ON(pos + len > iomap->offset + iomap->length); > > - if (fatal_signal_pending(current)) > + if (fatal_signal_pending(current)) { > + WARN(1, "iomap_write_begin\n"); > return -EINTR; > + } > > page = grab_cache_page_write_begin(inode->i_mapping, index, flags); > if (!page) > > and it triggered > [ 135.055682] WARNING: CPU: 2 PID: 4894 at fs/iomap.c:118 iomap_write_begin+0x72/0x12c > [ 135.087297] WARNING: CPU: 1 PID: 4899 at fs/iomap.c:118 iomap_write_begin+0x72/0x12c > [ 135.150542] WARNING: CPU: 2 PID: 4857 at fs/iomap.c:118 iomap_write_begin+0x72/0x12c > [ 135.153653] WARNING: CPU: 3 PID: 4889 at fs/iomap.c:118 iomap_write_begin+0x72/0x12c > [ 135.154413] WARNING: CPU: 0 PID: 4929 at fs/iomap.c:118 iomap_write_begin+0x72/0x12c > [ 135.154734] WARNING: CPU: 3 PID: 4934 at fs/iomap.c:118 iomap_write_begin+0x72/0x12c > [ 135.162743] WARNING: CPU: 0 PID: 4813 at fs/iomap.c:118 iomap_write_begin+0x72/0x12c > [ 135.163282] WARNING: CPU: 1 PID: 4891 at fs/iomap.c:118 iomap_write_begin+0x72/0x12c > [ 135.163820] WARNING: CPU: 0 PID: 4932 at fs/iomap.c:118 iomap_write_begin+0x72/0x12c > [ 135.169112] WARNING: CPU: 0 PID: 4923 at fs/iomap.c:118 iomap_write_begin+0x72/0x12c > [ 135.182816] WARNING: CPU: 0 PID: 4892 at fs/iomap.c:118 iomap_write_begin+0x72/0x12c > [ 135.321991] WARNING: CPU: 3 PID: 4872 at fs/iomap.c:118 iomap_write_begin+0x72/0x12c > > always from > [ 135.055682] WARNING: CPU: 2 PID: 4894 at fs/iomap.c:118 iomap_write_begin+0x72/0x12c > [ 135.057092] iomap_write_begin > [ 135.057556] Modules linked in: xfs libcrc32c > [ 135.058191] CPU: 2 PID: 4894 Comm: fsstress Tainted: G W 4.10.0-rc6-test1-00149-gd1908f52557b-dirty #1064 > [ 135.060349] Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS 1.10.1-1 04/01/2014 > [ 135.060865] Call Trace: > [ 135.060865] dump_stack+0x68/0x92 > [ 135.060865] __warn+0xc2/0xdd > [ 135.060865] warn_slowpath_fmt+0x4b/0x53 > [ 135.060865] iomap_write_begin+0x72/0x12c > [ 135.060865] iomap_write_actor+0x99/0x161 > [ 135.060865] iomap_apply+0x9e/0xec > [ 135.060865] ? iomap_write_end+0x62/0x62 > [ 135.060865] iomap_file_buffered_write+0x5b/0x7f > [ 135.060865] ? iomap_write_end+0x62/0x62 > [ 135.060865] xfs_file_buffered_aio_write+0x187/0x2b4 [xfs] > [ 135.060865] xfs_file_write_iter+0x93/0x11c [xfs] > [ 135.060865] __vfs_write+0xcc/0xf5 > [ 135.060865] vfs_write+0x100/0x1a9 > [ 135.060865] SyS_write+0x51/0x8e > > So somebody had to send SIGKILL to fsstress. Anyway, I am wondering > whether this is really a regression. xfs_file_buffered_aio_write used to > call generic_perform_write which does the same thing. > -- > Michal Hocko > SUSE Labs -- Michal Hocko SUSE Labs
