When the system is close-to-OOM, fsync() may fail due to -ENOMEM because xfs_log_reserve() is using KM_MAYFAIL. It is a bad thing to fail writeback operation due to user-triggerable OOM condition. Since we are not using KM_MAYFAIL at xfs_trans_alloc() before calling xfs_log_reserve(), let's use the same flags at xfs_log_reserve(). oom-torture: page allocation failure: order:0, mode:0x46c40(GFP_NOFS|__GFP_NOWARN|__GFP_RETRY_MAYFAIL|__GFP_COMP), nodemask=(null) CPU: 7 PID: 1662 Comm: oom-torture Kdump: loaded Not tainted 5.3.0-rc2+ #925 Hardware name: VMware, Inc. VMware Virtual Platform/440BX Desktop Reference Platform, BIOS 6.00 Call Trace: dump_stack+0x67/0x95 warn_alloc+0xa9/0x140 __alloc_pages_slowpath+0x9a8/0xbce __alloc_pages_nodemask+0x372/0x3b0 alloc_slab_page+0x3a/0x8d0 new_slab+0x330/0x420 ___slab_alloc.constprop.94+0x879/0xb00 __slab_alloc.isra.89.constprop.93+0x43/0x6f kmem_cache_alloc+0x331/0x390 kmem_zone_alloc+0x9f/0x110 [xfs] kmem_zone_alloc+0x9f/0x110 [xfs] xlog_ticket_alloc+0x33/0xd0 [xfs] xfs_log_reserve+0xb4/0x410 [xfs] xfs_trans_reserve+0x1d1/0x2b0 [xfs] xfs_trans_alloc+0xc9/0x250 [xfs] xfs_setfilesize_trans_alloc.isra.27+0x44/0xc0 [xfs] xfs_submit_ioend.isra.28+0xa5/0x180 [xfs] xfs_vm_writepages+0x76/0xa0 [xfs] do_writepages+0x17/0x80 __filemap_fdatawrite_range+0xc1/0xf0 file_write_and_wait_range+0x53/0xa0 xfs_file_fsync+0x87/0x290 [xfs] vfs_fsync_range+0x37/0x80 do_fsync+0x38/0x60 __x64_sys_fsync+0xf/0x20 do_syscall_64+0x4a/0x1c0 entry_SYSCALL_64_after_hwframe+0x49/0xbe Signed-off-by: Tetsuo Handa <penguin-kernel@xxxxxxxxxxxxxxxxxxx> --- fs/xfs/xfs_log.c | 5 +---- 1 file changed, 1 insertion(+), 4 deletions(-) diff --git a/fs/xfs/xfs_log.c b/fs/xfs/xfs_log.c index 00e9f5c388d3..7fc3c1ad36bc 100644 --- a/fs/xfs/xfs_log.c +++ b/fs/xfs/xfs_log.c @@ -429,10 +429,7 @@ xfs_log_reserve( ASSERT(*ticp == NULL); tic = xlog_ticket_alloc(log, unit_bytes, cnt, client, permanent, - KM_SLEEP | KM_MAYFAIL); - if (!tic) - return -ENOMEM; - + KM_SLEEP); *ticp = tic; xlog_grant_push_ail(log, tic->t_cnt ? tic->t_unit_res * tic->t_cnt -- 2.16.5
