On Tue, Sep 24, 2024 at 09:40:42AM +0200, Christoph Hellwig wrote: > Hi all, > > this is another fallout from the zoned XFS work, which stresses the XFS > COW I/O path very heavily. It affects normal I/O to reflinked files as > well, but is very hard to hit there. > > The main problem here is that we only punch out delalloc reservations > from the data fork, but COW I/O places delalloc extents into the COW > fork, which means that it won't get punched out forshort writes. > > [Sorry for the rapid fire repost, but as we're down to comment changes > and the series has been fully reviewed except for the trivial > refactoring patch at the beginning I'd like to get it out before being > semi-offline for a few days] Hmmm so I tried applying this series, but now I get this splat: [ 217.170122] run fstests xfs/574 at 2024-10-04 16:36:30 [ 218.248617] XFS (sda3): EXPERIMENTAL online scrub feature in use. Use at your own risk! [ 219.030068] XFS (sda4): EXPERIMENTAL exchange-range feature enabled. Use at your own risk! [ 219.032253] XFS (sda4): EXPERIMENTAL parent pointer feature enabled. Use at your own risk! [ 219.034749] XFS (sda4): Mounting V5 Filesystem 9de8b32b-dada-468a-b83b-f2c702031b67 [ 219.073377] XFS (sda4): Ending clean mount [ 219.076260] XFS (sda4): Quotacheck needed: Please wait. [ 219.083160] XFS (sda4): Quotacheck: Done. [ 219.116532] XFS (sda4): EXPERIMENTAL online scrub feature in use. Use at your own risk! [ 306.312461] INFO: task fsstress:27661 blocked for more than 61 seconds. [ 306.342904] Not tainted 6.12.0-rc1-djwx #rc1 [ 306.344066] "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message. [ 306.345961] task:fsstress state:D stack:11464 pid:27661 tgid:27661 ppid:1 flags:0x00004004 [ 306.348070] Call Trace: [ 306.348722] <TASK> [ 306.349177] __schedule+0x419/0x14c0 [ 306.350024] ? asm_sysvec_apic_timer_interrupt+0x16/0x20 [ 306.351305] schedule+0x2c/0x110 [ 306.352082] schedule_preempt_disabled+0x18/0x30 [ 306.353183] rwsem_down_write_slowpath+0x2a8/0x6a0 [ 306.354229] ? filemap_add_folio+0xc5/0xf0 [ 306.355160] down_write+0x6e/0x70 [ 306.355953] xfs_buffered_write_iomap_end+0xcf/0x130 [xfs 05abef6fe7019e4129a0560dad36f86c40f3b541] [ 306.358115] iomap_iter+0x78/0x2f0 [ 306.358974] iomap_file_unshare+0x82/0x290 [ 306.359935] xfs_reflink_unshare+0xf4/0x170 [xfs 05abef6fe7019e4129a0560dad36f86c40f3b541] [ 306.361787] xfs_file_fallocate+0x13f/0x430 [xfs 05abef6fe7019e4129a0560dad36f86c40f3b541] [ 306.364005] vfs_fallocate+0x110/0x320 [ 306.364984] __x64_sys_fallocate+0x42/0x70 [ 306.365999] do_syscall_64+0x47/0x100 [ 306.366974] entry_SYSCALL_64_after_hwframe+0x4b/0x53 [ 306.368228] RIP: 0033:0x7f893d3b2cb3 [ 306.369064] RSP: 002b:00007ffd32c796d8 EFLAGS: 00000202 ORIG_RAX: 000000000000011d [ 306.370650] RAX: ffffffffffffffda RBX: 000000000000131e RCX: 00007f893d3b2cb3 [ 306.372183] RDX: 000000000002eb27 RSI: 0000000000000041 RDI: 0000000000000005 [ 306.373940] RBP: 0000000000000041 R08: 000000000000005f R09: 0000000000000078 [ 306.375365] R10: 00000000000b0483 R11: 0000000000000202 R12: 0000000000000005 [ 306.376763] R13: 000000000002eb27 R14: 0000000000000000 R15: 00000000000b0483 [ 306.378174] </TASK> I think this series needs to assert that the invalidatelock is held (instead of taking it) for the IOMAP_UNSHARE case too, since UNSHARE is called from fallocate, which has already taken the MMAPLOCK. --D > Changes since v3: > - improve two comments > > Changes since v2: > - drop the patches already merged and rebased to latest Linus' tree > - moved taking invalidate_lock from iomap to the caller to avoid a > too complicated locking protocol > - better document the xfs_file_write_zero_eof return value > - fix a commit log typo > > Changes since v1: > - move the already reviewed iomap prep changes to the beginning in case > Christian wants to take them ASAP > - take the invalidate_lock for post-EOF zeroing so that we have a > consistent locking pattern for zeroing. > > Diffstat: > Documentation/filesystems/iomap/operations.rst | 2 > fs/iomap/buffered-io.c | 111 ++++++------------- > fs/xfs/xfs_aops.c | 4 > fs/xfs/xfs_bmap_util.c | 10 + > fs/xfs/xfs_bmap_util.h | 2 > fs/xfs/xfs_file.c | 146 +++++++++++++++---------- > fs/xfs/xfs_iomap.c | 65 +++++++---- > include/linux/iomap.h | 20 ++- > 8 files changed, 196 insertions(+), 164 deletions(-) >
