linux-toradex.git/fs/nfs/write.c, branch v4.15

nfs: don't wait on commit in nfs_commit_inode() if there were no commit requests

2017-12-15T19:31:50+00:00

If there were no commit requests, then nfs_commit_inode() should not
wait on the commit or mark the inode dirty, otherwise the following
BUG_ON can be triggered:

[ 1917.130762] kernel BUG at fs/inode.c:578!
[ 1917.130766] Oops: Exception in kernel mode, sig: 5 [#1]
[ 1917.130768] SMP NR_CPUS=2048 NUMA pSeries
[ 1917.130772] Modules linked in: iscsi_tcp libiscsi_tcp libiscsi scsi_transport_iscsi blocklayoutdriver rpcsec_gss_krb5 auth_rpcgss nfsv4 dns_resolver nfs lockd grace fscache sunrpc sg nx_crypto pseries_rng ip_tables xfs libcrc32c sd_mod crc_t10dif crct10dif_generic crct10dif_common ibmvscsi scsi_transport_srp ibmveth scsi_tgt dm_mirror dm_region_hash dm_log dm_mod
[ 1917.130805] CPU: 2 PID: 14923 Comm: umount.nfs4 Tainted: G               ------------ T 3.10.0-768.el7.ppc64 #1
[ 1917.130810] task: c0000005ecd88040 ti: c00000004cea0000 task.ti: c00000004cea0000
[ 1917.130813] NIP: c000000000354178 LR: c000000000354160 CTR: c00000000012db80
[ 1917.130816] REGS: c00000004cea3720 TRAP: 0700   Tainted: G               ------------ T  (3.10.0-768.el7.ppc64)
[ 1917.130820] MSR: 8000000100029032   CR: 22002822  XER: 20000000
[ 1917.130828] CFAR: c00000000011f594 SOFTE: 1
GPR00: c000000000354160 c00000004cea39a0 c0000000014c4700 c0000000018cc750
GPR04: 000000000000c750 80c0000000000000 0600000000000000 04eeb76bea749a03
GPR08: 0000000000000034 c0000000018cc758 0000000000000001 d000000005e619e8
GPR12: c00000000012db80 c000000007b31200 0000000000000000 0000000000000000
GPR16: 0000000000000000 0000000000000000 0000000000000000 0000000000000000
GPR20: 0000000000000000 0000000000000000 0000000000000000 0000000000000000
GPR24: 0000000000000000 c000000000dfc3ec 0000000000000000 c0000005eefc02c0
GPR28: d0000000079dbd50 c0000005b94a02c0 c0000005b94a0250 c0000005b94a01c8
[ 1917.130867] NIP [c000000000354178] .evict+0x1c8/0x350
[ 1917.130871] LR [c000000000354160] .evict+0x1b0/0x350
[ 1917.130873] Call Trace:
[ 1917.130876] [c00000004cea39a0] [c000000000354160] .evict+0x1b0/0x350 (unreliable)
[ 1917.130880] [c00000004cea3a30] [c0000000003558cc] .evict_inodes+0x13c/0x270
[ 1917.130884] [c00000004cea3af0] [c000000000327d20] .kill_anon_super+0x70/0x1e0
[ 1917.130896] [c00000004cea3b80] [d000000005e43e30] .nfs_kill_super+0x20/0x60 [nfs]
[ 1917.130900] [c00000004cea3c00] [c000000000328a20] .deactivate_locked_super+0xa0/0x1b0
[ 1917.130903] [c00000004cea3c80] [c00000000035ba54] .cleanup_mnt+0xd4/0x180
[ 1917.130907] [c00000004cea3d10] [c000000000119034] .task_work_run+0x114/0x150
[ 1917.130912] [c00000004cea3db0] [c00000000001ba6c] .do_notify_resume+0xcc/0x100
[ 1917.130916] [c00000004cea3e30] [c00000000000a7b0] .ret_from_except_lite+0x5c/0x60
[ 1917.130919] Instruction dump:
[ 1917.130921] 7fc3f378 486734b5 60000000 387f00a0 38800003 4bdcb365 60000000 e95f00a0
[ 1917.130927] 694a0060 7d4a0074 794ad182 694a0001 <0b0a0000> 892d02a4 2f890000 40de0134

Signed-off-by: Scott Mayhew 
Cc: stable@vger.kernel.org # 4.5+
Signed-off-by: Anna Schumaker

nfs/write: Use common error handling code in nfs_lock_and_join_requests()

2017-11-17T21:43:50+00:00

Add a jump target so that a bit of exception handling can be better reused
at the end of this function.

This issue was detected by using the Coccinelle software.

Signed-off-by: Markus Elfring 
Signed-off-by: Anna Schumaker

NFS: various changes relating to reporting IO errors.

2017-09-12T02:28:56+00:00

1/ remove 'start' and 'end' args from nfs_file_fsync_commit().
   They aren't used.

2/ Make nfs_context_set_write_error() a "static inline" in internal.h
   so we can...

3/ Use nfs_context_set_write_error() instead of mapping_set_error()
   if nfs_pageio_add_request() fails before sending any request.
   NFS generally keeps errors in the open_context, not the mapping,
   so this is more consistent.

4/ If filemap_write_and_write_range() reports any error, still
   check ctx->error.  The value in ctx->error is likely to be
   more useful.  As part of this, NFS_CONTEXT_ERROR_WRITE is
   cleared slightly earlier, before nfs_file_fsync_commit() is called,
   rather than at the start of that function.

Signed-off-by: NeilBrown 
Signed-off-by: Trond Myklebust

NFS: Add static NFS I/O tracepoints

2017-09-12T02:20:38+00:00

Tools like tcpdump and rpcdebug can be very useful. But there are
plenty of environments where they are difficult or impossible to
use. For example, we've had customers report I/O failures during
workloads so heavy that collecting network traffic or enabling
RPC debugging are themselves onerous.

The kernel's static tracepoints are lightweight (less likely to
introduce timing changes) and efficient (the trace data is compact).
They also work in scenarios where capturing network traffic is not
possible due to lack of hardware support (some InfiniBand HCAs) or
where data or network privacy is a concern.

Introduce tracepoints that show when an NFS READ, WRITE, or COMMIT
is initiated, and when it completes. Record the arguments and
results of each operation, which are not shown by existing sunrpc
module's tracepoints.

For instance, the recorded offset and count can be used to match an
"initiate" event to a "done" event. If an NFS READ result returns
fewer bytes than requested or zero, seeing the EOF flag can be
probative. Seeing an NFS4ERR_BAD_STATEID result is also indication
of a particular class of problems. The timing information attached
to each event record can often be useful as well.

Usage example:

[root@manet tmp]# trace-cmd record -e nfs:*initiate* -e nfs:*done
/sys/kernel/debug/tracing/events/nfs/*initiate*/filter
/sys/kernel/debug/tracing/events/nfs/*done/filter
Hit Ctrl^C to stop recording
^CKernel buffer statistics:
  Note: "entries" are the entries left in the kernel ring buffer and are not
        recorded in the trace data. They should all be zero.

CPU: 0
entries: 0
overrun: 0
commit overrun: 0
bytes: 3680
oldest event ts:    78.367422
now ts:   100.124419
dropped events: 0
read events: 74

... and so on.

Signed-off-by: Chuck Lever 
Signed-off-by: Trond Myklebust

NFS: Count the bytes of skipped subrequests in nfs_lock_and_join_requests()

2017-09-09T20:43:09+00:00

If we skip a subrequest due to a zero refcount, we should still count
the byte range that it covered so that we accurately reconstruct the
original request size.

Signed-off-by: Trond Myklebust

NFS: Don't hold the group lock when calling nfs_release_request()

2017-09-09T19:36:40+00:00

That can deadlock if this is the last reference since
nfs_page_group_destroy() calls nfs_page_group_sync_on_bit().
Note that even if the page was removed from the subpage list,
the req->wb_head could still be pointing to the old head.

Signed-off-by: Trond Myklebust

NFS: Remove pnfs_generic_transfer_commit_list()

2017-09-09T16:51:40+00:00

It's pretty much a duplicate of nfs_scan_commit_list() that also
clears the PG_COMMIT_TO_DS flag.

Signed-off-by: Trond Myklebust

NFS: nfs_lock_and_join_requests and nfs_scan_commit_list can deadlock

2017-09-09T16:28:01+00:00

Since the commit list is not ordered, it is possible for nfs_scan_commit_list
to hold a request that nfs_lock_and_join_requests() is waiting for, while
at the same time trying to grab a request that nfs_lock_and_join_requests
already holds.

Signed-off-by: Trond Myklebust

NFS: don't expect errors from mempool_alloc().

2017-09-06T16:31:15+00:00

Commit fbe77c30e9ab ("NFS: move rw_mode to nfs_pageio_header")
reintroduced some pointless code that commit 518662e0fcb9 ("NFS: fix
usage of mempools.") had recently removed.

Remove it again.

Cc: Benjamin Coddington 
Signed-off-by: NeilBrown 
Signed-off-by: Trond Myklebust

Merge branch 'bugfixes'

2017-08-20T17:04:12+00:00