pnfs: fix lockup caused by pnfs_generic_pg_test
end_offset and req_offset both return u64 - avoid casting to u32
until it's needed, when it's less than the (u32) size returned by
nfs_generic_pg_test.
Also, fix the comments in pnfs_generic_pg_test.
Running the cthon04 special tests caused this lockup in the
"write/read at 2GB, 4GB edges" test when running against a file layout server:
BUG: soft lockup - CPU#0 stuck for 22s! [bigfile2:823]
Modules linked in: nfs_layout_nfsv41_files rpcsec_gss_krb5 nfsv4 nfs fscache ip6t_REJECT nf_conntrack_ipv6 nf_defrag_ipv6 ip6table_mangle ip6table_filter ip6_tables iptable_nat nf_nat_ipv4 nf_nat iptable_mangle ppdev crc32c_intel aesni_intel aes_x86_64 glue_helper lrw gf128mul ablk_helper cryptd serio_raw e1000 shpchp i2c_piix4 i2c_core parport_pc parport nfsd auth_rpcgss oid_registry exportfs nfs_acl lockd sunrpc btrfs xor zlib_deflate raid6_pq mptspi scsi_transport_spi mptscsih mptbase ata_generic floppy autofs4
irq event stamp: 205958
hardirqs last enabled at (205957): [<ffffffff814a62dc>] restore_args+0x0/0x30
hardirqs last disabled at (205958): [<ffffffff814ad96a>] apic_timer_interrupt+0x6a/0x80
softirqs last enabled at (205956): [<ffffffff8103ffb2>] __do_softirq+0x1ea/0x2ab
softirqs last disabled at (205951): [<ffffffff8104026d>] irq_exit+0x44/0x9a
CPU: 0 PID: 823 Comm: bigfile2 Not tainted 3.15.0-rc1-branch-pgio_plus+ #3
Hardware name: VMware, Inc. VMware Virtual Platform/440BX Desktop Reference Platform, BIOS 6.00 07/31/2013
task: ffff8800792ec480 ti: ffff880078c4e000 task.ti: ffff880078c4e000
RIP: 0010:[<ffffffffa02ce51f>] [<ffffffffa02ce51f>] nfs_page_group_unlock+0x3e/0x4b [nfs]
RSP: 0018:ffff880078c4fab0 EFLAGS: 00000202
RAX: 0000000000000fff RBX: ffff88006bf83300 RCX: 0000000000000000
RDX: 0000000000000001 RSI: 0000000000000000 RDI: ffff88006bf83300
RBP: ffff880078c4fab8 R08: 0000000000000001 R09: 0000000000000000
R10: ffffffff8249840c R11: 0000000000000000 R12: 0000000000000035
R13: ffff88007ffc72d8 R14: 0000000000000001 R15: 0000000000000000
FS: 00007f45f11b7740(0000) GS:ffff88007f200000(0000) knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007f3a8cb632d0 CR3: 000000007931c000 CR4: 00000000001407f0
Stack:
ffff88006bf832c0 ffff880078c4fb00 ffffffffa02cec22 ffff880078c4fad8
00000fff810f9d99 ffff880078c4fca0 ffff88006bf832c0 ffff88006bf832c0
ffff880078c4fca0 ffff880078c4fd60 ffff880078c4fb28 ffffffffa02cee34
Call Trace:
[<ffffffffa02cec22>] __nfs_pageio_add_request+0x298/0x34f [nfs]
[<ffffffffa02cee34>] nfs_pageio_add_request+0x1f/0x42 [nfs]
[<ffffffffa02d1722>] nfs_do_writepage+0x1b5/0x1e4 [nfs]
[<ffffffffa02d1764>] nfs_writepages_callback+0x13/0x25 [nfs]
[<ffffffffa02d1751>] ? nfs_do_writepage+0x1e4/0x1e4 [nfs]
[<ffffffff810eb32d>] write_cache_pages+0x254/0x37f
[<ffffffffa02d1751>] ? nfs_do_writepage+0x1e4/0x1e4 [nfs]
[<ffffffff8149cf9e>] ? printk+0x54/0x56
[<ffffffff810eacca>] ? __set_page_dirty_nobuffers+0x22/0xe9
[<ffffffffa016d864>] ? put_rpccred+0x38/0x101 [sunrpc]
[<ffffffffa02d1ae1>] nfs_writepages+0xb4/0xf8 [nfs]
[<ffffffff810ec59c>] do_writepages+0x21/0x2f
[<ffffffff810e36e8>] __filemap_fdatawrite_range+0x55/0x57
[<ffffffff810e374a>] filemap_write_and_wait_range+0x2d/0x5b
[<ffffffffa030ba0a>] nfs4_file_fsync+0x3a/0x98 [nfsv4]
[<ffffffff8114ee3c>] vfs_fsync_range+0x18/0x20
[<ffffffff810e40c2>] generic_file_aio_write+0xa7/0xbd
[<ffffffffa02c5c6b>] nfs_file_write+0xf0/0x170 [nfs]
[<ffffffff81129215>] do_sync_write+0x59/0x78
[<ffffffff8112956c>] vfs_write+0xab/0x107
[<ffffffff81129c8b>] SyS_write+0x49/0x7f
[<ffffffff814acd12>] system_call_fastpath+0x16/0x1b
Reported-by: Anna Schumaker <Anna.Schumaker@netapp.com>
Signed-off-by: Weston Andros Adamson <dros@primarydata.com>
Signed-off-by: Trond Myklebust <trond.myklebust@primarydata.com>
diff --git a/fs/nfs/pnfs.c b/fs/nfs/pnfs.c
index ce46a41..ee60c42 100644
--- a/fs/nfs/pnfs.c
+++ b/fs/nfs/pnfs.c
@@ -1433,33 +1433,37 @@
struct nfs_page *req)
{
unsigned int size;
- u64 end;
+ u64 seg_end, req_start, seg_left;
size = nfs_generic_pg_test(pgio, prev, req);
if (!size)
return 0;
/*
- * Test if a nfs_page is fully contained in the pnfs_layout_range.
- * Note that this test makes several assumptions:
- * - that the previous nfs_page in the struct nfs_pageio_descriptor
- * is known to lie within the range.
- * - that the nfs_page being tested is known to be contiguous with the
- * previous nfs_page.
- * - Layout ranges are page aligned, so we only have to test the
- * start offset of the request.
+ * 'size' contains the number of bytes left in the current page (up
+ * to the original size asked for in @req->wb_bytes).
+ *
+ * Calculate how many bytes are left in the layout segment
+ * and if there are less bytes than 'size', return that instead.
*
* Please also note that 'end_offset' is actually the offset of the
* first byte that lies outside the pnfs_layout_range. FIXME?
*
*/
if (pgio->pg_lseg) {
- end = end_offset(pgio->pg_lseg->pls_range.offset,
- pgio->pg_lseg->pls_range.length);
- WARN_ON_ONCE(req_offset(req) > end);
- if (req_offset(req) >= end)
+ seg_end = end_offset(pgio->pg_lseg->pls_range.offset,
+ pgio->pg_lseg->pls_range.length);
+ req_start = req_offset(req);
+ WARN_ON_ONCE(req_start > seg_end);
+ /* start of request is past the last byte of this segment */
+ if (req_start >= seg_end)
return 0;
- size = min((unsigned int)(end - req_offset(req)), size);
+
+ /* adjust 'size' iff there are fewer bytes left in the
+ * segment than what nfs_generic_pg_test returned */
+ seg_left = seg_end - req_start;
+ if (seg_left < size)
+ size = (unsigned int)seg_left;
}
return size;
