diff mbox

[v2,03/12] NFS: Cache aggressively when file is open for writing

Message ID 1466600806.90993.2.camel@primarydata.com (mailing list archive)
State New, archived
Headers show

Commit Message

Trond Myklebust June 22, 2016, 1:06 p.m. UTC 
Hi Oleg,

Thanks for testing!

On Tue, 2016-06-21 at 18:25 -0400, Oleg Drokin wrote:
> This patch still crashes for me.

> 

> [  183.814855] BUG: unable to handle kernel paging request at

> ffff88001b18cfe8

> [  183.815403] IP: [<ffffffff81381b63>] nfs_update_inode+0x53/0xa30

> [  183.815868] PGD 3580067 PUD 3581067 PMD 77f69067 PTE

> 800000001b18c060

> [  183.816640] Oops: 0000 [#1] SMP DEBUG_PAGEALLOC

> [  183.817252] Modules linked in: loop rpcsec_gss_krb5 joydev

> acpi_cpufreq tpm_tis virtio_console tpm i2c_piix4 pcspkr nfsd ttm

> drm_kms_helper syscopyarea sysfillrect sysimgblt fb_sys_fops

> virtio_blk serio_raw drm floppy

> [  183.820203] CPU: 6 PID: 40935 Comm: rm Not tainted 4.7.0-rc3-vm-

> nfst+ #6

> [  183.820818] Hardware name: Bochs Bochs, BIOS Bochs 01/01/2011

> [  183.821329] task: ffff88001b430c80 ti: ffff88001cf2c000 task.ti:

> ffff88001cf2c000

> [  183.822223] RIP: 0010:[<ffffffff81381b63>]  [<ffffffff81381b63>]

> nfs_update_inode+0x53/0xa30

> [  183.823007] RSP: 0018:ffff88001cf2fb08  EFLAGS: 00010283

> [  183.823417] RAX: ffff88001b18d000 RBX: ffff880021b582a8 RCX:

> 0000000000000000

> [  183.823845] RDX: ffff88001b18d000 RSI: ffff88001c3cdf00 RDI:

> ffff880021b582a8

> [  183.824276] RBP: ffff88001cf2fb58 R08: 0000000000000000 R09:

> 0000000000000001

> [  183.824701] R10: ffff88001b430c80 R11: 00000000fffe3818 R12:

> ffff88001c3cdf00

> [  183.825190] R13: ffff88001c3cdf00 R14: ffff88001c3cdf00 R15:

> 0000000000000001

> [  183.825651] FS:  00007fa0e9c5b700(0000) GS:ffff880075200000(0000)

> knlGS:0000000000000000

> [  183.826396] CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033

> [  183.826884] CR2: ffff88001b18cfe8 CR3: 000000001bc1f000 CR4:

> 00000000000006e0

> [  183.827460] Stack:

> [  183.827825]  ffff880000000000 ffff88001cf2fb58 0000000000000246

> ffffffff81382f33

> [  183.828734]  0000000000000246 ffff880021b582a8 ffff880021b582a8

> ffff88001c3cdf00

> [  183.829634]  ffff88001c3cdf00 0000000000000001 ffff88001cf2fb80

> ffffffff81382aa1

> [  183.830562] Call Trace:

> [  183.830938]  [<ffffffff81382f33>] ?

> nfs_refresh_inode.part.24+0x23/0x50

> [  183.831368]  [<ffffffff81382aa1>]

> nfs_refresh_inode_locked+0x71/0x4e0

> [  183.831785]  [<ffffffff81382f3e>]

> nfs_refresh_inode.part.24+0x2e/0x50

> [  183.832209]  [<ffffffff81384024>]

> __nfs_revalidate_inode+0x314/0x4b0

> [  183.832632]  [<ffffffff8137c6fe>] nfs_do_access+0x47e/0x620

> [  183.833036]  [<ffffffff8137c2d1>] ? nfs_do_access+0x51/0x620

> [  183.833456]  [<ffffffff818507ea>] ? generic_lookup_cred+0x1a/0x20

> [  183.833872]  [<ffffffff8184ef7e>] ? rpcauth_lookupcred+0x8e/0xd0

> [  183.834288]  [<ffffffff8137cb69>] nfs_permission+0x289/0x2e0

> [  183.834699]  [<ffffffff8137c943>] ? nfs_permission+0x63/0x2e0

> [  183.835108]  [<ffffffff812768da>] __inode_permission+0x6a/0xb0

> [  183.835521]  [<ffffffff81276934>] inode_permission+0x14/0x50

> [  183.835928]  [<ffffffff8127b2cf>] link_path_walk+0x2ef/0x6b0

> [  183.837327]  [<ffffffff8127b6a9>] ? path_parentat+0x19/0x80

> [  183.837988]  [<ffffffff8127b6be>] path_parentat+0x2e/0x80

> [  183.838653]  [<ffffffff8127cb13>] filename_parentat+0xb3/0x190

> [  183.839328]  [<ffffffff8123bc4c>] ?

> cache_alloc_debugcheck_after.isra.52+0x19c/0x1f0

> [  183.840533]  [<ffffffff8123e0a0>] ? kmem_cache_alloc+0x300/0x3d0

> [  183.841217]  [<ffffffff8127c89f>] ? getname_flags+0x4f/0x1f0

> [  183.841888]  [<ffffffff810e6d0d>] ? trace_hardirqs_on+0xd/0x10

> [  183.842570]  [<ffffffff8127d455>] do_unlinkat+0x65/0x2f0

> [  183.843243]  [<ffffffff8100201a>] ?

> trace_hardirqs_on_thunk+0x1a/0x1c

> [  183.843910]  [<ffffffff8127e17b>] SyS_unlinkat+0x1b/0x30

> [  183.844582]  [<ffffffff8188aebc>]

> entry_SYSCALL_64_fastpath+0x1f/0xbd

> 

> (gdb) l *(nfs_update_inode+0x53)

> 0xffffffff81381b63 is in nfs_update_inode (/home/green/bk/linux-

> test/fs/nfs/inode.c:1233).

> 1228		 *       being placed at the head of the list.

> 1229		 *       See nfs_inode_attach_open_context()

> 1230		 */

> 1231		return (list_first_entry(&nfsi->open_files,

> 1232				struct nfs_open_context,

> 1233				list)->mode & FMODE_WRITE) ==

> FMODE_WRITE;

> 1234	}

> 1235	

> 1236	static unsigned long nfs_wcc_update_inode(struct inode

> *inode, struct nfs_fattr *fattr)

> 1237	{

> 

> Reverting it makes the crash go away.

> 

> But there's also this other problem that I have not tracked to a

> particular patch yet:

> 

> [   25.830288] =============================================

> [   25.830468] [ INFO: possible recursive locking detected ]

> [   25.830658] 4.7.0-rc3-vm-nfst+ #8 Not tainted

> [   25.830822] ---------------------------------------------

> [   25.831009] cat/6588 is trying to acquire lock:

> [   25.831179]  (&sb->s_type->i_mutex_key#13){++++++}, at:

> [<ffffffff813841f4>] __nfs_revalidate_mapping+0x124/0x3e0

> [   25.832488] 

>                but task is already holding lock:

> [   25.833214]  (&sb->s_type->i_mutex_key#13){++++++}, at:

> [<ffffffff81388b7e>] nfs_start_io_read+0x1e/0x50

> [   25.834209] 

>                other info that might help us debug this:

> [   25.834970]  Possible unsafe locking scenario:

> 

> [   25.835699]        CPU0

> [   25.836077]        ----

> [   25.836459]   lock(&sb->s_type->i_mutex_key#13);

> [   25.836988]   lock(&sb->s_type->i_mutex_key#13);

> [   25.837636] 

>                 *** DEADLOCK ***

> 


The 2 attached patches should hopefully fix these 2 issues and will be
rolled into v3 together with a cleanup patch to remove the now-obsolete 
function nfs_revalidate_mapping_protected().

Cheers
  Trond
  
-- 

Trond Myklebust
Linux NFS client maintainer, PrimaryData
trond.myklebust@primarydata.com

Comments

Oleg Drokin June 22, 2016, 4:19 p.m. UTC | #1 
On Jun 22, 2016, at 9:06 AM, Trond Myklebust wrote:

> Hi Oleg,
> 
> Thanks for testing!
> 
> On Tue, 2016-06-21 at 18:25 -0400, Oleg Drokin wrote:
>> This patch still crashes for me.
>> 
> 
> The 2 attached patches should hopefully fix these 2 issues and will be
> rolled into v3 together with a cleanup patch to remove the now-obsolete 
> function nfs_revalidate_mapping_protected().

Yes, these two seems to be solving the issues.

Thanks.

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diff mbox

Patch

From 65d27ea6cc51cb653c2674666353cf3b8d0f765f Mon Sep 17 00:00:00 2001
From: Trond Myklebust <trond.myklebust@primarydata.com>
Date: Wed, 22 Jun 2016 08:16:54 -0400
Subject: [PATCH 2/2] fixup! NFS: Do not serialise O_DIRECT reads and writes

---
 fs/nfs/file.c | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/fs/nfs/file.c b/fs/nfs/file.c
index fb7a1b0b6a20..9081afacb457 100644
--- a/fs/nfs/file.c
+++ b/fs/nfs/file.c
@@ -171,7 +171,7 @@  nfs_file_read(struct kiocb *iocb, struct iov_iter *to)
 		iov_iter_count(to), (unsigned long) iocb->ki_pos);
 
 	nfs_start_io_read(inode);
-	result = nfs_revalidate_mapping_protected(inode, iocb->ki_filp->f_mapping);
+	result = nfs_revalidate_mapping(inode, iocb->ki_filp->f_mapping);
 	if (!result) {
 		result = generic_file_read_iter(iocb, to);
 		if (result > 0)
@@ -194,7 +194,7 @@  nfs_file_splice_read(struct file *filp, loff_t *ppos,
 		filp, (unsigned long) count, (unsigned long long) *ppos);
 
 	nfs_start_io_read(inode);
-	res = nfs_revalidate_mapping_protected(inode, filp->f_mapping);
+	res = nfs_revalidate_mapping(inode, filp->f_mapping);
 	if (!res) {
 		res = generic_file_splice_read(filp, ppos, pipe, count, flags);
 		if (res > 0)
-- 
2.7.4