linux-stable.git/fs/nfs/write.c, branch linux-4.7.y

nfs: don't create zero-length requests

2016-08-20T16:10:56+00:00

commit 149a4fddd0a72d526abbeac0c8deaab03559836a upstream.

NFS doesn't expect requests with wb_bytes set to zero and may make
unexpected decisions about how to handle that request at the page IO layer.
Skip request creation if we won't have any wb_bytes in the request.

Signed-off-by: Benjamin Coddington 
Signed-off-by: Alexey Dobriyan 
Reviewed-by: Weston Andros Adamson 
Signed-off-by: Trond Myklebust 
Signed-off-by: Greg Kroah-Hartman

nfs: avoid race that crashes nfs_init_commit

2016-05-25T16:59:01+00:00

Since the patch "NFS: Allow multiple commit requests in flight per file"
we can run multiple simultaneous commits on the same inode.  This
introduced a race over collecting pages to commit that made it possible
to call nfs_init_commit() with an empty list - which causes crashes like
the one below.

The fix is to catch this race and avoid calling nfs_init_commit and
initiate_commit when there is no work to do.

Here is the crash:

[600522.076832] BUG: unable to handle kernel NULL pointer dereference at 0000000000000040
[600522.078475] IP: [] nfs_init_commit+0x22/0x130 [nfs]
[600522.078745] PGD 4272b1067 PUD 4272cb067 PMD 0
[600522.078972] Oops: 0000 [#1] SMP
[600522.079204] Modules linked in: nfsv3 nfs_layout_flexfiles rpcsec_gss_krb5 nfsv4 dns_resolver nfs fscache dcdbas ip6t_rpfilter ip6t_REJECT nf_reject_ipv6 xt_conntrack ebtable_nat ebtable_broute bridge stp llc ebtable_filter ebtables ip6table_nat nf_conntrack_ipv6 nf_defrag_ipv6 nf_nat_ipv6 ip6table_mangle ip6table_security ip6table_raw ip6table_filter ip6_tables iptable_nat nf_conntrack_ipv4 nf_defrag_ipv4 nf_nat_ipv4 nf_nat nf_conntrack iptable_mangle iptable_security iptable_raw vmw_vsock_vmci_transport vsock bonding ipmi_devintf ipmi_msghandler coretemp crct10dif_pclmul crc32_pclmul ghash_clmulni_intel ppdev vmw_balloon parport_pc parport acpi_cpufreq vmw_vmci i2c_piix4 shpchp nfsd auth_rpcgss nfs_acl lockd grace sunrpc xfs libcrc32c vmwgfx drm_kms_helper ttm drm crc32c_intel serio_raw vmxnet3
[600522.081380]  vmw_pvscsi ata_generic pata_acpi
[600522.081809] CPU: 3 PID: 15667 Comm: /usr/bin/python Not tainted 4.1.9-100.pd.88.el7.x86_64 #1
[600522.082281] Hardware name: VMware, Inc. VMware Virtual Platform/440BX Desktop Reference Platform, BIOS 6.00 09/30/2014
[600522.082814] task: ffff8800bbbfa780 ti: ffff88042ae84000 task.ti: ffff88042ae84000
[600522.083378] RIP: 0010:[]  [] nfs_init_commit+0x22/0x130 [nfs]
[600522.083973] RSP: 0018:ffff88042ae87438  EFLAGS: 00010246
[600522.084571] RAX: 0000000000000000 RBX: ffff880003485e40 RCX: ffff88042ae87588
[600522.085188] RDX: 0000000000000000 RSI: ffff88042ae874b0 RDI: ffff880003485e40
[600522.085756] RBP: ffff88042ae87448 R08: ffff880003486010 R09: ffff88042ae874b0
[600522.086332] R10: 0000000000000000 R11: 0000000000000005 R12: ffff88042ae872d0
[600522.086905] R13: ffff88042ae874b0 R14: ffff880003485e40 R15: ffff88042704c840
[600522.087484] FS:  00007f4728ff2740(0000) GS:ffff88043fd80000(0000) knlGS:0000000000000000
[600522.088070] CS:  0010 DS: 0000 ES: 0000 CR0: 000000008005003b
[600522.088663] CR2: 0000000000000040 CR3: 000000042b6aa000 CR4: 00000000001406e0
[600522.089327] Stack:
[600522.089926]  0000000000000001 ffff88042ae87588 ffff88042ae874f8 ffffffffa04f09fa
[600522.090549]  0000000000017840 0000000000017840 ffff88042ae87588 ffff8803258d9930
[600522.091169]  ffff88042ae87578 ffffffffa0563d80 0000000000000000 ffff88042704c840
[600522.091789] Call Trace:
[600522.092420]  [] pnfs_generic_commit_pagelist+0x1da/0x320 [nfsv4]
[600522.093052]  [] ? ff_layout_commit_prepare_v3+0x30/0x30 [nfs_layout_flexfiles]
[600522.093696]  [] ff_layout_commit_pagelist+0x15/0x20 [nfs_layout_flexfiles]
[600522.094359]  [] nfs_generic_commit_list+0xe8/0x120 [nfs]
[600522.095032]  [] nfs_commit_inode+0xba/0x110 [nfs]
[600522.095719]  [] nfs_release_page+0x44/0xd0 [nfs]
[600522.096410]  [] try_to_release_page+0x32/0x50
[600522.097109]  [] shrink_page_list+0x961/0xb30
[600522.097812]  [] shrink_inactive_list+0x1cd/0x550
[600522.098530]  [] shrink_lruvec+0x635/0x840
[600522.099250]  [] shrink_zone+0xf0/0x2f0
[600522.099974]  [] do_try_to_free_pages+0x192/0x470
[600522.100709]  [] try_to_free_pages+0xda/0x170
[600522.101464]  [] __alloc_pages_nodemask+0x588/0x970
[600522.102235]  [] alloc_pages_vma+0xb5/0x230
[600522.103000]  [] ? cpumask_any_but+0x39/0x50
[600522.103774]  [] wp_page_copy.isra.55+0x95/0x490
[600522.104558]  [] ? __wake_up+0x48/0x60
[600522.105357]  [] do_wp_page+0xab/0x4f0
[600522.106137]  [] ? release_task+0x36b/0x470
[600522.106902]  [] ? eventfd_ctx_read+0x67/0x1c0
[600522.107659]  [] handle_mm_fault+0xc78/0x1900
[600522.108431]  [] __do_page_fault+0x181/0x420
[600522.109173]  [] ? __audit_syscall_exit+0x1e6/0x280
[600522.109893]  [] do_page_fault+0x30/0x80
[600522.110594]  [] ? syscall_trace_leave+0xc6/0x120
[600522.111288]  [] page_fault+0x28/0x30
[600522.111947] Code: 5d c3 0f 1f 80 00 00 00 00 0f 1f 44 00 00 55 4c 8d 87 d0 01 00 00 48 89 e5 53 48 89 fb 48 83 ec 08 4c 8b 0e 49 8b 41 18 4c 39 ce <48> 8b 40 40 4c 8b 50 30 74 24 48 8b 87 d0 01 00 00 48 8b 7e 08
[600522.113343] RIP  [] nfs_init_commit+0x22/0x130 [nfs]
[600522.114003]  RSP 
[600522.114636] CR2: 0000000000000040

Fixes: af7cf057 (NFS: Allow multiple commit requests in flight per file)
CC: stable@vger.kernel.org
Signed-off-by: Weston Andros Adamson 
Signed-off-by: Anna Schumaker

NFS: checking for NULL instead of IS_ERR() in nfs_commit_file()

2016-05-25T16:11:58+00:00

nfs_create_request() doesn't return NULL, it returns error pointers.

Fixes: 67911c8f18b5 ('NFS: Add nfs_commit_file()')
Signed-off-by: Dan Carpenter 
Signed-off-by: Anna Schumaker

NFS: Reclaim writes via writepage are opportunistic

2016-05-17T19:48:07+00:00

No need to make them a priority any more, or to make them succeed.

Signed-off-by: Trond Myklebust 
Signed-off-by: Anna Schumaker

NFS: Add nfs_commit_file()

2016-05-17T19:47:55+00:00

Copy will use this to set up a commit request for a generic range.  I
don't want to allocate a new pagecache entry for the file, so I needed
to change parts of the commit path to handle requests with a null
wb_page.

Signed-off-by: Anna Schumaker

NFS: Save struct inode * inside nfs_commit_info to clarify usage of i_lock

2016-05-09T13:05:40+00:00

Commit ea2cf22 created nfs_commit_info and saved &inode->i_lock inside
this NFS specific structure.  This obscures the usage of i_lock.
Instead, save struct inode * so later it's clear the spinlock taken is
i_lock.

Should be no functional change.

Signed-off-by: Dave Wysochanski 
Signed-off-by: Anna Schumaker

mm, fs: get rid of PAGE_CACHE_* and page_cache_{get,release} macros

2016-04-04T17:41:08+00:00

PAGE_CACHE_{SIZE,SHIFT,MASK,ALIGN} macros were introduced *long* time
ago with promise that one day it will be possible to implement page
cache with bigger chunks than PAGE_SIZE.

This promise never materialized.  And unlikely will.

We have many places where PAGE_CACHE_SIZE assumed to be equal to
PAGE_SIZE.  And it's constant source of confusion on whether
PAGE_CACHE_* or PAGE_* constant should be used in a particular case,
especially on the border between fs and mm.

Global switching to PAGE_CACHE_SIZE != PAGE_SIZE would cause to much
breakage to be doable.

Let's stop pretending that pages in page cache are special.  They are
not.

The changes are pretty straight-forward:

 -  << (PAGE_CACHE_SHIFT - PAGE_SHIFT) -> ;

 -  >> (PAGE_CACHE_SHIFT - PAGE_SHIFT) -> ;

 - PAGE_CACHE_{SIZE,SHIFT,MASK,ALIGN} -> PAGE_{SIZE,SHIFT,MASK,ALIGN};

 - page_cache_get() -> get_page();

 - page_cache_release() -> put_page();

This patch contains automated changes generated with coccinelle using
script below.  For some reason, coccinelle doesn't patch header files.
I've called spatch for them manually.

The only adjustment after coccinelle is revert of changes to
PAGE_CAHCE_ALIGN definition: we are going to drop it later.

There are few places in the code where coccinelle didn't reach.  I'll
fix them manually in a separate patch.  Comments and documentation also
will be addressed with the separate patch.

virtual patch

@@
expression E;
@@
- E << (PAGE_CACHE_SHIFT - PAGE_SHIFT)
+ E

@@
expression E;
@@
- E >> (PAGE_CACHE_SHIFT - PAGE_SHIFT)
+ E

@@
@@
- PAGE_CACHE_SHIFT
+ PAGE_SHIFT

@@
@@
- PAGE_CACHE_SIZE
+ PAGE_SIZE

@@
@@
- PAGE_CACHE_MASK
+ PAGE_MASK

@@
expression E;
@@
- PAGE_CACHE_ALIGN(E)
+ PAGE_ALIGN(E)

@@
expression E;
@@
- page_cache_get(E)
+ get_page(E)

@@
expression E;
@@
- page_cache_release(E)
+ put_page(E)

Signed-off-by: Kirill A. Shutemov 
Acked-by: Michal Hocko 
Signed-off-by: Linus Torvalds

NFS: Simplify nfs_request_add_commit_list() arguments

2016-01-21T20:54:04+00:00

I noticed that all the callers of this function pass cinfo->mds->list as
an argument in addition to the cinfo structure itself.  Let's get rid of
the extra argument, since it doesn't seem to be adding anything.

Signed-off-by: Anna Schumaker 
Signed-off-by: Trond Myklebust

Merge branch 'bugfixes'

2016-01-07T23:45:36+00:00

* bugfixes:
  SUNRPC: Fixup socket wait for memory
  SUNRPC: Fix a missing break in rpc_anyaddr()
  pNFS/flexfiles: Fix an Oopsable typo in ff_mirror_match_fh()
  NFS: Fix attribute cache revalidation
  NFS: Ensure we revalidate attributes before using execute_ok()
  NFS: Flush reclaim writes using FLUSH_COND_STABLE
  NFS: Background flush should not be low priority
  NFSv4.1/pnfs: Fixup an lo->plh_block_lgets imbalance in layoutreturn
  NFSv4: Don't perform cached access checks before we've OPENed the file
  NFS: Allow the combination pNFS and labeled NFS
  NFS42: handle layoutstats stateid error
  nfs: Fix race in __update_open_stateid()
  nfs: fix missing assignment in nfs4_sequence_done tracepoint

NFS: Use wait_on_atomic_t() for unlock after readahead

2016-01-07T23:42:51+00:00

The use of wait_on_atomic_t() for waiting on I/O to complete before
unlocking allows us to git rid of the NFS_IO_INPROGRESS flag, and thus the
nfs_iocounter's flags member, and finally the nfs_iocounter altogether.
The count of I/O is moved to the lock context, and the counter
increment/decrement functions become simple enough to open-code.

Signed-off-by: Benjamin Coddington 
[Trond: Fix up conflict with existing function nfs_wait_atomic_killable()]
Signed-off-by: Trond Myklebust