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[RFC 7/8] btrfs: Prevent from early transaction abort

Started bymhocko@kernel.org
First post2015-08-05 12:00 +0200
Last post2015-08-19 14:30 +0200
Articles 7 — 4 participants

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  [RFC 7/8] btrfs: Prevent from early transaction abort mhocko@kernel.org - 2015-08-05 12:00 +0200
    Re: [RFC 7/8] btrfs: Prevent from early transaction abort David Sterba <dsterba@suse.com> - 2015-08-05 18:40 +0200
    [RFC -v2 7/8] btrfs: Prevent from early transaction abort Michal Hocko <mhocko@kernel.org> - 2015-08-18 12:50 +0200
      Re: [RFC -v2 7/8] btrfs: Prevent from early transaction abort Michal Hocko <mhocko@kernel.org> - 2015-08-18 13:10 +0200
      Re: [RFC -v2 7/8] btrfs: Prevent from early transaction abort Chris Mason <clm@fb.com> - 2015-08-18 19:20 +0200
        Re: [RFC -v2 7/8] btrfs: Prevent from early transaction abort Michal Hocko <mhocko@kernel.org> - 2015-08-18 19:30 +0200
          Re: [RFC -v2 7/8] btrfs: Prevent from early transaction abort Michal Hocko <mhocko@kernel.org> - 2015-08-19 14:30 +0200

#1200612 — [RFC 7/8] btrfs: Prevent from early transaction abort

Frommhocko@kernel.org
Date2015-08-05 12:00 +0200
Subject[RFC 7/8] btrfs: Prevent from early transaction abort
Message-ID<pU3Eo-66q-57@gated-at.bofh.it>
From: Michal Hocko <mhocko@suse.com>

Btrfs relies on GFP_NOFS allocation when commiting the transaction but
since "mm: page_alloc: do not lock up GFP_NOFS allocations upon OOM"
those allocations are allowed to fail which can lead to a pre-mature
transaction abort:

[   55.328093] Call Trace:
[   55.328890]  [<ffffffff8154e6f0>] dump_stack+0x4f/0x7b
[   55.330518]  [<ffffffff8108fa28>] ? console_unlock+0x334/0x363
[   55.332738]  [<ffffffff8110873e>] __alloc_pages_nodemask+0x81d/0x8d4
[   55.334910]  [<ffffffff81100752>] pagecache_get_page+0x10e/0x20c
[   55.336844]  [<ffffffffa007d916>] alloc_extent_buffer+0xd0/0x350 [btrfs]
[   55.338973]  [<ffffffffa0059d8c>] btrfs_find_create_tree_block+0x15/0x17 [btrfs]
[   55.341329]  [<ffffffffa004f728>] btrfs_alloc_tree_block+0x18c/0x405 [btrfs]
[   55.343566]  [<ffffffffa003fa34>] split_leaf+0x1e4/0x6a6 [btrfs]
[   55.345577]  [<ffffffffa0040567>] btrfs_search_slot+0x671/0x831 [btrfs]
[   55.347679]  [<ffffffff810682d7>] ? get_parent_ip+0xe/0x3e
[   55.349434]  [<ffffffffa0041cb2>] btrfs_insert_empty_items+0x5d/0xa8 [btrfs]
[   55.351681]  [<ffffffffa004ecfb>] __btrfs_run_delayed_refs+0x7a6/0xf35 [btrfs]
[   55.353979]  [<ffffffffa00512ea>] btrfs_run_delayed_refs+0x6e/0x226 [btrfs]
[   55.356212]  [<ffffffffa0060e21>] ? start_transaction+0x192/0x534 [btrfs]
[   55.358378]  [<ffffffffa0060e21>] ? start_transaction+0x192/0x534 [btrfs]
[   55.360626]  [<ffffffffa0060221>] btrfs_commit_transaction+0x4c/0xaba [btrfs]
[   55.362894]  [<ffffffffa0060e21>] ? start_transaction+0x192/0x534 [btrfs]
[   55.365221]  [<ffffffffa0073428>] btrfs_sync_file+0x29c/0x310 [btrfs]
[   55.367273]  [<ffffffff81186808>] vfs_fsync_range+0x8f/0x9e
[   55.369047]  [<ffffffff81186833>] vfs_fsync+0x1c/0x1e
[   55.370654]  [<ffffffff81186869>] do_fsync+0x34/0x4e
[   55.372246]  [<ffffffff81186ab3>] SyS_fsync+0x10/0x14
[   55.373851]  [<ffffffff81554f97>] system_call_fastpath+0x12/0x6f
[   55.381070] BTRFS: error (device hdb1) in btrfs_run_delayed_refs:2821: errno=-12 Out of memory
[   55.382431] BTRFS warning (device hdb1): Skipping commit of aborted transaction.
[   55.382433] BTRFS warning (device hdb1): cleanup_transaction:1692: Aborting unused transaction(IO failure).
[   55.384280] ------------[ cut here ]------------
[   55.384312] WARNING: CPU: 0 PID: 3010 at fs/btrfs/delayed-ref.c:438 btrfs_select_ref_head+0xd9/0xfe [btrfs]()
[...]
[   55.384337] Call Trace:
[   55.384353]  [<ffffffff8154e6f0>] dump_stack+0x4f/0x7b
[   55.384357]  [<ffffffff8107f717>] ? down_trylock+0x2d/0x37
[   55.384359]  [<ffffffff81046977>] warn_slowpath_common+0xa1/0xbb
[   55.384398]  [<ffffffffa00a1d6b>] ? btrfs_select_ref_head+0xd9/0xfe [btrfs]
[   55.384400]  [<ffffffff81046a34>] warn_slowpath_null+0x1a/0x1c
[   55.384423]  [<ffffffffa00a1d6b>] btrfs_select_ref_head+0xd9/0xfe [btrfs]
[   55.384446]  [<ffffffffa004e5f7>] ? __btrfs_run_delayed_refs+0xa2/0xf35 [btrfs]
[   55.384455]  [<ffffffffa004e600>] __btrfs_run_delayed_refs+0xab/0xf35 [btrfs]
[   55.384476]  [<ffffffffa00512ea>] btrfs_run_delayed_refs+0x6e/0x226 [btrfs]
[   55.384499]  [<ffffffffa0060e21>] ? start_transaction+0x192/0x534 [btrfs]
[   55.384521]  [<ffffffffa0060e21>] ? start_transaction+0x192/0x534 [btrfs]
[   55.384543]  [<ffffffffa0060221>] btrfs_commit_transaction+0x4c/0xaba [btrfs]
[   55.384565]  [<ffffffffa0060e21>] ? start_transaction+0x192/0x534 [btrfs]
[   55.384588]  [<ffffffffa0073428>] btrfs_sync_file+0x29c/0x310 [btrfs]
[   55.384591]  [<ffffffff81186808>] vfs_fsync_range+0x8f/0x9e
[   55.384592]  [<ffffffff81186833>] vfs_fsync+0x1c/0x1e
[   55.384593]  [<ffffffff81186869>] do_fsync+0x34/0x4e
[   55.384594]  [<ffffffff81186ab3>] SyS_fsync+0x10/0x14
[   55.384595]  [<ffffffff81554f97>] system_call_fastpath+0x12/0x6f
[...]
[   55.384608] ---[ end trace c29799da1d4dd621 ]---
[   55.437323] BTRFS info (device hdb1): forced readonly
[   55.438815] BTRFS info (device hdb1): delayed_refs has NO entry

Fix this by reintroducing the no-fail behavior of this allocation path
with the explicit __GFP_NOFAIL.

Signed-off-by: Michal Hocko <mhocko@suse.com>
---
 fs/btrfs/extent_io.c | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/fs/btrfs/extent_io.c b/fs/btrfs/extent_io.c
index c374e1e71e5f..88fad7051e38 100644
--- a/fs/btrfs/extent_io.c
+++ b/fs/btrfs/extent_io.c
@@ -4607,7 +4607,7 @@ __alloc_extent_buffer(struct btrfs_fs_info *fs_info, u64 start,
 {
 	struct extent_buffer *eb = NULL;
 
-	eb = kmem_cache_zalloc(extent_buffer_cache, GFP_NOFS);
+	eb = kmem_cache_zalloc(extent_buffer_cache, GFP_NOFS|__GFP_NOFAIL);
 	if (eb == NULL)
 		return NULL;
 	eb->start = start;
@@ -4867,7 +4867,7 @@ struct extent_buffer *alloc_extent_buffer(struct btrfs_fs_info *fs_info,
 		return NULL;
 
 	for (i = 0; i < num_pages; i++, index++) {
-		p = find_or_create_page(mapping, index, GFP_NOFS);
+		p = find_or_create_page(mapping, index, GFP_NOFS|__GFP_NOFAIL);
 		if (!p)
 			goto free_eb;
 
-- 
2.5.0

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#1200978

FromDavid Sterba <dsterba@suse.com>
Date2015-08-05 18:40 +0200
Message-ID<pU9Tt-6QK-37@gated-at.bofh.it>
In reply to#1200612
On Wed, Aug 05, 2015 at 11:51:23AM +0200, mhocko@kernel.org wrote:
> From: Michal Hocko <mhocko@suse.com>
... 
> Fix this by reintroducing the no-fail behavior of this allocation path
> with the explicit __GFP_NOFAIL.
> 
> Signed-off-by: Michal Hocko <mhocko@suse.com>

Reviewed-by: David Sterba <dsterba@suse.com>
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#1209178 — [RFC -v2 7/8] btrfs: Prevent from early transaction abort

FromMichal Hocko <mhocko@kernel.org>
Date2015-08-18 12:50 +0200
Subject[RFC -v2 7/8] btrfs: Prevent from early transaction abort
Message-ID<pYMCR-3Kd-11@gated-at.bofh.it>
In reply to#1200612
From: Michal Hocko <mhocko@suse.com>

Btrfs relies on GFP_NOFS allocation when commiting the transaction but
since "mm: page_alloc: do not lock up GFP_NOFS allocations upon OOM"
those allocations are allowed to fail which can lead to a pre-mature
transaction abort:

[   55.328093] Call Trace:
[   55.328890]  [<ffffffff8154e6f0>] dump_stack+0x4f/0x7b
[   55.330518]  [<ffffffff8108fa28>] ? console_unlock+0x334/0x363
[   55.332738]  [<ffffffff8110873e>] __alloc_pages_nodemask+0x81d/0x8d4
[   55.334910]  [<ffffffff81100752>] pagecache_get_page+0x10e/0x20c
[   55.336844]  [<ffffffffa007d916>] alloc_extent_buffer+0xd0/0x350 [btrfs]
[   55.338973]  [<ffffffffa0059d8c>] btrfs_find_create_tree_block+0x15/0x17 [btrfs]
[   55.341329]  [<ffffffffa004f728>] btrfs_alloc_tree_block+0x18c/0x405 [btrfs]
[   55.343566]  [<ffffffffa003fa34>] split_leaf+0x1e4/0x6a6 [btrfs]
[   55.345577]  [<ffffffffa0040567>] btrfs_search_slot+0x671/0x831 [btrfs]
[   55.347679]  [<ffffffff810682d7>] ? get_parent_ip+0xe/0x3e
[   55.349434]  [<ffffffffa0041cb2>] btrfs_insert_empty_items+0x5d/0xa8 [btrfs]
[   55.351681]  [<ffffffffa004ecfb>] __btrfs_run_delayed_refs+0x7a6/0xf35 [btrfs]
[   55.353979]  [<ffffffffa00512ea>] btrfs_run_delayed_refs+0x6e/0x226 [btrfs]
[   55.356212]  [<ffffffffa0060e21>] ? start_transaction+0x192/0x534 [btrfs]
[   55.358378]  [<ffffffffa0060e21>] ? start_transaction+0x192/0x534 [btrfs]
[   55.360626]  [<ffffffffa0060221>] btrfs_commit_transaction+0x4c/0xaba [btrfs]
[   55.362894]  [<ffffffffa0060e21>] ? start_transaction+0x192/0x534 [btrfs]
[   55.365221]  [<ffffffffa0073428>] btrfs_sync_file+0x29c/0x310 [btrfs]
[   55.367273]  [<ffffffff81186808>] vfs_fsync_range+0x8f/0x9e
[   55.369047]  [<ffffffff81186833>] vfs_fsync+0x1c/0x1e
[   55.370654]  [<ffffffff81186869>] do_fsync+0x34/0x4e
[   55.372246]  [<ffffffff81186ab3>] SyS_fsync+0x10/0x14
[   55.373851]  [<ffffffff81554f97>] system_call_fastpath+0x12/0x6f
[   55.381070] BTRFS: error (device hdb1) in btrfs_run_delayed_refs:2821: errno=-12 Out of memory
[   55.382431] BTRFS warning (device hdb1): Skipping commit of aborted transaction.
[   55.382433] BTRFS warning (device hdb1): cleanup_transaction:1692: Aborting unused transaction(IO failure).
[   55.384280] ------------[ cut here ]------------
[   55.384312] WARNING: CPU: 0 PID: 3010 at fs/btrfs/delayed-ref.c:438 btrfs_select_ref_head+0xd9/0xfe [btrfs]()
[...]
[   55.384337] Call Trace:
[   55.384353]  [<ffffffff8154e6f0>] dump_stack+0x4f/0x7b
[   55.384357]  [<ffffffff8107f717>] ? down_trylock+0x2d/0x37
[   55.384359]  [<ffffffff81046977>] warn_slowpath_common+0xa1/0xbb
[   55.384398]  [<ffffffffa00a1d6b>] ? btrfs_select_ref_head+0xd9/0xfe [btrfs]
[   55.384400]  [<ffffffff81046a34>] warn_slowpath_null+0x1a/0x1c
[   55.384423]  [<ffffffffa00a1d6b>] btrfs_select_ref_head+0xd9/0xfe [btrfs]
[   55.384446]  [<ffffffffa004e5f7>] ? __btrfs_run_delayed_refs+0xa2/0xf35 [btrfs]
[   55.384455]  [<ffffffffa004e600>] __btrfs_run_delayed_refs+0xab/0xf35 [btrfs]
[   55.384476]  [<ffffffffa00512ea>] btrfs_run_delayed_refs+0x6e/0x226 [btrfs]
[   55.384499]  [<ffffffffa0060e21>] ? start_transaction+0x192/0x534 [btrfs]
[   55.384521]  [<ffffffffa0060e21>] ? start_transaction+0x192/0x534 [btrfs]
[   55.384543]  [<ffffffffa0060221>] btrfs_commit_transaction+0x4c/0xaba [btrfs]
[   55.384565]  [<ffffffffa0060e21>] ? start_transaction+0x192/0x534 [btrfs]
[   55.384588]  [<ffffffffa0073428>] btrfs_sync_file+0x29c/0x310 [btrfs]
[   55.384591]  [<ffffffff81186808>] vfs_fsync_range+0x8f/0x9e
[   55.384592]  [<ffffffff81186833>] vfs_fsync+0x1c/0x1e
[   55.384593]  [<ffffffff81186869>] do_fsync+0x34/0x4e
[   55.384594]  [<ffffffff81186ab3>] SyS_fsync+0x10/0x14
[   55.384595]  [<ffffffff81554f97>] system_call_fastpath+0x12/0x6f
[...]
[   55.384608] ---[ end trace c29799da1d4dd621 ]---
[   55.437323] BTRFS info (device hdb1): forced readonly
[   55.438815] BTRFS info (device hdb1): delayed_refs has NO entry

Fix this by reintroducing the no-fail behavior of this allocation path
with the explicit __GFP_NOFAIL.

Signed-off-by: Michal Hocko <mhocko@suse.com>
---
 fs/btrfs/extent_io.c | 8 ++------
 1 file changed, 2 insertions(+), 6 deletions(-)

diff --git a/fs/btrfs/extent_io.c b/fs/btrfs/extent_io.c
index c374e1e71e5f..d855ddffd5fe 100644
--- a/fs/btrfs/extent_io.c
+++ b/fs/btrfs/extent_io.c
@@ -4607,9 +4607,7 @@ __alloc_extent_buffer(struct btrfs_fs_info *fs_info, u64 start,
 {
 	struct extent_buffer *eb = NULL;
 
-	eb = kmem_cache_zalloc(extent_buffer_cache, GFP_NOFS);
-	if (eb == NULL)
-		return NULL;
+	eb = kmem_cache_zalloc(extent_buffer_cache, GFP_NOFS|__GFP_NOFAIL);
 	eb->start = start;
 	eb->len = len;
 	eb->fs_info = fs_info;
@@ -4867,9 +4865,7 @@ struct extent_buffer *alloc_extent_buffer(struct btrfs_fs_info *fs_info,
 		return NULL;
 
 	for (i = 0; i < num_pages; i++, index++) {
-		p = find_or_create_page(mapping, index, GFP_NOFS);
-		if (!p)
-			goto free_eb;
+		p = find_or_create_page(mapping, index, GFP_NOFS|__GFP_NOFAIL);
 
 		spin_lock(&mapping->private_lock);
 		if (PagePrivate(p)) {
-- 
2.5.0

-- 
Michal Hocko
SUSE Labs
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#1209185 — Re: [RFC -v2 7/8] btrfs: Prevent from early transaction abort

FromMichal Hocko <mhocko@kernel.org>
Date2015-08-18 13:10 +0200
SubjectRe: [RFC -v2 7/8] btrfs: Prevent from early transaction abort
Message-ID<pYMWe-4m1-25@gated-at.bofh.it>
In reply to#1209178
On Tue 18-08-15 12:40:31, Michal Hocko wrote:
[...]
> @@ -4867,9 +4865,7 @@ struct extent_buffer *alloc_extent_buffer(struct btrfs_fs_info *fs_info,
>  		return NULL;
>  
>  	for (i = 0; i < num_pages; i++, index++) {
> -		p = find_or_create_page(mapping, index, GFP_NOFS);
> -		if (!p)
> -			goto free_eb;
> +		p = find_or_create_page(mapping, index, GFP_NOFS|__GFP_NOFAIL);
>  
>  		spin_lock(&mapping->private_lock);
>  		if (PagePrivate(p)) {

Same here. find_or_create_page might return NULL.
---
From f430e5f54367b8815e1099f26fedd2873b597a07 Mon Sep 17 00:00:00 2001
From: Michal Hocko <mhocko@suse.com>
Date: Wed, 15 Jul 2015 19:27:06 +0200
Subject: [PATCH] btrfs: Prevent from early transaction abort

Btrfs relies on GFP_NOFS allocation when commiting the transaction but
since "mm: page_alloc: do not lock up GFP_NOFS allocations upon OOM"
those allocations are allowed to fail which can lead to a pre-mature
transaction abort:

[   55.328093] Call Trace:
[   55.328890]  [<ffffffff8154e6f0>] dump_stack+0x4f/0x7b
[   55.330518]  [<ffffffff8108fa28>] ? console_unlock+0x334/0x363
[   55.332738]  [<ffffffff8110873e>] __alloc_pages_nodemask+0x81d/0x8d4
[   55.334910]  [<ffffffff81100752>] pagecache_get_page+0x10e/0x20c
[   55.336844]  [<ffffffffa007d916>] alloc_extent_buffer+0xd0/0x350 [btrfs]
[   55.338973]  [<ffffffffa0059d8c>] btrfs_find_create_tree_block+0x15/0x17 [btrfs]
[   55.341329]  [<ffffffffa004f728>] btrfs_alloc_tree_block+0x18c/0x405 [btrfs]
[   55.343566]  [<ffffffffa003fa34>] split_leaf+0x1e4/0x6a6 [btrfs]
[   55.345577]  [<ffffffffa0040567>] btrfs_search_slot+0x671/0x831 [btrfs]
[   55.347679]  [<ffffffff810682d7>] ? get_parent_ip+0xe/0x3e
[   55.349434]  [<ffffffffa0041cb2>] btrfs_insert_empty_items+0x5d/0xa8 [btrfs]
[   55.351681]  [<ffffffffa004ecfb>] __btrfs_run_delayed_refs+0x7a6/0xf35 [btrfs]
[   55.353979]  [<ffffffffa00512ea>] btrfs_run_delayed_refs+0x6e/0x226 [btrfs]
[   55.356212]  [<ffffffffa0060e21>] ? start_transaction+0x192/0x534 [btrfs]
[   55.358378]  [<ffffffffa0060e21>] ? start_transaction+0x192/0x534 [btrfs]
[   55.360626]  [<ffffffffa0060221>] btrfs_commit_transaction+0x4c/0xaba [btrfs]
[   55.362894]  [<ffffffffa0060e21>] ? start_transaction+0x192/0x534 [btrfs]
[   55.365221]  [<ffffffffa0073428>] btrfs_sync_file+0x29c/0x310 [btrfs]
[   55.367273]  [<ffffffff81186808>] vfs_fsync_range+0x8f/0x9e
[   55.369047]  [<ffffffff81186833>] vfs_fsync+0x1c/0x1e
[   55.370654]  [<ffffffff81186869>] do_fsync+0x34/0x4e
[   55.372246]  [<ffffffff81186ab3>] SyS_fsync+0x10/0x14
[   55.373851]  [<ffffffff81554f97>] system_call_fastpath+0x12/0x6f
[   55.381070] BTRFS: error (device hdb1) in btrfs_run_delayed_refs:2821: errno=-12 Out of memory
[   55.382431] BTRFS warning (device hdb1): Skipping commit of aborted transaction.
[   55.382433] BTRFS warning (device hdb1): cleanup_transaction:1692: Aborting unused transaction(IO failure).
[   55.384280] ------------[ cut here ]------------
[   55.384312] WARNING: CPU: 0 PID: 3010 at fs/btrfs/delayed-ref.c:438 btrfs_select_ref_head+0xd9/0xfe [btrfs]()
[...]
[   55.384337] Call Trace:
[   55.384353]  [<ffffffff8154e6f0>] dump_stack+0x4f/0x7b
[   55.384357]  [<ffffffff8107f717>] ? down_trylock+0x2d/0x37
[   55.384359]  [<ffffffff81046977>] warn_slowpath_common+0xa1/0xbb
[   55.384398]  [<ffffffffa00a1d6b>] ? btrfs_select_ref_head+0xd9/0xfe [btrfs]
[   55.384400]  [<ffffffff81046a34>] warn_slowpath_null+0x1a/0x1c
[   55.384423]  [<ffffffffa00a1d6b>] btrfs_select_ref_head+0xd9/0xfe [btrfs]
[   55.384446]  [<ffffffffa004e5f7>] ? __btrfs_run_delayed_refs+0xa2/0xf35 [btrfs]
[   55.384455]  [<ffffffffa004e600>] __btrfs_run_delayed_refs+0xab/0xf35 [btrfs]
[   55.384476]  [<ffffffffa00512ea>] btrfs_run_delayed_refs+0x6e/0x226 [btrfs]
[   55.384499]  [<ffffffffa0060e21>] ? start_transaction+0x192/0x534 [btrfs]
[   55.384521]  [<ffffffffa0060e21>] ? start_transaction+0x192/0x534 [btrfs]
[   55.384543]  [<ffffffffa0060221>] btrfs_commit_transaction+0x4c/0xaba [btrfs]
[   55.384565]  [<ffffffffa0060e21>] ? start_transaction+0x192/0x534 [btrfs]
[   55.384588]  [<ffffffffa0073428>] btrfs_sync_file+0x29c/0x310 [btrfs]
[   55.384591]  [<ffffffff81186808>] vfs_fsync_range+0x8f/0x9e
[   55.384592]  [<ffffffff81186833>] vfs_fsync+0x1c/0x1e
[   55.384593]  [<ffffffff81186869>] do_fsync+0x34/0x4e
[   55.384594]  [<ffffffff81186ab3>] SyS_fsync+0x10/0x14
[   55.384595]  [<ffffffff81554f97>] system_call_fastpath+0x12/0x6f
[...]
[   55.384608] ---[ end trace c29799da1d4dd621 ]---
[   55.437323] BTRFS info (device hdb1): forced readonly
[   55.438815] BTRFS info (device hdb1): delayed_refs has NO entry

Fix this by reintroducing the no-fail behavior of this allocation path
with the explicit __GFP_NOFAIL.

Signed-off-by: Michal Hocko <mhocko@suse.com>
---
 fs/btrfs/extent_io.c | 6 ++----
 1 file changed, 2 insertions(+), 4 deletions(-)

diff --git a/fs/btrfs/extent_io.c b/fs/btrfs/extent_io.c
index c374e1e71e5f..f4d6eea975d7 100644
--- a/fs/btrfs/extent_io.c
+++ b/fs/btrfs/extent_io.c
@@ -4607,9 +4607,7 @@ __alloc_extent_buffer(struct btrfs_fs_info *fs_info, u64 start,
 {
 	struct extent_buffer *eb = NULL;
 
-	eb = kmem_cache_zalloc(extent_buffer_cache, GFP_NOFS);
-	if (eb == NULL)
-		return NULL;
+	eb = kmem_cache_zalloc(extent_buffer_cache, GFP_NOFS|__GFP_NOFAIL);
 	eb->start = start;
 	eb->len = len;
 	eb->fs_info = fs_info;
@@ -4867,7 +4865,7 @@ struct extent_buffer *alloc_extent_buffer(struct btrfs_fs_info *fs_info,
 		return NULL;
 
 	for (i = 0; i < num_pages; i++, index++) {
-		p = find_or_create_page(mapping, index, GFP_NOFS);
+		p = find_or_create_page(mapping, index, GFP_NOFS|__GFP_NOFAIL);
 		if (!p)
 			goto free_eb;
 
-- 
2.5.0

-- 
Michal Hocko
SUSE Labs
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#1209395 — Re: [RFC -v2 7/8] btrfs: Prevent from early transaction abort

FromChris Mason <clm@fb.com>
Date2015-08-18 19:20 +0200
SubjectRe: [RFC -v2 7/8] btrfs: Prevent from early transaction abort
Message-ID<pYSIi-4kl-29@gated-at.bofh.it>
In reply to#1209178
On Tue, Aug 18, 2015 at 12:40:32PM +0200, Michal Hocko wrote:
> From: Michal Hocko <mhocko@suse.com>
> 
> Btrfs relies on GFP_NOFS allocation when commiting the transaction but
> since "mm: page_alloc: do not lock up GFP_NOFS allocations upon OOM"
> those allocations are allowed to fail which can lead to a pre-mature
> transaction abort:

I can either put the btrfs nofail ones on my pull for Linus, or you can
add my sob and send as one unit.  Just let me know how you'd rather do
it.

-chris
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#1209402 — Re: [RFC -v2 7/8] btrfs: Prevent from early transaction abort

FromMichal Hocko <mhocko@kernel.org>
Date2015-08-18 19:30 +0200
SubjectRe: [RFC -v2 7/8] btrfs: Prevent from early transaction abort
Message-ID<pYSRX-4vO-9@gated-at.bofh.it>
In reply to#1209395
On Tue 18-08-15 13:11:44, Chris Mason wrote:
> On Tue, Aug 18, 2015 at 12:40:32PM +0200, Michal Hocko wrote:
> > From: Michal Hocko <mhocko@suse.com>
> > 
> > Btrfs relies on GFP_NOFS allocation when commiting the transaction but
> > since "mm: page_alloc: do not lock up GFP_NOFS allocations upon OOM"
> > those allocations are allowed to fail which can lead to a pre-mature
> > transaction abort:
> 
> I can either put the btrfs nofail ones on my pull for Linus, or you can
> add my sob and send as one unit.  Just let me know how you'd rather do
> it.

OK, I will rephrase the changelogs (tomorrow) to not refer to an
unmerged patch and would appreciate if you can take them and route them
through your tree. I will then drop them from my pile.

Thanks.
-- 
Michal Hocko
SUSE Labs
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#1209813 — Re: [RFC -v2 7/8] btrfs: Prevent from early transaction abort

FromMichal Hocko <mhocko@kernel.org>
Date2015-08-19 14:30 +0200
SubjectRe: [RFC -v2 7/8] btrfs: Prevent from early transaction abort
Message-ID<pZaFb-5Oe-5@gated-at.bofh.it>
In reply to#1209402
On Tue 18-08-15 19:29:14, Michal Hocko wrote:
> On Tue 18-08-15 13:11:44, Chris Mason wrote:
> > On Tue, Aug 18, 2015 at 12:40:32PM +0200, Michal Hocko wrote:
> > > From: Michal Hocko <mhocko@suse.com>
> > > 
> > > Btrfs relies on GFP_NOFS allocation when commiting the transaction but
> > > since "mm: page_alloc: do not lock up GFP_NOFS allocations upon OOM"
> > > those allocations are allowed to fail which can lead to a pre-mature
> > > transaction abort:
> > 
> > I can either put the btrfs nofail ones on my pull for Linus, or you can
> > add my sob and send as one unit.  Just let me know how you'd rather do
> > it.
> 
> OK, I will rephrase the changelogs (tomorrow) to not refer to an
> unmerged patch and would appreciate if you can take them and route them
> through your tree. I will then drop them from my pile.

Poste in a separate thread
http://lkml.kernel.org/r/1439986661-15896-1-git-send-email-mhocko@kernel.org
-- 
Michal Hocko
SUSE Labs
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