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Btrfs: setup a nofs context for memory allocation at __btrfs_set_acl

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We are holding a transaction handle when setting an acl, therefore we can
not allocate the xattr value buffer using GFP_KERNEL, as we could deadlock
if reclaim is triggered by the allocation, therefore setup a nofs context.

Fixes: 39a27ec100 ("btrfs: use GFP_KERNEL for xattr and acl allocations")
CC: stable@vger.kernel.org # 4.9+
Reviewed-by: Nikolay Borisov <nborisov@suse.com>
Signed-off-by: Filipe Manana <fdmanana@suse.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
This commit is contained in:
Filipe Manana 2018-12-13 21:16:56 +00:00 committed by David Sterba
parent b89f6d1fcb
commit a087349066
1 changed files with 9 additions and 0 deletions
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9
fs/btrfs/acl.c
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@ -9,6 +9,7 @@
#include <linux/posix_acl_xattr.h> #include <linux/posix_acl_xattr.h>
#include <linux/posix_acl.h> #include <linux/posix_acl.h>
#include <linux/sched.h> #include <linux/sched.h>
#include <linux/sched/mm.h>
#include <linux/slab.h> #include <linux/slab.h>
#include "ctree.h" #include "ctree.h"
@ -72,8 +73,16 @@ static int __btrfs_set_acl(struct btrfs_trans_handle *trans,
} }
if (acl) { if (acl) {
unsigned int nofs_flag;
size = posix_acl_xattr_size(acl->a_count); size = posix_acl_xattr_size(acl->a_count);
/*
* We're holding a transaction handle, so use a NOFS memory
* allocation context to avoid deadlock if reclaim happens.
*/
nofs_flag = memalloc_nofs_save();
value = kmalloc(size, GFP_KERNEL); value = kmalloc(size, GFP_KERNEL);
memalloc_nofs_restore(nofs_flag);
if (!value) { if (!value) {
ret = -ENOMEM; ret = -ENOMEM;
goto out; goto out;