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Btrfs: use nofs context when initializing security xattrs to avoid deadlock 

When initializing the security xattrs, we are holding a transaction handle
therefore we need to use a GFP_NOFS context in order to avoid a deadlock
with reclaim in case it's triggered.

Fixes: 39a27ec100 ("btrfs: use GFP_KERNEL for xattr and acl allocations")
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>
hifive-unleashed-5.1
Filipe Manana 2018-12-10 17:53:35 +00:00 committed by David Sterba
parent 0568e82dbe
commit 827aa18e7b
1 changed files with 8 additions and 0 deletions
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8
fs/btrfs/xattr.c
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@ -11,6 +11,7 @@
#include <linux/security.h>
#include <linux/posix_acl_xattr.h>
#include <linux/iversion.h>
#include <linux/sched/mm.h>
#include "ctree.h"
#include "btrfs_inode.h"
#include "transaction.h"
@ -422,9 +423,15 @@ static int btrfs_initxattrs(struct inode *inode,
{
const struct xattr *xattr;
struct btrfs_trans_handle *trans = fs_info;
unsigned int nofs_flag;
char *name;
int err = 0;
/*
* We're holding a transaction handle, so use a NOFS memory allocation
* context to avoid deadlock if reclaim happens.
*/
nofs_flag = memalloc_nofs_save();
for (xattr = xattr_array; xattr->name != NULL; xattr++) {
name = kmalloc(XATTR_SECURITY_PREFIX_LEN +
strlen(xattr->name) + 1, GFP_KERNEL);
@ -440,6 +447,7 @@ static int btrfs_initxattrs(struct inode *inode,
if (err < 0)
break;
}
memalloc_nofs_restore(nofs_flag);
return err;
}