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Commit 827aa18e authored by Filipe Manana's avatar Filipe Manana Committed by David Sterba
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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: 39a27ec1 ("btrfs: use GFP_KERNEL for xattr and acl allocations")
Reviewed-by: default avatarNikolay Borisov <nborisov@suse.com>
Signed-off-by: default avatarFilipe Manana <fdmanana@suse.com>
Reviewed-by: default avatarDavid Sterba <dsterba@suse.com>
Signed-off-by: default avatarDavid Sterba <dsterba@suse.com>
parent 0568e82d

fs/btrfs/xattr.c

+8 −0
Original line number Diff line number Diff line
@@ -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;

}