Btrfs: use nofs context when initializing security xattrs to avoid deadlock (827aa18e) · Commits · 戴 / test

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: ("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>

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;
		}

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