4.20-stable review patch. If anyone has any objections, please let me know.
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From: Filipe Manana fdmanana@suse.com
commit 827aa18e7b903c5ff3b3cd8fec328a99b1dbd411 upstream.
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: 39a27ec1004e8 ("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 Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org
--- fs/btrfs/xattr.c | 8 ++++++++ 1 file changed, 8 insertions(+)
--- a/fs/btrfs/xattr.c +++ b/fs/btrfs/xattr.c @@ -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 { 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 if (err < 0) break; } + memalloc_nofs_restore(nofs_flag); return err; }