| From | Greg Kroah-Hartman <> | Subject | [PATCH 4.14 102/183] Btrfs: setup a nofs context for memory allocation at __btrfs_set_acl | Date | Fri, 22 Mar 2019 12:15:30 +0100 |
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4.14-stable review patch. If anyone has any objections, please let me know.
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From: Filipe Manana <fdmanana@suse.com>
commit a0873490660246db587849a9e172f2b7b21fa88a upstream.
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: 39a27ec1004e8 ("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> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
--- fs/btrfs/acl.c | 9 +++++++++ 1 file changed, 9 insertions(+)
--- a/fs/btrfs/acl.c +++ b/fs/btrfs/acl.c @@ -22,6 +22,7 @@ #include <linux/posix_acl_xattr.h> #include <linux/posix_acl.h> #include <linux/sched.h> +#include <linux/sched/mm.h> #include <linux/slab.h> #include "ctree.h" @@ -89,8 +90,16 @@ static int __btrfs_set_acl(struct btrfs_ } if (acl) { + unsigned int nofs_flag; + 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); + memalloc_nofs_restore(nofs_flag); if (!value) { ret = -ENOMEM; goto out;
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