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Commit | Line | Data |
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2705b78f GKH |
1 | From a0873490660246db587849a9e172f2b7b21fa88a Mon Sep 17 00:00:00 2001 |
2 | From: Filipe Manana <fdmanana@suse.com> | |
3 | Date: Thu, 13 Dec 2018 21:16:56 +0000 | |
4 | Subject: Btrfs: setup a nofs context for memory allocation at __btrfs_set_acl | |
5 | ||
6 | From: Filipe Manana <fdmanana@suse.com> | |
7 | ||
8 | commit a0873490660246db587849a9e172f2b7b21fa88a upstream. | |
9 | ||
10 | We are holding a transaction handle when setting an acl, therefore we can | |
11 | not allocate the xattr value buffer using GFP_KERNEL, as we could deadlock | |
12 | if reclaim is triggered by the allocation, therefore setup a nofs context. | |
13 | ||
14 | Fixes: 39a27ec1004e8 ("btrfs: use GFP_KERNEL for xattr and acl allocations") | |
15 | CC: stable@vger.kernel.org # 4.9+ | |
16 | Reviewed-by: Nikolay Borisov <nborisov@suse.com> | |
17 | Signed-off-by: Filipe Manana <fdmanana@suse.com> | |
18 | Reviewed-by: David Sterba <dsterba@suse.com> | |
19 | Signed-off-by: David Sterba <dsterba@suse.com> | |
20 | Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> | |
21 | ||
22 | --- | |
23 | fs/btrfs/acl.c | 9 +++++++++ | |
24 | 1 file changed, 9 insertions(+) | |
25 | ||
26 | --- a/fs/btrfs/acl.c | |
27 | +++ b/fs/btrfs/acl.c | |
28 | @@ -22,6 +22,7 @@ | |
29 | #include <linux/posix_acl_xattr.h> | |
30 | #include <linux/posix_acl.h> | |
31 | #include <linux/sched.h> | |
32 | +#include <linux/sched/mm.h> | |
33 | #include <linux/slab.h> | |
34 | ||
35 | #include "ctree.h" | |
36 | @@ -89,8 +90,16 @@ static int __btrfs_set_acl(struct btrfs_ | |
37 | } | |
38 | ||
39 | if (acl) { | |
40 | + unsigned int nofs_flag; | |
41 | + | |
42 | size = posix_acl_xattr_size(acl->a_count); | |
43 | + /* | |
44 | + * We're holding a transaction handle, so use a NOFS memory | |
45 | + * allocation context to avoid deadlock if reclaim happens. | |
46 | + */ | |
47 | + nofs_flag = memalloc_nofs_save(); | |
48 | value = kmalloc(size, GFP_KERNEL); | |
49 | + memalloc_nofs_restore(nofs_flag); | |
50 | if (!value) { | |
51 | ret = -ENOMEM; | |
52 | goto out; |