* [PATCH] Btrfs: setup a nofs context for memory allocation at __btrfs_set_acl
@ 2018-12-13 21:16 fdmanana
2018-12-14 7:28 ` Nikolay Borisov
2019-01-03 17:01 ` David Sterba
0 siblings, 2 replies; 3+ messages in thread
From: fdmanana @ 2018-12-13 21:16 UTC (permalink / raw)
To: linux-btrfs
From: Filipe Manana <fdmanana@suse.com>
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")
Signed-off-by: Filipe Manana <fdmanana@suse.com>
---
fs/btrfs/acl.c | 9 +++++++++
1 file changed, 9 insertions(+)
diff --git a/fs/btrfs/acl.c b/fs/btrfs/acl.c
index 3b66c957ea6f..5810463dc6d2 100644
--- a/fs/btrfs/acl.c
+++ b/fs/btrfs/acl.c
@@ -9,6 +9,7 @@
#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"
@@ -72,8 +73,16 @@ static int __btrfs_set_acl(struct btrfs_trans_handle *trans,
}
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;
--
2.11.0
^ permalink raw reply related [flat|nested] 3+ messages in thread
* Re: [PATCH] Btrfs: setup a nofs context for memory allocation at __btrfs_set_acl
2018-12-13 21:16 [PATCH] Btrfs: setup a nofs context for memory allocation at __btrfs_set_acl fdmanana
@ 2018-12-14 7:28 ` Nikolay Borisov
2019-01-03 17:01 ` David Sterba
1 sibling, 0 replies; 3+ messages in thread
From: Nikolay Borisov @ 2018-12-14 7:28 UTC (permalink / raw)
To: fdmanana, linux-btrfs
On 13.12.18 г. 23:16 ч., fdmanana@kernel.org wrote:
> From: Filipe Manana <fdmanana@suse.com>
>
> 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")
> Signed-off-by: Filipe Manana <fdmanana@suse.com>
Reviewed-by: Nikolay Borisov <nborisov@suse.com>
> ---
> fs/btrfs/acl.c | 9 +++++++++
> 1 file changed, 9 insertions(+)
>
> diff --git a/fs/btrfs/acl.c b/fs/btrfs/acl.c
> index 3b66c957ea6f..5810463dc6d2 100644
> --- a/fs/btrfs/acl.c
> +++ b/fs/btrfs/acl.c
> @@ -9,6 +9,7 @@
> #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"
> @@ -72,8 +73,16 @@ static int __btrfs_set_acl(struct btrfs_trans_handle *trans,
> }
>
> 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;
>
^ permalink raw reply [flat|nested] 3+ messages in thread
* Re: [PATCH] Btrfs: setup a nofs context for memory allocation at __btrfs_set_acl
2018-12-13 21:16 [PATCH] Btrfs: setup a nofs context for memory allocation at __btrfs_set_acl fdmanana
2018-12-14 7:28 ` Nikolay Borisov
@ 2019-01-03 17:01 ` David Sterba
1 sibling, 0 replies; 3+ messages in thread
From: David Sterba @ 2019-01-03 17:01 UTC (permalink / raw)
To: fdmanana; +Cc: linux-btrfs
On Thu, Dec 13, 2018 at 09:16:56PM +0000, fdmanana@kernel.org wrote:
> From: Filipe Manana <fdmanana@suse.com>
>
> 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")
> Signed-off-by: Filipe Manana <fdmanana@suse.com>
Added to misc-next, thanks.
^ permalink raw reply [flat|nested] 3+ messages in thread
end of thread, other threads:[~2019-01-03 17:02 UTC | newest]
Thread overview: 3+ messages (download: mbox.gz / follow: Atom feed)
-- links below jump to the message on this page --
2018-12-13 21:16 [PATCH] Btrfs: setup a nofs context for memory allocation at __btrfs_set_acl fdmanana
2018-12-14 7:28 ` Nikolay Borisov
2019-01-03 17:01 ` David Sterba
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox;
as well as URLs for NNTP newsgroup(s).