[PATCH] xfs: xfs: fallback to vmalloc for large buffers in xfs_attrlist_by_handle

Eric Sandeen
2013-04-04T05:05:19Z

On 4/3/13 10:52 PM, Dave Chinner wrote:
> On Wed, Apr 03, 2013 at 03:52:49PM -0700, Linda Walsh wrote:
>>
>> Note -- I might have more attributes than some as the disks are shared via samba
>> w/windows
>> and samba stores ACL and xattr info from windows in xfs's attrs...
>>
>>
>> xfsdump: WARNING: could not get list of root attributes for nondir ino
>> 3412893285: Cannot allocate memory (12)
>
> ....
>> [1007383.689492] xfsdump: page allocation failure: order:4, mode:0x10c0d0
> ....
>> [1007383.689531] [<ffffffff81143a54>] kmalloc_order_trace+0x34/0xe0
>> [1007383.689534] [<ffffffff81146546>] __kmalloc+0x186/0x190
>> [1007383.689541] [<ffffffff8124263c>] xfs_attrlist_by_handle+0x8c/0x110
>> [1007383.689544] [<ffffffff81243487>] xfs_file_ioctl+0x437/0xb60
>
> So it's the attribute handle interfaces that need the vmalloc
> treatment here, just like has been done for all the other attribute
> interfaces....

Like this?

From: Eric Sandeen <sandeen@redhat.com>

xfs: fallback to vmalloc for large buffers in xfs_attrlist_by_handle

Shamelessly copied from dchinner's:
ad650f5b xfs: fallback to vmalloc for large buffers in xfs_attrmulti_attr_get

xfsdump uses for a large buffer for extended attributes, which has a
kmalloc'd shadow buffer in the kernel. This can fail after the
system has been running for some time as it is a high order
allocation. Add a fallback to vmalloc so that it doesn't require
contiguous memory and so won't randomly fail while xfsdump is
running.

Signed-off-by: Eric Sandeen <sandeen@redhat.com>
---

built & tested by running through xfstests ./check -g dump

diff --git a/fs/xfs/xfs_ioctl.c b/fs/xfs/xfs_ioctl.c
index d681e34..5e99968 100644
--- a/fs/xfs/xfs_ioctl.c
+++ b/fs/xfs/xfs_ioctl.c
@@ -422,9 +422,12 @@ xfs_attrlist_by_handle(
if (IS_ERR(dentry))
return PTR_ERR(dentry);

- kbuf = kzalloc(al_hreq.buflen, GFP_KERNEL);
- if (!kbuf)
- goto out_dput;
+ kbuf = kmem_zalloc(al_hreq.buflen, KM_SLEEP | KM_MAYFAIL);
+ if (!kbuf) {
+ kbuf = kmem_zalloc_large(al_hreq.buflen);
+ if (!kbuf)
+ goto out_dput;
+ }

cursor = (attrlist_cursor_kern_t *)&al_hreq.pos;
error = -xfs_attr_list(XFS_I(dentry->d_inode), kbuf, al_hreq.buflen,
@@ -436,7 +439,10 @@ xfs_attrlist_by_handle(
error = -EFAULT;

out_kfree:
- kfree(kbuf);
+ if (is_vmalloc_addr(kbuf))
+ kmem_free_large(kbuf);
+ else
+ kmem_free(kbuf);
out_dput:
dput(dentry);
return error;