[PATCH 03/10] xfs: fallback to vmalloc for large buffers in xfs_attrmulti_attr_get

Dave Chinner
2012-03-07T04:50:37Z

From: Dave Chinner <dchinner@redhat.com>

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: Dave Chinner <dchinner@redhat.com>
---
fs/xfs/xfs_ioctl.c | 14 ++++++++++----
1 files changed, 10 insertions(+), 4 deletions(-)

diff --git a/fs/xfs/xfs_ioctl.c b/fs/xfs/xfs_ioctl.c
index 8dc5fe1..91f8ff5 100644
--- a/fs/xfs/xfs_ioctl.c
+++ b/fs/xfs/xfs_ioctl.c
@@ -446,9 +446,12 @@ xfs_attrmulti_attr_get(

if (*len > XATTR_SIZE_MAX)
return EINVAL;
- kbuf = kmalloc(*len, GFP_KERNEL);
- if (!kbuf)
- return ENOMEM;
+ kbuf = kmem_zalloc(*len, KM_SLEEP | KM_MAYFAIL);
+ if (!kbuf) {
+ kbuf = kmem_zalloc_large(*len);
+ if (!kbuf)
+ return ENOMEM;
+ }

error = xfs_attr_get(XFS_I(inode), name, kbuf, (int *)len, flags);
if (error)
@@ -458,7 +461,10 @@ xfs_attrmulti_attr_get(
error = EFAULT;

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

--
1.7.9