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: Dave Chinner <dchinner@redhat.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Mark Tinguely <tinguely@sgi.com>
Signed-off-by: Ben Myers <bpm@sgi.com>

1 files changed, 10 insertions, 4 deletions

diff --git a/fs/xfs/xfs_ioctl.c b/fs/xfs/xfs_ioctl.c
index 76f3ca5cfc36..f588320dc4b9 100644
--- a/fs/xfs/xfs_ioctl.c
+++ b/fs/xfs/xfs_ioctl.c
@@ -450,9 +450,12 @@ 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)
@@ -462,7 +465,10 @@ 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;
 }