On 7/8/21 9:09 PM, Darrick J. Wong wrote:

On Wed, Jul 07, 2021 at 03:21:02PM -0700, Allison Henderson wrote:

quoted

Because xattrs can be over a page in size, we need to handle possible
krealloc errors to avoid warnings.  If the allocation does fail, fall
back to kmem_alloc_large, with a memcpy.

The warning:
    WARNING: CPU: 1 PID: 20255 at mm/page_alloc.c:3446
                  get_page_from_freelist+0x100b/0x1690

is caused when sizes larger that a page are allocated with the
__GFP_NOFAIL flag option.  We encounter this error now because attr
values can be up to 64k in size.  So we cannot use __GFP_NOFAIL, and
we need to handle the error code if the allocation fails.

Signed-off-by: Allison Henderson <redacted>

I'm pretty sure that 'mm: Add kvrealloc' fixes this a little more
elegantly, but either look fine to me.  So while I'll probably take
Dave's, here's a:

Reviewed-by: Darrick J. Wong <djwong@kernel.org>

in the meantime.

Alrighty, thank you!  Either is fine.

Allison

--D

quoted

---
  fs/xfs/xfs_log_recover.c | 10 +++++++++-
  1 file changed, 9 insertions(+), 1 deletion(-)

diff --git a/fs/xfs/xfs_log_recover.c b/fs/xfs/xfs_log_recover.c
index ec4ccae..6ab467b 100644
--- a/fs/xfs/xfs_log_recover.c
+++ b/fs/xfs/xfs_log_recover.c

@@ -2062,7 +2062,15 @@ xlog_recover_add_to_cont_trans(
  	old_ptr = item->ri_buf[item->ri_cnt-1].i_addr;
  	old_len = item->ri_buf[item->ri_cnt-1].i_len;
  
-	ptr = krealloc(old_ptr, len + old_len, GFP_KERNEL | __GFP_NOFAIL);
+	ptr = krealloc(old_ptr, len + old_len, GFP_KERNEL);
+	if (ptr == NULL) {
+		ptr = kmem_alloc_large(len + old_len, KM_ZERO);
+		if (ptr == NULL)
+			return -ENOMEM;
+
+		memcpy(ptr, old_ptr, old_len);
+	}
+
  	memcpy(&ptr[old_len], dp, len);
  	item->ri_buf[item->ri_cnt-1].i_len += len;
  	item->ri_buf[item->ri_cnt-1].i_addr = ptr;

-- 
2.7.4