Re: [PATCH v5 1/2] erofs: avoid memory allocation failure during rolling decompression

[Chao Yu]

On 2021/3/5 17:58, Huang Jianan via Linux-erofs wrote:

Currently, err would be treated as io error. Therefore, it'd be
better to ensure memory allocation during rolling decompression
to avoid such io error.

In the long term, we might consider adding another !Uptodate case
for such case.

Signed-off-by: Huang Jianan <huangjia...@oppo.com>
Signed-off-by: Guo Weichao <guoweic...@oppo.com>
---
  fs/erofs/decompressor.c | 3 ++-
  1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/fs/erofs/decompressor.c b/fs/erofs/decompressor.c
index 1cb1ffd10569..3d276a8aad86 100644
--- a/fs/erofs/decompressor.c
+++ b/fs/erofs/decompressor.c
@@ -73,7 +73,8 @@ static int z_erofs_lz4_prepare_destpages(struct 
z_erofs_decompress_req *rq,
                        victim = availables[--top];
                        get_page(victim);
                } else {
-                       victim = erofs_allocpage(pagepool, GFP_KERNEL);
+                       victim = erofs_allocpage(pagepool,
+                                                GFP_KERNEL | __GFP_NOFAIL);
                        if (!victim)
                                return -ENOMEM;

A little bit weird that we still need to check return value of erofs_allocpage()
after we pass __GFP_NOFAIL parameter.

Thanks,

                        set_page_private(victim, Z_EROFS_SHORTLIVED_PAGE);