Re: [f2fs-dev] [PATCH v2] f2fs: don't use GFP_ZERO for page caches

From: Jaegeuk Kim
Date: Mon Apr 09 2018 - 21:35:54 EST


On 04/09, Jaegeuk Kim wrote:
> Change log from v1:
> - don't memset for recovered page
>
> Related to https://lkml.org/lkml/2018/4/8/661
>
> Sometimes, we need to write meta data to new allocated block address,
> then we will allocate a zeroed page in inner inode's address space, and
> fill partial data in it, and leave other place with zero value which means
> some fields are initial status.
>
> There are two inner inodes (meta inode and node inode) setting __GFP_ZERO,
> I have just checked them, for both of them, we can avoid using __GFP_ZERO,
> and do initialization by ourselves to avoid unneeded/redundant zeroing
> from mm.

Okay, it seems we're missing some more places to reset the memory, since
I'm still getting a panic. :(

Thanks,

>
> Cc: <stable@xxxxxxxxxxxxxxx>
> Signed-off-by: Chao Yu <yuchao0@xxxxxxxxxx>
> Signed-off-by: Jaegeuk Kim <jaegeuk@xxxxxxxxxx>
> ---
> fs/f2fs/inode.c | 4 ++--
> fs/f2fs/node.c | 3 ++-
> 2 files changed, 4 insertions(+), 3 deletions(-)
>
> diff --git a/fs/f2fs/inode.c b/fs/f2fs/inode.c
> index 417c9dcd0269..87535bf63421 100644
> --- a/fs/f2fs/inode.c
> +++ b/fs/f2fs/inode.c
> @@ -320,10 +320,10 @@ struct inode *f2fs_iget(struct super_block *sb, unsigned long ino)
> make_now:
> if (ino == F2FS_NODE_INO(sbi)) {
> inode->i_mapping->a_ops = &f2fs_node_aops;
> - mapping_set_gfp_mask(inode->i_mapping, GFP_F2FS_ZERO);
> + mapping_set_gfp_mask(inode->i_mapping, GFP_NOFS);
> } else if (ino == F2FS_META_INO(sbi)) {
> inode->i_mapping->a_ops = &f2fs_meta_aops;
> - mapping_set_gfp_mask(inode->i_mapping, GFP_F2FS_ZERO);
> + mapping_set_gfp_mask(inode->i_mapping, GFP_NOFS);
> } else if (S_ISREG(inode->i_mode)) {
> inode->i_op = &f2fs_file_inode_operations;
> inode->i_fop = &f2fs_file_operations;
> diff --git a/fs/f2fs/node.c b/fs/f2fs/node.c
> index 9a99243054ba..5a4469093e43 100644
> --- a/fs/f2fs/node.c
> +++ b/fs/f2fs/node.c
> @@ -1096,7 +1096,8 @@ struct page *new_node_page(struct dnode_of_data *dn, unsigned int ofs)
> set_node_addr(sbi, &new_ni, NEW_ADDR, false);
>
> f2fs_wait_on_page_writeback(page, NODE, true);
> - fill_node_footer(page, dn->nid, dn->inode->i_ino, ofs, true);
> + memset(F2FS_NODE(page), 0, PAGE_SIZE);
> + fill_node_footer(page, dn->nid, dn->inode->i_ino, ofs, false);
> set_cold_node(page, S_ISDIR(dn->inode->i_mode));
> if (!PageUptodate(page))
> SetPageUptodate(page);
> --
> 2.15.0.531.g2ccb3012c9-goog
>
>
> ------------------------------------------------------------------------------
> Check out the vibrant tech community on one of the world's most
> engaging tech sites, Slashdot.org! http://sdm.link/slashdot
> _______________________________________________
> Linux-f2fs-devel mailing list
> Linux-f2fs-devel@xxxxxxxxxxxxxxxxxxxxx
> https://lists.sourceforge.net/lists/listinfo/linux-f2fs-devel