Commit 2f0407ed authored by Gao Xiang's avatar Gao Xiang
Browse files

erofs: fix .fadvise() for page cache sharing 



Currently, .fadvise() doesn't work well if page cache sharing is on
since shared inodes belong to a pseudo fs generated with init_pseudo(),
and sb->s_bdi is the default one &noop_backing_dev_info.

Then, generic_fadvise() will just behave as a no-op if sb->s_bdi is
&noop_backing_dev_info, but as the bdev fs (the bdev fs changes
inode_to_bdi() instead), it's actually NOT a pure memfs.

Let's generate a real bdi for erofs_ishare_mnt instead.

Fixes: d86d7817 ("erofs: implement .fadvise for page cache share")
Reviewed-by: default avatarHongbo Li <lihongbo22@huawei.com>
Signed-off-by: default avatarGao Xiang <hsiangkao@linux.alibaba.com>
parent 938c4184

fs/erofs/ishare.c

+13 −2
Original line number Diff line number Diff line
@@ -200,8 +200,19 @@ struct inode *erofs_real_inode(struct inode *inode, bool *need_iput) 


int __init erofs_init_ishare(void)

{

	erofs_ishare_mnt = kern_mount(&erofs_anon_fs_type);

	return PTR_ERR_OR_ZERO(erofs_ishare_mnt);

	struct vfsmount *mnt;

	int ret;



	mnt = kern_mount(&erofs_anon_fs_type);

	if (IS_ERR(mnt))

		return PTR_ERR(mnt);

	/* generic_fadvise() doesn't work if s_bdi == &noop_backing_dev_info */

	ret = super_setup_bdi(mnt->mnt_sb);

	if (ret)

		kern_unmount(mnt);

	else

		erofs_ishare_mnt = mnt;

	return ret;

}



void erofs_exit_ishare(void)