Hi David, Thanks for your reply :)
On 2018/7/30 17:47, David Howells wrote: > Gao Xiang <gaoxian...@huawei.com> wrote: > >>> sb->s_flags |= MS_RDONLY | MS_NOATIME; > > This should be using SB_* rather than MS_* for interaction with sb->s_flags. Yes, I saw the related discussion and your submission in the linux-fsdevel mailing list last year. :D The code of erofs once had to support from 3.13 ~ the current kernel, therefore I didn't turn MS_RDONLY into SB_RDONLY. But it seems that "vfs: Suppress MS_* flag defs within the kernel unless explicitly enabled" tends to remove them all. I have submitted a patch to linux-erofs mailing list for preview. https://lists.ozlabs.org/pipermail/linux-erofs/2018-July/000282.html > >>> drivers/staging/erofs/super.c: In function 'erofs_mount': >>> drivers/staging/erofs/super.c:501:10: warning: passing argument 5 of >>> 'mount_bdev' makes integer from pointer without a cast [-Wint-conversion] >>> &priv, erofs_fill_super); >>> ^~~~~~~~~~~~~~~~ >>> In file included from include/linux/buffer_head.h:12:0, >>> from drivers/staging/erofs/super.c:14: >>> include/linux/fs.h:2151:23: note: expected 'size_t {aka long unsigned int}' >>> but argument is of type 'int (*)(struct super_block *, void *, int)' >>> extern struct dentry *mount_bdev(struct file_system_type *fs_type, >>> ^~~~~~~~~~ >>> drivers/staging/erofs/super.c:500:9: error: too few arguments to function >>> 'mount_bdev' >>> return mount_bdev(fs_type, flags, dev_name, >>> ^~~~~~~~~~ > > There's a patch in Al Viro's tree that passes a size_t argument indicating the > size of the mount data from mount down into the filesystem and into the > helpers as the data may be on a kernel stack or in kernel .rodata rather than > in a full page of its own. > > https://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs.git > > Currently this is commit 0a191e4505a4f255e6513b49426213da69bf0e80 > > vfs: Require specification of size of mount data for internal mounts I just fixed according to the latest linux-next tree (the same patchset, also for preview) https://lists.ozlabs.org/pipermail/linux-erofs/2018-July/000284.html Once I tend to use void *data to pass more mount arguments on stack, eg. struct erofs_mount_private { const char *dev_name; char *options; }; ... struct erofs_mount_private priv = { .dev_name = dev_name, .options = data }; return mount_bdev(fs_type, flags, dev_name, &priv, erofs_fill_super); However, I have no idea if it is safe to do so in the future, so I also change it into a more stardard way. BTW, It seems that Greg's staging tree doesn't have Al Viro's submission... And I have little experience to handle that, so I just ask Chao for help... Thanks for your kindly reminder :) Thanks, Gao Xiang > > David >
