On Mon, Feb 26, 2024 at 04:46:28PM -0600, Bill O'Donnell wrote:
> Convert the qnx4 filesystem to use the new mount API.
>
> Tested mount, umount, and remount using a qnx4 boot image.
>
> Signed-off-by: Bill O'Donnell <bodonnel@xxxxxxxxxx>
> ---
> fs/qnx4/inode.c | 49 +++++++++++++++++++++++++++++++------------------
> 1 file changed, 31 insertions(+), 18 deletions(-)
>
> diff --git a/fs/qnx4/inode.c b/fs/qnx4/inode.c
> index 6eb9bb369b57..c36fbe45a0e9 100644
> --- a/fs/qnx4/inode.c
> +++ b/fs/qnx4/inode.c
> @@ -21,6 +21,7 @@
> #include <linux/buffer_head.h>
> #include <linux/writeback.h>
> #include <linux/statfs.h>
> +#include <linux/fs_context.h>
> #include "qnx4.h"
>
> #define QNX4_VERSION 4
> @@ -30,28 +31,33 @@ static const struct super_operations qnx4_sops;
>
> static struct inode *qnx4_alloc_inode(struct super_block *sb);
> static void qnx4_free_inode(struct inode *inode);
> -static int qnx4_remount(struct super_block *sb, int *flags, char *data);
> static int qnx4_statfs(struct dentry *, struct kstatfs *);
> +static int qnx4_get_tree(struct fs_context *fc);
>
> static const struct super_operations qnx4_sops =
> {
> .alloc_inode = qnx4_alloc_inode,
> .free_inode = qnx4_free_inode,
> .statfs = qnx4_statfs,
> - .remount_fs = qnx4_remount,
> };
>
> -static int qnx4_remount(struct super_block *sb, int *flags, char *data)
> +static int qnx4_reconfigure(struct fs_context *fc)
> {
> - struct qnx4_sb_info *qs;
> + struct super_block *sb = fc->root->d_sb;
> + struct qnx4_sb_info *qs = sb->s_fs_info;
>
> sync_filesystem(sb);
> qs = qnx4_sb(sb);
> qs->Version = QNX4_VERSION;
> - *flags |= SB_RDONLY;
> + fc->sb_flags |= SB_RDONLY;
This confused me to no end because setting SB_RDONLY here
unconditionally would be wrong if it's not requested from userspace
during a remount. Because in that case the vfs wouldn't know that an
actual read-only remount request had been made which means that we don't
take the necessary protection steps to transition from read-write to
read-only. But qnx{4,6} are read-only so this is actually correct even
though it seems pretty weird.
