Re: [PATCH] minix: convert minix to use the new mount api

[Eric Sandeen <sandeen@redhat.com>]

On 3/5/24 3:08 PM, Bill O'Donnell wrote:
> Convert the minix filesystem to use the new mount API.
> 
> Tested using mount and remount on minix device.
> 
> Signed-off-by: Bill O'Donnell <bodonnel@redhat.com>
> ---
>  fs/minix/inode.c | 64 ++++++++++++++++++++++++++++++++++--------------
>  1 file changed, 46 insertions(+), 18 deletions(-)
> 
> diff --git a/fs/minix/inode.c b/fs/minix/inode.c
> index 73f37f298087..248e78a118e7 100644
> --- a/fs/minix/inode.c
> +++ b/fs/minix/inode.c
> @@ -20,11 +20,11 @@
>  #include <linux/mpage.h>
>  #include <linux/vfs.h>
>  #include <linux/writeback.h>
> +#include <linux/fs_context.h>
>  
>  static int minix_write_inode(struct inode *inode,
>  		struct writeback_control *wbc);
>  static int minix_statfs(struct dentry *dentry, struct kstatfs *buf);
> -static int minix_remount (struct super_block * sb, int * flags, char * data);
>  
>  static void minix_evict_inode(struct inode *inode)
>  {
> @@ -111,19 +111,19 @@ static const struct super_operations minix_sops = {
>  	.evict_inode	= minix_evict_inode,
>  	.put_super	= minix_put_super,
>  	.statfs		= minix_statfs,
> -	.remount_fs	= minix_remount,
>  };
>  
> -static int minix_remount (struct super_block * sb, int * flags, char * data)
> +static int minix_reconfigure(struct fs_context *fc)
>  {
> -	struct minix_sb_info * sbi = minix_sb(sb);
>  	struct minix_super_block * ms;
> +	struct super_block *sb = fc->root->d_sb;
> +	struct minix_sb_info * sbi = sb->s_fs_info;
>  
>  	sync_filesystem(sb);
>  	ms = sbi->s_ms;
> -	if ((bool)(*flags & SB_RDONLY) == sb_rdonly(sb))
> +	if ((bool)(fc->sb_flags & SB_RDONLY) == sb_rdonly(sb))
>  		return 0;
> -	if (*flags & SB_RDONLY) {
> +	if (fc->sb_flags & SB_RDONLY) {
>  		if (ms->s_state & MINIX_VALID_FS ||
>  		    !(sbi->s_mount_state & MINIX_VALID_FS))
>  			return 0;
> @@ -170,7 +170,7 @@ static bool minix_check_superblock(struct super_block *sb)
>  	return true;
>  }
>  
> -static int minix_fill_super(struct super_block *s, void *data, int silent)
> +static int minix_fill_super(struct super_block *s, struct fs_context *fc)
>  {
>  	struct buffer_head *bh;
>  	struct buffer_head **map;
> @@ -180,6 +180,7 @@ static int minix_fill_super(struct super_block *s, void *data, int silent)
>  	struct inode *root_inode;
>  	struct minix_sb_info *sbi;
>  	int ret = -EINVAL;
> +	int silent = fc->sb_flags & SB_SILENT;
>  
>  	sbi = kzalloc(sizeof(struct minix_sb_info), GFP_KERNEL);
>  	if (!sbi)
> @@ -371,6 +372,39 @@ static int minix_fill_super(struct super_block *s, void *data, int silent)
>  	return ret;
>  }
>  
> +static int minix_get_tree(struct fs_context *fc)
> +{
> +	 return get_tree_bdev(fc, minix_fill_super);
> +}
> +
> +static void minix_free_fc(struct fs_context *fc)
> +{
> +	kfree(fc->fs_private);
> +}
> +
> +struct minix_context {
> +	unsigned long s_mount_opts;

This is never used. The context is typically used for storing mount
options during parsing, but minix has none, so this isn't needed.

> +};
> +
> +static const struct fs_context_operations minix_context_ops = {
> +	.get_tree	= minix_get_tree,
> +	.reconfigure	= minix_reconfigure,
> +	.free		= minix_free_fc,
> +};
> +
> +static int minix_init_fs_context(struct fs_context *fc)
> +{
> +	struct minix_context *ctx;
> +
> +	ctx = kzalloc(sizeof(struct minix_context), GFP_KERNEL);
> +	if (!ctx)
> +		return -ENOMEM;
> +	fc->ops = &minix_context_ops;
> +	fc->fs_private = ctx;

and so it doesn't need to be allocated & stored, or freed.

-Eric