Re: [PATCH] Fix journal detection on HFS+.

[Andrew Morton <akpm@linux-foundation.org>]

On Tue, 11 Nov 2008 12:56:47 -0800
Warren Turkal <wt@penguintechs.org> wrote:

> The code was unconditionally assumming that the volume had a jounal if the
> jounal attribute was set in the volume header. However, the volume also has to
> have a non-zero journal info block to actually have a journal.

OK, but so what?

Presumably there is some situation in which this is causing you a
problem, but what is that situation, and what was the kernel's
behaviour in that situation?

> Signed-off-by: Warren Turkal <wt@penguintechs.org>
> ---
>  fs/hfsplus/super.c |   11 +++++++++--
>  1 files changed, 9 insertions(+), 2 deletions(-)
> 
> diff --git a/fs/hfsplus/super.c b/fs/hfsplus/super.c
> index eb74531..128101b 100644
> --- a/fs/hfsplus/super.c
> +++ b/fs/hfsplus/super.c
> @@ -17,9 +17,16 @@
>  
>  static struct inode *hfsplus_alloc_inode(struct super_block *sb);
>  static void hfsplus_destroy_inode(struct inode *inode);
> +static bool hfsplus_vol_has_journal(struct hfsplus_vh *vhdr);
>  
>  #include "hfsplus_fs.h"
>  
> +static bool hfsplus_vol_has_journal(struct hfsplus_vh *vhdr)
> +{
> +	return (vhdr->attributes & cpu_to_be32(HFSPLUS_VOL_JOURNALED) &&
> +				vhdr->journal_info_block);
> +}
> +
>  struct inode *hfsplus_iget(struct super_block *sb, unsigned long ino)
>  {
>  	struct hfs_find_data fd;
> @@ -260,7 +267,7 @@ static int hfsplus_remount(struct super_block *sb, int *flags, char *data)
>  			printk(KERN_WARNING "hfs: filesystem is marked locked, leaving read-only.\n");
>  			sb->s_flags |= MS_RDONLY;
>  			*flags |= MS_RDONLY;
> -		} else if (vhdr->attributes & cpu_to_be32(HFSPLUS_VOL_JOURNALED)) {
> +		} else if (hfsplus_vol_has_journal(vhdr)) {
>  			printk(KERN_WARNING "hfs: filesystem is marked journaled, leaving read-only.\n");
>  			sb->s_flags |= MS_RDONLY;
>  			*flags |= MS_RDONLY;
> @@ -356,7 +363,7 @@ static int hfsplus_fill_super(struct super_block *sb, void *data, int silent)
>  	} else if (vhdr->attributes & cpu_to_be32(HFSPLUS_VOL_SOFTLOCK)) {
>  		printk(KERN_WARNING "hfs: Filesystem is marked locked, mounting read-only.\n");
>  		sb->s_flags |= MS_RDONLY;
> -	} else if ((vhdr->attributes & cpu_to_be32(HFSPLUS_VOL_JOURNALED)) && !(sb->s_flags & MS_RDONLY)) {
> +	} else if (hfsplus_vol_has_journal(vhdr) && !(sb->s_flags & MS_RDONLY)) {
>  		printk(KERN_WARNING "hfs: write access to a journaled filesystem is not supported, "
>  		       "use the force option at your own risk, mounting read-only.\n");
>  		sb->s_flags |= MS_RDONLY;

The patch itself looks OK to me.