Messages in this thread | | | Date | Wed, 28 Oct 2009 23:00:22 -0700 | From | Andrew Morton <> | Subject | Re: [PATCH] Fix generic_block_fiemap for files bigger than 4GB |
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On Mon, 26 Oct 2009 18:24:28 +0100 Mike Hommey <mh@glandium.org> wrote:
> Because of an integer overflow on start_blk, various kind of wrong results > would be returned by the generic_block_fiemap handler, such as no extents > when there is a 4GB+ hole at the beginning of the file, or wrong fe_logical > when an extent starts after the first 4GB. > > Signed-off-by: Mike Hommey <mh@glandium.org> > --- > fs/ioctl.c | 2 +- > 1 files changed, 1 insertions(+), 1 deletions(-) > > diff --git a/fs/ioctl.c b/fs/ioctl.c > index 7b17a14..6c75110 100644 > --- a/fs/ioctl.c > +++ b/fs/ioctl.c > @@ -254,7 +254,7 @@ int __generic_block_fiemap(struct inode *inode, > u64 len, get_block_t *get_block) > { > struct buffer_head tmp; > - unsigned int start_blk; > + unsigned long long start_blk; > long long length = 0, map_len = 0; > u64 logical = 0, phys = 0, size = 0; > u32 flags = FIEMAP_EXTENT_MERGED;
Well. Should it be unsigned long long, or u64 or sector_t? Or even loff_t.
The code's a bit confused about types in there. And it's made much more confusing by the moronic and wholly unnecessary use of macros for blk_to_logical() and logical_to_blk().
It's also unhelpful that the `u64 start' argument forgot to get itself documented in the kerneldoc comment. Sigh.
Ah, generic_block_fiemap() has it:
* @start: The initial block to map
I guess u64 was logical there as it comes in from userspace. But at some boundary we should start talking kernel types so I suspect the correct thing to do here is to use sector_t?
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