On 8/20/11 9:29 PM, Allison Henderson wrote: > This bug was reported by Lukas Czerner while working on a > new patch to add discard support for loop devices using > punch hole. > > The bug is happens because the data type for logical blocks is s/is // > not large enough to calculate the block offset for holes that are Should that be "the _byte_ offset for holes ...?" > very large. This bug is resolved by casting the ext4_lblk_t > to an loff_t before calculating the byte offset of the block. > > Reviewed-and-Tested-by: Lukas Czerner <lczerner@xxxxxxxxxx> > > Signed-off-by: Allison Henderson <achender@xxxxxxxxxxxxxxxxxx> I wonder if it'd be more straightforward to just use a mask to compute these rather than the right shift / left shift, but no big deal I guess esp. since we need the intermediate value anyway? Aside from the question about the commit message, Reviewed-by: Eric Sandeen <sandeen@xxxxxxxxxx> > --- > :100644 100644 0d7617d... b417e47... M fs/ext4/extents.c > fs/ext4/extents.c | 4 ++-- > 1 files changed, 2 insertions(+), 2 deletions(-) > > diff --git a/fs/ext4/extents.c b/fs/ext4/extents.c > index 0d7617d..b417e47 100644 > --- a/fs/ext4/extents.c > +++ b/fs/ext4/extents.c > @@ -4179,8 +4179,8 @@ int ext4_ext_punch_hole(struct file *file, loff_t offset, loff_t length) > EXT4_BLOCK_SIZE_BITS(sb); > last_block = (offset + length) >> EXT4_BLOCK_SIZE_BITS(sb); > > - first_block_offset = first_block << EXT4_BLOCK_SIZE_BITS(sb); > - last_block_offset = last_block << EXT4_BLOCK_SIZE_BITS(sb); > + first_block_offset = ((loff_t)first_block) << EXT4_BLOCK_SIZE_BITS(sb); > + last_block_offset = ((loff_t)last_block) << EXT4_BLOCK_SIZE_BITS(sb); > > first_page = (offset + PAGE_CACHE_SIZE - 1) >> PAGE_CACHE_SHIFT; > last_page = (offset + length) >> PAGE_CACHE_SHIFT; -- To unsubscribe from this list: send the line "unsubscribe linux-ext4" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
