| Message ID | 1405648543-8966-1-git-send-email-quwenruo@cn.fujitsu.com (mailing list archive) |
|---|---|
| State | Superseded |
| Headers | show |
On Fri, Jul 18, 2014 at 09:55:43AM +0800, Qu Wenruo wrote: > When page aligned start and len passed to extent_fiemap(), the result is > good, but when start and len is not aligned, e.g. start = 1 and len = > 4095 is passed to extent_fiemap(), it returns no extent. > > The problem is that start and len is all rounded down which causes the > problem. ALIGN rounds up, not down. So the wrong rounding will use incorrect start (4096) and finds no extents if there's eg. only one [0,4095]. > This patch will round down start and round up (start + len) to > return right extent. > > Reported-by: Chandan Rajendra <chandan@linux.vnet.ibm.com> > Signed-off-by: Qu Wenruo <quwenruo@cn.fujitsu.com> Reviewed-by: David Sterba <dsterba@suse.cz> -- To unsubscribe from this list: send the line "unsubscribe linux-btrfs" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
-------- Original Message -------- Subject: Re: [PATCH] btrfs: Return right extent when fiemap gives unaligned offset and len. From: David Sterba <dsterba@suse.cz> To: Qu Wenruo <quwenruo@cn.fujitsu.com> Date: 2014?07?24? 20:17 > On Fri, Jul 18, 2014 at 09:55:43AM +0800, Qu Wenruo wrote: >> When page aligned start and len passed to extent_fiemap(), the result is >> good, but when start and len is not aligned, e.g. start = 1 and len = >> 4095 is passed to extent_fiemap(), it returns no extent. >> >> The problem is that start and len is all rounded down which causes the >> problem. > ALIGN rounds up, not down. So the wrong rounding will use incorrect start > (4096) and finds no extents if there's eg. only one [0,4095]. Sorry for the wrong description in patch. Should I reword the patch and send a v2 patch? Thanks, Qu > >> This patch will round down start and round up (start + len) to >> return right extent. >> >> Reported-by: Chandan Rajendra <chandan@linux.vnet.ibm.com> >> Signed-off-by: Qu Wenruo <quwenruo@cn.fujitsu.com> > Reviewed-by: David Sterba <dsterba@suse.cz> -- To unsubscribe from this list: send the line "unsubscribe linux-btrfs" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
On Fri, Jul 25, 2014 at 09:29:05AM +0800, Qu Wenruo wrote: > > -------- Original Message -------- > Subject: Re: [PATCH] btrfs: Return right extent when fiemap gives unaligned > offset and len. > From: David Sterba <dsterba@suse.cz> > To: Qu Wenruo <quwenruo@cn.fujitsu.com> > Date: 2014?07?24? 20:17 > >On Fri, Jul 18, 2014 at 09:55:43AM +0800, Qu Wenruo wrote: > >>When page aligned start and len passed to extent_fiemap(), the result is > >>good, but when start and len is not aligned, e.g. start = 1 and len = > >>4095 is passed to extent_fiemap(), it returns no extent. > >> > >>The problem is that start and len is all rounded down which causes the > >>problem. > >ALIGN rounds up, not down. So the wrong rounding will use incorrect start > >(4096) and finds no extents if there's eg. only one [0,4095]. > Sorry for the wrong description in patch. > Should I reword the patch and send a v2 patch? You already did, but yes please. -- To unsubscribe from this list: send the line "unsubscribe linux-btrfs" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
diff --git a/fs/btrfs/extent_io.c b/fs/btrfs/extent_io.c index a389820..1c70cff 100644 --- a/fs/btrfs/extent_io.c +++ b/fs/btrfs/extent_io.c @@ -4213,8 +4213,8 @@ int extent_fiemap(struct inode *inode, struct fiemap_extent_info *fieinfo, return -ENOMEM; path->leave_spinning = 1; - start = ALIGN(start, BTRFS_I(inode)->root->sectorsize); - len = ALIGN(len, BTRFS_I(inode)->root->sectorsize); + start = round_down(start, BTRFS_I(inode)->root->sectorsize); + len = round_up(max, BTRFS_I(inode)->root->sectorsize) - start; /* * lookup the last file extent. We're not using i_size here
When page aligned start and len passed to extent_fiemap(), the result is good, but when start and len is not aligned, e.g. start = 1 and len = 4095 is passed to extent_fiemap(), it returns no extent. The problem is that start and len is all rounded down which causes the problem. This patch will round down start and round up (start + len) to return right extent. Reported-by: Chandan Rajendra <chandan@linux.vnet.ibm.com> Signed-off-by: Qu Wenruo <quwenruo@cn.fujitsu.com> --- fs/btrfs/extent_io.c | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-)