Re: [PATCH -V4 2/2] ext4: Use -1 as the fake block number for delayed new buffer_head

["Aneesh Kumar K.V" <aneesh.kumar@linux.vnet.ibm.com>]

On Wed, Apr 29, 2009 at 11:35:21AM -0400, Theodore Tso wrote:
> On Wed, Apr 29, 2009 at 10:17:21AM +0530, Aneesh Kumar K.V wrote:
> > Block number '0' should not be used as the fake block number for
> > the delayed new buffer. This will result in vfs calling umap_underlying_metadata for
> > block number '0'. So  use -1 instead.
> 
> sector_t is an unsigned type, so we probably want to use ~0 instead of
> -1.  I can fix this up before we apply into the patch queue.
> 
> Are we agreed both of these should probably be pushed to Linus for
> 2.6.30?
> 

With ABAT I am seeing the below error during fsstress run.

EXT4-fs: mounted filesystem sdb1 with ordered data mode
attempt to access beyond end of device
sdb1: rw=1, want=0, limit=136713087
Buffer I/O error on device sdb1, logical block 18446744073709551615
lost page write due to I/O error on sdb1
attempt to access beyond end of device
sdb1: rw=1, want=0, limit=136713087
Buffer I/O error on device sdb1, logical block 18446744073709551615
lost page write due to I/O error on sdb1
attempt to access beyond end of device
sdb1: rw=1, want=0, limit=136713087
Buffer I/O error on device sdb1, logical block 18446744073709551615
lost page write due to I/O error on sdb1
attempt to access beyond end of device
sdb1: rw=1, want=0, limit=136713087


That is the logical block number ~0. Well that would imply we are trying
to write the buffer_head which is marked delay.


-aneesh