On 1/23/24 04:16, Kanchan Joshi wrote:
On 1/23/2024 1:39 AM, Bart Van Assche wrote:
On 1/22/24 01:31, Kanchan Joshi wrote:
On 1/19/2024 7:26 PM, Kanchan Joshi wrote:
On 1/19/2024 12:24 AM, Bart Van Assche wrote:
I think the above proposal would introduce a bug: it would break the
F_GET_RW_HINT implementation.
Right. I expected to keep the exact change in GET, too, but that will
not be free from the side-effect.
The buffered-write path (block_write_full_page) picks the hint from one
inode, and the direct-write path (__blkdev_direct_IO_simple) picks the
hint from a different inode.
So, updating both seems needed here.
I stand corrected. It's possible to do away with two updates.
The direct-io code (patch 8) should rather be changed to pick the hint
from bdev inode (and not from file inode).
With that change, this patch only need to set the hint into only one
inode (bdev one). What do you think?
I think that would break direct I/O submitted by a filesystem.
By breakage do you mean not being able to set/get the hint correctly?
I tested with XFS and Ext4 direct I/O. No breakage.
The approach that you proposed is wrong from a conceptual point of view.
Zero, one or more block devices can be associated with a filesystem. It
would be wrong to try to access all associated block devices from inside
the F_SET_RW_HINT implementation. I don't think that there is any API in
the Linux kernel for iterating over all the block devices associated with
a filesystem.
Bart.
