[1/2] file-posix: allow -EBUSY errors during write zeros on raw block devices

Commit Message

Maxim Levitsky Nov. 11, 2020, 3:39 p.m. UTC

On Linux, fallocate(fd, FALLOC_FL_PUNCH_HOLE) when it is used on a block device,
without O_DIRECT can return -EBUSY if it races with another write to the same page.

Since this is rare and discard is not a critical operation, ignore this error

Signed-off-by: Maxim Levitsky <[e-mail]>
---
 block/file-posix.c | 1 +
 1 file changed, 1 insertion(+)

Comments

Kevin Wolf Nov. 16, 2020, 2:48 p.m. UTC | #1

Am 11.11.2020 um 16:39 hat Maxim Levitsky geschrieben:
> On Linux, fallocate(fd, FALLOC_FL_PUNCH_HOLE) when it is used on a block device,
> without O_DIRECT can return -EBUSY if it races with another write to the same page.
> 
> Since this is rare and discard is not a critical operation, ignore this error
> 
> Signed-off-by: Maxim Levitsky <[e-mail]>

I'm applying this one for 5.2, it certainly shouldn't hurt and makes
things work at least, even if possibly not in the optimal way.

Patch 2 seems to be a bit less obvious and discussion is ongoing, so
that's probably more 6.0 material.

Kevin

Maxim Levitsky Jan. 7, 2021, 12:44 p.m. UTC | #2

On Mon, 2020-11-16 at 15:48 +0100, Kevin Wolf wrote:
> Am 11.11.2020 um 16:39 hat Maxim Levitsky geschrieben:
> > On Linux, fallocate(fd, FALLOC_FL_PUNCH_HOLE) when it is used on a block device,
> > without O_DIRECT can return -EBUSY if it races with another write to the same page.
> > 
> > Since this is rare and discard is not a critical operation, ignore this error
> > 
> > Signed-off-by: Maxim Levitsky <[e-mail]>
> 
> I'm applying this one for 5.2, it certainly shouldn't hurt and makes
> things work at least, even if possibly not in the optimal way.
> 
> Patch 2 seems to be a bit less obvious and discussion is ongoing, so
> that's probably more 6.0 material.
> 
> Kevin

Any feedback on patch 2?

Best regards,
	Maxim Levitsky

Patch

diff --git a/block/file-posix.c b/block/file-posix.c
index c63926d592..d5fd1dbcd2 100644
--- a/block/file-posix.c
+++ b/block/file-posix.c
@@ -1698,6 +1698,7 @@  static int handle_aiocb_write_zeroes_unmap(void *opaque)
     switch (ret) {
     case -ENOTSUP:
     case -EINVAL:
+    case -EBUSY:
         break;
     default:
         return ret;