From 8c339c3535728179acc94deb5b922aebcfac9ab6 Mon Sep 17 00:00:00 2001 From: Thomas Huth Date: Thu, 3 Jun 2021 16:13:34 -0400 Subject: [PATCH 2/4] block/file-posix: Fix problem with fallocate(PUNCH_HOLE) on GPFS RH-Author: Thomas Huth Message-id: <20210603161334.607005-2-thuth@redhat.com> Patchwork-id: 101673 O-Subject: [RHEL-8.5.0 qemu-kvm PATCH 1/1] block/file-posix: Fix problem with fallocate(PUNCH_HOLE) on GPFS Bugzilla: 1944861 RH-Acked-by: Kevin Wolf RH-Acked-by: Max Reitz RH-Acked-by: Cornelia Huck RH-Acked-by: Laszlo Ersek A customer reported that running qemu-img convert -t none -O qcow2 -f qcow2 input.qcow2 output.qcow2 fails for them with the following error message when the images are stored on a GPFS file system : qemu-img: error while writing sector 0: Invalid argument After analyzing the strace output, it seems like the problem is in handle_aiocb_write_zeroes(): The call to fallocate(FALLOC_FL_PUNCH_HOLE) returns EINVAL, which can apparently happen if the file system has a different idea of the granularity of the operation. It's arguably a bug in GPFS, since the PUNCH_HOLE mode should not result in EINVAL according to the man-page of fallocate(), but the file system is out there in production and so we have to deal with it. In commit 294682cc3a ("block: workaround for unaligned byte range in fallocate()") we also already applied the a work-around for the same problem to the earlier fallocate(FALLOC_FL_ZERO_RANGE) call, so do it now similar with the PUNCH_HOLE call. But instead of silently catching and returning -ENOTSUP (which causes the caller to fall back to writing zeroes), let's rather inform the user once about the buggy file system and try the other fallback instead. Signed-off-by: Thomas Huth Message-Id: <20210527172020.847617-2-thuth@redhat.com> Signed-off-by: Kevin Wolf (cherry picked from commit 73ebf29729d1a40feaa9f8ab8951b6ee6dbfbede) Bugzilla: https://bugzilla.redhat.com/show_bug.cgi?id=1944861 Signed-off-by: Thomas Huth Signed-off-by: Danilo C. L. de Paula --- block/file-posix.c | 11 +++++++++++ 1 file changed, 11 insertions(+) diff --git a/block/file-posix.c b/block/file-posix.c index 62a463229f..371572f1b0 100644 --- a/block/file-posix.c +++ b/block/file-posix.c @@ -1587,6 +1587,17 @@ static int handle_aiocb_write_zeroes(void *opaque) return ret; } s->has_fallocate = false; + } else if (ret == -EINVAL) { + /* + * Some file systems like older versions of GPFS do not like un- + * aligned byte ranges, and return EINVAL in such a case, though + * they should not do it according to the man-page of fallocate(). + * Warn about the bad filesystem and try the final fallback instead. + */ + warn_report_once("Your file system is misbehaving: " + "fallocate(FALLOC_FL_PUNCH_HOLE) returned EINVAL. " + "Please report this bug to your file sytem " + "vendor."); } else if (ret != -ENOTSUP) { return ret; } else { -- 2.27.0