5b15e2ecaf
Notable changes:
* The only big change is the switch to using a custom QIOChannel for
savevm-async, because the previously used QEMUFileOps was dropped.
Changes to the current implementation:
* Switch to vector based methods as required for an IO channel. For
short reads the passed-in IO vector is stuffed with zeroes at the
end, just to be sure.
* For reading: The documentation in include/io/channel.h states that
at least one byte should be read, so also error out when whe are
at the very end instead of returning 0.
* For reading: Fix off-by-one error when request goes beyond end.
The wrong code piece was:
if ((pos + size) > maxlen) {
size = maxlen - pos - 1;
}
Previously, the last byte would not be read. It's actually
possible to get a snapshot .raw file that has content all the way
up the final 512 byte (= BDRV_SECTOR_SIZE) boundary without any
trailing zero bytes (I wrote a script to do it).
Luckily, it didn't cause a real issue, because qemu_loadvm_state()
is not interested in the final (i.e. QEMU_VM_VMDESCRIPTION)
section. The buffer for reading it is simply freed up afterwards
and the function will assume that it read the whole section, even
if that's not the case.
* For writing: Make use of the generated blk_pwritev() wrapper
instead of manually wrapping the coroutine to simplify and save a
few lines.
* Adapt to changed interfaces for blk_{pread,pwrite}:
* a9262f551e ("block: Change blk_{pread,pwrite}() param order")
* 3b35d4542c ("block: Add a 'flags' param to blk_pread()")
* bf5b16fa40 ("block: Make blk_{pread,pwrite}() return 0 on success")
Those changes especially affected the qemu-img dd patches, because
the context also changed, but also some of our block drivers used
the functions.
* Drop qemu-common.h include: it got renamed after essentially
everything was moved to other headers. The only remaining user I
could find for things dropped from the header between 7.0 and 7.1
was qemu_get_vm_name() in the iscsi-initiatorname patch, but it
already includes the header to which the function was moved.
Signed-off-by: Fiona Ebner <f.ebner@proxmox.com>
78 lines
2.9 KiB
Diff
78 lines
2.9 KiB
Diff
From 0000000000000000000000000000000000000000 Mon Sep 17 00:00:00 2001
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From: Wolfgang Bumiller <w.bumiller@proxmox.com>
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Date: Mon, 6 Apr 2020 12:16:38 +0200
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Subject: [PATCH] PVE: [Up] glusterfs: allow partial reads
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This should deal with qemu bug #1644754 until upstream
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decides which way to go. The general direction seems to be
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away from sector based block APIs and with that in mind, and
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when comparing to other network block backends (eg. nfs)
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treating partial reads as errors doesn't seem to make much
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sense.
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Signed-off-by: Thomas Lamprecht <t.lamprecht@proxmox.com>
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---
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block/gluster.c | 10 +++++++++-
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1 file changed, 9 insertions(+), 1 deletion(-)
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diff --git a/block/gluster.c b/block/gluster.c
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index 93da76bc31..1079b6186b 100644
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--- a/block/gluster.c
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+++ b/block/gluster.c
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@@ -57,6 +57,7 @@ typedef struct GlusterAIOCB {
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int ret;
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Coroutine *coroutine;
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AioContext *aio_context;
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+ bool is_write;
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} GlusterAIOCB;
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typedef struct BDRVGlusterState {
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@@ -752,8 +753,10 @@ static void gluster_finish_aiocb(struct glfs_fd *fd, ssize_t ret,
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acb->ret = 0; /* Success */
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} else if (ret < 0) {
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acb->ret = -errno; /* Read/Write failed */
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+ } else if (acb->is_write) {
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+ acb->ret = -EIO; /* Partial write - fail it */
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} else {
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- acb->ret = -EIO; /* Partial read/write - fail it */
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+ acb->ret = 0; /* Success */
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}
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aio_co_schedule(acb->aio_context, acb->coroutine);
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@@ -1022,6 +1025,7 @@ static coroutine_fn int qemu_gluster_co_pwrite_zeroes(BlockDriverState *bs,
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acb.ret = 0;
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acb.coroutine = qemu_coroutine_self();
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acb.aio_context = bdrv_get_aio_context(bs);
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+ acb.is_write = true;
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ret = glfs_zerofill_async(s->fd, offset, bytes, gluster_finish_aiocb, &acb);
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if (ret < 0) {
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@@ -1203,9 +1207,11 @@ static coroutine_fn int qemu_gluster_co_rw(BlockDriverState *bs,
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acb.aio_context = bdrv_get_aio_context(bs);
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if (write) {
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+ acb.is_write = true;
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ret = glfs_pwritev_async(s->fd, qiov->iov, qiov->niov, offset, 0,
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gluster_finish_aiocb, &acb);
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} else {
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+ acb.is_write = false;
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ret = glfs_preadv_async(s->fd, qiov->iov, qiov->niov, offset, 0,
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gluster_finish_aiocb, &acb);
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}
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@@ -1269,6 +1275,7 @@ static coroutine_fn int qemu_gluster_co_flush_to_disk(BlockDriverState *bs)
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acb.ret = 0;
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acb.coroutine = qemu_coroutine_self();
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acb.aio_context = bdrv_get_aio_context(bs);
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+ acb.is_write = true;
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ret = glfs_fsync_async(s->fd, gluster_finish_aiocb, &acb);
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if (ret < 0) {
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@@ -1317,6 +1324,7 @@ static coroutine_fn int qemu_gluster_co_pdiscard(BlockDriverState *bs,
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acb.ret = 0;
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acb.coroutine = qemu_coroutine_self();
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acb.aio_context = bdrv_get_aio_context(bs);
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+ acb.is_write = true;
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ret = glfs_discard_async(s->fd, offset, bytes, gluster_finish_aiocb, &acb);
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if (ret < 0) {
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