Merge remote-tracking branch 'remotes/kwolf-gitlab/tags/for-upstream' into staging

Block layer patches

- rbd: fix handling of holes in .bdrv_co_block_status
- Fix potential crash in bdrv_set_backing_hd()
- vhost-user-blk export: Fix shutdown with requests in flight
- FUSE export: Fix build failure on FreeBSD
- Documentation improvements

# gpg: Signature made Tue 01 Feb 2022 15:14:24 GMT
# gpg:                using RSA key DC3DEB159A9AF95D3D7456FE7F09B272C88F2FD6
# gpg:                issuer "kwolf@redhat.com"
# gpg: Good signature from "Kevin Wolf <kwolf@redhat.com>" [full]
# Primary key fingerprint: DC3D EB15 9A9A F95D 3D74  56FE 7F09 B272 C88F 2FD6

* remotes/kwolf-gitlab/tags/for-upstream:
  block/rbd: workaround for ceph issue #53784
  block/rbd: fix handling of holes in .bdrv_co_block_status
  qemu-img: Unify [-b [-F]] documentation
  qsd: Document fuse's allow-other option
  block.h: remove outdated comment
  block/export/fuse: Fix build failure on FreeBSD
  block/export/fuse: Rearrange if-else-if ladder in fuse_fallocate()
  block/export: Fix vhost-user-blk shutdown with requests in flight
  block: bdrv_set_backing_hd(): use drained section
  qemu-storage-daemon: Fix typo in vhost-user-blk help

Signed-off-by: Peter Maydell <peter.maydell@linaro.org>

3 files changed, 75 insertions, 27 deletions

diff --git a/block/export/fuse.c b/block/export/fuse.c
index 6710d8aed8..fdda8e3c81 100644
--- a/block/export/fuse.c
+++ b/block/export/fuse.c
@@ -625,11 +625,33 @@ static void fuse_fallocate(fuse_req_t req, fuse_ino_t inode, int mode,
         return;
     }
 
+#ifdef CONFIG_FALLOCATE_PUNCH_HOLE
     if (mode & FALLOC_FL_KEEP_SIZE) {
         length = MIN(length, blk_len - offset);
     }
+#endif /* CONFIG_FALLOCATE_PUNCH_HOLE */
 
-    if (mode & FALLOC_FL_PUNCH_HOLE) {
+    if (!mode) {
+        /* We can only fallocate at the EOF with a truncate */
+        if (offset < blk_len) {
+            fuse_reply_err(req, EOPNOTSUPP);
+            return;
+        }
+
+        if (offset > blk_len) {
+            /* No preallocation needed here */
+            ret = fuse_do_truncate(exp, offset, true, PREALLOC_MODE_OFF);
+            if (ret < 0) {
+                fuse_reply_err(req, -ret);
+                return;
+            }
+        }
+
+        ret = fuse_do_truncate(exp, offset + length, true,
+                               PREALLOC_MODE_FALLOC);
+    }
+#ifdef CONFIG_FALLOCATE_PUNCH_HOLE
+    else if (mode & FALLOC_FL_PUNCH_HOLE) {
         if (!(mode & FALLOC_FL_KEEP_SIZE)) {
             fuse_reply_err(req, EINVAL);
             return;
@@ -643,6 +665,7 @@ static void fuse_fallocate(fuse_req_t req, fuse_ino_t inode, int mode,
             length -= size;
         } while (ret == 0 && length > 0);
     }
+#endif /* CONFIG_FALLOCATE_PUNCH_HOLE */
 #ifdef CONFIG_FALLOCATE_ZERO_RANGE
     else if (mode & FALLOC_FL_ZERO_RANGE) {
         if (!(mode & FALLOC_FL_KEEP_SIZE) && offset + length > blk_len) {
@@ -665,25 +688,7 @@ static void fuse_fallocate(fuse_req_t req, fuse_ino_t inode, int mode,
         } while (ret == 0 && length > 0);
     }
 #endif /* CONFIG_FALLOCATE_ZERO_RANGE */
-    else if (!mode) {
-        /* We can only fallocate at the EOF with a truncate */
-        if (offset < blk_len) {
-            fuse_reply_err(req, EOPNOTSUPP);
-            return;
-        }
-
-        if (offset > blk_len) {
-            /* No preallocation needed here */
-            ret = fuse_do_truncate(exp, offset, true, PREALLOC_MODE_OFF);
-            if (ret < 0) {
-                fuse_reply_err(req, -ret);
-                return;
-            }
-        }
-
-        ret = fuse_do_truncate(exp, offset + length, true,
-                               PREALLOC_MODE_FALLOC);
-    } else {
+    else {
         ret = -EOPNOTSUPP;
     }
 
diff --git a/block/export/vhost-user-blk-server.c b/block/export/vhost-user-blk-server.c
index 1862563336..a129204c44 100644
--- a/block/export/vhost-user-blk-server.c
+++ b/block/export/vhost-user-blk-server.c
@@ -172,6 +172,7 @@ vu_blk_discard_write_zeroes(VuBlkExport *vexp, struct iovec *iov,
     return VIRTIO_BLK_S_IOERR;
 }
 
+/* Called with server refcount increased, must decrease before returning */
 static void coroutine_fn vu_blk_virtio_process_req(void *opaque)
 {
     VuBlkReq *req = opaque;
@@ -286,10 +287,12 @@ static void coroutine_fn vu_blk_virtio_process_req(void *opaque)
     }
 
     vu_blk_req_complete(req);
+    vhost_user_server_unref(server);
     return;
 
 err:
     free(req);
+    vhost_user_server_unref(server);
 }
 
 static void vu_blk_process_vq(VuDev *vu_dev, int idx)
@@ -310,6 +313,8 @@ static void vu_blk_process_vq(VuDev *vu_dev, int idx)
 
         Coroutine *co =
             qemu_coroutine_create(vu_blk_virtio_process_req, req);
+
+        vhost_user_server_ref(server);
         qemu_coroutine_enter(co);
     }
 }
diff --git a/block/rbd.c b/block/rbd.c
index def96292e0..8f183eba2a 100644
--- a/block/rbd.c
+++ b/block/rbd.c
@@ -1279,11 +1279,11 @@ static int qemu_rbd_diff_iterate_cb(uint64_t offs, size_t len,
     RBDDiffIterateReq *req = opaque;
 
     assert(req->offs + req->bytes <= offs);
-    /*
-     * we do not diff against a snapshot so we should never receive a callback
-     * for a hole.
-     */
-    assert(exists);
+
+    /* treat a hole like an unallocated area and bail out */
+    if (!exists) {
+        return 0;
+    }
 
     if (!req->exists && offs > req->offs) {
         /*
@@ -1320,6 +1320,7 @@ static int coroutine_fn qemu_rbd_co_block_status(BlockDriverState *bs,
     int status, r;
     RBDDiffIterateReq req = { .offs = offset };
     uint64_t features, flags;
+    uint64_t head = 0;
 
     assert(offset + bytes <= s->image_size);
 
@@ -1347,7 +1348,43 @@ static int coroutine_fn qemu_rbd_co_block_status(BlockDriverState *bs,
         return status;
     }
 
-    r = rbd_diff_iterate2(s->image, NULL, offset, bytes, true, true,
+#if LIBRBD_VERSION_CODE < LIBRBD_VERSION(1, 17, 0)
+    /*
+     * librbd had a bug until early 2022 that affected all versions of ceph that
+     * supported fast-diff. This bug results in reporting of incorrect offsets
+     * if the offset parameter to rbd_diff_iterate2 is not object aligned.
+     * Work around this bug by rounding down the offset to object boundaries.
+     * This is OK because we call rbd_diff_iterate2 with whole_object = true.
+     * However, this workaround only works for non cloned images with default
+     * striping.
+     *
+     * See: https://tracker.ceph.com/issues/53784
+     */
+
+    /* check if RBD image has non-default striping enabled */
+    if (features & RBD_FEATURE_STRIPINGV2) {
+        return status;
+    }
+
+#pragma GCC diagnostic push
+#pragma GCC diagnostic ignored "-Wdeprecated-declarations"
+    /*
+     * check if RBD image is a clone (= has a parent).
+     *
+     * rbd_get_parent_info is deprecated from Nautilus onwards, but the
+     * replacement rbd_get_parent is not present in Luminous and Mimic.
+     */
+    if (rbd_get_parent_info(s->image, NULL, 0, NULL, 0, NULL, 0) != -ENOENT) {
+        return status;
+    }
+#pragma GCC diagnostic pop
+
+    head = req.offs & (s->object_size - 1);
+    req.offs -= head;
+    bytes += head;
+#endif
+
+    r = rbd_diff_iterate2(s->image, NULL, req.offs, bytes, true, true,
                           qemu_rbd_diff_iterate_cb, &req);
     if (r < 0 && r != QEMU_RBD_EXIT_DIFF_ITERATE2) {
         return status;
@@ -1366,7 +1403,8 @@ static int coroutine_fn qemu_rbd_co_block_status(BlockDriverState *bs,
         status = BDRV_BLOCK_ZERO | BDRV_BLOCK_OFFSET_VALID;
     }
 
-    *pnum = req.bytes;
+    assert(req.bytes > head);
+    *pnum = req.bytes - head;
     return status;
 }