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Blame SOURCES/kvm-block-rbd-Attempt-to-parse-legacy-filenames.patch

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From 0433f2d3bd818b83908636ae240ecbfd256e0a9c Mon Sep 17 00:00:00 2001
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From: John Snow <jsnow@redhat.com>
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Date: Wed, 10 Oct 2018 20:30:13 +0100
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Subject: [PATCH 2/4] block/rbd: Attempt to parse legacy filenames
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RH-Author: John Snow <jsnow@redhat.com>
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Message-id: <20181010203015.11719-3-jsnow@redhat.com>
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Patchwork-id: 82629
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O-Subject: [RHEL8/rhel qemu-kvm PATCH 2/4] block/rbd: Attempt to parse legacy filenames
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Bugzilla: 1635585
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RH-Acked-by: Markus Armbruster <armbru@redhat.com>
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RH-Acked-by: Stefan Hajnoczi <stefanha@redhat.com>
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RH-Acked-by: Thomas Huth <thuth@redhat.com>
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From: Jeff Cody <jcody@redhat.com>
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When we converted rbd to get rid of the older key/value-centric
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encoding format, we broke compatibility with image files with backing
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file strings encoded in the old format.
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This leaves a bit of an ugly conundrum, and a hacky solution.
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If the initial attempt to parse the "proper" options fails, it assumes
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that we may have an older key/value encoded filename.  Fall back to
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attempting to parse the filename, and extract the required options from
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it.  If that fails, pass along the original error message.
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We do not support mixed modern usage alongside legacy keyvalue pair
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usage.
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A deprecation warning has been added, although care should be taken
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when actually deprecating since the impact is not limited to
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commandline or qapi usage, but also opening existing images.
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Reviewed-by: Eric Blake <eblake@redhat.com>
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Signed-off-by: Jeff Cody <jcody@redhat.com>
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Message-id: 15b332e5432ad069441f7275a46080f465d789a0.1536704901.git.jcody@redhat.com
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Signed-off-by: Jeff Cody <jcody@redhat.com>
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(cherry picked from commit 084d1d13bdb753d558b991996e7686c077bd6d80)
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Signed-off-by: John Snow <jsnow@redhat.com>
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Signed-off-by: Danilo C. L. de Paula <ddepaula@redhat.com>
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---
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 block/rbd.c | 54 ++++++++++++++++++++++++++++++++++++++++++++++++++++--
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 1 file changed, 52 insertions(+), 2 deletions(-)
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diff --git a/block/rbd.c b/block/rbd.c
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index 1e4d339..ebe0701 100644
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--- a/block/rbd.c
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+++ b/block/rbd.c
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@@ -671,6 +671,33 @@ static int qemu_rbd_convert_options(QDict *options, BlockdevOptionsRbd **opts,
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     return 0;
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 }
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+static int qemu_rbd_attempt_legacy_options(QDict *options,
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+                                           BlockdevOptionsRbd **opts,
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+                                           char **keypairs)
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+{
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+    char *filename;
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+    int r;
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+
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+    filename = g_strdup(qdict_get_try_str(options, "filename"));
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+    if (!filename) {
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+        return -EINVAL;
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+    }
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+    qdict_del(options, "filename");
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+
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+    qemu_rbd_parse_filename(filename, options, NULL);
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+
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+    /* keypairs freed by caller */
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+    *keypairs = g_strdup(qdict_get_try_str(options, "=keyvalue-pairs"));
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+    if (*keypairs) {
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+        qdict_del(options, "=keyvalue-pairs");
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+    }
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+
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+    r = qemu_rbd_convert_options(options, opts, NULL);
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+
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+    g_free(filename);
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+    return r;
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+}
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+
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 static int qemu_rbd_open(BlockDriverState *bs, QDict *options, int flags,
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                          Error **errp)
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 {
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@@ -693,8 +720,31 @@ static int qemu_rbd_open(BlockDriverState *bs, QDict *options, int flags,
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     r = qemu_rbd_convert_options(options, &opts, &local_err);
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     if (local_err) {
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-        error_propagate(errp, local_err);
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-        goto out;
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+        /* If keypairs are present, that means some options are present in
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+         * the modern option format.  Don't attempt to parse legacy option
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+         * formats, as we won't support mixed usage. */
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+        if (keypairs) {
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+            error_propagate(errp, local_err);
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+            goto out;
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+        }
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+
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+        /* If the initial attempt to convert and process the options failed,
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+         * we may be attempting to open an image file that has the rbd options
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+         * specified in the older format consisting of all key/value pairs
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+         * encoded in the filename.  Go ahead and attempt to parse the
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+         * filename, and see if we can pull out the required options. */
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+        r = qemu_rbd_attempt_legacy_options(options, &opts, &keypairs);
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+        if (r < 0) {
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+            /* Propagate the original error, not the legacy parsing fallback
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+             * error, as the latter was just a best-effort attempt. */
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+            error_propagate(errp, local_err);
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+            goto out;
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+        }
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+        /* Take care whenever deciding to actually deprecate; once this ability
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+         * is removed, we will not be able to open any images with legacy-styled
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+         * backing image strings. */
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+        error_report("RBD options encoded in the filename as keyvalue pairs "
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+                     "is deprecated");
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     }
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     /* Remove the processed options from the QDict (the visitor processes
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-- 
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1.8.3.1
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