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Blame SOURCES/kvm-block-vhdx-update-log-guid-in-header-and-first-write.patch

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From c310637234eeafe32d0eb5626f91e12b5a2399b9 Mon Sep 17 00:00:00 2001
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From: Jeffrey Cody <jcody@redhat.com>
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Date: Wed, 20 Nov 2013 19:43:55 +0100
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Subject: [PATCH 12/25] block: vhdx - update log guid in header, and first write tracker
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RH-Author: Jeffrey Cody <jcody@redhat.com>
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Message-id: <313d521b2aab6f6657de5b4fbb9cc10e58d9d5c4.1384975172.git.jcody@redhat.com>
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Patchwork-id: 55806
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O-Subject: [RHEL7 qemu-kvm PATCH 12/26] block: vhdx - update log guid in header, and first write tracker
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Bugzilla: 879234
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RH-Acked-by: Stefan Hajnoczi <stefanha@redhat.com>
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RH-Acked-by: Paolo Bonzini <pbonzini@redhat.com>
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RH-Acked-by: Fam Zheng <famz@redhat.com>
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Allow tracking of first file write in the VHDX image, as well as
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the ability to update the GUID in the header.  This is in preparation
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for log support.
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Signed-off-by: Jeff Cody <jcody@redhat.com>
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Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
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(cherry picked from commit c3906c5e8281b37a526c706596af8575d6ac00d3)
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---
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 block/vhdx.c | 30 ++++++++++++++++++++++++------
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 block/vhdx.h |  6 ++++++
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 2 files changed, 30 insertions(+), 6 deletions(-)
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Signed-off-by: Miroslav Rezanina <mrezanin@redhat.com>
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---
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 block/vhdx.c |   30 ++++++++++++++++++++++++------
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 block/vhdx.h |    6 ++++++
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 2 files changed, 30 insertions(+), 6 deletions(-)
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diff --git a/block/vhdx.c b/block/vhdx.c
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index 2efece1..49219df 100644
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--- a/block/vhdx.c
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+++ b/block/vhdx.c
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@@ -230,7 +230,7 @@ static int vhdx_probe(const uint8_t *buf, int buf_size, const char *filename)
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  *  - non-current header is updated with largest sequence number
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  */
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 static int vhdx_update_header(BlockDriverState *bs, BDRVVHDXState *s,
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-                              bool generate_data_write_guid)
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+                              bool generate_data_write_guid, MSGUID *log_guid)
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 {
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     int ret = 0;
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     int hdr_idx = 0;
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@@ -262,6 +262,11 @@ static int vhdx_update_header(BlockDriverState *bs, BDRVVHDXState *s,
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         vhdx_guid_generate(&inactive_header->data_write_guid);
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     }
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+    /* update the log guid if present */
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+    if (log_guid) {
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+        inactive_header->log_guid = *log_guid;
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+    }
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+
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     /* the header checksum is not over just the packed size of VHDXHeader,
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      * but rather over the entire 'reserved' range for the header, which is
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      * 4KB (VHDX_HEADER_SIZE). */
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@@ -294,16 +299,16 @@ exit:
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  * The VHDX spec calls for header updates to be performed twice, so that both
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  * the current and non-current header have valid info
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  */
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-static int vhdx_update_headers(BlockDriverState *bs, BDRVVHDXState *s,
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-                               bool generate_data_write_guid)
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+int vhdx_update_headers(BlockDriverState *bs, BDRVVHDXState *s,
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+                        bool generate_data_write_guid, MSGUID *log_guid)
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 {
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     int ret;
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-    ret = vhdx_update_header(bs, s, generate_data_write_guid);
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+    ret = vhdx_update_header(bs, s, generate_data_write_guid, log_guid);
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     if (ret < 0) {
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         return ret;
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     }
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-    ret = vhdx_update_header(bs, s, generate_data_write_guid);
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+    ret = vhdx_update_header(bs, s, generate_data_write_guid, log_guid);
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     return ret;
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 }
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@@ -784,6 +789,7 @@ static int vhdx_open(BlockDriverState *bs, QDict *options, int flags,
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     s->bat = NULL;
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+    s->first_visible_write = true;
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     qemu_co_mutex_init(&s->lock);
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@@ -864,7 +870,7 @@ static int vhdx_open(BlockDriverState *bs, QDict *options, int flags,
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     }
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     if (flags & BDRV_O_RDWR) {
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-        ret = vhdx_update_headers(bs, s, false);
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+        ret = vhdx_update_headers(bs, s, false, NULL);
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         if (ret < 0) {
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             goto fail;
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         }
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@@ -1022,6 +1028,18 @@ exit:
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+/* Per the spec, on the first write of guest-visible data to the file the
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+ * data write guid must be updated in the header */
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+int vhdx_user_visible_write(BlockDriverState *bs, BDRVVHDXState *s)
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+{
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+    int ret = 0;
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+    if (s->first_visible_write) {
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+        s->first_visible_write = false;
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+        ret = vhdx_update_headers(bs, s, true, NULL);
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+    }
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+    return ret;
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+}
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+
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 static coroutine_fn int vhdx_co_writev(BlockDriverState *bs, int64_t sector_num,
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                                       int nb_sectors, QEMUIOVector *qiov)
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 {
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diff --git a/block/vhdx.h b/block/vhdx.h
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index 55975a2..81785e5 100644
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--- a/block/vhdx.h
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+++ b/block/vhdx.h
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@@ -361,6 +361,7 @@ typedef struct BDRVVHDXState {
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     VHDXBatEntry *bat;
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     uint64_t bat_offset;
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+    bool first_visible_write;
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     MSGUID session_guid;
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     VHDXLogEntries log;
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@@ -373,6 +374,9 @@ typedef struct BDRVVHDXState {
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 void vhdx_guid_generate(MSGUID *guid);
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+int vhdx_update_headers(BlockDriverState *bs, BDRVVHDXState *s, bool rw,
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+                        MSGUID *log_guid);
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+
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 uint32_t vhdx_update_checksum(uint8_t *buf, size_t size, int crc_offset);
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 uint32_t vhdx_checksum_calc(uint32_t crc, uint8_t *buf, size_t size,
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                             int crc_offset);
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@@ -402,4 +406,6 @@ void vhdx_log_data_le_export(VHDXLogDataSector *d);
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 void vhdx_log_entry_hdr_le_import(VHDXLogEntryHeader *hdr);
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 void vhdx_log_entry_hdr_le_export(VHDXLogEntryHeader *hdr);
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+int vhdx_user_visible_write(BlockDriverState *bs, BDRVVHDXState *s);
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+
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 #endif
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-- 
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1.7.1
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