[Xen-changelog] [xen-unstable] blktap: Handle qcow backing files correctly.

[Xen patchbot-unstable <patchbot-unstable@xxxxxxxxxxxxxxxxxxx>]

# HG changeset patch
# User Keir Fraser <keir.fraser@xxxxxxxxxx>
# Date 1224511704 -3600
# Node ID 0a09de68c54153243d9293c82cbb6ddca4e4a76d
# Parent  cbc254c59dd06f1f4197461bc51ca8dbcdf5b3af
blktap: Handle qcow backing files correctly.

Signed-off-by: Stefano Stabellini <stefano.stabellini@xxxxxxxxxxxxx>
---
 tools/blktap/drivers/block-qcow.c  |   18 ++++------
 tools/blktap/drivers/block-qcow2.c |   62 +++++++++++++++++++++++++++++++------
 2 files changed, 61 insertions(+), 19 deletions(-)

diff -r cbc254c59dd0 -r 0a09de68c541 tools/blktap/drivers/block-qcow.c
--- a/tools/blktap/drivers/block-qcow.c Mon Oct 20 15:05:48 2008 +0100
+++ b/tools/blktap/drivers/block-qcow.c Mon Oct 20 15:08:24 2008 +0100
@@ -734,8 +734,8 @@ static int tdqcow_open (struct disk_driv
 
        DPRINTF("QCOW: Opening %s\n",name);
 
-       o_flags = O_DIRECT | O_LARGEFILE | 
-               ((flags == TD_RDONLY) ? O_RDONLY : O_RDWR);
+       /* Since we don't handle O_DIRECT correctly, don't use it */
+       o_flags = O_LARGEFILE | ((flags == TD_RDONLY) ? O_RDONLY : O_RDWR);
        fd = open(name, o_flags);
        if (fd < 0) {
                DPRINTF("Unable to open %s (%d)\n",name,0 - errno);
@@ -1385,7 +1385,7 @@ static int tdqcow_get_parent_id(struct d
        filename[len]  = '\0';
 
        id->name       = strdup(filename);
-       id->drivertype = DISK_TYPE_QCOW;
+       id->drivertype = DISK_TYPE_AIO;
        err            = 0;
  out:
        free(buf);
@@ -1397,17 +1397,15 @@ static int tdqcow_validate_parent(struct
 {
        struct stat stats;
        uint64_t psize, csize;
-       struct tdqcow_state *c = (struct tdqcow_state *)child->private;
-       struct tdqcow_state *p = (struct tdqcow_state *)parent->private;
-       
-       if (stat(p->name, &stats))
+       
+       if (stat(parent->name, &stats))
                return -EINVAL;
-       if (get_filesize(p->name, &psize, &stats))
+       if (get_filesize(parent->name, &psize, &stats))
                return -EINVAL;
 
-       if (stat(c->name, &stats))
+       if (stat(child->name, &stats))
                return -EINVAL;
-       if (get_filesize(c->name, &csize, &stats))
+       if (get_filesize(child->name, &csize, &stats))
                return -EINVAL;
 
        if (csize != psize)
diff -r cbc254c59dd0 -r 0a09de68c541 tools/blktap/drivers/block-qcow2.c
--- a/tools/blktap/drivers/block-qcow2.c        Mon Oct 20 15:05:48 2008 +0100
+++ b/tools/blktap/drivers/block-qcow2.c        Mon Oct 20 15:08:24 2008 +0100
@@ -34,6 +34,7 @@
 #include "tapdisk.h"
 #include "tapaio.h"
 #include "bswap.h"
+#include "blk.h"
 
 #define USE_AIO
 
@@ -1902,6 +1903,42 @@ repeat:
 
 #endif 
 
+static int get_filesize(char *filename, uint64_t *size, struct stat *st)
+{
+       int fd;
+       QCowHeader header;
+
+       /*Set to the backing file size*/
+       fd = open(filename, O_RDONLY);
+       if (fd < 0)
+               return -1;
+       if (read(fd, &header, sizeof(header)) < sizeof(header)) {
+               close(fd);
+               return -1;
+       }
+       close(fd);
+       
+       be32_to_cpus(&header.magic);
+       be32_to_cpus(&header.version);
+       be64_to_cpus(&header.size);
+       if (header.magic == QCOW_MAGIC && header.version == QCOW_VERSION) {
+               *size = header.size >> SECTOR_SHIFT;
+               return 0;
+       }
+
+       if(S_ISBLK(st->st_mode)) {
+               fd = open(filename, O_RDONLY);
+               if (fd < 0)
+                       return -1;
+               if (blk_getimagesize(fd, size) != 0) {
+                       close(fd);
+                       return -1;
+               }
+               close(fd);
+       } else *size = (st->st_size >> SECTOR_SHIFT);   
+       return 0;
+}
+
 /**
  * @return 
  *        0 if parent id successfully retrieved;
@@ -1916,7 +1953,7 @@ static int qcow_get_parent_id(struct dis
                return TD_NO_PARENT;
 
        id->name = strdup(s->backing_file);
-       id->drivertype = DISK_TYPE_QCOW2;
+       id->drivertype = DISK_TYPE_AIO;
 
        return 0;
 }
@@ -1924,15 +1961,22 @@ static int qcow_validate_parent(struct d
 static int qcow_validate_parent(struct disk_driver *child, 
                struct disk_driver *parent, td_flag_t flags)
 {
-       struct BDRVQcowState *cs = (struct BDRVQcowState*) child->private;
-       struct BDRVQcowState *ps = (struct BDRVQcowState*) parent->private;
-
-       if (ps->total_sectors != cs->total_sectors) {
-               DPRINTF("qcow_validate_parent(): %#"PRIx64" != %#"PRIx64"\n",
-                       ps->total_sectors, cs->total_sectors);
+       struct stat stats;
+       uint64_t psize, csize;
+       
+       if (stat(parent->name, &stats))
                return -EINVAL;
-       }
-       
+       if (get_filesize(parent->name, &psize, &stats))
+               return -EINVAL;
+
+       if (stat(child->name, &stats))
+               return -EINVAL;
+       if (get_filesize(child->name, &csize, &stats))
+               return -EINVAL;
+
+       if (csize != psize)
+               return -EINVAL;
+
        return 0;
 }
 

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