[Qemu-devel] [PATCH 01/24] block: allow resizing of images residing on host devices

[Kevin Wolf <kwolf@redhat.com>]

From: Christoph Hellwig <hch@lst.de>

Allow to resize images that reside on host devices up to the available
space.  This allows to grow images after resizing the device manually or
vice versa.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Kevin Wolf <kwolf@redhat.com>
---
 block/raw-posix.c |   24 +++++++++++++++++++++---
 1 files changed, 21 insertions(+), 3 deletions(-)

diff --git a/block/raw-posix.c b/block/raw-posix.c
index 305998d..0b5e225 100644
--- a/block/raw-posix.c
+++ b/block/raw-posix.c
@@ -649,10 +649,24 @@ static void raw_close(BlockDriverState *bs)
 static int raw_truncate(BlockDriverState *bs, int64_t offset)
 {
     BDRVRawState *s = bs->opaque;
-    if (s->type != FTYPE_FILE)
-        return -ENOTSUP;
-    if (ftruncate(s->fd, offset) < 0)
+    struct stat st;
+
+    if (fstat(s->fd, &st)) {
         return -errno;
+    }
+
+    if (S_ISREG(st.st_mode)) {
+        if (ftruncate(s->fd, offset) < 0) {
+            return -errno;
+        }
+    } else if (S_ISCHR(st.st_mode) || S_ISBLK(st.st_mode)) {
+       if (offset > raw_getlength(bs)) {
+           return -EINVAL;
+       }
+    } else {
+        return -ENOTSUP;
+    }
+
     return 0;
 }
 
@@ -1178,6 +1192,7 @@ static BlockDriver bdrv_host_device = {
 
     .bdrv_read          = raw_read,
     .bdrv_write         = raw_write,
+    .bdrv_truncate      = raw_truncate,
     .bdrv_getlength	= raw_getlength,
     .bdrv_get_allocated_file_size
                         = raw_get_allocated_file_size,
@@ -1299,6 +1314,7 @@ static BlockDriver bdrv_host_floppy = {
 
     .bdrv_read          = raw_read,
     .bdrv_write         = raw_write,
+    .bdrv_truncate      = raw_truncate,
     .bdrv_getlength	= raw_getlength,
     .bdrv_get_allocated_file_size
                         = raw_get_allocated_file_size,
@@ -1400,6 +1416,7 @@ static BlockDriver bdrv_host_cdrom = {
 
     .bdrv_read          = raw_read,
     .bdrv_write         = raw_write,
+    .bdrv_truncate      = raw_truncate,
     .bdrv_getlength     = raw_getlength,
     .bdrv_get_allocated_file_size
                         = raw_get_allocated_file_size,
@@ -1521,6 +1538,7 @@ static BlockDriver bdrv_host_cdrom = {
 
     .bdrv_read          = raw_read,
     .bdrv_write         = raw_write,
+    .bdrv_truncate      = raw_truncate,
     .bdrv_getlength     = raw_getlength,
     .bdrv_get_allocated_file_size
                         = raw_get_allocated_file_size,
-- 
1.7.6.4