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From: Christoph Hellwig <hch@lst.de>
To: "Daniel P. Berrange" <berrange@redhat.com>
Cc: Christoph Hellwig <hch@lst.de>, qemu-devel@nongnu.org
Subject: Re: [Qemu-devel] QEMU online guest disk resize wrt host block devices
Date: Thu, 1 Sep 2011 17:55:43 +0200	[thread overview]
Message-ID: <20110901155543.GA11219@lst.de> (raw)
In-Reply-To: <20110901143034.GJ14462@redhat.com>

Please try the attached (untested) patch:


Index: qemu/block/raw-posix.c
===================================================================
--- qemu.orig/block/raw-posix.c	2011-09-01 17:37:42.579651525 +0200
+++ qemu/block/raw-posix.c	2011-09-01 17:43:28.882967337 +0200
@@ -645,10 +645,23 @@ static void raw_close(BlockDriverState *
 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;
+       }
+       return 0;
+
+    } else {
+        return -ENOTSUP;
+    }
     return 0;
 }
 
@@ -1167,6 +1180,7 @@ 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,
@@ -1288,6 +1302,7 @@ 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,
@@ -1389,6 +1404,7 @@ 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,
@@ -1510,6 +1526,7 @@ 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,

  reply	other threads:[~2011-09-01 15:55 UTC|newest]

Thread overview: 10+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2011-09-01 13:27 [Qemu-devel] QEMU online guest disk resize wrt host block devices Daniel P. Berrange
2011-09-01 14:05 ` Christoph Hellwig
2011-09-01 14:30   ` Daniel P. Berrange
2011-09-01 15:55     ` Christoph Hellwig [this message]
2011-09-02 15:00       ` Daniel P. Berrange
2011-09-07 11:02       ` [Qemu-devel] [PATCH] block: allow resizing of images residing on host devices Christoph Hellwig
2011-09-09  9:37         ` Kevin Wolf
2011-09-01 14:27 ` [Qemu-devel] QEMU online guest disk resize wrt host block devices Daniel P. Berrange
2011-09-01 15:56   ` Christoph Hellwig
2011-09-05 13:03     ` Kevin Wolf

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