From 0a3e71ac6373184a31a5d99b6eebc1c698a6e12f Mon Sep 17 00:00:00 2001
From: Thomas Huth <thuth@redhat.com>
Date: Thu, 9 Jul 2015 10:15:50 +0200
Subject: [PATCH 2/2] qga/commands-posix: Fix bug in guest-fstrim

Message-id: <1436436950-3481-2-git-send-email-thuth@redhat.com>
Patchwork-id: 66881
O-Subject: [RHEV-7.2 qemu-guest-agent PATCH 1/1] qga/commands-posix: Fix bug in guest-fstrim
Bugzilla: 1211973
RH-Acked-by: Miroslav Rezanina <mrezanin@redhat.com>
RH-Acked-by: Laszlo Ersek <lersek@redhat.com>
RH-Acked-by: Laurent Vivier <lvivier@redhat.com>

From: Justin Ossevoort <justin@quarantainenet.nl>

The FITRIM ioctl updates the fstrim_range structure it receives. This
way the caller can determine how many bytes were trimmed. The
guest-fstrim logic reuses the same fstrim_range for each filesystem,
effectively limiting each filesystem to trim at most as much as the
previous was able to trim.

If a previous filesystem would have trimmed 0 bytes, than the next
filesystem would report an error 'Invalid argument' because a FITRIM
request with length 0 is not valid.

This change resets the fstrim_range structure for each filesystem.

Signed-off-by: Justin Ossevoort <justin@quarantainenet.nl>
Reviewed-by: Thomas Huth <thuth@redhat.com>
Signed-off-by: Michael Roth <mdroth@linux.vnet.ibm.com>
(cherry picked from commit 73a652a1b08445e8d91e50cdbb2da50e571c61b3)
Signed-off-by: Thomas Huth <thuth@redhat.com>
Signed-off-by: Miroslav Rezanina <mrezanin@redhat.com>
---
 qga/commands-posix.c | 9 ++++-----
 1 file changed, 4 insertions(+), 5 deletions(-)

diff --git a/qga/commands-posix.c b/qga/commands-posix.c
index ba8de62..4449628 100644
--- a/qga/commands-posix.c
+++ b/qga/commands-posix.c
@@ -1332,11 +1332,7 @@ void qmp_guest_fstrim(bool has_minimum, int64_t minimum, Error **errp)
     struct FsMount *mount;
     int fd;
     Error *local_err = NULL;
-    struct fstrim_range r = {
-        .start = 0,
-        .len = -1,
-        .minlen = has_minimum ? minimum : 0,
-    };
+    struct fstrim_range r;
 
     slog("guest-fstrim called");
 
@@ -1360,6 +1356,9 @@ void qmp_guest_fstrim(bool has_minimum, int64_t minimum, Error **errp)
          * error means an unexpected error, so return it in those cases.  In
          * some other cases ENOTTY will be reported (e.g. CD-ROMs).
          */
+        r.start = 0;
+        r.len = -1;
+        r.minlen = has_minimum ? minimum : 0;
         ret = ioctl(fd, FITRIM, &r);
         if (ret == -1) {
             if (errno != ENOTTY && errno != EOPNOTSUPP) {
-- 
1.8.3.1