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authorPaolo Bonzini <pbonzini@redhat.com>2012-06-13 07:41:28 +0200
committerMichael Roth <mdroth@linux.vnet.ibm.com>2012-06-21 17:59:27 -0500
commiteab5fd5989a1ac48d123ccaec7346ce325b9ee77 (patch)
tree2552c109491a2b1070b306bd6dcead17622de0dc /qga/commands-posix.c
parentaf02203fbe03f0634fea26a6e30febdeed14ede9 (diff)
qemu-ga: add guest-fstrim command
FITRIM is a mounted filesystem feature to discard (or "trim") blocks which are not in use by the filesystem. This is useful for solid-state drives (SSDs) and thinly-provisioned storage. Provide access to the feature from the host so that filesystems can be trimmed periodically or before migration. Here is an example using scsi_debug: # modprobe scsi_debug lbpu=1 lbpws=1 # sg_vpd -p0xb2 /dev/sdb Logical block provisioning VPD page (SBC): Unmap command supported (LBPU): 1 Write same (16) with unmap bit supported (LBWS): 1 Write same (10) with unmap bit supported (LBWS10): 0 # mke2fs /dev/sdb # cat /sys/bus/pseudo/drivers/scsi_debug/map 1-616,16257-16383 # mount /dev/sdb /run/media/pbonzini/test # dd if=/dev/zero of=/run/media/pbonzini/test/file # cat map 1-616,645-1588,1599-4026,4029-16383 # rm /run/media/pbonzini/test/file # ./qemu-ga /dev/fd/0 {"execute":"guest-fstrim"} {"return": {}} # cat map 1-612 Signed-off-by: Paolo Bonzini <pbonzini@redhat.com> Reviewed-by: Luiz Capitulino <lcapitulino@redhat.com> Reviewed-by: Michal Privoznik <mprivozn@redhat.com> Signed-off-by: Michael Roth <mdroth@linux.vnet.ibm.com>
Diffstat (limited to 'qga/commands-posix.c')
-rw-r--r--qga/commands-posix.c78
1 files changed, 75 insertions, 3 deletions
diff --git a/qga/commands-posix.c b/qga/commands-posix.c
index b1a7ce627c..ce9042123c 100644
--- a/qga/commands-posix.c
+++ b/qga/commands-posix.c
@@ -38,9 +38,12 @@ extern char **environ;
#include <sys/socket.h>
#include <net/if.h>
-#if defined(__linux__) && defined(FIFREEZE)
+#ifdef FIFREEZE
#define CONFIG_FSFREEZE
#endif
+#ifdef FITRIM
+#define CONFIG_FSTRIM
+#endif
#endif
void qmp_guest_shutdown(bool has_mode, const char *mode, Error **err)
@@ -312,8 +315,7 @@ static void guest_file_init(void)
/* linux-specific implementations. avoid this if at all possible. */
#if defined(__linux__)
-#if defined(CONFIG_FSFREEZE)
-
+#if defined(CONFIG_FSFREEZE) || defined(CONFIG_FSTRIM)
typedef struct FsMount {
char *dirname;
char *devtype;
@@ -378,6 +380,9 @@ static int build_fs_mount_list(FsMountList *mounts)
return 0;
}
+#endif
+
+#if defined(CONFIG_FSFREEZE)
/*
* Return status of freeze/thaw
@@ -525,6 +530,65 @@ static void guest_fsfreeze_cleanup(void)
}
#endif /* CONFIG_FSFREEZE */
+#if defined(CONFIG_FSTRIM)
+/*
+ * Walk list of mounted file systems in the guest, and trim them.
+ */
+void qmp_guest_fstrim(bool has_minimum, int64_t minimum, Error **err)
+{
+ int ret = 0;
+ FsMountList mounts;
+ struct FsMount *mount;
+ int fd;
+ char err_msg[512];
+ struct fstrim_range r = {
+ .start = 0,
+ .len = -1,
+ .minlen = has_minimum ? minimum : 0,
+ };
+
+ slog("guest-fstrim called");
+
+ QTAILQ_INIT(&mounts);
+ ret = build_fs_mount_list(&mounts);
+ if (ret < 0) {
+ return;
+ }
+
+ QTAILQ_FOREACH(mount, &mounts, next) {
+ fd = qemu_open(mount->dirname, O_RDONLY);
+ if (fd == -1) {
+ sprintf(err_msg, "failed to open %s, %s", mount->dirname,
+ strerror(errno));
+ error_set(err, QERR_QGA_COMMAND_FAILED, err_msg);
+ goto error;
+ }
+
+ /* We try to cull filesytems we know won't work in advance, but other
+ * filesytems may not implement fstrim for less obvious reasons. These
+ * will report EOPNOTSUPP; we simply ignore these errors. Any other
+ * error means an unexpected error, so return it in those cases. In
+ * some other cases ENOTTY will be reported (e.g. CD-ROMs).
+ */
+ ret = ioctl(fd, FITRIM, &r);
+ if (ret == -1) {
+ if (errno != ENOTTY && errno != EOPNOTSUPP) {
+ sprintf(err_msg, "failed to trim %s, %s",
+ mount->dirname, strerror(errno));
+ error_set(err, QERR_QGA_COMMAND_FAILED, err_msg);
+ close(fd);
+ goto error;
+ }
+ }
+ close(fd);
+ }
+
+error:
+ free_fs_mount_list(&mounts);
+}
+#endif /* CONFIG_FSTRIM */
+
+
#define LINUX_SYS_STATE_FILE "/sys/power/state"
#define SUSPEND_SUPPORTED 0
#define SUSPEND_NOT_SUPPORTED 1
@@ -918,7 +982,15 @@ int64_t qmp_guest_fsfreeze_thaw(Error **err)
return 0;
}
+#endif /* CONFIG_FSFREEZE */
+
+#if !defined(CONFIG_FSTRIM)
+void qmp_guest_fstrim(bool has_minimum, int64_t minimum, Error **err)
+{
+ error_set(err, QERR_UNSUPPORTED);
+ return;
+}
#endif
/* register init/cleanup routines for stateful command groups */