We should avoid using non multi-path (mp) path for mp disks
As of now there is no good way (like api) to check that.
A workaround way is to check if the O_EXCL open is unsuccessful.
This is safe since otherwise the BTRFS_IOC_SCAN_DEV ioctl would
fail if the disk-path can not be opened with the flag O_EXCL set.
This patch also includes some (error) print format changes related
to the btrfs dev scan..
Signed-off-by: Anand Jain <anand.jain@xxxxxxxxxx>
---
cmds-device.c | 53 +++++++++++++++++++++++++++++++++++++++--------------
utils.c | 31 ++++++++++++++++++++++++-------
2 files changed, 63 insertions(+), 21 deletions(-)
diff --git a/cmds-device.c b/cmds-device.c
index 41e79d3..b8d05fd 100644
--- a/cmds-device.c
+++ b/cmds-device.c
@@ -185,7 +185,7 @@ static const char * const cmd_scan_dev_usage[] = {
static int cmd_scan_dev(int argc, char **argv)
{
- int i, fd, e;
+ int i, fd, e, ret = 0;
int checklist = 1;
int devstart = 1;
@@ -197,6 +197,21 @@ static int cmd_scan_dev(int argc, char **argv)
devstart += 1;
}
+ fd = open("/dev/btrfs-control", O_RDWR);
+ e = errno;
+ if (fd < 0) {
+ FILE *mfd = popen("lsmod | grep btrfs", "r");
+ char buf[16];
+
+ if (fread (buf, 1, sizeof (buf), mfd) > 0)
+ fprintf(stderr, "ERROR: failed to open "\
+ "/dev/btrfs-control - %s\n", strerror(e));
+ else
+ fprintf(stderr, "ERROR: btrfs kernel module "\
+ "is not loaded\n");
+ return 10;
+ }
+
if(argc<=devstart){
int ret;
@@ -210,20 +225,30 @@ static int cmd_scan_dev(int argc, char **argv)
fprintf(stderr, "ERROR: error %d while scanning\n", ret);
return 18;
}
+ printf("done\n");
return 0;
}
- fd = open("/dev/btrfs-control", O_RDWR);
- if (fd < 0) {
- perror("failed to open /dev/btrfs-control");
- return 10;
- }
-
+ printf("Scanning for Btrfs in\n");
for( i = devstart ; i < argc ; i++ ){
+ int fdt;
struct btrfs_ioctl_vol_args args;
- int ret;
+ printf(" %s ", argv[i]);
+ fflush(stdout);
- printf("Scanning for Btrfs filesystems in '%s'\n", argv[i]);
+ /*
+ * If for a multipath (mp) disk user provides the
+ * non-mp path then open with flag O_EXCL will fail,
+ * (also ioctl opens with O_EXCL), So test it before
+ * calling ioctl.
+ */
+ fdt = open(argv[i], O_RDONLY|O_EXCL);
+ if (fdt < 0) {
+ perror("ERROR");
+ ret = -1;
+ continue;
+ }
+ close(fdt);
strncpy_null(args.name, argv[i]);
/*
@@ -235,15 +260,15 @@ static int cmd_scan_dev(int argc, char **argv)
e = errno;
if( ret < 0 ){
- close(fd);
- fprintf(stderr, "ERROR: unable to scan the device '%s' - %s\n",
- argv[i], strerror(e));
- return 11;
+ fprintf(stderr, "ERROR: unable to scan - %s\n",
+ strerror(e));
+ ret = -1;
}
+ printf("found\n");
}
close(fd);
- return 0;
+ return ret;
}
static const char * const cmd_ready_dev_usage[] = {
diff --git a/utils.c b/utils.c
index a4f7b06..3a0d444 100644
--- a/utils.c
+++ b/utils.c
@@ -1105,25 +1105,32 @@ again:
if (!S_ISBLK(st.st_mode)) {
continue;
}
- fd = open(fullpath, O_RDONLY);
+ fd = open(fullpath, O_RDONLY|O_EXCL);
if (fd < 0) {
/* ignore the following errors:
ENXIO (device don't exists)
ENOMEDIUM (No medium found ->
like a cd tray empty)
+ EBUSY (when mp disk is opened
+ using non-mp path).
*/
- if(errno != ENXIO && errno != ENOMEDIUM)
+ if(errno != ENXIO && errno != ENOMEDIUM &&
+ errno != EBUSY)
fprintf(stderr, "failed to read %s: %s\n",
fullpath, strerror(errno));
continue;
}
+ close(fd);
+
+ fd = open(fullpath, O_RDONLY);
ret = btrfs_scan_one_device(fd, fullpath, &tmp_devices,
&num_devices,
BTRFS_SUPER_INFO_OFFSET);
+ close(fd);
+
if (ret == 0 && run_ioctl > 0) {
btrfs_register_one_device(fullpath);
}
- close(fd);
}
if (!list_empty(&pending_list)) {
free(pending);
@@ -1442,19 +1449,29 @@ scan_again:
continue;
}
- fd = open(fullpath, O_RDONLY);
+ /* This will fail for the multi path devices
+ * when non multipath path is used. So we avoid
+ * sending it to the kernel which eventually will
+ * fail.
+ */
+ fd = open(fullpath, O_RDONLY|O_EXCL);
if (fd < 0) {
- fprintf(stderr, "failed to open %s: %s\n",
- fullpath, strerror(errno));
+ if (errno != EBUSY) {
+ fprintf(stderr, "failed to open %s: %s\n",
+ fullpath, strerror(errno));
+ }
continue;
}
+ close(fd);
+
+ fd = open(fullpath, O_RDONLY);
ret = btrfs_scan_one_device(fd, fullpath, &tmp_devices,
&num_devices,
BTRFS_SUPER_INFO_OFFSET);
+ close(fd);
if (ret == 0 && run_ioctl > 0) {
btrfs_register_one_device(fullpath);
}
- close(fd);
}
fclose(proc_partitions);
