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.
Signed-off-by: Anand Jain <anand.jain@xxxxxxxxxx>
---
utils.c | 30 +++++++++++++++++++++++++++++-
1 file changed, 29 insertions(+), 1 deletion(-)
diff --git a/utils.c b/utils.c
index 3308668..0231677 100644
--- a/utils.c
+++ b/utils.c
@@ -1105,6 +1105,13 @@ again:
if (!S_ISBLK(st.st_mode)) {
continue;
}
+
+ /* Do not test for O_EXCL here since btrfs when
+ * mounted will open with O_EXCL, and if we don't
+ * allow btrfs_scan_one_device pass thru
+ * btrfs fi show will not show the btrfs fs which
+ * are mounted
+ */
fd = open(fullpath, O_RDONLY);
if (fd < 0) {
/* ignore the following errors:
@@ -1122,10 +1129,18 @@ again:
&num_devices,
BTRFS_SUPER_INFO_OFFSET,
0ull);
+ close(fd);
+
if (ret == 0 && flags & BTRFS_SCAN_REGISTER) {
+ /* Test if the dev is already opened with O_EXCL flag
+ * if yes then no need to call ioctl since the
+ * ioctl will anyway fail.
+ */
+ fd = open(fullpath, O_RDONLY|O_EXCL);
+ if (fd < 0) continue;
+ close(fd);
btrfs_register_one_device(fullpath);
}
- close(fd);
}
if (!list_empty(&pending_list)) {
free(pending);
@@ -1444,6 +1459,12 @@ scan_again:
continue;
}
+ /* Do not test for O_EXCL here since btrfs when
+ * mounted will open with O_EXCL, and if we don't
+ * allow btrfs_scan_one_device pass thru
+ * btrfs fi show will not show the btrfs fs which
+ * are mounted
+ */
fd = open(fullpath, O_RDONLY);
if (fd < 0) {
fprintf(stderr, "failed to open %s: %s\n",
@@ -1455,6 +1476,13 @@ scan_again:
BTRFS_SUPER_INFO_OFFSET,
0ull);
if (ret == 0 && flags & BTRFS_SCAN_REGISTER) {
+ /* Test if the dev is already opened with O_EXCL flag
+ * if yes then no need to call ioctl since the
+ * ioctl will anyway fail.
+ */
+ fd = open(fullpath, O_RDONLY|O_EXCL);
+ if (fd < 0) continue;
+ close(fd);
btrfs_register_one_device(fullpath);
}
close(fd);
--
1.8.1.227.g44fe835
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