Qu Wenruo
2014-Jun-10 08:53 UTC
[PATCH] btrfs: When devices with same dev uuid occurs, only add the one with largest generation.
Since btrfs currently use dulicated dev uuid when doing device replace,
the following problem will happen:
1) mount with device A missing using degraded mode.
2) replace device A with device B.
3) device A reappears.
4) umount btrfs fs.
5) mount btrfs fs.
After step 5), btrfs will still use device A even device B has a larger
generation.
The patch will judge generation when difference device with same dev
uuid.
And the patch should be applied after Anand's patch:
https://patchwork.kernel.org/patch/4309651/
Cc: Anand Jain <Anand.Jain@oracle.com>
Signed-off-by: Qu Wenruo <quwenruo@cn.fujitsu.com>
---
fs/btrfs/volumes.c | 3 ++-
1 file changed, 2 insertions(+), 1 deletion(-)
diff --git a/fs/btrfs/volumes.c b/fs/btrfs/volumes.c
index 0a5017a..07f0cf7 100644
--- a/fs/btrfs/volumes.c
+++ b/fs/btrfs/volumes.c
@@ -508,7 +508,8 @@ static noinline int device_list_add(const char *path,
ret = 1;
device->fs_devices = fs_devices;
- } else if (!device->name || strcmp(device->name->str, path)) {
+ } else if (!device->name || (strcmp(device->name->str, path)
&&
+ found_transid > device->generation)) {
/*
* When FS is already mounted.
* 1. If you are here and if the device->name is NULL that means
--
2.0.0
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