Hi Qu,
Either we need to determine missing disk when disk disappear
or when we hit by -ENODEV during IO.
Discovering the same at the time when "user" run
'btrfs fi show' or 'btrfs dev del', is just "not correct".
You might use interface as proposed here.
[PATCH RFC] btrfs: revamp /sys/fs/btrfs/<fsid>/devices
further to this I will be sending another patch which will
call the above sysfs interlace when we get the kobject
notification when disk disappear.
On 05/06/2014 02:33 PM, Qu Wenruo wrote:
Old btrfs can't find a missing btrfs device since there is no
mechanism for block layer to inform fs layer.
But we can use a workaround that only check status(by using
request_queue->queue_flags) of every device in a btrfs
filesystem when calling dev_info/rm_dev ioctl, since other ioctls
do not really cares about missing device.
Cc: Anand Jain <Anand.Jain@xxxxxxxxxx>
Signed-off-by: Qu Wenruo <quwenruo@xxxxxxxxxxxxxx>
---
fs/btrfs/ioctl.c | 1 +
fs/btrfs/volumes.c | 25 ++++++++++++++++++++++++-
fs/btrfs/volumes.h | 2 ++
3 files changed, 27 insertions(+), 1 deletion(-)
diff --git a/fs/btrfs/ioctl.c b/fs/btrfs/ioctl.c
index 0401397..7680a40 100644
--- a/fs/btrfs/ioctl.c
+++ b/fs/btrfs/ioctl.c
@@ -2606,6 +2606,7 @@ static long btrfs_ioctl_dev_info(struct btrfs_root *root, void __user *arg)
goto out;
}
+ btrfs_check_dev_missing(root, dev, 1);
di_args->devid = dev->devid;
di_args->bytes_used = dev->bytes_used;
di_args->total_bytes = dev->total_bytes;
diff --git a/fs/btrfs/volumes.c b/fs/btrfs/volumes.c
index d241130a..c7d7908 100644
--- a/fs/btrfs/volumes.c
+++ b/fs/btrfs/volumes.c
@@ -1548,9 +1548,10 @@ int btrfs_rm_device(struct btrfs_root *root, char *device_path)
* is held.
*/
list_for_each_entry(tmp, devices, dev_list) {
+ btrfs_check_dev_missing(root, tmp, 0);
if (tmp->in_fs_metadata &&
!tmp->is_tgtdev_for_dev_replace &&
- !tmp->bdev) {
+ (!tmp->bdev || tmp->missing)) {
device = tmp;
break;
}
@@ -6300,3 +6301,25 @@ int btrfs_scratch_superblock(struct btrfs_device *device)
return 0;
}
+
+/* If need_lock is set, uuid_mutex will be used */
+int btrfs_check_dev_missing(struct btrfs_root *root, struct btrfs_device *dev,
+ int need_lock)
+{
+ struct request_queue *q;
+
+ if (unlikely(!dev || !dev->bdev || !dev->bdev->bd_queue))
+ return -ENOENT;
+ q = dev->bdev->bd_queue;
+
+ if (need_lock)
+ mutex_lock(&uuid_mutex);
+ if (test_bit(QUEUE_FLAG_DEAD, &q->queue_flags) ||
+ test_bit(QUEUE_FLAG_DYING, &q->queue_flags)) {
+ dev->missing = 1;
+ root->fs_info->fs_devices->missing_devices++;
+ }
+ if (need_lock)
+ mutex_unlock(&uuid_mutex);
+ return 0;
+}
diff --git a/fs/btrfs/volumes.h b/fs/btrfs/volumes.h
index 80754f9..47a44af 100644
--- a/fs/btrfs/volumes.h
+++ b/fs/btrfs/volumes.h
@@ -356,6 +356,8 @@ unsigned long btrfs_full_stripe_len(struct btrfs_root *root,
int btrfs_finish_chunk_alloc(struct btrfs_trans_handle *trans,
struct btrfs_root *extent_root,
u64 chunk_offset, u64 chunk_size);
+int btrfs_check_dev_missing(struct btrfs_root *root, struct btrfs_device *dev,
+ int need_lock);
static inline void btrfs_dev_stat_inc(struct btrfs_device *dev,
int index)
{
--
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