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.j...@oracle.com> Signed-off-by: Qu Wenruo <quwen...@cn.fujitsu.com> --- 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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