uuid_mutex in btrfs_rm_device() is pointless- 1. btrfs_rm_device() can
only delete the device of a mounted fs 2. the btrfs_control interface
doesn't add or free_stale device if the device is mounted. 3. the
contending device operations such as add/replace.. are synchronized
using the atomic BTRFS_FS_EXCL_OP flag. 4. moreover as uuid_mutex
protects the global fs_uuid list it serializes the device delete across
fsids which is pointless.
btrfs_rm_device() is already holding the device_list_mutex when it
updates the fs_devices::dev_list, so we don't need any other locks here.
Signed-off-by: Anand Jain <anand.j...@oracle.com>
---
The changes here are on top the patch other btrfs_rm_device patches..
[PATCH 1/2] btrfs: fix parent in memory total_devices after seed delete
[PATCH 2/2] btrfs: fix missing superblock update in the device delete commit
transaction
But they are not related.
fs/btrfs/volumes.c | 18 ++++++------------
1 file changed, 6 insertions(+), 12 deletions(-)
diff --git a/fs/btrfs/volumes.c b/fs/btrfs/volumes.c
index 60a6486090d3..75638e267d8b 100644
--- a/fs/btrfs/volumes.c
+++ b/fs/btrfs/volumes.c
@@ -1953,7 +1953,7 @@ void btrfs_assign_next_active_device(struct btrfs_fs_info
*fs_info,
}
int btrfs_rm_device(struct btrfs_fs_info *fs_info, const char *device_path,
- u64 devid)
+ u64 devid)
{
struct btrfs_device *device;
struct btrfs_trans_handle *trans;
@@ -1963,8 +1963,6 @@ int btrfs_rm_device(struct btrfs_fs_info *fs_info, const
char *device_path,
u64 num_devices;
int ret = 0;
- mutex_lock(&uuid_mutex);
-
num_devices = fs_devices->num_devices;
btrfs_dev_replace_read_lock(&fs_info->dev_replace);
if (btrfs_dev_replace_is_ongoing(&fs_info->dev_replace)) {
@@ -1975,22 +1973,22 @@ int btrfs_rm_device(struct btrfs_fs_info *fs_info,
const char *device_path,
ret = btrfs_check_raid_min_devices(fs_info, num_devices - 1);
if (ret)
- goto out;
+ return ret;
ret = btrfs_find_device_by_devspec(fs_info, devid, device_path,
&device);
if (ret)
- goto out;
+ return ret;
if (test_bit(BTRFS_DEV_STATE_REPLACE_TGT, &device->dev_state)) {
ret = BTRFS_ERROR_DEV_TGT_REPLACE;
- goto out;
+ return ret;
}
if (test_bit(BTRFS_DEV_STATE_WRITEABLE, &device->dev_state) &&
fs_info->fs_devices->rw_devices == 1) {
ret = BTRFS_ERROR_DEV_ONLY_WRITABLE;
- goto out;
+ return ret;
}
if (test_bit(BTRFS_DEV_STATE_WRITEABLE, &device->dev_state)) {
@@ -2000,9 +1998,7 @@ int btrfs_rm_device(struct btrfs_fs_info *fs_info, const
char *device_path,
mutex_unlock(&fs_info->chunk_mutex);
}
- mutex_unlock(&uuid_mutex);
ret = btrfs_shrink_device(device, 0);
- mutex_lock(&uuid_mutex);
if (ret)
goto error_undo;
@@ -2092,8 +2088,6 @@ int btrfs_rm_device(struct btrfs_fs_info *fs_info, const
char *device_path,
}
ret = btrfs_commit_transaction(trans);
-out:
- mutex_unlock(&uuid_mutex);
return ret;
error_undo:
@@ -2104,7 +2098,7 @@ int btrfs_rm_device(struct btrfs_fs_info *fs_info, const
char *device_path,
device->fs_devices->rw_devices++;
mutex_unlock(&fs_info->chunk_mutex);
}
- goto out;
+ return ret;
}
void btrfs_rm_dev_replace_remove_srcdev(struct btrfs_fs_info *fs_info,
--
2.7.0
--
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