diff options
| author | Nikolay Borisov <nborisov@suse.com> | 2019-03-27 14:24:11 +0200 |
|---|---|---|
| committer | David Sterba <dsterba@suse.com> | 2019-04-29 19:02:37 +0200 |
| commit | 8e75fd893b0608aa3a45f8654b71960423df5f3e (patch) | |
| tree | 1b4985f7563cc2a6a1877e03e3178d202342a7a0 | |
| parent | 4ca7365606ca08282da248fbc270abf58a515e20 (diff) | |
btrfs: Stop using call_rcu for device freeing
btrfs_device structs are freed from RCU context since device iteration
is protected by RCU. Currently this is achieved by using call_rcu since
no blocking functions are called within btrfs_free_device. Future
refactoring of pending/pinned chunks will require calling sleeping
functions.
This patch is in preparation for these changes by simply switching from
RCU callbacks to explicit calls of synchronize_rcu and calling
btrfs_free_device directly. This is functionally equivalent, making sure
that there are no readers at that time.
Signed-off-by: Nikolay Borisov <nborisov@suse.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
| -rw-r--r-- | fs/btrfs/volumes.c | 20 | ||||
| -rw-r--r-- | fs/btrfs/volumes.h | 1 |
2 files changed, 8 insertions, 13 deletions
diff --git a/fs/btrfs/volumes.c b/fs/btrfs/volumes.c index 66b8b492d6f5..2bde9e9c188e 100644 --- a/fs/btrfs/volumes.c +++ b/fs/btrfs/volumes.c @@ -1231,14 +1231,6 @@ again: mutex_unlock(&uuid_mutex); } -static void free_device_rcu(struct rcu_head *head) -{ - struct btrfs_device *device; - - device = container_of(head, struct btrfs_device, rcu); - btrfs_free_device(device); -} - static void btrfs_close_bdev(struct btrfs_device *device) { if (!device->bdev) @@ -1286,7 +1278,8 @@ static void btrfs_close_one_device(struct btrfs_device *device) list_replace_rcu(&device->dev_list, &new_device->dev_list); new_device->fs_devices = device->fs_devices; - call_rcu(&device->rcu, free_device_rcu); + synchronize_rcu(); + btrfs_free_device(device); } static int close_fs_devices(struct btrfs_fs_devices *fs_devices) @@ -2243,7 +2236,8 @@ int btrfs_rm_device(struct btrfs_fs_info *fs_info, const char *device_path, btrfs_scratch_superblocks(device->bdev, device->name->str); btrfs_close_bdev(device); - call_rcu(&device->rcu, free_device_rcu); + synchronize_rcu(); + btrfs_free_device(device); if (cur_devices->open_devices == 0) { while (fs_devices) { @@ -2311,7 +2305,8 @@ void btrfs_rm_dev_replace_free_srcdev(struct btrfs_fs_info *fs_info, } btrfs_close_bdev(srcdev); - call_rcu(&srcdev->rcu, free_device_rcu); + synchronize_rcu(); + btrfs_free_device(srcdev); /* if this is no devs we rather delete the fs_devices */ if (!fs_devices->num_devices) { @@ -2369,7 +2364,8 @@ void btrfs_destroy_dev_replace_tgtdev(struct btrfs_device *tgtdev) btrfs_scratch_superblocks(tgtdev->bdev, tgtdev->name->str); btrfs_close_bdev(tgtdev); - call_rcu(&tgtdev->rcu, free_device_rcu); + synchronize_rcu(); + btrfs_free_device(tgtdev); } static struct btrfs_device *btrfs_find_device_by_path( diff --git a/fs/btrfs/volumes.h b/fs/btrfs/volumes.h index b9912b910d6d..d3658a4e65db 100644 --- a/fs/btrfs/volumes.h +++ b/fs/btrfs/volumes.h @@ -118,7 +118,6 @@ struct btrfs_device { struct scrub_ctx *scrub_ctx; struct btrfs_work work; - struct rcu_head rcu; /* readahead state */ atomic_t reada_in_flight; |