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| author |   Nikolay Borisov <nborisov@suse.com> | 2019-05-09 18:11:11 +0300 |
|---|---|---|
| committer |   David Sterba <dsterba@suse.com> | 2019-07-01 13:34:59 +0200 |
| commit | 0b6f5d408bb5df3101eb1944b1f301dea50c7e7e (patch) | |
| tree | 1e4cc071f098729f54b015990f77704290a58531 | |
| parent | btrfs: Always use a cached extent_state in btrfs_lock_and_flush_ordered_range (diff) | |
| download | linux-dev-0b6f5d408bb5df3101eb1944b1f301dea50c7e7e.tar.xz linux-dev-0b6f5d408bb5df3101eb1944b1f301dea50c7e7e.zip | |
btrfs: Add comments on locking of several device-related fields
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 | 4 | ||||
| -rw-r--r-- | fs/btrfs/volumes.h | 11 |
2 files changed, 11 insertions, 4 deletions
diff --git a/fs/btrfs/volumes.c b/fs/btrfs/volumes.c index 5514ae801f4c..776f5c7ca7c5 100644 --- a/fs/btrfs/volumes.c +++ b/fs/btrfs/volumes.c @@ -239,7 +239,9 @@ static int __btrfs_map_block(struct btrfs_fs_info *fs_info, * chunk_mutex * ----------- * protects chunks, adding or removing during allocation, trim or when a new - * device is added/removed + * device is added/removed. Additionally it also protects post_commit_list of + * individual devices, since they can be added to the transaction's + * post_commit_list only with chunk_mutex held. * * cleaner_mutex * ------------- diff --git a/fs/btrfs/volumes.h b/fs/btrfs/volumes.h index 4a7a4d90ded8..fea7b65a712e 100644 --- a/fs/btrfs/volumes.h +++ b/fs/btrfs/volumes.h @@ -43,8 +43,8 @@ struct btrfs_pending_bios { #define BTRFS_DEV_STATE_FLUSH_SENT (4) struct btrfs_device { - struct list_head dev_list; - struct list_head dev_alloc_list; + struct list_head dev_list; /* device_list_mutex */ + struct list_head dev_alloc_list; /* chunk mutex */ struct list_head post_commit_list; /* chunk mutex */ struct btrfs_fs_devices *fs_devices; struct btrfs_fs_info *fs_info; @@ -229,9 +229,14 @@ struct btrfs_fs_devices { * this mutex lock. */ struct mutex device_list_mutex; + + /* List of all devices, protected by device_list_mutex */ struct list_head devices; - /* devices not currently being allocated */ + /* + * Devices which can satisfy space allocation. Protected by + * chunk_mutex + */ struct list_head alloc_list; struct btrfs_fs_devices *seed; |