diff options
Diffstat (limited to 'fs/btrfs/extent-tree.c')
| -rw-r--r-- | fs/btrfs/extent-tree.c | 53 |
1 files changed, 53 insertions, 0 deletions
diff --git a/fs/btrfs/extent-tree.c b/fs/btrfs/extent-tree.c index 09aad7b447f5..dcf89bfa990d 100644 --- a/fs/btrfs/extent-tree.c +++ b/fs/btrfs/extent-tree.c @@ -3824,6 +3824,59 @@ int btrfs_extent_readonly(struct btrfs_root *root, u64 bytenr) return readonly; } +bool btrfs_inc_nocow_writers(struct btrfs_fs_info *fs_info, u64 bytenr) +{ + struct btrfs_block_group_cache *bg; + bool ret = true; + + bg = btrfs_lookup_block_group(fs_info, bytenr); + if (!bg) + return false; + + spin_lock(&bg->lock); + if (bg->ro) + ret = false; + else + atomic_inc(&bg->nocow_writers); + spin_unlock(&bg->lock); + + /* no put on block group, done by btrfs_dec_nocow_writers */ + if (!ret) + btrfs_put_block_group(bg); + + return ret; + +} + +void btrfs_dec_nocow_writers(struct btrfs_fs_info *fs_info, u64 bytenr) +{ + struct btrfs_block_group_cache *bg; + + bg = btrfs_lookup_block_group(fs_info, bytenr); + ASSERT(bg); + if (atomic_dec_and_test(&bg->nocow_writers)) + wake_up_atomic_t(&bg->nocow_writers); + /* + * Once for our lookup and once for the lookup done by a previous call + * to btrfs_inc_nocow_writers() + */ + btrfs_put_block_group(bg); + btrfs_put_block_group(bg); +} + +static int btrfs_wait_nocow_writers_atomic_t(atomic_t *a) +{ + schedule(); + return 0; +} + +void btrfs_wait_nocow_writers(struct btrfs_block_group_cache *bg) +{ + wait_on_atomic_t(&bg->nocow_writers, + btrfs_wait_nocow_writers_atomic_t, + TASK_UNINTERRUPTIBLE); +} + static const char *alloc_name(u64 flags) { switch (flags) { |