diff options
author | Boris Burkov <boris@bur.io> | 2020-11-18 15:06:22 -0800 |
---|---|---|
committer | David Sterba <dsterba@suse.com> | 2020-12-09 19:16:08 +0100 |
commit | 948462294577a3870c407c16d89bb2314f0b0cfb (patch) | |
tree | 3ef24bbc5ecac9ddc42ea657752d01c6de81947c /fs/btrfs/free-space-cache.h | |
parent | 8b228324a8ce03083a034dfa784bc10696ce7489 (diff) |
btrfs: keep sb cache_generation consistent with space_cache
When mounting, btrfs uses the cache_generation in the super block to
determine if space cache v1 is in use. However, by mounting with
nospace_cache or space_cache=v2, it is possible to disable space cache
v1, which does not result in un-setting cache_generation back to 0.
In order to base some logic, like mount option printing in /proc/mounts,
on the current state of the space cache rather than just the values of
the mount option, keep the value of cache_generation consistent with the
status of space cache v1.
We ensure that cache_generation > 0 iff the file system is using
space_cache v1. This requires committing a transaction on any mount
which changes whether we are using v1. (v1->nospace_cache, v1->v2,
nospace_cache->v1, v2->v1).
Since the mechanism for writing out the cache generation is transaction
commit, but we want some finer grained control over when we un-set it,
we can't just rely on the SPACE_CACHE mount option, and introduce an
fs_info flag that mount can use when it wants to unset the generation.
Reviewed-by: Josef Bacik <josef@toxicpanda.com>
Signed-off-by: Boris Burkov <boris@bur.io>
Signed-off-by: David Sterba <dsterba@suse.com>
Diffstat (limited to 'fs/btrfs/free-space-cache.h')
-rw-r--r-- | fs/btrfs/free-space-cache.h | 2 |
1 files changed, 2 insertions, 0 deletions
diff --git a/fs/btrfs/free-space-cache.h b/fs/btrfs/free-space-cache.h index 91d495e31a08..3eff615c30b8 100644 --- a/fs/btrfs/free-space-cache.h +++ b/fs/btrfs/free-space-cache.h @@ -135,6 +135,8 @@ int btrfs_trim_block_group_bitmaps(struct btrfs_block_group *block_group, u64 *trimmed, u64 start, u64 end, u64 minlen, u64 maxlen, bool async); +bool btrfs_free_space_cache_v1_active(struct btrfs_fs_info *fs_info); +int btrfs_set_free_space_cache_v1_active(struct btrfs_fs_info *fs_info, bool active); /* Support functions for running our sanity tests */ #ifdef CONFIG_BTRFS_FS_RUN_SANITY_TESTS int test_add_free_space_entry(struct btrfs_block_group *cache, |