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/transaction.c | |
parent | 8b228324a8ce03083a034dfa784bc10696ce7489 (diff) | |
download | linux-948462294577a3870c407c16d89bb2314f0b0cfb.tar.bz2 |
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/transaction.c')
-rw-r--r-- | fs/btrfs/transaction.c | 2 |
1 files changed, 2 insertions, 0 deletions
diff --git a/fs/btrfs/transaction.c b/fs/btrfs/transaction.c index 6b7156712486..8e0f7a1029c6 100644 --- a/fs/btrfs/transaction.c +++ b/fs/btrfs/transaction.c @@ -1796,6 +1796,8 @@ static void update_super_roots(struct btrfs_fs_info *fs_info) super->root_level = root_item->level; if (btrfs_test_opt(fs_info, SPACE_CACHE)) super->cache_generation = root_item->generation; + else if (test_bit(BTRFS_FS_CLEANUP_SPACE_CACHE_V1, &fs_info->flags)) + super->cache_generation = 0; if (test_bit(BTRFS_FS_UPDATE_UUID_TREE_GEN, &fs_info->flags)) super->uuid_tree_generation = root_item->generation; } |