@@ -559,6 +559,9 @@ enum {
/* Indicate that the discard workqueue can service discards. */
BTRFS_FS_DISCARD_RUNNING,
+
+ /* Indicate that we need to cleanup space cache v1 */
+ BTRFS_FS_CLEANUP_SPACE_CACHE_V1,
};
/*
@@ -2885,6 +2885,12 @@ int btrfs_mount_rw(struct btrfs_fs_info *fs_info)
}
}
+ if (cache_opt != btrfs_free_space_cache_v1_active(fs_info)) {
+ ret = btrfs_set_free_space_cache_v1_active(fs_info, cache_opt);
+ if (ret)
+ goto out;
+ }
+
ret = btrfs_resume_balance_async(fs_info);
if (ret)
goto out;
@@ -3346,6 +3352,7 @@ int __cold open_ctree(struct super_block *sb, struct btrfs_fs_devices *fs_device
return ret;
}
}
+
set_bit(BTRFS_FS_OPEN, &fs_info->flags);
clear_oneshot:
@@ -3992,6 +3992,34 @@ int btrfs_write_out_ino_cache(struct btrfs_root *root,
return ret;
}
+bool btrfs_free_space_cache_v1_active(struct btrfs_fs_info *fs_info)
+{
+ return btrfs_super_cache_generation(fs_info->super_copy);
+}
+
+int btrfs_set_free_space_cache_v1_active(struct btrfs_fs_info *fs_info,
+ bool active)
+{
+ struct btrfs_trans_handle *trans;
+ int ret;
+
+ /*
+ * update_super_roots will appropriately set
+ * fs_info->super_copy->cache_generation based on the SPACE_CACHE
+ * option, so all we have to do is trigger a transaction commit.
+ */
+ trans = btrfs_start_transaction(fs_info->tree_root, 0);
+ if (IS_ERR(trans))
+ return PTR_ERR(trans);
+
+ if (!active)
+ set_bit(BTRFS_FS_CLEANUP_SPACE_CACHE_V1, &fs_info->flags);
+
+ ret = btrfs_commit_transaction(trans);
+ clear_bit(BTRFS_FS_CLEANUP_SPACE_CACHE_V1, &fs_info->flags);
+ return ret;
+}
+
#ifdef CONFIG_BTRFS_FS_RUN_SANITY_TESTS
/*
* Use this if you need to make a bitmap or extent entry specifically, it
@@ -148,6 +148,9 @@ 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,
@@ -511,7 +511,6 @@ int btrfs_parse_options(struct btrfs_fs_info *info, char *options,
{
substring_t args[MAX_OPT_ARGS];
char *p, *num;
- u64 cache_gen;
int intarg;
int ret = 0;
char *compress_type;
@@ -521,10 +520,9 @@ int btrfs_parse_options(struct btrfs_fs_info *info, char *options,
bool saved_compress_force;
int no_compress = 0;
- cache_gen = btrfs_super_cache_generation(info->super_copy);
if (btrfs_fs_compat_ro(info, FREE_SPACE_TREE))
btrfs_set_opt(info->mount_opt, FREE_SPACE_TREE);
- else if (cache_gen)
+ else if (btrfs_free_space_cache_v1_active(info))
btrfs_set_opt(info->mount_opt, SPACE_CACHE);
/*
@@ -1810,6 +1808,8 @@ static inline void btrfs_remount_begin(struct btrfs_fs_info *fs_info,
static inline void btrfs_remount_cleanup(struct btrfs_fs_info *fs_info,
unsigned long old_opts)
{
+ bool cache_opt = btrfs_test_opt(fs_info, SPACE_CACHE);
+
/*
* We need to cleanup all defragable inodes if the autodefragment is
* close or the filesystem is read only.
@@ -1826,6 +1826,10 @@ static inline void btrfs_remount_cleanup(struct btrfs_fs_info *fs_info,
else if (btrfs_raw_test_opt(old_opts, DISCARD_ASYNC) &&
!btrfs_test_opt(fs_info, DISCARD_ASYNC))
btrfs_discard_cleanup(fs_info);
+
+ /* If we toggled space cache */
+ if (cache_opt != btrfs_free_space_cache_v1_active(fs_info))
+ btrfs_set_free_space_cache_v1_active(fs_info, cache_opt);
}
static int btrfs_remount(struct super_block *sb, int *flags, char *data)
@@ -1761,6 +1761,8 @@ 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;
}
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. Signed-off-by: Boris Burkov <boris@bur.io> --- fs/btrfs/ctree.h | 3 +++ fs/btrfs/disk-io.c | 7 +++++++ fs/btrfs/free-space-cache.c | 28 ++++++++++++++++++++++++++++ fs/btrfs/free-space-cache.h | 3 +++ fs/btrfs/super.c | 10 +++++++--- fs/btrfs/transaction.c | 2 ++ 6 files changed, 50 insertions(+), 3 deletions(-)