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authorBoris Burkov <boris@bur.io>2020-11-18 15:06:22 -0800
committerDavid Sterba <dsterba@suse.com>2020-12-09 19:16:08 +0100
commit948462294577a3870c407c16d89bb2314f0b0cfb (patch)
tree3ef24bbc5ecac9ddc42ea657752d01c6de81947c /fs/btrfs
parent8b228324a8ce03083a034dfa784bc10696ce7489 (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')
-rw-r--r--fs/btrfs/ctree.h3
-rw-r--r--fs/btrfs/disk-io.c8
-rw-r--r--fs/btrfs/free-space-cache.c28
-rw-r--r--fs/btrfs/free-space-cache.h2
-rw-r--r--fs/btrfs/super.c10
-rw-r--r--fs/btrfs/transaction.c2
6 files changed, 50 insertions, 3 deletions
diff --git a/fs/btrfs/ctree.h b/fs/btrfs/ctree.h
index 331554fd6fd1..2744e13e8eb9 100644
--- a/fs/btrfs/ctree.h
+++ b/fs/btrfs/ctree.h
@@ -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,
};
/*
diff --git a/fs/btrfs/disk-io.c b/fs/btrfs/disk-io.c
index 77c7013f69d7..2dcc5e52140c 100644
--- a/fs/btrfs/disk-io.c
+++ b/fs/btrfs/disk-io.c
@@ -2888,6 +2888,7 @@ void btrfs_clear_oneshot_options(struct btrfs_fs_info *fs_info)
int btrfs_start_pre_rw_mount(struct btrfs_fs_info *fs_info)
{
int ret;
+ const bool cache_opt = btrfs_test_opt(fs_info, SPACE_CACHE);
bool clear_free_space_tree = false;
if (btrfs_test_opt(fs_info, CLEAR_CACHE) &&
@@ -2940,6 +2941,12 @@ int btrfs_start_pre_rw_mount(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;
@@ -3410,6 +3417,7 @@ 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:
diff --git a/fs/btrfs/free-space-cache.c b/fs/btrfs/free-space-cache.c
index fe4b2176a6e8..e71def319655 100644
--- a/fs/btrfs/free-space-cache.c
+++ b/fs/btrfs/free-space-cache.c
@@ -3763,6 +3763,34 @@ int btrfs_trim_block_group_bitmaps(struct btrfs_block_group *block_group,
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
+ * 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
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,
diff --git a/fs/btrfs/super.c b/fs/btrfs/super.c
index 93514555453b..b2252184305c 100644
--- a/fs/btrfs/super.c
+++ b/fs/btrfs/super.c
@@ -552,7 +552,6 @@ 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;
@@ -562,10 +561,9 @@ 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)) {
if (btrfs_is_zoned(info)) {
btrfs_info(info,
"zoned: clearing existing space cache");
@@ -1864,6 +1862,8 @@ 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)
{
+ const 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.
@@ -1880,6 +1880,10 @@ 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)
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;
}