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authorBoris Burkov <boris@bur.io>2020-11-19 02:06:22 +0300
committerDavid Sterba <dsterba@suse.com>2020-12-09 21:16:08 +0300
commit948462294577a3870c407c16d89bb2314f0b0cfb (patch)
tree3ef24bbc5ecac9ddc42ea657752d01c6de81947c /fs/btrfs/super.c
parent8b228324a8ce03083a034dfa784bc10696ce7489 (diff)
downloadlinux-948462294577a3870c407c16d89bb2314f0b0cfb.tar.xz
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/super.c')
-rw-r--r--fs/btrfs/super.c10
1 files changed, 7 insertions, 3 deletions
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)