From: Boris Burkov <boris@bur.io>
Date: Wed, 18 Nov 2020 15:06:16 -0800
Git-commit: 44c0ca211a4da92513fffc545b5374b45b0c4fc5
Patch-mainline: v5.11-rc1
References: bsc#1182626
Subject: [PATCH] btrfs: lift read-write mount setup from mount and remount
Mounting rw and remounting from ro to rw naturally share invariants and
functionality which result in a correctly setup rw filesystem. Luckily,
there is even a strong unity in the code which implements them. In
mount's open_ctree, these operations mostly happen after an early return
for ro file systems, and in remount, they happen in a section devoted to
remounting ro->rw, after some remount specific validation passes.
However, there are unfortunately a few differences. There are small
deviations in the order of some of the operations, remount does not
start orphan cleanup in root_tree or fs_tree, remount does not create
the free space tree, and remount does not handle "one-shot" mount
options like clear_cache and uuid tree rescan.
Since we want to add building the free space tree to remount, and also
to start the same orphan cleanup process on a filesystem mounted as ro
then remounted rw, we would benefit from unifying the logic between the
two code paths.
This patch only lifts the existing common functionality, and leaves a
natural path for fixing the discrepancies.
Reviewed-by: Josef Bacik <josef@toxicpanda.com>
Signed-off-by: Boris Burkov <boris@bur.io>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
Signed-off-by: Filipe Manana <fdmanana@suse.com>
---
fs/btrfs/disk-io.c | 89 ++++++++++++++++++++++++++--------------------
fs/btrfs/disk-io.h | 1 +
fs/btrfs/super.c | 37 ++++---------------
3 files changed, 57 insertions(+), 70 deletions(-)
diff --git a/fs/btrfs/disk-io.c b/fs/btrfs/disk-io.c
index e4ad583e7..34b27c5af 100644
--- a/fs/btrfs/disk-io.c
+++ b/fs/btrfs/disk-io.c
@@ -2878,6 +2878,52 @@ static int init_mount_fs_info(struct btrfs_fs_info *fs_info, struct super_block
return btrfs_alloc_stripe_hash_table(fs_info);
}
+/*
+ * Mounting logic specific to read-write file systems. Shared by open_ctree
+ * and btrfs_remount when remounting from read-only to read-write.
+ */
+int btrfs_start_pre_rw_mount(struct btrfs_fs_info *fs_info)
+{
+ int ret;
+
+ ret = btrfs_cleanup_fs_roots(fs_info);
+ if (ret)
+ goto out;
+
+ mutex_lock(&fs_info->cleaner_mutex);
+ ret = btrfs_recover_relocation(fs_info->tree_root);
+ mutex_unlock(&fs_info->cleaner_mutex);
+ if (ret < 0) {
+ btrfs_warn(fs_info, "failed to recover relocation: %d", ret);
+ goto out;
+ }
+
+ ret = btrfs_resume_balance_async(fs_info);
+ if (ret)
+ goto out;
+
+ ret = btrfs_resume_dev_replace_async(fs_info);
+ if (ret) {
+ btrfs_warn(fs_info, "failed to resume dev_replace");
+ goto out;
+ }
+
+ btrfs_qgroup_rescan_resume(fs_info);
+
+ if (!fs_info->uuid_root) {
+ btrfs_info(fs_info, "creating UUID tree");
+ ret = btrfs_create_uuid_tree(fs_info);
+ if (ret) {
+ btrfs_warn(fs_info,
+ "failed to create the UUID tree %d", ret);
+ goto out;
+ }
+ }
+
+out:
+ return ret;
+}
+
int __cold open_ctree(struct super_block *sb, struct btrfs_fs_devices *fs_devices,
char *options)
{
@@ -3278,22 +3324,6 @@ int __cold open_ctree(struct super_block *sb, struct btrfs_fs_devices *fs_device
if (ret)
goto fail_qgroup;
- if (!sb_rdonly(sb)) {
- ret = btrfs_cleanup_fs_roots(fs_info);
- if (ret)
- goto fail_qgroup;
-
- mutex_lock(&fs_info->cleaner_mutex);
- ret = btrfs_recover_relocation(tree_root);
- mutex_unlock(&fs_info->cleaner_mutex);
- if (ret < 0) {
- btrfs_warn(fs_info, "failed to recover relocation: %d",
- ret);
- err = -EINVAL;
- goto fail_qgroup;
- }
- }
-
location.objectid = BTRFS_FS_TREE_OBJECTID;
location.type = BTRFS_ROOT_ITEM_KEY;
location.offset = 0;
@@ -3349,34 +3379,15 @@ int __cold open_ctree(struct super_block *sb, struct btrfs_fs_devices *fs_device
}
up_read(&fs_info->cleanup_work_sem);
- ret = btrfs_resume_balance_async(fs_info);
- if (ret) {
- btrfs_warn(fs_info, "failed to resume balance: %d", ret);
- close_ctree(fs_info);
- return ret;
- }
-
- ret = btrfs_resume_dev_replace_async(fs_info);
+ ret = btrfs_start_pre_rw_mount(fs_info);
if (ret) {
- btrfs_warn(fs_info, "failed to resume device replace: %d", ret);
close_ctree(fs_info);
return ret;
}
- btrfs_qgroup_rescan_resume(fs_info);
-
- if (!fs_info->uuid_root) {
- btrfs_info(fs_info, "creating UUID tree");
- ret = btrfs_create_uuid_tree(fs_info);
- if (ret) {
- btrfs_warn(fs_info,
- "failed to create the UUID tree: %d", ret);
- close_ctree(fs_info);
- return ret;
- }
- } else if (btrfs_test_opt(fs_info, RESCAN_UUID_TREE) ||
- fs_info->generation !=
- btrfs_super_uuid_tree_generation(disk_super)) {
+ if (fs_info->uuid_root &&
+ (btrfs_test_opt(fs_info, RESCAN_UUID_TREE) ||
+ fs_info->generation != btrfs_super_uuid_tree_generation(disk_super))) {
btrfs_info(fs_info, "checking UUID tree");
ret = btrfs_check_uuid_tree(fs_info);
if (ret) {
diff --git a/fs/btrfs/disk-io.h b/fs/btrfs/disk-io.h
index 963163f14..714252a55 100644
--- a/fs/btrfs/disk-io.h
+++ b/fs/btrfs/disk-io.h
@@ -53,6 +53,7 @@ struct extent_buffer *btrfs_find_create_tree_block(
struct btrfs_fs_info *fs_info,
u64 bytenr);
void btrfs_clean_tree_block(struct extent_buffer *buf);
+int btrfs_start_pre_rw_mount(struct btrfs_fs_info *fs_info);
int __cold open_ctree(struct super_block *sb,
struct btrfs_fs_devices *fs_devices,
char *options);
diff --git a/fs/btrfs/super.c b/fs/btrfs/super.c
index 0caf7fbc2..c670b6e43 100644
--- a/fs/btrfs/super.c
+++ b/fs/btrfs/super.c
@@ -1726,7 +1726,6 @@ static inline void btrfs_remount_cleanup(struct btrfs_fs_info *fs_info,
static int btrfs_remount(struct super_block *sb, int *flags, char *data)
{
struct btrfs_fs_info *fs_info = btrfs_sb(sb);
- struct btrfs_root *root = fs_info->tree_root;
unsigned old_flags = sb->s_flags;
unsigned long old_opts = fs_info->mount_opt;
unsigned long old_compress_type = fs_info->compress_type;
@@ -1814,39 +1813,15 @@ static int btrfs_remount(struct super_block *sb, int *flags, char *data)
goto restore;
}
- ret = btrfs_cleanup_fs_roots(fs_info);
- if (ret)
- goto restore;
-
- /* recover relocation */
- mutex_lock(&fs_info->cleaner_mutex);
- ret = btrfs_recover_relocation(root);
- mutex_unlock(&fs_info->cleaner_mutex);
- if (ret)
- goto restore;
-
- ret = btrfs_resume_balance_async(fs_info);
+ /*
+ * NOTE: when remounting with a change that does writes, don't
+ * put it anywhere above this point, as we are not sure to be
+ * safe to write until we pass the above checks.
+ */
+ ret = btrfs_start_pre_rw_mount(fs_info);
if (ret)
goto restore;
- ret = btrfs_resume_dev_replace_async(fs_info);
- if (ret) {
- btrfs_warn(fs_info, "failed to resume dev_replace");
- goto restore;
- }
-
- btrfs_qgroup_rescan_resume(fs_info);
-
- if (!fs_info->uuid_root) {
- btrfs_info(fs_info, "creating UUID tree");
- ret = btrfs_create_uuid_tree(fs_info);
- if (ret) {
- btrfs_warn(fs_info,
- "failed to create the UUID tree %d",
- ret);
- goto restore;
- }
- }
sb->s_flags &= ~SB_RDONLY;
set_bit(BTRFS_FS_OPEN, &fs_info->flags);
--
2.26.2