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btrfs: lift read-write mount setup from mount and remount

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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>
This commit is contained in:
Boris Burkov 2020-11-18 15:06:16 -08:00 committed by David Sterba
parent 47876f7cef
commit 44c0ca211a
3 changed files with 57 additions and 70 deletions
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89
fs/btrfs/disk-io.c
View file

@ -2870,6 +2870,52 @@ static int btrfs_check_uuid_tree(struct btrfs_fs_info *fs_info)
return 0;
}
/*
* 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)
{
@ -3285,22 +3331,6 @@ 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;
}
}
fs_info->fs_root = btrfs_get_fs_root(fs_info, BTRFS_FS_TREE_OBJECTID, true);
if (IS_ERR(fs_info->fs_root)) {
err = PTR_ERR(fs_info->fs_root);
@ -3353,35 +3383,16 @@ 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);
ret = btrfs_start_pre_rw_mount(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);
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);
btrfs_discard_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) {

1
fs/btrfs/disk-io.h
View file

@ -50,6 +50,7 @@ struct extent_buffer *btrfs_find_create_tree_block(
u64 bytenr, u64 owner_root,
int level);
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);

37
fs/btrfs/super.c
View file

@ -1885,7 +1885,6 @@ 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;
@ -1978,39 +1977,15 @@ static int btrfs_remount(struct super_block *sb, int *flags, char *data)
goto restore;
}
ret = btrfs_cleanup_fs_roots(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;
/* 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);
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);