Hello Jan,
> If qgroup tracking is out of sync, a rescan operation can be started. It
> iterates the complete extent tree and recalculates all qgroup tracking data.
> This is an expensive operation and should not be used unless required.
>
> A filesystem under rescan can still be umounted. The rescan continues on the
> next mount. Status information is provided with a separate ioctl while a
> rescan operation is in progress.
>
> Signed-off-by: Jan Schmidt <list.btrfs@xxxxxxxxxxxxx>
> ---
> fs/btrfs/ctree.h | 17 ++-
> fs/btrfs/disk-io.c | 5 +
> fs/btrfs/ioctl.c | 83 ++++++++++--
> fs/btrfs/qgroup.c | 312 ++++++++++++++++++++++++++++++++++++++++++--
> include/uapi/linux/btrfs.h | 12 ++-
> 5 files changed, 394 insertions(+), 35 deletions(-)
>
> diff --git a/fs/btrfs/ctree.h b/fs/btrfs/ctree.h
> index 412c306..e4f28a6 100644
> --- a/fs/btrfs/ctree.h
> +++ b/fs/btrfs/ctree.h
> @@ -1021,9 +1021,9 @@ struct btrfs_block_group_item {
> */
> #define BTRFS_QGROUP_STATUS_FLAG_ON (1ULL << 0)
> /*
> - * SCANNING is set during the initialization phase
> + * RESCAN is set during the initialization phase
> */
> -#define BTRFS_QGROUP_STATUS_FLAG_SCANNING (1ULL << 1)
> +#define BTRFS_QGROUP_STATUS_FLAG_RESCAN (1ULL << 1)
> /*
> * Some qgroup entries are known to be out of date,
> * either because the configuration has changed in a way that
> @@ -1052,7 +1052,7 @@ struct btrfs_qgroup_status_item {
> * only used during scanning to record the progress
> * of the scan. It contains a logical address
> */
> - __le64 scan;
> + __le64 rescan;
> } __attribute__ ((__packed__));
>
> struct btrfs_qgroup_info_item {
> @@ -1603,6 +1603,11 @@ struct btrfs_fs_info {
> /* used by btrfs_qgroup_record_ref for an efficient tree traversal */
> u64 qgroup_seq;
>
> + /* qgroup rescan items */
> + struct mutex qgroup_rescan_lock; /* protects the progress item */
> + struct btrfs_key qgroup_rescan_progress;
> + struct btrfs_workers qgroup_rescan_workers;
> +
> /* filesystem state */
> unsigned long fs_state;
>
> @@ -2888,8 +2893,8 @@ BTRFS_SETGET_FUNCS(qgroup_status_version, struct btrfs_qgroup_status_item,
> version, 64);
> BTRFS_SETGET_FUNCS(qgroup_status_flags, struct btrfs_qgroup_status_item,
> flags, 64);
> -BTRFS_SETGET_FUNCS(qgroup_status_scan, struct btrfs_qgroup_status_item,
> - scan, 64);
> +BTRFS_SETGET_FUNCS(qgroup_status_rescan, struct btrfs_qgroup_status_item,
> + rescan, 64);
>
> /* btrfs_qgroup_info_item */
> BTRFS_SETGET_FUNCS(qgroup_info_generation, struct btrfs_qgroup_info_item,
> @@ -3834,7 +3839,7 @@ int btrfs_quota_enable(struct btrfs_trans_handle *trans,
> struct btrfs_fs_info *fs_info);
> int btrfs_quota_disable(struct btrfs_trans_handle *trans,
> struct btrfs_fs_info *fs_info);
> -int btrfs_quota_rescan(struct btrfs_fs_info *fs_info);
> +int btrfs_qgroup_rescan(struct btrfs_fs_info *fs_info);
> int btrfs_add_qgroup_relation(struct btrfs_trans_handle *trans,
> struct btrfs_fs_info *fs_info, u64 src, u64 dst);
> int btrfs_del_qgroup_relation(struct btrfs_trans_handle *trans,
> diff --git a/fs/btrfs/disk-io.c b/fs/btrfs/disk-io.c
> index f4628c7..f80383e 100644
> --- a/fs/btrfs/disk-io.c
> +++ b/fs/btrfs/disk-io.c
> @@ -1996,6 +1996,7 @@ static void btrfs_stop_all_workers(struct btrfs_fs_info *fs_info)
> btrfs_stop_workers(&fs_info->caching_workers);
> btrfs_stop_workers(&fs_info->readahead_workers);
> btrfs_stop_workers(&fs_info->flush_workers);
> + btrfs_stop_workers(&fs_info->qgroup_rescan_workers);
> }
>
> /* helper to cleanup tree roots */
> @@ -2257,6 +2258,7 @@ int open_ctree(struct super_block *sb,
> fs_info->qgroup_seq = 1;
> fs_info->quota_enabled = 0;
> fs_info->pending_quota_state = 0;
> + mutex_init(&fs_info->qgroup_rescan_lock);
>
> btrfs_init_free_cluster(&fs_info->meta_alloc_cluster);
> btrfs_init_free_cluster(&fs_info->data_alloc_cluster);
> @@ -2485,6 +2487,8 @@ int open_ctree(struct super_block *sb,
> btrfs_init_workers(&fs_info->readahead_workers, "readahead",
> fs_info->thread_pool_size,
> &fs_info->generic_worker);
> + btrfs_init_workers(&fs_info->qgroup_rescan_workers, "qgroup-rescan", 1,
> + &fs_info->generic_worker);
>
> /*
> * endios are largely parallel and should have a very
> @@ -2519,6 +2523,7 @@ int open_ctree(struct super_block *sb,
> ret |= btrfs_start_workers(&fs_info->caching_workers);
> ret |= btrfs_start_workers(&fs_info->readahead_workers);
> ret |= btrfs_start_workers(&fs_info->flush_workers);
> + ret |= btrfs_start_workers(&fs_info->qgroup_rescan_workers);
> if (ret) {
> err = -ENOMEM;
> goto fail_sb_buffer;
> diff --git a/fs/btrfs/ioctl.c b/fs/btrfs/ioctl.c
> index d0af96a..5e93bb8 100644
> --- a/fs/btrfs/ioctl.c
> +++ b/fs/btrfs/ioctl.c
> @@ -3701,12 +3701,10 @@ static long btrfs_ioctl_quota_ctl(struct file *file, void __user *arg)
> }
>
> down_write(&root->fs_info->subvol_sem);
> - if (sa->cmd != BTRFS_QUOTA_CTL_RESCAN) {
> - trans = btrfs_start_transaction(root->fs_info->tree_root, 2);
> - if (IS_ERR(trans)) {
> - ret = PTR_ERR(trans);
> - goto out;
> - }
> + trans = btrfs_start_transaction(root->fs_info->tree_root, 2);
> + if (IS_ERR(trans)) {
> + ret = PTR_ERR(trans);
> + goto out;
> }
>
> switch (sa->cmd) {
> @@ -3716,9 +3714,6 @@ static long btrfs_ioctl_quota_ctl(struct file *file, void __user *arg)
> case BTRFS_QUOTA_CTL_DISABLE:
> ret = btrfs_quota_disable(trans, root->fs_info);
> break;
> - case BTRFS_QUOTA_CTL_RESCAN:
> - ret = btrfs_quota_rescan(root->fs_info);
> - break;
> default:
> ret = -EINVAL;
> break;
> @@ -3727,11 +3722,9 @@ static long btrfs_ioctl_quota_ctl(struct file *file, void __user *arg)
> if (copy_to_user(arg, sa, sizeof(*sa)))
> ret = -EFAULT;
>
> - if (trans) {
> - err = btrfs_commit_transaction(trans, root->fs_info->tree_root);
> - if (err && !ret)
> - ret = err;
> - }
> + err = btrfs_commit_transaction(trans, root->fs_info->tree_root);
> + if (err && !ret)
> + ret = err;
> out:
> kfree(sa);
> up_write(&root->fs_info->subvol_sem);
> @@ -3886,6 +3879,64 @@ drop_write:
> return ret;
> }
>
> +static long btrfs_ioctl_quota_rescan(struct file *file, void __user *arg)
> +{
> + struct btrfs_root *root = BTRFS_I(fdentry(file)->d_inode)->root;
> + struct btrfs_ioctl_quota_rescan_args *qsa;
> + int ret;
> +
> + if (!capable(CAP_SYS_ADMIN))
> + return -EPERM;
> +
> + ret = mnt_want_write_file(file);
> + if (ret)
> + return ret;
> +
> + qsa = memdup_user(arg, sizeof(*qsa));
> + if (IS_ERR(qsa)) {
> + ret = PTR_ERR(qsa);
> + goto drop_write;
> + }
> +
> + if (qsa->flags) {
> + ret = -EINVAL;
> + goto out;
> + }
> +
> + ret = btrfs_qgroup_rescan(root->fs_info);
> +
> +out:
> + kfree(qsa);
> +drop_write:
> + mnt_drop_write_file(file);
> + return ret;
> +}
> +
> +static long btrfs_ioctl_quota_rescan_status(struct file *file, void __user *arg)
> +{
> + struct btrfs_root *root = BTRFS_I(fdentry(file)->d_inode)->root;
> + struct btrfs_ioctl_quota_rescan_args *qsa;
> + int ret = 0;
> +
> + if (!capable(CAP_SYS_ADMIN))
> + return -EPERM;
> +
> + qsa = kzalloc(sizeof(*qsa), GFP_NOFS);
> + if (!qsa)
> + return -ENOMEM;
> +
> + if (root->fs_info->qgroup_flags & BTRFS_QGROUP_STATUS_FLAG_RESCAN) {
> + qsa->flags = 1;
> + qsa->progress = root->fs_info->qgroup_rescan_progress.objectid;
> + }
> +
> + if (copy_to_user(arg, qsa, sizeof(*qsa)))
> + ret = -EFAULT;
> +
> + kfree(qsa);
> + return ret;
> +}
> +
> static long btrfs_ioctl_set_received_subvol(struct file *file,
> void __user *arg)
> {
> @@ -4124,6 +4175,10 @@ long btrfs_ioctl(struct file *file, unsigned int
> return btrfs_ioctl_qgroup_create(file, argp);
> case BTRFS_IOC_QGROUP_LIMIT:
> return btrfs_ioctl_qgroup_limit(file, argp);
> + case BTRFS_IOC_QUOTA_RESCAN:
> + return btrfs_ioctl_quota_rescan(file, argp);
> + case BTRFS_IOC_QUOTA_RESCAN_STATUS:
> + return btrfs_ioctl_quota_rescan_status(file, argp);
> case BTRFS_IOC_DEV_REPLACE:
> return btrfs_ioctl_dev_replace(root, argp);
> case BTRFS_IOC_GET_FSLABEL:
> diff --git a/fs/btrfs/qgroup.c b/fs/btrfs/qgroup.c
> index c50e5a5..249dd64 100644
> --- a/fs/btrfs/qgroup.c
> +++ b/fs/btrfs/qgroup.c
> @@ -31,13 +31,13 @@
> #include "locking.h"
> #include "ulist.h"
> #include "backref.h"
> +#include "extent_io.h"
>
> /* TODO XXX FIXME
> * - subvol delete -> delete when ref goes to 0? delete limits also?
> * - reorganize keys
> * - compressed
> * - sync
> - * - rescan
> * - copy also limits on subvol creation
> * - limit
> * - caches fuer ulists
> @@ -98,6 +98,14 @@ struct btrfs_qgroup_list {
> struct btrfs_qgroup *member;
> };
>
> +struct qgroup_rescan {
> + struct btrfs_work work;
> + struct btrfs_fs_info *fs_info;
> +};
> +
> +static void qgroup_rescan_start(struct btrfs_fs_info *fs_info,
> + struct qgroup_rescan *qscan);
> +
> /* must be called with qgroup_ioctl_lock held */
> static struct btrfs_qgroup *find_qgroup_rb(struct btrfs_fs_info *fs_info,
> u64 qgroupid)
> @@ -298,7 +306,20 @@ int btrfs_read_qgroup_config(struct btrfs_fs_info *fs_info)
> }
> fs_info->qgroup_flags = btrfs_qgroup_status_flags(l,
> ptr);
> - /* FIXME read scan element */
> + fs_info->qgroup_rescan_progress.objectid =
> + btrfs_qgroup_status_rescan(l, ptr);
> + if (fs_info->qgroup_flags &
> + BTRFS_QGROUP_STATUS_FLAG_RESCAN) {
> + struct qgroup_rescan *qscan =
> + kmalloc(sizeof(*qscan), GFP_NOFS);
> + if (!qscan) {
> + ret = -ENOMEM;
> + goto out;
> + }
> + fs_info->qgroup_rescan_progress.type = 0;
> + fs_info->qgroup_rescan_progress.offset = 0;
> + qgroup_rescan_start(fs_info, qscan);
> + }
> goto next1;
> }
>
> @@ -717,9 +738,12 @@ static int update_qgroup_status_item(struct btrfs_trans_handle *trans,
> l = path->nodes[0];
> slot = path->slots[0];
> ptr = btrfs_item_ptr(l, slot, struct btrfs_qgroup_status_item);
> + spin_lock(&fs_info->qgroup_lock);
> btrfs_set_qgroup_status_flags(l, ptr, fs_info->qgroup_flags);
> btrfs_set_qgroup_status_generation(l, ptr, trans->transid);
> - /* XXX scan */
> + btrfs_set_qgroup_status_rescan(l, ptr,
> + fs_info->qgroup_rescan_progress.objectid);
> + spin_unlock(&fs_info->qgroup_lock);
Did you forget to remove spin lock 'qgroup_lock' here?...
Thanks,
Wang
[snip]
...
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