Btrfs: rescan for qgroups
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@jan-o-sch.net>
Signed-off-by: Josef Bacik <jbacik@fusionio.com>
diff --git a/fs/btrfs/ctree.h b/fs/btrfs/ctree.h
index 2c48f52..d9bed5f 100644
--- a/fs/btrfs/ctree.h
+++ b/fs/btrfs/ctree.h
@@ -1021,9 +1021,9 @@
*/
#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* Some qgroup entries are known to be out of date,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 @@
* 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 @@
/* 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;
@@ -2886,8 +2891,8 @@
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,
@@ -3828,7 +3833,7 @@
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 92c44ed..d96305e 100644
--- a/fs/btrfs/disk-io.c
+++ b/fs/btrfs/disk-io.c
@@ -1976,6 +1976,7 @@
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 */
@@ -2267,6 +2268,7 @@
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);
@@ -2476,6 +2478,8 @@
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
@@ -2510,6 +2514,7 @@
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 a74edc7..f5f6af3 100644
--- a/fs/btrfs/ioctl.c
+++ b/fs/btrfs/ioctl.c
@@ -3701,12 +3701,10 @@
}
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 @@
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 @@
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 @@
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 @@
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 1fb7d8d..da84583 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 *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 @@
}
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;
}
@@ -719,7 +740,8 @@
ptr = btrfs_item_ptr(l, slot, struct btrfs_qgroup_status_item);
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);
btrfs_mark_buffer_dirty(l);
@@ -830,7 +852,7 @@
fs_info->qgroup_flags = BTRFS_QGROUP_STATUS_FLAG_ON |
BTRFS_QGROUP_STATUS_FLAG_INCONSISTENT;
btrfs_set_qgroup_status_flags(leaf, ptr, fs_info->qgroup_flags);
- btrfs_set_qgroup_status_scan(leaf, ptr, 0);
+ btrfs_set_qgroup_status_rescan(leaf, ptr, 0);
btrfs_mark_buffer_dirty(leaf);
@@ -944,10 +966,11 @@
return ret;
}
-int btrfs_quota_rescan(struct btrfs_fs_info *fs_info)
+static void qgroup_dirty(struct btrfs_fs_info *fs_info,
+ struct btrfs_qgroup *qgroup)
{
- /* FIXME */
- return 0;
+ if (list_empty(&qgroup->dirty))
+ list_add(&qgroup->dirty, &fs_info->dirty_qgroups);
}
int btrfs_add_qgroup_relation(struct btrfs_trans_handle *trans,
@@ -1155,13 +1178,6 @@
return ret;
}
-static void qgroup_dirty(struct btrfs_fs_info *fs_info,
- struct btrfs_qgroup *qgroup)
-{
- if (list_empty(&qgroup->dirty))
- list_add(&qgroup->dirty, &fs_info->dirty_qgroups);
-}
-
/*
* btrfs_qgroup_record_ref is called when the ref is added or deleted. it puts
* the modification into a list that's later used by btrfs_end_transaction to
@@ -1390,6 +1406,15 @@
BUG();
}
+ mutex_lock(&fs_info->qgroup_rescan_lock);
+ if (fs_info->qgroup_flags & BTRFS_QGROUP_STATUS_FLAG_RESCAN) {
+ if (fs_info->qgroup_rescan_progress.objectid <= node->bytenr) {
+ mutex_unlock(&fs_info->qgroup_rescan_lock);
+ return 0;
+ }
+ }
+ mutex_unlock(&fs_info->qgroup_rescan_lock);
+
/*
* the delayed ref sequence number we pass depends on the direction of
* the operation. for add operations, we pass
@@ -1403,7 +1428,15 @@
if (ret < 0)
return ret;
+ mutex_lock(&fs_info->qgroup_rescan_lock);
spin_lock(&fs_info->qgroup_lock);
+ if (fs_info->qgroup_flags & BTRFS_QGROUP_STATUS_FLAG_RESCAN) {
+ if (fs_info->qgroup_rescan_progress.objectid <= node->bytenr) {
+ ret = 0;
+ goto unlock;
+ }
+ }
+
quota_root = fs_info->quota_root;
if (!quota_root)
goto unlock;
@@ -1445,6 +1478,7 @@
unlock:
spin_unlock(&fs_info->qgroup_lock);
+ mutex_unlock(&fs_info->qgroup_rescan_lock);
ulist_free(roots);
ulist_free(tmp);
@@ -1823,3 +1857,259 @@
(u32)trans->delayed_ref_elem.seq);
BUG();
}
+
+/*
+ * returns < 0 on error, 0 when more leafs are to be scanned.
+ * returns 1 when done, 2 when done and FLAG_INCONSISTENT was cleared.
+ */
+static int
+qgroup_rescan_leaf(struct qgroup_rescan *qscan, struct btrfs_path *path,
+ struct btrfs_trans_handle *trans, struct ulist *tmp,
+ struct extent_buffer *scratch_leaf)
+{
+ struct btrfs_key found;
+ struct btrfs_fs_info *fs_info = qscan->fs_info;
+ struct ulist *roots = NULL;
+ struct ulist_node *unode;
+ struct ulist_iterator uiter;
+ struct seq_list tree_mod_seq_elem = {};
+ u64 seq;
+ int slot;
+ int ret;
+
+ path->leave_spinning = 1;
+ mutex_lock(&fs_info->qgroup_rescan_lock);
+ ret = btrfs_search_slot_for_read(fs_info->extent_root,
+ &fs_info->qgroup_rescan_progress,
+ path, 1, 0);
+
+ pr_debug("current progress key (%llu %u %llu), search_slot ret %d\n",
+ (unsigned long long)fs_info->qgroup_rescan_progress.objectid,
+ fs_info->qgroup_rescan_progress.type,
+ (unsigned long long)fs_info->qgroup_rescan_progress.offset,
+ ret);
+
+ if (ret) {
+ /*
+ * The rescan is about to end, we will not be scanning any
+ * further blocks. We cannot unset the RESCAN flag here, because
+ * we want to commit the transaction if everything went well.
+ * To make the live accounting work in this phase, we set our
+ * scan progress pointer such that every real extent objectid
+ * will be smaller.
+ */
+ fs_info->qgroup_rescan_progress.objectid = (u64)-1;
+ btrfs_release_path(path);
+ mutex_unlock(&fs_info->qgroup_rescan_lock);
+ return ret;
+ }
+
+ btrfs_item_key_to_cpu(path->nodes[0], &found,
+ btrfs_header_nritems(path->nodes[0]) - 1);
+ fs_info->qgroup_rescan_progress.objectid = found.objectid + 1;
+
+ btrfs_get_tree_mod_seq(fs_info, &tree_mod_seq_elem);
+ memcpy(scratch_leaf, path->nodes[0], sizeof(*scratch_leaf));
+ slot = path->slots[0];
+ btrfs_release_path(path);
+ mutex_unlock(&fs_info->qgroup_rescan_lock);
+
+ for (; slot < btrfs_header_nritems(scratch_leaf); ++slot) {
+ btrfs_item_key_to_cpu(scratch_leaf, &found, slot);
+ if (found.type != BTRFS_EXTENT_ITEM_KEY)
+ continue;
+ ret = btrfs_find_all_roots(trans, fs_info, found.objectid,
+ tree_mod_seq_elem.seq, &roots);
+ if (ret < 0)
+ goto out;
+ spin_lock(&fs_info->qgroup_lock);
+ seq = fs_info->qgroup_seq;
+ fs_info->qgroup_seq += roots->nnodes + 1; /* max refcnt */
+
+ ret = qgroup_account_ref_step1(fs_info, roots, tmp, seq);
+ if (ret) {
+ spin_unlock(&fs_info->qgroup_lock);
+ ulist_free(roots);
+ goto out;
+ }
+
+ /*
+ * step2 of btrfs_qgroup_account_ref works from a single root,
+ * we're doing all at once here.
+ */
+ ulist_reinit(tmp);
+ ULIST_ITER_INIT(&uiter);
+ while ((unode = ulist_next(roots, &uiter))) {
+ struct btrfs_qgroup *qg;
+
+ qg = find_qgroup_rb(fs_info, unode->val);
+ if (!qg)
+ continue;
+
+ ret = ulist_add(tmp, qg->qgroupid, (uintptr_t)qg,
+ GFP_ATOMIC);
+ if (ret < 0) {
+ spin_unlock(&fs_info->qgroup_lock);
+ ulist_free(roots);
+ goto out;
+ }
+ }
+
+ /* this loop is similar to step 2 of btrfs_qgroup_account_ref */
+ ULIST_ITER_INIT(&uiter);
+ while ((unode = ulist_next(tmp, &uiter))) {
+ struct btrfs_qgroup *qg;
+ struct btrfs_qgroup_list *glist;
+
+ qg = (struct btrfs_qgroup *)(uintptr_t) unode->aux;
+ qg->rfer += found.offset;
+ qg->rfer_cmpr += found.offset;
+ WARN_ON(qg->tag >= seq);
+ if (qg->refcnt - seq == roots->nnodes) {
+ qg->excl += found.offset;
+ qg->excl_cmpr += found.offset;
+ }
+ qgroup_dirty(fs_info, qg);
+
+ list_for_each_entry(glist, &qg->groups, next_group) {
+ ret = ulist_add(tmp, glist->group->qgroupid,
+ (uintptr_t)glist->group,
+ GFP_ATOMIC);
+ if (ret < 0) {
+ spin_unlock(&fs_info->qgroup_lock);
+ ulist_free(roots);
+ goto out;
+ }
+ }
+ }
+
+ spin_unlock(&fs_info->qgroup_lock);
+ ulist_free(roots);
+ ret = 0;
+ }
+
+out:
+ btrfs_put_tree_mod_seq(fs_info, &tree_mod_seq_elem);
+
+ return ret;
+}
+
+static void btrfs_qgroup_rescan_worker(struct btrfs_work *work)
+{
+ struct qgroup_rescan *qscan = container_of(work, struct qgroup_rescan,
+ work);
+ struct btrfs_path *path;
+ struct btrfs_trans_handle *trans = NULL;
+ struct btrfs_fs_info *fs_info = qscan->fs_info;
+ struct ulist *tmp = NULL;
+ struct extent_buffer *scratch_leaf = NULL;
+ int err = -ENOMEM;
+
+ path = btrfs_alloc_path();
+ if (!path)
+ goto out;
+ tmp = ulist_alloc(GFP_NOFS);
+ if (!tmp)
+ goto out;
+ scratch_leaf = kmalloc(sizeof(*scratch_leaf), GFP_NOFS);
+ if (!scratch_leaf)
+ goto out;
+
+ err = 0;
+ while (!err) {
+ trans = btrfs_start_transaction(fs_info->fs_root, 0);
+ if (IS_ERR(trans)) {
+ err = PTR_ERR(trans);
+ break;
+ }
+ if (!fs_info->quota_enabled) {
+ err = -EINTR;
+ } else {
+ err = qgroup_rescan_leaf(qscan, path, trans,
+ tmp, scratch_leaf);
+ }
+ if (err > 0)
+ btrfs_commit_transaction(trans, fs_info->fs_root);
+ else
+ btrfs_end_transaction(trans, fs_info->fs_root);
+ }
+
+out:
+ kfree(scratch_leaf);
+ ulist_free(tmp);
+ btrfs_free_path(path);
+ kfree(qscan);
+
+ mutex_lock(&fs_info->qgroup_rescan_lock);
+ fs_info->qgroup_flags &= ~BTRFS_QGROUP_STATUS_FLAG_RESCAN;
+
+ if (err == 2 &&
+ fs_info->qgroup_flags & BTRFS_QGROUP_STATUS_FLAG_INCONSISTENT) {
+ fs_info->qgroup_flags &= ~BTRFS_QGROUP_STATUS_FLAG_INCONSISTENT;
+ } else if (err < 0) {
+ fs_info->qgroup_flags |= BTRFS_QGROUP_STATUS_FLAG_INCONSISTENT;
+ }
+ mutex_unlock(&fs_info->qgroup_rescan_lock);
+
+ if (err >= 0) {
+ pr_info("btrfs: qgroup scan completed%s\n",
+ err == 2 ? " (inconsistency flag cleared)" : "");
+ } else {
+ pr_err("btrfs: qgroup scan failed with %d\n", err);
+ }
+}
+
+static void
+qgroup_rescan_start(struct btrfs_fs_info *fs_info, struct qgroup_rescan *qscan)
+{
+ memset(&qscan->work, 0, sizeof(qscan->work));
+ qscan->work.func = btrfs_qgroup_rescan_worker;
+ qscan->fs_info = fs_info;
+
+ pr_info("btrfs: qgroup scan started\n");
+ btrfs_queue_worker(&fs_info->qgroup_rescan_workers, &qscan->work);
+}
+
+int
+btrfs_qgroup_rescan(struct btrfs_fs_info *fs_info)
+{
+ int ret = 0;
+ struct rb_node *n;
+ struct btrfs_qgroup *qgroup;
+ struct qgroup_rescan *qscan = kmalloc(sizeof(*qscan), GFP_NOFS);
+
+ if (!qscan)
+ return -ENOMEM;
+
+ mutex_lock(&fs_info->qgroup_rescan_lock);
+ spin_lock(&fs_info->qgroup_lock);
+ if (fs_info->qgroup_flags & BTRFS_QGROUP_STATUS_FLAG_RESCAN)
+ ret = -EINPROGRESS;
+ else if (!(fs_info->qgroup_flags & BTRFS_QGROUP_STATUS_FLAG_ON))
+ ret = -EINVAL;
+ if (ret) {
+ spin_unlock(&fs_info->qgroup_lock);
+ mutex_unlock(&fs_info->qgroup_rescan_lock);
+ kfree(qscan);
+ return ret;
+ }
+
+ fs_info->qgroup_flags |= BTRFS_QGROUP_STATUS_FLAG_RESCAN;
+ memset(&fs_info->qgroup_rescan_progress, 0,
+ sizeof(fs_info->qgroup_rescan_progress));
+
+ /* clear all current qgroup tracking information */
+ for (n = rb_first(&fs_info->qgroup_tree); n; n = rb_next(n)) {
+ qgroup = rb_entry(n, struct btrfs_qgroup, node);
+ qgroup->rfer = 0;
+ qgroup->rfer_cmpr = 0;
+ qgroup->excl = 0;
+ qgroup->excl_cmpr = 0;
+ }
+ spin_unlock(&fs_info->qgroup_lock);
+ mutex_unlock(&fs_info->qgroup_rescan_lock);
+
+ qgroup_rescan_start(fs_info, qscan);
+
+ return 0;
+}
