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authorJan Schmidt <list.btrfs@jan-o-sch.net>2013-05-28 15:47:24 +0000
committerJosef Bacik <jbacik@fusionio.com>2013-06-14 11:30:10 -0400
commitb382a324b60f4923e9fc8e11f023e4f493c51318 (patch)
tree4f93e6d8a6671abbd240df83ee49f972e212bc4b
parenteb1716af887375f1e2099f69bb89dfc5bd169bfa (diff)
Btrfs: fix qgroup rescan resume on mount
When called during mount, we cannot start the rescan worker thread until open_ctree is done. This commit restuctures the qgroup rescan internals to enable a clean deferral of the rescan resume operation. First of all, the struct qgroup_rescan is removed, saving us a malloc and some initialization synchronizations problems. Its only element (the worker struct) now lives within fs_info just as the rest of the rescan code. Then setting up a rescan worker is split into several reusable stages. Currently we have three different rescan startup scenarios: (A) rescan ioctl (B) rescan resume by mount (C) rescan by quota enable Each case needs its own combination of the four following steps: (1) set the progress [A, C: zero; B: state of umount] (2) commit the transaction [A] (3) set the counters [A, C: zero; B: state of umount] (4) start worker [A, B, C] qgroup_rescan_init does step (1). There's no extra function added to commit a transaction, we've got that already. qgroup_rescan_zero_tracking does step (3). Step (4) is nothing more than a call to the generic btrfs_queue_worker. We also get rid of a double check for the rescan progress during btrfs_qgroup_account_ref, which is no longer required due to having step 2 from the list above. As a side effect, this commit prepares to move the rescan start code from btrfs_run_qgroups (which is run during commit) to a less time critical section. Signed-off-by: Jan Schmidt <list.btrfs@jan-o-sch.net> Signed-off-by: Josef Bacik <jbacik@fusionio.com>
-rw-r--r--fs/btrfs/ctree.h2
-rw-r--r--fs/btrfs/disk-io.c2
-rw-r--r--fs/btrfs/qgroup.c190
3 files changed, 125 insertions, 69 deletions
diff --git a/fs/btrfs/ctree.h b/fs/btrfs/ctree.h
index a07b8c0a260d..80ab1a6f4fe3 100644
--- a/fs/btrfs/ctree.h
+++ b/fs/btrfs/ctree.h
@@ -1609,6 +1609,7 @@ struct btrfs_fs_info {
struct btrfs_key qgroup_rescan_progress;
struct btrfs_workers qgroup_rescan_workers;
struct completion qgroup_rescan_completion;
+ struct btrfs_work qgroup_rescan_work;
/* filesystem state */
unsigned long fs_state;
@@ -3858,6 +3859,7 @@ int btrfs_quota_enable(struct btrfs_trans_handle *trans,
int btrfs_quota_disable(struct btrfs_trans_handle *trans,
struct btrfs_fs_info *fs_info);
int btrfs_qgroup_rescan(struct btrfs_fs_info *fs_info);
+void btrfs_qgroup_rescan_resume(struct btrfs_fs_info *fs_info);
int btrfs_qgroup_wait_for_completion(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);
diff --git a/fs/btrfs/disk-io.c b/fs/btrfs/disk-io.c
index b9eaa0f21144..9b7020197c71 100644
--- a/fs/btrfs/disk-io.c
+++ b/fs/btrfs/disk-io.c
@@ -2879,6 +2879,8 @@ retry_root_backup:
return ret;
}
+ btrfs_qgroup_rescan_resume(fs_info);
+
return 0;
fail_qgroup:
diff --git a/fs/btrfs/qgroup.c b/fs/btrfs/qgroup.c
index c6ce64276869..1280eff8af56 100644
--- a/fs/btrfs/qgroup.c
+++ b/fs/btrfs/qgroup.c
@@ -98,13 +98,10 @@ 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);
+static int
+qgroup_rescan_init(struct btrfs_fs_info *fs_info, u64 progress_objectid,
+ int init_flags);
+static void qgroup_rescan_zero_tracking(struct btrfs_fs_info *fs_info);
/* must be called with qgroup_ioctl_lock held */
static struct btrfs_qgroup *find_qgroup_rb(struct btrfs_fs_info *fs_info,
@@ -255,6 +252,7 @@ int btrfs_read_qgroup_config(struct btrfs_fs_info *fs_info)
int slot;
int ret = 0;
u64 flags = 0;
+ u64 rescan_progress = 0;
if (!fs_info->quota_enabled)
return 0;
@@ -312,20 +310,7 @@ int btrfs_read_qgroup_config(struct btrfs_fs_info *fs_info)
}
fs_info->qgroup_flags = btrfs_qgroup_status_flags(l,
ptr);
- 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);
- }
+ rescan_progress = btrfs_qgroup_status_rescan(l, ptr);
goto next1;
}
@@ -427,12 +412,16 @@ out:
if (!(fs_info->qgroup_flags & BTRFS_QGROUP_STATUS_FLAG_ON)) {
fs_info->quota_enabled = 0;
fs_info->pending_quota_state = 0;
+ } else if (fs_info->qgroup_flags & BTRFS_QGROUP_STATUS_FLAG_RESCAN &&
+ ret >= 0) {
+ ret = qgroup_rescan_init(fs_info, rescan_progress, 0);
}
btrfs_free_path(path);
if (ret < 0) {
ulist_free(fs_info->qgroup_ulist);
fs_info->qgroup_ulist = NULL;
+ fs_info->qgroup_flags &= ~BTRFS_QGROUP_STATUS_FLAG_RESCAN;
}
return ret < 0 ? ret : 0;
@@ -1449,14 +1438,7 @@ int btrfs_qgroup_account_ref(struct btrfs_trans_handle *trans,
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)
@@ -1496,7 +1478,6 @@ int btrfs_qgroup_account_ref(struct btrfs_trans_handle *trans,
unlock:
spin_unlock(&fs_info->qgroup_lock);
- mutex_unlock(&fs_info->qgroup_rescan_lock);
ulist_free(roots);
return ret;
@@ -1544,9 +1525,12 @@ int btrfs_run_qgroups(struct btrfs_trans_handle *trans,
fs_info->qgroup_flags |= BTRFS_QGROUP_STATUS_FLAG_INCONSISTENT;
if (!ret && start_rescan_worker) {
- ret = btrfs_qgroup_rescan(fs_info);
- if (ret)
- pr_err("btrfs: start rescan quota failed: %d\n", ret);
+ ret = qgroup_rescan_init(fs_info, 0, 1);
+ if (!ret) {
+ qgroup_rescan_zero_tracking(fs_info);
+ btrfs_queue_worker(&fs_info->qgroup_rescan_workers,
+ &fs_info->qgroup_rescan_work);
+ }
ret = 0;
}
@@ -1880,12 +1864,11 @@ void assert_qgroups_uptodate(struct btrfs_trans_handle *trans)
* 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,
+qgroup_rescan_leaf(struct btrfs_fs_info *fs_info, 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;
@@ -2013,11 +1996,10 @@ out:
static void btrfs_qgroup_rescan_worker(struct btrfs_work *work)
{
- struct qgroup_rescan *qscan = container_of(work, struct qgroup_rescan,
- work);
+ struct btrfs_fs_info *fs_info = container_of(work, struct btrfs_fs_info,
+ 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;
@@ -2042,7 +2024,7 @@ static void btrfs_qgroup_rescan_worker(struct btrfs_work *work)
if (!fs_info->quota_enabled) {
err = -EINTR;
} else {
- err = qgroup_rescan_leaf(qscan, path, trans,
+ err = qgroup_rescan_leaf(fs_info, path, trans,
tmp, scratch_leaf);
}
if (err > 0)
@@ -2055,7 +2037,6 @@ 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;
@@ -2078,46 +2059,70 @@ out:
complete_all(&fs_info->qgroup_rescan_completion);
}
-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)
+/*
+ * Checks that (a) no rescan is running and (b) quota is enabled. Allocates all
+ * memory required for the rescan context.
+ */
+static int
+qgroup_rescan_init(struct btrfs_fs_info *fs_info, u64 progress_objectid,
+ int init_flags)
{
int ret = 0;
- struct rb_node *n;
- struct btrfs_qgroup *qgroup;
- struct qgroup_rescan *qscan = kmalloc(sizeof(*qscan), GFP_NOFS);
- if (!qscan)
- return -ENOMEM;
+ if (!init_flags &&
+ (!(fs_info->qgroup_flags & BTRFS_QGROUP_STATUS_FLAG_RESCAN) ||
+ !(fs_info->qgroup_flags & BTRFS_QGROUP_STATUS_FLAG_ON))) {
+ ret = -EINVAL;
+ goto err;
+ }
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;
+
+ if (init_flags) {
+ 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);
+ goto err;
+ }
+
+ fs_info->qgroup_flags |= BTRFS_QGROUP_STATUS_FLAG_RESCAN;
}
- fs_info->qgroup_flags |= BTRFS_QGROUP_STATUS_FLAG_RESCAN;
memset(&fs_info->qgroup_rescan_progress, 0,
sizeof(fs_info->qgroup_rescan_progress));
+ fs_info->qgroup_rescan_progress.objectid = progress_objectid;
+
+ spin_unlock(&fs_info->qgroup_lock);
+ mutex_unlock(&fs_info->qgroup_rescan_lock);
+
init_completion(&fs_info->qgroup_rescan_completion);
+ memset(&fs_info->qgroup_rescan_work, 0,
+ sizeof(fs_info->qgroup_rescan_work));
+ fs_info->qgroup_rescan_work.func = btrfs_qgroup_rescan_worker;
+
+ if (ret) {
+err:
+ pr_info("btrfs: qgroup_rescan_init failed with %d\n", ret);
+ return ret;
+ }
+
+ return 0;
+}
+
+static void
+qgroup_rescan_zero_tracking(struct btrfs_fs_info *fs_info)
+{
+ struct rb_node *n;
+ struct btrfs_qgroup *qgroup;
+
+ spin_lock(&fs_info->qgroup_lock);
/* 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);
@@ -2127,9 +2132,44 @@ btrfs_qgroup_rescan(struct btrfs_fs_info *fs_info)
qgroup->excl_cmpr = 0;
}
spin_unlock(&fs_info->qgroup_lock);
- mutex_unlock(&fs_info->qgroup_rescan_lock);
+}
- qgroup_rescan_start(fs_info, qscan);
+int
+btrfs_qgroup_rescan(struct btrfs_fs_info *fs_info)
+{
+ int ret = 0;
+ struct btrfs_trans_handle *trans;
+
+ ret = qgroup_rescan_init(fs_info, 0, 1);
+ if (ret)
+ return ret;
+
+ /*
+ * We have set the rescan_progress to 0, which means no more
+ * delayed refs will be accounted by btrfs_qgroup_account_ref.
+ * However, btrfs_qgroup_account_ref may be right after its call
+ * to btrfs_find_all_roots, in which case it would still do the
+ * accounting.
+ * To solve this, we're committing the transaction, which will
+ * ensure we run all delayed refs and only after that, we are
+ * going to clear all tracking information for a clean start.
+ */
+
+ trans = btrfs_join_transaction(fs_info->fs_root);
+ if (IS_ERR(trans)) {
+ fs_info->qgroup_flags &= ~BTRFS_QGROUP_STATUS_FLAG_RESCAN;
+ return PTR_ERR(trans);
+ }
+ ret = btrfs_commit_transaction(trans, fs_info->fs_root);
+ if (ret) {
+ fs_info->qgroup_flags &= ~BTRFS_QGROUP_STATUS_FLAG_RESCAN;
+ return ret;
+ }
+
+ qgroup_rescan_zero_tracking(fs_info);
+
+ btrfs_queue_worker(&fs_info->qgroup_rescan_workers,
+ &fs_info->qgroup_rescan_work);
return 0;
}
@@ -2151,3 +2191,15 @@ int btrfs_qgroup_wait_for_completion(struct btrfs_fs_info *fs_info)
return ret;
}
+
+/*
+ * this is only called from open_ctree where we're still single threaded, thus
+ * locking is omitted here.
+ */
+void
+btrfs_qgroup_rescan_resume(struct btrfs_fs_info *fs_info)
+{
+ if (fs_info->qgroup_flags & BTRFS_QGROUP_STATUS_FLAG_RESCAN)
+ btrfs_queue_worker(&fs_info->qgroup_rescan_workers,
+ &fs_info->qgroup_rescan_work);
+}