Jan Kara
2008-Oct-20 17:23 UTC
[Ocfs2-devel] [PATCH] quota: Implement function for scanning active dquots
OCFS2 needs to scan all active dquots once in a while and sync quota
information among cluster nodes. Provide a helper function for it so
that it does not have to reimplement internally a list which VFS
already has. Moreover this function is probably going to be useful
for other clustered filesystems if they decide to use VFS quotas.
Signed-off-by: Jan Kara <jack at suse.cz>
---
fs/dquot.c | 36 ++++++++++++++++++++++++++++++++++++
include/linux/quotaops.h | 3 +++
2 files changed, 39 insertions(+), 0 deletions(-)
diff --git a/fs/dquot.c b/fs/dquot.c
index c5016a2..0a4fcd0 100644
--- a/fs/dquot.c
+++ b/fs/dquot.c
@@ -478,6 +478,41 @@ restart:
spin_unlock(&dq_list_lock);
}
+/* Call callback for every active dquot on given filesystem */
+int dquot_scan_active(struct super_block *sb,
+ int (*fn)(struct dquot *dquot, unsigned long priv),
+ unsigned long priv)
+{
+ struct dquot *dquot, *old_dquot = NULL;
+ int ret = 0;
+
+ mutex_lock(&sb_dqopt(sb)->dqonoff_mutex);
+ spin_lock(&dq_list_lock);
+ list_for_each_entry(dquot, &inuse_list, dq_inuse) {
+ if (!test_bit(DQ_ACTIVE_B, &dquot->dq_flags))
+ continue;
+ if (dquot->dq_sb != sb)
+ continue;
+ /* Now we have active dquot so we can just increase use count */
+ atomic_inc(&dquot->dq_count);
+ dqstats.lookups++;
+ spin_unlock(&dq_list_lock);
+ dqput(old_dquot);
+ old_dquot = dquot;
+ ret = fn(dquot, priv);
+ if (ret < 0)
+ goto out;
+ spin_lock(&dq_list_lock);
+ /* We are safe to continue now because our dquot could not
+ * be moved out of the inuse list while we hold the reference */
+ }
+ spin_unlock(&dq_list_lock);
+out:
+ dqput(old_dquot);
+ mutex_unlock(&sb_dqopt(sb)->dqonoff_mutex);
+ return ret;
+}
+
int vfs_quota_sync(struct super_block *sb, int type)
{
struct list_head *dirty;
@@ -2318,6 +2353,7 @@ EXPORT_SYMBOL(vfs_quota_on_path);
EXPORT_SYMBOL(vfs_quota_on_mount);
EXPORT_SYMBOL(vfs_quota_disable);
EXPORT_SYMBOL(vfs_quota_off);
+EXPORT_SYMBOL(dquot_scan_active);
EXPORT_SYMBOL(vfs_quota_sync);
EXPORT_SYMBOL(vfs_get_dqinfo);
EXPORT_SYMBOL(vfs_set_dqinfo);
diff --git a/include/linux/quotaops.h b/include/linux/quotaops.h
index 4cb298d..f504e64 100644
--- a/include/linux/quotaops.h
+++ b/include/linux/quotaops.h
@@ -29,6 +29,9 @@ int dquot_initialize(struct inode *inode, int type);
int dquot_drop(struct inode *inode);
int dquot_drop_locked(struct inode *inode);
int dquot_is_cached(struct super_block *sb, unsigned int id, int type);
+int dquot_scan_active(struct super_block *sb,
+ int (*fn)(struct dquot *dquot, unsigned long priv),
+ unsigned long priv);
int dquot_alloc_space(struct inode *inode, qsize_t number, int prealloc);
int dquot_alloc_inode(const struct inode *inode, qsize_t number);
--
1.5.2.4