From 83273932fbefb6ceef9c0b82ac4d23900728f4d9 Mon Sep 17 00:00:00 2001 From: Srinivas Eeda Date: Wed, 3 Jun 2009 17:02:55 -0700 Subject: ocfs2: timer to queue scan of all orphan slots When a dentry is unlinked, the unlinking node takes an EX on the dentry lock before moving the dentry to the orphan directory. Other nodes that have this dentry in cache have a PR on the same dentry lock. When the EX is requested, the other nodes flag the corresponding inode as MAYBE_ORPHANED during downconvert. The inode is finally deleted when the last node to iput the inode sees that i_nlink==0 and the MAYBE_ORPHANED flag is set. A problem arises if a node is forced to free dentry locks because of memory pressure. If this happens, the node will no longer get downconvert notifications for the dentries that have been unlinked on another node. If it also happens that node is actively using the corresponding inode and happens to be the one performing the last iput on that inode, it will fail to delete the inode as it will not have the MAYBE_ORPHANED flag set. This patch fixes this shortcoming by introducing a periodic scan of the orphan directories to delete such inodes. Care has been taken to distribute the workload across the cluster so that no one node has to perform the task all the time. Signed-off-by: Srinivas Eeda Signed-off-by: Joel Becker --- fs/ocfs2/ocfs2.h | 10 ++++++++++ 1 file changed, 10 insertions(+) (limited to 'fs/ocfs2/ocfs2.h') diff --git a/fs/ocfs2/ocfs2.h b/fs/ocfs2/ocfs2.h index 1386281950d..1fde52c96d2 100644 --- a/fs/ocfs2/ocfs2.h +++ b/fs/ocfs2/ocfs2.h @@ -151,6 +151,14 @@ struct ocfs2_lock_res { #endif }; +struct ocfs2_orphan_scan { + struct mutex os_lock; + struct ocfs2_super *os_osb; + struct ocfs2_lock_res os_lockres; /* lock to synchronize scans */ + struct delayed_work os_orphan_scan_work; + u32 os_seqno; /* incremented on every scan */ +}; + struct ocfs2_dlm_debug { struct kref d_refcnt; struct dentry *d_locking_state; @@ -341,6 +349,8 @@ struct ocfs2_super unsigned int *osb_orphan_wipes; wait_queue_head_t osb_wipe_event; + struct ocfs2_orphan_scan osb_orphan_scan; + /* used to protect metaecc calculation check of xattr. */ spinlock_t osb_xattr_lock; -- cgit v1.2.3