[PATCH] knfsd: lockd: make nlm_traverse_* more flexible

This patch makes nlm_traverse{locks,blocks,shares} and friends use a function
pointer rather than a "action" enum.

This function pointer is given two nlm_hosts (one given by the caller, the
other taken from the lock/block/share currently visited), and is free to do
with them as it wants.  If it returns a non-zero value, the lockd/block/share
is released.

Signed-off-by: Olaf Kirch <okir@suse.de>
Signed-off-by: Neil Brown <neilb@suse.de>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>

3 files changed, 93 insertions, 65 deletions

diff --git a/fs/lockd/svclock.c b/fs/lockd/svclock.c
index 7209712f3832..1f91567a1b88 100644
--- a/fs/lockd/svclock.c
+++ b/fs/lockd/svclock.c
@@ -265,24 +265,20 @@ static void nlmsvc_release_block(struct nlm_block *block)
                 kref_put(&block->b_count, nlmsvc_free_block);
 }
 
-static void nlmsvc_act_mark(struct nlm_host *host, struct nlm_file *file)
-{
-        struct nlm_block *block;
-
-        down(&file->f_sema);
-        list_for_each_entry(block, &file->f_blocks, b_flist)
-                block->b_host->h_inuse = 1;
-        up(&file->f_sema);
-}
-
-static void nlmsvc_act_unlock(struct nlm_host *host, struct nlm_file *file)
+/*
+ * Loop over all blocks and delete blocks held by
+ * a matching host.
+ */
+void nlmsvc_traverse_blocks(struct nlm_host *host,
+                        struct nlm_file *file,
+                        nlm_host_match_fn_t match)
 {
         struct nlm_block *block, *next;
 
 restart:
         down(&file->f_sema);
         list_for_each_entry_safe(block, next, &file->f_blocks, b_flist) {
-                if (host != NULL && host != block->b_host)
+                if (!match(block->b_host, host))
                         continue;
                 /* Do not destroy blocks that are not on
                  * the global retry list - why? */
@@ -298,19 +294,6 @@ restart:
 }
 
 /*
- * Loop over all blocks and perform the action specified.
- * (NLM_ACT_CHECK handled by nlmsvc_inspect_file).
- */
-void
-nlmsvc_traverse_blocks(struct nlm_host *host, struct nlm_file *file, int action)
-{
-        if (action == NLM_ACT_MARK)
-                nlmsvc_act_mark(host, file);
-        else
-                nlmsvc_act_unlock(host, file);
-}
-
-/*
  * Initialize arguments for GRANTED call. The nlm_rqst structure
  * has been cleared already.
  */
diff --git a/fs/lockd/svcshare.c b/fs/lockd/svcshare.c
index 27288c83da96..b9926ce8782e 100644
--- a/fs/lockd/svcshare.c
+++ b/fs/lockd/svcshare.c
@@ -85,24 +85,20 @@ nlmsvc_unshare_file(struct nlm_host *host, struct nlm_file *file,
 }
 
 /*
- * Traverse all shares for a given file (and host).
- * NLM_ACT_CHECK is handled by nlmsvc_inspect_file.
+ * Traverse all shares for a given file, and delete
+ * those owned by the given (type of) host
  */
-void
-nlmsvc_traverse_shares(struct nlm_host *host, struct nlm_file *file, int action)
+void nlmsvc_traverse_shares(struct nlm_host *host, struct nlm_file *file,
+                nlm_host_match_fn_t match)
 {
         struct nlm_share        *share, **shpp;
 
         shpp = &file->f_shares;
         while ((share = *shpp) !=  NULL) {
-                if (action == NLM_ACT_MARK)
-                        share->s_host->h_inuse = 1;
-                else if (action == NLM_ACT_UNLOCK) {
-                        if (host == NULL || host == share->s_host) {
-                                *shpp = share->s_next;
-                                kfree(share);
-                                continue;
-                        }
+                if (match(share->s_host, host)) {
+                        *shpp = share->s_next;
+                        kfree(share);
+                        continue;
                 }
                 shpp = &share->s_next;
         }
diff --git a/fs/lockd/svcsubs.c b/fs/lockd/svcsubs.c
index 91731353dfa4..bb13a48210f5 100644
--- a/fs/lockd/svcsubs.c
+++ b/fs/lockd/svcsubs.c
@@ -165,7 +165,8 @@ nlm_delete_file(struct nlm_file *file)
  * action.
  */
 static int
-nlm_traverse_locks(struct nlm_host *host, struct nlm_file *file, int action)
+nlm_traverse_locks(struct nlm_host *host, struct nlm_file *file,
+                        nlm_host_match_fn_t match)
 {
         struct inode     *inode = nlmsvc_file_inode(file);
         struct file_lock *fl;
@@ -179,17 +180,11 @@ again:
 
                 /* update current lock count */
                 file->f_locks++;
+
                 lockhost = (struct nlm_host *) fl->fl_owner;
-                if (action == NLM_ACT_MARK)
-                        lockhost->h_inuse = 1;
-                else if (action == NLM_ACT_CHECK)
-                        return 1;
-                else if (action == NLM_ACT_UNLOCK) {
+                if (match(lockhost, host)) {
                         struct file_lock lock = *fl;
 
-                        if (host && lockhost != host)
-                                continue;
-
                         lock.fl_type  = F_UNLCK;
                         lock.fl_start = 0;
                         lock.fl_end   = OFFSET_MAX;
@@ -206,27 +201,42 @@ again:
 }
 
 /*
- * Operate on a single file
+ * Inspect a single file
+ */
+static inline int
+nlm_inspect_file(struct nlm_host *host, struct nlm_file *file, nlm_host_match_fn_t match)
+{
+        nlmsvc_traverse_blocks(host, file, match);
+        nlmsvc_traverse_shares(host, file, match);
+        return nlm_traverse_locks(host, file, match);
+}
+
+/*
+ * Quick check whether there are still any locks, blocks or
+ * shares on a given file.
  */
 static inline int
-nlm_inspect_file(struct nlm_host *host, struct nlm_file *file, int action)
+nlm_file_inuse(struct nlm_file *file)
 {
-        if (action == NLM_ACT_CHECK) {
-                /* Fast path for mark and sweep garbage collection */
-                if (file->f_count || list_empty(&file->f_blocks) || file->f_shares)
+        struct inode     *inode = nlmsvc_file_inode(file);
+        struct file_lock *fl;
+
+        if (file->f_count || !list_empty(&file->f_blocks) || file->f_shares)
+                return 1;
+
+        for (fl = inode->i_flock; fl; fl = fl->fl_next) {
+                if (fl->fl_lmops == &nlmsvc_lock_operations)
                         return 1;
-        } else {
-                nlmsvc_traverse_blocks(host, file, action);
-                nlmsvc_traverse_shares(host, file, action);
         }
-        return nlm_traverse_locks(host, file, action);
+        file->f_locks = 0;
+        return 0;
 }
 
 /*
  * Loop over all files in the file table.
  */
 static int
-nlm_traverse_files(struct nlm_host *host, int action)
+nlm_traverse_files(struct nlm_host *host, nlm_host_match_fn_t match)
 {
         struct hlist_node *pos, *next;
         struct nlm_file *file;
@@ -240,7 +250,7 @@ nlm_traverse_files(struct nlm_host *host, int action)
 
                         /* Traverse locks, blocks and shares of this file
                          * and update file->f_locks count */
-                        if (nlm_inspect_file(host, file, action))
+                        if (nlm_inspect_file(host, file, match))
                                 ret = 1;
 
                         mutex_lock(&nlm_file_mutex);
@@ -277,23 +287,54 @@ nlm_release_file(struct nlm_file *file)
         mutex_lock(&nlm_file_mutex);
 
         /* If there are no more locks etc, delete the file */
-        if(--file->f_count == 0) {
-                if(!nlm_inspect_file(NULL, file, NLM_ACT_CHECK))
-                        nlm_delete_file(file);
-        }
+        if (--file->f_count == 0 && !nlm_file_inuse(file))
+                nlm_delete_file(file);
 
         mutex_unlock(&nlm_file_mutex);
 }
 
 /*
+ * Helpers function for resource traversal
+ *
+ * nlmsvc_mark_host:
+ *      used by the garbage collector; simply sets h_inuse.
+ *      Always returns 0.
+ *
+ * nlmsvc_same_host:
+ *      returns 1 iff the two hosts match. Used to release
+ *      all resources bound to a specific host.
+ *
+ * nlmsvc_is_client:
+ *      returns 1 iff the host is a client.
+ *      Used by nlmsvc_invalidate_all
+ */
+static int
+nlmsvc_mark_host(struct nlm_host *host, struct nlm_host *dummy)
+{
+        host->h_inuse = 1;
+        return 0;
+}
+
+static int
+nlmsvc_same_host(struct nlm_host *host, struct nlm_host *other)
+{
+        return host == other;
+}
+
+static int
+nlmsvc_is_client(struct nlm_host *host, struct nlm_host *dummy)
+{
+        return host->h_server;
+}
+
+/*
  * Mark all hosts that still hold resources
  */
 void
 nlmsvc_mark_resources(void)
 {
         dprintk("lockd: nlmsvc_mark_resources\n");
-
-        nlm_traverse_files(NULL, NLM_ACT_MARK);
+        nlm_traverse_files(NULL, nlmsvc_mark_host);
 }
 
 /*
@@ -304,7 +345,7 @@ nlmsvc_free_host_resources(struct nlm_host *host)
 {
         dprintk("lockd: nlmsvc_free_host_resources\n");
 
-        if (nlm_traverse_files(host, NLM_ACT_UNLOCK)) {
+        if (nlm_traverse_files(host, nlmsvc_same_host)) {
                 printk(KERN_WARNING
                         "lockd: couldn't remove all locks held by %s\n",
                         host->h_name);
@@ -319,8 +360,16 @@ void
 nlmsvc_invalidate_all(void)
 {
         struct nlm_host *host;
+
+        /* Release all locks held by NFS clients.
+         * Previously, the code would call
+         * nlmsvc_free_host_resources for each client in
+         * turn, which is about as inefficient as it gets.
+         * Now we just do it once in nlm_traverse_files.
+         */
+        nlm_traverse_files(NULL, nlmsvc_is_client);
+
         while ((host = nlm_find_client()) != NULL) {
-                nlmsvc_free_host_resources(host);
                 host->h_expires = 0;
                 host->h_killed = 1;
                 nlm_release_host(host);