1 files changed, 356 insertions, 19 deletions

diff --git a/fs/ocfs2/dcache.c b/fs/ocfs2/dcache.c
index aea457718946..09efe240e652 100644
--- a/fs/ocfs2/dcache.c
+++ b/fs/ocfs2/dcache.c
@@ -35,15 +35,17 @@
 
 #include "alloc.h"
 #include "dcache.h"
+#include "dlmglue.h"
 #include "file.h"
 #include "inode.h"
 
+
 static int ocfs2_dentry_revalidate(struct dentry *dentry,
                                    struct nameidata *nd)
 {
         struct inode *inode = dentry->d_inode;
         int ret = 0;    /* if all else fails, just return false */
-        struct ocfs2_super *osb;
+        struct ocfs2_super *osb = OCFS2_SB(dentry->d_sb);
 
         mlog_entry("(0x%p, '%.*s')\n", dentry,
                    dentry->d_name.len, dentry->d_name.name);
@@ -55,28 +57,31 @@ static int ocfs2_dentry_revalidate(struct dentry *dentry,
                 goto bail;
         }
 
-        osb = OCFS2_SB(inode->i_sb);
-
         BUG_ON(!osb);
 
-        if (inode != osb->root_inode) {
-                spin_lock(&OCFS2_I(inode)->ip_lock);
-                /* did we or someone else delete this inode? */
-                if (OCFS2_I(inode)->ip_flags & OCFS2_INODE_DELETED) {
-                        spin_unlock(&OCFS2_I(inode)->ip_lock);
-                        mlog(0, "inode (%llu) deleted, returning false\n",
-                             (unsigned long long)OCFS2_I(inode)->ip_blkno);
-                        goto bail;
-                }
+        if (inode == osb->root_inode || is_bad_inode(inode))
+                goto bail;
+
+        spin_lock(&OCFS2_I(inode)->ip_lock);
+        /* did we or someone else delete this inode? */
+        if (OCFS2_I(inode)->ip_flags & OCFS2_INODE_DELETED) {
                 spin_unlock(&OCFS2_I(inode)->ip_lock);
+                mlog(0, "inode (%llu) deleted, returning false\n",
+                     (unsigned long long)OCFS2_I(inode)->ip_blkno);
+                goto bail;
+        }
+        spin_unlock(&OCFS2_I(inode)->ip_lock);
 
-                if (!inode->i_nlink) {
-                        mlog(0, "Inode %llu orphaned, returning false "
-                             "dir = %d\n",
-                             (unsigned long long)OCFS2_I(inode)->ip_blkno,
-                             S_ISDIR(inode->i_mode));
-                        goto bail;
-                }
+        /*
+         * We don't need a cluster lock to test this because once an
+         * inode nlink hits zero, it never goes back.
+         */
+        if (inode->i_nlink == 0) {
+                mlog(0, "Inode %llu orphaned, returning false "
+                     "dir = %d\n",
+                     (unsigned long long)OCFS2_I(inode)->ip_blkno,
+                     S_ISDIR(inode->i_mode));
+                goto bail;
         }
 
         ret = 1;
@@ -87,8 +92,340 @@ bail:
         return ret;
 }
 
+static int ocfs2_match_dentry(struct dentry *dentry,
+                              u64 parent_blkno,
+                              int skip_unhashed)
+{
+        struct inode *parent;
+
+        /*
+         * ocfs2_lookup() does a d_splice_alias() _before_ attaching
+         * to the lock data, so we skip those here, otherwise
+         * ocfs2_dentry_attach_lock() will get its original dentry
+         * back.
+         */
+        if (!dentry->d_fsdata)
+                return 0;
+
+        if (!dentry->d_parent)
+                return 0;
+
+        if (skip_unhashed && d_unhashed(dentry))
+                return 0;
+
+        parent = dentry->d_parent->d_inode;
+        /* Negative parent dentry? */
+        if (!parent)
+                return 0;
+
+        /* Name is in a different directory. */
+        if (OCFS2_I(parent)->ip_blkno != parent_blkno)
+                return 0;
+
+        return 1;
+}
+
+/*
+ * Walk the inode alias list, and find a dentry which has a given
+ * parent. ocfs2_dentry_attach_lock() wants to find _any_ alias as it
+ * is looking for a dentry_lock reference. The vote thread is looking
+ * to unhash aliases, so we allow it to skip any that already have
+ * that property.
+ */
+struct dentry *ocfs2_find_local_alias(struct inode *inode,
+                                      u64 parent_blkno,
+                                      int skip_unhashed)
+{
+        struct list_head *p;
+        struct dentry *dentry = NULL;
+
+        spin_lock(&dcache_lock);
+
+        list_for_each(p, &inode->i_dentry) {
+                dentry = list_entry(p, struct dentry, d_alias);
+
+                if (ocfs2_match_dentry(dentry, parent_blkno, skip_unhashed)) {
+                        mlog(0, "dentry found: %.*s\n",
+                             dentry->d_name.len, dentry->d_name.name);
+
+                        dget_locked(dentry);
+                        break;
+                }
+
+                dentry = NULL;
+        }
+
+        spin_unlock(&dcache_lock);
+
+        return dentry;
+}
+
 DEFINE_SPINLOCK(dentry_attach_lock);
 
+/*
+ * Attach this dentry to a cluster lock.
+ *
+ * Dentry locks cover all links in a given directory to a particular
+ * inode. We do this so that ocfs2 can build a lock name which all
+ * nodes in the cluster can agree on at all times. Shoving full names
+ * in the cluster lock won't work due to size restrictions. Covering
+ * links inside of a directory is a good compromise because it still
+ * allows us to use the parent directory lock to synchronize
+ * operations.
+ *
+ * Call this function with the parent dir semaphore and the parent dir
+ * cluster lock held.
+ *
+ * The dir semaphore will protect us from having to worry about
+ * concurrent processes on our node trying to attach a lock at the
+ * same time.
+ *
+ * The dir cluster lock (held at either PR or EX mode) protects us
+ * from unlink and rename on other nodes.
+ *
+ * The 'create' flag tells us whether we're doing this as a result of
+ * a file creation.
+ *
+ * A dput() can happen asynchronously due to pruning, so we cover
+ * attaching and detaching the dentry lock with a
+ * dentry_attach_lock.
+ *
+ * A node which has done lookup on a name retains a protected read
+ * lock until final dput. If the user requests and unlink or rename,
+ * the protected read is upgraded to an exclusive lock. Other nodes
+ * who have seen the dentry will then be informed that they need to
+ * downgrade their lock, which will involve d_delete on the
+ * dentry. This happens in ocfs2_dentry_convert_worker().
+ */
+int ocfs2_dentry_attach_lock(struct dentry *dentry,
+                             struct inode *inode,
+                             u64 parent_blkno,
+                             int create)
+{
+        int ret;
+        struct dentry *alias;
+        struct ocfs2_dentry_lock *dl = dentry->d_fsdata;
+
+        mlog(0, "Attach \"%.*s\", parent %llu, create %d, fsdata: %p\n",
+             dentry->d_name.len, dentry->d_name.name,
+             (unsigned long long)parent_blkno, create, dl);
+
+        /*
+         * Negative dentry. We ignore these for now.
+         *
+         * XXX: Could we can improve ocfs2_dentry_revalidate() by
+         * tracking these?
+         */
+        if (!inode)
+                return 0;
+
+        if (dl) {
+                mlog_bug_on_msg(dl->dl_parent_blkno != parent_blkno,
+                                " \"%.*s\": old parent: %llu, new: %llu\n",
+                                dentry->d_name.len, dentry->d_name.name,
+                                (unsigned long long)parent_blkno,
+                                (unsigned long long)dl->dl_parent_blkno);
+                return 0;
+        }
+
+        alias = ocfs2_find_local_alias(inode, parent_blkno, 0);
+        if (alias) {
+                /*
+                 * Great, an alias exists, which means we must have a
+                 * dentry lock already. We can just grab the lock off
+                 * the alias and add it to the list.
+                 *
+                 * We're depending here on the fact that this dentry
+                 * was found and exists in the dcache and so must have
+                 * a reference to the dentry_lock because we can't
+                 * race creates. Final dput() cannot happen on it
+                 * since we have it pinned, so our reference is safe.
+                 */
+                dl = alias->d_fsdata;
+                mlog_bug_on_msg(!dl, "parent %llu, ino %llu, create %d\n",
+                                (unsigned long long)parent_blkno,
+                                (unsigned long long)OCFS2_I(inode)->ip_blkno,
+                                create);
+
+                mlog_bug_on_msg(dl->dl_parent_blkno != parent_blkno,
+                                " \"%.*s\": old parent: %llu, new: %llu\n",
+                                dentry->d_name.len, dentry->d_name.name,
+                                (unsigned long long)parent_blkno,
+                                (unsigned long long)dl->dl_parent_blkno);
+
+                mlog(0, "Found: %s\n", dl->dl_lockres.l_name);
+
+                goto out_attach;
+        }
+
+        /*
+         * There are no other aliases
+         */
+        dl = kmalloc(sizeof(*dl), GFP_NOFS);
+        if (!dl) {
+                ret = -ENOMEM;
+                mlog_errno(ret);
+                return ret;
+        }
+
+        dl->dl_count = 0;
+        /*
+         * Does this have to happen below, for all attaches, in case
+         * the struct inode gets blown away by votes?
+         */
+        dl->dl_inode = igrab(inode);
+        dl->dl_parent_blkno = parent_blkno;
+        ocfs2_dentry_lock_res_init(dl, parent_blkno, inode);
+
+out_attach:
+        spin_lock(&dentry_attach_lock);
+        dentry->d_fsdata = dl;
+        dl->dl_count++;
+        spin_unlock(&dentry_attach_lock);
+
+        /*
+         * Creation of a new file means that nobody can possibly have
+         * this name in the system, which means that acquiry of those
+         * locks can easily be optimized.
+         */
+        if (create) {
+                ret = ocfs2_create_new_lock(OCFS2_SB(inode->i_sb),
+                                            &dl->dl_lockres, 0);
+                if (ret)
+                        mlog_errno(ret);
+                goto out;
+        }
+
+        /*
+         * This actually gets us our PRMODE level lock. From now on,
+         * we'll have a notification if one of these names is
+         * destroyed on another node.
+         */
+        ret = ocfs2_dentry_lock(dentry, 0);
+        if (ret) {
+                mlog_errno(ret);
+                goto out;
+        }
+        ocfs2_dentry_unlock(dentry, 0);
+
+out:
+        dput(alias);
+
+        return ret;
+}
+
+/*
+ * ocfs2_dentry_iput() and friends.
+ *
+ * At this point, our particular dentry is detached from the inodes
+ * alias list, so there's no way that the locking code can find it.
+ *
+ * The interesting stuff happens when we determine that our lock needs
+ * to go away because this is the last subdir alias in the
+ * system. This function needs to handle a couple things:
+ *
+ * 1) Synchronizing lock shutdown with the downconvert threads. This
+ *    is already handled for us via the lockres release drop function
+ *    called in ocfs2_release_dentry_lock()
+ *
+ * 2) A race may occur when we're doing our lock shutdown and
+ *    another process wants to create a new dentry lock. Right now we
+ *    let them race, which means that for a very short while, this
+ *    node might have two locks on a lock resource. This should be a
+ *    problem though because one of them is in the process of being
+ *    thrown out.
+ */
+static void ocfs2_drop_dentry_lock(struct ocfs2_super *osb,
+                                   struct ocfs2_dentry_lock *dl)
+{
+        ocfs2_simple_drop_lockres(osb, &dl->dl_lockres);
+        ocfs2_lock_res_free(&dl->dl_lockres);
+        iput(dl->dl_inode);
+        kfree(dl);
+}
+
+void ocfs2_dentry_lock_put(struct ocfs2_super *osb,
+                           struct ocfs2_dentry_lock *dl)
+{
+        int unlock = 0;
+
+        BUG_ON(dl->dl_count == 0);
+
+        spin_lock(&dentry_attach_lock);
+        dl->dl_count--;
+        unlock = !dl->dl_count;
+        spin_unlock(&dentry_attach_lock);
+
+        if (unlock)
+                ocfs2_drop_dentry_lock(osb, dl);
+}
+
+static void ocfs2_dentry_iput(struct dentry *dentry, struct inode *inode)
+{
+        struct ocfs2_dentry_lock *dl = dentry->d_fsdata;
+
+        mlog_bug_on_msg(!dl && !(dentry->d_flags & DCACHE_DISCONNECTED),
+                        "dentry: %.*s\n", dentry->d_name.len,
+                        dentry->d_name.name);
+
+        if (!dl)
+                goto out;
+
+        mlog_bug_on_msg(dl->dl_count == 0, "dentry: %.*s, count: %u\n",
+                        dentry->d_name.len, dentry->d_name.name,
+                        dl->dl_count);
+
+        ocfs2_dentry_lock_put(OCFS2_SB(dentry->d_sb), dl);
+
+out:
+        iput(inode);
+}
+
+/*
+ * d_move(), but keep the locks in sync.
+ *
+ * When we are done, "dentry" will have the parent dir and name of
+ * "target", which will be thrown away.
+ *
+ * We manually update the lock of "dentry" if need be.
+ *
+ * "target" doesn't have it's dentry lock touched - we allow the later
+ * dput() to handle this for us.
+ *
+ * This is called during ocfs2_rename(), while holding parent
+ * directory locks. The dentries have already been deleted on other
+ * nodes via ocfs2_remote_dentry_delete().
+ *
+ * Normally, the VFS handles the d_move() for the file sytem, after
+ * the ->rename() callback. OCFS2 wants to handle this internally, so
+ * the new lock can be created atomically with respect to the cluster.
+ */
+void ocfs2_dentry_move(struct dentry *dentry, struct dentry *target,
+                       struct inode *old_dir, struct inode *new_dir)
+{
+        int ret;
+        struct ocfs2_super *osb = OCFS2_SB(old_dir->i_sb);
+        struct inode *inode = dentry->d_inode;
+
+        /*
+         * Move within the same directory, so the actual lock info won't
+         * change.
+         *
+         * XXX: Is there any advantage to dropping the lock here?
+         */
+        if (old_dir == new_dir)
+                return;
+
+        ocfs2_dentry_lock_put(osb, dentry->d_fsdata);
+
+        dentry->d_fsdata = NULL;
+        ret = ocfs2_dentry_attach_lock(dentry, inode,
+                                       OCFS2_I(new_dir)->ip_blkno, 0);
+        if (ret)
+                mlog_errno(ret);
+}
+
 struct dentry_operations ocfs2_dentry_ops = {
         .d_revalidate           = ocfs2_dentry_revalidate,
+        .d_iput                 = ocfs2_dentry_iput,
 };