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@@ -35,15 +35,17 @@
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#include "alloc.h"
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#include "dcache.h"
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+#include "dlmglue.h"
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#include "file.h"
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#include "inode.h"
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+
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static int ocfs2_dentry_revalidate(struct dentry *dentry,
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struct nameidata *nd)
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{
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struct inode *inode = dentry->d_inode;
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int ret = 0; /* if all else fails, just return false */
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- struct ocfs2_super *osb;
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+ struct ocfs2_super *osb = OCFS2_SB(dentry->d_sb);
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mlog_entry("(0x%p, '%.*s')\n", dentry,
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dentry->d_name.len, dentry->d_name.name);
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@@ -55,28 +57,31 @@ static int ocfs2_dentry_revalidate(struct dentry *dentry,
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goto bail;
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}
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- osb = OCFS2_SB(inode->i_sb);
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-
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BUG_ON(!osb);
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- if (inode != osb->root_inode) {
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- spin_lock(&OCFS2_I(inode)->ip_lock);
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- /* did we or someone else delete this inode? */
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- if (OCFS2_I(inode)->ip_flags & OCFS2_INODE_DELETED) {
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- spin_unlock(&OCFS2_I(inode)->ip_lock);
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- mlog(0, "inode (%llu) deleted, returning false\n",
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- (unsigned long long)OCFS2_I(inode)->ip_blkno);
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- goto bail;
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- }
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+ if (inode == osb->root_inode || is_bad_inode(inode))
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+ goto bail;
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+
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+ spin_lock(&OCFS2_I(inode)->ip_lock);
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+ /* did we or someone else delete this inode? */
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+ if (OCFS2_I(inode)->ip_flags & OCFS2_INODE_DELETED) {
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spin_unlock(&OCFS2_I(inode)->ip_lock);
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+ mlog(0, "inode (%llu) deleted, returning false\n",
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+ (unsigned long long)OCFS2_I(inode)->ip_blkno);
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+ goto bail;
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+ }
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+ spin_unlock(&OCFS2_I(inode)->ip_lock);
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- if (!inode->i_nlink) {
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- mlog(0, "Inode %llu orphaned, returning false "
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- "dir = %d\n",
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- (unsigned long long)OCFS2_I(inode)->ip_blkno,
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- S_ISDIR(inode->i_mode));
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- goto bail;
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- }
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+ /*
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+ * We don't need a cluster lock to test this because once an
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+ * inode nlink hits zero, it never goes back.
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+ */
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+ if (inode->i_nlink == 0) {
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+ mlog(0, "Inode %llu orphaned, returning false "
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+ "dir = %d\n",
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+ (unsigned long long)OCFS2_I(inode)->ip_blkno,
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+ S_ISDIR(inode->i_mode));
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+ goto bail;
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}
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ret = 1;
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@@ -87,6 +92,322 @@ bail:
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return ret;
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}
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+static int ocfs2_match_dentry(struct dentry *dentry,
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+ u64 parent_blkno,
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+ int skip_unhashed)
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+{
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+ struct inode *parent;
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+
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+ /*
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+ * ocfs2_lookup() does a d_splice_alias() _before_ attaching
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+ * to the lock data, so we skip those here, otherwise
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+ * ocfs2_dentry_attach_lock() will get its original dentry
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+ * back.
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+ */
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+ if (!dentry->d_fsdata)
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+ return 0;
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+
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+ if (!dentry->d_parent)
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+ return 0;
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+
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+ if (skip_unhashed && d_unhashed(dentry))
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+ return 0;
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+
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+ parent = dentry->d_parent->d_inode;
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+ /* Negative parent dentry? */
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+ if (!parent)
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+ return 0;
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+
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+ /* Name is in a different directory. */
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+ if (OCFS2_I(parent)->ip_blkno != parent_blkno)
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+ return 0;
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+
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+ return 1;
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+}
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+
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+/*
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+ * Walk the inode alias list, and find a dentry which has a given
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+ * parent. ocfs2_dentry_attach_lock() wants to find _any_ alias as it
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+ * is looking for a dentry_lock reference. The vote thread is looking
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+ * to unhash aliases, so we allow it to skip any that already have
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+ * that property.
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+ */
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+struct dentry *ocfs2_find_local_alias(struct inode *inode,
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+ u64 parent_blkno,
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+ int skip_unhashed)
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+{
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+ struct list_head *p;
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+ struct dentry *dentry = NULL;
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+
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+ spin_lock(&dcache_lock);
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+
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+ list_for_each(p, &inode->i_dentry) {
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+ dentry = list_entry(p, struct dentry, d_alias);
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+
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+ if (ocfs2_match_dentry(dentry, parent_blkno, skip_unhashed)) {
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+ mlog(0, "dentry found: %.*s\n",
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+ dentry->d_name.len, dentry->d_name.name);
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+
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+ dget_locked(dentry);
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+ break;
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+ }
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+
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+ dentry = NULL;
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+ }
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+
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+ spin_unlock(&dcache_lock);
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+
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+ return dentry;
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+}
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+
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+DEFINE_SPINLOCK(dentry_attach_lock);
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+
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+/*
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+ * Attach this dentry to a cluster lock.
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+ *
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+ * Dentry locks cover all links in a given directory to a particular
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+ * inode. We do this so that ocfs2 can build a lock name which all
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+ * nodes in the cluster can agree on at all times. Shoving full names
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+ * in the cluster lock won't work due to size restrictions. Covering
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+ * links inside of a directory is a good compromise because it still
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+ * allows us to use the parent directory lock to synchronize
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+ * operations.
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+ *
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+ * Call this function with the parent dir semaphore and the parent dir
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+ * cluster lock held.
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+ *
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+ * The dir semaphore will protect us from having to worry about
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+ * concurrent processes on our node trying to attach a lock at the
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+ * same time.
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+ *
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+ * The dir cluster lock (held at either PR or EX mode) protects us
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+ * from unlink and rename on other nodes.
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+ *
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+ * A dput() can happen asynchronously due to pruning, so we cover
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+ * attaching and detaching the dentry lock with a
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+ * dentry_attach_lock.
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+ *
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+ * A node which has done lookup on a name retains a protected read
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+ * lock until final dput. If the user requests and unlink or rename,
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+ * the protected read is upgraded to an exclusive lock. Other nodes
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+ * who have seen the dentry will then be informed that they need to
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+ * downgrade their lock, which will involve d_delete on the
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+ * dentry. This happens in ocfs2_dentry_convert_worker().
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+ */
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+int ocfs2_dentry_attach_lock(struct dentry *dentry,
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+ struct inode *inode,
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+ u64 parent_blkno)
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+{
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+ int ret;
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+ struct dentry *alias;
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+ struct ocfs2_dentry_lock *dl = dentry->d_fsdata;
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+
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+ mlog(0, "Attach \"%.*s\", parent %llu, fsdata: %p\n",
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+ dentry->d_name.len, dentry->d_name.name,
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+ (unsigned long long)parent_blkno, dl);
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+
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+ /*
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+ * Negative dentry. We ignore these for now.
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+ *
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+ * XXX: Could we can improve ocfs2_dentry_revalidate() by
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+ * tracking these?
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+ */
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+ if (!inode)
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+ return 0;
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+
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+ if (dl) {
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+ mlog_bug_on_msg(dl->dl_parent_blkno != parent_blkno,
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+ " \"%.*s\": old parent: %llu, new: %llu\n",
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+ dentry->d_name.len, dentry->d_name.name,
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+ (unsigned long long)parent_blkno,
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+ (unsigned long long)dl->dl_parent_blkno);
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+ return 0;
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+ }
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+
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+ alias = ocfs2_find_local_alias(inode, parent_blkno, 0);
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+ if (alias) {
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+ /*
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+ * Great, an alias exists, which means we must have a
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+ * dentry lock already. We can just grab the lock off
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+ * the alias and add it to the list.
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+ *
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+ * We're depending here on the fact that this dentry
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+ * was found and exists in the dcache and so must have
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+ * a reference to the dentry_lock because we can't
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+ * race creates. Final dput() cannot happen on it
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+ * since we have it pinned, so our reference is safe.
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+ */
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+ dl = alias->d_fsdata;
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+ mlog_bug_on_msg(!dl, "parent %llu, ino %llu\n",
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+ (unsigned long long)parent_blkno,
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+ (unsigned long long)OCFS2_I(inode)->ip_blkno);
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+
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+ mlog_bug_on_msg(dl->dl_parent_blkno != parent_blkno,
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+ " \"%.*s\": old parent: %llu, new: %llu\n",
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+ dentry->d_name.len, dentry->d_name.name,
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+ (unsigned long long)parent_blkno,
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+ (unsigned long long)dl->dl_parent_blkno);
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+
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+ mlog(0, "Found: %s\n", dl->dl_lockres.l_name);
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+
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+ goto out_attach;
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+ }
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+
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+ /*
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+ * There are no other aliases
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+ */
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+ dl = kmalloc(sizeof(*dl), GFP_NOFS);
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+ if (!dl) {
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+ ret = -ENOMEM;
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+ mlog_errno(ret);
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+ return ret;
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+ }
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+
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+ dl->dl_count = 0;
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+ /*
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+ * Does this have to happen below, for all attaches, in case
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+ * the struct inode gets blown away by votes?
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+ */
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+ dl->dl_inode = igrab(inode);
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+ dl->dl_parent_blkno = parent_blkno;
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+ ocfs2_dentry_lock_res_init(dl, parent_blkno, inode);
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+
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+out_attach:
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+ spin_lock(&dentry_attach_lock);
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+ dentry->d_fsdata = dl;
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+ dl->dl_count++;
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+ spin_unlock(&dentry_attach_lock);
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+
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+ /*
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+ * This actually gets us our PRMODE level lock. From now on,
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+ * we'll have a notification if one of these names is
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+ * destroyed on another node.
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+ */
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+ ret = ocfs2_dentry_lock(dentry, 0);
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+ if (!ret)
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+ ocfs2_dentry_unlock(dentry, 0);
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+ else
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+ mlog_errno(ret);
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+
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+ dput(alias);
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+
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+ return ret;
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+}
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+
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+/*
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+ * ocfs2_dentry_iput() and friends.
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+ *
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+ * At this point, our particular dentry is detached from the inodes
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+ * alias list, so there's no way that the locking code can find it.
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+ *
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+ * The interesting stuff happens when we determine that our lock needs
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+ * to go away because this is the last subdir alias in the
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+ * system. This function needs to handle a couple things:
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+ *
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+ * 1) Synchronizing lock shutdown with the downconvert threads. This
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+ * is already handled for us via the lockres release drop function
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+ * called in ocfs2_release_dentry_lock()
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+ *
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+ * 2) A race may occur when we're doing our lock shutdown and
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+ * another process wants to create a new dentry lock. Right now we
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+ * let them race, which means that for a very short while, this
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+ * node might have two locks on a lock resource. This should be a
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+ * problem though because one of them is in the process of being
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+ * thrown out.
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+ */
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+static void ocfs2_drop_dentry_lock(struct ocfs2_super *osb,
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+ struct ocfs2_dentry_lock *dl)
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+{
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+ ocfs2_simple_drop_lockres(osb, &dl->dl_lockres);
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+ ocfs2_lock_res_free(&dl->dl_lockres);
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+ iput(dl->dl_inode);
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+ kfree(dl);
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+}
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+
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+void ocfs2_dentry_lock_put(struct ocfs2_super *osb,
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+ struct ocfs2_dentry_lock *dl)
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+{
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+ int unlock = 0;
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+
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+ BUG_ON(dl->dl_count == 0);
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+
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+ spin_lock(&dentry_attach_lock);
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+ dl->dl_count--;
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+ unlock = !dl->dl_count;
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+ spin_unlock(&dentry_attach_lock);
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+
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+ if (unlock)
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+ ocfs2_drop_dentry_lock(osb, dl);
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+}
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+
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+static void ocfs2_dentry_iput(struct dentry *dentry, struct inode *inode)
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+{
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+ struct ocfs2_dentry_lock *dl = dentry->d_fsdata;
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+
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+ mlog_bug_on_msg(!dl && !(dentry->d_flags & DCACHE_DISCONNECTED),
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+ "dentry: %.*s\n", dentry->d_name.len,
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+ dentry->d_name.name);
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+
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+ if (!dl)
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+ goto out;
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+
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+ mlog_bug_on_msg(dl->dl_count == 0, "dentry: %.*s, count: %u\n",
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+ dentry->d_name.len, dentry->d_name.name,
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+ dl->dl_count);
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+
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+ ocfs2_dentry_lock_put(OCFS2_SB(dentry->d_sb), dl);
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+
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+out:
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+ iput(inode);
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+}
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+
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+/*
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+ * d_move(), but keep the locks in sync.
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+ *
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+ * When we are done, "dentry" will have the parent dir and name of
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+ * "target", which will be thrown away.
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+ *
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+ * We manually update the lock of "dentry" if need be.
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+ *
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+ * "target" doesn't have it's dentry lock touched - we allow the later
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+ * dput() to handle this for us.
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+ *
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+ * This is called during ocfs2_rename(), while holding parent
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+ * directory locks. The dentries have already been deleted on other
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+ * nodes via ocfs2_remote_dentry_delete().
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+ *
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+ * Normally, the VFS handles the d_move() for the file sytem, after
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+ * the ->rename() callback. OCFS2 wants to handle this internally, so
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+ * the new lock can be created atomically with respect to the cluster.
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+ */
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+void ocfs2_dentry_move(struct dentry *dentry, struct dentry *target,
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+ struct inode *old_dir, struct inode *new_dir)
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+{
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+ int ret;
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+ struct ocfs2_super *osb = OCFS2_SB(old_dir->i_sb);
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+ struct inode *inode = dentry->d_inode;
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+
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+ /*
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+ * Move within the same directory, so the actual lock info won't
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+ * change.
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+ *
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+ * XXX: Is there any advantage to dropping the lock here?
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+ */
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+ if (old_dir == new_dir)
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+ goto out_move;
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+
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+ ocfs2_dentry_lock_put(osb, dentry->d_fsdata);
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+
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+ dentry->d_fsdata = NULL;
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+ ret = ocfs2_dentry_attach_lock(dentry, inode, OCFS2_I(new_dir)->ip_blkno);
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+ if (ret)
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+ mlog_errno(ret);
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+
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+out_move:
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+ d_move(dentry, target);
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+}
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+
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struct dentry_operations ocfs2_dentry_ops = {
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.d_revalidate = ocfs2_dentry_revalidate,
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+ .d_iput = ocfs2_dentry_iput,
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};
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