Initial import of modified Linux 2.6.28 tree

Original upstream URL:
git://git.kernel.org/pub/scm/linux/kernel/git/stable/linux-stable.git | branch linux-2.6.28.y

1 files changed, 520 insertions, 0 deletions

diff --git a/fs/unionfs/rename.c b/fs/unionfs/rename.c
new file mode 100644
index 0000000..ed13260
--- /dev/null
+++ b/fs/unionfs/rename.c
@@ -0,0 +1,520 @@
+/*
+ * Copyright (c) 2003-2009 Erez Zadok
+ * Copyright (c) 2003-2006 Charles P. Wright
+ * Copyright (c) 2005-2007 Josef 'Jeff' Sipek
+ * Copyright (c) 2005-2006 Junjiro Okajima
+ * Copyright (c) 2005      Arun M. Krishnakumar
+ * Copyright (c) 2004-2006 David P. Quigley
+ * Copyright (c) 2003-2004 Mohammad Nayyer Zubair
+ * Copyright (c) 2003      Puja Gupta
+ * Copyright (c) 2003      Harikesavan Krishnan
+ * Copyright (c) 2003-2009 Stony Brook University
+ * Copyright (c) 2003-2009 The Research Foundation of SUNY
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License version 2 as
+ * published by the Free Software Foundation.
+ */
+
+#include "union.h"
+
+/*
+ * This is a helper function for rename, used when rename ends up with hosed
+ * over dentries and we need to revert.
+ */
+static int unionfs_refresh_lower_dentry(struct dentry *dentry,
+					struct dentry *parent, int bindex)
+{
+	struct dentry *lower_dentry;
+	struct dentry *lower_parent;
+	int err = 0;
+
+	verify_locked(dentry);
+
+	lower_parent = unionfs_lower_dentry_idx(parent, bindex);
+
+	BUG_ON(!S_ISDIR(lower_parent->d_inode->i_mode));
+
+	lower_dentry = lookup_one_len(dentry->d_name.name, lower_parent,
+				      dentry->d_name.len);
+	if (IS_ERR(lower_dentry)) {
+		err = PTR_ERR(lower_dentry);
+		goto out;
+	}
+
+	dput(unionfs_lower_dentry_idx(dentry, bindex));
+	iput(unionfs_lower_inode_idx(dentry->d_inode, bindex));
+	unionfs_set_lower_inode_idx(dentry->d_inode, bindex, NULL);
+
+	if (!lower_dentry->d_inode) {
+		dput(lower_dentry);
+		unionfs_set_lower_dentry_idx(dentry, bindex, NULL);
+	} else {
+		unionfs_set_lower_dentry_idx(dentry, bindex, lower_dentry);
+		unionfs_set_lower_inode_idx(dentry->d_inode, bindex,
+					    igrab(lower_dentry->d_inode));
+	}
+
+out:
+	return err;
+}
+
+static int __unionfs_rename(struct inode *old_dir, struct dentry *old_dentry,
+			    struct dentry *old_parent,
+			    struct inode *new_dir, struct dentry *new_dentry,
+			    struct dentry *new_parent,
+			    int bindex)
+{
+	int err = 0;
+	struct dentry *lower_old_dentry;
+	struct dentry *lower_new_dentry;
+	struct dentry *lower_old_dir_dentry;
+	struct dentry *lower_new_dir_dentry;
+	struct dentry *trap;
+
+	lower_new_dentry = unionfs_lower_dentry_idx(new_dentry, bindex);
+	lower_old_dentry = unionfs_lower_dentry_idx(old_dentry, bindex);
+
+	if (!lower_new_dentry) {
+		lower_new_dentry =
+			create_parents(new_parent->d_inode,
+				       new_dentry, new_dentry->d_name.name,
+				       bindex);
+		if (IS_ERR(lower_new_dentry)) {
+			err = PTR_ERR(lower_new_dentry);
+			if (IS_COPYUP_ERR(err))
+				goto out;
+			printk(KERN_ERR "unionfs: error creating directory "
+			       "tree for rename, bindex=%d err=%d\n",
+			       bindex, err);
+			goto out;
+		}
+	}
+
+	/* check for and remove whiteout, if any */
+	err = check_unlink_whiteout(new_dentry, lower_new_dentry, bindex);
+	if (err > 0) /* ignore if whiteout found and successfully removed */
+		err = 0;
+	if (err)
+		goto out;
+
+	/* check of old_dentry branch is writable */
+	err = is_robranch_super(old_dentry->d_sb, bindex);
+	if (err)
+		goto out;
+
+	dget(lower_old_dentry);
+	dget(lower_new_dentry);
+	lower_old_dir_dentry = dget_parent(lower_old_dentry);
+	lower_new_dir_dentry = dget_parent(lower_new_dentry);
+
+	/* see Documentation/filesystems/unionfs/issues.txt */
+	lockdep_off();
+	trap = lock_rename(lower_old_dir_dentry, lower_new_dir_dentry);
+	/* source should not be ancenstor of target */
+	if (trap == lower_old_dentry) {
+		err = -EINVAL;
+		goto out_err_unlock;
+	}
+	/* target should not be ancenstor of source */
+	if (trap == lower_new_dentry) {
+		err = -ENOTEMPTY;
+		goto out_err_unlock;
+	}
+	err = vfs_rename(lower_old_dir_dentry->d_inode, lower_old_dentry,
+			 lower_new_dir_dentry->d_inode, lower_new_dentry);
+out_err_unlock:
+	if (!err) {
+		/* update parent dir times */
+		fsstack_copy_attr_times(old_dir, lower_old_dir_dentry->d_inode);
+		fsstack_copy_attr_times(new_dir, lower_new_dir_dentry->d_inode);
+	}
+	unlock_rename(lower_old_dir_dentry, lower_new_dir_dentry);
+	lockdep_on();
+
+	dput(lower_old_dir_dentry);
+	dput(lower_new_dir_dentry);
+	dput(lower_old_dentry);
+	dput(lower_new_dentry);
+
+out:
+	if (!err) {
+		/* Fixup the new_dentry. */
+		if (bindex < dbstart(new_dentry))
+			dbstart(new_dentry) = bindex;
+		else if (bindex > dbend(new_dentry))
+			dbend(new_dentry) = bindex;
+	}
+
+	return err;
+}
+
+/*
+ * Main rename code.  This is sufficiently complex, that it's documented in
+ * Documentation/filesystems/unionfs/rename.txt.  This routine calls
+ * __unionfs_rename() above to perform some of the work.
+ */
+static int do_unionfs_rename(struct inode *old_dir,
+			     struct dentry *old_dentry,
+			     struct dentry *old_parent,
+			     struct inode *new_dir,
+			     struct dentry *new_dentry,
+			     struct dentry *new_parent)
+{
+	int err = 0;
+	int bindex;
+	int old_bstart, old_bend;
+	int new_bstart, new_bend;
+	int do_copyup = -1;
+	int local_err = 0;
+	int eio = 0;
+	int revert = 0;
+
+	old_bstart = dbstart(old_dentry);
+	old_bend = dbend(old_dentry);
+
+	new_bstart = dbstart(new_dentry);
+	new_bend = dbend(new_dentry);
+
+	/* Rename source to destination. */
+	err = __unionfs_rename(old_dir, old_dentry, old_parent,
+			       new_dir, new_dentry, new_parent,
+			       old_bstart);
+	if (err) {
+		if (!IS_COPYUP_ERR(err))
+			goto out;
+		do_copyup = old_bstart - 1;
+	} else {
+		revert = 1;
+	}
+
+	/*
+	 * Unlink all instances of destination that exist to the left of
+	 * bstart of source. On error, revert back, goto out.
+	 */
+	for (bindex = old_bstart - 1; bindex >= new_bstart; bindex--) {
+		struct dentry *unlink_dentry;
+		struct dentry *unlink_dir_dentry;
+
+		BUG_ON(bindex < 0);
+		unlink_dentry = unionfs_lower_dentry_idx(new_dentry, bindex);
+		if (!unlink_dentry)
+			continue;
+
+		unlink_dir_dentry = lock_parent(unlink_dentry);
+		err = is_robranch_super(old_dir->i_sb, bindex);
+		if (!err)
+			err = vfs_unlink(unlink_dir_dentry->d_inode,
+					 unlink_dentry);
+
+		fsstack_copy_attr_times(new_parent->d_inode,
+					unlink_dir_dentry->d_inode);
+		/* propagate number of hard-links */
+		new_parent->d_inode->i_nlink =
+			unionfs_get_nlinks(new_parent->d_inode);
+
+		unlock_dir(unlink_dir_dentry);
+		if (!err) {
+			if (bindex != new_bstart) {
+				dput(unlink_dentry);
+				unionfs_set_lower_dentry_idx(new_dentry,
+							     bindex, NULL);
+			}
+		} else if (IS_COPYUP_ERR(err)) {
+			do_copyup = bindex - 1;
+		} else if (revert) {
+			goto revert;
+		}
+	}
+
+	if (do_copyup != -1) {
+		for (bindex = do_copyup; bindex >= 0; bindex--) {
+			/*
+			 * copyup the file into some left directory, so that
+			 * you can rename it
+			 */
+			err = copyup_dentry(old_parent->d_inode,
+					    old_dentry, old_bstart, bindex,
+					    old_dentry->d_name.name,
+					    old_dentry->d_name.len, NULL,
+					    i_size_read(old_dentry->d_inode));
+			/* if copyup failed, try next branch to the left */
+			if (err)
+				continue;
+			/*
+			 * create whiteout before calling __unionfs_rename
+			 * because the latter will change the old_dentry's
+			 * lower name and parent dir, resulting in the
+			 * whiteout getting created in the wrong dir.
+			 */
+			err = create_whiteout(old_dentry, bindex);
+			if (err) {
+				printk(KERN_ERR "unionfs: can't create a "
+				       "whiteout for %s in rename (err=%d)\n",
+				       old_dentry->d_name.name, err);
+				continue;
+			}
+			err = __unionfs_rename(old_dir, old_dentry, old_parent,
+					       new_dir, new_dentry, new_parent,
+					       bindex);
+			break;
+		}
+	}
+
+	/* make it opaque */
+	if (S_ISDIR(old_dentry->d_inode->i_mode)) {
+		err = make_dir_opaque(old_dentry, dbstart(old_dentry));
+		if (err)
+			goto revert;
+	}
+
+	/*
+	 * Create whiteout for source, only if:
+	 * (1) There is more than one underlying instance of source.
+	 * (We did a copy_up is taken care of above).
+	 */
+	if ((old_bstart != old_bend) && (do_copyup == -1)) {
+		err = create_whiteout(old_dentry, old_bstart);
+		if (err) {
+			/* can't fix anything now, so we exit with -EIO */
+			printk(KERN_ERR "unionfs: can't create a whiteout for "
+			       "%s in rename!\n", old_dentry->d_name.name);
+			err = -EIO;
+		}
+	}
+
+out:
+	return err;
+
+revert:
+	/* Do revert here. */
+	local_err = unionfs_refresh_lower_dentry(new_dentry, new_parent,
+						 old_bstart);
+	if (local_err) {
+		printk(KERN_ERR "unionfs: revert failed in rename: "
+		       "the new refresh failed\n");
+		eio = -EIO;
+	}
+
+	local_err = unionfs_refresh_lower_dentry(old_dentry, old_parent,
+						 old_bstart);
+	if (local_err) {
+		printk(KERN_ERR "unionfs: revert failed in rename: "
+		       "the old refresh failed\n");
+		eio = -EIO;
+		goto revert_out;
+	}
+
+	if (!unionfs_lower_dentry_idx(new_dentry, bindex) ||
+	    !unionfs_lower_dentry_idx(new_dentry, bindex)->d_inode) {
+		printk(KERN_ERR "unionfs: revert failed in rename: "
+		       "the object disappeared from under us!\n");
+		eio = -EIO;
+		goto revert_out;
+	}
+
+	if (unionfs_lower_dentry_idx(old_dentry, bindex) &&
+	    unionfs_lower_dentry_idx(old_dentry, bindex)->d_inode) {
+		printk(KERN_ERR "unionfs: revert failed in rename: "
+		       "the object was created underneath us!\n");
+		eio = -EIO;
+		goto revert_out;
+	}
+
+	local_err = __unionfs_rename(new_dir, new_dentry, new_parent,
+				     old_dir, old_dentry, old_parent,
+				     old_bstart);
+
+	/* If we can't fix it, then we cop-out with -EIO. */
+	if (local_err) {
+		printk(KERN_ERR "unionfs: revert failed in rename!\n");
+		eio = -EIO;
+	}
+
+	local_err = unionfs_refresh_lower_dentry(new_dentry, new_parent,
+						 bindex);
+	if (local_err)
+		eio = -EIO;
+	local_err = unionfs_refresh_lower_dentry(old_dentry, old_parent,
+						 bindex);
+	if (local_err)
+		eio = -EIO;
+
+revert_out:
+	if (eio)
+		err = eio;
+	return err;
+}
+
+/*
+ * We can't copyup a directory, because it may involve huge numbers of
+ * children, etc.  Doing that in the kernel would be bad, so instead we
+ * return EXDEV to the user-space utility that caused this, and let the
+ * user-space recurse and ask us to copy up each file separately.
+ */
+static int may_rename_dir(struct dentry *dentry, struct dentry *parent)
+{
+	int err, bstart;
+
+	err = check_empty(dentry, parent, NULL);
+	if (err == -ENOTEMPTY) {
+		if (is_robranch(dentry))
+			return -EXDEV;
+	} else if (err) {
+		return err;
+	}
+
+	bstart = dbstart(dentry);
+	if (dbend(dentry) == bstart || dbopaque(dentry) == bstart)
+		return 0;
+
+	dbstart(dentry) = bstart + 1;
+	err = check_empty(dentry, parent, NULL);
+	dbstart(dentry) = bstart;
+	if (err == -ENOTEMPTY)
+		err = -EXDEV;
+	return err;
+}
+
+/*
+ * The locking rules in unionfs_rename are complex.  We could use a simpler
+ * superblock-level name-space lock for renames and copy-ups.
+ */
+int unionfs_rename(struct inode *old_dir, struct dentry *old_dentry,
+		   struct inode *new_dir, struct dentry *new_dentry)
+{
+	int err = 0;
+	struct dentry *wh_dentry;
+	struct dentry *old_parent, *new_parent;
+	int valid = true;
+
+	unionfs_read_lock(old_dentry->d_sb, UNIONFS_SMUTEX_CHILD);
+	old_parent = dget_parent(old_dentry);
+	new_parent = dget_parent(new_dentry);
+	/* un/lock parent dentries only if they differ from old/new_dentry */
+	if (old_parent != old_dentry &&
+	    old_parent != new_dentry)
+		unionfs_lock_dentry(old_parent, UNIONFS_DMUTEX_REVAL_PARENT);
+	if (new_parent != old_dentry &&
+	    new_parent != new_dentry &&
+	    new_parent != old_parent)
+		unionfs_lock_dentry(new_parent, UNIONFS_DMUTEX_REVAL_CHILD);
+	unionfs_double_lock_dentry(old_dentry, new_dentry);
+
+	valid = __unionfs_d_revalidate(old_dentry, old_parent, false);
+	if (!valid) {
+		err = -ESTALE;
+		goto out;
+	}
+	if (!d_deleted(new_dentry) && new_dentry->d_inode) {
+		valid = __unionfs_d_revalidate(new_dentry, new_parent, false);
+		if (!valid) {
+			err = -ESTALE;
+			goto out;
+		}
+	}
+
+	if (!S_ISDIR(old_dentry->d_inode->i_mode))
+		err = unionfs_partial_lookup(old_dentry, old_parent);
+	else
+		err = may_rename_dir(old_dentry, old_parent);
+
+	if (err)
+		goto out;
+
+	err = unionfs_partial_lookup(new_dentry, new_parent);
+	if (err)
+		goto out;
+
+	/*
+	 * if new_dentry is already lower because of whiteout,
+	 * simply override it even if the whited-out dir is not empty.
+	 */
+	wh_dentry = find_first_whiteout(new_dentry);
+	if (!IS_ERR(wh_dentry)) {
+		dput(wh_dentry);
+	} else if (new_dentry->d_inode) {
+		if (S_ISDIR(old_dentry->d_inode->i_mode) !=
+		    S_ISDIR(new_dentry->d_inode->i_mode)) {
+			err = S_ISDIR(old_dentry->d_inode->i_mode) ?
+				-ENOTDIR : -EISDIR;
+			goto out;
+		}
+
+		if (S_ISDIR(new_dentry->d_inode->i_mode)) {
+			struct unionfs_dir_state *namelist = NULL;
+			/* check if this unionfs directory is empty or not */
+			err = check_empty(new_dentry, new_parent, &namelist);
+			if (err)
+				goto out;
+
+			if (!is_robranch(new_dentry))
+				err = delete_whiteouts(new_dentry,
+						       dbstart(new_dentry),
+						       namelist);
+
+			free_rdstate(namelist);
+
+			if (err)
+				goto out;
+		}
+	}
+
+	err = do_unionfs_rename(old_dir, old_dentry, old_parent,
+				new_dir, new_dentry, new_parent);
+	if (err)
+		goto out;
+
+	/*
+	 * force re-lookup since the dir on ro branch is not renamed, and
+	 * lower dentries still indicate the un-renamed ones.
+	 */
+	if (S_ISDIR(old_dentry->d_inode->i_mode))
+		atomic_dec(&UNIONFS_D(old_dentry)->generation);
+	else
+		unionfs_postcopyup_release(old_dentry);
+	if (new_dentry->d_inode && !S_ISDIR(new_dentry->d_inode->i_mode)) {
+		unionfs_postcopyup_release(new_dentry);
+		unionfs_postcopyup_setmnt(new_dentry);
+		if (!unionfs_lower_inode(new_dentry->d_inode)) {
+			/*
+			 * If we get here, it means that no copyup was
+			 * needed, and that a file by the old name already
+			 * existing on the destination branch; that file got
+			 * renamed earlier in this function, so all we need
+			 * to do here is set the lower inode.
+			 */
+			struct inode *inode;
+			inode = unionfs_lower_inode(old_dentry->d_inode);
+			igrab(inode);
+			unionfs_set_lower_inode_idx(new_dentry->d_inode,
+						    dbstart(new_dentry),
+						    inode);
+		}
+	}
+	/* if all of this renaming succeeded, update our times */
+	unionfs_copy_attr_times(old_dentry->d_inode);
+	unionfs_copy_attr_times(new_dentry->d_inode);
+	unionfs_check_inode(old_dir);
+	unionfs_check_inode(new_dir);
+	unionfs_check_dentry(old_dentry);
+	unionfs_check_dentry(new_dentry);
+
+out:
+	if (err)		/* clear the new_dentry stuff created */
+		d_drop(new_dentry);
+
+	unionfs_double_unlock_dentry(old_dentry, new_dentry);
+	if (new_parent != old_dentry &&
+	    new_parent != new_dentry &&
+	    new_parent != old_parent)
+		unionfs_unlock_dentry(new_parent);
+	if (old_parent != old_dentry &&
+	    old_parent != new_dentry)
+		unionfs_unlock_dentry(old_parent);
+	dput(new_parent);
+	dput(old_parent);
+	unionfs_read_unlock(old_dentry->d_sb);
+
+	return err;
+}