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Subject[PATCH 12/29] Unionfs: rename method and helpers
Date
Signed-off-by: Erez Zadok <ezk@cs.sunysb.edu>
---
fs/unionfs/rename.c | 531 +++++++++++++++++++++++++++++++++++++++++++++++++++
1 files changed, 531 insertions(+), 0 deletions(-)
create mode 100644 fs/unionfs/rename.c
diff --git a/fs/unionfs/rename.c b/fs/unionfs/rename.c
new file mode 100644
index 0000000..9306a2b
--- /dev/null
+++ b/fs/unionfs/rename.c
@@ -0,0 +1,531 @@
+/*
+ * Copyright (c) 2003-2007 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) 2003-2007 Stony Brook University
+ * Copyright (c) 2003-2007 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"
+
+static int __unionfs_rename(struct inode *old_dir, struct dentry *old_dentry,
+ struct inode *new_dir, struct dentry *new_dentry,
+ int bindex, struct dentry **wh_old)
+{
+ 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 *lower_wh_dentry;
+ struct dentry *lower_wh_dir_dentry;
+ char *wh_name = NULL;
+
+ 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_dentry->d_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;
+ }
+ }
+
+ wh_name = alloc_whname(new_dentry->d_name.name,
+ new_dentry->d_name.len);
+ if (unlikely(IS_ERR(wh_name))) {
+ err = PTR_ERR(wh_name);
+ goto out;
+ }
+
+ lower_wh_dentry = lookup_one_len(wh_name, lower_new_dentry->d_parent,
+ new_dentry->d_name.len +
+ UNIONFS_WHLEN);
+ if (IS_ERR(lower_wh_dentry)) {
+ err = PTR_ERR(lower_wh_dentry);
+ goto out;
+ }
+
+ if (lower_wh_dentry->d_inode) {
+ /* get rid of the whiteout that is existing */
+ if (lower_new_dentry->d_inode) {
+ printk(KERN_ERR "unionfs: both a whiteout and a "
+ "dentry exist when doing a rename!\n");
+ err = -EIO;
+
+ dput(lower_wh_dentry);
+ goto out;
+ }
+
+ lower_wh_dir_dentry = lock_parent_wh(lower_wh_dentry);
+ err = is_robranch_super(old_dentry->d_sb, bindex);
+ if (!err)
+ err = vfs_unlink(lower_wh_dir_dentry->d_inode,
+ lower_wh_dentry);
+
+ dput(lower_wh_dentry);
+ unlock_dir(lower_wh_dir_dentry);
+ if (err)
+ goto out;
+ } else {
+ dput(lower_wh_dentry);
+ }
+
+ err = is_robranch_super(old_dentry->d_sb, bindex);
+ if (err)
+ goto out;
+
+ dget(lower_old_dentry);
+ lower_old_dir_dentry = dget_parent(lower_old_dentry);
+ lower_new_dir_dentry = dget_parent(lower_new_dentry);
+
+ /*
+ * ready to whiteout for old_dentry. caller will create the actual
+ * whiteout, and must dput(*wh_old)
+ */
+ if (wh_old) {
+ char *whname;
+ whname = alloc_whname(old_dentry->d_name.name,
+ old_dentry->d_name.len);
+ err = PTR_ERR(whname);
+ if (unlikely(IS_ERR(whname)))
+ goto out_dput;
+ *wh_old = lookup_one_len(whname, lower_old_dir_dentry,
+ old_dentry->d_name.len +
+ UNIONFS_WHLEN);
+ kfree(whname);
+ err = PTR_ERR(*wh_old);
+ if (IS_ERR(*wh_old)) {
+ *wh_old = NULL;
+ goto out_dput;
+ }
+ }
+
+ /* see Documentation/filesystems/unionfs/issues.txt */
+ lockdep_off();
+ lock_rename(lower_old_dir_dentry, lower_new_dir_dentry);
+ err = vfs_rename(lower_old_dir_dentry->d_inode, lower_old_dentry,
+ lower_new_dir_dentry->d_inode, lower_new_dentry);
+ unlock_rename(lower_old_dir_dentry, lower_new_dir_dentry);
+ lockdep_on();
+
+out_dput:
+ dput(lower_old_dir_dentry);
+ dput(lower_new_dir_dentry);
+ dput(lower_old_dentry);
+
+out:
+ if (!err) {
+ /* Fixup the new_dentry. */
+ if (bindex < dbstart(new_dentry))
+ set_dbstart(new_dentry, bindex);
+ else if (bindex > dbend(new_dentry))
+ set_dbend(new_dentry, bindex);
+ }
+
+ kfree(wh_name);
+
+ 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 inode *new_dir,
+ struct dentry *new_dentry)
+{
+ int err = 0;
+ int bindex, bwh_old;
+ int old_bstart, old_bend;
+ int new_bstart, new_bend;
+ int do_copyup = -1;
+ struct dentry *parent_dentry;
+ int local_err = 0;
+ int eio = 0;
+ int revert = 0;
+ struct dentry *wh_old = NULL;
+
+ old_bstart = dbstart(old_dentry);
+ bwh_old = old_bstart;
+ old_bend = dbend(old_dentry);
+ parent_dentry = old_dentry->d_parent;
+
+ new_bstart = dbstart(new_dentry);
+ new_bend = dbend(new_dentry);
+
+ /* Rename source to destination. */
+ err = __unionfs_rename(old_dir, old_dentry, new_dir, new_dentry,
+ old_bstart, &wh_old);
+ 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;
+
+ 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_dentry->d_parent->d_inode,
+ unlink_dir_dentry->d_inode);
+ /* propagate number of hard-links */
+ new_dentry->d_parent->d_inode->i_nlink =
+ unionfs_get_nlinks(new_dentry->d_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) {
+ dput(wh_old);
+ 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_dentry->d_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;
+ dput(wh_old);
+ bwh_old = bindex;
+ err = __unionfs_rename(old_dir, old_dentry,
+ new_dir, new_dentry,
+ bindex, &wh_old);
+ 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.
+ * (2) We did a copy_up
+ */
+ if ((old_bstart != old_bend) || (do_copyup != -1)) {
+ struct dentry *lower_parent;
+ struct nameidata nd;
+ if (!wh_old || wh_old->d_inode || bwh_old < 0) {
+ printk(KERN_ERR "unionfs: rename error "
+ "(wh_old=%p/%p bwh_old=%d)\n", wh_old,
+ (wh_old ? wh_old->d_inode : NULL), bwh_old);
+ err = -EIO;
+ goto out;
+ }
+ err = init_lower_nd(&nd, LOOKUP_CREATE);
+ if (unlikely(err < 0))
+ goto out;
+ lower_parent = lock_parent_wh(wh_old);
+ local_err = vfs_create(lower_parent->d_inode, wh_old, S_IRUGO,
+ &nd);
+ unlock_dir(lower_parent);
+ if (!local_err) {
+ set_dbopaque(old_dentry, bwh_old);
+ } else {
+ /*
+ * we can't fix anything now, so we cop-out and use
+ * -EIO.
+ */
+ printk(KERN_ERR "unionfs: can't create a whiteout for "
+ "the source in rename!\n");
+ err = -EIO;
+ }
+ release_lower_nd(&nd, local_err);
+ }
+
+out:
+ dput(wh_old);
+ return err;
+
+revert:
+ /* Do revert here. */
+ local_err = unionfs_refresh_lower_dentry(new_dentry, 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_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,
+ old_dir, old_dentry, old_bstart, NULL);
+
+ /* 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, bindex);
+ if (local_err)
+ eio = -EIO;
+ local_err = unionfs_refresh_lower_dentry(old_dentry, bindex);
+ if (local_err)
+ eio = -EIO;
+
+revert_out:
+ if (eio)
+ err = eio;
+ return err;
+}
+
+static struct dentry *lookup_whiteout(struct dentry *dentry)
+{
+ char *whname;
+ int bindex = -1, bstart = -1, bend = -1;
+ struct dentry *parent, *lower_parent, *wh_dentry;
+
+ whname = alloc_whname(dentry->d_name.name, dentry->d_name.len);
+ if (unlikely(IS_ERR(whname)))
+ return (void *)whname;
+
+ parent = dget_parent(dentry);
+ unionfs_lock_dentry(parent, UNIONFS_DMUTEX_WHITEOUT);
+ bstart = dbstart(parent);
+ bend = dbend(parent);
+ wh_dentry = ERR_PTR(-ENOENT);
+ for (bindex = bstart; bindex <= bend; bindex++) {
+ lower_parent = unionfs_lower_dentry_idx(parent, bindex);
+ if (!lower_parent)
+ continue;
+ wh_dentry = lookup_one_len(whname, lower_parent,
+ dentry->d_name.len + UNIONFS_WHLEN);
+ if (IS_ERR(wh_dentry))
+ continue;
+ if (wh_dentry->d_inode)
+ break;
+ dput(wh_dentry);
+ wh_dentry = ERR_PTR(-ENOENT);
+ }
+ unionfs_unlock_dentry(parent);
+ dput(parent);
+ kfree(whname);
+ return wh_dentry;
+}
+
+/*
+ * 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)
+{
+ int err, bstart;
+
+ err = check_empty(dentry, 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;
+
+ set_dbstart(dentry, bstart + 1);
+ err = check_empty(dentry, NULL);
+ set_dbstart(dentry, bstart);
+ if (err == -ENOTEMPTY)
+ err = -EXDEV;
+ return err;
+}
+
+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;
+
+ unionfs_read_lock(old_dentry->d_sb, UNIONFS_SMUTEX_CHILD);
+ unionfs_double_lock_dentry(old_dentry, new_dentry);
+
+ if (unlikely(!__unionfs_d_revalidate_chain(old_dentry, NULL, false))) {
+ err = -ESTALE;
+ goto out;
+ }
+ if (unlikely(!d_deleted(new_dentry) && new_dentry->d_inode &&
+ !__unionfs_d_revalidate_chain(new_dentry, NULL, false))) {
+ err = -ESTALE;
+ goto out;
+ }
+
+ if (!S_ISDIR(old_dentry->d_inode->i_mode))
+ err = unionfs_partial_lookup(old_dentry);
+ else
+ err = may_rename_dir(old_dentry);
+
+ if (err)
+ goto out;
+
+ err = unionfs_partial_lookup(new_dentry);
+ 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 = lookup_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, &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, new_dir, new_dentry);
+ 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_dir);
+ unionfs_copy_attr_times(new_dir);
+ 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_unlock_dentry(new_dentry);
+ unionfs_unlock_dentry(old_dentry);
+ unionfs_read_unlock(old_dentry->d_sb);
+ return err;
+}
--
1.5.2.2


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