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Subject[PATCH 5 of 23] Unionfs: Copyup Functionality
Date
From
From: Josef "Jeff" Sipek <jsipek@cs.sunysb.edu>

This patch contains the functions used to perform copyup operations in unionfs.

Signed-off-by: Josef "Jeff" Sipek <jsipek@cs.sunysb.edu>
Signed-off-by: David Quigley <dquigley@fsl.cs.sunysb.edu>
Signed-off-by: Erez Zadok <ezk@cs.sunysb.edu>

---
1 file changed, 657 insertions(+)
fs/unionfs/copyup.c | 657 +++++++++++++++++++++++++++++++++++++++++++++++++++
diff -r fd7639f798f9 -r 2bae4a1f2233 fs/unionfs/copyup.c
--- /dev/null Thu Jan 01 00:00:00 1970 +0000
+++ b/fs/unionfs/copyup.c Sat Oct 07 00:46:18 2006 -0400
@@ -0,0 +1,657 @@
+/*
+ * Copyright (c) 2003-2006 Erez Zadok
+ * Copyright (c) 2003-2006 Charles P. Wright
+ * Copyright (c) 2005-2006 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) 2003-2006 Stony Brook University
+ * Copyright (c) 2003-2006 The Research Foundation of State University of New York*
+ *
+ * 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"
+
+/* Determine the mode based on the copyup flags, and the existing dentry. */
+static int copyup_permissions(struct super_block *sb,
+ struct dentry *old_hidden_dentry,
+ struct dentry *new_hidden_dentry)
+{
+ struct inode *i = old_hidden_dentry->d_inode;
+ struct iattr newattrs;
+ int err;
+
+ newattrs.ia_atime = i->i_atime;
+ newattrs.ia_mtime = i->i_mtime;
+ newattrs.ia_ctime = i->i_ctime;
+
+ newattrs.ia_gid = i->i_gid;
+ newattrs.ia_uid = i->i_uid;
+
+ newattrs.ia_mode = i->i_mode;
+
+ newattrs.ia_valid = ATTR_CTIME | ATTR_ATIME | ATTR_MTIME |
+ ATTR_ATIME_SET | ATTR_MTIME_SET | ATTR_FORCE |
+ ATTR_GID | ATTR_UID | ATTR_MODE;
+
+ err = notify_change(new_hidden_dentry, &newattrs);
+
+ return err;
+}
+
+int copyup_dentry(struct inode *dir, struct dentry *dentry,
+ int bstart, int new_bindex,
+ struct file **copyup_file, loff_t len)
+{
+ return copyup_named_dentry(dir, dentry, bstart, new_bindex,
+ dentry->d_name.name,
+ dentry->d_name.len, copyup_file, len);
+}
+
+/* create the new device/file/directory - use copyup_permission to copyup
+ * times, and mode
+ *
+ * if the object being copied up is a regular file, the file is only created,
+ * the contents have to be copied up separately
+ */
+static inline int __copyup_ndentry(struct dentry *old_hidden_dentry,
+ struct dentry *new_hidden_dentry,
+ struct dentry *new_hidden_parent_dentry,
+ char *symbuf)
+{
+ int err = 0;
+ umode_t old_mode = old_hidden_dentry->d_inode->i_mode;
+ struct sioq_args args;
+
+ if (S_ISDIR(old_mode)) {
+ args.u.mkdir.parent = new_hidden_parent_dentry->d_inode;
+ args.u.mkdir.dentry = new_hidden_dentry;
+ args.u.mkdir.mode = old_mode;
+
+ run_sioq(__unionfs_mkdir, &args);
+ err = args.err;
+ } else if (S_ISLNK(old_mode)) {
+ args.u.symlink.parent = new_hidden_parent_dentry->d_inode;
+ args.u.symlink.dentry = new_hidden_dentry;
+ args.u.symlink.symbuf = symbuf;
+ args.u.symlink.mode = old_mode;
+
+ run_sioq(__unionfs_symlink, &args);
+ err = args.err;
+ } else if (S_ISBLK(old_mode)
+ || S_ISCHR(old_mode)
+ || S_ISFIFO(old_mode)
+ || S_ISSOCK(old_mode)) {
+ args.u.mknod.parent = new_hidden_parent_dentry->d_inode;
+ args.u.mknod.dentry = new_hidden_dentry;
+ args.u.mknod.mode = old_mode;
+ args.u.mknod.dev = old_hidden_dentry->d_inode->i_rdev;
+
+ run_sioq(__unionfs_mknod, &args);
+ err = args.err;
+ } else if (S_ISREG(old_mode)) {
+ args.u.create.parent = new_hidden_parent_dentry->d_inode;
+ args.u.create.dentry = new_hidden_dentry;
+ args.u.create.mode = old_mode;
+ args.u.create.nd = NULL;
+
+ run_sioq(__unionfs_create, &args);
+ err = args.err;
+ } else {
+ printk(KERN_ERR "Unknown inode type %d\n",
+ old_mode);
+ BUG();
+ }
+
+ return err;
+}
+
+static inline int __copyup_reg_data(struct dentry *dentry,
+ struct dentry *new_hidden_dentry,
+ int new_bindex,
+ struct dentry *old_hidden_dentry,
+ int old_bindex,
+ struct file **copyup_file,
+ loff_t len)
+{
+ struct super_block *sb = dentry->d_sb;
+ struct file *input_file;
+ struct file *output_file;
+ mm_segment_t old_fs;
+ char *buf = NULL;
+ ssize_t read_bytes, write_bytes;
+ ssize_t size;
+ int err = 0;
+
+ /* open old file */
+ mntget(dtohm_index(dentry, old_bindex));
+ branchget(sb, old_bindex);
+ input_file = dentry_open(old_hidden_dentry,
+ dtohm_index(dentry, old_bindex), O_RDONLY);
+ if (IS_ERR(input_file)) {
+ dput(old_hidden_dentry);
+ err = PTR_ERR(input_file);
+ goto out;
+ }
+ if (!input_file->f_op || !input_file->f_op->read) {
+ err = -EINVAL;
+ goto out_close_in;
+ }
+
+ /* open new file */
+ dget(new_hidden_dentry);
+ mntget(dtohm_index(dentry, new_bindex));
+ branchget(sb, new_bindex);
+ output_file = dentry_open(new_hidden_dentry,
+ dtohm_index(dentry, new_bindex), O_WRONLY);
+ if (IS_ERR(output_file)) {
+ err = PTR_ERR(output_file);
+ goto out_close_in2;
+ }
+ if (!output_file->f_op || !output_file->f_op->write) {
+ err = -EINVAL;
+ goto out_close_out;
+ }
+
+ /* allocating a buffer */
+ buf = kmalloc(PAGE_SIZE, GFP_KERNEL);
+ if (!buf) {
+ err = -ENOMEM;
+ goto out_close_out;
+ }
+
+ input_file->f_pos = 0;
+ output_file->f_pos = 0;
+
+ old_fs = get_fs();
+ set_fs(KERNEL_DS);
+
+ size = len;
+ err = 0;
+ do {
+ if (len >= PAGE_SIZE)
+ size = PAGE_SIZE;
+ else if ((len < PAGE_SIZE) && (len > 0))
+ size = len;
+
+ len -= PAGE_SIZE;
+
+ read_bytes =
+ input_file->f_op->read(input_file,
+ (char __user *)buf, size,
+ &input_file->f_pos);
+ if (read_bytes <= 0) {
+ err = read_bytes;
+ break;
+ }
+
+ write_bytes =
+ output_file->f_op->write(output_file,
+ (char __user *)buf,
+ read_bytes,
+ &output_file->f_pos);
+ if (write_bytes < 0 || (write_bytes < read_bytes)) {
+ err = write_bytes;
+ break;
+ }
+ } while ((read_bytes > 0) && (len > 0));
+
+ set_fs(old_fs);
+
+ kfree(buf);
+
+ if (err)
+ goto out_close_out;
+ if (copyup_file) {
+ *copyup_file = output_file;
+ goto out_close_in;
+ }
+
+out_close_out:
+ fput(output_file);
+
+out_close_in2:
+ branchput(sb, new_bindex);
+
+out_close_in:
+ fput(input_file);
+
+out:
+ branchput(sb, old_bindex);
+
+ return err;
+}
+
+static inline void __clear(struct dentry *dentry,
+ struct dentry *old_hidden_dentry,
+ int old_bstart, int old_bend,
+ struct dentry *new_hidden_dentry,
+ int new_bindex)
+{
+ /* get rid of the hidden dentry and all its traces */
+ set_dtohd_index(dentry, new_bindex, NULL);
+ set_dbstart(dentry, old_bstart);
+ set_dbend(dentry, old_bend);
+
+ dput(new_hidden_dentry);
+ dput(old_hidden_dentry);
+}
+
+int copyup_named_dentry(struct inode *dir, struct dentry *dentry,
+ int bstart, int new_bindex, const char *name,
+ int namelen, struct file **copyup_file, loff_t len)
+{
+ struct dentry *new_hidden_dentry;
+ struct dentry *old_hidden_dentry = NULL;
+ struct super_block *sb;
+ int err = 0;
+ int old_bindex;
+ int old_bstart;
+ int old_bend;
+ struct dentry *new_hidden_parent_dentry = NULL;
+ mm_segment_t oldfs;
+ char *symbuf = NULL;
+
+ verify_locked(dentry);
+
+ old_bindex = bstart;
+ old_bstart = dbstart(dentry);
+ old_bend = dbend(dentry);
+
+ BUG_ON(new_bindex < 0);
+ BUG_ON(new_bindex >= old_bindex);
+
+ sb = dir->i_sb;
+
+ unionfs_read_lock(sb);
+
+ if ((err = is_robranch_super(sb, new_bindex))) {
+ dput(old_hidden_dentry);
+ goto out;
+ }
+
+ /* Create the directory structure above this dentry. */
+ new_hidden_dentry = create_parents_named(dir, dentry, name, new_bindex);
+ if (IS_ERR(new_hidden_dentry)) {
+ dput(old_hidden_dentry);
+ err = PTR_ERR(new_hidden_dentry);
+ goto out;
+ }
+
+ old_hidden_dentry = dtohd_index(dentry, old_bindex);
+ dget(old_hidden_dentry);
+
+ /* For symlinks, we must read the link before we lock the directory. */
+ if (S_ISLNK(old_hidden_dentry->d_inode->i_mode)) {
+
+ symbuf = kmalloc(PATH_MAX, GFP_KERNEL);
+ if (!symbuf) {
+ __clear(dentry, old_hidden_dentry,
+ old_bstart, old_bend,
+ new_hidden_dentry, new_bindex);
+ err = -ENOMEM;
+ goto out_free;
+ }
+
+ oldfs = get_fs();
+ set_fs(KERNEL_DS);
+ err = old_hidden_dentry->d_inode->i_op->readlink(
+ old_hidden_dentry,
+ (char __user *)symbuf,
+ PATH_MAX);
+ set_fs(oldfs);
+ if (err) {
+ __clear(dentry, old_hidden_dentry,
+ old_bstart, old_bend,
+ new_hidden_dentry, new_bindex);
+ goto out_free;
+ }
+ symbuf[err] = '\0';
+ }
+
+ /* Now we lock the parent, and create the object in the new branch. */
+ new_hidden_parent_dentry = lock_parent(new_hidden_dentry);
+
+ /* create the new inode */
+ err = __copyup_ndentry(old_hidden_dentry, new_hidden_dentry,
+ new_hidden_parent_dentry, symbuf);
+
+ if (err) {
+ __clear(dentry, old_hidden_dentry,
+ old_bstart, old_bend,
+ new_hidden_dentry, new_bindex);
+ goto out_unlock;
+ }
+
+ /* We actually copyup the file here. */
+ if (S_ISREG(old_hidden_dentry->d_inode->i_mode))
+ err = __copyup_reg_data(dentry, new_hidden_dentry, new_bindex,
+ old_hidden_dentry, old_bindex, copyup_file, len);
+ if (err)
+ goto out_unlink;
+
+ /* Set permissions. */
+ if ((err = copyup_permissions(sb, old_hidden_dentry, new_hidden_dentry)))
+ goto out_unlink;
+
+ /* do not allow files getting deleted to be reinterposed */
+ if (!d_deleted(dentry))
+ unionfs_reinterpose(dentry);
+
+ goto out_unlock;
+ /****/
+
+out_unlink:
+ /* copyup failed, because we possibly ran out of space or
+ * quota, or something else happened so let's unlink; we don't
+ * really care about the return value of vfs_unlink */
+ vfs_unlink(new_hidden_parent_dentry->d_inode, new_hidden_dentry);
+
+ if (copyup_file) {
+ /* need to close the file */
+
+ fput(*copyup_file);
+ branchput(sb, new_bindex);
+ }
+
+ /* TODO: should we reset the error to something like -EIO? */
+
+out_unlock:
+ unlock_dir(new_hidden_parent_dentry);
+
+out_free:
+ kfree(symbuf);
+
+out:
+ unionfs_read_unlock(sb);
+
+ return err;
+}
+
+/* This function creates a copy of a file represented by 'file' which currently
+ * resides in branch 'bstart' to branch 'new_bindex.' The copy will be named
+ * "name". */
+int copyup_named_file(struct inode *dir, struct file *file, char *name,
+ int bstart, int new_bindex, loff_t len)
+{
+ int err = 0;
+ struct file *output_file = NULL;
+
+ err = copyup_named_dentry(dir, file->f_dentry, bstart,
+ new_bindex, name, strlen(name), &output_file,
+ len);
+ if (!err) {
+ fbstart(file) = new_bindex;
+ set_ftohf_index(file, new_bindex, output_file);
+ }
+
+ return err;
+}
+
+/* This function creates a copy of a file represented by 'file' which currently
+ * resides in branch 'bstart' to branch 'new_bindex'.
+ */
+int copyup_file(struct inode *dir, struct file *file, int bstart,
+ int new_bindex, loff_t len)
+{
+ int err = 0;
+ struct file *output_file = NULL;
+
+ err = copyup_dentry(dir, file->f_dentry, bstart, new_bindex,
+ &output_file, len);
+ if (!err) {
+ fbstart(file) = new_bindex;
+ set_ftohf_index(file, new_bindex, output_file);
+ }
+
+ return err;
+}
+
+/* This function replicates the directory structure upto given dentry
+ * in the bindex branch. Can create directory structure recursively to the right
+ * also.
+ */
+struct dentry *create_parents(struct inode *dir, struct dentry *dentry,
+ int bindex)
+{
+ return create_parents_named(dir, dentry, dentry->d_name.name, bindex);
+}
+
+static inline void __cleanup_dentry(struct dentry * dentry, int bindex,
+ int old_bstart, int old_bend)
+{
+ int loop_start;
+ int loop_end;
+ int new_bstart = -1;
+ int new_bend = -1;
+ int i;
+
+ loop_start = min(old_bstart, bindex);
+ loop_end = max(old_bend, bindex);
+
+ /* This loop sets the bstart and bend for the new
+ * dentry by traversing from left to right.
+ * It also dputs all negative dentries except
+ * bindex (the newly looked dentry
+ */
+ for (i = loop_start; i <= loop_end; i++) {
+ if (!dtohd_index(dentry, i))
+ continue;
+
+ if (i == bindex) {
+ new_bend = i;
+ if (new_bstart < 0)
+ new_bstart = i;
+ continue;
+ }
+
+ if (!dtohd_index(dentry, i)->d_inode) {
+ dput(dtohd_index(dentry, i));
+ set_dtohd_index(dentry, i, NULL);
+ } else {
+ if (new_bstart < 0)
+ new_bstart = i;
+ new_bend = i;
+ }
+ }
+
+ if (new_bstart < 0)
+ new_bstart = bindex;
+ if (new_bend < 0)
+ new_bend = bindex;
+ set_dbstart(dentry, new_bstart);
+ set_dbend(dentry, new_bend);
+
+}
+static inline void __set_inode(struct dentry * upper, struct dentry * lower,
+ int bindex)
+{
+ set_itohi_index(upper->d_inode, bindex,
+ igrab(lower->d_inode));
+ if (likely(ibstart(upper->d_inode) > bindex))
+ ibstart(upper->d_inode) = bindex;
+ if (likely(ibend(upper->d_inode) < bindex))
+ ibend(upper->d_inode) = bindex;
+
+}
+static inline void __set_dentry(struct dentry * upper, struct dentry * lower,
+ int bindex)
+{
+ set_dtohd_index(upper, bindex, lower);
+ if (likely(dbstart(upper) > bindex))
+ set_dbstart(upper, bindex);
+ if (likely(dbend(upper) < bindex))
+ set_dbend(upper, bindex);
+}
+/* This function replicates the directory structure upto given dentry
+ * in the bindex branch. */
+struct dentry *create_parents_named(struct inode *dir, struct dentry *dentry,
+ const char *name, int bindex)
+{
+ int err;
+ struct dentry *child_dentry;
+ struct dentry *parent_dentry;
+ struct dentry *hidden_parent_dentry = NULL;
+ struct dentry *hidden_dentry = NULL;
+ const char *childname;
+ unsigned int childnamelen;
+
+ int old_kmalloc_size;
+ int kmalloc_size;
+ int num_dentry;
+ int count;
+
+ int old_bstart;
+ int old_bend;
+ struct dentry **path = NULL;
+ struct dentry **tmp_path;
+ struct super_block *sb;
+
+ verify_locked(dentry);
+
+ /* There is no sense allocating any less than the minimum. */
+ kmalloc_size = malloc_sizes[0].cs_size;
+ num_dentry = kmalloc_size / sizeof(struct dentry *);
+
+ if ((err = is_robranch_super(dir->i_sb, bindex))) {
+ hidden_dentry = ERR_PTR(err);
+ goto out;
+ }
+
+ old_bstart = dbstart(dentry);
+ old_bend = dbend(dentry);
+
+ hidden_dentry = ERR_PTR(-ENOMEM);
+ path = kzalloc(kmalloc_size, GFP_KERNEL);
+ if (!path)
+ goto out;
+
+ /* assume the negative dentry of unionfs as the parent dentry */
+ parent_dentry = dentry;
+
+ count = 0;
+ /* This loop finds the first parent that exists in the given branch.
+ * We start building the directory structure from there. At the end
+ * of the loop, the following should hold:
+ * child_dentry is the first nonexistent child
+ * parent_dentry is the first existent parent
+ * path[0] is the = deepest child
+ * path[count] is the first child to create
+ */
+ do {
+ child_dentry = parent_dentry;
+
+ /* find the parent directory dentry in unionfs */
+ parent_dentry = child_dentry->d_parent;
+ lock_dentry(parent_dentry);
+
+ /* find out the hidden_parent_dentry in the given branch */
+ hidden_parent_dentry = dtohd_index(parent_dentry, bindex);
+
+ /* store the child dentry */
+ path[count++] = child_dentry;
+
+ /* grow path table */
+ if (count == num_dentry) {
+ old_kmalloc_size = kmalloc_size;
+ kmalloc_size *= 2;
+ num_dentry = kmalloc_size / sizeof(struct dentry *);
+
+ tmp_path = kzalloc(kmalloc_size, GFP_KERNEL);
+ if (!tmp_path) {
+ hidden_dentry = ERR_PTR(-ENOMEM);
+ goto out;
+ }
+ memcpy(tmp_path, path, old_kmalloc_size);
+ kfree(path);
+ path = tmp_path;
+ tmp_path = NULL;
+ }
+
+ } while (!hidden_parent_dentry);
+ count--;
+
+ sb = dentry->d_sb;
+
+ /* This is basically while(child_dentry != dentry). This loop is
+ * horrible to follow and should be replaced with cleaner code. */
+ while (1) {
+ // get hidden parent dir in the current branch
+ hidden_parent_dentry = dtohd_index(parent_dentry, bindex);
+ unlock_dentry(parent_dentry);
+
+ // init the values to lookup
+ childname = child_dentry->d_name.name;
+ childnamelen = child_dentry->d_name.len;
+
+ if (child_dentry != dentry) {
+ // lookup child in the underlying file system
+ hidden_dentry =
+ lookup_one_len(childname, hidden_parent_dentry,
+ childnamelen);
+ if (IS_ERR(hidden_dentry))
+ goto out;
+ } else {
+
+ /* is the name a whiteout of the childname ? */
+ //lookup the whiteout child in the underlying file system
+ hidden_dentry =
+ lookup_one_len(name, hidden_parent_dentry,
+ strlen(name));
+ if (IS_ERR(hidden_dentry))
+ goto out;
+
+ /* Replace the current dentry (if any) with the new one. */
+ dput(dtohd_index(dentry, bindex));
+ set_dtohd_index(dentry, bindex, hidden_dentry);
+
+ __cleanup_dentry(dentry, bindex, old_bstart, old_bend);
+ break;
+ }
+
+ if (hidden_dentry->d_inode) {
+ /* since this already exists we dput to avoid
+ * multiple references on the same dentry */
+ dput(hidden_dentry);
+ } else {
+ struct sioq_args args;
+
+ /* its a negative dentry, create a new dir */
+ hidden_parent_dentry = lock_parent(hidden_dentry);
+
+ args.u.mkdir.parent = hidden_parent_dentry->d_inode;
+ args.u.mkdir.dentry = hidden_dentry;
+ args.u.mkdir.mode = child_dentry->d_inode->i_mode;
+
+ run_sioq(__unionfs_mkdir, &args);
+ err = args.err;
+
+ if (!err)
+ err = copyup_permissions(dir->i_sb,
+ child_dentry, hidden_dentry);
+ unlock_dir(hidden_parent_dentry);
+ if (err) {
+ dput(hidden_dentry);
+ hidden_dentry = ERR_PTR(err);
+ goto out;
+ }
+
+ }
+
+ __set_inode(child_dentry, hidden_dentry, bindex);
+ __set_dentry(child_dentry, hidden_dentry, bindex);
+
+ parent_dentry = child_dentry;
+ child_dentry = path[--count];
+ }
+out:
+ kfree(path);
+ return hidden_dentry;
+}
+

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