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authorFelix Fietkau <nbd@nbd.name>2016-09-14 10:15:40 +0200
committerFelix Fietkau <nbd@nbd.name>2016-09-19 14:27:26 +0200
commit413eb04e1eeff0ea140b0dd5365ae04fb0dabd46 (patch)
treead8caea967e61829de00509c2466f54fe33bcc8d /target/linux/generic
parent41a582a986595ed4e20c3e2969f31a041390e4f6 (diff)
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ubifs: add full overlayfs support
Signed-off-by: Felix Fietkau <nbd@nbd.name>
Diffstat (limited to 'target/linux/generic')
-rw-r--r--target/linux/generic/patches-4.4/052-01-ubifs-Implement-O_TMPFILE.patch99
-rw-r--r--target/linux/generic/patches-4.4/052-02-ubifs-Implement-RENAME_WHITEOUT.patch342
-rw-r--r--target/linux/generic/patches-4.4/052-03-ubifs-Implement-RENAME_EXCHANGE.patch267
-rw-r--r--target/linux/generic/patches-4.4/052-04-ubifs-Use-move-variable-in-ubifs_rename.patch30
4 files changed, 738 insertions, 0 deletions
diff --git a/target/linux/generic/patches-4.4/052-01-ubifs-Implement-O_TMPFILE.patch b/target/linux/generic/patches-4.4/052-01-ubifs-Implement-O_TMPFILE.patch
new file mode 100644
index 0000000..957935c
--- /dev/null
+++ b/target/linux/generic/patches-4.4/052-01-ubifs-Implement-O_TMPFILE.patch
@@ -0,0 +1,99 @@
+From: Richard Weinberger <richard@nod.at>
+Date: Tue, 13 Sep 2016 16:18:55 +0200
+Subject: [PATCH] ubifs: Implement O_TMPFILE
+
+This patchs adds O_TMPFILE support to UBIFS.
+A temp file is a reference to an unlinked inode, a user
+holding the reference can use it. As soon it is being closed
+all data vanishes.
+
+Signed-off-by: Richard Weinberger <richard@nod.at>
+---
+
+--- a/fs/ubifs/dir.c
++++ b/fs/ubifs/dir.c
+@@ -301,6 +301,76 @@ out_budg:
+ return err;
+ }
+
++static int ubifs_tmpfile(struct inode *dir, struct dentry *dentry,
++ umode_t mode)
++{
++ struct inode *inode;
++ struct ubifs_info *c = dir->i_sb->s_fs_info;
++ struct ubifs_budget_req req = { .new_ino = 1, .new_dent = 1};
++ struct ubifs_budget_req ino_req = { .dirtied_ino = 1 };
++ struct ubifs_inode *ui, *dir_ui = ubifs_inode(dir);
++ int err, instantiated = 0;
++
++ /*
++ * Budget request settings: new dirty inode, new direntry,
++ * budget for dirtied inode will be released via writeback.
++ */
++
++ dbg_gen("dent '%pd', mode %#hx in dir ino %lu",
++ dentry, mode, dir->i_ino);
++
++ err = ubifs_budget_space(c, &req);
++ if (err)
++ return err;
++
++ err = ubifs_budget_space(c, &ino_req);
++ if (err) {
++ ubifs_release_budget(c, &req);
++ return err;
++ }
++
++ inode = ubifs_new_inode(c, dir, mode);
++ if (IS_ERR(inode)) {
++ err = PTR_ERR(inode);
++ goto out_budg;
++ }
++ ui = ubifs_inode(inode);
++
++ err = ubifs_init_security(dir, inode, &dentry->d_name);
++ if (err)
++ goto out_inode;
++
++ mutex_lock(&ui->ui_mutex);
++ insert_inode_hash(inode);
++ d_tmpfile(dentry, inode);
++ ubifs_assert(ui->dirty);
++ instantiated = 1;
++ mutex_unlock(&ui->ui_mutex);
++
++ mutex_lock(&dir_ui->ui_mutex);
++ err = ubifs_jnl_update(c, dir, &dentry->d_name, inode, 1, 0);
++ if (err)
++ goto out_cancel;
++ mutex_unlock(&dir_ui->ui_mutex);
++
++ ubifs_release_budget(c, &req);
++
++ return 0;
++
++out_cancel:
++ mutex_unlock(&dir_ui->ui_mutex);
++out_inode:
++ make_bad_inode(inode);
++ if (!instantiated)
++ iput(inode);
++out_budg:
++ ubifs_release_budget(c, &req);
++ if (!instantiated)
++ ubifs_release_budget(c, &ino_req);
++ ubifs_err(c, "cannot create temporary file, error %d", err);
++ return err;
++}
++
+ /**
+ * vfs_dent_type - get VFS directory entry type.
+ * @type: UBIFS directory entry type
+@@ -1189,6 +1259,7 @@ const struct inode_operations ubifs_dir_
+ #ifdef CONFIG_UBIFS_ATIME_SUPPORT
+ .update_time = ubifs_update_time,
+ #endif
++ .tmpfile = ubifs_tmpfile,
+ };
+
+ const struct file_operations ubifs_dir_operations = {
diff --git a/target/linux/generic/patches-4.4/052-02-ubifs-Implement-RENAME_WHITEOUT.patch b/target/linux/generic/patches-4.4/052-02-ubifs-Implement-RENAME_WHITEOUT.patch
new file mode 100644
index 0000000..9abb923
--- /dev/null
+++ b/target/linux/generic/patches-4.4/052-02-ubifs-Implement-RENAME_WHITEOUT.patch
@@ -0,0 +1,342 @@
+From: Richard Weinberger <richard@nod.at>
+Date: Tue, 13 Sep 2016 16:18:56 +0200
+Subject: [PATCH] ubifs: Implement RENAME_WHITEOUT
+
+Adds RENAME_WHITEOUT support to UBIFS, we implement
+it in the same way as ext4 and xfs do.
+For an overview of other ways to implement it please
+refere to commit 7dcf5c3e4527 ("xfs: add RENAME_WHITEOUT support").
+
+Signed-off-by: Richard Weinberger <richard@nod.at>
+---
+
+--- a/fs/ubifs/dir.c
++++ b/fs/ubifs/dir.c
+@@ -301,8 +301,8 @@ out_budg:
+ return err;
+ }
+
+-static int ubifs_tmpfile(struct inode *dir, struct dentry *dentry,
+- umode_t mode)
++static int do_tmpfile(struct inode *dir, struct dentry *dentry,
++ umode_t mode, struct inode **whiteout)
+ {
+ struct inode *inode;
+ struct ubifs_info *c = dir->i_sb->s_fs_info;
+@@ -336,14 +336,27 @@ static int ubifs_tmpfile(struct inode *d
+ }
+ ui = ubifs_inode(inode);
+
++ if (whiteout) {
++ init_special_inode(inode, inode->i_mode, WHITEOUT_DEV);
++ ubifs_assert(inode->i_op == &ubifs_file_inode_operations);
++ }
++
+ err = ubifs_init_security(dir, inode, &dentry->d_name);
+ if (err)
+ goto out_inode;
+
+ mutex_lock(&ui->ui_mutex);
+ insert_inode_hash(inode);
+- d_tmpfile(dentry, inode);
++
++ if (whiteout) {
++ mark_inode_dirty(inode);
++ drop_nlink(inode);
++ *whiteout = inode;
++ } else {
++ d_tmpfile(dentry, inode);
++ }
+ ubifs_assert(ui->dirty);
++
+ instantiated = 1;
+ mutex_unlock(&ui->ui_mutex);
+
+@@ -371,6 +384,12 @@ out_budg:
+ return err;
+ }
+
++static int ubifs_tmpfile(struct inode *dir, struct dentry *dentry,
++ umode_t mode)
++{
++ return do_tmpfile(dir, dentry, mode, NULL);
++}
++
+ /**
+ * vfs_dent_type - get VFS directory entry type.
+ * @type: UBIFS directory entry type
+@@ -997,37 +1016,43 @@ out_budg:
+ }
+
+ /**
+- * lock_3_inodes - a wrapper for locking three UBIFS inodes.
++ * lock_4_inodes - a wrapper for locking three UBIFS inodes.
+ * @inode1: first inode
+ * @inode2: second inode
+ * @inode3: third inode
++ * @inode4: fouth inode
+ *
+ * This function is used for 'ubifs_rename()' and @inode1 may be the same as
+- * @inode2 whereas @inode3 may be %NULL.
++ * @inode2 whereas @inode3 and @inode4 may be %NULL.
+ *
+ * We do not implement any tricks to guarantee strict lock ordering, because
+ * VFS has already done it for us on the @i_mutex. So this is just a simple
+ * wrapper function.
+ */
+-static void lock_3_inodes(struct inode *inode1, struct inode *inode2,
+- struct inode *inode3)
++static void lock_4_inodes(struct inode *inode1, struct inode *inode2,
++ struct inode *inode3, struct inode *inode4)
+ {
+ mutex_lock_nested(&ubifs_inode(inode1)->ui_mutex, WB_MUTEX_1);
+ if (inode2 != inode1)
+ mutex_lock_nested(&ubifs_inode(inode2)->ui_mutex, WB_MUTEX_2);
+ if (inode3)
+ mutex_lock_nested(&ubifs_inode(inode3)->ui_mutex, WB_MUTEX_3);
++ if (inode4)
++ mutex_lock_nested(&ubifs_inode(inode4)->ui_mutex, WB_MUTEX_4);
+ }
+
+ /**
+- * unlock_3_inodes - a wrapper for unlocking three UBIFS inodes for rename.
++ * unlock_4_inodes - a wrapper for unlocking three UBIFS inodes for rename.
+ * @inode1: first inode
+ * @inode2: second inode
+ * @inode3: third inode
++ * @inode4: fouth inode
+ */
+-static void unlock_3_inodes(struct inode *inode1, struct inode *inode2,
+- struct inode *inode3)
++static void unlock_4_inodes(struct inode *inode1, struct inode *inode2,
++ struct inode *inode3, struct inode *inode4)
+ {
++ if (inode4)
++ mutex_unlock(&ubifs_inode(inode4)->ui_mutex);
+ if (inode3)
+ mutex_unlock(&ubifs_inode(inode3)->ui_mutex);
+ if (inode1 != inode2)
+@@ -1036,12 +1061,15 @@ static void unlock_3_inodes(struct inode
+ }
+
+ static int ubifs_rename(struct inode *old_dir, struct dentry *old_dentry,
+- struct inode *new_dir, struct dentry *new_dentry)
++ struct inode *new_dir, struct dentry *new_dentry,
++ unsigned int flags)
+ {
+ struct ubifs_info *c = old_dir->i_sb->s_fs_info;
+ struct inode *old_inode = d_inode(old_dentry);
+ struct inode *new_inode = d_inode(new_dentry);
++ struct inode *whiteout = NULL;
+ struct ubifs_inode *old_inode_ui = ubifs_inode(old_inode);
++ struct ubifs_inode *whiteout_ui = NULL;
+ int err, release, sync = 0, move = (new_dir != old_dir);
+ int is_dir = S_ISDIR(old_inode->i_mode);
+ int unlink = !!new_inode;
+@@ -1063,9 +1091,13 @@ static int ubifs_rename(struct inode *ol
+ * separately.
+ */
+
+- dbg_gen("dent '%pd' ino %lu in dir ino %lu to dent '%pd' in dir ino %lu",
++ dbg_gen("dent '%pd' ino %lu in dir ino %lu to dent '%pd' in dir ino %lu flags 0x%x",
+ old_dentry, old_inode->i_ino, old_dir->i_ino,
+- new_dentry, new_dir->i_ino);
++ new_dentry, new_dir->i_ino, flags);
++
++ if (flags & ~(RENAME_NOREPLACE | RENAME_WHITEOUT))
++ return -EINVAL;
++
+ ubifs_assert(mutex_is_locked(&old_dir->i_mutex));
+ ubifs_assert(mutex_is_locked(&new_dir->i_mutex));
+ if (unlink)
+@@ -1087,7 +1119,32 @@ static int ubifs_rename(struct inode *ol
+ return err;
+ }
+
+- lock_3_inodes(old_dir, new_dir, new_inode);
++ if (flags & RENAME_WHITEOUT) {
++ union ubifs_dev_desc *dev = NULL;
++
++ dev = kmalloc(sizeof(union ubifs_dev_desc), GFP_NOFS);
++ if (!dev) {
++ ubifs_release_budget(c, &req);
++ ubifs_release_budget(c, &ino_req);
++ return -ENOMEM;
++ }
++
++ err = do_tmpfile(old_dir, old_dentry, S_IFCHR | WHITEOUT_MODE, &whiteout);
++ if (err) {
++ ubifs_release_budget(c, &req);
++ ubifs_release_budget(c, &ino_req);
++ kfree(dev);
++ return err;
++ }
++
++ whiteout->i_state |= I_LINKABLE;
++ whiteout_ui = ubifs_inode(whiteout);
++ whiteout_ui->data = dev;
++ whiteout_ui->data_len = ubifs_encode_dev(dev, MKDEV(0, 0));
++ ubifs_assert(!whiteout_ui->dirty);
++ }
++
++ lock_4_inodes(old_dir, new_dir, new_inode, whiteout);
+
+ /*
+ * Like most other Unix systems, set the @i_ctime for inodes on a
+@@ -1157,12 +1214,34 @@ static int ubifs_rename(struct inode *ol
+ if (unlink && IS_SYNC(new_inode))
+ sync = 1;
+ }
+- err = ubifs_jnl_rename(c, old_dir, old_dentry, new_dir, new_dentry,
++
++ if (whiteout) {
++ struct ubifs_budget_req wht_req = { .dirtied_ino = 1,
++ .dirtied_ino_d = \
++ ALIGN(ubifs_inode(whiteout)->data_len, 8) };
++
++ err = ubifs_budget_space(c, &wht_req);
++ if (err) {
++ ubifs_release_budget(c, &req);
++ ubifs_release_budget(c, &ino_req);
++ kfree(whiteout_ui->data);
++ whiteout_ui->data_len = 0;
++ iput(whiteout);
++ return err;
++ }
++
++ inc_nlink(whiteout);
++ mark_inode_dirty(whiteout);
++ whiteout->i_state &= ~I_LINKABLE;
++ iput(whiteout);
++ }
++
++ err = ubifs_jnl_rename(c, old_dir, old_dentry, new_dir, new_dentry, whiteout,
+ sync);
+ if (err)
+ goto out_cancel;
+
+- unlock_3_inodes(old_dir, new_dir, new_inode);
++ unlock_4_inodes(old_dir, new_dir, new_inode, whiteout);
+ ubifs_release_budget(c, &req);
+
+ mutex_lock(&old_inode_ui->ui_mutex);
+@@ -1195,7 +1274,11 @@ out_cancel:
+ inc_nlink(old_dir);
+ }
+ }
+- unlock_3_inodes(old_dir, new_dir, new_inode);
++ if (whiteout) {
++ drop_nlink(whiteout);
++ iput(whiteout);
++ }
++ unlock_4_inodes(old_dir, new_dir, new_inode, whiteout);
+ ubifs_release_budget(c, &ino_req);
+ ubifs_release_budget(c, &req);
+ return err;
+@@ -1249,7 +1332,7 @@ const struct inode_operations ubifs_dir_
+ .mkdir = ubifs_mkdir,
+ .rmdir = ubifs_rmdir,
+ .mknod = ubifs_mknod,
+- .rename = ubifs_rename,
++ .rename2 = ubifs_rename,
+ .setattr = ubifs_setattr,
+ .getattr = ubifs_getattr,
+ .setxattr = ubifs_setxattr,
+--- a/fs/ubifs/journal.c
++++ b/fs/ubifs/journal.c
+@@ -917,14 +917,15 @@ int ubifs_jnl_delete_inode(struct ubifs_
+ * @sync: non-zero if the write-buffer has to be synchronized
+ *
+ * This function implements the re-name operation which may involve writing up
+- * to 3 inodes and 2 directory entries. It marks the written inodes as clean
++ * to 4 inodes and 2 directory entries. It marks the written inodes as clean
+ * and returns zero on success. In case of failure, a negative error code is
+ * returned.
+ */
+ int ubifs_jnl_rename(struct ubifs_info *c, const struct inode *old_dir,
+ const struct dentry *old_dentry,
+ const struct inode *new_dir,
+- const struct dentry *new_dentry, int sync)
++ const struct dentry *new_dentry,
++ const struct inode *whiteout, int sync)
+ {
+ void *p;
+ union ubifs_key key;
+@@ -980,13 +981,19 @@ int ubifs_jnl_rename(struct ubifs_info *
+ zero_dent_node_unused(dent);
+ ubifs_prep_grp_node(c, dent, dlen1, 0);
+
+- /* Make deletion dent */
+ dent2 = (void *)dent + aligned_dlen1;
+ dent2->ch.node_type = UBIFS_DENT_NODE;
+ dent_key_init_flash(c, &dent2->key, old_dir->i_ino,
+ &old_dentry->d_name);
+- dent2->inum = 0;
+- dent2->type = DT_UNKNOWN;
++
++ if (whiteout) {
++ dent2->inum = cpu_to_le64(whiteout->i_ino);
++ dent2->type = get_dent_type(whiteout->i_mode);
++ } else {
++ /* Make deletion dent */
++ dent2->inum = 0;
++ dent2->type = DT_UNKNOWN;
++ }
+ dent2->nlen = cpu_to_le16(old_dentry->d_name.len);
+ memcpy(dent2->name, old_dentry->d_name.name, old_dentry->d_name.len);
+ dent2->name[old_dentry->d_name.len] = '\0';
+@@ -1035,16 +1042,26 @@ int ubifs_jnl_rename(struct ubifs_info *
+ if (err)
+ goto out_ro;
+
+- err = ubifs_add_dirt(c, lnum, dlen2);
+- if (err)
+- goto out_ro;
++ offs += aligned_dlen1;
++ if (whiteout) {
++ dent_key_init(c, &key, old_dir->i_ino, &old_dentry->d_name);
++ err = ubifs_tnc_add_nm(c, &key, lnum, offs, dlen2, &old_dentry->d_name);
++ if (err)
++ goto out_ro;
+
+- dent_key_init(c, &key, old_dir->i_ino, &old_dentry->d_name);
+- err = ubifs_tnc_remove_nm(c, &key, &old_dentry->d_name);
+- if (err)
+- goto out_ro;
++ ubifs_delete_orphan(c, whiteout->i_ino);
++ } else {
++ err = ubifs_add_dirt(c, lnum, dlen2);
++ if (err)
++ goto out_ro;
+
+- offs += aligned_dlen1 + aligned_dlen2;
++ dent_key_init(c, &key, old_dir->i_ino, &old_dentry->d_name);
++ err = ubifs_tnc_remove_nm(c, &key, &old_dentry->d_name);
++ if (err)
++ goto out_ro;
++ }
++
++ offs += aligned_dlen2;
+ if (new_inode) {
+ ino_key_init(c, &key, new_inode->i_ino);
+ err = ubifs_tnc_add(c, &key, lnum, offs, ilen);
+--- a/fs/ubifs/ubifs.h
++++ b/fs/ubifs/ubifs.h
+@@ -180,6 +180,7 @@ enum {
+ WB_MUTEX_1 = 0,
+ WB_MUTEX_2 = 1,
+ WB_MUTEX_3 = 2,
++ WB_MUTEX_4 = 3,
+ };
+
+ /*
+@@ -1546,7 +1547,8 @@ int ubifs_jnl_delete_inode(struct ubifs_
+ int ubifs_jnl_rename(struct ubifs_info *c, const struct inode *old_dir,
+ const struct dentry *old_dentry,
+ const struct inode *new_dir,
+- const struct dentry *new_dentry, int sync);
++ const struct dentry *new_dentry,
++ const struct inode *whiteout, int sync);
+ int ubifs_jnl_truncate(struct ubifs_info *c, const struct inode *inode,
+ loff_t old_size, loff_t new_size);
+ int ubifs_jnl_delete_xattr(struct ubifs_info *c, const struct inode *host,
diff --git a/target/linux/generic/patches-4.4/052-03-ubifs-Implement-RENAME_EXCHANGE.patch b/target/linux/generic/patches-4.4/052-03-ubifs-Implement-RENAME_EXCHANGE.patch
new file mode 100644
index 0000000..20856c3
--- /dev/null
+++ b/target/linux/generic/patches-4.4/052-03-ubifs-Implement-RENAME_EXCHANGE.patch
@@ -0,0 +1,267 @@
+From: Richard Weinberger <richard@nod.at>
+Date: Tue, 13 Sep 2016 16:18:57 +0200
+Subject: [PATCH] ubifs: Implement RENAME_EXCHANGE
+
+Adds RENAME_EXCHANGE to UBIFS, the operation itself
+is completely disjunct from a regular rename() that's
+why we dispatch very early in ubifs_reaname().
+
+RENAME_EXCHANGE used by the renameat2() system call
+allows the caller to exchange two paths atomically.
+Both paths have to exist and have to be on the same
+filesystem.
+
+Signed-off-by: Richard Weinberger <richard@nod.at>
+---
+
+--- a/fs/ubifs/dir.c
++++ b/fs/ubifs/dir.c
+@@ -1095,11 +1095,6 @@ static int ubifs_rename(struct inode *ol
+ old_dentry, old_inode->i_ino, old_dir->i_ino,
+ new_dentry, new_dir->i_ino, flags);
+
+- if (flags & ~(RENAME_NOREPLACE | RENAME_WHITEOUT))
+- return -EINVAL;
+-
+- ubifs_assert(mutex_is_locked(&old_dir->i_mutex));
+- ubifs_assert(mutex_is_locked(&new_dir->i_mutex));
+ if (unlink)
+ ubifs_assert(mutex_is_locked(&new_inode->i_mutex));
+
+@@ -1284,6 +1279,64 @@ out_cancel:
+ return err;
+ }
+
++static int ubifs_xrename(struct inode *old_dir, struct dentry *old_dentry,
++ struct inode *new_dir, struct dentry *new_dentry)
++{
++ struct ubifs_info *c = old_dir->i_sb->s_fs_info;
++ struct ubifs_budget_req req = { .new_dent = 1, .mod_dent = 1,
++ .dirtied_ino = 2 };
++ int sync = IS_DIRSYNC(old_dir) || IS_DIRSYNC(new_dir);
++ struct inode *fst_inode = d_inode(old_dentry);
++ struct inode *snd_inode = d_inode(new_dentry);
++ struct timespec time;
++ int err;
++
++ ubifs_assert(fst_inode && snd_inode);
++
++ lock_4_inodes(old_dir, new_dir, NULL, NULL);
++
++ time = ubifs_current_time(old_dir);
++ fst_inode->i_ctime = time;
++ snd_inode->i_ctime = time;
++ old_dir->i_mtime = old_dir->i_ctime = time;
++ new_dir->i_mtime = new_dir->i_ctime = time;
++
++ if (old_dir != new_dir) {
++ if (S_ISDIR(fst_inode->i_mode) && !S_ISDIR(snd_inode->i_mode)) {
++ inc_nlink(new_dir);
++ drop_nlink(old_dir);
++ }
++ else if (!S_ISDIR(fst_inode->i_mode) && S_ISDIR(snd_inode->i_mode)) {
++ drop_nlink(new_dir);
++ inc_nlink(old_dir);
++ }
++ }
++
++ err = ubifs_jnl_xrename(c, old_dir, old_dentry, new_dir, new_dentry,
++ sync);
++
++ unlock_4_inodes(old_dir, new_dir, NULL, NULL);
++ ubifs_release_budget(c, &req);
++
++ return err;
++}
++
++static int ubifs_rename2(struct inode *old_dir, struct dentry *old_dentry,
++ struct inode *new_dir, struct dentry *new_dentry,
++ unsigned int flags)
++{
++ if (flags & ~(RENAME_NOREPLACE | RENAME_WHITEOUT | RENAME_EXCHANGE))
++ return -EINVAL;
++
++ ubifs_assert(mutex_is_locked(&old_dir->i_mutex));
++ ubifs_assert(mutex_is_locked(&new_dir->i_mutex));
++
++ if (flags & RENAME_EXCHANGE)
++ return ubifs_xrename(old_dir, old_dentry, new_dir, new_dentry);
++
++ return ubifs_rename(old_dir, old_dentry, new_dir, new_dentry, flags);
++}
++
+ int ubifs_getattr(struct vfsmount *mnt, struct dentry *dentry,
+ struct kstat *stat)
+ {
+@@ -1332,7 +1385,7 @@ const struct inode_operations ubifs_dir_
+ .mkdir = ubifs_mkdir,
+ .rmdir = ubifs_rmdir,
+ .mknod = ubifs_mknod,
+- .rename2 = ubifs_rename,
++ .rename2 = ubifs_rename2,
+ .setattr = ubifs_setattr,
+ .getattr = ubifs_getattr,
+ .setxattr = ubifs_setxattr,
+--- a/fs/ubifs/journal.c
++++ b/fs/ubifs/journal.c
+@@ -908,6 +908,147 @@ int ubifs_jnl_delete_inode(struct ubifs_
+ }
+
+ /**
++ * ubifs_jnl_xrename - cross rename two directory entries.
++ * @c: UBIFS file-system description object
++ * @fst_dir: parent inode of 1st directory entry to exchange
++ * @fst_dentry: 1st directory entry to exchange
++ * @snd_dir: parent inode of 2nd directory entry to exchange
++ * @snd_dentry: 2nd directory entry to exchange
++ * @sync: non-zero if the write-buffer has to be synchronized
++ *
++ * This function implements the cross rename operation which may involve
++ * writing 2 inodes and 2 directory entries. It marks the written inodes as clean
++ * and returns zero on success. In case of failure, a negative error code is
++ * returned.
++ */
++int ubifs_jnl_xrename(struct ubifs_info *c, const struct inode *fst_dir,
++ const struct dentry *fst_dentry,
++ const struct inode *snd_dir,
++ const struct dentry *snd_dentry, int sync)
++{
++ union ubifs_key key;
++ struct ubifs_dent_node *dent1, *dent2;
++ int err, dlen1, dlen2, lnum, offs, len, plen = UBIFS_INO_NODE_SZ;
++ int aligned_dlen1, aligned_dlen2;
++ int twoparents = (fst_dir != snd_dir);
++ const struct inode *fst_inode = d_inode(fst_dentry);
++ const struct inode *snd_inode = d_inode(snd_dentry);
++ void *p;
++
++ dbg_jnl("dent '%pd' in dir ino %lu between dent '%pd' in dir ino %lu",
++ fst_dentry, fst_dir->i_ino, snd_dentry, snd_dir->i_ino);
++
++ ubifs_assert(ubifs_inode(fst_dir)->data_len == 0);
++ ubifs_assert(ubifs_inode(snd_dir)->data_len == 0);
++ ubifs_assert(mutex_is_locked(&ubifs_inode(fst_dir)->ui_mutex));
++ ubifs_assert(mutex_is_locked(&ubifs_inode(snd_dir)->ui_mutex));
++
++ dlen1 = UBIFS_DENT_NODE_SZ + snd_dentry->d_name.len + 1;
++ dlen2 = UBIFS_DENT_NODE_SZ + fst_dentry->d_name.len + 1;
++ aligned_dlen1 = ALIGN(dlen1, 8);
++ aligned_dlen2 = ALIGN(dlen2, 8);
++
++ len = aligned_dlen1 + aligned_dlen2 + ALIGN(plen, 8);
++ if (twoparents)
++ len += plen;
++
++ dent1 = kmalloc(len, GFP_NOFS);
++ if (!dent1)
++ return -ENOMEM;
++
++ /* Make reservation before allocating sequence numbers */
++ err = make_reservation(c, BASEHD, len);
++ if (err)
++ goto out_free;
++
++ /* Make new dent for 1st entry */
++ dent1->ch.node_type = UBIFS_DENT_NODE;
++ dent_key_init_flash(c, &dent1->key, snd_dir->i_ino, &snd_dentry->d_name);
++ dent1->inum = cpu_to_le64(fst_inode->i_ino);
++ dent1->type = get_dent_type(fst_inode->i_mode);
++ dent1->nlen = cpu_to_le16(snd_dentry->d_name.len);
++ memcpy(dent1->name, snd_dentry->d_name.name, snd_dentry->d_name.len);
++ dent1->name[snd_dentry->d_name.len] = '\0';
++ zero_dent_node_unused(dent1);
++ ubifs_prep_grp_node(c, dent1, dlen1, 0);
++
++ /* Make new dent for 2nd entry */
++ dent2 = (void *)dent1 + aligned_dlen1;
++ dent2->ch.node_type = UBIFS_DENT_NODE;
++ dent_key_init_flash(c, &dent2->key, fst_dir->i_ino, &fst_dentry->d_name);
++ dent2->inum = cpu_to_le64(snd_inode->i_ino);
++ dent2->type = get_dent_type(snd_inode->i_mode);
++ dent2->nlen = cpu_to_le16(fst_dentry->d_name.len);
++ memcpy(dent2->name, fst_dentry->d_name.name, fst_dentry->d_name.len);
++ dent2->name[fst_dentry->d_name.len] = '\0';
++ zero_dent_node_unused(dent2);
++ ubifs_prep_grp_node(c, dent2, dlen2, 0);
++
++ p = (void *)dent2 + aligned_dlen2;
++ if (!twoparents)
++ pack_inode(c, p, fst_dir, 1);
++ else {
++ pack_inode(c, p, fst_dir, 0);
++ p += ALIGN(plen, 8);
++ pack_inode(c, p, snd_dir, 1);
++ }
++
++ err = write_head(c, BASEHD, dent1, len, &lnum, &offs, sync);
++ if (err)
++ goto out_release;
++ if (!sync) {
++ struct ubifs_wbuf *wbuf = &c->jheads[BASEHD].wbuf;
++
++ ubifs_wbuf_add_ino_nolock(wbuf, fst_dir->i_ino);
++ ubifs_wbuf_add_ino_nolock(wbuf, snd_dir->i_ino);
++ }
++ release_head(c, BASEHD);
++
++ dent_key_init(c, &key, snd_dir->i_ino, &snd_dentry->d_name);
++ err = ubifs_tnc_add_nm(c, &key, lnum, offs, dlen1, &snd_dentry->d_name);
++ if (err)
++ goto out_ro;
++
++ offs += aligned_dlen1;
++ dent_key_init(c, &key, fst_dir->i_ino, &fst_dentry->d_name);
++ err = ubifs_tnc_add_nm(c, &key, lnum, offs, dlen2, &fst_dentry->d_name);
++ if (err)
++ goto out_ro;
++
++ offs += aligned_dlen2;
++
++ ino_key_init(c, &key, fst_dir->i_ino);
++ err = ubifs_tnc_add(c, &key, lnum, offs, plen);
++ if (err)
++ goto out_ro;
++
++ if (twoparents) {
++ offs += ALIGN(plen, 8);
++ ino_key_init(c, &key, snd_dir->i_ino);
++ err = ubifs_tnc_add(c, &key, lnum, offs, plen);
++ if (err)
++ goto out_ro;
++ }
++
++ finish_reservation(c);
++
++ mark_inode_clean(c, ubifs_inode(fst_dir));
++ if (twoparents)
++ mark_inode_clean(c, ubifs_inode(snd_dir));
++ kfree(dent1);
++ return 0;
++
++out_release:
++ release_head(c, BASEHD);
++out_ro:
++ ubifs_ro_mode(c, err);
++ finish_reservation(c);
++out_free:
++ kfree(dent1);
++ return err;
++}
++
++/**
+ * ubifs_jnl_rename - rename a directory entry.
+ * @c: UBIFS file-system description object
+ * @old_dir: parent inode of directory entry to rename
+--- a/fs/ubifs/ubifs.h
++++ b/fs/ubifs/ubifs.h
+@@ -1544,6 +1544,10 @@ int ubifs_jnl_write_data(struct ubifs_in
+ const union ubifs_key *key, const void *buf, int len);
+ int ubifs_jnl_write_inode(struct ubifs_info *c, const struct inode *inode);
+ int ubifs_jnl_delete_inode(struct ubifs_info *c, const struct inode *inode);
++int ubifs_jnl_xrename(struct ubifs_info *c, const struct inode *fst_dir,
++ const struct dentry *fst_dentry,
++ const struct inode *snd_dir,
++ const struct dentry *snd_dentry, int sync);
+ int ubifs_jnl_rename(struct ubifs_info *c, const struct inode *old_dir,
+ const struct dentry *old_dentry,
+ const struct inode *new_dir,
diff --git a/target/linux/generic/patches-4.4/052-04-ubifs-Use-move-variable-in-ubifs_rename.patch b/target/linux/generic/patches-4.4/052-04-ubifs-Use-move-variable-in-ubifs_rename.patch
new file mode 100644
index 0000000..8112935
--- /dev/null
+++ b/target/linux/generic/patches-4.4/052-04-ubifs-Use-move-variable-in-ubifs_rename.patch
@@ -0,0 +1,30 @@
+From: Richard Weinberger <richard@nod.at>
+Date: Tue, 13 Sep 2016 16:18:58 +0200
+Subject: [PATCH] ubifs: Use move variable in ubifs_rename()
+
+...to make the code more consistent since we use
+move already in other places.
+
+Signed-off-by: Richard Weinberger <richard@nod.at>
+---
+
+--- a/fs/ubifs/journal.c
++++ b/fs/ubifs/journal.c
+@@ -1100,7 +1100,7 @@ int ubifs_jnl_rename(struct ubifs_info *
+ aligned_dlen1 = ALIGN(dlen1, 8);
+ aligned_dlen2 = ALIGN(dlen2, 8);
+ len = aligned_dlen1 + aligned_dlen2 + ALIGN(ilen, 8) + ALIGN(plen, 8);
+- if (old_dir != new_dir)
++ if (move)
+ len += plen;
+ dent = kmalloc(len, GFP_NOFS);
+ if (!dent)
+@@ -1216,7 +1216,7 @@ int ubifs_jnl_rename(struct ubifs_info *
+ if (err)
+ goto out_ro;
+
+- if (old_dir != new_dir) {
++ if (move) {
+ offs += ALIGN(plen, 8);
+ ino_key_init(c, &key, new_dir->i_ino);
+ err = ubifs_tnc_add(c, &key, lnum, offs, plen);