mirror of https://github.com/hak5/openwrt.git
268 lines
8.5 KiB
Diff
268 lines
8.5 KiB
Diff
From: Richard Weinberger <richard@nod.at>
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Date: Tue, 13 Sep 2016 16:18:57 +0200
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Subject: [PATCH] ubifs: Implement RENAME_EXCHANGE
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Adds RENAME_EXCHANGE to UBIFS, the operation itself
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is completely disjunct from a regular rename() that's
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why we dispatch very early in ubifs_reaname().
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RENAME_EXCHANGE used by the renameat2() system call
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allows the caller to exchange two paths atomically.
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Both paths have to exist and have to be on the same
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filesystem.
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Signed-off-by: Richard Weinberger <richard@nod.at>
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---
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--- a/fs/ubifs/dir.c
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+++ b/fs/ubifs/dir.c
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@@ -1095,11 +1095,6 @@ static int ubifs_rename(struct inode *ol
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old_dentry, old_inode->i_ino, old_dir->i_ino,
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new_dentry, new_dir->i_ino, flags);
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- if (flags & ~(RENAME_NOREPLACE | RENAME_WHITEOUT))
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- return -EINVAL;
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-
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- ubifs_assert(mutex_is_locked(&old_dir->i_mutex));
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- ubifs_assert(mutex_is_locked(&new_dir->i_mutex));
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if (unlink)
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ubifs_assert(mutex_is_locked(&new_inode->i_mutex));
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@@ -1284,6 +1279,64 @@ out_cancel:
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return err;
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}
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+static int ubifs_xrename(struct inode *old_dir, struct dentry *old_dentry,
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+ struct inode *new_dir, struct dentry *new_dentry)
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+{
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+ struct ubifs_info *c = old_dir->i_sb->s_fs_info;
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+ struct ubifs_budget_req req = { .new_dent = 1, .mod_dent = 1,
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+ .dirtied_ino = 2 };
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+ int sync = IS_DIRSYNC(old_dir) || IS_DIRSYNC(new_dir);
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+ struct inode *fst_inode = d_inode(old_dentry);
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+ struct inode *snd_inode = d_inode(new_dentry);
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+ struct timespec time;
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+ int err;
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+
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+ ubifs_assert(fst_inode && snd_inode);
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+
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+ lock_4_inodes(old_dir, new_dir, NULL, NULL);
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+
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+ time = ubifs_current_time(old_dir);
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+ fst_inode->i_ctime = time;
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+ snd_inode->i_ctime = time;
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+ old_dir->i_mtime = old_dir->i_ctime = time;
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+ new_dir->i_mtime = new_dir->i_ctime = time;
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+
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+ if (old_dir != new_dir) {
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+ if (S_ISDIR(fst_inode->i_mode) && !S_ISDIR(snd_inode->i_mode)) {
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+ inc_nlink(new_dir);
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+ drop_nlink(old_dir);
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+ }
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+ else if (!S_ISDIR(fst_inode->i_mode) && S_ISDIR(snd_inode->i_mode)) {
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+ drop_nlink(new_dir);
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+ inc_nlink(old_dir);
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+ }
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+ }
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+
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+ err = ubifs_jnl_xrename(c, old_dir, old_dentry, new_dir, new_dentry,
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+ sync);
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+
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+ unlock_4_inodes(old_dir, new_dir, NULL, NULL);
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+ ubifs_release_budget(c, &req);
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+
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+ return err;
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+}
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+
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+static int ubifs_rename2(struct inode *old_dir, struct dentry *old_dentry,
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+ struct inode *new_dir, struct dentry *new_dentry,
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+ unsigned int flags)
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+{
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+ if (flags & ~(RENAME_NOREPLACE | RENAME_WHITEOUT | RENAME_EXCHANGE))
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+ return -EINVAL;
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+
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+ ubifs_assert(mutex_is_locked(&old_dir->i_mutex));
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+ ubifs_assert(mutex_is_locked(&new_dir->i_mutex));
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+
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+ if (flags & RENAME_EXCHANGE)
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+ return ubifs_xrename(old_dir, old_dentry, new_dir, new_dentry);
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+
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+ return ubifs_rename(old_dir, old_dentry, new_dir, new_dentry, flags);
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+}
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+
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int ubifs_getattr(struct vfsmount *mnt, struct dentry *dentry,
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struct kstat *stat)
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{
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@@ -1332,7 +1385,7 @@ const struct inode_operations ubifs_dir_
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.mkdir = ubifs_mkdir,
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.rmdir = ubifs_rmdir,
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.mknod = ubifs_mknod,
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- .rename2 = ubifs_rename,
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+ .rename2 = ubifs_rename2,
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.setattr = ubifs_setattr,
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.getattr = ubifs_getattr,
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.setxattr = ubifs_setxattr,
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--- a/fs/ubifs/journal.c
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+++ b/fs/ubifs/journal.c
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@@ -908,6 +908,147 @@ int ubifs_jnl_delete_inode(struct ubifs_
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}
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/**
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+ * ubifs_jnl_xrename - cross rename two directory entries.
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+ * @c: UBIFS file-system description object
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+ * @fst_dir: parent inode of 1st directory entry to exchange
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+ * @fst_dentry: 1st directory entry to exchange
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+ * @snd_dir: parent inode of 2nd directory entry to exchange
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+ * @snd_dentry: 2nd directory entry to exchange
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+ * @sync: non-zero if the write-buffer has to be synchronized
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+ *
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+ * This function implements the cross rename operation which may involve
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+ * writing 2 inodes and 2 directory entries. It marks the written inodes as clean
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+ * and returns zero on success. In case of failure, a negative error code is
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+ * returned.
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+ */
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+int ubifs_jnl_xrename(struct ubifs_info *c, const struct inode *fst_dir,
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+ const struct dentry *fst_dentry,
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+ const struct inode *snd_dir,
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+ const struct dentry *snd_dentry, int sync)
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+{
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+ union ubifs_key key;
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+ struct ubifs_dent_node *dent1, *dent2;
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+ int err, dlen1, dlen2, lnum, offs, len, plen = UBIFS_INO_NODE_SZ;
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+ int aligned_dlen1, aligned_dlen2;
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+ int twoparents = (fst_dir != snd_dir);
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+ const struct inode *fst_inode = d_inode(fst_dentry);
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+ const struct inode *snd_inode = d_inode(snd_dentry);
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+ void *p;
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+
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+ dbg_jnl("dent '%pd' in dir ino %lu between dent '%pd' in dir ino %lu",
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+ fst_dentry, fst_dir->i_ino, snd_dentry, snd_dir->i_ino);
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+
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+ ubifs_assert(ubifs_inode(fst_dir)->data_len == 0);
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+ ubifs_assert(ubifs_inode(snd_dir)->data_len == 0);
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+ ubifs_assert(mutex_is_locked(&ubifs_inode(fst_dir)->ui_mutex));
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+ ubifs_assert(mutex_is_locked(&ubifs_inode(snd_dir)->ui_mutex));
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+
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+ dlen1 = UBIFS_DENT_NODE_SZ + snd_dentry->d_name.len + 1;
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+ dlen2 = UBIFS_DENT_NODE_SZ + fst_dentry->d_name.len + 1;
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+ aligned_dlen1 = ALIGN(dlen1, 8);
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+ aligned_dlen2 = ALIGN(dlen2, 8);
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+
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+ len = aligned_dlen1 + aligned_dlen2 + ALIGN(plen, 8);
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+ if (twoparents)
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+ len += plen;
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+
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+ dent1 = kmalloc(len, GFP_NOFS);
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+ if (!dent1)
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+ return -ENOMEM;
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+
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+ /* Make reservation before allocating sequence numbers */
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+ err = make_reservation(c, BASEHD, len);
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+ if (err)
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+ goto out_free;
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+
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+ /* Make new dent for 1st entry */
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+ dent1->ch.node_type = UBIFS_DENT_NODE;
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+ dent_key_init_flash(c, &dent1->key, snd_dir->i_ino, &snd_dentry->d_name);
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+ dent1->inum = cpu_to_le64(fst_inode->i_ino);
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+ dent1->type = get_dent_type(fst_inode->i_mode);
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+ dent1->nlen = cpu_to_le16(snd_dentry->d_name.len);
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+ memcpy(dent1->name, snd_dentry->d_name.name, snd_dentry->d_name.len);
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+ dent1->name[snd_dentry->d_name.len] = '\0';
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+ zero_dent_node_unused(dent1);
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+ ubifs_prep_grp_node(c, dent1, dlen1, 0);
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+
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+ /* Make new dent for 2nd entry */
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+ dent2 = (void *)dent1 + aligned_dlen1;
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+ dent2->ch.node_type = UBIFS_DENT_NODE;
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+ dent_key_init_flash(c, &dent2->key, fst_dir->i_ino, &fst_dentry->d_name);
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+ dent2->inum = cpu_to_le64(snd_inode->i_ino);
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+ dent2->type = get_dent_type(snd_inode->i_mode);
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+ dent2->nlen = cpu_to_le16(fst_dentry->d_name.len);
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+ memcpy(dent2->name, fst_dentry->d_name.name, fst_dentry->d_name.len);
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+ dent2->name[fst_dentry->d_name.len] = '\0';
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+ zero_dent_node_unused(dent2);
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+ ubifs_prep_grp_node(c, dent2, dlen2, 0);
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+
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+ p = (void *)dent2 + aligned_dlen2;
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+ if (!twoparents)
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+ pack_inode(c, p, fst_dir, 1);
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+ else {
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+ pack_inode(c, p, fst_dir, 0);
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+ p += ALIGN(plen, 8);
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+ pack_inode(c, p, snd_dir, 1);
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+ }
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+
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+ err = write_head(c, BASEHD, dent1, len, &lnum, &offs, sync);
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+ if (err)
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+ goto out_release;
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+ if (!sync) {
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+ struct ubifs_wbuf *wbuf = &c->jheads[BASEHD].wbuf;
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+
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+ ubifs_wbuf_add_ino_nolock(wbuf, fst_dir->i_ino);
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+ ubifs_wbuf_add_ino_nolock(wbuf, snd_dir->i_ino);
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+ }
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+ release_head(c, BASEHD);
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+
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+ dent_key_init(c, &key, snd_dir->i_ino, &snd_dentry->d_name);
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+ err = ubifs_tnc_add_nm(c, &key, lnum, offs, dlen1, &snd_dentry->d_name);
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+ if (err)
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+ goto out_ro;
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+
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+ offs += aligned_dlen1;
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+ dent_key_init(c, &key, fst_dir->i_ino, &fst_dentry->d_name);
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+ err = ubifs_tnc_add_nm(c, &key, lnum, offs, dlen2, &fst_dentry->d_name);
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+ if (err)
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+ goto out_ro;
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+
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+ offs += aligned_dlen2;
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+
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+ ino_key_init(c, &key, fst_dir->i_ino);
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+ err = ubifs_tnc_add(c, &key, lnum, offs, plen);
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+ if (err)
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+ goto out_ro;
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+
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+ if (twoparents) {
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+ offs += ALIGN(plen, 8);
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+ ino_key_init(c, &key, snd_dir->i_ino);
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+ err = ubifs_tnc_add(c, &key, lnum, offs, plen);
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+ if (err)
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+ goto out_ro;
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+ }
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+
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+ finish_reservation(c);
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+
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+ mark_inode_clean(c, ubifs_inode(fst_dir));
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+ if (twoparents)
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+ mark_inode_clean(c, ubifs_inode(snd_dir));
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+ kfree(dent1);
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+ return 0;
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+
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+out_release:
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+ release_head(c, BASEHD);
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+out_ro:
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+ ubifs_ro_mode(c, err);
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+ finish_reservation(c);
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+out_free:
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+ kfree(dent1);
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+ return err;
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+}
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+
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+/**
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* ubifs_jnl_rename - rename a directory entry.
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* @c: UBIFS file-system description object
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* @old_dir: parent inode of directory entry to rename
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--- a/fs/ubifs/ubifs.h
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+++ b/fs/ubifs/ubifs.h
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@@ -1544,6 +1544,10 @@ int ubifs_jnl_write_data(struct ubifs_in
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const union ubifs_key *key, const void *buf, int len);
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int ubifs_jnl_write_inode(struct ubifs_info *c, const struct inode *inode);
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int ubifs_jnl_delete_inode(struct ubifs_info *c, const struct inode *inode);
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+int ubifs_jnl_xrename(struct ubifs_info *c, const struct inode *fst_dir,
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+ const struct dentry *fst_dentry,
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+ const struct inode *snd_dir,
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+ const struct dentry *snd_dentry, int sync);
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int ubifs_jnl_rename(struct ubifs_info *c, const struct inode *old_dir,
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const struct dentry *old_dentry,
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const struct inode *new_dir,
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