ext4: let add_dir_entry handle inline data properly

This patch let add_dir_entry handle the inline data case. So the
dir is initialized as inline dir first and then we can try to add
some files to it, when the inline space can't hold all the entries,
a dir block will be created and the dir entry will be moved to it.

Also for an inlined dir, "." and ".." are removed and we only use
4 bytes to store the parent inode number. These 2 entries will be
added when we convert an inline dir to a block-based one.

[ Folded in patch from Dan Carpenter to remove an unused variable. ]

Signed-off-by: Tao Ma <boyu.mt@taobao.com>
Signed-off-by: Dan Carpenter <dan.carpenter@oracle.com>
Signed-off-by: "Theodore Ts'o" <tytso@mit.edu>

1 files changed, 377 insertions, 0 deletions

diff --git a/fs/ext4/inline.c b/fs/ext4/inline.c
index 65f7ffb5437f..bf7322818738 100644
--- a/fs/ext4/inline.c
+++ b/fs/ext4/inline.c
@@ -18,6 +18,7 @@
 
 #define EXT4_XATTR_SYSTEM_DATA	"data"
 #define EXT4_MIN_INLINE_DATA_SIZE	((sizeof(__le32) * EXT4_N_BLOCKS))
+#define EXT4_INLINE_DOTDOT_SIZE	4
 
 int ext4_get_inline_size(struct inode *inode)
 {
@@ -949,6 +950,382 @@ int ext4_da_write_inline_data_end(struct inode *inode, loff_t pos,
 	return copied;
 }
 
+#ifdef INLINE_DIR_DEBUG
+void ext4_show_inline_dir(struct inode *dir, struct buffer_head *bh,
+			  void *inline_start, int inline_size)
+{
+	int offset;
+	unsigned short de_len;
+	struct ext4_dir_entry_2 *de = inline_start;
+	void *dlimit = inline_start + inline_size;
+
+	trace_printk("inode %lu\n", dir->i_ino);
+	offset = 0;
+	while ((void *)de < dlimit) {
+		de_len = ext4_rec_len_from_disk(de->rec_len, inline_size);
+		trace_printk("de: off %u rlen %u name %*.s nlen %u ino %u\n",
+			     offset, de_len, de->name_len, de->name,
+			     de->name_len, le32_to_cpu(de->inode));
+		if (ext4_check_dir_entry(dir, NULL, de, bh,
+					 inline_start, inline_size, offset))
+			BUG();
+
+		offset += de_len;
+		de = (struct ext4_dir_entry_2 *) ((char *) de + de_len);
+	}
+}
+#else
+#define ext4_show_inline_dir(dir, bh, inline_start, inline_size)
+#endif
+
+/*
+ * Add a new entry into a inline dir.
+ * It will return -ENOSPC if no space is available, and -EIO
+ * and -EEXIST if directory entry already exists.
+ */
+static int ext4_add_dirent_to_inline(handle_t *handle,
+				     struct dentry *dentry,
+				     struct inode *inode,
+				     struct ext4_iloc *iloc,
+				     void *inline_start, int inline_size)
+{
+	struct inode	*dir = dentry->d_parent->d_inode;
+	const char	*name = dentry->d_name.name;
+	int		namelen = dentry->d_name.len;
+	unsigned short	reclen;
+	int		err;
+	struct ext4_dir_entry_2 *de;
+
+	reclen = EXT4_DIR_REC_LEN(namelen);
+	err = ext4_find_dest_de(dir, inode, iloc->bh,
+				inline_start, inline_size,
+				name, namelen, &de);
+	if (err)
+		return err;
+
+	err = ext4_journal_get_write_access(handle, iloc->bh);
+	if (err)
+		return err;
+	ext4_insert_dentry(inode, de, inline_size, name, namelen);
+
+	ext4_show_inline_dir(dir, iloc->bh, inline_start, inline_size);
+
+	/*
+	 * XXX shouldn't update any times until successful
+	 * completion of syscall, but too many callers depend
+	 * on this.
+	 *
+	 * XXX similarly, too many callers depend on
+	 * ext4_new_inode() setting the times, but error
+	 * recovery deletes the inode, so the worst that can
+	 * happen is that the times are slightly out of date
+	 * and/or different from the directory change time.
+	 */
+	dir->i_mtime = dir->i_ctime = ext4_current_time(dir);
+	ext4_update_dx_flag(dir);
+	dir->i_version++;
+	ext4_mark_inode_dirty(handle, dir);
+	return 1;
+}
+
+static void *ext4_get_inline_xattr_pos(struct inode *inode,
+				       struct ext4_iloc *iloc)
+{
+	struct ext4_xattr_entry *entry;
+	struct ext4_xattr_ibody_header *header;
+
+	BUG_ON(!EXT4_I(inode)->i_inline_off);
+
+	header = IHDR(inode, ext4_raw_inode(iloc));
+	entry = (struct ext4_xattr_entry *)((void *)ext4_raw_inode(iloc) +
+					    EXT4_I(inode)->i_inline_off);
+
+	return (void *)IFIRST(header) + le16_to_cpu(entry->e_value_offs);
+}
+
+/* Set the final de to cover the whole block. */
+static void ext4_update_final_de(void *de_buf, int old_size, int new_size)
+{
+	struct ext4_dir_entry_2 *de, *prev_de;
+	void *limit;
+	int de_len;
+
+	de = (struct ext4_dir_entry_2 *)de_buf;
+	if (old_size) {
+		limit = de_buf + old_size;
+		do {
+			prev_de = de;
+			de_len = ext4_rec_len_from_disk(de->rec_len, old_size);
+			de_buf += de_len;
+			de = (struct ext4_dir_entry_2 *)de_buf;
+		} while (de_buf < limit);
+
+		prev_de->rec_len = ext4_rec_len_to_disk(de_len + new_size -
+							old_size, new_size);
+	} else {
+		/* this is just created, so create an empty entry. */
+		de->inode = 0;
+		de->rec_len = ext4_rec_len_to_disk(new_size, new_size);
+	}
+}
+
+static int ext4_update_inline_dir(handle_t *handle, struct inode *dir,
+				  struct ext4_iloc *iloc)
+{
+	int ret;
+	int old_size = EXT4_I(dir)->i_inline_size - EXT4_MIN_INLINE_DATA_SIZE;
+	int new_size = get_max_inline_xattr_value_size(dir, iloc);
+
+	if (new_size - old_size <= EXT4_DIR_REC_LEN(1))
+		return -ENOSPC;
+
+	ret = ext4_update_inline_data(handle, dir,
+				      new_size + EXT4_MIN_INLINE_DATA_SIZE);
+	if (ret)
+		return ret;
+
+	ext4_update_final_de(ext4_get_inline_xattr_pos(dir, iloc), old_size,
+			     EXT4_I(dir)->i_inline_size -
+						EXT4_MIN_INLINE_DATA_SIZE);
+	dir->i_size = EXT4_I(dir)->i_disksize = EXT4_I(dir)->i_inline_size;
+	return 0;
+}
+
+static void ext4_restore_inline_data(handle_t *handle, struct inode *inode,
+				     struct ext4_iloc *iloc,
+				     void *buf, int inline_size)
+{
+	ext4_create_inline_data(handle, inode, inline_size);
+	ext4_write_inline_data(inode, iloc, buf, 0, inline_size);
+	ext4_set_inode_state(inode, EXT4_STATE_MAY_INLINE_DATA);
+}
+
+static int ext4_finish_convert_inline_dir(handle_t *handle,
+					  struct inode *inode,
+					  struct buffer_head *dir_block,
+					  void *buf,
+					  int inline_size)
+{
+	int err, csum_size = 0, header_size = 0;
+	struct ext4_dir_entry_2 *de;
+	struct ext4_dir_entry_tail *t;
+	void *target = dir_block->b_data;
+
+	/*
+	 * First create "." and ".." and then copy the dir information
+	 * back to the block.
+	 */
+	de = (struct ext4_dir_entry_2 *)target;
+	de = ext4_init_dot_dotdot(inode, de,
+		inode->i_sb->s_blocksize, csum_size,
+		le32_to_cpu(((struct ext4_dir_entry_2 *)buf)->inode), 1);
+	header_size = (void *)de - target;
+
+	memcpy((void *)de, buf + EXT4_INLINE_DOTDOT_SIZE,
+		inline_size - EXT4_INLINE_DOTDOT_SIZE);
+
+	if (EXT4_HAS_RO_COMPAT_FEATURE(inode->i_sb,
+				       EXT4_FEATURE_RO_COMPAT_METADATA_CSUM))
+		csum_size = sizeof(struct ext4_dir_entry_tail);
+
+	inode->i_size = inode->i_sb->s_blocksize;
+	i_size_write(inode, inode->i_sb->s_blocksize);
+	EXT4_I(inode)->i_disksize = inode->i_sb->s_blocksize;
+	ext4_update_final_de(dir_block->b_data,
+			inline_size - EXT4_INLINE_DOTDOT_SIZE + header_size,
+			inode->i_sb->s_blocksize - csum_size);
+
+	if (csum_size) {
+		t = EXT4_DIRENT_TAIL(dir_block->b_data,
+				     inode->i_sb->s_blocksize);
+		initialize_dirent_tail(t, inode->i_sb->s_blocksize);
+	}
+	set_buffer_uptodate(dir_block);
+	err = ext4_handle_dirty_dirent_node(handle, inode, dir_block);
+	if (err)
+		goto out;
+	set_buffer_verified(dir_block);
+out:
+	return err;
+}
+
+static int ext4_convert_inline_data_nolock(handle_t *handle,
+					   struct inode *inode,
+					   struct ext4_iloc *iloc)
+{
+	int error;
+	void *buf = NULL;
+	struct buffer_head *data_bh = NULL;
+	struct ext4_map_blocks map;
+	int inline_size;
+
+	inline_size = ext4_get_inline_size(inode);
+	buf = kmalloc(inline_size, GFP_NOFS);
+	if (!buf) {
+		error = -ENOMEM;
+		goto out;
+	}
+
+	error = ext4_read_inline_data(inode, buf, inline_size, iloc);
+	if (error < 0)
+		goto out;
+
+	error = ext4_destroy_inline_data_nolock(handle, inode);
+	if (error)
+		goto out;
+
+	map.m_lblk = 0;
+	map.m_len = 1;
+	map.m_flags = 0;
+	error = ext4_map_blocks(handle, inode, &map, EXT4_GET_BLOCKS_CREATE);
+	if (error < 0)
+		goto out_restore;
+	if (!(map.m_flags & EXT4_MAP_MAPPED)) {
+		error = -EIO;
+		goto out_restore;
+	}
+
+	data_bh = sb_getblk(inode->i_sb, map.m_pblk);
+	if (!data_bh) {
+		error = -EIO;
+		goto out_restore;
+	}
+
+	lock_buffer(data_bh);
+	error = ext4_journal_get_create_access(handle, data_bh);
+	if (error) {
+		unlock_buffer(data_bh);
+		error = -EIO;
+		goto out_restore;
+	}
+	memset(data_bh->b_data, 0, inode->i_sb->s_blocksize);
+
+	if (!S_ISDIR(inode->i_mode)) {
+		memcpy(data_bh->b_data, buf, inline_size);
+		set_buffer_uptodate(data_bh);
+		error = ext4_handle_dirty_metadata(handle,
+						   inode, data_bh);
+	} else {
+		error = ext4_finish_convert_inline_dir(handle, inode, data_bh,
+						       buf, inline_size);
+	}
+
+	unlock_buffer(data_bh);
+out_restore:
+	if (error)
+		ext4_restore_inline_data(handle, inode, iloc, buf, inline_size);
+
+out:
+	brelse(data_bh);
+	kfree(buf);
+	return error;
+}
+
+/*
+ * Try to add the new entry to the inline data.
+ * If succeeds, return 0. If not, extended the inline dir and copied data to
+ * the new created block.
+ */
+int ext4_try_add_inline_entry(handle_t *handle, struct dentry *dentry,
+			      struct inode *inode)
+{
+	int ret, inline_size;
+	void *inline_start;
+	struct ext4_iloc iloc;
+	struct inode *dir = dentry->d_parent->d_inode;
+
+	ret = ext4_get_inode_loc(dir, &iloc);
+	if (ret)
+		return ret;
+
+	down_write(&EXT4_I(dir)->xattr_sem);
+	if (!ext4_has_inline_data(dir))
+		goto out;
+
+	inline_start = (void *)ext4_raw_inode(&iloc)->i_block +
+						 EXT4_INLINE_DOTDOT_SIZE;
+	inline_size = EXT4_MIN_INLINE_DATA_SIZE - EXT4_INLINE_DOTDOT_SIZE;
+
+	ret = ext4_add_dirent_to_inline(handle, dentry, inode, &iloc,
+					inline_start, inline_size);
+	if (ret != -ENOSPC)
+		goto out;
+
+	/* check whether it can be inserted to inline xattr space. */
+	inline_size = EXT4_I(dir)->i_inline_size -
+			EXT4_MIN_INLINE_DATA_SIZE;
+	if (!inline_size) {
+		/* Try to use the xattr space.*/
+		ret = ext4_update_inline_dir(handle, dir, &iloc);
+		if (ret && ret != -ENOSPC)
+			goto out;
+
+		inline_size = EXT4_I(dir)->i_inline_size -
+				EXT4_MIN_INLINE_DATA_SIZE;
+	}
+
+	if (inline_size) {
+		inline_start = ext4_get_inline_xattr_pos(dir, &iloc);
+
+		ret = ext4_add_dirent_to_inline(handle, dentry, inode, &iloc,
+						inline_start, inline_size);
+
+		if (ret != -ENOSPC)
+			goto out;
+	}
+
+	/*
+	 * The inline space is filled up, so create a new block for it.
+	 * As the extent tree will be created, we have to save the inline
+	 * dir first.
+	 */
+	ret = ext4_convert_inline_data_nolock(handle, dir, &iloc);
+
+out:
+	ext4_mark_inode_dirty(handle, dir);
+	up_write(&EXT4_I(dir)->xattr_sem);
+	brelse(iloc.bh);
+	return ret;
+}
+
+/*
+ * Try to create the inline data for the new dir.
+ * If it succeeds, return 0, otherwise return the error.
+ * In case of ENOSPC, the caller should create the normal disk layout dir.
+ */
+int ext4_try_create_inline_dir(handle_t *handle, struct inode *parent,
+			       struct inode *inode)
+{
+	int ret, inline_size = EXT4_MIN_INLINE_DATA_SIZE;
+	struct ext4_iloc iloc;
+	struct ext4_dir_entry_2 *de;
+
+	ret = ext4_get_inode_loc(inode, &iloc);
+	if (ret)
+		return ret;
+
+	ret = ext4_prepare_inline_data(handle, inode, inline_size);
+	if (ret)
+		goto out;
+
+	/*
+	 * For inline dir, we only save the inode information for the ".."
+	 * and create a fake dentry to cover the left space.
+	 */
+	de = (struct ext4_dir_entry_2 *)ext4_raw_inode(&iloc)->i_block;
+	de->inode = cpu_to_le32(parent->i_ino);
+	de = (struct ext4_dir_entry_2 *)((void *)de + EXT4_INLINE_DOTDOT_SIZE);
+	de->inode = 0;
+	de->rec_len = ext4_rec_len_to_disk(
+				inline_size - EXT4_INLINE_DOTDOT_SIZE,
+				inline_size);
+	set_nlink(inode, 2);
+	inode->i_size = EXT4_I(inode)->i_disksize = inline_size;
+out:
+	brelse(iloc.bh);
+	return ret;
+}
+
 int ext4_destroy_inline_data(handle_t *handle, struct inode *inode)
 {
 	int ret;