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Commit cd808dec authored by Miklos Szeredi's avatar Miklos Szeredi
Browse files

ext4: support RENAME_WHITEOUT 



Add whiteout support to ext4_rename().  A whiteout inode (chrdev/0,0) is
created before the rename takes place.  The whiteout inode is added to the
old entry instead of deleting it.

Signed-off-by: default avatarMiklos Szeredi <mszeredi@suse.cz>
parent 0d7a8555

fs/ext4/namei.c

+78 −17
Original line number Diff line number Diff line
@@ -3190,6 +3190,39 @@ static void ext4_update_dir_count(handle_t *handle, struct ext4_renament *ent) 
	}

}



static struct inode *ext4_whiteout_for_rename(struct ext4_renament *ent,

					      int credits, handle_t **h)

{

	struct inode *wh;

	handle_t *handle;

	int retries = 0;



	/*

	 * for inode block, sb block, group summaries,

	 * and inode bitmap

	 */

	credits += (EXT4_MAXQUOTAS_TRANS_BLOCKS(ent->dir->i_sb) +

		    EXT4_XATTR_TRANS_BLOCKS + 4);

retry:

	wh = ext4_new_inode_start_handle(ent->dir, S_IFCHR | WHITEOUT_MODE,

					 &ent->dentry->d_name, 0, NULL,

					 EXT4_HT_DIR, credits);



	handle = ext4_journal_current_handle();

	if (IS_ERR(wh)) {

		if (handle)

			ext4_journal_stop(handle);

		if (PTR_ERR(wh) == -ENOSPC &&

		    ext4_should_retry_alloc(ent->dir->i_sb, &retries))

			goto retry;

	} else {

		*h = handle;

		init_special_inode(wh, wh->i_mode, WHITEOUT_DEV);

		wh->i_op = &ext4_special_inode_operations;

	}

	return wh;

}



/*

 * Anybody can rename anything with this: the permission checks are left to the

 * higher-level routines.
@@ -3199,7 +3232,8 @@ static void ext4_update_dir_count(handle_t *handle, struct ext4_renament *ent) 
 * This comes from rename(const char *oldpath, const char *newpath)

 */

static int ext4_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)

{

	handle_t *handle = NULL;

	struct ext4_renament old = {
@@ -3214,6 +3248,9 @@ static int ext4_rename(struct inode *old_dir, struct dentry *old_dentry, 
	};

	int force_reread;

	int retval;

	struct inode *whiteout = NULL;

	int credits;

	u8 old_file_type;



	dquot_initialize(old.dir);

	dquot_initialize(new.dir);
@@ -3252,11 +3289,17 @@ static int ext4_rename(struct inode *old_dir, struct dentry *old_dentry, 
	if (new.inode && !test_opt(new.dir->i_sb, NO_AUTO_DA_ALLOC))

		ext4_alloc_da_blocks(old.inode);



	handle = ext4_journal_start(old.dir, EXT4_HT_DIR,

		(2 * EXT4_DATA_TRANS_BLOCKS(old.dir->i_sb) +

		 EXT4_INDEX_EXTRA_TRANS_BLOCKS + 2));

	credits = (2 * EXT4_DATA_TRANS_BLOCKS(old.dir->i_sb) +

		   EXT4_INDEX_EXTRA_TRANS_BLOCKS + 2);

	if (!(flags & RENAME_WHITEOUT)) {

		handle = ext4_journal_start(old.dir, EXT4_HT_DIR, credits);

		if (IS_ERR(handle))

			return PTR_ERR(handle);

	} else {

		whiteout = ext4_whiteout_for_rename(&old, credits, &handle);

		if (IS_ERR(whiteout))

			return PTR_ERR(whiteout);

	}



	if (IS_DIRSYNC(old.dir) || IS_DIRSYNC(new.dir))

		ext4_handle_sync(handle);
@@ -3284,13 +3327,26 @@ static int ext4_rename(struct inode *old_dir, struct dentry *old_dentry, 
	 */

	force_reread = (new.dir->i_ino == old.dir->i_ino &&

			ext4_test_inode_flag(new.dir, EXT4_INODE_INLINE_DATA));



	old_file_type = old.de->file_type;

	if (whiteout) {

		/*

		 * Do this before adding a new entry, so the old entry is sure

		 * to be still pointing to the valid old entry.

		 */

		retval = ext4_setent(handle, &old, whiteout->i_ino,

				     EXT4_FT_CHRDEV);

		if (retval)

			goto end_rename;

		ext4_mark_inode_dirty(handle, whiteout);

	}

	if (!new.bh) {

		retval = ext4_add_entry(handle, new.dentry, old.inode);

		if (retval)

			goto end_rename;

	} else {

		retval = ext4_setent(handle, &new,

				     old.inode->i_ino, old.de->file_type);

				     old.inode->i_ino, old_file_type);

		if (retval)

			goto end_rename;

	}
@@ -3305,10 +3361,12 @@ static int ext4_rename(struct inode *old_dir, struct dentry *old_dentry, 
	old.inode->i_ctime = ext4_current_time(old.inode);

	ext4_mark_inode_dirty(handle, old.inode);



	if (!whiteout) {

		/*

		 * ok, that's it

		 */

		ext4_rename_delete(handle, &old, force_reread);

	}



	if (new.inode) {

		ext4_dec_count(handle, new.inode);
@@ -3344,6 +3402,12 @@ static int ext4_rename(struct inode *old_dir, struct dentry *old_dentry, 
	brelse(old.dir_bh);

	brelse(old.bh);

	brelse(new.bh);

	if (whiteout) {

		if (retval)

			drop_nlink(whiteout);

		unlock_new_inode(whiteout);

		iput(whiteout);

	}

	if (handle)

		ext4_journal_stop(handle);

	return retval;
@@ -3476,18 +3540,15 @@ static int ext4_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_EXCHANGE))

	if (flags & ~(RENAME_NOREPLACE | RENAME_EXCHANGE | RENAME_WHITEOUT))

		return -EINVAL;



	if (flags & RENAME_EXCHANGE) {

		return ext4_cross_rename(old_dir, old_dentry,

					 new_dir, new_dentry);

	}

	/*

	 * Existence checking was done by the VFS, otherwise "RENAME_NOREPLACE"

	 * is equivalent to regular rename.

	 */

	return ext4_rename(old_dir, old_dentry, new_dir, new_dentry);



	return ext4_rename(old_dir, old_dentry, new_dir, new_dentry, flags);

}



/*