Commit b2b5ef5c authored by Jan Kara's avatar Jan Kara Committed by Al Viro
Browse files

btrfs: Convert to new freezing mechanism 



We convert btrfs_file_aio_write() to use new freeze check.  We also add proper
freeze protection to btrfs_page_mkwrite(). We also add freeze protection to
the transaction mechanism to avoid starting transactions on frozen filesystem.
At minimum this is necessary to stop iput() of unlinked file to change frozen
filesystem during truncation.

Checks in cleaner_kthread() and transaction_kthread() can be safely removed
since btrfs_freeze() will lock the mutexes and thus block the threads (and they
shouldn't have anything to do anyway).

CC: linux-btrfs@vger.kernel.org
CC: Chris Mason <chris.mason@oracle.com>
Signed-off-by: default avatarJan Kara <jack@suse.cz>
Signed-off-by: default avatarAl Viro <viro@zeniv.linux.org.uk>
parent 2c22b337

fs/btrfs/disk-io.c

+0 −3
Original line number Diff line number Diff line
@@ -1533,8 +1533,6 @@ static int cleaner_kthread(void *arg) 
	struct btrfs_root *root = arg;



	do {

		vfs_check_frozen(root->fs_info->sb, SB_FREEZE_WRITE);



		if (!(root->fs_info->sb->s_flags & MS_RDONLY) &&

		    mutex_trylock(&root->fs_info->cleaner_mutex)) {

			btrfs_run_delayed_iputs(root);
@@ -1566,7 +1564,6 @@ static int transaction_kthread(void *arg) 
	do {

		cannot_commit = false;

		delay = HZ * 30;

		vfs_check_frozen(root->fs_info->sb, SB_FREEZE_WRITE);

		mutex_lock(&root->fs_info->transaction_kthread_mutex);



		spin_lock(&root->fs_info->trans_lock);

fs/btrfs/file.c

+2 −1
Original line number Diff line number Diff line
@@ -1379,7 +1379,7 @@ static ssize_t btrfs_file_aio_write(struct kiocb *iocb, 
	ssize_t err = 0;

	size_t count, ocount;



	vfs_check_frozen(inode->i_sb, SB_FREEZE_WRITE);

	sb_start_write(inode->i_sb);



	mutex_lock(&inode->i_mutex);
@@ -1469,6 +1469,7 @@ static ssize_t btrfs_file_aio_write(struct kiocb *iocb, 
			num_written = err;

	}

out:

	sb_end_write(inode->i_sb);

	current->backing_dev_info = NULL;

	return num_written ? num_written : err;

}

fs/btrfs/inode.c

+5 −1
Original line number Diff line number Diff line
@@ -6620,6 +6620,7 @@ int btrfs_page_mkwrite(struct vm_area_struct *vma, struct vm_fault *vmf) 
	u64 page_start;

	u64 page_end;



	sb_start_pagefault(inode->i_sb);

	ret  = btrfs_delalloc_reserve_space(inode, PAGE_CACHE_SIZE);

	if (!ret) {

		ret = file_update_time(vma->vm_file);
@@ -6709,12 +6710,15 @@ again: 
	unlock_extent_cached(io_tree, page_start, page_end, &cached_state, GFP_NOFS);



out_unlock:

	if (!ret)

	if (!ret) {

		sb_end_pagefault(inode->i_sb);

		return VM_FAULT_LOCKED;

	}

	unlock_page(page);

out:

	btrfs_delalloc_release_space(inode, PAGE_CACHE_SIZE);

out_noreserve:

	sb_end_pagefault(inode->i_sb);

	return ret;

}

fs/btrfs/transaction.c

+7 −0
Original line number Diff line number Diff line
@@ -329,6 +329,8 @@ again: 
	if (!h)

		return ERR_PTR(-ENOMEM);



	sb_start_intwrite(root->fs_info->sb);



	if (may_wait_transaction(root, type))

		wait_current_trans(root);
@@ -339,6 +341,7 @@ again: 
	} while (ret == -EBUSY);



	if (ret < 0) {

		sb_end_intwrite(root->fs_info->sb);

		kmem_cache_free(btrfs_trans_handle_cachep, h);

		return ERR_PTR(ret);

	}
@@ -528,6 +531,8 @@ static int __btrfs_end_transaction(struct btrfs_trans_handle *trans, 
		count++;

	}



	sb_end_intwrite(root->fs_info->sb);



	if (lock && !atomic_read(&root->fs_info->open_ioctl_trans) &&

	    should_end_transaction(trans, root)) {

		trans->transaction->blocked = 1;
@@ -1517,6 +1522,8 @@ int btrfs_commit_transaction(struct btrfs_trans_handle *trans, 
	put_transaction(cur_trans);

	put_transaction(cur_trans);



	sb_end_intwrite(root->fs_info->sb);



	trace_btrfs_transaction_commit(root);



	btrfs_scrub_continue(root);

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