Commit f232ab04 authored May 14, 2019 by Nikolay Borisov Committed by David Sterba Jul 01, 2019

btrfs: Explicitly reserve space for devreplace item



Part of device replace involves writing an item to the device root
containing information about pending replace operations. Currently space
for this item is not being explicitly reserved so this works thanks to
presence of global reserve. While not fatal it's not a good practice.
Let's be explicit about space requirement of device replace and reserve
space when starting the transaction.

Reviewed-by: Johannes Thumshirn <jthumshirn@suse.de>
Signed-off-by: Nikolay Borisov <nborisov@suse.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>

parent fa19452a

fs/btrfs/dev-replace.c

+2 −2

Original line number	Diff line number	Diff line
		@@ -477,8 +477,8 @@ static int btrfs_dev_replace_start(struct btrfs_fs_info *fs_info,

		btrfs_wait_ordered_roots(fs_info, U64_MAX, 0, (u64)-1);

		/* force writing the updated state information to disk */
		trans = btrfs_start_transaction(root, 0);
		/* Commit dev_replace state and reserve 1 item for it. */
		trans = btrfs_start_transaction(root, 1);
		if (IS_ERR(trans)) {
		ret = PTR_ERR(trans);
		down_write(&dev_replace->rwsem);

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