btrfs: add cancellation points to defrag (210549eb) · Commits · 戴 / test

The defrag operation can take very long, we want to have a way how to cancel it. The code checks for a pending signal at safe points in the defrag loops and returns EAGAIN. This means a user can press ^C after running 'btrfs fi defrag', woks for both defrag modes, files and root. Returning from the command was instant in my light tests, but may take longer depending on the aging factor of the filesystem. Signed-off-by:

David Sterba <dsterba@suse.cz> Signed-off-by:

Josef Bacik <jbacik@fusionio.com>

fs/btrfs/ctree.h

+7 −0

Original line number	Diff line number	Diff line
		@@ -3786,4 +3786,11 @@ static inline int is_fstree(u64 rootid)
		return 1;
		return 0;
		}

		static inline int btrfs_defrag_cancelled(struct btrfs_fs_info *fs_info)
		{
		return signal_pending(current);
		}


		#endif

fs/btrfs/ioctl.c

+6 −0

Original line number	Diff line number	Diff line
		@@ -1202,6 +1202,12 @@ int btrfs_defrag_file(struct inode inode, struct file file,
		if (!(inode->i_sb->s_flags & MS_ACTIVE))
		break;

		if (btrfs_defrag_cancelled(root->fs_info)) {
		printk(KERN_DEBUG "btrfs: defrag_file cancelled\n");
		ret = -EAGAIN;
		break;
		}

		if (!should_defrag_range(inode, (u64)i << PAGE_CACHE_SHIFT,
		extent_thresh, &last_len, &skip,
		&defrag_end, range->flags &

fs/btrfs/transaction.c

+6 −0

Original line number	Diff line number	Diff line
		@@ -984,6 +984,12 @@ int btrfs_defrag_root(struct btrfs_root *root)

		if (btrfs_fs_closing(root->fs_info) \|\| ret != -EAGAIN)
		break;

		if (btrfs_defrag_cancelled(root->fs_info)) {
		printk(KERN_DEBUG "btrfs: defrag_root cancelled\n");
		ret = -EAGAIN;
		break;
		}
		}
		root->defrag_running = 0;
		return ret;

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