Commit d38c3fa6 authored by Linus Torvalds's avatar Linus Torvalds
Browse files

Merge tag 'for-5.3-rc2-tag' of git://git.kernel.org/pub/scm/linux/kernel/git/kdave/linux 

Pull btrfs fixes from David Sterba:

 - tiny race window during 2 transactions aborting at the same time can
   accidentally lead to a commit

 - regression fix, possible deadlock during fiemap

 - fix for an old bug when incremental send can fail on a file that has
   been deduplicated in a special way

* tag 'for-5.3-rc2-tag' of git://git.kernel.org/pub/scm/linux/kernel/git/kdave/linux:
  Btrfs: fix deadlock between fiemap and transaction commits
  Btrfs: fix race leading to fs corruption after transaction abort
  Btrfs: fix incremental send failure after deduplication
parents 97b00aff a6d155d2

fs/btrfs/backref.c

+1 −1
Original line number Diff line number Diff line
@@ -1483,7 +1483,7 @@ int btrfs_check_shared(struct btrfs_root *root, u64 inum, u64 bytenr, 
	ulist_init(roots);

	ulist_init(tmp);



	trans = btrfs_attach_transaction(root);

	trans = btrfs_join_transaction_nostart(root);

	if (IS_ERR(trans)) {

		if (PTR_ERR(trans) != -ENOENT && PTR_ERR(trans) != -EROFS) {

			ret = PTR_ERR(trans);

fs/btrfs/send.c

+15 −62
Original line number Diff line number Diff line
@@ -6322,68 +6322,21 @@ static int changed_extent(struct send_ctx *sctx, 
{

	int ret = 0;



	if (sctx->cur_ino != sctx->cmp_key->objectid) {



		if (result == BTRFS_COMPARE_TREE_CHANGED) {

			struct extent_buffer *leaf_l;

			struct extent_buffer *leaf_r;

			struct btrfs_file_extent_item *ei_l;

			struct btrfs_file_extent_item *ei_r;



			leaf_l = sctx->left_path->nodes[0];

			leaf_r = sctx->right_path->nodes[0];

			ei_l = btrfs_item_ptr(leaf_l,

					      sctx->left_path->slots[0],

					      struct btrfs_file_extent_item);

			ei_r = btrfs_item_ptr(leaf_r,

					      sctx->right_path->slots[0],

					      struct btrfs_file_extent_item);



	/*

			 * We may have found an extent item that has changed

			 * only its disk_bytenr field and the corresponding

			 * inode item was not updated. This case happens due to

			 * very specific timings during relocation when a leaf

			 * that contains file extent items is COWed while

			 * relocation is ongoing and its in the stage where it

			 * updates data pointers. So when this happens we can

			 * safely ignore it since we know it's the same extent,

			 * but just at different logical and physical locations

			 * (when an extent is fully replaced with a new one, we

			 * know the generation number must have changed too,

			 * since snapshot creation implies committing the current

			 * transaction, and the inode item must have been updated

			 * as well).

			 * This replacement of the disk_bytenr happens at

			 * relocation.c:replace_file_extents() through

			 * relocation.c:btrfs_reloc_cow_block().

			 */

			if (btrfs_file_extent_generation(leaf_l, ei_l) ==

			    btrfs_file_extent_generation(leaf_r, ei_r) &&

			    btrfs_file_extent_ram_bytes(leaf_l, ei_l) ==

			    btrfs_file_extent_ram_bytes(leaf_r, ei_r) &&

			    btrfs_file_extent_compression(leaf_l, ei_l) ==

			    btrfs_file_extent_compression(leaf_r, ei_r) &&

			    btrfs_file_extent_encryption(leaf_l, ei_l) ==

			    btrfs_file_extent_encryption(leaf_r, ei_r) &&

			    btrfs_file_extent_other_encoding(leaf_l, ei_l) ==

			    btrfs_file_extent_other_encoding(leaf_r, ei_r) &&

			    btrfs_file_extent_type(leaf_l, ei_l) ==

			    btrfs_file_extent_type(leaf_r, ei_r) &&

			    btrfs_file_extent_disk_bytenr(leaf_l, ei_l) !=

			    btrfs_file_extent_disk_bytenr(leaf_r, ei_r) &&

			    btrfs_file_extent_disk_num_bytes(leaf_l, ei_l) ==

			    btrfs_file_extent_disk_num_bytes(leaf_r, ei_r) &&

			    btrfs_file_extent_offset(leaf_l, ei_l) ==

			    btrfs_file_extent_offset(leaf_r, ei_r) &&

			    btrfs_file_extent_num_bytes(leaf_l, ei_l) ==

			    btrfs_file_extent_num_bytes(leaf_r, ei_r))

	 * We have found an extent item that changed without the inode item

	 * having changed. This can happen either after relocation (where the

	 * disk_bytenr of an extent item is replaced at

	 * relocation.c:replace_file_extents()) or after deduplication into a

	 * file in both the parent and send snapshots (where an extent item can

	 * get modified or replaced with a new one). Note that deduplication

	 * updates the inode item, but it only changes the iversion (sequence

	 * field in the inode item) of the inode, so if a file is deduplicated

	 * the same amount of times in both the parent and send snapshots, its

	 * iversion becames the same in both snapshots, whence the inode item is

	 * the same on both snapshots.

	 */

	if (sctx->cur_ino != sctx->cmp_key->objectid)

		return 0;

		}



		inconsistent_snapshot_error(sctx, result, "extent");

		return -EIO;

	}



	if (!sctx->cur_inode_new_gen && !sctx->cur_inode_deleted) {

		if (result != BTRFS_COMPARE_TREE_DELETED)

fs/btrfs/transaction.c

+28 −4
Original line number Diff line number Diff line
@@ -28,15 +28,18 @@ static const unsigned int btrfs_blocked_trans_types[TRANS_STATE_MAX] = { 
	[TRANS_STATE_COMMIT_START]	= (__TRANS_START | __TRANS_ATTACH),

	[TRANS_STATE_COMMIT_DOING]	= (__TRANS_START |

					   __TRANS_ATTACH |

					   __TRANS_JOIN),

					   __TRANS_JOIN |

					   __TRANS_JOIN_NOSTART),

	[TRANS_STATE_UNBLOCKED]		= (__TRANS_START |

					   __TRANS_ATTACH |

					   __TRANS_JOIN |

					   __TRANS_JOIN_NOLOCK),

					   __TRANS_JOIN_NOLOCK |

					   __TRANS_JOIN_NOSTART),

	[TRANS_STATE_COMPLETED]		= (__TRANS_START |

					   __TRANS_ATTACH |

					   __TRANS_JOIN |

					   __TRANS_JOIN_NOLOCK),

					   __TRANS_JOIN_NOLOCK |

					   __TRANS_JOIN_NOSTART),

};



void btrfs_put_transaction(struct btrfs_transaction *transaction)
@@ -543,7 +546,8 @@ start_transaction(struct btrfs_root *root, unsigned int num_items, 
		ret = join_transaction(fs_info, type);

		if (ret == -EBUSY) {

			wait_current_trans(fs_info);

			if (unlikely(type == TRANS_ATTACH))

			if (unlikely(type == TRANS_ATTACH ||

				     type == TRANS_JOIN_NOSTART))

				ret = -ENOENT;

		}

	} while (ret == -EBUSY);
@@ -659,6 +663,16 @@ struct btrfs_trans_handle *btrfs_join_transaction_nolock(struct btrfs_root *root 
				 BTRFS_RESERVE_NO_FLUSH, true);

}



/*

 * Similar to regular join but it never starts a transaction when none is

 * running or after waiting for the current one to finish.

 */

struct btrfs_trans_handle *btrfs_join_transaction_nostart(struct btrfs_root *root)

{

	return start_transaction(root, 0, TRANS_JOIN_NOSTART,

				 BTRFS_RESERVE_NO_FLUSH, true);

}



/*

 * btrfs_attach_transaction() - catch the running transaction

 *
@@ -2037,6 +2051,16 @@ int btrfs_commit_transaction(struct btrfs_trans_handle *trans) 
		}

	} else {

		spin_unlock(&fs_info->trans_lock);

		/*

		 * The previous transaction was aborted and was already removed

		 * from the list of transactions at fs_info->trans_list. So we

		 * abort to prevent writing a new superblock that reflects a

		 * corrupt state (pointing to trees with unwritten nodes/leafs).

		 */

		if (test_bit(BTRFS_FS_STATE_TRANS_ABORTED, &fs_info->fs_state)) {

			ret = -EROFS;

			goto cleanup_transaction;

		}

	}



	extwriter_counter_dec(cur_trans, trans->type);

fs/btrfs/transaction.h

+3 −0
Original line number Diff line number Diff line
@@ -94,11 +94,13 @@ struct btrfs_transaction { 
#define __TRANS_JOIN		(1U << 11)

#define __TRANS_JOIN_NOLOCK	(1U << 12)

#define __TRANS_DUMMY		(1U << 13)

#define __TRANS_JOIN_NOSTART	(1U << 14)



#define TRANS_START		(__TRANS_START | __TRANS_FREEZABLE)

#define TRANS_ATTACH		(__TRANS_ATTACH)

#define TRANS_JOIN		(__TRANS_JOIN | __TRANS_FREEZABLE)

#define TRANS_JOIN_NOLOCK	(__TRANS_JOIN_NOLOCK)

#define TRANS_JOIN_NOSTART	(__TRANS_JOIN_NOSTART)



#define TRANS_EXTWRITERS	(__TRANS_START | __TRANS_ATTACH)
@@ -183,6 +185,7 @@ struct btrfs_trans_handle *btrfs_start_transaction_fallback_global_rsv( 
					int min_factor);

struct btrfs_trans_handle *btrfs_join_transaction(struct btrfs_root *root);

struct btrfs_trans_handle *btrfs_join_transaction_nolock(struct btrfs_root *root);

struct btrfs_trans_handle *btrfs_join_transaction_nostart(struct btrfs_root *root);

struct btrfs_trans_handle *btrfs_attach_transaction(struct btrfs_root *root);

struct btrfs_trans_handle *btrfs_attach_transaction_barrier(

					struct btrfs_root *root);