From 8d45dc270a3791d7217625190c9fc8f7cc129285 Mon Sep 17 00:00:00 2001 From: Qu Wenruo Date: Tue, 31 Dec 2019 15:12:17 +0800 Subject: [PATCH] btrfs-progs: check: Populate extent generation correctly for data extents [BUG] When using `btrfs check --init-extent-tree`, we will create incorrect generation number for data extents in extent tree: item 10 key (13631488 EXTENT_ITEM 1048576) itemoff 15828 itemsize 53 refs 1 gen 0 flags DATA extent data backref root FS_TREE objectid 257 offset 0 count 1 [CAUSE] Since data extent generation is not as obvious as tree blocks, which has header containing its generations, so for data extents, its extent_record::generation is not really updated, resulting such 0 generation. [FIX] To get generation of a data extent, there are two sources we can rely: - EXTENT_ITEM There is always a btrfs_extent_item::generation can be utilized. Although this is not possible for --init-extent-tree use case. - EXTENT_DATA We have btrfs_file_extent_item::generation for regular and preallocated data extents. Since --init-extent-tree will go through subvolume trees, this would be the main source for extent data generation. Then we only need to make add_data_backref() to accept @gen parameter, and pass it down to extent_record structure. And for the final extent item generation update, here we add extra fallback values, if we can't find FILE_EXTENT items. In that case, we just fall back to current transid. With this modification, recreated data EXTENT_ITEM now has correct generation number: item 10 key (13631488 EXTENT_ITEM 1048576) itemoff 15828 itemsize 53 refs 1 gen 6 flags DATA extent data backref root FS_TREE objectid 257 offset 0 count 1 Reviewed-by: Su Yue Signed-off-by: Qu Wenruo Signed-off-by: David Sterba --- check/main.c | 24 +++++++++++++++++------- 1 file changed, 17 insertions(+), 7 deletions(-) diff --git a/check/main.c b/check/main.c index 1537ed3e..86809b49 100644 --- a/check/main.c +++ b/check/main.c @@ -4810,7 +4810,7 @@ static int add_tree_backref(struct cache_tree *extent_cache, u64 bytenr, static int add_data_backref(struct cache_tree *extent_cache, u64 bytenr, u64 parent, u64 root, u64 owner, u64 offset, - u32 num_refs, int found_ref, u64 max_size) + u32 num_refs, u64 gen, int found_ref, u64 max_size) { struct extent_record *rec; struct data_backref *back; @@ -4826,6 +4826,7 @@ static int add_data_backref(struct cache_tree *extent_cache, u64 bytenr, tmpl.start = bytenr; tmpl.nr = 1; tmpl.max_size = max_size; + tmpl.generation = gen; ret = add_extent_rec_nolookup(extent_cache, &tmpl); if (ret) @@ -4840,6 +4841,8 @@ static int add_data_backref(struct cache_tree *extent_cache, u64 bytenr, if (rec->max_size < max_size) rec->max_size = max_size; + if (rec->generation < gen) + rec->generation = gen; /* * If found_ref is set then max_size is the real size and must match the * existing refs. So if we have already found a ref then we need to @@ -5315,6 +5318,7 @@ static int process_extent_item(struct btrfs_root *root, u64 refs = 0; u64 offset; u64 num_bytes; + u64 gen; int metadata = 0; btrfs_item_key_to_cpu(eb, &key, slot); @@ -5340,6 +5344,7 @@ static int process_extent_item(struct btrfs_root *root, ei = btrfs_item_ptr(eb, slot, struct btrfs_extent_item); refs = btrfs_extent_refs(eb, ei); + gen = btrfs_extent_generation(eb, ei); if (btrfs_extent_flags(eb, ei) & BTRFS_EXTENT_FLAG_TREE_BLOCK) metadata = 1; else @@ -5362,6 +5367,7 @@ static int process_extent_item(struct btrfs_root *root, tmpl.metadata = metadata; tmpl.found_rec = 1; tmpl.max_size = num_bytes; + tmpl.generation = gen; add_extent_rec(extent_cache, &tmpl); ptr = (unsigned long)(ei + 1); @@ -5401,14 +5407,14 @@ static int process_extent_item(struct btrfs_root *root, dref), btrfs_extent_data_ref_offset(eb, dref), btrfs_extent_data_ref_count(eb, dref), - 0, num_bytes); + gen, 0, num_bytes); break; case BTRFS_SHARED_DATA_REF_KEY: sref = (struct btrfs_shared_data_ref *)(iref + 1); add_data_backref(extent_cache, key.objectid, offset, 0, 0, 0, btrfs_shared_data_ref_count(eb, sref), - 0, num_bytes); + gen, 0, num_bytes); break; default: fprintf(stderr, @@ -6355,7 +6361,7 @@ static int run_next_block(struct btrfs_root *root, ref), btrfs_extent_data_ref_offset(buf, ref), btrfs_extent_data_ref_count(buf, ref), - 0, root->fs_info->sectorsize); + 0, 0, root->fs_info->sectorsize); continue; } if (key.type == BTRFS_SHARED_DATA_REF_KEY) { @@ -6366,7 +6372,7 @@ static int run_next_block(struct btrfs_root *root, add_data_backref(extent_cache, key.objectid, key.offset, 0, 0, 0, btrfs_shared_data_ref_count(buf, ref), - 0, root->fs_info->sectorsize); + 0, 0, root->fs_info->sectorsize); continue; } if (key.type == BTRFS_ORPHAN_ITEM_KEY) { @@ -6433,7 +6439,8 @@ static int run_next_block(struct btrfs_root *root, add_data_backref(extent_cache, btrfs_file_extent_disk_bytenr(buf, fi), parent, owner, key.objectid, key.offset - - btrfs_file_extent_offset(buf, fi), 1, 1, + btrfs_file_extent_offset(buf, fi), 1, + btrfs_file_extent_generation(buf, fi), 1, btrfs_file_extent_disk_num_bytes(buf, fi)); } } else { @@ -6736,7 +6743,10 @@ static int record_extent(struct btrfs_trans_handle *trans, struct btrfs_extent_item); btrfs_set_extent_refs(leaf, ei, 0); - btrfs_set_extent_generation(leaf, ei, rec->generation); + if (rec->generation) + btrfs_set_extent_generation(leaf, ei, rec->generation); + else + btrfs_set_extent_generation(leaf, ei, trans->transid); if (back->is_data) { btrfs_set_extent_flags(leaf, ei,