From ab2a29ccffd0e9fe62afb8bbd45e1709f9726942 Mon Sep 17 00:00:00 2001 From: Kent Overstreet Date: Tue, 2 Mar 2021 18:35:30 -0500 Subject: bcachefs: Inode backpointers This patch adds two new inode fields, bi_dir and bi_dir_offset, that point back to the inode's dirent. Since we're only adding fields for a single backpointer, files that have been hardlinked won't necessarily have valid backpointers: we also add a new inode flag, BCH_INODE_BACKPTR_UNTRUSTED, that's set if an inode has ever had multiple links to it. That's ok, because we only really need this functionality for directories, which can never have multiple hardlinks - when we add subvolumes, we'll need a way to enemurate and print subvolumes, and this will let us reconstruct a path to a subvolume root given a subvolume root inode. Signed-off-by: Kent Overstreet Signed-off-by: Kent Overstreet --- fs/bcachefs/fs-common.c | 68 ++++++++++++++++++++++++++++++++++++++----------- 1 file changed, 53 insertions(+), 15 deletions(-) (limited to 'fs/bcachefs/fs-common.c') diff --git a/fs/bcachefs/fs-common.c b/fs/bcachefs/fs-common.c index 503ce1920f39..83c2168ce480 100644 --- a/fs/bcachefs/fs-common.c +++ b/fs/bcachefs/fs-common.c @@ -20,8 +20,10 @@ int bch2_create_trans(struct btree_trans *trans, u64 dir_inum, { struct bch_fs *c = trans->c; struct btree_iter *dir_iter = NULL; + struct btree_iter *inode_iter = NULL; struct bch_hash_info hash = bch2_hash_info_init(c, new_inode); - u64 now = bch2_current_time(trans->c); + u64 now = bch2_current_time(c); + u64 dir_offset = 0; int ret; dir_iter = bch2_inode_peek(trans, dir_u, dir_inum, BTREE_ITER_INTENT); @@ -34,7 +36,8 @@ int bch2_create_trans(struct btree_trans *trans, u64 dir_inum, if (!name) new_inode->bi_flags |= BCH_INODE_UNLINKED; - ret = bch2_inode_create(trans, new_inode); + inode_iter = bch2_inode_create(trans, new_inode); + ret = PTR_ERR_OR_ZERO(inode_iter); if (ret) goto err; @@ -66,11 +69,20 @@ int bch2_create_trans(struct btree_trans *trans, u64 dir_inum, ret = bch2_dirent_create(trans, dir_inum, &dir_hash, mode_to_type(new_inode->bi_mode), name, new_inode->bi_inum, + &dir_offset, BCH_HASH_SET_MUST_CREATE); if (ret) goto err; } + + if (c->sb.version >= bcachefs_metadata_version_inode_backpointers) { + new_inode->bi_dir = dir_u->bi_inum; + new_inode->bi_dir_offset = dir_offset; + } + + ret = bch2_inode_write(trans, inode_iter, new_inode); err: + bch2_trans_iter_put(trans, inode_iter); bch2_trans_iter_put(trans, dir_iter); return ret; } @@ -79,9 +91,11 @@ int bch2_link_trans(struct btree_trans *trans, u64 dir_inum, u64 inum, struct bch_inode_unpacked *dir_u, struct bch_inode_unpacked *inode_u, const struct qstr *name) { + struct bch_fs *c = trans->c; struct btree_iter *dir_iter = NULL, *inode_iter = NULL; struct bch_hash_info dir_hash; - u64 now = bch2_current_time(trans->c); + u64 now = bch2_current_time(c); + u64 dir_offset = 0; int ret; inode_iter = bch2_inode_peek(trans, inode_u, inum, BTREE_ITER_INTENT); @@ -92,6 +106,8 @@ int bch2_link_trans(struct btree_trans *trans, u64 dir_inum, inode_u->bi_ctime = now; bch2_inode_nlink_inc(inode_u); + inode_u->bi_flags |= BCH_INODE_BACKPTR_UNTRUSTED; + dir_iter = bch2_inode_peek(trans, dir_u, dir_inum, 0); ret = PTR_ERR_OR_ZERO(dir_iter); if (ret) @@ -99,12 +115,21 @@ int bch2_link_trans(struct btree_trans *trans, u64 dir_inum, dir_u->bi_mtime = dir_u->bi_ctime = now; - dir_hash = bch2_hash_info_init(trans->c, dir_u); + dir_hash = bch2_hash_info_init(c, dir_u); - ret = bch2_dirent_create(trans, dir_inum, &dir_hash, - mode_to_type(inode_u->bi_mode), - name, inum, BCH_HASH_SET_MUST_CREATE) ?: - bch2_inode_write(trans, dir_iter, dir_u) ?: + ret = bch2_dirent_create(trans, dir_inum, &dir_hash, + mode_to_type(inode_u->bi_mode), + name, inum, &dir_offset, + BCH_HASH_SET_MUST_CREATE); + if (ret) + goto err; + + if (c->sb.version >= bcachefs_metadata_version_inode_backpointers) { + inode_u->bi_dir = dir_inum; + inode_u->bi_dir_offset = dir_offset; + } + + ret = bch2_inode_write(trans, dir_iter, dir_u) ?: bch2_inode_write(trans, inode_iter, inode_u); err: bch2_trans_iter_put(trans, dir_iter); @@ -117,10 +142,11 @@ int bch2_unlink_trans(struct btree_trans *trans, struct bch_inode_unpacked *inode_u, const struct qstr *name) { + struct bch_fs *c = trans->c; struct btree_iter *dir_iter = NULL, *dirent_iter = NULL, *inode_iter = NULL; struct bch_hash_info dir_hash; - u64 inum, now = bch2_current_time(trans->c); + u64 inum, now = bch2_current_time(c); struct bkey_s_c k; int ret; @@ -129,7 +155,7 @@ int bch2_unlink_trans(struct btree_trans *trans, if (ret) goto err; - dir_hash = bch2_hash_info_init(trans->c, dir_u); + dir_hash = bch2_hash_info_init(c, dir_u); dirent_iter = __bch2_dirent_lookup_trans(trans, dir_inum, &dir_hash, name, BTREE_ITER_INTENT); @@ -195,10 +221,12 @@ int bch2_rename_trans(struct btree_trans *trans, const struct qstr *dst_name, enum bch_rename_mode mode) { + struct bch_fs *c = trans->c; struct btree_iter *src_dir_iter = NULL, *dst_dir_iter = NULL; struct btree_iter *src_inode_iter = NULL, *dst_inode_iter = NULL; struct bch_hash_info src_hash, dst_hash; - u64 src_inode, dst_inode, now = bch2_current_time(trans->c); + u64 src_inode, src_offset, dst_inode, dst_offset; + u64 now = bch2_current_time(c); int ret; src_dir_iter = bch2_inode_peek(trans, src_dir_u, src_dir, @@ -207,7 +235,7 @@ int bch2_rename_trans(struct btree_trans *trans, if (ret) goto err; - src_hash = bch2_hash_info_init(trans->c, src_dir_u); + src_hash = bch2_hash_info_init(c, src_dir_u); if (dst_dir != src_dir) { dst_dir_iter = bch2_inode_peek(trans, dst_dir_u, dst_dir, @@ -216,7 +244,7 @@ int bch2_rename_trans(struct btree_trans *trans, if (ret) goto err; - dst_hash = bch2_hash_info_init(trans->c, dst_dir_u); + dst_hash = bch2_hash_info_init(c, dst_dir_u); } else { dst_dir_u = src_dir_u; dst_hash = src_hash; @@ -225,8 +253,8 @@ int bch2_rename_trans(struct btree_trans *trans, ret = bch2_dirent_rename(trans, src_dir, &src_hash, dst_dir, &dst_hash, - src_name, &src_inode, - dst_name, &dst_inode, + src_name, &src_inode, &src_offset, + dst_name, &dst_inode, &dst_offset, mode); if (ret) goto err; @@ -245,6 +273,16 @@ int bch2_rename_trans(struct btree_trans *trans, goto err; } + if (c->sb.version >= bcachefs_metadata_version_inode_backpointers) { + src_inode_u->bi_dir = dst_dir_u->bi_inum; + src_inode_u->bi_dir_offset = dst_offset; + + if (mode == BCH_RENAME_EXCHANGE) { + dst_inode_u->bi_dir = src_dir_u->bi_inum; + dst_inode_u->bi_dir_offset = src_offset; + } + } + if (mode == BCH_RENAME_OVERWRITE) { if (S_ISDIR(src_inode_u->bi_mode) != S_ISDIR(dst_inode_u->bi_mode)) { -- cgit v1.2.3