1 files changed, 580 insertions, 0 deletions

diff --git a/fs/bcachefs/dirent.c b/fs/bcachefs/dirent.c
new file mode 100644
index 0000000000..2bfff0da70
--- /dev/null
+++ b/fs/bcachefs/dirent.c
@@ -0,0 +1,580 @@
+// SPDX-License-Identifier: GPL-2.0
+
+#include "bcachefs.h"
+#include "bkey_buf.h"
+#include "bkey_methods.h"
+#include "btree_update.h"
+#include "extents.h"
+#include "dirent.h"
+#include "fs.h"
+#include "keylist.h"
+#include "str_hash.h"
+#include "subvolume.h"
+
+#include <linux/dcache.h>
+
+static unsigned bch2_dirent_name_bytes(struct bkey_s_c_dirent d)
+{
+	unsigned bkey_u64s = bkey_val_u64s(d.k);
+	unsigned bkey_bytes = bkey_u64s * sizeof(u64);
+	u64 last_u64 = ((u64*)d.v)[bkey_u64s - 1];
+#if CPU_BIG_ENDIAN
+	unsigned trailing_nuls = last_u64 ? __builtin_ctzll(last_u64) / 8 : 64 / 8;
+#else
+	unsigned trailing_nuls = last_u64 ? __builtin_clzll(last_u64) / 8 : 64 / 8;
+#endif
+
+	return bkey_bytes -
+		offsetof(struct bch_dirent, d_name) -
+		trailing_nuls;
+}
+
+struct qstr bch2_dirent_get_name(struct bkey_s_c_dirent d)
+{
+	return (struct qstr) QSTR_INIT(d.v->d_name, bch2_dirent_name_bytes(d));
+}
+
+static u64 bch2_dirent_hash(const struct bch_hash_info *info,
+			    const struct qstr *name)
+{
+	struct bch_str_hash_ctx ctx;
+
+	bch2_str_hash_init(&ctx, info);
+	bch2_str_hash_update(&ctx, info, name->name, name->len);
+
+	/* [0,2) reserved for dots */
+	return max_t(u64, bch2_str_hash_end(&ctx, info), 2);
+}
+
+static u64 dirent_hash_key(const struct bch_hash_info *info, const void *key)
+{
+	return bch2_dirent_hash(info, key);
+}
+
+static u64 dirent_hash_bkey(const struct bch_hash_info *info, struct bkey_s_c k)
+{
+	struct bkey_s_c_dirent d = bkey_s_c_to_dirent(k);
+	struct qstr name = bch2_dirent_get_name(d);
+
+	return bch2_dirent_hash(info, &name);
+}
+
+static bool dirent_cmp_key(struct bkey_s_c _l, const void *_r)
+{
+	struct bkey_s_c_dirent l = bkey_s_c_to_dirent(_l);
+	const struct qstr l_name = bch2_dirent_get_name(l);
+	const struct qstr *r_name = _r;
+
+	return l_name.len - r_name->len ?: memcmp(l_name.name, r_name->name, l_name.len);
+}
+
+static bool dirent_cmp_bkey(struct bkey_s_c _l, struct bkey_s_c _r)
+{
+	struct bkey_s_c_dirent l = bkey_s_c_to_dirent(_l);
+	struct bkey_s_c_dirent r = bkey_s_c_to_dirent(_r);
+	const struct qstr l_name = bch2_dirent_get_name(l);
+	const struct qstr r_name = bch2_dirent_get_name(r);
+
+	return l_name.len - r_name.len ?: memcmp(l_name.name, r_name.name, l_name.len);
+}
+
+static bool dirent_is_visible(subvol_inum inum, struct bkey_s_c k)
+{
+	struct bkey_s_c_dirent d = bkey_s_c_to_dirent(k);
+
+	if (d.v->d_type == DT_SUBVOL)
+		return le32_to_cpu(d.v->d_parent_subvol) == inum.subvol;
+	return true;
+}
+
+const struct bch_hash_desc bch2_dirent_hash_desc = {
+	.btree_id	= BTREE_ID_dirents,
+	.key_type	= KEY_TYPE_dirent,
+	.hash_key	= dirent_hash_key,
+	.hash_bkey	= dirent_hash_bkey,
+	.cmp_key	= dirent_cmp_key,
+	.cmp_bkey	= dirent_cmp_bkey,
+	.is_visible	= dirent_is_visible,
+};
+
+int bch2_dirent_invalid(struct bch_fs *c, struct bkey_s_c k,
+			enum bkey_invalid_flags flags,
+			struct printbuf *err)
+{
+	struct bkey_s_c_dirent d = bkey_s_c_to_dirent(k);
+	struct qstr d_name = bch2_dirent_get_name(d);
+	int ret = 0;
+
+	bkey_fsck_err_on(!d_name.len, c, err,
+			 dirent_empty_name,
+			 "empty name");
+
+	bkey_fsck_err_on(bkey_val_u64s(k.k) > dirent_val_u64s(d_name.len), c, err,
+			 dirent_val_too_big,
+			 "value too big (%zu > %u)",
+			 bkey_val_u64s(k.k), dirent_val_u64s(d_name.len));
+
+	/*
+	 * Check new keys don't exceed the max length
+	 * (older keys may be larger.)
+	 */
+	bkey_fsck_err_on((flags & BKEY_INVALID_COMMIT) && d_name.len > BCH_NAME_MAX, c, err,
+			 dirent_name_too_long,
+			 "dirent name too big (%u > %u)",
+			 d_name.len, BCH_NAME_MAX);
+
+	bkey_fsck_err_on(d_name.len != strnlen(d_name.name, d_name.len), c, err,
+			 dirent_name_embedded_nul,
+			 "dirent has stray data after name's NUL");
+
+	bkey_fsck_err_on((d_name.len == 1 && !memcmp(d_name.name, ".", 1)) ||
+			 (d_name.len == 2 && !memcmp(d_name.name, "..", 2)), c, err,
+			 dirent_name_dot_or_dotdot,
+			 "invalid name");
+
+	bkey_fsck_err_on(memchr(d_name.name, '/', d_name.len), c, err,
+			 dirent_name_has_slash,
+			 "name with /");
+
+	bkey_fsck_err_on(d.v->d_type != DT_SUBVOL &&
+			 le64_to_cpu(d.v->d_inum) == d.k->p.inode, c, err,
+			 dirent_to_itself,
+			 "dirent points to own directory");
+fsck_err:
+	return ret;
+}
+
+void bch2_dirent_to_text(struct printbuf *out, struct bch_fs *c,
+			 struct bkey_s_c k)
+{
+	struct bkey_s_c_dirent d = bkey_s_c_to_dirent(k);
+	struct qstr d_name = bch2_dirent_get_name(d);
+
+	prt_printf(out, "%.*s -> %llu type %s",
+	       d_name.len,
+	       d_name.name,
+	       d.v->d_type != DT_SUBVOL
+	       ? le64_to_cpu(d.v->d_inum)
+	       : le32_to_cpu(d.v->d_child_subvol),
+	       bch2_d_type_str(d.v->d_type));
+}
+
+static struct bkey_i_dirent *dirent_create_key(struct btree_trans *trans,
+				subvol_inum dir, u8 type,
+				const struct qstr *name, u64 dst)
+{
+	struct bkey_i_dirent *dirent;
+	unsigned u64s = BKEY_U64s + dirent_val_u64s(name->len);
+
+	if (name->len > BCH_NAME_MAX)
+		return ERR_PTR(-ENAMETOOLONG);
+
+	BUG_ON(u64s > U8_MAX);
+
+	dirent = bch2_trans_kmalloc(trans, u64s * sizeof(u64));
+	if (IS_ERR(dirent))
+		return dirent;
+
+	bkey_dirent_init(&dirent->k_i);
+	dirent->k.u64s = u64s;
+
+	if (type != DT_SUBVOL) {
+		dirent->v.d_inum = cpu_to_le64(dst);
+	} else {
+		dirent->v.d_parent_subvol = cpu_to_le32(dir.subvol);
+		dirent->v.d_child_subvol = cpu_to_le32(dst);
+	}
+
+	dirent->v.d_type = type;
+
+	memcpy(dirent->v.d_name, name->name, name->len);
+	memset(dirent->v.d_name + name->len, 0,
+	       bkey_val_bytes(&dirent->k) -
+	       offsetof(struct bch_dirent, d_name) -
+	       name->len);
+
+	EBUG_ON(bch2_dirent_name_bytes(dirent_i_to_s_c(dirent)) != name->len);
+
+	return dirent;
+}
+
+int bch2_dirent_create(struct btree_trans *trans, subvol_inum dir,
+		       const struct bch_hash_info *hash_info,
+		       u8 type, const struct qstr *name, u64 dst_inum,
+		       u64 *dir_offset, int flags)
+{
+	struct bkey_i_dirent *dirent;
+	int ret;
+
+	dirent = dirent_create_key(trans, dir, type, name, dst_inum);
+	ret = PTR_ERR_OR_ZERO(dirent);
+	if (ret)
+		return ret;
+
+	ret = bch2_hash_set(trans, bch2_dirent_hash_desc, hash_info,
+			    dir, &dirent->k_i, flags);
+	*dir_offset = dirent->k.p.offset;
+
+	return ret;
+}
+
+static void dirent_copy_target(struct bkey_i_dirent *dst,
+			       struct bkey_s_c_dirent src)
+{
+	dst->v.d_inum = src.v->d_inum;
+	dst->v.d_type = src.v->d_type;
+}
+
+int bch2_dirent_read_target(struct btree_trans *trans, subvol_inum dir,
+			    struct bkey_s_c_dirent d, subvol_inum *target)
+{
+	struct bch_subvolume s;
+	int ret = 0;
+
+	if (d.v->d_type == DT_SUBVOL &&
+	    le32_to_cpu(d.v->d_parent_subvol) != dir.subvol)
+		return 1;
+
+	if (likely(d.v->d_type != DT_SUBVOL)) {
+		target->subvol	= dir.subvol;
+		target->inum	= le64_to_cpu(d.v->d_inum);
+	} else {
+		target->subvol	= le32_to_cpu(d.v->d_child_subvol);
+
+		ret = bch2_subvolume_get(trans, target->subvol, true, BTREE_ITER_CACHED, &s);
+
+		target->inum	= le64_to_cpu(s.inode);
+	}
+
+	return ret;
+}
+
+int bch2_dirent_rename(struct btree_trans *trans,
+		subvol_inum src_dir, struct bch_hash_info *src_hash,
+		subvol_inum dst_dir, struct bch_hash_info *dst_hash,
+		const struct qstr *src_name, subvol_inum *src_inum, u64 *src_offset,
+		const struct qstr *dst_name, subvol_inum *dst_inum, u64 *dst_offset,
+		enum bch_rename_mode mode)
+{
+	struct btree_iter src_iter = { NULL };
+	struct btree_iter dst_iter = { NULL };
+	struct bkey_s_c old_src, old_dst = bkey_s_c_null;
+	struct bkey_i_dirent *new_src = NULL, *new_dst = NULL;
+	struct bpos dst_pos =
+		POS(dst_dir.inum, bch2_dirent_hash(dst_hash, dst_name));
+	unsigned src_type = 0, dst_type = 0, src_update_flags = 0;
+	int ret = 0;
+
+	if (src_dir.subvol != dst_dir.subvol)
+		return -EXDEV;
+
+	memset(src_inum, 0, sizeof(*src_inum));
+	memset(dst_inum, 0, sizeof(*dst_inum));
+
+	/* Lookup src: */
+	ret = bch2_hash_lookup(trans, &src_iter, bch2_dirent_hash_desc,
+			       src_hash, src_dir, src_name,
+			       BTREE_ITER_INTENT);
+	if (ret)
+		goto out;
+
+	old_src = bch2_btree_iter_peek_slot(&src_iter);
+	ret = bkey_err(old_src);
+	if (ret)
+		goto out;
+
+	ret = bch2_dirent_read_target(trans, src_dir,
+			bkey_s_c_to_dirent(old_src), src_inum);
+	if (ret)
+		goto out;
+
+	src_type = bkey_s_c_to_dirent(old_src).v->d_type;
+
+	if (src_type == DT_SUBVOL && mode == BCH_RENAME_EXCHANGE)
+		return -EOPNOTSUPP;
+
+
+	/* Lookup dst: */
+	if (mode == BCH_RENAME) {
+		/*
+		 * Note that we're _not_ checking if the target already exists -
+		 * we're relying on the VFS to do that check for us for
+		 * correctness:
+		 */
+		ret = bch2_hash_hole(trans, &dst_iter, bch2_dirent_hash_desc,
+				     dst_hash, dst_dir, dst_name);
+		if (ret)
+			goto out;
+	} else {
+		ret = bch2_hash_lookup(trans, &dst_iter, bch2_dirent_hash_desc,
+				       dst_hash, dst_dir, dst_name,
+				       BTREE_ITER_INTENT);
+		if (ret)
+			goto out;
+
+		old_dst = bch2_btree_iter_peek_slot(&dst_iter);
+		ret = bkey_err(old_dst);
+		if (ret)
+			goto out;
+
+		ret = bch2_dirent_read_target(trans, dst_dir,
+				bkey_s_c_to_dirent(old_dst), dst_inum);
+		if (ret)
+			goto out;
+
+		dst_type = bkey_s_c_to_dirent(old_dst).v->d_type;
+
+		if (dst_type == DT_SUBVOL)
+			return -EOPNOTSUPP;
+	}
+
+	if (mode != BCH_RENAME_EXCHANGE)
+		*src_offset = dst_iter.pos.offset;
+
+	/* Create new dst key: */
+	new_dst = dirent_create_key(trans, dst_dir, 0, dst_name, 0);
+	ret = PTR_ERR_OR_ZERO(new_dst);
+	if (ret)
+		goto out;
+
+	dirent_copy_target(new_dst, bkey_s_c_to_dirent(old_src));
+	new_dst->k.p = dst_iter.pos;
+
+	/* Create new src key: */
+	if (mode == BCH_RENAME_EXCHANGE) {
+		new_src = dirent_create_key(trans, src_dir, 0, src_name, 0);
+		ret = PTR_ERR_OR_ZERO(new_src);
+		if (ret)
+			goto out;
+
+		dirent_copy_target(new_src, bkey_s_c_to_dirent(old_dst));
+		new_src->k.p = src_iter.pos;
+	} else {
+		new_src = bch2_trans_kmalloc(trans, sizeof(struct bkey_i));
+		ret = PTR_ERR_OR_ZERO(new_src);
+		if (ret)
+			goto out;
+
+		bkey_init(&new_src->k);
+		new_src->k.p = src_iter.pos;
+
+		if (bkey_le(dst_pos, src_iter.pos) &&
+		    bkey_lt(src_iter.pos, dst_iter.pos)) {
+			/*
+			 * We have a hash collision for the new dst key,
+			 * and new_src - the key we're deleting - is between
+			 * new_dst's hashed slot and the slot we're going to be
+			 * inserting it into - oops.  This will break the hash
+			 * table if we don't deal with it:
+			 */
+			if (mode == BCH_RENAME) {
+				/*
+				 * If we're not overwriting, we can just insert
+				 * new_dst at the src position:
+				 */
+				new_src = new_dst;
+				new_src->k.p = src_iter.pos;
+				goto out_set_src;
+			} else {
+				/* If we're overwriting, we can't insert new_dst
+				 * at a different slot because it has to
+				 * overwrite old_dst - just make sure to use a
+				 * whiteout when deleting src:
+				 */
+				new_src->k.type = KEY_TYPE_hash_whiteout;
+			}
+		} else {
+			/* Check if we need a whiteout to delete src: */
+			ret = bch2_hash_needs_whiteout(trans, bch2_dirent_hash_desc,
+						       src_hash, &src_iter);
+			if (ret < 0)
+				goto out;
+
+			if (ret)
+				new_src->k.type = KEY_TYPE_hash_whiteout;
+		}
+	}
+
+	ret = bch2_trans_update(trans, &dst_iter, &new_dst->k_i, 0);
+	if (ret)
+		goto out;
+out_set_src:
+
+	/*
+	 * If we're deleting a subvolume, we need to really delete the dirent,
+	 * not just emit a whiteout in the current snapshot:
+	 */
+	if (src_type == DT_SUBVOL) {
+		bch2_btree_iter_set_snapshot(&src_iter, old_src.k->p.snapshot);
+		ret = bch2_btree_iter_traverse(&src_iter);
+		if (ret)
+			goto out;
+
+		new_src->k.p = src_iter.pos;
+		src_update_flags |= BTREE_UPDATE_INTERNAL_SNAPSHOT_NODE;
+	}
+
+	ret = bch2_trans_update(trans, &src_iter, &new_src->k_i, src_update_flags);
+	if (ret)
+		goto out;
+
+	if (mode == BCH_RENAME_EXCHANGE)
+		*src_offset = new_src->k.p.offset;
+	*dst_offset = new_dst->k.p.offset;
+out:
+	bch2_trans_iter_exit(trans, &src_iter);
+	bch2_trans_iter_exit(trans, &dst_iter);
+	return ret;
+}
+
+int __bch2_dirent_lookup_trans(struct btree_trans *trans,
+			       struct btree_iter *iter,
+			       subvol_inum dir,
+			       const struct bch_hash_info *hash_info,
+			       const struct qstr *name, subvol_inum *inum,
+			       unsigned flags)
+{
+	struct bkey_s_c k;
+	struct bkey_s_c_dirent d;
+	u32 snapshot;
+	int ret;
+
+	ret = bch2_subvolume_get_snapshot(trans, dir.subvol, &snapshot);
+	if (ret)
+		return ret;
+
+	ret = bch2_hash_lookup(trans, iter, bch2_dirent_hash_desc,
+			       hash_info, dir, name, flags);
+	if (ret)
+		return ret;
+
+	k = bch2_btree_iter_peek_slot(iter);
+	ret = bkey_err(k);
+	if (ret)
+		goto err;
+
+	d = bkey_s_c_to_dirent(k);
+
+	ret = bch2_dirent_read_target(trans, dir, d, inum);
+	if (ret > 0)
+		ret = -ENOENT;
+err:
+	if (ret)
+		bch2_trans_iter_exit(trans, iter);
+
+	return ret;
+}
+
+u64 bch2_dirent_lookup(struct bch_fs *c, subvol_inum dir,
+		       const struct bch_hash_info *hash_info,
+		       const struct qstr *name, subvol_inum *inum)
+{
+	struct btree_trans *trans = bch2_trans_get(c);
+	struct btree_iter iter;
+	int ret;
+retry:
+	bch2_trans_begin(trans);
+
+	ret = __bch2_dirent_lookup_trans(trans, &iter, dir, hash_info,
+					  name, inum, 0);
+	if (bch2_err_matches(ret, BCH_ERR_transaction_restart))
+		goto retry;
+	if (!ret)
+		bch2_trans_iter_exit(trans, &iter);
+	bch2_trans_put(trans);
+	return ret;
+}
+
+int bch2_empty_dir_snapshot(struct btree_trans *trans, u64 dir, u32 snapshot)
+{
+	struct btree_iter iter;
+	struct bkey_s_c k;
+	int ret;
+
+	for_each_btree_key_upto_norestart(trans, iter, BTREE_ID_dirents,
+			   SPOS(dir, 0, snapshot),
+			   POS(dir, U64_MAX), 0, k, ret)
+		if (k.k->type == KEY_TYPE_dirent) {
+			ret = -ENOTEMPTY;
+			break;
+		}
+	bch2_trans_iter_exit(trans, &iter);
+
+	return ret;
+}
+
+int bch2_empty_dir_trans(struct btree_trans *trans, subvol_inum dir)
+{
+	u32 snapshot;
+
+	return bch2_subvolume_get_snapshot(trans, dir.subvol, &snapshot) ?:
+		bch2_empty_dir_snapshot(trans, dir.inum, snapshot);
+}
+
+int bch2_readdir(struct bch_fs *c, subvol_inum inum, struct dir_context *ctx)
+{
+	struct btree_trans *trans = bch2_trans_get(c);
+	struct btree_iter iter;
+	struct bkey_s_c k;
+	struct bkey_s_c_dirent dirent;
+	subvol_inum target;
+	u32 snapshot;
+	struct bkey_buf sk;
+	struct qstr name;
+	int ret;
+
+	bch2_bkey_buf_init(&sk);
+retry:
+	bch2_trans_begin(trans);
+
+	ret = bch2_subvolume_get_snapshot(trans, inum.subvol, &snapshot);
+	if (ret)
+		goto err;
+
+	for_each_btree_key_upto_norestart(trans, iter, BTREE_ID_dirents,
+			   SPOS(inum.inum, ctx->pos, snapshot),
+			   POS(inum.inum, U64_MAX), 0, k, ret) {
+		if (k.k->type != KEY_TYPE_dirent)
+			continue;
+
+		dirent = bkey_s_c_to_dirent(k);
+
+		ret = bch2_dirent_read_target(trans, inum, dirent, &target);
+		if (ret < 0)
+			break;
+		if (ret)
+			continue;
+
+		/* dir_emit() can fault and block: */
+		bch2_bkey_buf_reassemble(&sk, c, k);
+		dirent = bkey_i_to_s_c_dirent(sk.k);
+		bch2_trans_unlock(trans);
+
+		name = bch2_dirent_get_name(dirent);
+
+		ctx->pos = dirent.k->p.offset;
+		if (!dir_emit(ctx, name.name,
+			      name.len,
+			      target.inum,
+			      vfs_d_type(dirent.v->d_type)))
+			break;
+		ctx->pos = dirent.k->p.offset + 1;
+
+		/*
+		 * read_target looks up subvolumes, we can overflow paths if the
+		 * directory has many subvolumes in it
+		 */
+		ret = btree_trans_too_many_iters(trans);
+		if (ret)
+			break;
+	}
+	bch2_trans_iter_exit(trans, &iter);
+err:
+	if (bch2_err_matches(ret, BCH_ERR_transaction_restart))
+		goto retry;
+
+	bch2_trans_put(trans);
+	bch2_bkey_buf_exit(&sk, c);
+
+	return ret;
+}