1 files changed, 426 insertions, 0 deletions

diff --git a/fs/bcachefs/dirent.c b/fs/bcachefs/dirent.c
new file mode 100644
index 000000000000..9e5936faf1af
--- /dev/null
+++ b/fs/bcachefs/dirent.c
@@ -0,0 +1,426 @@
+// SPDX-License-Identifier: GPL-2.0
+
+#include "bcachefs.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 <linux/dcache.h>
+
+unsigned bch2_dirent_name_bytes(struct bkey_s_c_dirent d)
+{
+	unsigned len = bkey_val_bytes(d.k) -
+		offsetof(struct bch_dirent, d_name);
+
+	while (len && !d.v->d_name[len - 1])
+		--len;
+
+	return len;
+}
+
+static unsigned dirent_val_u64s(unsigned len)
+{
+	return DIV_ROUND_UP(offsetof(struct bch_dirent, d_name) + len,
+			    sizeof(u64));
+}
+
+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 = QSTR_INIT(d.v->d_name, bch2_dirent_name_bytes(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);
+	int len = bch2_dirent_name_bytes(l);
+	const struct qstr *r = _r;
+
+	return len - r->len ?: memcmp(l.v->d_name, r->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);
+	int l_len = bch2_dirent_name_bytes(l);
+	int r_len = bch2_dirent_name_bytes(r);
+
+	return l_len - r_len ?: memcmp(l.v->d_name, r.v->d_name, l_len);
+}
+
+const struct bch_hash_desc bch2_dirent_hash_desc = {
+	.btree_id	= BTREE_ID_DIRENTS,
+	.key_type	= BCH_DIRENT,
+	.whiteout_type	= BCH_DIRENT_WHITEOUT,
+	.hash_key	= dirent_hash_key,
+	.hash_bkey	= dirent_hash_bkey,
+	.cmp_key	= dirent_cmp_key,
+	.cmp_bkey	= dirent_cmp_bkey,
+};
+
+const char *bch2_dirent_invalid(const struct bch_fs *c, struct bkey_s_c k)
+{
+	struct bkey_s_c_dirent d;
+	unsigned len;
+
+	switch (k.k->type) {
+	case BCH_DIRENT:
+		if (bkey_val_bytes(k.k) < sizeof(struct bch_dirent))
+			return "value too small";
+
+		d = bkey_s_c_to_dirent(k);
+		len = bch2_dirent_name_bytes(d);
+
+		if (!len)
+			return "empty name";
+
+		/*
+		 * older versions of bcachefs were buggy and creating dirent
+		 * keys that were bigger than necessary:
+		 */
+		if (bkey_val_u64s(k.k) > dirent_val_u64s(len + 7))
+			return "value too big";
+
+		if (len > BCH_NAME_MAX)
+			return "dirent name too big";
+
+		if (memchr(d.v->d_name, '/', len))
+			return "dirent name has invalid characters";
+
+		return NULL;
+	case BCH_DIRENT_WHITEOUT:
+		return bkey_val_bytes(k.k) != 0
+			? "value size should be zero"
+			: NULL;
+
+	default:
+		return "invalid type";
+	}
+}
+
+void bch2_dirent_to_text(struct bch_fs *c, char *buf,
+			 size_t size, struct bkey_s_c k)
+{
+	struct bkey_s_c_dirent d;
+	size_t n = 0;
+
+	switch (k.k->type) {
+	case BCH_DIRENT:
+		d = bkey_s_c_to_dirent(k);
+
+		n += bch_scnmemcpy(buf + n, size - n, d.v->d_name,
+				   bch2_dirent_name_bytes(d));
+		n += scnprintf(buf + n, size - n, " -> %llu", d.v->d_inum);
+		break;
+	case BCH_DIRENT_WHITEOUT:
+		scnprintf(buf, size, "whiteout");
+		break;
+	}
+}
+
+static struct bkey_i_dirent *dirent_create_key(struct btree_trans *trans,
+				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;
+	dirent->v.d_inum = cpu_to_le64(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,
+			 u64 dir_inum, const struct bch_hash_info *hash_info,
+			 u8 type, const struct qstr *name, u64 dst_inum,
+			 int flags)
+{
+	struct bkey_i_dirent *dirent;
+	int ret;
+
+	dirent = dirent_create_key(trans, type, name, dst_inum);
+	ret = PTR_ERR_OR_ZERO(dirent);
+	if (ret)
+		return ret;
+
+	return __bch2_hash_set(trans, bch2_dirent_hash_desc, hash_info,
+			       dir_inum, &dirent->k_i, flags);
+}
+
+int bch2_dirent_create(struct bch_fs *c, u64 dir_inum,
+		       const struct bch_hash_info *hash_info,
+		       u8 type, const struct qstr *name, u64 dst_inum,
+		       u64 *journal_seq, int flags)
+{
+	return bch2_trans_do(c, journal_seq, flags,
+		__bch2_dirent_create(&trans, dir_inum, hash_info,
+				     type, name, dst_inum, flags));
+}
+
+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;
+}
+
+static struct bpos bch2_dirent_pos(struct bch_inode_info *inode,
+				   const struct qstr *name)
+{
+	return POS(inode->v.i_ino, bch2_dirent_hash(&inode->ei_str_hash, name));
+}
+
+int bch2_dirent_rename(struct btree_trans *trans,
+		struct bch_inode_info *src_dir, const struct qstr *src_name,
+		struct bch_inode_info *dst_dir, const struct qstr *dst_name,
+		enum bch_rename_mode mode)
+{
+	struct btree_iter *src_iter, *dst_iter;
+	struct bkey_s_c old_src, old_dst;
+	struct bkey_i_dirent *new_src = NULL, *new_dst = NULL;
+	struct bpos dst_pos = bch2_dirent_pos(dst_dir, dst_name);
+	int ret;
+
+	/*
+	 * Lookup dst:
+	 *
+	 * Note that in BCH_RENAME mode, we're _not_ checking if
+	 * the target already exists - we're relying on the VFS
+	 * to do that check for us for correctness:
+	 */
+	dst_iter = mode == BCH_RENAME
+		? bch2_hash_hole(trans, bch2_dirent_hash_desc,
+				 &dst_dir->ei_str_hash,
+				 dst_dir->v.i_ino, dst_name)
+		: bch2_hash_lookup(trans, bch2_dirent_hash_desc,
+				   &dst_dir->ei_str_hash,
+				   dst_dir->v.i_ino, dst_name,
+				   BTREE_ITER_INTENT);
+	if (IS_ERR(dst_iter))
+		return PTR_ERR(dst_iter);
+	old_dst = bch2_btree_iter_peek_slot(dst_iter);
+
+	/* Lookup src: */
+	src_iter = bch2_hash_lookup(trans, bch2_dirent_hash_desc,
+				    &src_dir->ei_str_hash,
+				    src_dir->v.i_ino, src_name,
+				    BTREE_ITER_INTENT);
+	if (IS_ERR(src_iter))
+		return PTR_ERR(src_iter);
+	old_src = bch2_btree_iter_peek_slot(src_iter);
+
+	/* Create new dst key: */
+	new_dst = dirent_create_key(trans, 0, dst_name, 0);
+	if (IS_ERR(new_dst))
+		return PTR_ERR(new_dst);
+
+	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, 0, src_name, 0);
+		if (IS_ERR(new_src))
+			return PTR_ERR(new_src);
+
+		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));
+		if (IS_ERR(new_src))
+			return PTR_ERR(new_src);
+		bkey_init(&new_src->k);
+		new_src->k.p = src_iter->pos;
+
+		if (bkey_cmp(dst_pos, src_iter->pos) <= 0 &&
+		    bkey_cmp(src_iter->pos, dst_iter->pos) < 0) {
+			/*
+			 * 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_dst->k.p = src_iter->pos;
+				bch2_trans_update(trans, src_iter, &new_dst->k_i, 0);
+				return 0;
+			} 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 = BCH_DIRENT_WHITEOUT;
+			}
+		} else {
+			/* Check if we need a whiteout to delete src: */
+			ret = bch2_hash_needs_whiteout(trans, bch2_dirent_hash_desc,
+						       &src_dir->ei_str_hash,
+						       src_iter);
+			if (ret < 0)
+				return ret;
+
+			if (ret)
+				new_src->k.type = BCH_DIRENT_WHITEOUT;
+		}
+	}
+
+	bch2_trans_update(trans, src_iter, &new_src->k_i, 0);
+	bch2_trans_update(trans, dst_iter, &new_dst->k_i, 0);
+	return 0;
+}
+
+int __bch2_dirent_delete(struct btree_trans *trans, u64 dir_inum,
+			 const struct bch_hash_info *hash_info,
+			 const struct qstr *name)
+{
+	return bch2_hash_delete(trans, bch2_dirent_hash_desc, hash_info,
+				dir_inum, name);
+}
+
+int bch2_dirent_delete(struct bch_fs *c, u64 dir_inum,
+		       const struct bch_hash_info *hash_info,
+		       const struct qstr *name,
+		       u64 *journal_seq)
+{
+	return bch2_trans_do(c, journal_seq,
+			     BTREE_INSERT_ATOMIC|
+			     BTREE_INSERT_NOFAIL,
+		__bch2_dirent_delete(&trans, dir_inum, hash_info, name));
+}
+
+u64 bch2_dirent_lookup(struct bch_fs *c, u64 dir_inum,
+		       const struct bch_hash_info *hash_info,
+		       const struct qstr *name)
+{
+	struct btree_trans trans;
+	struct btree_iter *iter;
+	struct bkey_s_c k;
+	u64 inum = 0;
+
+	bch2_trans_init(&trans, c);
+
+	iter = bch2_hash_lookup(&trans, bch2_dirent_hash_desc,
+				hash_info, dir_inum, name, 0);
+	if (IS_ERR(iter)) {
+		BUG_ON(PTR_ERR(iter) == -EINTR);
+		goto out;
+	}
+
+	k = bch2_btree_iter_peek_slot(iter);
+	inum = le64_to_cpu(bkey_s_c_to_dirent(k).v->d_inum);
+out:
+	bch2_trans_exit(&trans);
+	return inum;
+}
+
+int bch2_empty_dir(struct bch_fs *c, u64 dir_inum)
+{
+	struct btree_iter iter;
+	struct bkey_s_c k;
+	int ret = 0;
+
+	for_each_btree_key(&iter, c, BTREE_ID_DIRENTS, POS(dir_inum, 0), 0, k) {
+		if (k.k->p.inode > dir_inum)
+			break;
+
+		if (k.k->type == BCH_DIRENT) {
+			ret = -ENOTEMPTY;
+			break;
+		}
+	}
+	bch2_btree_iter_unlock(&iter);
+
+	return ret;
+}
+
+int bch2_readdir(struct bch_fs *c, struct file *file,
+		 struct dir_context *ctx)
+{
+	struct bch_inode_info *inode = file_bch_inode(file);
+	struct btree_iter iter;
+	struct bkey_s_c k;
+	struct bkey_s_c_dirent dirent;
+	unsigned len;
+
+	if (!dir_emit_dots(file, ctx))
+		return 0;
+
+	for_each_btree_key(&iter, c, BTREE_ID_DIRENTS,
+			   POS(inode->v.i_ino, ctx->pos), 0, k) {
+		if (k.k->type != BCH_DIRENT)
+			continue;
+
+		dirent = bkey_s_c_to_dirent(k);
+
+		if (bkey_cmp(k.k->p, POS(inode->v.i_ino, ctx->pos)) < 0)
+			continue;
+
+		if (k.k->p.inode > inode->v.i_ino)
+			break;
+
+		len = bch2_dirent_name_bytes(dirent);
+
+		/*
+		 * XXX: dir_emit() can fault and block, while we're holding
+		 * locks
+		 */
+		if (!dir_emit(ctx, dirent.v->d_name, len,
+			      le64_to_cpu(dirent.v->d_inum),
+			      dirent.v->d_type))
+			break;
+
+		ctx->pos = k.k->p.offset + 1;
+	}
+	bch2_btree_iter_unlock(&iter);
+
+	return 0;
+}