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-rw-r--r--fs/bcachefs/dirent.c580
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;
+}