bcachefs: Initial commit

Initially forked from drivers/md/bcache, bcachefs is a new copy-on-write
filesystem with every feature you could possibly want.

Website: https://bcachefs.org

Signed-off-by: Kent Overstreet <kent.overstreet@linux.dev>

1 files changed, 387 insertions, 0 deletions

diff --git a/fs/bcachefs/acl.c b/fs/bcachefs/acl.c
new file mode 100644
index 000000000000..eaf5c8e138fb
--- /dev/null
+++ b/fs/bcachefs/acl.c
@@ -0,0 +1,387 @@
+// SPDX-License-Identifier: GPL-2.0
+#ifdef CONFIG_BCACHEFS_POSIX_ACL
+
+#include "bcachefs.h"
+
+#include <linux/fs.h>
+#include <linux/posix_acl.h>
+#include <linux/posix_acl_xattr.h>
+#include <linux/sched.h>
+#include <linux/slab.h>
+
+#include "acl.h"
+#include "fs.h"
+#include "xattr.h"
+
+static inline size_t bch2_acl_size(unsigned nr_short, unsigned nr_long)
+{
+	return sizeof(bch_acl_header) +
+		sizeof(bch_acl_entry_short) * nr_short +
+		sizeof(bch_acl_entry) * nr_long;
+}
+
+static inline int acl_to_xattr_type(int type)
+{
+	switch (type) {
+	case ACL_TYPE_ACCESS:
+		return BCH_XATTR_INDEX_POSIX_ACL_ACCESS;
+	case ACL_TYPE_DEFAULT:
+		return BCH_XATTR_INDEX_POSIX_ACL_DEFAULT;
+	default:
+		BUG();
+	}
+}
+
+/*
+ * Convert from filesystem to in-memory representation.
+ */
+static struct posix_acl *bch2_acl_from_disk(const void *value, size_t size)
+{
+	const void *p, *end = value + size;
+	struct posix_acl *acl;
+	struct posix_acl_entry *out;
+	unsigned count = 0;
+
+	if (!value)
+		return NULL;
+	if (size < sizeof(bch_acl_header))
+		goto invalid;
+	if (((bch_acl_header *)value)->a_version !=
+	    cpu_to_le32(BCH_ACL_VERSION))
+		goto invalid;
+
+	p = value + sizeof(bch_acl_header);
+	while (p < end) {
+		const bch_acl_entry *entry = p;
+
+		if (p + sizeof(bch_acl_entry_short) > end)
+			goto invalid;
+
+		switch (le16_to_cpu(entry->e_tag)) {
+		case ACL_USER_OBJ:
+		case ACL_GROUP_OBJ:
+		case ACL_MASK:
+		case ACL_OTHER:
+			p += sizeof(bch_acl_entry_short);
+			break;
+		case ACL_USER:
+		case ACL_GROUP:
+			p += sizeof(bch_acl_entry);
+			break;
+		default:
+			goto invalid;
+		}
+
+		count++;
+	}
+
+	if (p > end)
+		goto invalid;
+
+	if (!count)
+		return NULL;
+
+	acl = posix_acl_alloc(count, GFP_KERNEL);
+	if (!acl)
+		return ERR_PTR(-ENOMEM);
+
+	out = acl->a_entries;
+
+	p = value + sizeof(bch_acl_header);
+	while (p < end) {
+		const bch_acl_entry *in = p;
+
+		out->e_tag  = le16_to_cpu(in->e_tag);
+		out->e_perm = le16_to_cpu(in->e_perm);
+
+		switch (out->e_tag) {
+		case ACL_USER_OBJ:
+		case ACL_GROUP_OBJ:
+		case ACL_MASK:
+		case ACL_OTHER:
+			p += sizeof(bch_acl_entry_short);
+			break;
+		case ACL_USER:
+			out->e_uid = make_kuid(&init_user_ns,
+					       le32_to_cpu(in->e_id));
+			p += sizeof(bch_acl_entry);
+			break;
+		case ACL_GROUP:
+			out->e_gid = make_kgid(&init_user_ns,
+					       le32_to_cpu(in->e_id));
+			p += sizeof(bch_acl_entry);
+			break;
+		}
+
+		out++;
+	}
+
+	BUG_ON(out != acl->a_entries + acl->a_count);
+
+	return acl;
+invalid:
+	pr_err("invalid acl entry");
+	return ERR_PTR(-EINVAL);
+}
+
+#define acl_for_each_entry(acl, acl_e)			\
+	for (acl_e = acl->a_entries;			\
+	     acl_e < acl->a_entries + acl->a_count;	\
+	     acl_e++)
+
+/*
+ * Convert from in-memory to filesystem representation.
+ */
+static struct bkey_i_xattr *
+bch2_acl_to_xattr(struct btree_trans *trans,
+		  const struct posix_acl *acl,
+		  int type)
+{
+	struct bkey_i_xattr *xattr;
+	bch_acl_header *acl_header;
+	const struct posix_acl_entry *acl_e;
+	void *outptr;
+	unsigned nr_short = 0, nr_long = 0, acl_len, u64s;
+
+	acl_for_each_entry(acl, acl_e) {
+		switch (acl_e->e_tag) {
+		case ACL_USER:
+		case ACL_GROUP:
+			nr_long++;
+			break;
+		case ACL_USER_OBJ:
+		case ACL_GROUP_OBJ:
+		case ACL_MASK:
+		case ACL_OTHER:
+			nr_short++;
+			break;
+		default:
+			return ERR_PTR(-EINVAL);
+		}
+	}
+
+	acl_len = bch2_acl_size(nr_short, nr_long);
+	u64s = BKEY_U64s + xattr_val_u64s(0, acl_len);
+
+	if (u64s > U8_MAX)
+		return ERR_PTR(-E2BIG);
+
+	xattr = bch2_trans_kmalloc(trans, u64s * sizeof(u64));
+	if (IS_ERR(xattr))
+		return xattr;
+
+	bkey_xattr_init(&xattr->k_i);
+	xattr->k.u64s		= u64s;
+	xattr->v.x_type		= acl_to_xattr_type(type);
+	xattr->v.x_name_len	= 0,
+	xattr->v.x_val_len	= cpu_to_le16(acl_len);
+
+	acl_header = xattr_val(&xattr->v);
+	acl_header->a_version = cpu_to_le32(BCH_ACL_VERSION);
+
+	outptr = (void *) acl_header + sizeof(*acl_header);
+
+	acl_for_each_entry(acl, acl_e) {
+		bch_acl_entry *entry = outptr;
+
+		entry->e_tag = cpu_to_le16(acl_e->e_tag);
+		entry->e_perm = cpu_to_le16(acl_e->e_perm);
+		switch (acl_e->e_tag) {
+		case ACL_USER:
+			entry->e_id = cpu_to_le32(
+				from_kuid(&init_user_ns, acl_e->e_uid));
+			outptr += sizeof(bch_acl_entry);
+			break;
+		case ACL_GROUP:
+			entry->e_id = cpu_to_le32(
+				from_kgid(&init_user_ns, acl_e->e_gid));
+			outptr += sizeof(bch_acl_entry);
+			break;
+
+		case ACL_USER_OBJ:
+		case ACL_GROUP_OBJ:
+		case ACL_MASK:
+		case ACL_OTHER:
+			outptr += sizeof(bch_acl_entry_short);
+			break;
+		}
+	}
+
+	BUG_ON(outptr != xattr_val(&xattr->v) + acl_len);
+
+	return xattr;
+}
+
+struct posix_acl *bch2_get_acl(struct mnt_idmap *idmap,
+			       struct dentry *dentry, int type)
+{
+	struct bch_inode_info *inode = to_bch_ei(dentry->d_inode);
+	struct bch_fs *c = inode->v.i_sb->s_fs_info;
+	struct btree_trans trans;
+	struct btree_iter *iter;
+	struct bkey_s_c_xattr xattr;
+	struct posix_acl *acl = NULL;
+
+	bch2_trans_init(&trans, c);
+retry:
+	bch2_trans_begin(&trans);
+
+	iter = bch2_hash_lookup(&trans, bch2_xattr_hash_desc,
+			&inode->ei_str_hash, inode->v.i_ino,
+			&X_SEARCH(acl_to_xattr_type(type), "", 0),
+			0);
+	if (IS_ERR(iter)) {
+		if (PTR_ERR(iter) == -EINTR)
+			goto retry;
+
+		if (PTR_ERR(iter) != -ENOENT)
+			acl = ERR_CAST(iter);
+		goto out;
+	}
+
+	xattr = bkey_s_c_to_xattr(bch2_btree_iter_peek_slot(iter));
+
+	acl = bch2_acl_from_disk(xattr_val(xattr.v),
+			le16_to_cpu(xattr.v->x_val_len));
+
+	if (!IS_ERR(acl))
+		set_cached_acl(&inode->v, type, acl);
+out:
+	bch2_trans_exit(&trans);
+	return acl;
+}
+
+int bch2_set_acl_trans(struct btree_trans *trans,
+		       struct bch_inode_unpacked *inode_u,
+		       const struct bch_hash_info *hash_info,
+		       struct posix_acl *acl, int type)
+{
+	int ret;
+
+	if (type == ACL_TYPE_DEFAULT &&
+	    !S_ISDIR(inode_u->bi_mode))
+		return acl ? -EACCES : 0;
+
+	if (acl) {
+		struct bkey_i_xattr *xattr =
+			bch2_acl_to_xattr(trans, acl, type);
+		if (IS_ERR(xattr))
+			return PTR_ERR(xattr);
+
+		ret = __bch2_hash_set(trans, bch2_xattr_hash_desc, hash_info,
+				      inode_u->bi_inum, &xattr->k_i, 0);
+	} else {
+		struct xattr_search_key search =
+			X_SEARCH(acl_to_xattr_type(type), "", 0);
+
+		ret = bch2_hash_delete(trans, bch2_xattr_hash_desc, hash_info,
+				       inode_u->bi_inum, &search);
+	}
+
+	return ret == -ENOENT ? 0 : ret;
+}
+
+static int inode_update_for_set_acl_fn(struct bch_inode_info *inode,
+				       struct bch_inode_unpacked *bi,
+				       void *p)
+{
+	struct bch_fs *c = inode->v.i_sb->s_fs_info;
+	struct timespec64 now = current_time(&inode->v);
+	umode_t mode = (unsigned long) p;
+
+	bi->bi_ctime	= timespec_to_bch2_time(c, now);
+	bi->bi_mode	= mode;
+	return 0;
+}
+
+int bch2_set_acl(struct mnt_idmap *idmap,
+		 struct dentry *dentry,
+		 struct posix_acl *acl, int type)
+{
+	struct bch_inode_info *inode = to_bch_ei(dentry->d_inode);
+	struct bch_fs *c = inode->v.i_sb->s_fs_info;
+	struct btree_trans trans;
+	struct bch_inode_unpacked inode_u;
+	umode_t mode = inode->v.i_mode;
+	int ret;
+
+	if (type == ACL_TYPE_ACCESS && acl) {
+		ret = posix_acl_update_mode(idmap, &inode->v, &mode, &acl);
+		if (ret)
+			return ret;
+	}
+
+	bch2_trans_init(&trans, c);
+retry:
+	bch2_trans_begin(&trans);
+
+	ret   = bch2_set_acl_trans(&trans,
+				   &inode->ei_inode,
+				   &inode->ei_str_hash,
+				   acl, type) ?:
+		bch2_write_inode_trans(&trans, inode, &inode_u,
+				       inode_update_for_set_acl_fn,
+				       (void *)(unsigned long) mode) ?:
+		bch2_trans_commit(&trans, NULL, NULL,
+				  &inode->ei_journal_seq,
+				  BTREE_INSERT_ATOMIC|
+				  BTREE_INSERT_NOUNLOCK);
+	if (ret == -EINTR)
+		goto retry;
+	if (unlikely(ret))
+		goto err;
+
+	bch2_inode_update_after_write(c, inode, &inode_u,
+				      ATTR_CTIME|ATTR_MODE);
+
+	set_cached_acl(&inode->v, type, acl);
+err:
+	bch2_trans_exit(&trans);
+
+	return ret;
+}
+
+int bch2_acl_chmod(struct btree_trans *trans,
+		   struct bch_inode_info *inode,
+		   umode_t mode,
+		   struct posix_acl **new_acl)
+{
+	struct btree_iter *iter;
+	struct bkey_s_c_xattr xattr;
+	struct bkey_i_xattr *new;
+	struct posix_acl *acl;
+	int ret = 0;
+
+	iter = bch2_hash_lookup(trans, bch2_xattr_hash_desc,
+			&inode->ei_str_hash, inode->v.i_ino,
+			&X_SEARCH(BCH_XATTR_INDEX_POSIX_ACL_ACCESS, "", 0),
+			BTREE_ITER_INTENT);
+	if (IS_ERR(iter))
+		return PTR_ERR(iter) != -ENOENT ? PTR_ERR(iter) : 0;
+
+	xattr = bkey_s_c_to_xattr(bch2_btree_iter_peek_slot(iter));
+
+	acl = bch2_acl_from_disk(xattr_val(xattr.v),
+			le16_to_cpu(xattr.v->x_val_len));
+	if (IS_ERR_OR_NULL(acl))
+		return PTR_ERR(acl);
+
+	ret = __posix_acl_chmod(&acl, GFP_KERNEL, mode);
+	if (ret)
+		goto err;
+
+	new = bch2_acl_to_xattr(trans, acl, ACL_TYPE_ACCESS);
+	if (IS_ERR(new)) {
+		ret = PTR_ERR(new);
+		goto err;
+	}
+
+	bch2_trans_update(trans, iter, &new->k_i, 0);
+	*new_acl = acl;
+	acl = NULL;
+err:
+	kfree(acl);
+	return ret;
+}
+
+#endif /* CONFIG_BCACHEFS_POSIX_ACL */