bcachefs: allow initializing a bcachefs filesystem from a source directory

Add a new source command line argument which specifies the directory
tree that will be copied onto the newly formatted bcachefs filesystem.

This commit also fixes an issue in copy_link where uninitialized data is
copied into the symlink because of a round_up of the buffer size.

Signed-off-by: Ariel Miculas <ariel.miculas@gmail.com>
Signed-off-by: Kent Overstreet <kent.overstreet@linux.dev>

1 files changed, 460 insertions, 0 deletions

diff --git a/c_src/posix_to_bcachefs.c b/c_src/posix_to_bcachefs.c
new file mode 100644
index 00000000..e1460e9b
--- /dev/null
+++ b/c_src/posix_to_bcachefs.c
@@ -0,0 +1,460 @@
+#include <dirent.h>
+#include <sys/xattr.h>
+#include <linux/xattr.h>
+
+#include "posix_to_bcachefs.h"
+#include "libbcachefs/alloc_foreground.h"
+#include "libbcachefs/buckets.h"
+#include "libbcachefs/fs-common.h"
+#include "libbcachefs/io_write.h"
+#include "libbcachefs/str_hash.h"
+#include "libbcachefs/xattr.h"
+
+void update_inode(struct bch_fs *c,
+			 struct bch_inode_unpacked *inode)
+{
+	struct bkey_inode_buf packed;
+	int ret;
+
+	bch2_inode_pack(&packed, inode);
+	packed.inode.k.p.snapshot = U32_MAX;
+	ret = bch2_btree_insert(c, BTREE_ID_inodes, &packed.inode.k_i,
+				NULL, 0, 0);
+	if (ret)
+		die("error updating inode: %s", bch2_err_str(ret));
+}
+
+void create_link(struct bch_fs *c,
+			struct bch_inode_unpacked *parent,
+			const char *name, u64 inum, mode_t mode)
+{
+	struct qstr qstr = QSTR(name);
+	struct bch_inode_unpacked parent_u;
+	struct bch_inode_unpacked inode;
+
+	int ret = bch2_trans_do(c, NULL, NULL, 0,
+		bch2_link_trans(trans,
+				(subvol_inum) { 1, parent->bi_inum }, &parent_u,
+				(subvol_inum) { 1, inum }, &inode, &qstr));
+	if (ret)
+		die("error creating hardlink: %s", bch2_err_str(ret));
+}
+
+struct bch_inode_unpacked create_file(struct bch_fs *c,
+					     struct bch_inode_unpacked *parent,
+					     const char *name,
+					     uid_t uid, gid_t gid,
+					     mode_t mode, dev_t rdev)
+{
+	struct qstr qstr = QSTR(name);
+	struct bch_inode_unpacked new_inode;
+
+	bch2_inode_init_early(c, &new_inode);
+
+	int ret = bch2_trans_do(c, NULL, NULL, 0,
+		bch2_create_trans(trans,
+				  (subvol_inum) { 1, parent->bi_inum }, parent,
+				  &new_inode, &qstr,
+				  uid, gid, mode, rdev, NULL, NULL,
+				  (subvol_inum) {}, 0));
+	if (ret)
+		die("error creating %s: %s", name, bch2_err_str(ret));
+
+	return new_inode;
+}
+
+#define for_each_xattr_handler(handlers, handler)		\
+	if (handlers)						\
+		for ((handler) = *(handlers)++;			\
+			(handler) != NULL;			\
+			(handler) = *(handlers)++)
+
+static const struct xattr_handler *xattr_resolve_name(char **name)
+{
+	const struct xattr_handler **handlers = bch2_xattr_handlers;
+	const struct xattr_handler *handler;
+
+	for_each_xattr_handler(handlers, handler) {
+		char *n;
+
+		n = strcmp_prefix(*name, xattr_prefix(handler));
+		if (n) {
+			if (!handler->prefix ^ !*n) {
+				if (*n)
+					continue;
+				return ERR_PTR(-EINVAL);
+			}
+			*name = n;
+			return handler;
+		}
+	}
+	return ERR_PTR(-EOPNOTSUPP);
+}
+
+void copy_times(struct bch_fs *c, struct bch_inode_unpacked *dst,
+		       struct stat *src)
+{
+	dst->bi_atime = timespec_to_bch2_time(c, src->st_atim);
+	dst->bi_mtime = timespec_to_bch2_time(c, src->st_mtim);
+	dst->bi_ctime = timespec_to_bch2_time(c, src->st_ctim);
+}
+
+void copy_xattrs(struct bch_fs *c, struct bch_inode_unpacked *dst,
+			char *src)
+{
+	struct bch_hash_info hash_info = bch2_hash_info_init(c, dst);
+
+	char attrs[XATTR_LIST_MAX];
+	ssize_t attrs_size = llistxattr(src, attrs, sizeof(attrs));
+	if (attrs_size < 0)
+		die("listxattr error: %m");
+
+	char *next, *attr;
+	for (attr = attrs;
+	     attr < attrs + attrs_size;
+	     attr = next) {
+		next = attr + strlen(attr) + 1;
+
+		char val[XATTR_SIZE_MAX];
+		ssize_t val_size = lgetxattr(src, attr, val, sizeof(val));
+
+		if (val_size < 0)
+			die("error getting xattr val: %m");
+
+		const struct xattr_handler *h = xattr_resolve_name(&attr);
+		struct bch_inode_unpacked inode_u;
+
+		int ret = bch2_trans_do(c, NULL, NULL, 0,
+				bch2_xattr_set(trans,
+					       (subvol_inum) { 1, dst->bi_inum },
+					       &inode_u, &hash_info, attr,
+					       val, val_size, h->flags, 0));
+		if (ret < 0)
+			die("error creating xattr: %s", bch2_err_str(ret));
+	}
+}
+
+#define WRITE_DATA_BUF	(1 << 20)
+
+static char buf[WRITE_DATA_BUF] __aligned(PAGE_SIZE);
+
+static void write_data(struct bch_fs *c,
+		       struct bch_inode_unpacked *dst_inode,
+		       u64 dst_offset, void *buf, size_t len)
+{
+	struct bch_write_op op;
+	struct bio_vec bv[WRITE_DATA_BUF / PAGE_SIZE];
+
+	BUG_ON(dst_offset	& (block_bytes(c) - 1));
+	BUG_ON(len		& (block_bytes(c) - 1));
+	BUG_ON(len > WRITE_DATA_BUF);
+
+	bio_init(&op.wbio.bio, NULL, bv, ARRAY_SIZE(bv), 0);
+	bch2_bio_map(&op.wbio.bio, buf, len);
+
+	bch2_write_op_init(&op, c, bch2_opts_to_inode_opts(c->opts));
+	op.write_point	= writepoint_hashed(0);
+	op.nr_replicas	= 1;
+	op.subvol	= 1;
+	op.pos		= SPOS(dst_inode->bi_inum, dst_offset >> 9, U32_MAX);
+	op.flags |= BCH_WRITE_SYNC;
+
+	int ret = bch2_disk_reservation_get(c, &op.res, len >> 9,
+					    c->opts.data_replicas, 0);
+	if (ret)
+		die("error reserving space in new filesystem: %s", bch2_err_str(ret));
+
+	closure_call(&op.cl, bch2_write, NULL, NULL);
+
+	BUG_ON(!(op.flags & BCH_WRITE_DONE));
+	dst_inode->bi_sectors += len >> 9;
+
+	if (op.error)
+		die("write error: %s", bch2_err_str(op.error));
+}
+
+void copy_data(struct bch_fs *c,
+		      struct bch_inode_unpacked *dst_inode,
+		      int src_fd, u64 start, u64 end)
+{
+	while (start < end) {
+		unsigned len = min_t(u64, end - start, sizeof(buf));
+		unsigned pad = round_up(len, block_bytes(c)) - len;
+
+		xpread(src_fd, buf, len, start);
+		memset(buf + len, 0, pad);
+
+		write_data(c, dst_inode, start, buf, len + pad);
+		start += len;
+	}
+}
+
+static void link_data(struct bch_fs *c, struct bch_inode_unpacked *dst,
+		      u64 logical, u64 physical, u64 length)
+{
+	struct bch_dev *ca = c->devs[0];
+
+	BUG_ON(logical	& (block_bytes(c) - 1));
+	BUG_ON(physical & (block_bytes(c) - 1));
+	BUG_ON(length	& (block_bytes(c) - 1));
+
+	logical		>>= 9;
+	physical	>>= 9;
+	length		>>= 9;
+
+	BUG_ON(physical + length > bucket_to_sector(ca, ca->mi.nbuckets));
+
+	while (length) {
+		struct bkey_i_extent *e;
+		BKEY_PADDED_ONSTACK(k, BKEY_EXTENT_VAL_U64s_MAX) k;
+		u64 b = sector_to_bucket(ca, physical);
+		struct disk_reservation res;
+		unsigned sectors;
+		int ret;
+
+		sectors = min(ca->mi.bucket_size -
+			      (physical & (ca->mi.bucket_size - 1)),
+			      length);
+
+		e = bkey_extent_init(&k.k);
+		e->k.p.inode	= dst->bi_inum;
+		e->k.p.offset	= logical + sectors;
+		e->k.p.snapshot	= U32_MAX;
+		e->k.size	= sectors;
+		bch2_bkey_append_ptr(&e->k_i, (struct bch_extent_ptr) {
+					.offset = physical,
+					.dev = 0,
+					.gen = *bucket_gen(ca, b),
+				  });
+
+		ret = bch2_disk_reservation_get(c, &res, sectors, 1,
+						BCH_DISK_RESERVATION_NOFAIL);
+		if (ret)
+			die("error reserving space in new filesystem: %s",
+			    bch2_err_str(ret));
+
+		ret = bch2_btree_insert(c, BTREE_ID_extents, &e->k_i, &res, 0, 0);
+		if (ret)
+			die("btree insert error %s", bch2_err_str(ret));
+
+		bch2_disk_reservation_put(c, &res);
+
+		dst->bi_sectors	+= sectors;
+		logical		+= sectors;
+		physical	+= sectors;
+		length		-= sectors;
+	}
+}
+
+void copy_link(struct bch_fs *c, struct bch_inode_unpacked *dst,
+		      char *src)
+{
+	ssize_t i;
+	ssize_t ret = readlink(src, buf, sizeof(buf));
+	if (ret < 0)
+		die("readlink error: %m");
+
+	for (i = ret; i < round_up(ret, block_bytes(c)); i++)
+		buf[i] = 0;
+
+	write_data(c, dst, 0, buf, round_up(ret, block_bytes(c)));
+}
+
+static void copy_file(struct bch_fs *c, struct bch_inode_unpacked *dst,
+		      int src_fd, u64 src_size,
+		      char *src_path, struct copy_fs_state *s)
+{
+	struct fiemap_iter iter;
+	struct fiemap_extent e;
+
+	fiemap_for_each(src_fd, iter, e)
+		if (e.fe_flags & FIEMAP_EXTENT_UNKNOWN) {
+			fsync(src_fd);
+			break;
+		}
+	fiemap_iter_exit(&iter);
+
+	fiemap_for_each(src_fd, iter, e) {
+		u64 src_max = roundup(src_size, block_bytes(c));
+
+		e.fe_length = min(e.fe_length, src_max - e.fe_logical);
+
+		if ((e.fe_logical	& (block_bytes(c) - 1)) ||
+		    (e.fe_length	& (block_bytes(c) - 1)))
+			die("Unaligned extent in %s - can't handle", src_path);
+
+		if (COPY == s->type || (e.fe_flags & (FIEMAP_EXTENT_UNKNOWN|
+				  FIEMAP_EXTENT_ENCODED|
+				  FIEMAP_EXTENT_NOT_ALIGNED|
+				  FIEMAP_EXTENT_DATA_INLINE))) {
+			copy_data(c, dst, src_fd, e.fe_logical,
+				  min(src_size - e.fe_logical,
+				      e.fe_length));
+			continue;
+		}
+
+		/*
+		 * if the data is below 1 MB, copy it so it doesn't conflict
+		 * with bcachefs's potentially larger superblock:
+		 */
+		if (e.fe_physical < 1 << 20) {
+			copy_data(c, dst, src_fd, e.fe_logical,
+				  min(src_size - e.fe_logical,
+				      e.fe_length));
+			continue;
+		}
+
+		if ((e.fe_physical	& (block_bytes(c) - 1)))
+			die("Unaligned extent in %s - can't handle", src_path);
+
+		range_add(&s->extents, e.fe_physical, e.fe_length);
+		link_data(c, dst, e.fe_logical, e.fe_physical, e.fe_length);
+	}
+	fiemap_iter_exit(&iter);
+}
+
+static void copy_dir(struct copy_fs_state *s,
+		     struct bch_fs *c,
+		     struct bch_inode_unpacked *dst,
+		     int src_fd, const char *src_path)
+{
+	DIR *dir = fdopendir(src_fd);
+	struct dirent *d;
+
+	while ((errno = 0), (d = readdir(dir))) {
+		struct bch_inode_unpacked inode;
+		int fd;
+
+		if (fchdir(src_fd))
+			die("chdir error: %m");
+
+		struct stat stat =
+			xfstatat(src_fd, d->d_name, AT_SYMLINK_NOFOLLOW);
+
+		if (!strcmp(d->d_name, ".") ||
+		    !strcmp(d->d_name, "..") ||
+		    !strcmp(d->d_name, "lost+found"))
+			continue;
+
+		if (MIGRATE == s->type && stat.st_ino == s->bcachefs_inum)
+			continue;
+
+		char *child_path = mprintf("%s/%s", src_path, d->d_name);
+
+		if (s->type == MIGRATE && stat.st_dev != s->dev)
+			die("%s does not have correct st_dev!", child_path);
+
+		u64 *dst_inum = S_ISREG(stat.st_mode)
+			? genradix_ptr_alloc(&s->hardlinks, stat.st_ino, GFP_KERNEL)
+			: NULL;
+
+		if (dst_inum && *dst_inum) {
+			create_link(c, dst, d->d_name, *dst_inum, S_IFREG);
+			goto next;
+		}
+
+		inode = create_file(c, dst, d->d_name,
+				    stat.st_uid, stat.st_gid,
+				    stat.st_mode, stat.st_rdev);
+
+		if (dst_inum)
+			*dst_inum = inode.bi_inum;
+
+		copy_times(c, &inode, &stat);
+		copy_xattrs(c, &inode, d->d_name);
+
+		/* copy xattrs */
+
+		switch (mode_to_type(stat.st_mode)) {
+		case DT_DIR:
+			fd = xopen(d->d_name, O_RDONLY|O_NOATIME);
+			copy_dir(s, c, &inode, fd, child_path);
+			close(fd);
+			break;
+		case DT_REG:
+			inode.bi_size = stat.st_size;
+
+			fd = xopen(d->d_name, O_RDONLY|O_NOATIME);
+			copy_file(c, &inode, fd, stat.st_size,
+				  child_path, s);
+			close(fd);
+			break;
+		case DT_LNK:
+			inode.bi_size = stat.st_size;
+
+			copy_link(c, &inode, d->d_name);
+			break;
+		case DT_FIFO:
+		case DT_CHR:
+		case DT_BLK:
+		case DT_SOCK:
+		case DT_WHT:
+			/* nothing else to copy for these: */
+			break;
+		default:
+			BUG();
+		}
+
+		update_inode(c, &inode);
+next:
+		free(child_path);
+	}
+
+	if (errno)
+		die("readdir error: %m");
+	closedir(dir);
+}
+
+static void reserve_old_fs_space(struct bch_fs *c,
+				 struct bch_inode_unpacked *root_inode,
+				 ranges *extents)
+{
+	struct bch_dev *ca = c->devs[0];
+	struct bch_inode_unpacked dst;
+	struct hole_iter iter;
+	struct range i;
+
+	dst = create_file(c, root_inode, "old_migrated_filesystem",
+			  0, 0, S_IFREG|0400, 0);
+	dst.bi_size = bucket_to_sector(ca, ca->mi.nbuckets) << 9;
+
+	ranges_sort_merge(extents);
+
+	for_each_hole(iter, *extents, bucket_to_sector(ca, ca->mi.nbuckets) << 9, i)
+		link_data(c, &dst, i.start, i.start, i.end - i.start);
+
+	update_inode(c, &dst);
+}
+
+void copy_fs(struct bch_fs *c, int src_fd, const char *src_path,
+		    struct copy_fs_state *s)
+{
+	syncfs(src_fd);
+
+	struct bch_inode_unpacked root_inode;
+	int ret = bch2_inode_find_by_inum(c, (subvol_inum) { 1, BCACHEFS_ROOT_INO },
+					  &root_inode);
+	if (ret)
+		die("error looking up root directory: %s", bch2_err_str(ret));
+
+	if (fchdir(src_fd))
+		die("chdir error: %m");
+
+	struct stat stat = xfstat(src_fd);
+	copy_times(c, &root_inode, &stat);
+	copy_xattrs(c, &root_inode, ".");
+
+
+	/* now, copy: */
+	copy_dir(s, c, &root_inode, src_fd, src_path);
+
+	if (MIGRATE == s->type)
+		reserve_old_fs_space(c, &root_inode, &s->extents);
+
+	update_inode(c, &root_inode);
+
+	if (MIGRATE == s->type)
+		darray_exit(&s->extents);
+
+	genradix_free(&s->hardlinks);
+}