[PATCH v9 0/1] mkfs: add ability to populate filesystem from directory

[PATCH v9 0/1] mkfs: add ability to populate filesystem from directory

[Luca Di Maio]

Currently the only way to pre populate an XFS partition is via the
prototype file. While it works it has some limitations like:
  - not allowed spaces in file names
  - not preserving timestamps of original inodes

This series adds a new -P option to mkfs.xfs that allows users to
populate a newly created filesystem directly from an existing directory.
While similar to the prototype functionality, this doesn't require
writing a prototype file.
The implementation preserves file and directory attributes (ownership,
permissions, timestamps) from the source directory when copying content
to the new filesystem.

[v1] -> [v2]
  remove changes to protofile spec
  ensure backward compatibility
[v2] -> [v3]
  use inode_set_[acm]time() as suggested
  avoid copying atime and ctime
  they are often problematic for reproducibility, and
  mtime is the important information to preserve anyway
[v3] -> [v4]
  rewrite functionality to populate directly from an input directory
  this is similar to mkfs.ext4 option.
[v4] -> [v5]
  reorder patch to make it easier to review
  reflow to keep code below 80 chars
  use _() macro in prints
add SPDX headers to new files
  fix comment styling
  move from typedef to structs
  move direntry handling to own function
[v5] -> [v6]
  rebase on 6.14
[v6] -> [v7]
  move functionality to common -p flag
  add noatime flag to skip atime copy and set to current time
  set ctime/crtime to current time
  preserve hardlinks
  preserve extended attributes for all file/dir types
  add fsxattr to copied files/dirs
[v7] -> [v8]
  changed directory source validation to use stat() instead of open()
  changed hardlink tracker to store inode numbers instead of inode pointers
  fixed path buffer handling for directory traversal
  handle blocking FIFOs filetypes
  handle hardlinks of symlinks
  improve setup_proto and parse proto using structured xfs_proto_source type
  renamed noatime to preserve_atime with inverted logic
  specify EBADF fgetxattr() and flistxattr() fallback for O_PATH fds
  switch to calloc() to initialize hardlinks_tracker
  switch to reallocarray() for hardlinks_tracker resize
[v8] -> [v9]
  squash commits in one
  clarify the linear search implications in the commit log
  fixed indentation and styling
  fail early for invalid inputs
  pass dir fd along to reduce amount of open()
  switch from ino_t to xfs_ino_t
  add support for socket files
  copy fsxattr also for cases where we don't have an fd

Luca Di Maio (1):
  proto: add ability to populate a filesystem from a directory

 man/man8/mkfs.xfs.8.in |  41 ++-
 mkfs/proto.c           | 750 ++++++++++++++++++++++++++++++++++++++++-
 mkfs/proto.h           |  18 +-
 mkfs/xfs_mkfs.c        |  23 +-
 4 files changed, 806 insertions(+), 26 deletions(-)

--
2.49.0

[PATCH v9 1/1] proto: add ability to populate a filesystem from a directory

[Luca Di Maio]

This patch implements the functionality to populate a newly created XFS
filesystem directly from an existing directory structure.

It resuses existing protofile logic, it branches if input is a
directory.

The population process steps are as follows:
  - create the root inode before populating content
  - recursively process nested directories
  - handle regular files, directories, symlinks, char devices, block
    devices, sockets, fifos
  - preserve attributes (ownership, permissions)
  - preserve mtime timestamps from source files to maintain file history
    - use current time for atime/ctime/crtime
    - possible to specify atime=1 to preserve atime timestamps from
      source files
  - preserve extended attributes and fsxattrs for all file types
  - preserve hardlinks

At the moment, the implementation for the hardlink tracking is very
simple, as it involves a linear search.
from my local testing using larger source directories
(1.3mln inodes, ~400k hardlinks) the difference was actually
just a few seconds (given that most of the time is doing i/o).
We might want to revisit that in the future if this becomes a
bottleneck.

This functionality makes it easier to create populated filesystems
without having to mount them, it's particularly useful for
reproducible builds.

Signed-off-by: Luca Di Maio <luca.dimaio1@gmail.com>
---
 man/man8/mkfs.xfs.8.in |  41 ++-
 mkfs/proto.c           | 757 ++++++++++++++++++++++++++++++++++++++++-
 mkfs/proto.h           |  18 +-
 mkfs/xfs_mkfs.c        |  23 +-
 4 files changed, 813 insertions(+), 26 deletions(-)

diff --git a/man/man8/mkfs.xfs.8.in b/man/man8/mkfs.xfs.8.in
index 37e3a88e..bb38c148 100644
--- a/man/man8/mkfs.xfs.8.in
+++ b/man/man8/mkfs.xfs.8.in
@@ -28,7 +28,7 @@ mkfs.xfs \- construct an XFS filesystem
 .I naming_options
 ] [
 .B \-p
-.I protofile_options
+.I prototype_options
 ] [
 .B \-q
 ] [
@@ -977,30 +977,39 @@ option set.
 .PP
 .PD 0
 .TP
-.BI \-p " protofile_options"
+.BI \-p " prototype_options"
 .TP
 .BI "Section Name: " [proto]
 .PD
-These options specify the protofile parameters for populating the filesystem.
+These options specify the prototype parameters for populating the filesystem.
 The valid
-.I protofile_options
+.I prototype_options
 are:
 .RS 1.2i
 .TP
-.BI [file=] protofile
+.BI [file=]
 The
 .B file=
 prefix is not required for this CLI argument for legacy reasons.
 If specified as a config file directive, the prefix is required.
-
+.TP
+.BI [file=] directory
 If the optional
 .PD
-.I protofile
-argument is given,
+.I prototype
+argument is given, and it's a directory,
 .B mkfs.xfs
-uses
-.I protofile
-as a prototype file and takes its directions from that file.
+will populate the root file system with the contents of the given directory.
+Content, timestamps (atime, mtime), attributes and extended attributes are preserved
+for all file types.
+.TP
+.BI [file=] protofile
+If the optional
+.PD
+.I prototype
+argument is given, and points to a regular file,
+.B mkfs.xfs
+uses it as a prototype file and takes its directions from that file.
 The blocks and inodes specifiers in the
 .I protofile
 are provided for backwards compatibility, but are otherwise unused.
@@ -1136,8 +1145,16 @@ always terminated with the dollar (
 .B $
 ) token.
 .TP
+.BI atime= value
+If set to 1, when we're populating the root filesystem from a directory (
+.B file=directory
+option)
+access times are going to be preserved and are copied from the source files.
+Set to 0 to set access times to the current time instead.
+By default, this is set to 0.
+.TP
 .BI slashes_are_spaces= value
-If set to 1, slashes ("/") in the first token of each line of the protofile
+If set to 1, slashes ("/") in the first token of each line of the prototype file
 are converted to spaces.
 This enables the creation of a filesystem containing filenames with spaces.
 By default, this is set to 0.
diff --git a/mkfs/proto.c b/mkfs/proto.c
index 7f56a3d8..ffd580a2 100644
--- a/mkfs/proto.c
+++ b/mkfs/proto.c
@@ -5,6 +5,9 @@
  */
 
 #include "libxfs.h"
+#include <dirent.h>
+#include <fcntl.h>
+#include <sys/resource.h>
 #include <sys/stat.h>
 #include <sys/xattr.h>
 #include <linux/xattr.h>
@@ -21,6 +24,11 @@ static void rsvfile(xfs_mount_t *mp, xfs_inode_t *ip, long long len);
 static int newregfile(char **pp, char **fname);
 static void rtinit(xfs_mount_t *mp);
 static off_t filesize(int fd);
+static void populate_from_dir(struct xfs_mount *mp,
+				struct fsxattr *fsxp, char *source_dir);
+static void walk_dir(struct xfs_mount *mp, struct xfs_inode *pip,
+				struct fsxattr *fsxp, char *path_buf);
+static int preserve_atime;
 static int slashes_are_spaces;
 
 /*
@@ -54,7 +62,7 @@ getnum(
 	return i;
 }
 
-char *
+struct proto_source
 setup_proto(
 	char	*fname)
 {
@@ -63,8 +71,36 @@ setup_proto(
 	int		fd;
 	long		size;
 
-	if (!fname)
-		return dflt;
+	struct proto_source	result = {0};
+	struct stat	statbuf;
+
+	/*
+	 * for no input, use default root inode
+	 * this is actually a protofile, which
+	 * is valid.
+	 */
+	if (!fname) {
+		result.type = PROTO_SRC_PROTOFILE;
+		result.data = dflt;
+		return result;
+	}
+
+	if (stat(fname, &statbuf) < 0) {
+		fail(_("invalid or unreadable source path"), ENOENT);
+	}
+
+	/*
+	 * handle directory inputs
+	 */
+	if (S_ISDIR(statbuf.st_mode)) {
+		result.type = PROTO_SRC_DIR;
+		result.data = fname;
+		return result;
+	}
+
+	/*
+	 * else this is a protofile, let's handle traditionally
+	 */
 	if ((fd = open(fname, O_RDONLY)) < 0 || (size = filesize(fd)) < 0) {
 		fprintf(stderr, _("%s: failed to open %s: %s\n"),
 			progname, fname, strerror(errno));
@@ -90,7 +126,10 @@ setup_proto(
 	(void)getnum(getstr(&buf), 0, 0, false);	/* block count */
 	(void)getnum(getstr(&buf), 0, 0, false);	/* inode count */
 	close(fd);
-	return buf;
+
+	result.type = PROTO_SRC_PROTOFILE;
+	result.data = buf;
+	return result;
 
 out_fail:
 	if (fd >= 0)
@@ -379,11 +418,19 @@ writeattr(
 	int			error;
 
 	ret = fgetxattr(fd, attrname, valuebuf, valuelen);
+	/*
+	 * in case of filedescriptors with O_PATH, fgetxattr() will
+	 * fail with EBADF. let's try to fallback to lgetxattr() using input
+	 * path.
+	 */
+	if (ret < 0 && errno == EBADF)
+		ret = lgetxattr(fname, attrname, valuebuf, valuelen);
 	if (ret < 0) {
 		if (errno == EOPNOTSUPP)
 			return;
 		fail(_("error collecting xattr value"), errno);
 	}
+
 	if (ret == 0)
 		return;
 
@@ -425,6 +472,13 @@ writeattrs(
 		fail(_("error allocating xattr name buffer"), errno);
 
 	ret = flistxattr(fd, namebuf, XATTR_LIST_MAX);
+	/*
+	 * in case of filedescriptors with O_PATH, flistxattr() will
+	 * fail with EBADF. let's try to fallback to llistxattr() using input
+	 * path.
+	 */
+	if (ret < 0 && errno == EBADF)
+		ret = llistxattr(fname, namebuf, XATTR_LIST_MAX);
 	if (ret < 0) {
 		if (errno == EOPNOTSUPP)
 			goto out_namebuf;
@@ -933,11 +987,27 @@ void
 parse_proto(
 	xfs_mount_t	*mp,
 	struct fsxattr	*fsx,
-	char		**pp,
-	int		proto_slashes_are_spaces)
+	struct proto_source	*protosource,
+	int		proto_slashes_are_spaces,
+	int		proto_preserve_atime)
 {
 	slashes_are_spaces = proto_slashes_are_spaces;
-	parseproto(mp, NULL, fsx, pp, NULL);
+	preserve_atime = proto_preserve_atime;
+
+	/*
+	 * in case of a file input, we will use the prototype file logic
+	 * else we will fallback to populate from dir.
+	 */
+	switch(protosource->type) {
+	case PROTO_SRC_PROTOFILE:
+		parseproto(mp, NULL, fsx, &protosource->data, NULL);
+		break;
+	case PROTO_SRC_DIR:
+		populate_from_dir(mp, fsx, protosource->data);
+		break;
+	case PROTO_SRC_NONE:
+		fail(_("invalid or unreadable source path"), ENOENT);
+	}
 }
 
 /* Create a sb-rooted metadata file. */
@@ -1171,3 +1241,676 @@ filesize(
 		return -1;
 	return stb.st_size;
 }
+
+/* Try to allow as many memfds as possible. */
+static void
+bump_max_fds(void)
+{
+	struct rlimit	rlim = {};
+	int ret;
+
+	ret = getrlimit(RLIMIT_NOFILE, &rlim);
+	if (ret)
+		return;
+
+	rlim.rlim_cur = rlim.rlim_max;
+	ret = setrlimit(RLIMIT_NOFILE, &rlim);
+	if (ret < 0)
+		fprintf(stderr, _("%s: could not bump fd limit: [ %d - %s]\n"),
+				progname, errno, strerror(errno));
+}
+
+static void
+writefsxattrs(
+	struct xfs_inode	*ip,
+	struct fsxattr		*fsxp)
+{
+	ip->i_projid = fsxp->fsx_projid;
+	ip->i_extsize = fsxp->fsx_extsize;
+	ip->i_diflags = xfs_flags2diflags(ip, fsxp->fsx_xflags);
+	if (xfs_has_v3inodes(ip->i_mount)) {
+		ip->i_diflags2 = xfs_flags2diflags2(ip, fsxp->fsx_xflags);
+		ip->i_cowextsize = fsxp->fsx_cowextsize;
+	}
+}
+
+static void
+writetimestamps(
+	struct xfs_inode	*ip,
+	struct stat	statbuf)
+{
+	struct timespec64	ts;
+
+	/*
+	 * Copy timestamps from source file to destination inode.
+	 * Usually reproducible archives will delete or not register
+	 * atime and ctime, for example:
+	 *    https://www.gnu.org/software/tar/manual/html_section/Reproducibility.html
+	 * hence we will only copy mtime, and let ctime/crtime be set to
+	 * current time.
+	 * atime will be copied over if atime is true.
+	 */
+	ts.tv_sec = statbuf.st_mtim.tv_sec;
+	ts.tv_nsec = statbuf.st_mtim.tv_nsec;
+	inode_set_mtime_to_ts(VFS_I(ip), ts);
+
+	/*
+	 * in case of atime option, we will copy the atime
+	 * timestamp from source.
+	 */
+	if (preserve_atime) {
+		ts.tv_sec = statbuf.st_atim.tv_sec;
+		ts.tv_nsec = statbuf.st_atim.tv_nsec;
+		inode_set_atime_to_ts(VFS_I(ip), ts);
+	}
+}
+
+struct hardlink {
+	xfs_ino_t	src_ino;
+	xfs_ino_t	dst_ino;
+};
+
+struct hardlinks {
+	size_t		count;
+	size_t		size;
+	struct hardlink	*entries;
+};
+
+/* Growth strategy for hardlink tracking array */
+#define HARDLINK_DEFAULT_GROWTH_FACTOR	2		/* Double size for small arrays */
+#define HARDLINK_LARGE_GROWTH_FACTOR	0.25	/* Grow by 25% for large arrays */
+#define HARDLINK_THRESHOLD				1024	/* Threshold to switch growth strategies */
+#define HARDLINK_TRACKER_INITIAL_SIZE	4096	/* Initial allocation size */
+
+/*
+ * keep track of source inodes that are from hardlinks
+ * so we can retrieve them when needed to setup in
+ * destination.
+ */
+static struct hardlinks *hardlink_tracker = { 0 };
+
+static void
+init_hardlink_tracker(void)
+{
+	hardlink_tracker = calloc(1, sizeof(struct hardlinks));
+	if (!hardlink_tracker)
+		fail(_("error allocating hardlinks tracking array"), errno);
+
+	hardlink_tracker->size = HARDLINK_TRACKER_INITIAL_SIZE;
+	hardlink_tracker->entries = calloc(
+			hardlink_tracker->size,
+			sizeof(struct hardlink));
+	if (!hardlink_tracker->entries)
+		fail(_("error allocating hardlinks tracking array"), errno);
+}
+
+static void
+cleanup_hardlink_tracker(void)
+{
+	free(hardlink_tracker->entries);
+	free(hardlink_tracker);
+	hardlink_tracker = NULL;
+}
+
+static xfs_ino_t
+get_hardlink_dst_inode(
+	xfs_ino_t i_ino)
+{
+	for (size_t i = 0; i < hardlink_tracker->count; i++) {
+		if (hardlink_tracker->entries[i].src_ino == i_ino) {
+			return hardlink_tracker->entries[i].dst_ino;
+		}
+	}
+	return 0;
+}
+
+static void
+track_hardlink_inode(
+	xfs_ino_t src_ino,
+	xfs_ino_t dst_ino)
+{
+	if (hardlink_tracker->count >= hardlink_tracker->size) {
+		/*
+		 * double for smaller capacity.
+		 * instead grow by 25% steps for larger capacities.
+		 */
+		const size_t old_size = hardlink_tracker->size;
+		size_t new_size = old_size * HARDLINK_DEFAULT_GROWTH_FACTOR;
+		if (old_size > HARDLINK_THRESHOLD)
+			new_size = old_size + (old_size * HARDLINK_LARGE_GROWTH_FACTOR);
+
+		struct hardlink *resized_array = reallocarray(
+			hardlink_tracker->entries,
+			new_size,
+			sizeof(struct hardlink));
+		if (!resized_array)
+			fail(_("error enlarging hardlinks tracking array"), errno);
+
+		memset(&resized_array[old_size], 0,
+				(new_size - old_size) * sizeof(struct hardlink));
+
+		hardlink_tracker->entries = resized_array;
+		hardlink_tracker->size = new_size;
+	}
+
+	hardlink_tracker->entries[hardlink_tracker->count].src_ino = src_ino;
+	hardlink_tracker->entries[hardlink_tracker->count].dst_ino = dst_ino;
+	hardlink_tracker->count++;
+}
+
+/*
+ * this function will first check in our tracker if
+ * the input hardlink has already been stored, if not
+ * report false so create_file() can continue handling
+ * the inode as a regular file type, and later save
+ * the source inode in our buffer for future consumption.
+ */
+static bool
+handle_hardlink(
+	struct xfs_mount	*mp,
+	struct xfs_inode	*pip,
+	struct xfs_name	xname,
+	struct stat	file_stat)
+{
+	int error;
+	struct xfs_inode	*ip;
+	struct xfs_trans	*tp;
+	struct xfs_parent_args *ppargs = NULL;
+	tp = getres(mp, 0);
+	ppargs = newpptr(mp);
+
+	xfs_ino_t dst_ino = get_hardlink_dst_inode(file_stat.st_ino);
+	/*
+	 * we didn't find the hardlink inode, this means
+	 * it's the first time we see it, report error
+	 * so create_file() can continue handling the inode
+	 * as a regular file type, and later save
+	 * the source inode in our buffer for future consumption.
+	 */
+	if (dst_ino == 0)
+		return false;
+
+	error = libxfs_iget(mp, NULL, dst_ino, 0, &ip);
+	if (error) {
+		fprintf(stderr, _("failed to iget inode %lu\n"), dst_ino);
+		exit(1);
+	}
+
+	/*
+	* In case the inode was already in our tracker
+	* we need to setup the hardlink and skip file
+	* copy.
+	*/
+	libxfs_trans_ijoin(tp, pip, 0);
+	libxfs_trans_ijoin(tp, ip, 0);
+	newdirent(mp, tp, pip, &xname, ip, ppargs);
+
+	/*
+	 * Increment the link count
+	 */
+	libxfs_bumplink(tp, ip);
+
+	libxfs_trans_log_inode(tp, ip, XFS_ILOG_CORE);
+
+	error = -libxfs_trans_commit(tp);
+	if (error)
+		fail(_("Error encountered creating file from prototype file"), error);
+
+	libxfs_parent_finish(mp, ppargs);
+	libxfs_irele(ip);
+
+	return true;
+}
+
+static void
+create_file(
+	struct xfs_mount	*mp,
+	struct xfs_inode	*pip,
+	struct fsxattr	*fsxp,
+	int mode,
+	struct cred	creds,
+	struct xfs_name	xname,
+	int flags,
+	struct stat	file_stat,
+	xfs_dev_t rdev,
+	int fd,
+	char *fname)
+{
+
+	int error;
+	struct xfs_inode	*ip;
+	struct xfs_trans	*tp;
+	struct xfs_parent_args *ppargs = NULL;
+
+	/*
+	* if handle_hardlink() returns true it means the hardlink has
+	* been correctly found and set, so we don't need to
+	* do anything else.
+	*/
+	if (file_stat.st_nlink > 1 && handle_hardlink(mp, pip, xname, file_stat)) {
+		close(fd);
+		return;
+	}
+	/*
+	 * if instead we have an error it means the hardlink
+	 * was not registered, so we proceed to treat it like
+	 * a regular file, and save it to our tracker later.
+	 */
+	tp = getres(mp, 0);
+	ppargs = newpptr(mp);
+
+	error = creatproto(&tp, pip, mode, rdev, &creds, fsxp, &ip);
+	if (error)
+		fail(_("Inode allocation failed"), error);
+
+	libxfs_trans_ijoin(tp, pip, 0);
+	newdirent(mp, tp, pip, &xname, ip, ppargs);
+
+	/*
+	 * copy over timestamps
+	 */
+	writetimestamps(ip, file_stat);
+
+	libxfs_trans_log_inode(tp, ip, flags);
+
+	error = -libxfs_trans_commit(tp);
+	if (error)
+		fail(_("Error encountered creating file from prototype file"), error);
+
+	libxfs_parent_finish(mp, ppargs);
+
+	/*
+	 * copy over file content, attributes,
+	 * extended attributes and timestamps
+	 *
+	 * hardlinks will be skipped as fd will
+	 * be closed before this.
+	 */
+	if (fd >= 0) {
+		writefile(ip, fname, fd);
+		writeattrs(ip, fname, fd);
+		close(fd);
+	}
+	/*
+	 * we do fsxattr also for file types where we don't have
+	 * an fd, for example FIFOs
+	 */
+	writefsxattrs(ip, fsxp);
+
+	/*
+	 * if we're here it means this is the first time we're
+	 * encountering an hardlink, so we need to store it
+	 */
+	if (file_stat.st_nlink > 1)
+		track_hardlink_inode(file_stat.st_ino, ip->i_ino);
+
+	libxfs_irele(ip);
+}
+
+static void
+handle_direntry(
+	struct xfs_mount	*mp,
+	struct xfs_inode	*pip,
+	struct fsxattr	*fsxp,
+	char *path_buf,
+	struct dirent	*entry)
+{
+	char link_target[PATH_MAX];
+	int error;
+	int fd = -1;
+	int flags;
+	int majdev;
+	int mindev;
+	int mode;
+	struct stat	file_stat;
+	struct xfs_name	xname;
+	struct xfs_inode	*ip;
+	struct xfs_trans	*tp;
+	struct xfs_parent_args *ppargs = NULL;
+
+	/*
+	 * save original path length so we can
+	 * restore the original value at the end
+	 * of the function
+	 */
+	size_t path_save_len = strlen(path_buf);
+	size_t path_len = path_save_len;
+	size_t entry_len = strlen(entry->d_name);
+
+	/*
+	 * ensure the constructed path is within PATH_MAX limits
+	 */
+	size_t remaining = PATH_MAX - path_len;
+	size_t written = snprintf(path_buf + path_len, remaining, "/%s",
+			entry->d_name);
+	if (written >= remaining) {
+		fail(_("path name too long"), ENAMETOOLONG);
+	}
+
+	if (lstat(path_buf, &file_stat) < 0) {
+		fprintf(stderr, _("%s: cannot stat '%s': %s (errno=%d)\n"),
+				progname, path_buf, strerror(errno), errno);
+		exit(1);
+	}
+
+	/*
+	 * avoid opening FIFOs as they're blocking
+	 */
+	int open_flags = O_NOFOLLOW | O_RDONLY | O_NOATIME;
+	/*
+	* symlinks and sockets will need to be opened with O_PATH to work,
+	* so we handle this special case.
+	*/
+	if (S_ISSOCK(file_stat.st_mode)
+			|| S_ISLNK(file_stat.st_mode)
+			|| S_ISFIFO(file_stat.st_mode))
+		open_flags = O_NOFOLLOW | O_PATH;
+	if ((fd = open(path_buf, open_flags)) < 0) {
+		fprintf(stderr, _("%s: cannot open %s: %s\n"), progname, path_buf,
+			strerror(errno));
+		exit(1);
+	}
+
+	struct cred creds = {
+		.cr_uid = file_stat.st_uid,
+		.cr_gid = file_stat.st_gid,
+	};
+
+	xname.name = (unsigned char *)entry->d_name;
+	xname.len = entry_len;
+	xname.type = 0;
+	mode = file_stat.st_mode;
+	flags = XFS_ILOG_CORE;
+
+	switch (file_stat.st_mode & S_IFMT) {
+	case S_IFDIR:
+		tp = getres(mp, 0);
+		ppargs = newpptr(mp);
+
+		error = creatproto(&tp, pip, mode, 0, &creds, fsxp, &ip);
+		if (error)
+			fail(_("Inode allocation failed"), error);
+
+		libxfs_trans_ijoin(tp, pip, 0);
+
+		xname.type = XFS_DIR3_FT_DIR;
+		newdirent(mp, tp, pip, &xname, ip, ppargs);
+
+		libxfs_bumplink(tp, pip);
+		libxfs_trans_log_inode(tp, pip, XFS_ILOG_CORE);
+		newdirectory(mp, tp, ip, pip);
+
+		/*
+		 * copy over timestamps
+		 */
+		writetimestamps(ip, file_stat);
+
+		libxfs_trans_log_inode(tp, ip, flags);
+
+		error = -libxfs_trans_commit(tp);
+		if (error)
+			fail(_("Directory inode allocation failed."), error);
+
+		libxfs_parent_finish(mp, ppargs);
+		tp = NULL;
+
+		/*
+		 * copy over attributes
+		 */
+		writeattrs(ip, entry->d_name, fd);
+		writefsxattrs(ip, fsxp);
+		close(fd);
+
+		walk_dir(mp, ip, fsxp, path_buf);
+
+		libxfs_irele(ip);
+		break;
+	case S_IFLNK:
+		/*
+		* if handle_hardlink() returns true it means the hardlink has
+		* been correctly found and set, so we don't need to
+		* do anything else.
+		*/
+		if (file_stat.st_nlink > 1 &&
+				handle_hardlink(mp, pip, xname, file_stat)) {
+			close(fd);
+			break;
+		}
+		/*
+		* if instead we have false it means the hardlink
+		* was not registered, so we proceed to treat it like
+		* a regular symlink, and save it to our tracker later.
+		*/
+		ssize_t len = readlink(path_buf, link_target, PATH_MAX - 1);
+		if (len < 0)
+			fail(_("could not resolve symlink"), errno);
+		if (len >= PATH_MAX -1)
+			fail(_("symlink target too long"), ENAMETOOLONG);
+		link_target[len] = '\0';
+
+		tp = getres(mp, XFS_B_TO_FSB(mp, len));
+		ppargs = newpptr(mp);
+
+		error = creatproto(&tp, pip, mode, 0, &creds, fsxp, &ip);
+		if (error)
+			fail(_("Inode allocation failed"), error);
+
+		writesymlink(tp, ip, link_target, len);
+		libxfs_trans_ijoin(tp, pip, 0);
+
+		xname.type = XFS_DIR3_FT_SYMLINK;
+		newdirent(mp, tp, pip, &xname, ip, ppargs);
+
+		/*
+		 * copy over timestamps
+		 */
+		writetimestamps(ip, file_stat);
+
+		libxfs_trans_log_inode(tp, ip, flags);
+
+		error = -libxfs_trans_commit(tp);
+		if (error)
+			fail(_("Error encountered creating file from prototype file"),
+			     error);
+
+		libxfs_parent_finish(mp, ppargs);
+
+		/*
+		 * copy over attributes
+		 *
+		 * being a symlink we opened the filedescriptor with O_PATH
+		 * this will make flistxattr() and fgetxattr() fail wil EBADF,
+		 * so we  will need to fallback to llistxattr() and lgetxattr(),
+		 * this will need the full path to the original file, not just the
+		 * entry name.
+		 */
+		writeattrs(ip, path_buf, fd);
+		writefsxattrs(ip, fsxp);
+		close(fd);
+
+		/*
+		 * if we're here it means this is the first time we're
+		 * encountering an hardlink, so we need to store it
+		 */
+		if (file_stat.st_nlink > 1)
+			track_hardlink_inode(file_stat.st_ino, ip->i_ino);
+
+		libxfs_irele(ip);
+		break;
+	case S_IFREG:
+		xname.type = XFS_DIR3_FT_REG_FILE;
+		create_file(mp, pip, fsxp, mode, creds, xname, flags, file_stat,
+			    0, fd, entry->d_name);
+		break;
+	case S_IFCHR:
+		xname.type = XFS_DIR3_FT_CHRDEV;
+		majdev = major(file_stat.st_rdev);
+		mindev = minor(file_stat.st_rdev);
+		create_file(mp, pip, fsxp, mode, creds, xname, flags, file_stat,
+			    IRIX_MKDEV(majdev, mindev), fd, entry->d_name);
+		break;
+	case S_IFBLK:
+		xname.type = XFS_DIR3_FT_BLKDEV;
+		majdev = major(file_stat.st_rdev);
+		mindev = minor(file_stat.st_rdev);
+		create_file(mp, pip, fsxp, mode, creds, xname, flags, file_stat,
+			    IRIX_MKDEV(majdev, mindev), fd, entry->d_name);
+		break;
+	case S_IFIFO:
+		flags |= XFS_ILOG_DEV;
+		/*
+		 * being a fifo we opened the filedescriptor with O_PATH
+		 * this will make flistxattr() and fgetxattr() fail wil EBADF,
+		 * so we  will need to fallback to llistxattr() and lgetxattr(),
+		 * this will need the full path to the original file, not just the
+		 * entry name.
+		 */
+		create_file(mp, pip, fsxp, mode, creds, xname, flags, file_stat,
+			    0, fd, path_buf);
+		break;
+	case S_IFSOCK:
+		flags |= XFS_ILOG_DEV;
+		/*
+		 * being a socket we opened the filedescriptor with O_PATH
+		 * this will make flistxattr() and fgetxattr() fail wil EBADF,
+		 * so we  will need to fallback to llistxattr() and lgetxattr(),
+		 * this will need the full path to the original file, not just the
+		 * entry name.
+		 */
+		create_file(mp, pip, fsxp, mode, creds, xname, flags, file_stat,
+			    0, fd, path_buf);
+		break;
+	default:
+		break;
+	}
+
+	/*
+	 * restore path buffer to original length before returning
+	 * */
+	path_buf[path_save_len] = '\0';
+}
+
+/*
+ * walk_dir will recursively list files and directories
+ * and populate the mountpoint *mp with them using handle_direntry().
+ */
+static void
+walk_dir(
+	struct xfs_mount	*mp,
+	struct xfs_inode	*pip,
+	struct fsxattr	*fsxp,
+	char *path_buf)
+{
+	DIR *dir;
+	struct dirent	*entry;
+
+	/*
+	 * open input directory and iterate over all entries in it.
+	 * when another directory is found, we will recursively call
+	 * walk_dir.
+	 */
+	if ((dir = opendir(path_buf)) == NULL) {
+		fprintf(stderr, _("%s: cannot open input dir: %s [%d - %s]\n"),
+				progname, path_buf, errno, strerror(errno));
+		exit(1);
+	}
+	while ((entry = readdir(dir)) != NULL) {
+		if (strcmp(entry->d_name, ".") == 0 ||
+				strcmp(entry->d_name, "..") == 0) {
+			continue;
+		}
+
+		handle_direntry(mp, pip, fsxp, path_buf, entry);
+	}
+	closedir(dir);
+}
+
+static void
+populate_from_dir(
+	struct xfs_mount	*mp,
+	struct fsxattr	*fsxp,
+	char	*cur_path)
+{
+	int error;
+	int mode;
+	struct xfs_inode	*ip;
+	struct xfs_trans	*tp;
+
+	char			path_buf[PATH_MAX];
+
+	/*
+	 * initialize path_buf cur_path, strip trailing slashes
+	 * they're automatically added when walking the dir
+	 */
+	if (strlen(cur_path) > 1 && cur_path[strlen(cur_path)-1] == '/')
+		cur_path[strlen(cur_path)-1] = '\0';
+	if (snprintf(path_buf, PATH_MAX, "%s", cur_path) >= PATH_MAX)
+		fail(_("path name too long"), ENAMETOOLONG);
+
+	/*
+	 * we first ensure we have the root inode
+	 */
+	struct cred creds = {
+		.cr_uid = 0,
+		.cr_gid = 0,
+
+	};
+	mode = S_IRWXU | S_IRGRP | S_IXGRP | S_IROTH | S_IXOTH;
+
+	tp = getres(mp, 0);
+
+	error = creatproto(&tp, NULL, mode | S_IFDIR, 0, &creds, fsxp, &ip);
+	if (error)
+		fail(_("Inode allocation failed"), error);
+
+	mp->m_sb.sb_rootino = ip->i_ino;
+	libxfs_log_sb(tp);
+	newdirectory(mp, tp, ip, ip);
+	libxfs_trans_log_inode(tp, ip, XFS_ILOG_CORE);
+
+	error = -libxfs_trans_commit(tp);
+	if (error)
+		fail(_("Inode allocation failed"), error);
+
+	libxfs_parent_finish(mp, NULL);
+
+	/*
+	 * RT initialization.  Do this here to ensure that
+	 * the RT inodes get placed after the root inode.
+	 */
+	error = create_metadir(mp);
+	if (error)
+		fail(_("Creation of the metadata directory inode failed"), error);
+
+	rtinit(mp);
+
+	/*
+	 * by nature of walk_dir() we could be opening
+	 * a great number of fds for deeply nested directory
+	 * trees.
+	 * try to bump max fds limit.
+	 */
+	bump_max_fds();
+
+	/*
+	 * initialize the hardlinks tracker
+	 */
+	init_hardlink_tracker();
+	/*
+	 * now that we have a root inode, let's
+	 * walk the input dir and populate the partition
+	 */
+	walk_dir(mp, ip, fsxp, path_buf);
+
+	/*
+	 * cleanup hardlinks tracker
+	 */
+	cleanup_hardlink_tracker();
+
+	/*
+	 * we free up our root inode
+	 * only when we finished populating the
+	 * root filesystem
+	 */
+	libxfs_irele(ip);
+}
diff --git a/mkfs/proto.h b/mkfs/proto.h
index be1ceb45..476f7851 100644
--- a/mkfs/proto.h
+++ b/mkfs/proto.h
@@ -6,9 +6,21 @@
 #ifndef MKFS_PROTO_H_
 #define MKFS_PROTO_H_
 
-char *setup_proto(char *fname);
-void parse_proto(struct xfs_mount *mp, struct fsxattr *fsx, char **pp,
-		int proto_slashes_are_spaces);
+enum proto_source_type {
+	PROTO_SRC_NONE = 0,
+	PROTO_SRC_PROTOFILE,
+	PROTO_SRC_DIR
+};
+struct proto_source {
+	enum	proto_source_type type;
+	char	*data;
+};
+
+struct proto_source setup_proto(char *fname);
+void parse_proto(struct xfs_mount *mp, struct fsxattr *fsx,
+		 struct proto_source *protosource,
+		 int proto_slashes_are_spaces,
+		 int proto_preserve_atime);
 void res_failed(int err);
 
 #endif /* MKFS_PROTO_H_ */
diff --git a/mkfs/xfs_mkfs.c b/mkfs/xfs_mkfs.c
index 3f4455d4..a32c077e 100644
--- a/mkfs/xfs_mkfs.c
+++ b/mkfs/xfs_mkfs.c
@@ -121,6 +121,7 @@ enum {
 
 enum {
 	P_FILE = 0,
+	P_ATIME,
 	P_SLASHES,
 	P_MAX_OPTS,
 };
@@ -709,6 +710,7 @@ static struct opt_params popts = {
 	.ini_section = "proto",
 	.subopts = {
 		[P_FILE] = "file",
+		[P_ATIME] = "atime",
 		[P_SLASHES] = "slashes_are_spaces",
 		[P_MAX_OPTS] = NULL,
 	},
@@ -717,6 +719,12 @@ static struct opt_params popts = {
 		  .conflicts = { { NULL, LAST_CONFLICT } },
 		  .defaultval = SUBOPT_NEEDS_VAL,
 		},
+		{ .index = P_ATIME,
+		  .conflicts = { { NULL, LAST_CONFLICT } },
+		  .minval = 0,
+		  .maxval = 1,
+		  .defaultval = 1,
+		},
 		{ .index = P_SLASHES,
 		  .conflicts = { { NULL, LAST_CONFLICT } },
 		  .minval = 0,
@@ -1045,6 +1053,7 @@ struct cli_params {
 	int	lsunit;
 	int	is_supported;
 	int	proto_slashes_are_spaces;
+	int	proto_atime;
 	int	data_concurrency;
 	int	log_concurrency;
 	int	rtvol_concurrency;
@@ -1170,6 +1179,7 @@ usage( void )
 /* naming */		[-n size=num,version=2|ci,ftype=0|1,parent=0|1]]\n\
 /* no-op info only */	[-N]\n\
 /* prototype file */	[-p fname]\n\
+/* populate from directory */	[-p dirname,atime=0|1]\n\
 /* quiet */		[-q]\n\
 /* realtime subvol */	[-r extsize=num,size=num,rtdev=xxx,rgcount=n,rgsize=n,\n\
 			    concurrency=num]\n\
@@ -2067,6 +2077,9 @@ proto_opts_parser(
 	case P_SLASHES:
 		cli->proto_slashes_are_spaces = getnum(value, opts, subopt);
 		break;
+	case P_ATIME:
+		cli->proto_atime = getnum(value, opts, subopt);
+		break;
 	case P_FILE:
 		fallthrough;
 	default:
@@ -5162,7 +5175,7 @@ main(
 	int			discard = 1;
 	int			force_overwrite = 0;
 	int			quiet = 0;
-	char			*protostring = NULL;
+	struct proto_source	protosource;
 	int			worst_freelist = 0;
 
 	struct libxfs_init	xi = {
@@ -5311,8 +5324,6 @@ main(
 	 */
 	cfgfile_parse(&cli);
 
-	protostring = setup_proto(cli.protofile);
-
 	/*
 	 * Extract as much of the valid config as we can from the CLI input
 	 * before opening the libxfs devices.
@@ -5480,7 +5491,11 @@ main(
 	/*
 	 * Allocate the root inode and anything else in the proto file.
 	 */
-	parse_proto(mp, &cli.fsx, &protostring, cli.proto_slashes_are_spaces);
+	protosource = setup_proto(cli.protofile);
+	parse_proto(mp, &cli.fsx,
+			&protosource,
+			cli.proto_slashes_are_spaces,
+			cli.proto_atime);
 
 	/*
 	 * Protect ourselves against possible stupidity
-- 
2.49.0

Re: [PATCH v9 1/1] proto: add ability to populate a filesystem from a directory

[Darrick J. Wong]

On Wed, May 07, 2025 at 06:48:52PM +0200, Luca Di Maio wrote:
> This patch implements the functionality to populate a newly created XFS
> filesystem directly from an existing directory structure.
> 
> It resuses existing protofile logic, it branches if input is a
> directory.
> 
> The population process steps are as follows:
>   - create the root inode before populating content
>   - recursively process nested directories
>   - handle regular files, directories, symlinks, char devices, block
>     devices, sockets, fifos
>   - preserve attributes (ownership, permissions)
>   - preserve mtime timestamps from source files to maintain file history
>     - use current time for atime/ctime/crtime
>     - possible to specify atime=1 to preserve atime timestamps from
>       source files
>   - preserve extended attributes and fsxattrs for all file types
>   - preserve hardlinks
> 
> At the moment, the implementation for the hardlink tracking is very
> simple, as it involves a linear search.
> from my local testing using larger source directories
> (1.3mln inodes, ~400k hardlinks) the difference was actually
> just a few seconds (given that most of the time is doing i/o).
> We might want to revisit that in the future if this becomes a
> bottleneck.
> 
> This functionality makes it easier to create populated filesystems
> without having to mount them, it's particularly useful for
> reproducible builds.
> 
> Signed-off-by: Luca Di Maio <luca.dimaio1@gmail.com>
> ---
>  man/man8/mkfs.xfs.8.in |  41 ++-
>  mkfs/proto.c           | 757 ++++++++++++++++++++++++++++++++++++++++-
>  mkfs/proto.h           |  18 +-
>  mkfs/xfs_mkfs.c        |  23 +-
>  4 files changed, 813 insertions(+), 26 deletions(-)
> 
> diff --git a/man/man8/mkfs.xfs.8.in b/man/man8/mkfs.xfs.8.in
> index 37e3a88e..bb38c148 100644
> --- a/man/man8/mkfs.xfs.8.in
> +++ b/man/man8/mkfs.xfs.8.in
> @@ -28,7 +28,7 @@ mkfs.xfs \- construct an XFS filesystem
>  .I naming_options
>  ] [
>  .B \-p
> -.I protofile_options
> +.I prototype_options
>  ] [
>  .B \-q
>  ] [
> @@ -977,30 +977,39 @@ option set.
>  .PP
>  .PD 0
>  .TP
> -.BI \-p " protofile_options"
> +.BI \-p " prototype_options"
>  .TP
>  .BI "Section Name: " [proto]
>  .PD
> -These options specify the protofile parameters for populating the filesystem.
> +These options specify the prototype parameters for populating the filesystem.
>  The valid
> -.I protofile_options
> +.I prototype_options
>  are:
>  .RS 1.2i
>  .TP
> -.BI [file=] protofile
> +.BI [file=]
>  The
>  .B file=
>  prefix is not required for this CLI argument for legacy reasons.
>  If specified as a config file directive, the prefix is required.
> -
> +.TP
> +.BI [file=] directory
>  If the optional
>  .PD
> -.I protofile
> -argument is given,
> +.I prototype
> +argument is given, and it's a directory,
>  .B mkfs.xfs
> -uses
> -.I protofile
> -as a prototype file and takes its directions from that file.
> +will populate the root file system with the contents of the given directory.
> +Content, timestamps (atime, mtime), attributes and extended attributes are preserved
> +for all file types.
> +.TP
> +.BI [file=] protofile
> +If the optional
> +.PD
> +.I prototype
> +argument is given, and points to a regular file,
> +.B mkfs.xfs
> +uses it as a prototype file and takes its directions from that file.
>  The blocks and inodes specifiers in the
>  .I protofile
>  are provided for backwards compatibility, but are otherwise unused.
> @@ -1136,8 +1145,16 @@ always terminated with the dollar (
>  .B $
>  ) token.
>  .TP
> +.BI atime= value
> +If set to 1, when we're populating the root filesystem from a directory (
> +.B file=directory
> +option)
> +access times are going to be preserved and are copied from the source files.
> +Set to 0 to set access times to the current time instead.
> +By default, this is set to 0.
> +.TP
>  .BI slashes_are_spaces= value
> -If set to 1, slashes ("/") in the first token of each line of the protofile
> +If set to 1, slashes ("/") in the first token of each line of the prototype file
>  are converted to spaces.
>  This enables the creation of a filesystem containing filenames with spaces.
>  By default, this is set to 0.
> diff --git a/mkfs/proto.c b/mkfs/proto.c
> index 7f56a3d8..ffd580a2 100644
> --- a/mkfs/proto.c
> +++ b/mkfs/proto.c
> @@ -5,6 +5,9 @@
>   */
>  
>  #include "libxfs.h"
> +#include <dirent.h>
> +#include <fcntl.h>
> +#include <sys/resource.h>
>  #include <sys/stat.h>
>  #include <sys/xattr.h>
>  #include <linux/xattr.h>
> @@ -21,6 +24,11 @@ static void rsvfile(xfs_mount_t *mp, xfs_inode_t *ip, long long len);
>  static int newregfile(char **pp, char **fname);
>  static void rtinit(xfs_mount_t *mp);
>  static off_t filesize(int fd);
> +static void populate_from_dir(struct xfs_mount *mp,
> +				struct fsxattr *fsxp, char *source_dir);
> +static void walk_dir(struct xfs_mount *mp, struct xfs_inode *pip,
> +				struct fsxattr *fsxp, char *path_buf);
> +static int preserve_atime;
>  static int slashes_are_spaces;
>  
>  /*
> @@ -54,7 +62,7 @@ getnum(
>  	return i;
>  }
>  
> -char *
> +struct proto_source
>  setup_proto(
>  	char	*fname)
>  {
> @@ -63,8 +71,36 @@ setup_proto(
>  	int		fd;
>  	long		size;
>  
> -	if (!fname)
> -		return dflt;
> +	struct proto_source	result = {0};
> +	struct stat	statbuf;
> +
> +	/*
> +	 * for no input, use default root inode
> +	 * this is actually a protofile, which
> +	 * is valid.

I think this could be better worded as "If no prototype path is
supplied, use the default protofile which creates only a root
directory."

> +	 */
> +	if (!fname) {
> +		result.type = PROTO_SRC_PROTOFILE;
> +		result.data = dflt;
> +		return result;
> +	}
> +
> +	if (stat(fname, &statbuf) < 0) {
> +		fail(_("invalid or unreadable source path"), ENOENT);

Um, why not feed errno to fail()?  It doesn't make sense to squash any
number of errors to "File not found".

> +	}
> +
> +	/*
> +	 * handle directory inputs
> +	 */
> +	if (S_ISDIR(statbuf.st_mode)) {
> +		result.type = PROTO_SRC_DIR;
> +		result.data = fname;
> +		return result;
> +	}
> +
> +	/*
> +	 * else this is a protofile, let's handle traditionally
> +	 */
>  	if ((fd = open(fname, O_RDONLY)) < 0 || (size = filesize(fd)) < 0) {
>  		fprintf(stderr, _("%s: failed to open %s: %s\n"),
>  			progname, fname, strerror(errno));
> @@ -90,7 +126,10 @@ setup_proto(
>  	(void)getnum(getstr(&buf), 0, 0, false);	/* block count */
>  	(void)getnum(getstr(&buf), 0, 0, false);	/* inode count */
>  	close(fd);
> -	return buf;
> +
> +	result.type = PROTO_SRC_PROTOFILE;
> +	result.data = buf;
> +	return result;

/me sighs for

enum Prototype {
    File(String),
    Dir(std::path::PathBuf)
}

-EWRONGLANGUAGE :(

>  out_fail:
>  	if (fd >= 0)
> @@ -379,11 +418,19 @@ writeattr(
>  	int			error;
>  
>  	ret = fgetxattr(fd, attrname, valuebuf, valuelen);
> +	/*
> +	 * in case of filedescriptors with O_PATH, fgetxattr() will
> +	 * fail with EBADF. let's try to fallback to lgetxattr() using input
> +	 * path.
> +	 */
> +	if (ret < 0 && errno == EBADF)
> +		ret = lgetxattr(fname, attrname, valuebuf, valuelen);
>  	if (ret < 0) {
>  		if (errno == EOPNOTSUPP)
>  			return;
>  		fail(_("error collecting xattr value"), errno);
>  	}
> +
>  	if (ret == 0)
>  		return;
>  
> @@ -425,6 +472,13 @@ writeattrs(
>  		fail(_("error allocating xattr name buffer"), errno);
>  
>  	ret = flistxattr(fd, namebuf, XATTR_LIST_MAX);
> +	/*
> +	 * in case of filedescriptors with O_PATH, flistxattr() will
> +	 * fail with EBADF. let's try to fallback to llistxattr() using input
> +	 * path.
> +	 */
> +	if (ret < 0 && errno == EBADF)
> +		ret = llistxattr(fname, namebuf, XATTR_LIST_MAX);
>  	if (ret < 0) {
>  		if (errno == EOPNOTSUPP)
>  			goto out_namebuf;
> @@ -933,11 +987,27 @@ void
>  parse_proto(
>  	xfs_mount_t	*mp,
>  	struct fsxattr	*fsx,
> -	char		**pp,
> -	int		proto_slashes_are_spaces)
> +	struct proto_source	*protosource,
> +	int		proto_slashes_are_spaces,
> +	int		proto_preserve_atime)
>  {
>  	slashes_are_spaces = proto_slashes_are_spaces;
> -	parseproto(mp, NULL, fsx, pp, NULL);
> +	preserve_atime = proto_preserve_atime;
> +
> +	/*
> +	 * in case of a file input, we will use the prototype file logic
> +	 * else we will fallback to populate from dir.
> +	 */
> +	switch(protosource->type) {
> +	case PROTO_SRC_PROTOFILE:
> +		parseproto(mp, NULL, fsx, &protosource->data, NULL);
> +		break;
> +	case PROTO_SRC_DIR:
> +		populate_from_dir(mp, fsx, protosource->data);
> +		break;
> +	case PROTO_SRC_NONE:
> +		fail(_("invalid or unreadable source path"), ENOENT);

Where is PROTO_SRC_NONE set?

> +	}
>  }
>  
>  /* Create a sb-rooted metadata file. */
> @@ -1171,3 +1241,676 @@ filesize(
>  		return -1;
>  	return stb.st_size;
>  }
> +
> +/* Try to allow as many memfds as possible. */

memfds?  Do you mean open prototype directories?

> +static void
> +bump_max_fds(void)
> +{
> +	struct rlimit	rlim = {};
> +	int ret;
> +
> +	ret = getrlimit(RLIMIT_NOFILE, &rlim);
> +	if (ret)
> +		return;
> +
> +	rlim.rlim_cur = rlim.rlim_max;
> +	ret = setrlimit(RLIMIT_NOFILE, &rlim);
> +	if (ret < 0)
> +		fprintf(stderr, _("%s: could not bump fd limit: [ %d - %s]\n"),
> +				progname, errno, strerror(errno));
> +}
> +
> +static void
> +writefsxattrs(
> +	struct xfs_inode	*ip,
> +	struct fsxattr		*fsxp)
> +{
> +	ip->i_projid = fsxp->fsx_projid;
> +	ip->i_extsize = fsxp->fsx_extsize;
> +	ip->i_diflags = xfs_flags2diflags(ip, fsxp->fsx_xflags);
> +	if (xfs_has_v3inodes(ip->i_mount)) {
> +		ip->i_diflags2 = xfs_flags2diflags2(ip, fsxp->fsx_xflags);
> +		ip->i_cowextsize = fsxp->fsx_cowextsize;
> +	}
> +}
> +
> +static void
> +writetimestamps(
> +	struct xfs_inode	*ip,
> +	struct stat	statbuf)

These   ^ columns still need to lined up properly:

	struct xfs_inode	*ip,
	struct stat		statbuf)
{
	struct timespec64	ts;

I'm also not sure why you're passing the statbuf by value instead of
reference.

> +{
> +	struct timespec64	ts;
> +
> +	/*
> +	 * Copy timestamps from source file to destination inode.
> +	 * Usually reproducible archives will delete or not register
> +	 * atime and ctime, for example:
> +	 *    https://www.gnu.org/software/tar/manual/html_section/Reproducibility.html
> +	 * hence we will only copy mtime, and let ctime/crtime be set to
> +	 * current time.
> +	 * atime will be copied over if atime is true.
> +	 */
> +	ts.tv_sec = statbuf.st_mtim.tv_sec;
> +	ts.tv_nsec = statbuf.st_mtim.tv_nsec;
> +	inode_set_mtime_to_ts(VFS_I(ip), ts);
> +
> +	/*
> +	 * in case of atime option, we will copy the atime
> +	 * timestamp from source.
> +	 */
> +	if (preserve_atime) {
> +		ts.tv_sec = statbuf.st_atim.tv_sec;
> +		ts.tv_nsec = statbuf.st_atim.tv_nsec;
> +		inode_set_atime_to_ts(VFS_I(ip), ts);
> +	}
> +}
> +
> +struct hardlink {
> +	xfs_ino_t	src_ino;

ino_t for src_ino.  Don't cast when you don't have to.

> +	xfs_ino_t	dst_ino;
> +};
> +
> +struct hardlinks {
> +	size_t		count;
> +	size_t		size;
> +	struct hardlink	*entries;
> +};
> +
> +/* Growth strategy for hardlink tracking array */
> +#define HARDLINK_DEFAULT_GROWTH_FACTOR	2		/* Double size for small arrays */
> +#define HARDLINK_LARGE_GROWTH_FACTOR	0.25	/* Grow by 25% for large arrays */
> +#define HARDLINK_THRESHOLD				1024	/* Threshold to switch growth strategies */
> +#define HARDLINK_TRACKER_INITIAL_SIZE	4096	/* Initial allocation size */
> +
> +/*
> + * keep track of source inodes that are from hardlinks
> + * so we can retrieve them when needed to setup in
> + * destination.
> + */
> +static struct hardlinks *hardlink_tracker = { 0 };

Why is this global variable a pointer?  You could define the entire
struct and then 1) hardlink_tracker would be initialized to zeroes at
program start and 2) only hardlink_tracker.entries would have to be
allocated dynamically.

> +
> +static void
> +init_hardlink_tracker(void)
> +{
> +	hardlink_tracker = calloc(1, sizeof(struct hardlinks));
> +	if (!hardlink_tracker)
> +		fail(_("error allocating hardlinks tracking array"), errno);
> +
> +	hardlink_tracker->size = HARDLINK_TRACKER_INITIAL_SIZE;
> +	hardlink_tracker->entries = calloc(
> +			hardlink_tracker->size,
> +			sizeof(struct hardlink));
> +	if (!hardlink_tracker->entries)
> +		fail(_("error allocating hardlinks tracking array"), errno);
> +}
> +
> +static void
> +cleanup_hardlink_tracker(void)
> +{
> +	free(hardlink_tracker->entries);
> +	free(hardlink_tracker);
> +	hardlink_tracker = NULL;
> +}
> +
> +static xfs_ino_t
> +get_hardlink_dst_inode(
> +	xfs_ino_t i_ino)

same indenting problems here and below

static xfs_ino_t
get_hardlink_dst_inode(
	ino_t	src_ino)
{

> +{
> +	for (size_t i = 0; i < hardlink_tracker->count; i++) {
> +		if (hardlink_tracker->entries[i].src_ino == i_ino) {
> +			return hardlink_tracker->entries[i].dst_ino;
> +		}
> +	}
> +	return 0;
> +}
> +
> +static void
> +track_hardlink_inode(
> +	xfs_ino_t src_ino,
> +	xfs_ino_t dst_ino)
> +{
> +	if (hardlink_tracker->count >= hardlink_tracker->size) {
> +		/*
> +		 * double for smaller capacity.
> +		 * instead grow by 25% steps for larger capacities.
> +		 */
> +		const size_t old_size = hardlink_tracker->size;
> +		size_t new_size = old_size * HARDLINK_DEFAULT_GROWTH_FACTOR;
> +		if (old_size > HARDLINK_THRESHOLD)
> +			new_size = old_size + (old_size * HARDLINK_LARGE_GROWTH_FACTOR);
> +
> +		struct hardlink *resized_array = reallocarray(
> +			hardlink_tracker->entries,
> +			new_size,
> +			sizeof(struct hardlink));
> +		if (!resized_array)
> +			fail(_("error enlarging hardlinks tracking array"), errno);
> +
> +		memset(&resized_array[old_size], 0,
> +				(new_size - old_size) * sizeof(struct hardlink));
> +
> +		hardlink_tracker->entries = resized_array;
> +		hardlink_tracker->size = new_size;
> +	}
> +
> +	hardlink_tracker->entries[hardlink_tracker->count].src_ino = src_ino;
> +	hardlink_tracker->entries[hardlink_tracker->count].dst_ino = dst_ino;
> +	hardlink_tracker->count++;
> +}
> +
> +/*
> + * this function will first check in our tracker if
> + * the input hardlink has already been stored, if not
> + * report false so create_file() can continue handling
> + * the inode as a regular file type, and later save
> + * the source inode in our buffer for future consumption.
> + */
> +static bool
> +handle_hardlink(
> +	struct xfs_mount	*mp,
> +	struct xfs_inode	*pip,
> +	struct xfs_name	xname,
> +	struct stat	file_stat)
> +{
> +	int error;
> +	struct xfs_inode	*ip;
> +	struct xfs_trans	*tp;
> +	struct xfs_parent_args *ppargs = NULL;
> +	tp = getres(mp, 0);
> +	ppargs = newpptr(mp);
> +
> +	xfs_ino_t dst_ino = get_hardlink_dst_inode(file_stat.st_ino);

Style nit: blank space after the variable declarations; mixing code and
declarations (yes, they're allowed now, but we try not to do that in the
xfs codebase); and the same column indneting problems.

> +	/*
> +	 * we didn't find the hardlink inode, this means
> +	 * it's the first time we see it, report error
> +	 * so create_file() can continue handling the inode
> +	 * as a regular file type, and later save
> +	 * the source inode in our buffer for future consumption.
> +	 */
> +	if (dst_ino == 0)
> +		return false;
> +
> +	error = libxfs_iget(mp, NULL, dst_ino, 0, &ip);
> +	if (error) {
> +		fprintf(stderr, _("failed to iget inode %lu\n"), dst_ino);

Print the error, perhaps?

> +		exit(1);
> +	}
> +
> +	/*
> +	* In case the inode was already in our tracker
> +	* we need to setup the hardlink and skip file
> +	* copy.
> +	*/
> +	libxfs_trans_ijoin(tp, pip, 0);
> +	libxfs_trans_ijoin(tp, ip, 0);
> +	newdirent(mp, tp, pip, &xname, ip, ppargs);
> +
> +	/*
> +	 * Increment the link count
> +	 */
> +	libxfs_bumplink(tp, ip);
> +
> +	libxfs_trans_log_inode(tp, ip, XFS_ILOG_CORE);
> +
> +	error = -libxfs_trans_commit(tp);
> +	if (error)
> +		fail(_("Error encountered creating file from prototype file"), error);
> +
> +	libxfs_parent_finish(mp, ppargs);
> +	libxfs_irele(ip);
> +
> +	return true;
> +}
> +
> +static void
> +create_file(
> +	struct xfs_mount	*mp,
> +	struct xfs_inode	*pip,
> +	struct fsxattr	*fsxp,
> +	int mode,
> +	struct cred	creds,
> +	struct xfs_name	xname,
> +	int flags,
> +	struct stat	file_stat,
> +	xfs_dev_t rdev,
> +	int fd,
> +	char *fname)

Urrggh, more column alignment problems here..

> +{
> +
> +	int error;
> +	struct xfs_inode	*ip;
> +	struct xfs_trans	*tp;
> +	struct xfs_parent_args *ppargs = NULL;
> +
> +	/*
> +	* if handle_hardlink() returns true it means the hardlink has
> +	* been correctly found and set, so we don't need to
> +	* do anything else.
> +	*/
> +	if (file_stat.st_nlink > 1 && handle_hardlink(mp, pip, xname, file_stat)) {
> +		close(fd);
> +		return;
> +	}
> +	/*
> +	 * if instead we have an error it means the hardlink
> +	 * was not registered, so we proceed to treat it like
> +	 * a regular file, and save it to our tracker later.
> +	 */
> +	tp = getres(mp, 0);
> +	ppargs = newpptr(mp);
> +
> +	error = creatproto(&tp, pip, mode, rdev, &creds, fsxp, &ip);
> +	if (error)
> +		fail(_("Inode allocation failed"), error);
> +
> +	libxfs_trans_ijoin(tp, pip, 0);
> +	newdirent(mp, tp, pip, &xname, ip, ppargs);
> +
> +	/*
> +	 * copy over timestamps
> +	 */
> +	writetimestamps(ip, file_stat);
> +
> +	libxfs_trans_log_inode(tp, ip, flags);
> +
> +	error = -libxfs_trans_commit(tp);
> +	if (error)
> +		fail(_("Error encountered creating file from prototype file"), error);
> +
> +	libxfs_parent_finish(mp, ppargs);
> +
> +	/*
> +	 * copy over file content, attributes,
> +	 * extended attributes and timestamps
> +	 *
> +	 * hardlinks will be skipped as fd will
> +	 * be closed before this.

Is this comment still accurate?  I thought this function returned
early if a hardlink was succesfully made.

> +	 */
> +	if (fd >= 0) {
> +		writefile(ip, fname, fd);
> +		writeattrs(ip, fname, fd);
> +		close(fd);
> +	}
> +	/*
> +	 * we do fsxattr also for file types where we don't have
> +	 * an fd, for example FIFOs
> +	 */
> +	writefsxattrs(ip, fsxp);
> +
> +	/*
> +	 * if we're here it means this is the first time we're
> +	 * encountering an hardlink, so we need to store it
> +	 */
> +	if (file_stat.st_nlink > 1)
> +		track_hardlink_inode(file_stat.st_ino, ip->i_ino);
> +
> +	libxfs_irele(ip);
> +}
> +
> +static void
> +handle_direntry(
> +	struct xfs_mount	*mp,
> +	struct xfs_inode	*pip,
> +	struct fsxattr	*fsxp,
> +	char *path_buf,
> +	struct dirent	*entry)
> +{
> +	char link_target[PATH_MAX];

If this buffer holds the symlink target, then shouldn't its length be
the maximum symlink target length on an xfs filesystem?

> +	int error;
> +	int fd = -1;
> +	int flags;
> +	int majdev;
> +	int mindev;
> +	int mode;
> +	struct stat	file_stat;
> +	struct xfs_name	xname;

Same indentation problems I've been noting all over this patch.

> +	struct xfs_inode	*ip;
> +	struct xfs_trans	*tp;
> +	struct xfs_parent_args *ppargs = NULL;
> +
> +	/*
> +	 * save original path length so we can
> +	 * restore the original value at the end
> +	 * of the function
> +	 */
> +	size_t path_save_len = strlen(path_buf);
> +	size_t path_len = path_save_len;
> +	size_t entry_len = strlen(entry->d_name);
> +
> +	/*
> +	 * ensure the constructed path is within PATH_MAX limits
> +	 */
> +	size_t remaining = PATH_MAX - path_len;
> +	size_t written = snprintf(path_buf + path_len, remaining, "/%s",
> +			entry->d_name);
> +	if (written >= remaining) {
> +		fail(_("path name too long"), ENAMETOOLONG);
> +	}
> +
> +	if (lstat(path_buf, &file_stat) < 0) {
> +		fprintf(stderr, _("%s: cannot stat '%s': %s (errno=%d)\n"),
> +				progname, path_buf, strerror(errno), errno);
> +		exit(1);
> +	}
> +
> +	/*
> +	 * avoid opening FIFOs as they're blocking
> +	 */
> +	int open_flags = O_NOFOLLOW | O_RDONLY | O_NOATIME;
> +	/*
> +	* symlinks and sockets will need to be opened with O_PATH to work,
> +	* so we handle this special case.
> +	*/
> +	if (S_ISSOCK(file_stat.st_mode)
> +			|| S_ISLNK(file_stat.st_mode)
> +			|| S_ISFIFO(file_stat.st_mode))

Not sure why you sometimes put the boolean logic operator on the
preceeding line (e.g. the handle_hardlink conditional below) in some
places but on the continuation line as is done here.

> +		open_flags = O_NOFOLLOW | O_PATH;
> +	if ((fd = open(path_buf, open_flags)) < 0) {
> +		fprintf(stderr, _("%s: cannot open %s: %s\n"), progname, path_buf,
> +			strerror(errno));
> +		exit(1);
> +	}
> +
> +	struct cred creds = {
> +		.cr_uid = file_stat.st_uid,
> +		.cr_gid = file_stat.st_gid,
> +	};
> +
> +	xname.name = (unsigned char *)entry->d_name;
> +	xname.len = entry_len;
> +	xname.type = 0;
> +	mode = file_stat.st_mode;
> +	flags = XFS_ILOG_CORE;
> +
> +	switch (file_stat.st_mode & S_IFMT) {
> +	case S_IFDIR:
> +		tp = getres(mp, 0);
> +		ppargs = newpptr(mp);
> +
> +		error = creatproto(&tp, pip, mode, 0, &creds, fsxp, &ip);
> +		if (error)
> +			fail(_("Inode allocation failed"), error);
> +
> +		libxfs_trans_ijoin(tp, pip, 0);
> +
> +		xname.type = XFS_DIR3_FT_DIR;
> +		newdirent(mp, tp, pip, &xname, ip, ppargs);
> +
> +		libxfs_bumplink(tp, pip);
> +		libxfs_trans_log_inode(tp, pip, XFS_ILOG_CORE);
> +		newdirectory(mp, tp, ip, pip);
> +
> +		/*
> +		 * copy over timestamps
> +		 */
> +		writetimestamps(ip, file_stat);
> +
> +		libxfs_trans_log_inode(tp, ip, flags);
> +
> +		error = -libxfs_trans_commit(tp);
> +		if (error)
> +			fail(_("Directory inode allocation failed."), error);
> +
> +		libxfs_parent_finish(mp, ppargs);
> +		tp = NULL;
> +
> +		/*
> +		 * copy over attributes
> +		 */
> +		writeattrs(ip, entry->d_name, fd);
> +		writefsxattrs(ip, fsxp);
> +		close(fd);
> +
> +		walk_dir(mp, ip, fsxp, path_buf);
> +
> +		libxfs_irele(ip);
> +		break;
> +	case S_IFLNK:
> +		/*
> +		* if handle_hardlink() returns true it means the hardlink has
> +		* been correctly found and set, so we don't need to
> +		* do anything else.
> +		*/
> +		if (file_stat.st_nlink > 1 &&
> +				handle_hardlink(mp, pip, xname, file_stat)) {
> +			close(fd);
> +			break;
> +		}
> +		/*
> +		* if instead we have false it means the hardlink
> +		* was not registered, so we proceed to treat it like
> +		* a regular symlink, and save it to our tracker later.
> +		*/
> +		ssize_t len = readlink(path_buf, link_target, PATH_MAX - 1);
> +		if (len < 0)
> +			fail(_("could not resolve symlink"), errno);
> +		if (len >= PATH_MAX -1)
> +			fail(_("symlink target too long"), ENAMETOOLONG);
> +		link_target[len] = '\0';
> +
> +		tp = getres(mp, XFS_B_TO_FSB(mp, len));
> +		ppargs = newpptr(mp);
> +
> +		error = creatproto(&tp, pip, mode, 0, &creds, fsxp, &ip);
> +		if (error)
> +			fail(_("Inode allocation failed"), error);
> +
> +		writesymlink(tp, ip, link_target, len);
> +		libxfs_trans_ijoin(tp, pip, 0);
> +
> +		xname.type = XFS_DIR3_FT_SYMLINK;
> +		newdirent(mp, tp, pip, &xname, ip, ppargs);
> +
> +		/*
> +		 * copy over timestamps
> +		 */
> +		writetimestamps(ip, file_stat);
> +
> +		libxfs_trans_log_inode(tp, ip, flags);
> +
> +		error = -libxfs_trans_commit(tp);
> +		if (error)
> +			fail(_("Error encountered creating file from prototype file"),
> +			     error);
> +
> +		libxfs_parent_finish(mp, ppargs);
> +
> +		/*
> +		 * copy over attributes
> +		 *
> +		 * being a symlink we opened the filedescriptor with O_PATH
> +		 * this will make flistxattr() and fgetxattr() fail wil EBADF,
> +		 * so we  will need to fallback to llistxattr() and lgetxattr(),
> +		 * this will need the full path to the original file, not just the
> +		 * entry name.
> +		 */
> +		writeattrs(ip, path_buf, fd);
> +		writefsxattrs(ip, fsxp);
> +		close(fd);
> +
> +		/*
> +		 * if we're here it means this is the first time we're
> +		 * encountering an hardlink, so we need to store it
> +		 */
> +		if (file_stat.st_nlink > 1)
> +			track_hardlink_inode(file_stat.st_ino, ip->i_ino);
> +
> +		libxfs_irele(ip);
> +		break;
> +	case S_IFREG:
> +		xname.type = XFS_DIR3_FT_REG_FILE;
> +		create_file(mp, pip, fsxp, mode, creds, xname, flags, file_stat,
> +			    0, fd, entry->d_name);
> +		break;
> +	case S_IFCHR:
> +		xname.type = XFS_DIR3_FT_CHRDEV;
> +		majdev = major(file_stat.st_rdev);
> +		mindev = minor(file_stat.st_rdev);
> +		create_file(mp, pip, fsxp, mode, creds, xname, flags, file_stat,
> +			    IRIX_MKDEV(majdev, mindev), fd, entry->d_name);
> +		break;
> +	case S_IFBLK:
> +		xname.type = XFS_DIR3_FT_BLKDEV;
> +		majdev = major(file_stat.st_rdev);
> +		mindev = minor(file_stat.st_rdev);
> +		create_file(mp, pip, fsxp, mode, creds, xname, flags, file_stat,
> +			    IRIX_MKDEV(majdev, mindev), fd, entry->d_name);
> +		break;
> +	case S_IFIFO:
> +		flags |= XFS_ILOG_DEV;
> +		/*
> +		 * being a fifo we opened the filedescriptor with O_PATH
> +		 * this will make flistxattr() and fgetxattr() fail wil EBADF,
> +		 * so we  will need to fallback to llistxattr() and lgetxattr(),
> +		 * this will need the full path to the original file, not just the
> +		 * entry name.
> +		 */
> +		create_file(mp, pip, fsxp, mode, creds, xname, flags, file_stat,
> +			    0, fd, path_buf);
> +		break;
> +	case S_IFSOCK:
> +		flags |= XFS_ILOG_DEV;

Why do you log the device number for sockets and fifos?  They don't have
device numbers, only block and char devices do.  Why is this missing for
those two cases?

> +		/*
> +		 * being a socket we opened the filedescriptor with O_PATH
> +		 * this will make flistxattr() and fgetxattr() fail wil EBADF,
> +		 * so we  will need to fallback to llistxattr() and lgetxattr(),
> +		 * this will need the full path to the original file, not just the
> +		 * entry name.
> +		 */
> +		create_file(mp, pip, fsxp, mode, creds, xname, flags, file_stat,
> +			    0, fd, path_buf);
> +		break;
> +	default:
> +		break;
> +	}
> +
> +	/*
> +	 * restore path buffer to original length before returning
> +	 * */
> +	path_buf[path_save_len] = '\0';
> +}
> +
> +/*
> + * walk_dir will recursively list files and directories
> + * and populate the mountpoint *mp with them using handle_direntry().
> + */
> +static void
> +walk_dir(
> +	struct xfs_mount	*mp,
> +	struct xfs_inode	*pip,
> +	struct fsxattr	*fsxp,
> +	char *path_buf)
> +{
> +	DIR *dir;
> +	struct dirent	*entry;

More column alignment problems...

> +
> +	/*
> +	 * open input directory and iterate over all entries in it.
> +	 * when another directory is found, we will recursively call
> +	 * walk_dir.
> +	 */
> +	if ((dir = opendir(path_buf)) == NULL) {
> +		fprintf(stderr, _("%s: cannot open input dir: %s [%d - %s]\n"),
> +				progname, path_buf, errno, strerror(errno));
> +		exit(1);
> +	}
> +	while ((entry = readdir(dir)) != NULL) {
> +		if (strcmp(entry->d_name, ".") == 0 ||
> +				strcmp(entry->d_name, "..") == 0) {

Continuations of conditionals should be aligned so that the strings
line up:

		if (strcmp(entry->d_name, ".") == 0 ||
		    strcmp(entry->d_name, "..") == 0)
			continue;

> +			continue;
> +		}
> +
> +		handle_direntry(mp, pip, fsxp, path_buf, entry);
> +	}
> +	closedir(dir);
> +}
> +
> +static void
> +populate_from_dir(
> +	struct xfs_mount	*mp,
> +	struct fsxattr	*fsxp,
> +	char	*cur_path)
> +{
> +	int error;
> +	int mode;
> +	struct xfs_inode	*ip;
> +	struct xfs_trans	*tp;

More column alignment problems...

> +
> +	char			path_buf[PATH_MAX];
> +
> +	/*
> +	 * initialize path_buf cur_path, strip trailing slashes
> +	 * they're automatically added when walking the dir
> +	 */
> +	if (strlen(cur_path) > 1 && cur_path[strlen(cur_path)-1] == '/')
> +		cur_path[strlen(cur_path)-1] = '\0';

When is cur_path not null terminated?

> +	if (snprintf(path_buf, PATH_MAX, "%s", cur_path) >= PATH_MAX)
> +		fail(_("path name too long"), ENAMETOOLONG);
> +
> +	/*
> +	 * we first ensure we have the root inode
> +	 */
> +	struct cred creds = {
> +		.cr_uid = 0,
> +		.cr_gid = 0,
> +
> +	};
> +	mode = S_IRWXU | S_IRGRP | S_IXGRP | S_IROTH | S_IXOTH;

Why doesn't the root directory get its owner/mode/fsxattrs from the
protodir like everything else?

--D

> +
> +	tp = getres(mp, 0);
> +
> +	error = creatproto(&tp, NULL, mode | S_IFDIR, 0, &creds, fsxp, &ip);
> +	if (error)
> +		fail(_("Inode allocation failed"), error);
> +
> +	mp->m_sb.sb_rootino = ip->i_ino;
> +	libxfs_log_sb(tp);
> +	newdirectory(mp, tp, ip, ip);
> +	libxfs_trans_log_inode(tp, ip, XFS_ILOG_CORE);
> +
> +	error = -libxfs_trans_commit(tp);
> +	if (error)
> +		fail(_("Inode allocation failed"), error);
> +
> +	libxfs_parent_finish(mp, NULL);
> +
> +	/*
> +	 * RT initialization.  Do this here to ensure that
> +	 * the RT inodes get placed after the root inode.
> +	 */
> +	error = create_metadir(mp);
> +	if (error)
> +		fail(_("Creation of the metadata directory inode failed"), error);
> +
> +	rtinit(mp);
> +
> +	/*
> +	 * by nature of walk_dir() we could be opening
> +	 * a great number of fds for deeply nested directory
> +	 * trees.
> +	 * try to bump max fds limit.
> +	 */
> +	bump_max_fds();
> +
> +	/*
> +	 * initialize the hardlinks tracker
> +	 */
> +	init_hardlink_tracker();
> +	/*
> +	 * now that we have a root inode, let's
> +	 * walk the input dir and populate the partition
> +	 */
> +	walk_dir(mp, ip, fsxp, path_buf);
> +
> +	/*
> +	 * cleanup hardlinks tracker
> +	 */
> +	cleanup_hardlink_tracker();
> +
> +	/*
> +	 * we free up our root inode
> +	 * only when we finished populating the
> +	 * root filesystem
> +	 */
> +	libxfs_irele(ip);
> +}
> diff --git a/mkfs/proto.h b/mkfs/proto.h
> index be1ceb45..476f7851 100644
> --- a/mkfs/proto.h
> +++ b/mkfs/proto.h
> @@ -6,9 +6,21 @@
>  #ifndef MKFS_PROTO_H_
>  #define MKFS_PROTO_H_
>  
> -char *setup_proto(char *fname);
> -void parse_proto(struct xfs_mount *mp, struct fsxattr *fsx, char **pp,
> -		int proto_slashes_are_spaces);
> +enum proto_source_type {
> +	PROTO_SRC_NONE = 0,
> +	PROTO_SRC_PROTOFILE,
> +	PROTO_SRC_DIR
> +};
> +struct proto_source {
> +	enum	proto_source_type type;
> +	char	*data;
> +};
> +
> +struct proto_source setup_proto(char *fname);
> +void parse_proto(struct xfs_mount *mp, struct fsxattr *fsx,
> +		 struct proto_source *protosource,
> +		 int proto_slashes_are_spaces,
> +		 int proto_preserve_atime);
>  void res_failed(int err);
>  
>  #endif /* MKFS_PROTO_H_ */
> diff --git a/mkfs/xfs_mkfs.c b/mkfs/xfs_mkfs.c
> index 3f4455d4..a32c077e 100644
> --- a/mkfs/xfs_mkfs.c
> +++ b/mkfs/xfs_mkfs.c
> @@ -121,6 +121,7 @@ enum {
>  
>  enum {
>  	P_FILE = 0,
> +	P_ATIME,
>  	P_SLASHES,
>  	P_MAX_OPTS,
>  };
> @@ -709,6 +710,7 @@ static struct opt_params popts = {
>  	.ini_section = "proto",
>  	.subopts = {
>  		[P_FILE] = "file",
> +		[P_ATIME] = "atime",
>  		[P_SLASHES] = "slashes_are_spaces",
>  		[P_MAX_OPTS] = NULL,
>  	},
> @@ -717,6 +719,12 @@ static struct opt_params popts = {
>  		  .conflicts = { { NULL, LAST_CONFLICT } },
>  		  .defaultval = SUBOPT_NEEDS_VAL,
>  		},
> +		{ .index = P_ATIME,
> +		  .conflicts = { { NULL, LAST_CONFLICT } },
> +		  .minval = 0,
> +		  .maxval = 1,
> +		  .defaultval = 1,
> +		},
>  		{ .index = P_SLASHES,
>  		  .conflicts = { { NULL, LAST_CONFLICT } },
>  		  .minval = 0,
> @@ -1045,6 +1053,7 @@ struct cli_params {
>  	int	lsunit;
>  	int	is_supported;
>  	int	proto_slashes_are_spaces;
> +	int	proto_atime;
>  	int	data_concurrency;
>  	int	log_concurrency;
>  	int	rtvol_concurrency;
> @@ -1170,6 +1179,7 @@ usage( void )
>  /* naming */		[-n size=num,version=2|ci,ftype=0|1,parent=0|1]]\n\
>  /* no-op info only */	[-N]\n\
>  /* prototype file */	[-p fname]\n\
> +/* populate from directory */	[-p dirname,atime=0|1]\n\
>  /* quiet */		[-q]\n\
>  /* realtime subvol */	[-r extsize=num,size=num,rtdev=xxx,rgcount=n,rgsize=n,\n\
>  			    concurrency=num]\n\
> @@ -2067,6 +2077,9 @@ proto_opts_parser(
>  	case P_SLASHES:
>  		cli->proto_slashes_are_spaces = getnum(value, opts, subopt);
>  		break;
> +	case P_ATIME:
> +		cli->proto_atime = getnum(value, opts, subopt);
> +		break;
>  	case P_FILE:
>  		fallthrough;
>  	default:
> @@ -5162,7 +5175,7 @@ main(
>  	int			discard = 1;
>  	int			force_overwrite = 0;
>  	int			quiet = 0;
> -	char			*protostring = NULL;
> +	struct proto_source	protosource;
>  	int			worst_freelist = 0;
>  
>  	struct libxfs_init	xi = {
> @@ -5311,8 +5324,6 @@ main(
>  	 */
>  	cfgfile_parse(&cli);
>  
> -	protostring = setup_proto(cli.protofile);
> -
>  	/*
>  	 * Extract as much of the valid config as we can from the CLI input
>  	 * before opening the libxfs devices.
> @@ -5480,7 +5491,11 @@ main(
>  	/*
>  	 * Allocate the root inode and anything else in the proto file.
>  	 */
> -	parse_proto(mp, &cli.fsx, &protostring, cli.proto_slashes_are_spaces);
> +	protosource = setup_proto(cli.protofile);
> +	parse_proto(mp, &cli.fsx,
> +			&protosource,
> +			cli.proto_slashes_are_spaces,
> +			cli.proto_atime);
>  
>  	/*
>  	 * Protect ourselves against possible stupidity
> -- 
> 2.49.0
> 
> 

Re: [PATCH v9 1/1] proto: add ability to populate a filesystem from a directory

[Luca Di Maio]

Hi Darrick, thanks a lot for your review, will follow back shortly with
a new patch version.

I'm sorry for all the alignment/intendation problems, I'll try my best
to find them all and fix.

Thanks
L.

> > +     case PROTO_SRC_NONE:
> > +             fail(_("invalid or unreadable source path"), ENOENT);
>
> Where is PROTO_SRC_NONE set?

Being the value 0, it is the default value, if nothing is set
Shouldn't happen in the code flow (as we fail() if input is invalid)
but thought it would be fine to keep the case there.

L.