[PATCHSET v3 0/2] xfs_db: add minimal directory navigation

[PATCHSET v3 0/2] xfs_db: add minimal directory navigation

[Darrick J. Wong]

Hi all,

This patchset improves the usability of xfs_db by enabling users to
navigate to inodes by path and to list the contents of directories.

v2: Various cleanups and reorganizing suggested by dchinner
v3: Rebase to 5.10-rc0

If you're going to start using this mess, you probably ought to just
pull from my git trees, which are linked below.

This is an extraordinary way to destroy everything.  Enjoy!
Comments and questions are, as always, welcome.

--D

xfsprogs git tree:
https://git.kernel.org/cgit/linux/kernel/git/djwong/xfsprogs-dev.git/log/?h=xfs_db-directory-navigation

fstests git tree:
https://git.kernel.org/cgit/linux/kernel/git/djwong/xfstests-dev.git/log/?h=xfs_db-directory-navigation
---
 db/Makefile              |    3 
 db/command.c             |    1 
 db/command.h             |    1 
 db/namei.c               |  612 ++++++++++++++++++++++++++++++++++++++++++++++
 libxfs/libxfs_api_defs.h |    1 
 man/man8/xfs_db.8        |   20 ++
 6 files changed, 637 insertions(+), 1 deletion(-)
 create mode 100644 db/namei.c

[PATCH 1/2] xfs_db: add a directory path lookup command

[Darrick J. Wong]

From: Darrick J. Wong <djwong@kernel.org>

Add a command to xfs_db so that we can navigate to inodes by path.

Signed-off-by: Darrick J. Wong <djwong@kernel.org>
---
 db/Makefile       |    3 -
 db/command.c      |    1 
 db/command.h      |    1 
 db/namei.c        |  223 +++++++++++++++++++++++++++++++++++++++++++++++++++++
 man/man8/xfs_db.8 |    4 +
 5 files changed, 231 insertions(+), 1 deletion(-)
 create mode 100644 db/namei.c


diff --git a/db/Makefile b/db/Makefile
index 9d502bf0..beafb105 100644
--- a/db/Makefile
+++ b/db/Makefile
@@ -14,7 +14,8 @@ HFILES = addr.h agf.h agfl.h agi.h attr.h attrshort.h bit.h block.h bmap.h \
 	io.h logformat.h malloc.h metadump.h output.h print.h quit.h sb.h \
 	sig.h strvec.h text.h type.h write.h attrset.h symlink.h fsmap.h \
 	fuzz.h
-CFILES = $(HFILES:.h=.c) btdump.c btheight.c convert.c info.c timelimit.c
+CFILES = $(HFILES:.h=.c) btdump.c btheight.c convert.c info.c namei.c \
+	timelimit.c
 LSRCFILES = xfs_admin.sh xfs_ncheck.sh xfs_metadump.sh
 
 LLDLIBS	= $(LIBXFS) $(LIBXLOG) $(LIBFROG) $(LIBUUID) $(LIBRT) $(LIBPTHREAD)
diff --git a/db/command.c b/db/command.c
index 43828369..02f778b9 100644
--- a/db/command.c
+++ b/db/command.c
@@ -131,6 +131,7 @@ init_commands(void)
 	logformat_init();
 	io_init();
 	metadump_init();
+	namei_init();
 	output_init();
 	print_init();
 	quit_init();
diff --git a/db/command.h b/db/command.h
index 6913c817..498983ff 100644
--- a/db/command.h
+++ b/db/command.h
@@ -33,3 +33,4 @@ extern void		btdump_init(void);
 extern void		info_init(void);
 extern void		btheight_init(void);
 extern void		timelimit_init(void);
+extern void		namei_init(void);
diff --git a/db/namei.c b/db/namei.c
new file mode 100644
index 00000000..eebebe15
--- /dev/null
+++ b/db/namei.c
@@ -0,0 +1,223 @@
+// SPDX-License-Identifier: GPL-2.0-or-later
+/*
+ * Copyright (C) 2021 Oracle.  All Rights Reserved.
+ * Author: Darrick J. Wong <djwong@kernel.org>
+ */
+#include "libxfs.h"
+#include "command.h"
+#include "output.h"
+#include "init.h"
+#include "io.h"
+#include "type.h"
+#include "input.h"
+#include "faddr.h"
+#include "fprint.h"
+#include "field.h"
+#include "inode.h"
+
+/* Path lookup */
+
+/* Key for looking up metadata inodes. */
+struct dirpath {
+	/* Array of string pointers. */
+	char		**path;
+
+	/* Number of strings in path. */
+	unsigned int	depth;
+};
+
+static void
+path_free(
+	struct dirpath	*dirpath)
+{
+	unsigned int	i;
+
+	for (i = 0; i < dirpath->depth; i++)
+		free(dirpath->path[i]);
+	free(dirpath->path);
+	free(dirpath);
+}
+
+/* Chop a freeform string path into a structured path. */
+static struct dirpath *
+path_parse(
+	const char	*path)
+{
+	struct dirpath	*dirpath;
+	const char	*p = path;
+	const char	*endp = path + strlen(path);
+
+	dirpath = calloc(sizeof(*dirpath), 1);
+	if (!dirpath)
+		return NULL;
+
+	while (p < endp) {
+		char		**new_path;
+		const char	*next_slash;
+
+		next_slash = strchr(p, '/');
+		if (next_slash == p) {
+			p++;
+			continue;
+		}
+		if (!next_slash)
+			next_slash = endp;
+
+		new_path = realloc(dirpath->path,
+				(dirpath->depth + 1) * sizeof(char *));
+		if (!new_path) {
+			path_free(dirpath);
+			return NULL;
+		}
+
+		dirpath->path = new_path;
+		dirpath->path[dirpath->depth] = strndup(p, next_slash - p);
+		dirpath->depth++;
+
+		p = next_slash + 1;
+	}
+
+	return dirpath;
+}
+
+/* Given a directory and a structured path, walk the path and set the cursor. */
+static int
+path_navigate(
+	struct xfs_mount	*mp,
+	xfs_ino_t		rootino,
+	struct dirpath		*dirpath)
+{
+	struct xfs_inode	*dp;
+	xfs_ino_t		ino = rootino;
+	unsigned int		i;
+	int			error;
+
+	error = -libxfs_iget(mp, NULL, ino, 0, &dp);
+	if (error)
+		return error;
+
+	for (i = 0; i < dirpath->depth; i++) {
+		struct xfs_name	xname = {
+			.name	= dirpath->path[i],
+			.len	= strlen(dirpath->path[i]),
+		};
+
+		if (!S_ISDIR(VFS_I(dp)->i_mode)) {
+			error = ENOTDIR;
+			goto rele;
+		}
+
+		error = -libxfs_dir_lookup(NULL, dp, &xname, &ino, NULL);
+		if (error)
+			goto rele;
+		if (!xfs_verify_ino(mp, ino)) {
+			error = EFSCORRUPTED;
+			goto rele;
+		}
+
+		libxfs_irele(dp);
+		dp = NULL;
+
+		error = -libxfs_iget(mp, NULL, ino, 0, &dp);
+		switch (error) {
+		case EFSCORRUPTED:
+		case EFSBADCRC:
+		case 0:
+			break;
+		default:
+			return error;
+		}
+	}
+
+	set_cur_inode(ino);
+rele:
+	if (dp)
+		libxfs_irele(dp);
+	return error;
+}
+
+/* Walk a directory path to an inode and set the io cursor to that inode. */
+static int
+path_walk(
+	char		*path)
+{
+	struct dirpath	*dirpath;
+	char		*p = path;
+	xfs_ino_t	rootino = mp->m_sb.sb_rootino;
+	int		error = 0;
+
+	if (*p == '/') {
+		/* Absolute path, start from the root inode. */
+		p++;
+	} else {
+		/* Relative path, start from current dir. */
+		if (iocur_top->typ != &typtab[TYP_INODE] ||
+		    !S_ISDIR(iocur_top->mode))
+			return ENOTDIR;
+
+		rootino = iocur_top->ino;
+	}
+
+	dirpath = path_parse(p);
+	if (!dirpath)
+		return ENOMEM;
+
+	error = path_navigate(mp, rootino, dirpath);
+	if (error)
+		return error;
+
+	path_free(dirpath);
+	return 0;
+}
+
+static void
+path_help(void)
+{
+	dbprintf(_(
+"\n"
+" Navigate to an inode via directory path.\n"
+	));
+}
+
+static int
+path_f(
+	int		argc,
+	char		**argv)
+{
+	int		c;
+	int		error;
+
+	while ((c = getopt(argc, argv, "")) != -1) {
+		switch (c) {
+		default:
+			path_help();
+			return 0;
+		}
+	}
+
+	error = path_walk(argv[optind]);
+	if (error) {
+		dbprintf("%s: %s\n", argv[optind], strerror(error));
+		exitcode = 1;
+	}
+
+	return 0;
+}
+
+static struct cmdinfo path_cmd = {
+	.name		= "path",
+	.altname	= NULL,
+	.cfunc		= path_f,
+	.argmin		= 1,
+	.argmax		= 1,
+	.canpush	= 0,
+	.args		= "",
+	.help		= path_help,
+};
+
+void
+namei_init(void)
+{
+	path_cmd.oneline = _("navigate to an inode by path");
+	add_command(&path_cmd);
+}
diff --git a/man/man8/xfs_db.8 b/man/man8/xfs_db.8
index 55388be6..4df265ec 100644
--- a/man/man8/xfs_db.8
+++ b/man/man8/xfs_db.8
@@ -831,6 +831,10 @@ See the
 .B print
 command.
 .TP
+.BI "path " dir_path
+Walk the directory tree to an inode using the supplied path.
+Absolute and relative paths are supported.
+.TP
 .B pop
 Pop location from the stack.
 .TP

[PATCH 2/2] xfs_db: add an ls command

[Darrick J. Wong]

From: Darrick J. Wong <djwong@kernel.org>

Add to xfs_db the ability to list a directory.

Signed-off-by: Darrick J. Wong <djwong@kernel.org>
---
 db/namei.c               |  389 ++++++++++++++++++++++++++++++++++++++++++++++
 libxfs/libxfs_api_defs.h |    1 
 man/man8/xfs_db.8        |   16 ++
 3 files changed, 406 insertions(+)


diff --git a/db/namei.c b/db/namei.c
index eebebe15..e75b5ebd 100644
--- a/db/namei.c
+++ b/db/namei.c
@@ -215,9 +215,398 @@ static struct cmdinfo path_cmd = {
 	.help		= path_help,
 };
 
+/* List a directory's entries. */
+
+static const char *filetype_strings[XFS_DIR3_FT_MAX] = {
+	[XFS_DIR3_FT_UNKNOWN]	= "unknown",
+	[XFS_DIR3_FT_REG_FILE]	= "regular",
+	[XFS_DIR3_FT_DIR]	= "directory",
+	[XFS_DIR3_FT_CHRDEV]	= "chardev",
+	[XFS_DIR3_FT_BLKDEV]	= "blkdev",
+	[XFS_DIR3_FT_FIFO]	= "fifo",
+	[XFS_DIR3_FT_SOCK]	= "socket",
+	[XFS_DIR3_FT_SYMLINK]	= "symlink",
+	[XFS_DIR3_FT_WHT]	= "whiteout",
+};
+
+static const char *
+get_dstr(
+	struct xfs_mount	*mp,
+	uint8_t			filetype)
+{
+	if (!xfs_sb_version_hasftype(&mp->m_sb))
+		return filetype_strings[XFS_DIR3_FT_UNKNOWN];
+
+	if (filetype >= XFS_DIR3_FT_MAX)
+		return filetype_strings[XFS_DIR3_FT_UNKNOWN];
+
+	return filetype_strings[filetype];
+}
+
+static void
+dir_emit(
+	struct xfs_mount	*mp,
+	xfs_dir2_dataptr_t	off,
+	char			*name,
+	ssize_t			namelen,
+	xfs_ino_t		ino,
+	uint8_t			dtype)
+{
+	char			*display_name;
+	struct xfs_name		xname = { .name = name };
+	const char		*dstr = get_dstr(mp, dtype);
+	xfs_dahash_t		hash;
+	bool			good;
+
+	if (namelen < 0) {
+		/* Negative length means that name is null-terminated. */
+		display_name = name;
+		xname.len = strlen(name);
+		good = true;
+	} else {
+		/*
+		 * Otherwise, name came from a directory entry, so we have to
+		 * copy the string to a buffer so that we can add the null
+		 * terminator.
+		 */
+		display_name = malloc(namelen + 1);
+		memcpy(display_name, name, namelen);
+		display_name[namelen] = 0;
+		xname.len = namelen;
+		good = libxfs_dir2_namecheck(name, namelen);
+	}
+	hash = libxfs_dir2_hashname(mp, &xname);
+
+	dbprintf("%-10u %-18llu %-14s 0x%08llx %3d %s %s\n", off & 0xFFFFFFFF,
+			ino, dstr, hash, xname.len,
+			display_name, good ? _("(good)") : _("(corrupt)"));
+
+	if (display_name != name)
+		free(display_name);
+}
+
+static int
+list_sfdir(
+	struct xfs_da_args		*args)
+{
+	struct xfs_inode		*dp = args->dp;
+	struct xfs_mount		*mp = dp->i_mount;
+	struct xfs_da_geometry		*geo = args->geo;
+	struct xfs_dir2_sf_entry	*sfep;
+	struct xfs_dir2_sf_hdr		*sfp;
+	xfs_ino_t			ino;
+	xfs_dir2_dataptr_t		off;
+	unsigned int			i;
+	uint8_t				filetype;
+
+	sfp = (struct xfs_dir2_sf_hdr *)dp->i_df.if_u1.if_data;
+
+	/* . and .. entries */
+	off = xfs_dir2_db_off_to_dataptr(geo, geo->datablk,
+			geo->data_entry_offset);
+	dir_emit(args->dp->i_mount, off, ".", -1, dp->i_ino, XFS_DIR3_FT_DIR);
+
+	ino = libxfs_dir2_sf_get_parent_ino(sfp);
+	off = xfs_dir2_db_off_to_dataptr(geo, geo->datablk,
+			geo->data_entry_offset +
+			libxfs_dir2_data_entsize(mp, sizeof(".") - 1));
+	dir_emit(args->dp->i_mount, off, "..", -1, ino, XFS_DIR3_FT_DIR);
+
+	/* Walk everything else. */
+	sfep = xfs_dir2_sf_firstentry(sfp);
+	for (i = 0; i < sfp->count; i++) {
+		ino = libxfs_dir2_sf_get_ino(mp, sfp, sfep);
+		filetype = libxfs_dir2_sf_get_ftype(mp, sfep);
+		off = xfs_dir2_db_off_to_dataptr(geo, geo->datablk,
+				xfs_dir2_sf_get_offset(sfep));
+
+		dir_emit(args->dp->i_mount, off, (char *)sfep->name,
+				sfep->namelen, ino, filetype);
+		sfep = libxfs_dir2_sf_nextentry(mp, sfp, sfep);
+	}
+
+	return 0;
+}
+
+/* List entries in block format directory. */
+static int
+list_blockdir(
+	struct xfs_da_args	*args)
+{
+	struct xfs_inode	*dp = args->dp;
+	struct xfs_mount	*mp = dp->i_mount;
+	struct xfs_buf		*bp;
+	struct xfs_da_geometry	*geo = mp->m_dir_geo;
+	xfs_dir2_dataptr_t	diroff;
+	unsigned int		offset;
+	unsigned int		end;
+	int			error;
+
+	error = xfs_dir3_block_read(NULL, dp, &bp);
+	if (error)
+		return error;
+
+	end = xfs_dir3_data_end_offset(geo, bp->b_addr);
+	for (offset = geo->data_entry_offset; offset < end;) {
+		struct xfs_dir2_data_unused	*dup = bp->b_addr + offset;
+		struct xfs_dir2_data_entry	*dep = bp->b_addr + offset;
+		uint8_t				filetype;
+
+		if (be16_to_cpu(dup->freetag) == XFS_DIR2_DATA_FREE_TAG) {
+			/* Unused entry */
+			offset += be16_to_cpu(dup->length);
+			continue;
+		}
+
+		/* Real entry */
+		diroff = xfs_dir2_db_off_to_dataptr(geo, geo->datablk, offset);
+		offset += libxfs_dir2_data_entsize(mp, dep->namelen);
+		filetype = libxfs_dir2_data_get_ftype(dp->i_mount, dep);
+		dir_emit(mp, diroff, (char *)dep->name, dep->namelen,
+				be64_to_cpu(dep->inumber), filetype);
+	}
+
+	libxfs_trans_brelse(args->trans, bp);
+	return error;
+}
+
+/* List entries in leaf format directory. */
+static int
+list_leafdir(
+	struct xfs_da_args	*args)
+{
+	struct xfs_bmbt_irec	map;
+	struct xfs_iext_cursor	icur;
+	struct xfs_inode	*dp = args->dp;
+	struct xfs_mount	*mp = dp->i_mount;
+	struct xfs_buf		*bp = NULL;
+	struct xfs_ifork	*ifp = XFS_IFORK_PTR(dp, XFS_DATA_FORK);
+	struct xfs_da_geometry	*geo = mp->m_dir_geo;
+	xfs_dir2_off_t		dirboff;
+	xfs_dablk_t		dabno = 0;
+	int			error = 0;
+
+	/* Read extent map. */
+	if (!(ifp->if_flags & XFS_IFEXTENTS)) {
+		error = -libxfs_iread_extents(NULL, dp, XFS_DATA_FORK);
+		if (error)
+			return error;
+	}
+
+	while (dabno < geo->leafblk) {
+		unsigned int	offset;
+		unsigned int	length;
+
+		/* Find mapping for leaf block. */
+		if (!xfs_iext_lookup_extent(dp, ifp, dabno, &icur, &map))
+			break;
+		if (map.br_startoff >= geo->leafblk)
+			break;
+		libxfs_trim_extent(&map, dabno, geo->leafblk - dabno);
+
+		/* Read the directory block of that first mapping. */
+		error = xfs_dir3_data_read(NULL, dp, map.br_startoff, 0, &bp);
+		if (error)
+			break;
+
+		dirboff = xfs_dir2_da_to_byte(geo, map.br_startoff);
+		for (offset = geo->data_entry_offset; offset < geo->blksize;) {
+			struct xfs_dir2_data_entry	*dep;
+			struct xfs_dir2_data_unused	*dup;
+			uint8_t				filetype;
+
+			dup = bp->b_addr + offset;
+			dep = bp->b_addr + offset;
+
+			if (be16_to_cpu(dup->freetag) ==
+			    XFS_DIR2_DATA_FREE_TAG) {
+				/* Skip unused entry */
+				length = be16_to_cpu(dup->length);
+				offset += length;
+				continue;
+			}
+
+			offset += libxfs_dir2_data_entsize(mp, dep->namelen);
+			filetype = libxfs_dir2_data_get_ftype(mp, dep);
+
+			dir_emit(mp, xfs_dir2_byte_to_dataptr(dirboff + offset),
+					(char *)dep->name, dep->namelen,
+					be64_to_cpu(dep->inumber), filetype);
+		}
+
+		dabno += XFS_DADDR_TO_FSB(mp, bp->b_length);
+		libxfs_buf_relse(bp);
+		bp = NULL;
+	}
+
+	if (bp)
+		libxfs_buf_relse(bp);
+
+	return error;
+}
+
+/* Read the directory, display contents. */
+int
+listdir(
+	struct xfs_inode	*dp)
+{
+	struct xfs_da_args	args = {
+		.dp		= dp,
+		.geo		= dp->i_mount->m_dir_geo,
+	};
+	int			error;
+	int			isblock;
+
+	if (dp->i_df.if_format == XFS_DINODE_FMT_LOCAL)
+		return list_sfdir(&args);
+
+	error = -libxfs_dir2_isblock(&args, &isblock);
+	if (error)
+		return error;
+
+	if (isblock)
+		return list_blockdir(&args);
+	return list_leafdir(&args);
+}
+
+/* List the inode number of the currently selected inode. */
+static int
+inum_cur(void)
+{
+	if (iocur_top->typ != &typtab[TYP_INODE])
+		return ENOENT;
+
+	dbprintf("%llu\n", iocur_top->ino);
+	return 0;
+}
+
+/* If the io cursor points to a directory, list its contents. */
+static int
+ls_cur(
+	char			*tag)
+{
+	struct xfs_inode	*dp;
+	int			error = 0;
+
+	if (iocur_top->typ != &typtab[TYP_INODE] ||
+	    !S_ISDIR(iocur_top->mode))
+		return ENOTDIR;
+
+	error = -libxfs_iget(mp, NULL, iocur_top->ino, 0, &dp);
+	if (error)
+		return error;
+
+	if (!S_ISDIR(VFS_I(dp)->i_mode)) {
+		error = ENOTDIR;
+		goto rele;
+	}
+
+	/* List the contents of a directory. */
+	if (tag)
+		dbprintf(_("%s:\n"), tag);
+
+	error = listdir(dp);
+	if (error)
+		goto rele;
+
+rele:
+	libxfs_irele(dp);
+	return error;
+}
+
+static void
+ls_help(void)
+{
+	dbprintf(_(
+"\n"
+" List the contents of the currently selected directory inode.\n"
+"\n"
+" Options:\n"
+"   -i -- Resolve the given paths to their corresponding inode numbers.\n"
+"         If no paths are given, display the current inode number.\n"
+"\n"
+" Directory contents will be listed in the format:\n"
+" dir_cookie	inode_number	type	hash	name_length	name\n"
+	));
+}
+
+static int
+ls_f(
+	int			argc,
+	char			**argv)
+{
+	bool			inum_only = false;
+	int			c;
+	int			error = 0;
+
+	while ((c = getopt(argc, argv, "i")) != -1) {
+		switch (c) {
+		case 'i':
+			inum_only = true;
+			break;
+		default:
+			ls_help();
+			return 0;
+		}
+	}
+
+	if (optind == argc) {
+		if (inum_only)
+			error = inum_cur();
+		else
+			error = ls_cur(NULL);
+		if (error) {
+			dbprintf("%s\n", strerror(error));
+			exitcode = 1;
+		}
+
+		return 0;
+	}
+
+	for (c = optind; c < argc; c++) {
+		push_cur();
+
+		error = path_walk(argv[c]);
+		if (error)
+			goto err_cur;
+
+		if (inum_only)
+			error = inum_cur();
+		else
+			error = ls_cur(argv[c]);
+		if (error)
+			goto err_cur;
+
+		pop_cur();
+	}
+
+	return 0;
+err_cur:
+	pop_cur();
+	if (error) {
+		dbprintf("%s: %s\n", argv[c], strerror(error));
+		exitcode = 1;
+	}
+	return 0;
+}
+
+static struct cmdinfo ls_cmd = {
+	.name		= "ls",
+	.altname	= "l",
+	.cfunc		= ls_f,
+	.argmin		= 0,
+	.argmax		= -1,
+	.canpush	= 0,
+	.args		= "[-i] [paths...]",
+	.help		= ls_help,
+};
+
 void
 namei_init(void)
 {
 	path_cmd.oneline = _("navigate to an inode by path");
 	add_command(&path_cmd);
+
+	ls_cmd.oneline = _("list directory contents");
+	add_command(&ls_cmd);
 }
diff --git a/libxfs/libxfs_api_defs.h b/libxfs/libxfs_api_defs.h
index 9492955d..9a00ce66 100644
--- a/libxfs/libxfs_api_defs.h
+++ b/libxfs/libxfs_api_defs.h
@@ -190,6 +190,7 @@
 #define xfs_trans_resv_calc		libxfs_trans_resv_calc
 #define xfs_trans_roll_inode		libxfs_trans_roll_inode
 #define xfs_trans_roll			libxfs_trans_roll
+#define xfs_trim_extent			libxfs_trim_extent
 
 #define xfs_verify_agbno		libxfs_verify_agbno
 #define xfs_verify_agino		libxfs_verify_agino
diff --git a/man/man8/xfs_db.8 b/man/man8/xfs_db.8
index 4df265ec..58727495 100644
--- a/man/man8/xfs_db.8
+++ b/man/man8/xfs_db.8
@@ -806,6 +806,22 @@ This makes it easier to find discrepancies in the reservation calculations
 between xfsprogs and the kernel, which will help when diagnosing minimum
 log size calculation errors.
 .TP
+.BI "ls [\-i] [" paths "]..."
+List the contents of a directory.
+If a path resolves to a directory, the directory will be listed.
+If no paths are supplied and the IO cursor points at a directory inode,
+the contents of that directory will be listed.
+
+The output format is:
+directory cookie, inode number, file type, hash, name length, name.
+.RS 1.0i
+.TP 0.4i
+.B \-i
+Resolve each of the given paths to an inode number and print that number.
+If no paths are given and the IO cursor points to an inode, print the inode
+number.
+.RE
+.TP
 .BI "metadump [\-egow] " filename
 Dumps metadata to a file. See
 .BR xfs_metadump (8)

[PATCHSET v5 0/2] xfs_db: add minimal directory navigation

[Darrick J. Wong]

Hi all,

This patchset improves the usability of xfs_db by enabling users to
navigate to inodes by path and to list the contents of directories.

v2: Various cleanups and reorganizing suggested by dchinner
v3: Rebase to 5.10-rc0
v4: fix memory leak
v5: pick up a review from Chandan; no other changes

If you're going to start using this mess, you probably ought to just
pull from my git trees, which are linked below.

This is an extraordinary way to destroy everything.  Enjoy!
Comments and questions are, as always, welcome.

--D

xfsprogs git tree:
https://git.kernel.org/cgit/linux/kernel/git/djwong/xfsprogs-dev.git/log/?h=xfs_db-directory-navigation

fstests git tree:
https://git.kernel.org/cgit/linux/kernel/git/djwong/xfstests-dev.git/log/?h=xfs_db-directory-navigation
---
 db/Makefile              |    3 
 db/command.c             |    1 
 db/command.h             |    1 
 db/namei.c               |  609 ++++++++++++++++++++++++++++++++++++++++++++++
 libxfs/libxfs_api_defs.h |    1 
 man/man8/xfs_db.8        |   20 ++
 6 files changed, 634 insertions(+), 1 deletion(-)
 create mode 100644 db/namei.c

[PATCH 1/2] xfs_db: add a directory path lookup command

[Darrick J. Wong]

From: Darrick J. Wong <djwong@kernel.org>

Add a command to xfs_db so that we can navigate to inodes by path.

Signed-off-by: Darrick J. Wong <djwong@kernel.org>
Reviewed-by: Chandan Babu R <chandanrlinux@gmail.com>
---
 db/Makefile       |    3 -
 db/command.c      |    1 
 db/command.h      |    1 
 db/namei.c        |  220 +++++++++++++++++++++++++++++++++++++++++++++++++++++
 man/man8/xfs_db.8 |    4 +
 5 files changed, 228 insertions(+), 1 deletion(-)
 create mode 100644 db/namei.c


diff --git a/db/Makefile b/db/Makefile
index 9d502bf0..beafb105 100644
--- a/db/Makefile
+++ b/db/Makefile
@@ -14,7 +14,8 @@ HFILES = addr.h agf.h agfl.h agi.h attr.h attrshort.h bit.h block.h bmap.h \
 	io.h logformat.h malloc.h metadump.h output.h print.h quit.h sb.h \
 	sig.h strvec.h text.h type.h write.h attrset.h symlink.h fsmap.h \
 	fuzz.h
-CFILES = $(HFILES:.h=.c) btdump.c btheight.c convert.c info.c timelimit.c
+CFILES = $(HFILES:.h=.c) btdump.c btheight.c convert.c info.c namei.c \
+	timelimit.c
 LSRCFILES = xfs_admin.sh xfs_ncheck.sh xfs_metadump.sh
 
 LLDLIBS	= $(LIBXFS) $(LIBXLOG) $(LIBFROG) $(LIBUUID) $(LIBRT) $(LIBPTHREAD)
diff --git a/db/command.c b/db/command.c
index 43828369..02f778b9 100644
--- a/db/command.c
+++ b/db/command.c
@@ -131,6 +131,7 @@ init_commands(void)
 	logformat_init();
 	io_init();
 	metadump_init();
+	namei_init();
 	output_init();
 	print_init();
 	quit_init();
diff --git a/db/command.h b/db/command.h
index 6913c817..498983ff 100644
--- a/db/command.h
+++ b/db/command.h
@@ -33,3 +33,4 @@ extern void		btdump_init(void);
 extern void		info_init(void);
 extern void		btheight_init(void);
 extern void		timelimit_init(void);
+extern void		namei_init(void);
diff --git a/db/namei.c b/db/namei.c
new file mode 100644
index 00000000..6fddbc4a
--- /dev/null
+++ b/db/namei.c
@@ -0,0 +1,220 @@
+// SPDX-License-Identifier: GPL-2.0-or-later
+/*
+ * Copyright (C) 2021 Oracle.  All Rights Reserved.
+ * Author: Darrick J. Wong <djwong@kernel.org>
+ */
+#include "libxfs.h"
+#include "command.h"
+#include "output.h"
+#include "init.h"
+#include "io.h"
+#include "type.h"
+#include "input.h"
+#include "faddr.h"
+#include "fprint.h"
+#include "field.h"
+#include "inode.h"
+
+/* Path lookup */
+
+/* Key for looking up metadata inodes. */
+struct dirpath {
+	/* Array of string pointers. */
+	char		**path;
+
+	/* Number of strings in path. */
+	unsigned int	depth;
+};
+
+static void
+path_free(
+	struct dirpath	*dirpath)
+{
+	unsigned int	i;
+
+	for (i = 0; i < dirpath->depth; i++)
+		free(dirpath->path[i]);
+	free(dirpath->path);
+	free(dirpath);
+}
+
+/* Chop a freeform string path into a structured path. */
+static struct dirpath *
+path_parse(
+	const char	*path)
+{
+	struct dirpath	*dirpath;
+	const char	*p = path;
+	const char	*endp = path + strlen(path);
+
+	dirpath = calloc(sizeof(*dirpath), 1);
+	if (!dirpath)
+		return NULL;
+
+	while (p < endp) {
+		char		**new_path;
+		const char	*next_slash;
+
+		next_slash = strchr(p, '/');
+		if (next_slash == p) {
+			p++;
+			continue;
+		}
+		if (!next_slash)
+			next_slash = endp;
+
+		new_path = realloc(dirpath->path,
+				(dirpath->depth + 1) * sizeof(char *));
+		if (!new_path) {
+			path_free(dirpath);
+			return NULL;
+		}
+
+		dirpath->path = new_path;
+		dirpath->path[dirpath->depth] = strndup(p, next_slash - p);
+		dirpath->depth++;
+
+		p = next_slash + 1;
+	}
+
+	return dirpath;
+}
+
+/* Given a directory and a structured path, walk the path and set the cursor. */
+static int
+path_navigate(
+	struct xfs_mount	*mp,
+	xfs_ino_t		rootino,
+	struct dirpath		*dirpath)
+{
+	struct xfs_inode	*dp;
+	xfs_ino_t		ino = rootino;
+	unsigned int		i;
+	int			error;
+
+	error = -libxfs_iget(mp, NULL, ino, 0, &dp);
+	if (error)
+		return error;
+
+	for (i = 0; i < dirpath->depth; i++) {
+		struct xfs_name	xname = {
+			.name	= dirpath->path[i],
+			.len	= strlen(dirpath->path[i]),
+		};
+
+		if (!S_ISDIR(VFS_I(dp)->i_mode)) {
+			error = ENOTDIR;
+			goto rele;
+		}
+
+		error = -libxfs_dir_lookup(NULL, dp, &xname, &ino, NULL);
+		if (error)
+			goto rele;
+		if (!xfs_verify_ino(mp, ino)) {
+			error = EFSCORRUPTED;
+			goto rele;
+		}
+
+		libxfs_irele(dp);
+		dp = NULL;
+
+		error = -libxfs_iget(mp, NULL, ino, 0, &dp);
+		switch (error) {
+		case EFSCORRUPTED:
+		case EFSBADCRC:
+		case 0:
+			break;
+		default:
+			return error;
+		}
+	}
+
+	set_cur_inode(ino);
+rele:
+	if (dp)
+		libxfs_irele(dp);
+	return error;
+}
+
+/* Walk a directory path to an inode and set the io cursor to that inode. */
+static int
+path_walk(
+	char		*path)
+{
+	struct dirpath	*dirpath;
+	char		*p = path;
+	xfs_ino_t	rootino = mp->m_sb.sb_rootino;
+	int		error = 0;
+
+	if (*p == '/') {
+		/* Absolute path, start from the root inode. */
+		p++;
+	} else {
+		/* Relative path, start from current dir. */
+		if (iocur_top->typ != &typtab[TYP_INODE] ||
+		    !S_ISDIR(iocur_top->mode))
+			return ENOTDIR;
+
+		rootino = iocur_top->ino;
+	}
+
+	dirpath = path_parse(p);
+	if (!dirpath)
+		return ENOMEM;
+
+	error = path_navigate(mp, rootino, dirpath);
+	path_free(dirpath);
+	return error;
+}
+
+static void
+path_help(void)
+{
+	dbprintf(_(
+"\n"
+" Navigate to an inode via directory path.\n"
+	));
+}
+
+static int
+path_f(
+	int		argc,
+	char		**argv)
+{
+	int		c;
+	int		error;
+
+	while ((c = getopt(argc, argv, "")) != -1) {
+		switch (c) {
+		default:
+			path_help();
+			return 0;
+		}
+	}
+
+	error = path_walk(argv[optind]);
+	if (error) {
+		dbprintf("%s: %s\n", argv[optind], strerror(error));
+		exitcode = 1;
+	}
+
+	return 0;
+}
+
+static struct cmdinfo path_cmd = {
+	.name		= "path",
+	.altname	= NULL,
+	.cfunc		= path_f,
+	.argmin		= 1,
+	.argmax		= 1,
+	.canpush	= 0,
+	.args		= "",
+	.help		= path_help,
+};
+
+void
+namei_init(void)
+{
+	path_cmd.oneline = _("navigate to an inode by path");
+	add_command(&path_cmd);
+}
diff --git a/man/man8/xfs_db.8 b/man/man8/xfs_db.8
index 55388be6..4df265ec 100644
--- a/man/man8/xfs_db.8
+++ b/man/man8/xfs_db.8
@@ -831,6 +831,10 @@ See the
 .B print
 command.
 .TP
+.BI "path " dir_path
+Walk the directory tree to an inode using the supplied path.
+Absolute and relative paths are supported.
+.TP
 .B pop
 Pop location from the stack.
 .TP

[PATCHSET v4 0/2] xfs_db: add minimal directory navigation

[Darrick J. Wong]

Hi all,

This patchset improves the usability of xfs_db by enabling users to
navigate to inodes by path and to list the contents of directories.

v2: Various cleanups and reorganizing suggested by dchinner
v3: Rebase to 5.10-rc0
v4: fix memory leak

If you're going to start using this mess, you probably ought to just
pull from my git trees, which are linked below.

This is an extraordinary way to destroy everything.  Enjoy!
Comments and questions are, as always, welcome.

--D

xfsprogs git tree:
https://git.kernel.org/cgit/linux/kernel/git/djwong/xfsprogs-dev.git/log/?h=xfs_db-directory-navigation

fstests git tree:
https://git.kernel.org/cgit/linux/kernel/git/djwong/xfstests-dev.git/log/?h=xfs_db-directory-navigation
---
 db/Makefile              |    3 
 db/command.c             |    1 
 db/command.h             |    1 
 db/namei.c               |  609 ++++++++++++++++++++++++++++++++++++++++++++++
 libxfs/libxfs_api_defs.h |    1 
 man/man8/xfs_db.8        |   20 ++
 6 files changed, 634 insertions(+), 1 deletion(-)
 create mode 100644 db/namei.c

[PATCH 1/2] xfs_db: add a directory path lookup command

[Darrick J. Wong]

From: Darrick J. Wong <djwong@kernel.org>

Add a command to xfs_db so that we can navigate to inodes by path.

Signed-off-by: Darrick J. Wong <djwong@kernel.org>
---
 db/Makefile       |    3 -
 db/command.c      |    1 
 db/command.h      |    1 
 db/namei.c        |  220 +++++++++++++++++++++++++++++++++++++++++++++++++++++
 man/man8/xfs_db.8 |    4 +
 5 files changed, 228 insertions(+), 1 deletion(-)
 create mode 100644 db/namei.c


diff --git a/db/Makefile b/db/Makefile
index 9d502bf0..beafb105 100644
--- a/db/Makefile
+++ b/db/Makefile
@@ -14,7 +14,8 @@ HFILES = addr.h agf.h agfl.h agi.h attr.h attrshort.h bit.h block.h bmap.h \
 	io.h logformat.h malloc.h metadump.h output.h print.h quit.h sb.h \
 	sig.h strvec.h text.h type.h write.h attrset.h symlink.h fsmap.h \
 	fuzz.h
-CFILES = $(HFILES:.h=.c) btdump.c btheight.c convert.c info.c timelimit.c
+CFILES = $(HFILES:.h=.c) btdump.c btheight.c convert.c info.c namei.c \
+	timelimit.c
 LSRCFILES = xfs_admin.sh xfs_ncheck.sh xfs_metadump.sh
 
 LLDLIBS	= $(LIBXFS) $(LIBXLOG) $(LIBFROG) $(LIBUUID) $(LIBRT) $(LIBPTHREAD)
diff --git a/db/command.c b/db/command.c
index 43828369..02f778b9 100644
--- a/db/command.c
+++ b/db/command.c
@@ -131,6 +131,7 @@ init_commands(void)
 	logformat_init();
 	io_init();
 	metadump_init();
+	namei_init();
 	output_init();
 	print_init();
 	quit_init();
diff --git a/db/command.h b/db/command.h
index 6913c817..498983ff 100644
--- a/db/command.h
+++ b/db/command.h
@@ -33,3 +33,4 @@ extern void		btdump_init(void);
 extern void		info_init(void);
 extern void		btheight_init(void);
 extern void		timelimit_init(void);
+extern void		namei_init(void);
diff --git a/db/namei.c b/db/namei.c
new file mode 100644
index 00000000..6fddbc4a
--- /dev/null
+++ b/db/namei.c
@@ -0,0 +1,220 @@
+// SPDX-License-Identifier: GPL-2.0-or-later
+/*
+ * Copyright (C) 2021 Oracle.  All Rights Reserved.
+ * Author: Darrick J. Wong <djwong@kernel.org>
+ */
+#include "libxfs.h"
+#include "command.h"
+#include "output.h"
+#include "init.h"
+#include "io.h"
+#include "type.h"
+#include "input.h"
+#include "faddr.h"
+#include "fprint.h"
+#include "field.h"
+#include "inode.h"
+
+/* Path lookup */
+
+/* Key for looking up metadata inodes. */
+struct dirpath {
+	/* Array of string pointers. */
+	char		**path;
+
+	/* Number of strings in path. */
+	unsigned int	depth;
+};
+
+static void
+path_free(
+	struct dirpath	*dirpath)
+{
+	unsigned int	i;
+
+	for (i = 0; i < dirpath->depth; i++)
+		free(dirpath->path[i]);
+	free(dirpath->path);
+	free(dirpath);
+}
+
+/* Chop a freeform string path into a structured path. */
+static struct dirpath *
+path_parse(
+	const char	*path)
+{
+	struct dirpath	*dirpath;
+	const char	*p = path;
+	const char	*endp = path + strlen(path);
+
+	dirpath = calloc(sizeof(*dirpath), 1);
+	if (!dirpath)
+		return NULL;
+
+	while (p < endp) {
+		char		**new_path;
+		const char	*next_slash;
+
+		next_slash = strchr(p, '/');
+		if (next_slash == p) {
+			p++;
+			continue;
+		}
+		if (!next_slash)
+			next_slash = endp;
+
+		new_path = realloc(dirpath->path,
+				(dirpath->depth + 1) * sizeof(char *));
+		if (!new_path) {
+			path_free(dirpath);
+			return NULL;
+		}
+
+		dirpath->path = new_path;
+		dirpath->path[dirpath->depth] = strndup(p, next_slash - p);
+		dirpath->depth++;
+
+		p = next_slash + 1;
+	}
+
+	return dirpath;
+}
+
+/* Given a directory and a structured path, walk the path and set the cursor. */
+static int
+path_navigate(
+	struct xfs_mount	*mp,
+	xfs_ino_t		rootino,
+	struct dirpath		*dirpath)
+{
+	struct xfs_inode	*dp;
+	xfs_ino_t		ino = rootino;
+	unsigned int		i;
+	int			error;
+
+	error = -libxfs_iget(mp, NULL, ino, 0, &dp);
+	if (error)
+		return error;
+
+	for (i = 0; i < dirpath->depth; i++) {
+		struct xfs_name	xname = {
+			.name	= dirpath->path[i],
+			.len	= strlen(dirpath->path[i]),
+		};
+
+		if (!S_ISDIR(VFS_I(dp)->i_mode)) {
+			error = ENOTDIR;
+			goto rele;
+		}
+
+		error = -libxfs_dir_lookup(NULL, dp, &xname, &ino, NULL);
+		if (error)
+			goto rele;
+		if (!xfs_verify_ino(mp, ino)) {
+			error = EFSCORRUPTED;
+			goto rele;
+		}
+
+		libxfs_irele(dp);
+		dp = NULL;
+
+		error = -libxfs_iget(mp, NULL, ino, 0, &dp);
+		switch (error) {
+		case EFSCORRUPTED:
+		case EFSBADCRC:
+		case 0:
+			break;
+		default:
+			return error;
+		}
+	}
+
+	set_cur_inode(ino);
+rele:
+	if (dp)
+		libxfs_irele(dp);
+	return error;
+}
+
+/* Walk a directory path to an inode and set the io cursor to that inode. */
+static int
+path_walk(
+	char		*path)
+{
+	struct dirpath	*dirpath;
+	char		*p = path;
+	xfs_ino_t	rootino = mp->m_sb.sb_rootino;
+	int		error = 0;
+
+	if (*p == '/') {
+		/* Absolute path, start from the root inode. */
+		p++;
+	} else {
+		/* Relative path, start from current dir. */
+		if (iocur_top->typ != &typtab[TYP_INODE] ||
+		    !S_ISDIR(iocur_top->mode))
+			return ENOTDIR;
+
+		rootino = iocur_top->ino;
+	}
+
+	dirpath = path_parse(p);
+	if (!dirpath)
+		return ENOMEM;
+
+	error = path_navigate(mp, rootino, dirpath);
+	path_free(dirpath);
+	return error;
+}
+
+static void
+path_help(void)
+{
+	dbprintf(_(
+"\n"
+" Navigate to an inode via directory path.\n"
+	));
+}
+
+static int
+path_f(
+	int		argc,
+	char		**argv)
+{
+	int		c;
+	int		error;
+
+	while ((c = getopt(argc, argv, "")) != -1) {
+		switch (c) {
+		default:
+			path_help();
+			return 0;
+		}
+	}
+
+	error = path_walk(argv[optind]);
+	if (error) {
+		dbprintf("%s: %s\n", argv[optind], strerror(error));
+		exitcode = 1;
+	}
+
+	return 0;
+}
+
+static struct cmdinfo path_cmd = {
+	.name		= "path",
+	.altname	= NULL,
+	.cfunc		= path_f,
+	.argmin		= 1,
+	.argmax		= 1,
+	.canpush	= 0,
+	.args		= "",
+	.help		= path_help,
+};
+
+void
+namei_init(void)
+{
+	path_cmd.oneline = _("navigate to an inode by path");
+	add_command(&path_cmd);
+}
diff --git a/man/man8/xfs_db.8 b/man/man8/xfs_db.8
index 55388be6..4df265ec 100644
--- a/man/man8/xfs_db.8
+++ b/man/man8/xfs_db.8
@@ -831,6 +831,10 @@ See the
 .B print
 command.
 .TP
+.BI "path " dir_path
+Walk the directory tree to an inode using the supplied path.
+Absolute and relative paths are supported.
+.TP
 .B pop
 Pop location from the stack.
 .TP

Re: [PATCH 1/2] xfs_db: add a directory path lookup command

[Chandan Babu R]

On 04 Feb 2021 at 01:13, Darrick J. Wong wrote:
> From: Darrick J. Wong <djwong@kernel.org>
>
> Add a command to xfs_db so that we can navigate to inodes by path.

Looks good to me.

Reviewed-by: Chandan Babu R <chandanrlinux@gmail.com>

>
> Signed-off-by: Darrick J. Wong <djwong@kernel.org>
> ---
>  db/Makefile       |    3 -
>  db/command.c      |    1 
>  db/command.h      |    1 
>  db/namei.c        |  220 +++++++++++++++++++++++++++++++++++++++++++++++++++++
>  man/man8/xfs_db.8 |    4 +
>  5 files changed, 228 insertions(+), 1 deletion(-)
>  create mode 100644 db/namei.c
>
>
> diff --git a/db/Makefile b/db/Makefile
> index 9d502bf0..beafb105 100644
> --- a/db/Makefile
> +++ b/db/Makefile
> @@ -14,7 +14,8 @@ HFILES = addr.h agf.h agfl.h agi.h attr.h attrshort.h bit.h block.h bmap.h \
>  	io.h logformat.h malloc.h metadump.h output.h print.h quit.h sb.h \
>  	sig.h strvec.h text.h type.h write.h attrset.h symlink.h fsmap.h \
>  	fuzz.h
> -CFILES = $(HFILES:.h=.c) btdump.c btheight.c convert.c info.c timelimit.c
> +CFILES = $(HFILES:.h=.c) btdump.c btheight.c convert.c info.c namei.c \
> +	timelimit.c
>  LSRCFILES = xfs_admin.sh xfs_ncheck.sh xfs_metadump.sh
>  
>  LLDLIBS	= $(LIBXFS) $(LIBXLOG) $(LIBFROG) $(LIBUUID) $(LIBRT) $(LIBPTHREAD)
> diff --git a/db/command.c b/db/command.c
> index 43828369..02f778b9 100644
> --- a/db/command.c
> +++ b/db/command.c
> @@ -131,6 +131,7 @@ init_commands(void)
>  	logformat_init();
>  	io_init();
>  	metadump_init();
> +	namei_init();
>  	output_init();
>  	print_init();
>  	quit_init();
> diff --git a/db/command.h b/db/command.h
> index 6913c817..498983ff 100644
> --- a/db/command.h
> +++ b/db/command.h
> @@ -33,3 +33,4 @@ extern void		btdump_init(void);
>  extern void		info_init(void);
>  extern void		btheight_init(void);
>  extern void		timelimit_init(void);
> +extern void		namei_init(void);
> diff --git a/db/namei.c b/db/namei.c
> new file mode 100644
> index 00000000..6fddbc4a
> --- /dev/null
> +++ b/db/namei.c
> @@ -0,0 +1,220 @@
> +// SPDX-License-Identifier: GPL-2.0-or-later
> +/*
> + * Copyright (C) 2021 Oracle.  All Rights Reserved.
> + * Author: Darrick J. Wong <djwong@kernel.org>
> + */
> +#include "libxfs.h"
> +#include "command.h"
> +#include "output.h"
> +#include "init.h"
> +#include "io.h"
> +#include "type.h"
> +#include "input.h"
> +#include "faddr.h"
> +#include "fprint.h"
> +#include "field.h"
> +#include "inode.h"
> +
> +/* Path lookup */
> +
> +/* Key for looking up metadata inodes. */
> +struct dirpath {
> +	/* Array of string pointers. */
> +	char		**path;
> +
> +	/* Number of strings in path. */
> +	unsigned int	depth;
> +};
> +
> +static void
> +path_free(
> +	struct dirpath	*dirpath)
> +{
> +	unsigned int	i;
> +
> +	for (i = 0; i < dirpath->depth; i++)
> +		free(dirpath->path[i]);
> +	free(dirpath->path);
> +	free(dirpath);
> +}
> +
> +/* Chop a freeform string path into a structured path. */
> +static struct dirpath *
> +path_parse(
> +	const char	*path)
> +{
> +	struct dirpath	*dirpath;
> +	const char	*p = path;
> +	const char	*endp = path + strlen(path);
> +
> +	dirpath = calloc(sizeof(*dirpath), 1);
> +	if (!dirpath)
> +		return NULL;
> +
> +	while (p < endp) {
> +		char		**new_path;
> +		const char	*next_slash;
> +
> +		next_slash = strchr(p, '/');
> +		if (next_slash == p) {
> +			p++;
> +			continue;
> +		}
> +		if (!next_slash)
> +			next_slash = endp;
> +
> +		new_path = realloc(dirpath->path,
> +				(dirpath->depth + 1) * sizeof(char *));
> +		if (!new_path) {
> +			path_free(dirpath);
> +			return NULL;
> +		}
> +
> +		dirpath->path = new_path;
> +		dirpath->path[dirpath->depth] = strndup(p, next_slash - p);
> +		dirpath->depth++;
> +
> +		p = next_slash + 1;
> +	}
> +
> +	return dirpath;
> +}
> +
> +/* Given a directory and a structured path, walk the path and set the cursor. */
> +static int
> +path_navigate(
> +	struct xfs_mount	*mp,
> +	xfs_ino_t		rootino,
> +	struct dirpath		*dirpath)
> +{
> +	struct xfs_inode	*dp;
> +	xfs_ino_t		ino = rootino;
> +	unsigned int		i;
> +	int			error;
> +
> +	error = -libxfs_iget(mp, NULL, ino, 0, &dp);
> +	if (error)
> +		return error;
> +
> +	for (i = 0; i < dirpath->depth; i++) {
> +		struct xfs_name	xname = {
> +			.name	= dirpath->path[i],
> +			.len	= strlen(dirpath->path[i]),
> +		};
> +
> +		if (!S_ISDIR(VFS_I(dp)->i_mode)) {
> +			error = ENOTDIR;
> +			goto rele;
> +		}
> +
> +		error = -libxfs_dir_lookup(NULL, dp, &xname, &ino, NULL);
> +		if (error)
> +			goto rele;
> +		if (!xfs_verify_ino(mp, ino)) {
> +			error = EFSCORRUPTED;
> +			goto rele;
> +		}
> +
> +		libxfs_irele(dp);
> +		dp = NULL;
> +
> +		error = -libxfs_iget(mp, NULL, ino, 0, &dp);
> +		switch (error) {
> +		case EFSCORRUPTED:
> +		case EFSBADCRC:
> +		case 0:
> +			break;
> +		default:
> +			return error;
> +		}
> +	}
> +
> +	set_cur_inode(ino);
> +rele:
> +	if (dp)
> +		libxfs_irele(dp);
> +	return error;
> +}
> +
> +/* Walk a directory path to an inode and set the io cursor to that inode. */
> +static int
> +path_walk(
> +	char		*path)
> +{
> +	struct dirpath	*dirpath;
> +	char		*p = path;
> +	xfs_ino_t	rootino = mp->m_sb.sb_rootino;
> +	int		error = 0;
> +
> +	if (*p == '/') {
> +		/* Absolute path, start from the root inode. */
> +		p++;
> +	} else {
> +		/* Relative path, start from current dir. */
> +		if (iocur_top->typ != &typtab[TYP_INODE] ||
> +		    !S_ISDIR(iocur_top->mode))
> +			return ENOTDIR;
> +
> +		rootino = iocur_top->ino;
> +	}
> +
> +	dirpath = path_parse(p);
> +	if (!dirpath)
> +		return ENOMEM;
> +
> +	error = path_navigate(mp, rootino, dirpath);
> +	path_free(dirpath);
> +	return error;
> +}
> +
> +static void
> +path_help(void)
> +{
> +	dbprintf(_(
> +"\n"
> +" Navigate to an inode via directory path.\n"
> +	));
> +}
> +
> +static int
> +path_f(
> +	int		argc,
> +	char		**argv)
> +{
> +	int		c;
> +	int		error;
> +
> +	while ((c = getopt(argc, argv, "")) != -1) {
> +		switch (c) {
> +		default:
> +			path_help();
> +			return 0;
> +		}
> +	}
> +
> +	error = path_walk(argv[optind]);
> +	if (error) {
> +		dbprintf("%s: %s\n", argv[optind], strerror(error));
> +		exitcode = 1;
> +	}
> +
> +	return 0;
> +}
> +
> +static struct cmdinfo path_cmd = {
> +	.name		= "path",
> +	.altname	= NULL,
> +	.cfunc		= path_f,
> +	.argmin		= 1,
> +	.argmax		= 1,
> +	.canpush	= 0,
> +	.args		= "",
> +	.help		= path_help,
> +};
> +
> +void
> +namei_init(void)
> +{
> +	path_cmd.oneline = _("navigate to an inode by path");
> +	add_command(&path_cmd);
> +}
> diff --git a/man/man8/xfs_db.8 b/man/man8/xfs_db.8
> index 55388be6..4df265ec 100644
> --- a/man/man8/xfs_db.8
> +++ b/man/man8/xfs_db.8
> @@ -831,6 +831,10 @@ See the
>  .B print
>  command.
>  .TP
> +.BI "path " dir_path
> +Walk the directory tree to an inode using the supplied path.
> +Absolute and relative paths are supported.
> +.TP
>  .B pop
>  Pop location from the stack.
>  .TP


-- 
chandan

[PATCHSET v3 0/2] xfs_db: add minimal directory navigation

[Darrick J. Wong]

Hi all,

This patchset improves the usability of xfs_db by enabling users to
navigate to inodes by path and to list the contents of directories.

v2: Various cleanups and reorganizing suggested by dchinner
v3: Rebase to 5.10-rc0

If you're going to start using this mess, you probably ought to just
pull from my git trees, which are linked below.

This is an extraordinary way to destroy everything.  Enjoy!
Comments and questions are, as always, welcome.

--D

xfsprogs git tree:
https://git.kernel.org/cgit/linux/kernel/git/djwong/xfsprogs-dev.git/log/?h=xfs_db-directory-navigation

fstests git tree:
https://git.kernel.org/cgit/linux/kernel/git/djwong/xfstests-dev.git/log/?h=xfs_db-directory-navigation
---
 db/Makefile              |    3 
 db/command.c             |    1 
 db/command.h             |    1 
 db/namei.c               |  612 ++++++++++++++++++++++++++++++++++++++++++++++
 libxfs/libxfs_api_defs.h |    1 
 man/man8/xfs_db.8        |   20 ++
 6 files changed, 637 insertions(+), 1 deletion(-)
 create mode 100644 db/namei.c

[PATCH 1/2] xfs_db: add a directory path lookup command

[Darrick J. Wong]

From: Darrick J. Wong <djwong@kernel.org>

Add a command to xfs_db so that we can navigate to inodes by path.

Signed-off-by: Darrick J. Wong <djwong@kernel.org>
---
 db/Makefile       |    3 -
 db/command.c      |    1 
 db/command.h      |    1 
 db/namei.c        |  223 +++++++++++++++++++++++++++++++++++++++++++++++++++++
 man/man8/xfs_db.8 |    4 +
 5 files changed, 231 insertions(+), 1 deletion(-)
 create mode 100644 db/namei.c


diff --git a/db/Makefile b/db/Makefile
index 9d502bf0..beafb105 100644
--- a/db/Makefile
+++ b/db/Makefile
@@ -14,7 +14,8 @@ HFILES = addr.h agf.h agfl.h agi.h attr.h attrshort.h bit.h block.h bmap.h \
 	io.h logformat.h malloc.h metadump.h output.h print.h quit.h sb.h \
 	sig.h strvec.h text.h type.h write.h attrset.h symlink.h fsmap.h \
 	fuzz.h
-CFILES = $(HFILES:.h=.c) btdump.c btheight.c convert.c info.c timelimit.c
+CFILES = $(HFILES:.h=.c) btdump.c btheight.c convert.c info.c namei.c \
+	timelimit.c
 LSRCFILES = xfs_admin.sh xfs_ncheck.sh xfs_metadump.sh
 
 LLDLIBS	= $(LIBXFS) $(LIBXLOG) $(LIBFROG) $(LIBUUID) $(LIBRT) $(LIBPTHREAD)
diff --git a/db/command.c b/db/command.c
index 43828369..02f778b9 100644
--- a/db/command.c
+++ b/db/command.c
@@ -131,6 +131,7 @@ init_commands(void)
 	logformat_init();
 	io_init();
 	metadump_init();
+	namei_init();
 	output_init();
 	print_init();
 	quit_init();
diff --git a/db/command.h b/db/command.h
index 6913c817..498983ff 100644
--- a/db/command.h
+++ b/db/command.h
@@ -33,3 +33,4 @@ extern void		btdump_init(void);
 extern void		info_init(void);
 extern void		btheight_init(void);
 extern void		timelimit_init(void);
+extern void		namei_init(void);
diff --git a/db/namei.c b/db/namei.c
new file mode 100644
index 00000000..eebebe15
--- /dev/null
+++ b/db/namei.c
@@ -0,0 +1,223 @@
+// SPDX-License-Identifier: GPL-2.0-or-later
+/*
+ * Copyright (C) 2021 Oracle.  All Rights Reserved.
+ * Author: Darrick J. Wong <djwong@kernel.org>
+ */
+#include "libxfs.h"
+#include "command.h"
+#include "output.h"
+#include "init.h"
+#include "io.h"
+#include "type.h"
+#include "input.h"
+#include "faddr.h"
+#include "fprint.h"
+#include "field.h"
+#include "inode.h"
+
+/* Path lookup */
+
+/* Key for looking up metadata inodes. */
+struct dirpath {
+	/* Array of string pointers. */
+	char		**path;
+
+	/* Number of strings in path. */
+	unsigned int	depth;
+};
+
+static void
+path_free(
+	struct dirpath	*dirpath)
+{
+	unsigned int	i;
+
+	for (i = 0; i < dirpath->depth; i++)
+		free(dirpath->path[i]);
+	free(dirpath->path);
+	free(dirpath);
+}
+
+/* Chop a freeform string path into a structured path. */
+static struct dirpath *
+path_parse(
+	const char	*path)
+{
+	struct dirpath	*dirpath;
+	const char	*p = path;
+	const char	*endp = path + strlen(path);
+
+	dirpath = calloc(sizeof(*dirpath), 1);
+	if (!dirpath)
+		return NULL;
+
+	while (p < endp) {
+		char		**new_path;
+		const char	*next_slash;
+
+		next_slash = strchr(p, '/');
+		if (next_slash == p) {
+			p++;
+			continue;
+		}
+		if (!next_slash)
+			next_slash = endp;
+
+		new_path = realloc(dirpath->path,
+				(dirpath->depth + 1) * sizeof(char *));
+		if (!new_path) {
+			path_free(dirpath);
+			return NULL;
+		}
+
+		dirpath->path = new_path;
+		dirpath->path[dirpath->depth] = strndup(p, next_slash - p);
+		dirpath->depth++;
+
+		p = next_slash + 1;
+	}
+
+	return dirpath;
+}
+
+/* Given a directory and a structured path, walk the path and set the cursor. */
+static int
+path_navigate(
+	struct xfs_mount	*mp,
+	xfs_ino_t		rootino,
+	struct dirpath		*dirpath)
+{
+	struct xfs_inode	*dp;
+	xfs_ino_t		ino = rootino;
+	unsigned int		i;
+	int			error;
+
+	error = -libxfs_iget(mp, NULL, ino, 0, &dp);
+	if (error)
+		return error;
+
+	for (i = 0; i < dirpath->depth; i++) {
+		struct xfs_name	xname = {
+			.name	= dirpath->path[i],
+			.len	= strlen(dirpath->path[i]),
+		};
+
+		if (!S_ISDIR(VFS_I(dp)->i_mode)) {
+			error = ENOTDIR;
+			goto rele;
+		}
+
+		error = -libxfs_dir_lookup(NULL, dp, &xname, &ino, NULL);
+		if (error)
+			goto rele;
+		if (!xfs_verify_ino(mp, ino)) {
+			error = EFSCORRUPTED;
+			goto rele;
+		}
+
+		libxfs_irele(dp);
+		dp = NULL;
+
+		error = -libxfs_iget(mp, NULL, ino, 0, &dp);
+		switch (error) {
+		case EFSCORRUPTED:
+		case EFSBADCRC:
+		case 0:
+			break;
+		default:
+			return error;
+		}
+	}
+
+	set_cur_inode(ino);
+rele:
+	if (dp)
+		libxfs_irele(dp);
+	return error;
+}
+
+/* Walk a directory path to an inode and set the io cursor to that inode. */
+static int
+path_walk(
+	char		*path)
+{
+	struct dirpath	*dirpath;
+	char		*p = path;
+	xfs_ino_t	rootino = mp->m_sb.sb_rootino;
+	int		error = 0;
+
+	if (*p == '/') {
+		/* Absolute path, start from the root inode. */
+		p++;
+	} else {
+		/* Relative path, start from current dir. */
+		if (iocur_top->typ != &typtab[TYP_INODE] ||
+		    !S_ISDIR(iocur_top->mode))
+			return ENOTDIR;
+
+		rootino = iocur_top->ino;
+	}
+
+	dirpath = path_parse(p);
+	if (!dirpath)
+		return ENOMEM;
+
+	error = path_navigate(mp, rootino, dirpath);
+	if (error)
+		return error;
+
+	path_free(dirpath);
+	return 0;
+}
+
+static void
+path_help(void)
+{
+	dbprintf(_(
+"\n"
+" Navigate to an inode via directory path.\n"
+	));
+}
+
+static int
+path_f(
+	int		argc,
+	char		**argv)
+{
+	int		c;
+	int		error;
+
+	while ((c = getopt(argc, argv, "")) != -1) {
+		switch (c) {
+		default:
+			path_help();
+			return 0;
+		}
+	}
+
+	error = path_walk(argv[optind]);
+	if (error) {
+		dbprintf("%s: %s\n", argv[optind], strerror(error));
+		exitcode = 1;
+	}
+
+	return 0;
+}
+
+static struct cmdinfo path_cmd = {
+	.name		= "path",
+	.altname	= NULL,
+	.cfunc		= path_f,
+	.argmin		= 1,
+	.argmax		= 1,
+	.canpush	= 0,
+	.args		= "",
+	.help		= path_help,
+};
+
+void
+namei_init(void)
+{
+	path_cmd.oneline = _("navigate to an inode by path");
+	add_command(&path_cmd);
+}
diff --git a/man/man8/xfs_db.8 b/man/man8/xfs_db.8
index 55388be6..4df265ec 100644
--- a/man/man8/xfs_db.8
+++ b/man/man8/xfs_db.8
@@ -831,6 +831,10 @@ See the
 .B print
 command.
 .TP
+.BI "path " dir_path
+Walk the directory tree to an inode using the supplied path.
+Absolute and relative paths are supported.
+.TP
 .B pop
 Pop location from the stack.
 .TP

Re: [PATCH 1/2] xfs_db: add a directory path lookup command

[Chandan Babu R]

On 16 Jan 2021 at 06:54, Darrick J. Wong wrote:
> From: Darrick J. Wong <djwong@kernel.org>
>
> Add a command to xfs_db so that we can navigate to inodes by path.
>
> Signed-off-by: Darrick J. Wong <djwong@kernel.org>
> ---
>  db/Makefile       |    3 -
>  db/command.c      |    1
>  db/command.h      |    1
>  db/namei.c        |  223 +++++++++++++++++++++++++++++++++++++++++++++++++++++
>  man/man8/xfs_db.8 |    4 +
>  5 files changed, 231 insertions(+), 1 deletion(-)
>  create mode 100644 db/namei.c
>
>
> diff --git a/db/Makefile b/db/Makefile
> index 9d502bf0..beafb105 100644
> --- a/db/Makefile
> +++ b/db/Makefile
> @@ -14,7 +14,8 @@ HFILES = addr.h agf.h agfl.h agi.h attr.h attrshort.h bit.h block.h bmap.h \
>  	io.h logformat.h malloc.h metadump.h output.h print.h quit.h sb.h \
>  	sig.h strvec.h text.h type.h write.h attrset.h symlink.h fsmap.h \
>  	fuzz.h
> -CFILES = $(HFILES:.h=.c) btdump.c btheight.c convert.c info.c timelimit.c
> +CFILES = $(HFILES:.h=.c) btdump.c btheight.c convert.c info.c namei.c \
> +	timelimit.c
>  LSRCFILES = xfs_admin.sh xfs_ncheck.sh xfs_metadump.sh
>
>  LLDLIBS	= $(LIBXFS) $(LIBXLOG) $(LIBFROG) $(LIBUUID) $(LIBRT) $(LIBPTHREAD)
> diff --git a/db/command.c b/db/command.c
> index 43828369..02f778b9 100644
> --- a/db/command.c
> +++ b/db/command.c
> @@ -131,6 +131,7 @@ init_commands(void)
>  	logformat_init();
>  	io_init();
>  	metadump_init();
> +	namei_init();
>  	output_init();
>  	print_init();
>  	quit_init();
> diff --git a/db/command.h b/db/command.h
> index 6913c817..498983ff 100644
> --- a/db/command.h
> +++ b/db/command.h
> @@ -33,3 +33,4 @@ extern void		btdump_init(void);
>  extern void		info_init(void);
>  extern void		btheight_init(void);
>  extern void		timelimit_init(void);
> +extern void		namei_init(void);
> diff --git a/db/namei.c b/db/namei.c
> new file mode 100644
> index 00000000..eebebe15
> --- /dev/null
> +++ b/db/namei.c
> @@ -0,0 +1,223 @@
> +// SPDX-License-Identifier: GPL-2.0-or-later
> +/*
> + * Copyright (C) 2021 Oracle.  All Rights Reserved.
> + * Author: Darrick J. Wong <djwong@kernel.org>
> + */
> +#include "libxfs.h"
> +#include "command.h"
> +#include "output.h"
> +#include "init.h"
> +#include "io.h"
> +#include "type.h"
> +#include "input.h"
> +#include "faddr.h"
> +#include "fprint.h"
> +#include "field.h"
> +#include "inode.h"
> +
> +/* Path lookup */
> +
> +/* Key for looking up metadata inodes. */
> +struct dirpath {
> +	/* Array of string pointers. */
> +	char		**path;
> +
> +	/* Number of strings in path. */
> +	unsigned int	depth;
> +};
> +
> +static void
> +path_free(
> +	struct dirpath	*dirpath)
> +{
> +	unsigned int	i;
> +
> +	for (i = 0; i < dirpath->depth; i++)
> +		free(dirpath->path[i]);
> +	free(dirpath->path);
> +	free(dirpath);
> +}
> +
> +/* Chop a freeform string path into a structured path. */
> +static struct dirpath *
> +path_parse(
> +	const char	*path)
> +{
> +	struct dirpath	*dirpath;
> +	const char	*p = path;
> +	const char	*endp = path + strlen(path);
> +
> +	dirpath = calloc(sizeof(*dirpath), 1);
> +	if (!dirpath)
> +		return NULL;
> +
> +	while (p < endp) {
> +		char		**new_path;
> +		const char	*next_slash;
> +
> +		next_slash = strchr(p, '/');
> +		if (next_slash == p) {
> +			p++;
> +			continue;
> +		}
> +		if (!next_slash)
> +			next_slash = endp;
> +
> +		new_path = realloc(dirpath->path,
> +				(dirpath->depth + 1) * sizeof(char *));
> +		if (!new_path) {
> +			path_free(dirpath);
> +			return NULL;
> +		}
> +
> +		dirpath->path = new_path;
> +		dirpath->path[dirpath->depth] = strndup(p, next_slash - p);
> +		dirpath->depth++;
> +
> +		p = next_slash + 1;
> +	}
> +
> +	return dirpath;
> +}
> +
> +/* Given a directory and a structured path, walk the path and set the cursor. */
> +static int
> +path_navigate(
> +	struct xfs_mount	*mp,
> +	xfs_ino_t		rootino,
> +	struct dirpath		*dirpath)
> +{
> +	struct xfs_inode	*dp;
> +	xfs_ino_t		ino = rootino;
> +	unsigned int		i;
> +	int			error;
> +
> +	error = -libxfs_iget(mp, NULL, ino, 0, &dp);
> +	if (error)
> +		return error;
> +
> +	for (i = 0; i < dirpath->depth; i++) {
> +		struct xfs_name	xname = {
> +			.name	= dirpath->path[i],
> +			.len	= strlen(dirpath->path[i]),
> +		};
> +
> +		if (!S_ISDIR(VFS_I(dp)->i_mode)) {
> +			error = ENOTDIR;
> +			goto rele;
> +		}
> +
> +		error = -libxfs_dir_lookup(NULL, dp, &xname, &ino, NULL);
> +		if (error)
> +			goto rele;
> +		if (!xfs_verify_ino(mp, ino)) {
> +			error = EFSCORRUPTED;
> +			goto rele;
> +		}
> +
> +		libxfs_irele(dp);
> +		dp = NULL;
> +
> +		error = -libxfs_iget(mp, NULL, ino, 0, &dp);
> +		switch (error) {
> +		case EFSCORRUPTED:
> +		case EFSBADCRC:
> +		case 0:
> +			break;
> +		default:
> +			return error;
> +		}
> +	}
> +
> +	set_cur_inode(ino);
> +rele:
> +	if (dp)
> +		libxfs_irele(dp);
> +	return error;
> +}
> +
> +/* Walk a directory path to an inode and set the io cursor to that inode. */
> +static int
> +path_walk(
> +	char		*path)
> +{
> +	struct dirpath	*dirpath;
> +	char		*p = path;
> +	xfs_ino_t	rootino = mp->m_sb.sb_rootino;
> +	int		error = 0;
> +
> +	if (*p == '/') {
> +		/* Absolute path, start from the root inode. */
> +		p++;
> +	} else {
> +		/* Relative path, start from current dir. */
> +		if (iocur_top->typ != &typtab[TYP_INODE] ||
> +		    !S_ISDIR(iocur_top->mode))
> +			return ENOTDIR;
> +
> +		rootino = iocur_top->ino;
> +	}
> +
> +	dirpath = path_parse(p);
> +	if (!dirpath)
> +		return ENOMEM;
> +
> +	error = path_navigate(mp, rootino, dirpath);
> +	if (error)
> +		return error;

Memory pointed by dirpath (and its members) is not freed if the call to
path_navigate() returns a non-zero error value.

> +
> +	path_free(dirpath);
> +	return 0;
> +}
> +
> +static void
> +path_help(void)
> +{
> +	dbprintf(_(
> +"\n"
> +" Navigate to an inode via directory path.\n"
> +	));
> +}
> +
> +static int
> +path_f(
> +	int		argc,
> +	char		**argv)
> +{
> +	int		c;
> +	int		error;
> +
> +	while ((c = getopt(argc, argv, "")) != -1) {
> +		switch (c) {
> +		default:
> +			path_help();
> +			return 0;
> +		}
> +	}
> +
> +	error = path_walk(argv[optind]);
> +	if (error) {
> +		dbprintf("%s: %s\n", argv[optind], strerror(error));
> +		exitcode = 1;
> +	}
> +
> +	return 0;
> +}
> +
> +static struct cmdinfo path_cmd = {
> +	.name		= "path",
> +	.altname	= NULL,
> +	.cfunc		= path_f,
> +	.argmin		= 1,
> +	.argmax		= 1,
> +	.canpush	= 0,
> +	.args		= "",
> +	.help		= path_help,
> +};
> +
> +void
> +namei_init(void)
> +{
> +	path_cmd.oneline = _("navigate to an inode by path");
> +	add_command(&path_cmd);
> +}
> diff --git a/man/man8/xfs_db.8 b/man/man8/xfs_db.8
> index 55388be6..4df265ec 100644
> --- a/man/man8/xfs_db.8
> +++ b/man/man8/xfs_db.8
> @@ -831,6 +831,10 @@ See the
>  .B print
>  command.
>  .TP
> +.BI "path " dir_path
> +Walk the directory tree to an inode using the supplied path.
> +Absolute and relative paths are supported.
> +.TP
>  .B pop
>  Pop location from the stack.
>  .TP


--
chandan

Re: [PATCH 1/2] xfs_db: add a directory path lookup command

[Darrick J. Wong]

On Wed, Jan 20, 2021 at 06:05:35PM +0530, Chandan Babu R wrote:
> 
> On 16 Jan 2021 at 06:54, Darrick J. Wong wrote:
> > From: Darrick J. Wong <djwong@kernel.org>
> >
> > Add a command to xfs_db so that we can navigate to inodes by path.
> >
> > Signed-off-by: Darrick J. Wong <djwong@kernel.org>
> > ---
> >  db/Makefile       |    3 -
> >  db/command.c      |    1
> >  db/command.h      |    1
> >  db/namei.c        |  223 +++++++++++++++++++++++++++++++++++++++++++++++++++++
> >  man/man8/xfs_db.8 |    4 +
> >  5 files changed, 231 insertions(+), 1 deletion(-)
> >  create mode 100644 db/namei.c
> >
> >
> > diff --git a/db/Makefile b/db/Makefile
> > index 9d502bf0..beafb105 100644
> > --- a/db/Makefile
> > +++ b/db/Makefile
> > @@ -14,7 +14,8 @@ HFILES = addr.h agf.h agfl.h agi.h attr.h attrshort.h bit.h block.h bmap.h \
> >  	io.h logformat.h malloc.h metadump.h output.h print.h quit.h sb.h \
> >  	sig.h strvec.h text.h type.h write.h attrset.h symlink.h fsmap.h \
> >  	fuzz.h
> > -CFILES = $(HFILES:.h=.c) btdump.c btheight.c convert.c info.c timelimit.c
> > +CFILES = $(HFILES:.h=.c) btdump.c btheight.c convert.c info.c namei.c \
> > +	timelimit.c
> >  LSRCFILES = xfs_admin.sh xfs_ncheck.sh xfs_metadump.sh
> >
> >  LLDLIBS	= $(LIBXFS) $(LIBXLOG) $(LIBFROG) $(LIBUUID) $(LIBRT) $(LIBPTHREAD)
> > diff --git a/db/command.c b/db/command.c
> > index 43828369..02f778b9 100644
> > --- a/db/command.c
> > +++ b/db/command.c
> > @@ -131,6 +131,7 @@ init_commands(void)
> >  	logformat_init();
> >  	io_init();
> >  	metadump_init();
> > +	namei_init();
> >  	output_init();
> >  	print_init();
> >  	quit_init();
> > diff --git a/db/command.h b/db/command.h
> > index 6913c817..498983ff 100644
> > --- a/db/command.h
> > +++ b/db/command.h
> > @@ -33,3 +33,4 @@ extern void		btdump_init(void);
> >  extern void		info_init(void);
> >  extern void		btheight_init(void);
> >  extern void		timelimit_init(void);
> > +extern void		namei_init(void);
> > diff --git a/db/namei.c b/db/namei.c
> > new file mode 100644
> > index 00000000..eebebe15
> > --- /dev/null
> > +++ b/db/namei.c
> > @@ -0,0 +1,223 @@

<snip some of this out>

> > +/* Walk a directory path to an inode and set the io cursor to that inode. */
> > +static int
> > +path_walk(
> > +	char		*path)
> > +{
> > +	struct dirpath	*dirpath;
> > +	char		*p = path;
> > +	xfs_ino_t	rootino = mp->m_sb.sb_rootino;
> > +	int		error = 0;
> > +
> > +	if (*p == '/') {
> > +		/* Absolute path, start from the root inode. */
> > +		p++;
> > +	} else {
> > +		/* Relative path, start from current dir. */
> > +		if (iocur_top->typ != &typtab[TYP_INODE] ||
> > +		    !S_ISDIR(iocur_top->mode))
> > +			return ENOTDIR;
> > +
> > +		rootino = iocur_top->ino;
> > +	}
> > +
> > +	dirpath = path_parse(p);
> > +	if (!dirpath)
> > +		return ENOMEM;
> > +
> > +	error = path_navigate(mp, rootino, dirpath);
> > +	if (error)
> > +		return error;
> 
> Memory pointed by dirpath (and its members) is not freed if the call to
> path_navigate() returns a non-zero error value.

Good catch, thanks!

--D

[PATCH v3 0/2] xfs_db: add minimal directory navigation

[Darrick J. Wong]

Hi all,

Improve the usability of xfs_db by enabling users to navigate to inodes
by path and to list the contents of directories.

v2: Various cleanups and reorganizing suggested by dchinner
v3: Rebase to 5.10-rc0

If you're going to start using this mess, you probably ought to just
pull from my git trees, which are linked below.

This is an extraordinary way to destroy everything.  Enjoy!
Comments and questions are, as always, welcome.

--D

xfsprogs git tree:
https://git.kernel.org/cgit/linux/kernel/git/djwong/xfsprogs-dev.git/log/?h=xfs_db-directory-navigation

fstests git tree:
https://git.kernel.org/cgit/linux/kernel/git/djwong/xfstests-dev.git/log/?h=xfs_db-directory-navigation
---
 db/Makefile              |    3 
 db/command.c             |    1 
 db/command.h             |    1 
 db/namei.c               |  612 ++++++++++++++++++++++++++++++++++++++++++++++
 libxfs/libxfs_api_defs.h |    1 
 man/man8/xfs_db.8        |   20 ++
 6 files changed, 637 insertions(+), 1 deletion(-)
 create mode 100644 db/namei.c

[PATCH 1/2] xfs_db: add a directory path lookup command

[Darrick J. Wong]

From: Darrick J. Wong <darrick.wong@oracle.com>

Add a command to xfs_db so that we can navigate to inodes by path.

Signed-off-by: Darrick J. Wong <darrick.wong@oracle.com>
---
 db/Makefile       |    3 -
 db/command.c      |    1 
 db/command.h      |    1 
 db/namei.c        |  223 +++++++++++++++++++++++++++++++++++++++++++++++++++++
 man/man8/xfs_db.8 |    4 +
 5 files changed, 231 insertions(+), 1 deletion(-)
 create mode 100644 db/namei.c


diff --git a/db/Makefile b/db/Makefile
index 9d502bf0d0d6..beafb1058269 100644
--- a/db/Makefile
+++ b/db/Makefile
@@ -14,7 +14,8 @@ HFILES = addr.h agf.h agfl.h agi.h attr.h attrshort.h bit.h block.h bmap.h \
 	io.h logformat.h malloc.h metadump.h output.h print.h quit.h sb.h \
 	sig.h strvec.h text.h type.h write.h attrset.h symlink.h fsmap.h \
 	fuzz.h
-CFILES = $(HFILES:.h=.c) btdump.c btheight.c convert.c info.c timelimit.c
+CFILES = $(HFILES:.h=.c) btdump.c btheight.c convert.c info.c namei.c \
+	timelimit.c
 LSRCFILES = xfs_admin.sh xfs_ncheck.sh xfs_metadump.sh
 
 LLDLIBS	= $(LIBXFS) $(LIBXLOG) $(LIBFROG) $(LIBUUID) $(LIBRT) $(LIBPTHREAD)
diff --git a/db/command.c b/db/command.c
index 438283699b2e..02f778b9316b 100644
--- a/db/command.c
+++ b/db/command.c
@@ -131,6 +131,7 @@ init_commands(void)
 	logformat_init();
 	io_init();
 	metadump_init();
+	namei_init();
 	output_init();
 	print_init();
 	quit_init();
diff --git a/db/command.h b/db/command.h
index 6913c8171fe1..498983ff92fa 100644
--- a/db/command.h
+++ b/db/command.h
@@ -33,3 +33,4 @@ extern void		btdump_init(void);
 extern void		info_init(void);
 extern void		btheight_init(void);
 extern void		timelimit_init(void);
+extern void		namei_init(void);
diff --git a/db/namei.c b/db/namei.c
new file mode 100644
index 000000000000..13ae7f7d116b
--- /dev/null
+++ b/db/namei.c
@@ -0,0 +1,223 @@
+// SPDX-License-Identifier: GPL-2.0-or-later
+/*
+ * Copyright (C) 2020 Oracle.  All Rights Reserved.
+ * Author: Darrick J. Wong <darrick.wong@oracle.com>
+ */
+#include "libxfs.h"
+#include "command.h"
+#include "output.h"
+#include "init.h"
+#include "io.h"
+#include "type.h"
+#include "input.h"
+#include "faddr.h"
+#include "fprint.h"
+#include "field.h"
+#include "inode.h"
+
+/* Path lookup */
+
+/* Key for looking up metadata inodes. */
+struct dirpath {
+	/* Array of string pointers. */
+	char		**path;
+
+	/* Number of strings in path. */
+	unsigned int	depth;
+};
+
+static void
+path_free(
+	struct dirpath	*dirpath)
+{
+	unsigned int	i;
+
+	for (i = 0; i < dirpath->depth; i++)
+		free(dirpath->path[i]);
+	free(dirpath->path);
+	free(dirpath);
+}
+
+/* Chop a freeform string path into a structured path. */
+static struct dirpath *
+path_parse(
+	const char	*path)
+{
+	struct dirpath	*dirpath;
+	const char	*p = path;
+	const char	*endp = path + strlen(path);
+
+	dirpath = calloc(sizeof(*dirpath), 1);
+	if (!dirpath)
+		return NULL;
+
+	while (p < endp) {
+		char		**new_path;
+		const char	*next_slash;
+
+		next_slash = strchr(p, '/');
+		if (next_slash == p) {
+			p++;
+			continue;
+		}
+		if (!next_slash)
+			next_slash = endp;
+
+		new_path = realloc(dirpath->path,
+				(dirpath->depth + 1) * sizeof(char *));
+		if (!new_path) {
+			path_free(dirpath);
+			return NULL;
+		}
+
+		dirpath->path = new_path;
+		dirpath->path[dirpath->depth] = strndup(p, next_slash - p);
+		dirpath->depth++;
+
+		p = next_slash + 1;
+	}
+
+	return dirpath;
+}
+
+/* Given a directory and a structured path, walk the path and set the cursor. */
+static int
+path_navigate(
+	struct xfs_mount	*mp,
+	xfs_ino_t		rootino,
+	struct dirpath		*dirpath)
+{
+	struct xfs_inode	*dp;
+	xfs_ino_t		ino = rootino;
+	unsigned int		i;
+	int			error;
+
+	error = -libxfs_iget(mp, NULL, ino, 0, &dp);
+	if (error)
+		return error;
+
+	for (i = 0; i < dirpath->depth; i++) {
+		struct xfs_name	xname = {
+			.name	= dirpath->path[i],
+			.len	= strlen(dirpath->path[i]),
+		};
+
+		if (!S_ISDIR(VFS_I(dp)->i_mode)) {
+			error = ENOTDIR;
+			goto rele;
+		}
+
+		error = -libxfs_dir_lookup(NULL, dp, &xname, &ino, NULL);
+		if (error)
+			goto rele;
+		if (!xfs_verify_ino(mp, ino)) {
+			error = EFSCORRUPTED;
+			goto rele;
+		}
+
+		libxfs_irele(dp);
+		dp = NULL;
+
+		error = -libxfs_iget(mp, NULL, ino, 0, &dp);
+		switch (error) {
+		case EFSCORRUPTED:
+		case EFSBADCRC:
+		case 0:
+			break;
+		default:
+			return error;
+		}
+	}
+
+	set_cur_inode(ino);
+rele:
+	if (dp)
+		libxfs_irele(dp);
+	return error;
+}
+
+/* Walk a directory path to an inode and set the io cursor to that inode. */
+static int
+path_walk(
+	char		*path)
+{
+	struct dirpath	*dirpath;
+	char		*p = path;
+	xfs_ino_t	rootino = mp->m_sb.sb_rootino;
+	int		error = 0;
+
+	if (*p == '/') {
+		/* Absolute path, start from the root inode. */
+		p++;
+	} else {
+		/* Relative path, start from current dir. */
+		if (iocur_top->typ != &typtab[TYP_INODE] ||
+		    !S_ISDIR(iocur_top->mode))
+			return ENOTDIR;
+
+		rootino = iocur_top->ino;
+	}
+
+	dirpath = path_parse(p);
+	if (!dirpath)
+		return ENOMEM;
+
+	error = path_navigate(mp, rootino, dirpath);
+	if (error)
+		return error;
+
+	path_free(dirpath);
+	return 0;
+}
+
+static void
+path_help(void)
+{
+	dbprintf(_(
+"\n"
+" Navigate to an inode via directory path.\n"
+	));
+}
+
+static int
+path_f(
+	int		argc,
+	char		**argv)
+{
+	int		c;
+	int		error;
+
+	while ((c = getopt(argc, argv, "")) != -1) {
+		switch (c) {
+		default:
+			path_help();
+			return 0;
+		}
+	}
+
+	error = path_walk(argv[optind]);
+	if (error) {
+		dbprintf("%s: %s\n", argv[optind], strerror(error));
+		exitcode = 1;
+	}
+
+	return 0;
+}
+
+static struct cmdinfo path_cmd = {
+	.name		= "path",
+	.altname	= NULL,
+	.cfunc		= path_f,
+	.argmin		= 1,
+	.argmax		= 1,
+	.canpush	= 0,
+	.args		= "",
+	.help		= path_help,
+};
+
+void
+namei_init(void)
+{
+	path_cmd.oneline = _("navigate to an inode by path");
+	add_command(&path_cmd);
+}
diff --git a/man/man8/xfs_db.8 b/man/man8/xfs_db.8
index 55388be68b93..4df265ecd59e 100644
--- a/man/man8/xfs_db.8
+++ b/man/man8/xfs_db.8
@@ -831,6 +831,10 @@ See the
 .B print
 command.
 .TP
+.BI "path " dir_path
+Walk the directory tree to an inode using the supplied path.
+Absolute and relative paths are supported.
+.TP
 .B pop
 Pop location from the stack.
 .TP

Re: [PATCH 1/2] xfs_db: add a directory path lookup command

[Christoph Hellwig]

Looks good,

Reviewed-by: Christoph Hellwig <hch@lst.de>

[PATCH v2 0/2] xfs_db: add minimal directory navigation

[Darrick J. Wong]

Hi all,

Improve the usability of xfs_db by enabling users to navigate to inodes
by path and to list the contents of directories.

v2: Various cleanups and reorganizing suggested by dchinner

If you're going to start using this mess, you probably ought to just
pull from my git trees, which are linked below.

This is an extraordinary way to destroy everything.  Enjoy!
Comments and questions are, as always, welcome.

--D

xfsprogs git tree:
https://git.kernel.org/cgit/linux/kernel/git/djwong/xfsprogs-dev.git/log/?h=xfs_db-directory-navigation

fstests git tree:
https://git.kernel.org/cgit/linux/kernel/git/djwong/xfstests-dev.git/log/?h=xfs_db-directory-navigation
---
 db/Makefile              |    2 
 db/command.c             |    1 
 db/command.h             |    1 
 db/namei.c               |  612 ++++++++++++++++++++++++++++++++++++++++++++++
 libxfs/libxfs_api_defs.h |    1 
 man/man8/xfs_db.8        |   20 ++
 6 files changed, 636 insertions(+), 1 deletion(-)
 create mode 100644 db/namei.c

[PATCH 1/2] xfs_db: add a directory path lookup command

[Darrick J. Wong]

From: Darrick J. Wong <darrick.wong@oracle.com>

Add a command to xfs_db so that we can navigate to inodes by path.

Signed-off-by: Darrick J. Wong <darrick.wong@oracle.com>
---
 db/Makefile       |    2 
 db/command.c      |    1 
 db/command.h      |    1 
 db/namei.c        |  223 +++++++++++++++++++++++++++++++++++++++++++++++++++++
 man/man8/xfs_db.8 |    4 +
 5 files changed, 230 insertions(+), 1 deletion(-)
 create mode 100644 db/namei.c


diff --git a/db/Makefile b/db/Makefile
index 9bd9bf514f5d..67908a2c3c98 100644
--- a/db/Makefile
+++ b/db/Makefile
@@ -14,7 +14,7 @@ HFILES = addr.h agf.h agfl.h agi.h attr.h attrshort.h bit.h block.h bmap.h \
 	io.h logformat.h malloc.h metadump.h output.h print.h quit.h sb.h \
 	sig.h strvec.h text.h type.h write.h attrset.h symlink.h fsmap.h \
 	fuzz.h
-CFILES = $(HFILES:.h=.c) btdump.c btheight.c convert.c info.c
+CFILES = $(HFILES:.h=.c) btdump.c btheight.c convert.c info.c namei.c
 LSRCFILES = xfs_admin.sh xfs_ncheck.sh xfs_metadump.sh
 
 LLDLIBS	= $(LIBXFS) $(LIBXLOG) $(LIBFROG) $(LIBUUID) $(LIBRT) $(LIBPTHREAD)
diff --git a/db/command.c b/db/command.c
index 0fb44efaec59..053097742b12 100644
--- a/db/command.c
+++ b/db/command.c
@@ -131,6 +131,7 @@ init_commands(void)
 	logformat_init();
 	io_init();
 	metadump_init();
+	namei_init();
 	output_init();
 	print_init();
 	quit_init();
diff --git a/db/command.h b/db/command.h
index b8499de0be17..bf130e63c85c 100644
--- a/db/command.h
+++ b/db/command.h
@@ -32,3 +32,4 @@ extern void		convert_init(void);
 extern void		btdump_init(void);
 extern void		info_init(void);
 extern void		btheight_init(void);
+extern void		namei_init(void);
diff --git a/db/namei.c b/db/namei.c
new file mode 100644
index 000000000000..13ae7f7d116b
--- /dev/null
+++ b/db/namei.c
@@ -0,0 +1,223 @@
+// SPDX-License-Identifier: GPL-2.0-or-later
+/*
+ * Copyright (C) 2020 Oracle.  All Rights Reserved.
+ * Author: Darrick J. Wong <darrick.wong@oracle.com>
+ */
+#include "libxfs.h"
+#include "command.h"
+#include "output.h"
+#include "init.h"
+#include "io.h"
+#include "type.h"
+#include "input.h"
+#include "faddr.h"
+#include "fprint.h"
+#include "field.h"
+#include "inode.h"
+
+/* Path lookup */
+
+/* Key for looking up metadata inodes. */
+struct dirpath {
+	/* Array of string pointers. */
+	char		**path;
+
+	/* Number of strings in path. */
+	unsigned int	depth;
+};
+
+static void
+path_free(
+	struct dirpath	*dirpath)
+{
+	unsigned int	i;
+
+	for (i = 0; i < dirpath->depth; i++)
+		free(dirpath->path[i]);
+	free(dirpath->path);
+	free(dirpath);
+}
+
+/* Chop a freeform string path into a structured path. */
+static struct dirpath *
+path_parse(
+	const char	*path)
+{
+	struct dirpath	*dirpath;
+	const char	*p = path;
+	const char	*endp = path + strlen(path);
+
+	dirpath = calloc(sizeof(*dirpath), 1);
+	if (!dirpath)
+		return NULL;
+
+	while (p < endp) {
+		char		**new_path;
+		const char	*next_slash;
+
+		next_slash = strchr(p, '/');
+		if (next_slash == p) {
+			p++;
+			continue;
+		}
+		if (!next_slash)
+			next_slash = endp;
+
+		new_path = realloc(dirpath->path,
+				(dirpath->depth + 1) * sizeof(char *));
+		if (!new_path) {
+			path_free(dirpath);
+			return NULL;
+		}
+
+		dirpath->path = new_path;
+		dirpath->path[dirpath->depth] = strndup(p, next_slash - p);
+		dirpath->depth++;
+
+		p = next_slash + 1;
+	}
+
+	return dirpath;
+}
+
+/* Given a directory and a structured path, walk the path and set the cursor. */
+static int
+path_navigate(
+	struct xfs_mount	*mp,
+	xfs_ino_t		rootino,
+	struct dirpath		*dirpath)
+{
+	struct xfs_inode	*dp;
+	xfs_ino_t		ino = rootino;
+	unsigned int		i;
+	int			error;
+
+	error = -libxfs_iget(mp, NULL, ino, 0, &dp);
+	if (error)
+		return error;
+
+	for (i = 0; i < dirpath->depth; i++) {
+		struct xfs_name	xname = {
+			.name	= dirpath->path[i],
+			.len	= strlen(dirpath->path[i]),
+		};
+
+		if (!S_ISDIR(VFS_I(dp)->i_mode)) {
+			error = ENOTDIR;
+			goto rele;
+		}
+
+		error = -libxfs_dir_lookup(NULL, dp, &xname, &ino, NULL);
+		if (error)
+			goto rele;
+		if (!xfs_verify_ino(mp, ino)) {
+			error = EFSCORRUPTED;
+			goto rele;
+		}
+
+		libxfs_irele(dp);
+		dp = NULL;
+
+		error = -libxfs_iget(mp, NULL, ino, 0, &dp);
+		switch (error) {
+		case EFSCORRUPTED:
+		case EFSBADCRC:
+		case 0:
+			break;
+		default:
+			return error;
+		}
+	}
+
+	set_cur_inode(ino);
+rele:
+	if (dp)
+		libxfs_irele(dp);
+	return error;
+}
+
+/* Walk a directory path to an inode and set the io cursor to that inode. */
+static int
+path_walk(
+	char		*path)
+{
+	struct dirpath	*dirpath;
+	char		*p = path;
+	xfs_ino_t	rootino = mp->m_sb.sb_rootino;
+	int		error = 0;
+
+	if (*p == '/') {
+		/* Absolute path, start from the root inode. */
+		p++;
+	} else {
+		/* Relative path, start from current dir. */
+		if (iocur_top->typ != &typtab[TYP_INODE] ||
+		    !S_ISDIR(iocur_top->mode))
+			return ENOTDIR;
+
+		rootino = iocur_top->ino;
+	}
+
+	dirpath = path_parse(p);
+	if (!dirpath)
+		return ENOMEM;
+
+	error = path_navigate(mp, rootino, dirpath);
+	if (error)
+		return error;
+
+	path_free(dirpath);
+	return 0;
+}
+
+static void
+path_help(void)
+{
+	dbprintf(_(
+"\n"
+" Navigate to an inode via directory path.\n"
+	));
+}
+
+static int
+path_f(
+	int		argc,
+	char		**argv)
+{
+	int		c;
+	int		error;
+
+	while ((c = getopt(argc, argv, "")) != -1) {
+		switch (c) {
+		default:
+			path_help();
+			return 0;
+		}
+	}
+
+	error = path_walk(argv[optind]);
+	if (error) {
+		dbprintf("%s: %s\n", argv[optind], strerror(error));
+		exitcode = 1;
+	}
+
+	return 0;
+}
+
+static struct cmdinfo path_cmd = {
+	.name		= "path",
+	.altname	= NULL,
+	.cfunc		= path_f,
+	.argmin		= 1,
+	.argmax		= 1,
+	.canpush	= 0,
+	.args		= "",
+	.help		= path_help,
+};
+
+void
+namei_init(void)
+{
+	path_cmd.oneline = _("navigate to an inode by path");
+	add_command(&path_cmd);
+}
diff --git a/man/man8/xfs_db.8 b/man/man8/xfs_db.8
index 7f73d458cf76..d67e108a706a 100644
--- a/man/man8/xfs_db.8
+++ b/man/man8/xfs_db.8
@@ -831,6 +831,10 @@ See the
 .B print
 command.
 .TP
+.BI "path " dir_path
+Walk the directory tree to an inode using the supplied path.
+Absolute and relative paths are supported.
+.TP
 .B pop
 Pop location from the stack.
 .TP

[PATCH 0/2] xfs_db: add minimal directory navigation

[Darrick J. Wong]

Hi all,

Improve the usability of xfs_db by enabling users to navigate to inodes
by path and to list the contents of directories.

If you're going to start using this mess, you probably ought to just
pull from my git trees, which are linked below.

This is an extraordinary way to destroy everything.  Enjoy!
Comments and questions are, as always, welcome.

--D

xfsprogs git tree:
https://git.kernel.org/cgit/linux/kernel/git/djwong/xfsprogs-dev.git/log/?h=xfs_db-directory-navigation

fstests git tree:
https://git.kernel.org/cgit/linux/kernel/git/djwong/xfstests-dev.git/log/?h=xfs_db-directory-navigation
---
 db/Makefile              |    2 
 db/command.c             |    1 
 db/command.h             |    1 
 db/namei.c               |  608 ++++++++++++++++++++++++++++++++++++++++++++++
 libxfs/libxfs_api_defs.h |    1 
 man/man8/xfs_db.8        |   18 +
 6 files changed, 630 insertions(+), 1 deletion(-)
 create mode 100644 db/namei.c

[PATCH 1/2] xfs_db: add a directory path lookup command

[Darrick J. Wong]

From: Darrick J. Wong <darrick.wong@oracle.com>

Add a command to xfs_db so that we can navigate to inodes by path.

Signed-off-by: Darrick J. Wong <darrick.wong@oracle.com>
---
 db/Makefile       |    2 
 db/command.c      |    1 
 db/command.h      |    1 
 db/namei.c        |  228 +++++++++++++++++++++++++++++++++++++++++++++++++++++
 man/man8/xfs_db.8 |    4 +
 5 files changed, 235 insertions(+), 1 deletion(-)
 create mode 100644 db/namei.c


diff --git a/db/Makefile b/db/Makefile
index 9bd9bf514f5d..67908a2c3c98 100644
--- a/db/Makefile
+++ b/db/Makefile
@@ -14,7 +14,7 @@ HFILES = addr.h agf.h agfl.h agi.h attr.h attrshort.h bit.h block.h bmap.h \
 	io.h logformat.h malloc.h metadump.h output.h print.h quit.h sb.h \
 	sig.h strvec.h text.h type.h write.h attrset.h symlink.h fsmap.h \
 	fuzz.h
-CFILES = $(HFILES:.h=.c) btdump.c btheight.c convert.c info.c
+CFILES = $(HFILES:.h=.c) btdump.c btheight.c convert.c info.c namei.c
 LSRCFILES = xfs_admin.sh xfs_ncheck.sh xfs_metadump.sh
 
 LLDLIBS	= $(LIBXFS) $(LIBXLOG) $(LIBFROG) $(LIBUUID) $(LIBRT) $(LIBPTHREAD)
diff --git a/db/command.c b/db/command.c
index 0fb44efaec59..053097742b12 100644
--- a/db/command.c
+++ b/db/command.c
@@ -131,6 +131,7 @@ init_commands(void)
 	logformat_init();
 	io_init();
 	metadump_init();
+	namei_init();
 	output_init();
 	print_init();
 	quit_init();
diff --git a/db/command.h b/db/command.h
index b8499de0be17..bf130e63c85c 100644
--- a/db/command.h
+++ b/db/command.h
@@ -32,3 +32,4 @@ extern void		convert_init(void);
 extern void		btdump_init(void);
 extern void		info_init(void);
 extern void		btheight_init(void);
+extern void		namei_init(void);
diff --git a/db/namei.c b/db/namei.c
new file mode 100644
index 000000000000..3c9889d62338
--- /dev/null
+++ b/db/namei.c
@@ -0,0 +1,228 @@
+// SPDX-License-Identifier: GPL-2.0-or-later
+/*
+ * Copyright (C) 2020 Oracle.  All Rights Reserved.
+ * Author: Darrick J. Wong <darrick.wong@oracle.com>
+ */
+#include "libxfs.h"
+#include "command.h"
+#include "output.h"
+#include "init.h"
+#include "io.h"
+#include "type.h"
+#include "input.h"
+#include "faddr.h"
+#include "fprint.h"
+#include "field.h"
+#include "inode.h"
+
+/* Path lookup */
+
+/* Key for looking up metadata inodes. */
+struct dirpath {
+	/* Array of string pointers. */
+	char		**path;
+
+	/* Number of strings in path. */
+	unsigned int	depth;
+};
+
+static void
+path_free(
+	struct dirpath	*dirpath)
+{
+	unsigned int	i;
+
+	for (i = 0; i < dirpath->depth; i++)
+		free(dirpath->path[i]);
+	free(dirpath->path);
+	free(dirpath);
+}
+
+/* Chop a freeform string path into a structured path. */
+static struct dirpath *
+path_parse(
+	const char	*path)
+{
+	struct dirpath	*dirpath;
+	const char	*p = path;
+	const char	*endp = path + strlen(path);
+
+	dirpath = calloc(sizeof(*dirpath), 1);
+	if (!dirpath)
+		return NULL;
+
+	while (p < endp) {
+		char		**new_path;
+		const char	*next_slash;
+
+		next_slash = strchr(p, '/');
+		if (next_slash == p) {
+			p++;
+			continue;
+		}
+		if (!next_slash)
+			next_slash = endp;
+
+		new_path = realloc(dirpath->path,
+				(dirpath->depth + 1) * sizeof(char *));
+		if (!new_path) {
+			path_free(dirpath);
+			return NULL;
+		}
+
+		dirpath->path = new_path;
+		dirpath->path[dirpath->depth] = strndup(p, next_slash - p);
+		dirpath->depth++;
+
+		p = next_slash + 1;
+	}
+
+	return dirpath;
+}
+
+/* Given a directory and a structured path, walk the path and set the cursor. */
+static int
+path_navigate(
+	struct xfs_mount	*mp,
+	xfs_ino_t		rootino,
+	struct dirpath		*dirpath)
+{
+	struct xfs_inode	*dp;
+	xfs_ino_t		ino = rootino;
+	unsigned int		i;
+	int			error;
+
+	error = -libxfs_iget(mp, NULL, ino, 0, &dp);
+	if (error)
+		return error;
+
+	for (i = 0; i < dirpath->depth; i++) {
+		struct xfs_name	xname = {
+			.name	= dirpath->path[i],
+			.len	= strlen(dirpath->path[i]),
+		};
+
+		if (!S_ISDIR(VFS_I(dp)->i_mode)) {
+			error = ENOTDIR;
+			goto rele;
+		}
+
+		error = -libxfs_dir_lookup(NULL, dp, &xname, &ino, NULL);
+		if (error)
+			goto rele;
+		if (!xfs_verify_ino(mp, ino)) {
+			error = EFSCORRUPTED;
+			goto rele;
+		}
+
+		libxfs_irele(dp);
+		dp = NULL;
+
+		error = -libxfs_iget(mp, NULL, ino, 0, &dp);
+		switch (error) {
+		case EFSCORRUPTED:
+		case EFSBADCRC:
+		case 0:
+			break;
+		default:
+			return error;
+		}
+	}
+
+	set_cur_inode(ino);
+rele:
+	if (dp)
+		libxfs_irele(dp);
+	return error;
+}
+
+/* Walk a directory path to an inode and set the io cursor to that inode. */
+static int
+path_walk(
+	char		*path)
+{
+	struct dirpath	*dirpath;
+	char		*p = path;
+	xfs_ino_t	rootino = mp->m_sb.sb_rootino;
+	int		ret = 0;
+
+	if (*p == '/') {
+		/* Absolute path, start from the root inode. */
+		p++;
+	} else {
+		/* Relative path, start from current dir. */
+		if (iocur_top->typ != &typtab[TYP_INODE]) {
+			dbprintf(_("current object is not an inode.\n"));
+			return -1;
+		}
+
+		if (!S_ISDIR(iocur_top->mode)) {
+			dbprintf(_("current inode %llu is not a directory.\n"),
+					(unsigned long long)iocur_top->ino);
+			return -1;
+		}
+		rootino = iocur_top->ino;
+	}
+
+	dirpath = path_parse(p);
+	if (!dirpath) {
+		dbprintf(_("%s: not enough memory to parse.\n"), path);
+		return -1;
+	}
+
+	ret = path_navigate(mp, rootino, dirpath);
+	if (ret) {
+		dbprintf(_("%s: %s\n"), path, strerror(ret));
+		ret = -1;
+	}
+
+	path_free(dirpath);
+	return ret;
+}
+
+static void
+path_help(void)
+{
+	dbprintf(_(
+"\n"
+" Navigate to an inode via directory path.\n"
+	));
+}
+
+static int
+path_f(
+	int		argc,
+	char		**argv)
+{
+	int		c;
+
+	while ((c = getopt(argc, argv, "")) != -1) {
+		switch (c) {
+		default:
+			path_help();
+			return 0;
+		}
+	}
+
+	if (path_walk(argv[optind]))
+		exitcode = 1;
+	return 0;
+}
+
+static const cmdinfo_t path_cmd = {
+	.name		= "path",
+	.altname	= NULL,
+	.cfunc		= path_f,
+	.argmin		= 1,
+	.argmax		= 1,
+	.canpush	= 0,
+	.args		= "",
+	.oneline	= N_("navigate to an inode by path"),
+	.help		= path_help,
+};
+
+void
+namei_init(void)
+{
+	add_command(&path_cmd);
+}
diff --git a/man/man8/xfs_db.8 b/man/man8/xfs_db.8
index 7f73d458cf76..d67e108a706a 100644
--- a/man/man8/xfs_db.8
+++ b/man/man8/xfs_db.8
@@ -831,6 +831,10 @@ See the
 .B print
 command.
 .TP
+.BI "path " dir_path
+Walk the directory tree to an inode using the supplied path.
+Absolute and relative paths are supported.
+.TP
 .B pop
 Pop location from the stack.
 .TP

Re: [PATCH 1/2] xfs_db: add a directory path lookup command

[Dave Chinner]

On Mon, Oct 26, 2020 at 04:32:34PM -0700, Darrick J. Wong wrote:
> From: Darrick J. Wong <darrick.wong@oracle.com>
> 
> Add a command to xfs_db so that we can navigate to inodes by path.
> 
> Signed-off-by: Darrick J. Wong <darrick.wong@oracle.com>
....
> +/* Given a directory and a structured path, walk the path and set the cursor. */
> +static int
> +path_navigate(
> +	struct xfs_mount	*mp,
> +	xfs_ino_t		rootino,
> +	struct dirpath		*dirpath)
> +{
> +	struct xfs_inode	*dp;
> +	xfs_ino_t		ino = rootino;
> +	unsigned int		i;
> +	int			error;
> +
> +	error = -libxfs_iget(mp, NULL, ino, 0, &dp);
> +	if (error)
> +		return error;
> +
> +	for (i = 0; i < dirpath->depth; i++) {
> +		struct xfs_name	xname = {
> +			.name	= dirpath->path[i],
> +			.len	= strlen(dirpath->path[i]),
> +		};
> +
> +		if (!S_ISDIR(VFS_I(dp)->i_mode)) {
> +			error = ENOTDIR;
> +			goto rele;
> +		}
> +
> +		error = -libxfs_dir_lookup(NULL, dp, &xname, &ino, NULL);
> +		if (error)
> +			goto rele;
> +		if (!xfs_verify_ino(mp, ino)) {
> +			error = EFSCORRUPTED;
> +			goto rele;
> +		}
> +
> +		libxfs_irele(dp);
> +		dp = NULL;
> +
> +		error = -libxfs_iget(mp, NULL, ino, 0, &dp);
> +		switch (error) {
> +		case EFSCORRUPTED:
> +		case EFSBADCRC:
> +		case 0:
> +			break;
> +		default:
> +			return error;
> +		}
> +	}
> +
> +	set_cur_inode(ino);
> +rele:
> +	if (dp)
> +		libxfs_irele(dp);
> +	return error;
> +}

This could return negative errors....

> +/* Walk a directory path to an inode and set the io cursor to that inode. */
> +static int
> +path_walk(
> +	char		*path)
> +{
> +	struct dirpath	*dirpath;
> +	char		*p = path;
> +	xfs_ino_t	rootino = mp->m_sb.sb_rootino;
> +	int		ret = 0;
> +
> +	if (*p == '/') {
> +		/* Absolute path, start from the root inode. */
> +		p++;
> +	} else {
> +		/* Relative path, start from current dir. */
> +		if (iocur_top->typ != &typtab[TYP_INODE]) {
> +			dbprintf(_("current object is not an inode.\n"));
> +			return -1;
> +		}
> +
> +		if (!S_ISDIR(iocur_top->mode)) {
> +			dbprintf(_("current inode %llu is not a directory.\n"),
> +					(unsigned long long)iocur_top->ino);
> +			return -1;
> +		}
> +		rootino = iocur_top->ino;
> +	}
> +
> +	dirpath = path_parse(p);
> +	if (!dirpath) {
> +		dbprintf(_("%s: not enough memory to parse.\n"), path);
> +		return -1;
> +	}

and this could return -ENOMEM here with no error message....

> +
> +	ret = path_navigate(mp, rootino, dirpath);
> +	if (ret) {
> +		dbprintf(_("%s: %s\n"), path, strerror(ret));
> +		ret = -1;
> +	}

... don't overwrite ret here, move the dbprintf() to the caller and
the one error message captures all possible errors.

Also, no need for _() for a format string that contains no
translatable text....

Otherwise, looks fine.

-Dave.
-- 
Dave Chinner
david@fromorbit.com

Re: [PATCH 1/2] xfs_db: add a directory path lookup command

[Darrick J. Wong]

On Wed, Oct 28, 2020 at 11:35:51AM +1100, Dave Chinner wrote:
> On Mon, Oct 26, 2020 at 04:32:34PM -0700, Darrick J. Wong wrote:
> > From: Darrick J. Wong <darrick.wong@oracle.com>
> > 
> > Add a command to xfs_db so that we can navigate to inodes by path.
> > 
> > Signed-off-by: Darrick J. Wong <darrick.wong@oracle.com>
> ....
> > +/* Given a directory and a structured path, walk the path and set the cursor. */
> > +static int
> > +path_navigate(
> > +	struct xfs_mount	*mp,
> > +	xfs_ino_t		rootino,
> > +	struct dirpath		*dirpath)
> > +{
> > +	struct xfs_inode	*dp;
> > +	xfs_ino_t		ino = rootino;
> > +	unsigned int		i;
> > +	int			error;
> > +
> > +	error = -libxfs_iget(mp, NULL, ino, 0, &dp);
> > +	if (error)
> > +		return error;
> > +
> > +	for (i = 0; i < dirpath->depth; i++) {
> > +		struct xfs_name	xname = {
> > +			.name	= dirpath->path[i],
> > +			.len	= strlen(dirpath->path[i]),
> > +		};
> > +
> > +		if (!S_ISDIR(VFS_I(dp)->i_mode)) {
> > +			error = ENOTDIR;
> > +			goto rele;
> > +		}
> > +
> > +		error = -libxfs_dir_lookup(NULL, dp, &xname, &ino, NULL);
> > +		if (error)
> > +			goto rele;
> > +		if (!xfs_verify_ino(mp, ino)) {
> > +			error = EFSCORRUPTED;
> > +			goto rele;
> > +		}
> > +
> > +		libxfs_irele(dp);
> > +		dp = NULL;
> > +
> > +		error = -libxfs_iget(mp, NULL, ino, 0, &dp);
> > +		switch (error) {
> > +		case EFSCORRUPTED:
> > +		case EFSBADCRC:
> > +		case 0:
> > +			break;
> > +		default:
> > +			return error;
> > +		}
> > +	}
> > +
> > +	set_cur_inode(ino);
> > +rele:
> > +	if (dp)
> > +		libxfs_irele(dp);
> > +	return error;
> > +}
> 
> This could return negative errors....
> 
> > +/* Walk a directory path to an inode and set the io cursor to that inode. */
> > +static int
> > +path_walk(
> > +	char		*path)
> > +{
> > +	struct dirpath	*dirpath;
> > +	char		*p = path;
> > +	xfs_ino_t	rootino = mp->m_sb.sb_rootino;
> > +	int		ret = 0;
> > +
> > +	if (*p == '/') {
> > +		/* Absolute path, start from the root inode. */
> > +		p++;
> > +	} else {
> > +		/* Relative path, start from current dir. */
> > +		if (iocur_top->typ != &typtab[TYP_INODE]) {
> > +			dbprintf(_("current object is not an inode.\n"));
> > +			return -1;
> > +		}
> > +
> > +		if (!S_ISDIR(iocur_top->mode)) {
> > +			dbprintf(_("current inode %llu is not a directory.\n"),
> > +					(unsigned long long)iocur_top->ino);
> > +			return -1;
> > +		}
> > +		rootino = iocur_top->ino;
> > +	}
> > +
> > +	dirpath = path_parse(p);
> > +	if (!dirpath) {
> > +		dbprintf(_("%s: not enough memory to parse.\n"), path);
> > +		return -1;
> > +	}
> 
> and this could return -ENOMEM here with no error message....
> 
> > +
> > +	ret = path_navigate(mp, rootino, dirpath);
> > +	if (ret) {
> > +		dbprintf(_("%s: %s\n"), path, strerror(ret));
> > +		ret = -1;
> > +	}
> 
> ... don't overwrite ret here, move the dbprintf() to the caller and
> the one error message captures all possible errors.
> 
> Also, no need for _() for a format string that contains no
> translatable text....

Ok, will fix.  Thanks!

--D

> Otherwise, looks fine.
> 
> -Dave.
> -- 
> Dave Chinner
> david@fromorbit.com

Re: [PATCH 1/2] xfs_db: add a directory path lookup command

[Eric Sandeen]

On 10/26/20 6:32 PM, Darrick J. Wong wrote:
> From: Darrick J. Wong <darrick.wong@oracle.com>
> 
> Add a command to xfs_db so that we can navigate to inodes by path.
> 
> Signed-off-by: Darrick J. Wong <darrick.wong@oracle.com>

...


> +/* Path lookup */
> +
> +/* Key for looking up metadata inodes. */
> +struct dirpath {
> +	/* Array of string pointers. */
> +	char		**path;
> +
> +	/* Number of strings in path. */
> +	unsigned int	depth;
> +};

This generates warnings for me in gcc-4.8.5 (hah, I know) as well as
gcc-9.

namei.c:101:12: warning: pointer targets in initialization of ‘const unsigned char *’ from ‘char *’ differ in signedness [-Wpointer-sign]

due to the "unsigned char *" type from:

commit e2bcd936eb95d0019ca5e05f9fdd27e770ddded1
Author: Dave Chinner <david@fromorbit.com>
Date:   Wed Jan 20 10:44:58 2010 +1100

    xfs: directory names are unsigned
    
    Convert the struct xfs_name to use unsigned chars for the name
    strings to match both what is stored on disk (__uint8_t) and what
    the VFS expects (unsigned char).
    
    Signed-off-by: Dave Chinner <david@fromorbit.com>
    Reviewed-by: Christoph Hellwig <hch@lst.de>

so maybe just cast to shut it up?
diff --git a/db/namei.c b/db/namei.c
index 4b467ff8..a902f302 100644
--- a/db/namei.c
+++ b/db/namei.c
@@ -98,7 +98,7 @@ path_navigate(
 
 	for (i = 0; i < dirpath->depth; i++) {
 		struct xfs_name	xname = {
-			.name	= dirpath->path[i],
+			.name	= (unsigned char *)dirpath->path[i],
 			.len	= strlen(dirpath->path[i]),
 		};
 
@@ -253,7 +253,7 @@ dir_emit(
 	uint8_t			dtype)
 {
 	char			*display_name;
-	struct xfs_name		xname = { .name = name };
+	struct xfs_name		xname = { .name = (unsigned char *)name };
 	const char		*dstr = get_dstr(mp, dtype);
 	xfs_dahash_t		hash;
 	bool			good;