[03/10] xfs_io: support the new getfsmap ioctl

Commit Message

Darrick J. Wong June 2, 2017, 7:51 p.m. UTC

From: Darrick J. Wong <[e-mail]>

Signed-off-by: Darrick J. Wong <[e-mail]>
---
 io/Makefile          |    7 +
 io/copy_file_range.c |    2 
 io/encrypt.c         |    1 
 io/fsmap.c           |  549 ++++++++++++++++++++++++++++++++++++++++++++++++++
 io/init.c            |    8 +
 io/io.h              |   14 +
 io/open.c            |   21 ++
 io/pwrite.c          |    2 
 io/reflink.c         |    4 
 io/sendfile.c        |    2 
 man/man8/xfs_io.8    |   66 ++++++
 11 files changed, 663 insertions(+), 13 deletions(-)
 create mode 100644 io/fsmap.c



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Comments

Eric Sandeen June 13, 2017, 10:20 p.m. UTC | #1

On 6/2/17 2:51 PM, Darrick J. Wong wrote:
> From: Darrick J. Wong <[e-mail]>
> 
> Signed-off-by: Darrick J. Wong <[e-mail]>

Sorry Darrick, lots more here that I missed the first time around.

> ---
>  io/Makefile          |    7 +
>  io/copy_file_range.c |    2 
>  io/encrypt.c         |    1 
>  io/fsmap.c           |  549 ++++++++++++++++++++++++++++++++++++++++++++++++++
>  io/init.c            |    8 +
>  io/io.h              |   14 +
>  io/open.c            |   21 ++
>  io/pwrite.c          |    2 
>  io/reflink.c         |    4 
>  io/sendfile.c        |    2 
>  man/man8/xfs_io.8    |   66 ++++++
>  11 files changed, 663 insertions(+), 13 deletions(-)
>  create mode 100644 io/fsmap.c
> 
> 
> diff --git a/io/Makefile b/io/Makefile
> index 435ccff..47b0a66 100644
> --- a/io/Makefile
> +++ b/io/Makefile
> @@ -99,6 +99,13 @@ ifeq ($(HAVE_MREMAP),yes)
>  LCFLAGS += -DHAVE_MREMAP
>  endif
>  
> +# On linux we get fsmap from the system or define it ourselves
> +# so include this based on platform type.  If this reverts to only
> +# the autoconf check w/o local definition, change to testing HAVE_GETFSMAP
> +ifeq ($(PKG_PLATFORM),linux)
> +CFILES += fsmap.c
> +endif
> +
>  default: depend $(LTCOMMAND)
>  
>  include $(BUILDRULES)
> diff --git a/io/copy_file_range.c b/io/copy_file_range.c
> index 249c649..d1dfc5a 100644
> --- a/io/copy_file_range.c
> +++ b/io/copy_file_range.c
> @@ -121,7 +121,7 @@ copy_range_f(int argc, char **argv)
>  	if (optind != argc - 1)
>  		return command_usage(&copy_range_cmd);
>  
> -	fd = openfile(argv[optind], NULL, IO_READONLY, 0);
> +	fd = openfile(argv[optind], NULL, IO_READONLY, 0, NULL);
>  	if (fd < 0)
>  		return 0;
>  
> diff --git a/io/encrypt.c b/io/encrypt.c
> index d844c5e..26ab97c 100644
> --- a/io/encrypt.c
> +++ b/io/encrypt.c
> @@ -20,6 +20,7 @@
>  #include "platform_defs.h"
>  #include "command.h"
>  #include "init.h"
> +#include "path.h"
>  #include "io.h"
>  
>  #ifndef ARRAY_SIZE
> diff --git a/io/fsmap.c b/io/fsmap.c
> new file mode 100644
> index 0000000..1f4de81
> --- /dev/null
> +++ b/io/fsmap.c
> @@ -0,0 +1,549 @@
> +/*
> + * Copyright (C) 2017 Oracle.  All Rights Reserved.
> + *
> + * Author: Darrick J. Wong <[e-mail]>
> + *
> + * This program is free software; you can redistribute it and/or
> + * modify it under the terms of the GNU General Public License
> + * as published by the Free Software Foundation; either version 2
> + * of the License, or (at your option) any later version.
> + *
> + * This program is distributed in the hope that it would be useful,
> + * but WITHOUT ANY WARRANTY; without even the implied warranty of
> + * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
> + * GNU General Public License for more details.
> + *
> + * You should have received a copy of the GNU General Public License
> + * along with this program; if not, write the Free Software Foundation,
> + * Inc.,  51 Franklin St, Fifth Floor, Boston, MA  02110-1301, USA.
> + */
> +#include "platform_defs.h"
> +#include "command.h"
> +#include "init.h"
> +#include "path.h"
> +#include "io.h"
> +#include "input.h"
> +
> +static cmdinfo_t	fsmap_cmd;
> +static dev_t		xfs_data_dev;
> +
> +static void
> +fsmap_help(void)
> +{
> +	printf(_(
> +"\n"
> +" Prints the block mapping for a filesystem"
> +"\n"
> +" Example:\n"
> +" 'fsmap [-d|-l|-r] [-v] [-n nr] [startoff] [endoff]' - tabular format verbose map, including unwritten extents\n"

Whoops, I missed this the first time, that's a restatement of all options,
not an example.

(Or I'd probably just drop it, I don't think an example is needed
or useful, but as you like it... I guess it's modeled on fiemap)

> +"\n"
> +" fsmap prints the map of disk blocks used by the whole filesystem.\n"
> +" When possible, owner and offset information will be included in the\n"
> +" sapce report.\n"
> +"\n"
> +" By default, each line of the listing takes the following form:\n"
> +"     extent: [startoffset..endoffset] owner startblock..endblock\n"

Hm, no:

	0: 8:17 [0..1175]: unknown 1176 blocks
	1: 8:17 [1176..1183]: free space 8 blocks

manpage gets it right:

extent: major:minor [startblock..endblock]: owner startoffset..endoffset length

(I might drop the last "blocks"... is it useful?  fiemap doesn't use it)


Sigh, sorry for missing stuff on the first round.

OK fiemap prints a header with -v ...

# io/xfs_io -c "fiemap -v" /mnt/test/junk
/mnt/test/junk:
 EXT: FILE-OFFSET      BLOCK-RANGE      TOTAL FLAGS
   0: [0..7]:          hole                 8
   1: [8..39]:         5936..5967          32   0x0

I think that'd be useful here, too ... oh, bug.  see below.  (s/nr == 0/*nr == 0/)

> +" The owner field is either an inode number or a special value.\n"
> +" All the file offsets and disk blocks are in units of 512-byte blocks.\n"
> +" -d -- query only the data device.\n"

(this is the default, yes?)

> +" -l -- query only the log device.\n"

Hm, with an external log I get:

xfs_io> fsmap -l
	0: 7:7 [0..2097151]: journalling log 2097152 blocks

but an internal log does not show those blocks in the output, should it?

> +" -r -- query only the realtime device.\n"
> +" -n -- query n extents.\n"

-n doesn't seem to work as described:

# io/xfs_io -c "fsmap -n 2" /mnt/test
	0: 8:17 [0..1175]: unknown 1176 blocks
	1: 8:17 [1176..1183]: free space 8 blocks
	2: 8:17 [1184..1327]: unknown 144 blocks
	3: 8:17 [1328..1343]: free space 16 blocks

Oh, it's "at a time" - so help text needs to be fixed to reflect that it's 
the size of each query, not the total number queried.

> +" -v -- Verbose information, specify ag info.  Show flags legend on 2nd -v\n"

(and FILE-OFFSET of each owner?)

There are no flags printed AFAICT, and no different behavior with -vv...
but that seems broken somewhere.

Oh, it looks like if no flags are (will be?) printed we skip the column
and the legend.  That seems a little odd to me... is it intentional?

> +"\n"));
> +}
> +
> +#define OWNER_BUF_SZ	32
> +static const char *
> +special_owner(
> +	int64_t		owner,
> +	char		*buf)
> +{
> +	switch (owner) {
> +	case XFS_FMR_OWN_FREE:
> +		return _("free space");

(Aside: I wonder if there's any way to avoid spaces in the owner field,
so that awk can easily parse the result...?  Not sure how that'd look,
but it'd make it a lot more useful when presented with thousands of
records)

> +	case XFS_FMR_OWN_UNKNOWN:
> +		return _("unknown");
> +	case XFS_FMR_OWN_FS:
> +		return _("static fs metadata");
> +	case XFS_FMR_OWN_LOG:
> +		return _("journalling log");
> +	case XFS_FMR_OWN_AG:
> +		return _("per-AG metadata");
> +	case XFS_FMR_OWN_INOBT:
> +		return _("inode btree");
> +	case XFS_FMR_OWN_INODES:
> +		return _("inodes");
> +	case XFS_FMR_OWN_REFC:
> +		return _("refcount btree");
> +	case XFS_FMR_OWN_COW:
> +		return _("cow reservation");
> +	case XFS_FMR_OWN_DEFECTIVE:
> +		return _("defective");
> +	default:
> +		snprintf(buf, OWNER_BUF_SZ, _("special %u:%u"),
> +				FMR_OWNER_TYPE(owner), FMR_OWNER_CODE(owner));
> +		return buf;
> +	}
> +}
> +
> +static void
> +dump_map(
> +	unsigned long long	*nr,
> +	struct fsmap_head	*head)
> +{
> +	unsigned long long	i;
> +	struct fsmap		*p;
> +	char			owner[OWNER_BUF_SZ];
> +
> +	for (i = 0, p = head->fmh_recs; i < head->fmh_entries; i++, p++) {
> +		printf("\t%llu: %u:%u [%lld..%lld]: ", i + (*nr),
> +			major(p->fmr_device), minor(p->fmr_device),
> +			(long long)BTOBBT(p->fmr_physical),
> +			(long long)BTOBBT(p->fmr_physical + p->fmr_length - 1));
> +		if (p->fmr_flags & FMR_OF_SPECIAL_OWNER)
> +			printf("%s", special_owner(p->fmr_owner, owner));
> +		else if (p->fmr_flags & FMR_OF_EXTENT_MAP)
> +			printf(_("inode %lld extent map"),
> +				(long long) p->fmr_owner);
> +		else
> +			printf(_("inode %lld %lld..%lld"),
> +				(long long)p->fmr_owner,
> +				(long long)BTOBBT(p->fmr_offset),
> +				(long long)BTOBBT(p->fmr_offset + p->fmr_length - 1));
> +		printf(_(" %lld blocks\n"),
> +			(long long)BTOBBT(p->fmr_length));
> +	}
> +
> +	(*nr) += head->fmh_entries;
> +}
> +
> +/*
> + * Verbose mode displays:
> + *   extent: major:minor [startblock..endblock]: startoffset..endoffset \
> + *	ag# (agoffset..agendoffset) totalbbs flags
> + */
> +#define MINRANGE_WIDTH	16
> +#define MINAG_WIDTH	2
> +#define MINTOT_WIDTH	5
> +#define NFLG		7		/* count of flags */
> +#define	FLG_NULL	00000000	/* Null flag */
> +#define	FLG_ATTR_FORK	01000000	/* attribute fork */
> +#define	FLG_SHARED	00100000	/* shared extent */
> +#define	FLG_PRE		00010000	/* Unwritten extent */
> +#define	FLG_BSU		00001000	/* Not on begin of stripe unit  */
> +#define	FLG_ESU		00000100	/* Not on end   of stripe unit  */
> +#define	FLG_BSW		00000010	/* Not on begin of stripe width */
> +#define	FLG_ESW		00000001	/* Not on end   of stripe width */
> +static void
> +dump_map_verbose(
> +	unsigned long long	*nr,
> +	struct fsmap_head	*head,
> +	bool			*dumped_flags,
> +	struct xfs_fsop_geom	*fsgeo)
> +{
> +	unsigned long long	i;
> +	struct fsmap		*p;
> +	int			agno;
> +	off64_t			agoff, bperag;
> +	int			foff_w, boff_w, aoff_w, tot_w, agno_w, own_w;
> +	int			nr_w, dev_w;
> +	char			rbuf[32], bbuf[32], abuf[32], obuf[32];
> +	char			nbuf[32], dbuf[32], gbuf[32];
> +	char			owner[OWNER_BUF_SZ];
> +	int			sunit, swidth;
> +	int			flg = 0;
> +
> +	foff_w = boff_w = aoff_w = own_w = MINRANGE_WIDTH;
> +	dev_w = 3;
> +	nr_w = 4;
> +	tot_w = MINTOT_WIDTH;
> +	bperag = (off64_t)fsgeo->agblocks *
> +		  (off64_t)fsgeo->blocksize;
> +	sunit = (fsgeo->sunit * fsgeo->blocksize);
> +	swidth = (fsgeo->swidth * fsgeo->blocksize);
> +
> +	/*
> +	 * Go through the extents and figure out the width
> +	 * needed for all columns.
> +	 */
> +	for (i = 0, p = head->fmh_recs; i < head->fmh_entries; i++, p++) {
> +		if (p->fmr_flags & FMR_OF_PREALLOC ||
> +		    p->fmr_flags & FMR_OF_ATTR_FORK ||
> +		    p->fmr_flags & FMR_OF_SHARED)
> +			flg = 1;
> +		if (sunit &&
> +		    (p->fmr_physical  % sunit != 0 ||
> +		     ((p->fmr_physical + p->fmr_length) % sunit) != 0 ||
> +		     p->fmr_physical % swidth != 0 ||
> +		     ((p->fmr_physical + p->fmr_length) % swidth) != 0))
> +			flg = 1;
> +		if (flg)
> +			*dumped_flags = true;
> +		snprintf(nbuf, sizeof(nbuf), "%llu", (*nr) + i);
> +		nr_w = max(nr_w, strlen(nbuf));
> +		if (head->fmh_oflags & FMH_OF_DEV_T)
> +			snprintf(dbuf, sizeof(dbuf), "%u:%u",
> +				major(p->fmr_device),
> +				minor(p->fmr_device));
> +		else
> +			snprintf(dbuf, sizeof(dbuf), "0x%x", p->fmr_device);
> +		dev_w = max(dev_w, strlen(dbuf));
> +		snprintf(bbuf, sizeof(bbuf), "[%lld..%lld]:",
> +			(long long)BTOBBT(p->fmr_physical),
> +			(long long)BTOBBT(p->fmr_physical + p->fmr_length - 1));
> +		boff_w = max(boff_w, strlen(bbuf));
> +		if (p->fmr_flags & FMR_OF_SPECIAL_OWNER)
> +			own_w = max(own_w, strlen(
> +					special_owner(p->fmr_owner, owner)));
> +		else {
> +			snprintf(obuf, sizeof(obuf), "%lld",
> +				(long long)p->fmr_owner);
> +			own_w = max(own_w, strlen(obuf));
> +		}
> +		if (p->fmr_flags & FMR_OF_EXTENT_MAP)
> +			foff_w = max(foff_w, strlen(_("extent_map")));
> +		else if (p->fmr_flags & FMR_OF_SPECIAL_OWNER)
> +			;
> +		else {
> +			snprintf(rbuf, sizeof(rbuf), "%lld..%lld",
> +				(long long)BTOBBT(p->fmr_offset),
> +				(long long)BTOBBT(p->fmr_offset + p->fmr_length - 1));
> +			foff_w = max(foff_w, strlen(rbuf));
> +		}
> +		if (p->fmr_device == xfs_data_dev) {
> +			agno = p->fmr_physical / bperag;
> +			agoff = p->fmr_physical - (agno * bperag);
> +			snprintf(abuf, sizeof(abuf),
> +				"(%lld..%lld)",
> +				(long long)BTOBBT(agoff),
> +				(long long)BTOBBT(agoff + p->fmr_length - 1));
> +		} else
> +			abuf[0] = 0;
> +		aoff_w = max(aoff_w, strlen(abuf));
> +		tot_w = max(tot_w,
> +			numlen(BTOBBT(p->fmr_length), 10));
> +	}
> +	agno_w = max(MINAG_WIDTH, numlen(fsgeo->agcount, 10));
> +	if (nr == 0)

if (*nr == 0)

> +		printf("%*s: %-*s %-*s %-*s %-*s %*s %-*s %*s%s\n",
> +			nr_w, _("EXT"),
> +			dev_w, _("DEV"),
> +			boff_w, _("BLOCK-RANGE"),
> +			own_w, _("OWNER"),
> +			foff_w, _("FILE-OFFSET"),
> +			agno_w, _("AG"),
> +			aoff_w, _("AG-OFFSET"),
> +			tot_w, _("TOTAL"),
> +			flg ? _(" FLAGS") : "");
> +	for (i = 0, p = head->fmh_recs; i < head->fmh_entries; i++, p++) {
> +		flg = FLG_NULL;
> +		if (p->fmr_flags & FMR_OF_PREALLOC)
> +			flg |= FLG_PRE;
> +		if (p->fmr_flags & FMR_OF_ATTR_FORK)
> +			flg |= FLG_ATTR_FORK;
> +		if (p->fmr_flags & FMR_OF_SHARED)
> +			flg |= FLG_SHARED;
> +		/*
> +		 * If striping enabled, determine if extent starts/ends
> +		 * on a stripe unit boundary.
> +		 */
> +		if (sunit) {
> +			if (p->fmr_physical  % sunit != 0)
> +				flg |= FLG_BSU;
> +			if (((p->fmr_physical +
> +			      p->fmr_length ) % sunit ) != 0)
> +				flg |= FLG_ESU;
> +			if (p->fmr_physical % swidth != 0)
> +				flg |= FLG_BSW;
> +			if (((p->fmr_physical +
> +			      p->fmr_length ) % swidth ) != 0)
> +				flg |= FLG_ESW;
> +		}
> +		if (head->fmh_oflags & FMH_OF_DEV_T)
> +			snprintf(dbuf, sizeof(dbuf), "%u:%u",
> +				major(p->fmr_device),
> +				minor(p->fmr_device));
> +		else
> +			snprintf(dbuf, sizeof(dbuf), "0x%x", p->fmr_device);
> +		snprintf(bbuf, sizeof(bbuf), "[%lld..%lld]:",
> +			(long long)BTOBBT(p->fmr_physical),
> +			(long long)BTOBBT(p->fmr_physical + p->fmr_length - 1));
> +		if (p->fmr_flags & FMR_OF_SPECIAL_OWNER) {
> +			snprintf(obuf, sizeof(obuf), "%s",
> +				special_owner(p->fmr_owner, owner));
> +			snprintf(rbuf, sizeof(rbuf), " ");
> +		} else {
> +			snprintf(obuf, sizeof(obuf), "%lld",
> +				(long long)p->fmr_owner);
> +			snprintf(rbuf, sizeof(rbuf), "%lld..%lld",
> +				(long long)BTOBBT(p->fmr_offset),
> +				(long long)BTOBBT(p->fmr_offset + p->fmr_length - 1));
> +		}
> +		if (p->fmr_device == xfs_data_dev) {
> +			agno = p->fmr_physical / bperag;
> +			agoff = p->fmr_physical - (agno * bperag);
> +			snprintf(abuf, sizeof(abuf),
> +				"(%lld..%lld)",
> +				(long long)BTOBBT(agoff),
> +				(long long)BTOBBT(agoff + p->fmr_length - 1));
> +			snprintf(gbuf, sizeof(gbuf),
> +				"%lld",
> +				(long long)agno);
> +		} else {
> +			abuf[0] = 0;
> +			gbuf[0] = 0;
> +		}
> +		if (p->fmr_flags & FMR_OF_EXTENT_MAP)
> +			printf("%*llu: %-*s %-*s %-*s %-*s %-*s %-*s %*lld\n",
> +				nr_w, (*nr) + i,
> +				dev_w, dbuf,
> +				boff_w, bbuf,
> +				own_w, obuf,
> +				foff_w, _("extent map"),
> +				agno_w, gbuf,
> +				aoff_w, abuf,
> +				tot_w, (long long)BTOBBT(p->fmr_length));
> +		else {
> +			printf("%*llu: %-*s %-*s %-*s %-*s", nr_w, (*nr) + i,
> +				dev_w, dbuf, boff_w, bbuf, own_w, obuf,
> +				foff_w, rbuf);
> +			printf(" %-*s %-*s", agno_w, gbuf,
> +				aoff_w, abuf);
> +			printf(" %*lld", tot_w,
> +				(long long)BTOBBT(p->fmr_length));
> +			if (flg == FLG_NULL)
> +				printf("\n");
> +			else
> +				printf(" %-*.*o\n", NFLG, NFLG, flg);
> +		}
> +	}
> +
> +	(*nr) += head->fmh_entries;
> +}
> +
> +static void
> +dump_verbose_key(void)
> +{
> +	printf(_(" FLAG Values:\n"));
> +	printf(_("    %*.*o Attribute fork\n"),
> +		NFLG+1, NFLG+1, FLG_ATTR_FORK);
> +	printf(_("    %*.*o Shared extent\n"),
> +		NFLG+1, NFLG+1, FLG_SHARED);
> +	printf(_("    %*.*o Unwritten preallocated extent\n"),
> +		NFLG+1, NFLG+1, FLG_PRE);
> +	printf(_("    %*.*o Doesn't begin on stripe unit\n"),
> +		NFLG+1, NFLG+1, FLG_BSU);
> +	printf(_("    %*.*o Doesn't end   on stripe unit\n"),
> +		NFLG+1, NFLG+1, FLG_ESU);
> +	printf(_("    %*.*o Doesn't begin on stripe width\n"),
> +		NFLG+1, NFLG+1, FLG_BSW);
> +	printf(_("    %*.*o Doesn't end   on stripe width\n"),
> +		NFLG+1, NFLG+1, FLG_ESW);
> +}
> +
> +int
> +fsmap_f(
> +	int			argc,
> +	char			**argv)
> +{
> +	struct fsmap		*p;
> +	struct fsmap_head	*nhead;
> +	struct fsmap_head	*head;
> +	struct fsmap		*l, *h;
> +	struct xfs_fsop_geom	fsgeo;
> +	long long		start = 0;
> +	long long		end = -1;
> +	int			nmap_size;
> +	int			map_size;
> +	int			nflag = 0;
> +	int			vflag = 0;
> +	int			i = 0;
> +	int			c;
> +	unsigned long long	nr = 0;
> +	size_t			fsblocksize, fssectsize;
> +	struct fs_path		*fs;
> +	static bool		tab_init;
> +	bool			dumped_flags = false;
> +	int			dflag, lflag, rflag;
> +
> +	init_cvtnum(&fsblocksize, &fssectsize);
> +
> +	dflag = lflag = rflag = 0;
> +	while ((c = getopt(argc, argv, "dln:rv")) != EOF) {
> +		switch (c) {
> +		case 'd':	/* data device */
> +			dflag = 1;
> +			break;
> +		case 'l':	/* log device */
> +			lflag = 1;
> +			break;
> +		case 'n':	/* number of extents specified */
> +			nflag = atoi(optarg);
> +			break;
> +		case 'r':	/* rt device */
> +			rflag = 1;
> +			break;
> +		case 'v':	/* Verbose output */
> +			vflag++;
> +			break;
> +		default:
> +			return command_usage(&fsmap_cmd);
> +		}
> +	}
> +
> +	if (dflag + lflag + rflag > 1)
> +		return command_usage(&fsmap_cmd);
> +
> +	if (argc > optind && dflag + lflag + rflag == 0)
> +		return command_usage(&fsmap_cmd);
> +
> +	if (argc > optind) {
> +		start = cvtnum(fsblocksize, fssectsize, argv[optind]);
> +		if (start < 0) {
> +			fprintf(stderr,
> +				_("Bad rmap start_bblock %s.\n"),
> +				argv[optind]);
> +			return 0;
> +		}
> +		start <<= BBSHIFT;
> +	}
> +
> +	if (argc > optind + 1) {
> +		end = cvtnum(fsblocksize, fssectsize, argv[optind + 1]);
> +		if (end < 0) {
> +			fprintf(stderr,
> +				_("Bad rmap end_bblock %s.\n"),
> +				argv[optind + 1]);
> +			return 0;
> +		}
> +		end <<= BBSHIFT;
> +	}
> +
> +	if (vflag) {
> +		c = ioctl(file->fd, XFS_IOC_FSGEOMETRY, &fsgeo);
> +		if (c < 0) {
> +			fprintf(stderr,
> +				_("%s: can't get geometry [\"%s\"]: %s\n"),
> +				progname, file->name, strerror(errno));
> +			exitcode = 1;
> +			return 0;
> +		}
> +	}
> +
> +	map_size = nflag ? nflag : 131072 / sizeof(struct fsmap);

Manpage, below:

"In the absence of -n, xfs_fsmap queries the system for the number of extents in the filesystem
and uses that value to compute the group size."

Looks hard-coded to 131072, no?

> +	head = malloc(fsmap_sizeof(map_size));
> +	if (head == NULL) {
> +		fprintf(stderr, _("%s: malloc of %zu bytes failed.\n"),
> +			progname, fsmap_sizeof(map_size));
> +		exitcode = 1;
> +		return 0;
> +	}
> +
> +	memset(head, 0, sizeof(*head));
> +	l = head->fmh_keys;
> +	h = head->fmh_keys + 1;
> +	if (dflag) {
> +		l->fmr_device = h->fmr_device = file->fs_path.fs_datadev;
> +	} else if (lflag) {
> +		l->fmr_device = h->fmr_device = file->fs_path.fs_logdev;
> +	} else if (rflag) {
> +		l->fmr_device = h->fmr_device = file->fs_path.fs_rtdev;
> +	} else {
> +		l->fmr_device = 0;
> +		h->fmr_device = UINT_MAX;
> +	}
> +	l->fmr_physical = start;
> +	h->fmr_physical = end;
> +	h->fmr_owner = ULLONG_MAX;
> +	h->fmr_flags = UINT_MAX;
> +	h->fmr_offset = ULLONG_MAX;
> +
> +	/* Count mappings */
> +	if (!nflag) {
> +		head->fmh_count = 0;
> +		i = ioctl(file->fd, FS_IOC_GETFSMAP, head);
> +		if (i < 0) {
> +			fprintf(stderr, _("%s: xfsctl(XFS_IOC_GETFSMAP)"
> +				" iflags=0x%x [\"%s\"]: %s\n"),
> +				progname, head->fmh_iflags, file->name,
> +				strerror(errno));
> +			free(head);
> +			exitcode = 1;
> +			return 0;
> +		}
> +		if (head->fmh_entries > map_size + 2) {
> +			map_size = 11ULL * head->fmh_entries / 10;
> +			nmap_size = map_size > (1 << 24) ? (1 << 24) : map_size;
> +			nhead = realloc(head, fsmap_sizeof(nmap_size));
> +			if (nhead == NULL) {
> +				fprintf(stderr,
> +					_("%s: cannot realloc %zu bytes\n"),
> +					progname, fsmap_sizeof(nmap_size));
> +			} else {
> +				head = nhead;
> +				map_size = nmap_size;
> +			}
> +		}
> +	}
> +
> +	/*
> +	 * If this is an XFS filesystem, remember the data device.
> +	 * (We report AG number/block for data device extents on XFS).
> +	 */
> +	if (!tab_init) {
> +		fs_table_initialise(0, NULL, 0, NULL);
> +		tab_init = true;
> +	}
> +	fs = fs_table_lookup(file->name, FS_MOUNT_POINT);
> +	xfs_data_dev = fs ? fs->fs_datadev : 0;
> +
> +	head->fmh_count = map_size;
> +	do {
> +		/* Get some extents */
> +		i = ioctl(file->fd, FS_IOC_GETFSMAP, head);
> +		if (i < 0) {
> +			fprintf(stderr, _("%s: xfsctl(XFS_IOC_GETFSMAP)"
> +				" iflags=0x%x [\"%s\"]: %s\n"),
> +				progname, head->fmh_iflags, file->name,
> +				strerror(errno));
> +			free(head);
> +			exitcode = 1;
> +			return 0;
> +		}
> +
> +		if (head->fmh_entries == 0)
> +			break;
> +
> +		if (!vflag)
> +			dump_map(&nr, head);
> +		else
> +			dump_map_verbose(&nr, head, &dumped_flags, &fsgeo);
> +
> +		p = &head->fmh_recs[head->fmh_entries - 1];
> +		if (p->fmr_flags & FMR_OF_LAST)
> +			break;
> +		fsmap_advance(head);
> +	} while (true);
> +
> +	if (dumped_flags)
> +		dump_verbose_key();
> +
> +	free(head);
> +	return 0;
> +}
> +
> +void
> +fsmap_init(void)
> +{
> +	fsmap_cmd.name = "fsmap";
> +	fsmap_cmd.cfunc = fsmap_f;
> +	fsmap_cmd.argmin = 0;
> +	fsmap_cmd.argmax = -1;
> +	fsmap_cmd.flags = CMD_NOMAP_OK | CMD_FLAG_FOREIGN_OK;
> +	fsmap_cmd.args = _("[-d|-l|-r] [-v] [-n nx] [start] [end]");
> +	fsmap_cmd.oneline = _("print filesystem mapping for a range of blocks");
> +	fsmap_cmd.help = fsmap_help;
> +
> +	add_command(&fsmap_cmd);
> +}
> diff --git a/io/init.c b/io/init.c
> index c15a1e1..20d5f80 100644
> --- a/io/init.c
> +++ b/io/init.c
> @@ -66,6 +66,7 @@ init_commands(void)
>  	file_init();
>  	flink_init();
>  	freeze_init();
> +	fsmap_init();
>  	fsync_init();
>  	getrusage_init();
>  	help_init();
> @@ -139,6 +140,7 @@ init(
>  	char		*sp;
>  	mode_t		mode = 0600;
>  	xfs_fsop_geom_t	geometry = { 0 };
> +	struct fs_path	fsp;
>  
>  	progname = basename(argv[0]);
>  	setlocale(LC_ALL, "");
> @@ -148,6 +150,7 @@ init(
>  	pagesize = getpagesize();
>  	gettimeofday(&stopwatch, NULL);
>  
> +	fs_table_initialise(0, NULL, 0, NULL);
>  	while ((c = getopt(argc, argv, "ac:C:dFfim:p:nrRstTVx")) != EOF) {
>  		switch (c) {
>  		case 'a':
> @@ -212,11 +215,12 @@ init(
>  	}
>  
>  	while (optind < argc) {
> -		if ((c = openfile(argv[optind], &geometry, flags, mode)) < 0)
> +		c = openfile(argv[optind], &geometry, flags, mode, &fsp);
> +		if (c < 0)
>  			exit(1);
>  		if (!platform_test_xfs_fd(c))
>  			flags |= IO_FOREIGN;
> -		if (addfile(argv[optind], c, &geometry, flags) < 0)
> +		if (addfile(argv[optind], c, &geometry, flags, &fsp) < 0)
>  			exit(1);
>  		optind++;
>  	}
> diff --git a/io/io.h b/io/io.h
> index 952bdb8..6a0fe65 100644
> --- a/io/io.h
> +++ b/io/io.h
> @@ -17,6 +17,7 @@
>   */
>  
>  #include "xfs.h"
> +#include "path.h"
>  
>  /*
>   * Read/write patterns (default is always "forward")
> @@ -47,6 +48,7 @@ typedef struct fileio {
>  	int		flags;		/* flags describing file state */
>  	char		*name;		/* file name at time of open */
>  	xfs_fsop_geom_t	geom;		/* XFS filesystem geometry */
> +	struct fs_path	fs_path;	/* XFS path information */
>  } fileio_t;
>  
>  extern fileio_t		*filetable;	/* open file table */
> @@ -76,8 +78,10 @@ extern void *check_mapping_range(mmap_region_t *, off64_t, size_t, int);
>   */
>  
>  extern off64_t		filesize(void);
> -extern int		openfile(char *, xfs_fsop_geom_t *, int, mode_t);
> -extern int		addfile(char *, int , xfs_fsop_geom_t *, int);
> +extern int		openfile(char *, xfs_fsop_geom_t *, int, mode_t,
> +				 struct fs_path *);
> +extern int		addfile(char *, int , xfs_fsop_geom_t *, int,
> +				struct fs_path *);
>  extern void		printxattr(uint, int, int, const char *, int, int);
>  
>  extern unsigned int	recurse_all;
> @@ -174,3 +178,9 @@ extern void		readdir_init(void);
>  extern void		reflink_init(void);
>  
>  extern void		cowextsize_init(void);
> +
> +#ifdef HAVE_GETFSMAP
> +extern void		fsmap_init(void);
> +#else
> +# define fsmap_init()	do { } while (0)
> +#endif
> diff --git a/io/open.c b/io/open.c
> index 2ed55cf..b50f068 100644
> --- a/io/open.c
> +++ b/io/open.c
> @@ -52,8 +52,10 @@ openfile(
>  	char		*path,
>  	xfs_fsop_geom_t	*geom,
>  	int		flags,
> -	mode_t		mode)
> +	mode_t		mode,
> +	struct fs_path	*fs_path)
>  {
> +	struct fs_path	*fsp;
>  	int		fd;
>  	int		oflags;
>  
> @@ -118,6 +120,14 @@ openfile(
>  			}
>  		}
>  	}
> +
> +	if (fs_path) {
> +		fsp = fs_table_lookup(path, FS_MOUNT_POINT);
> +		if (!fsp)
> +			memset(fs_path, 0, sizeof(*fs_path));
> +		else
> +			*fs_path = *fsp;
> +	}
>  	return fd;
>  }
>  
> @@ -126,7 +136,8 @@ addfile(
>  	char		*name,
>  	int		fd,
>  	xfs_fsop_geom_t	*geometry,
> -	int		flags)
> +	int		flags,
> +	struct fs_path	*fs_path)
>  {
>  	char		*filename;
>  
> @@ -154,6 +165,7 @@ addfile(
>  	file->flags = flags;
>  	file->name = filename;
>  	file->geom = *geometry;
> +	file->fs_path = *fs_path;
>  	return 0;
>  }
>  
> @@ -195,6 +207,7 @@ open_f(
>  	char		*sp;
>  	mode_t		mode = 0600;
>  	xfs_fsop_geom_t	geometry = { 0 };
> +	struct fs_path	fsp;
>  
>  	if (argc == 1) {
>  		if (file)
> @@ -257,14 +270,14 @@ open_f(
>  		return -1;
>  	}
>  
> -	fd = openfile(argv[optind], &geometry, flags, mode);
> +	fd = openfile(argv[optind], &geometry, flags, mode, &fsp);
>  	if (fd < 0)
>  		return 0;
>  
>  	if (!platform_test_xfs_fd(fd))
>  		flags |= IO_FOREIGN;
>  
> -	addfile(argv[optind], fd, &geometry, flags);
> +	addfile(argv[optind], fd, &geometry, flags, &fsp);
>  	return 0;
>  }
>  
> diff --git a/io/pwrite.c b/io/pwrite.c
> index 7c0bb7f..1c5dfca 100644
> --- a/io/pwrite.c
> +++ b/io/pwrite.c
> @@ -357,7 +357,7 @@ pwrite_f(
>  		return 0;
>  
>  	c = IO_READONLY | (dflag ? IO_DIRECT : 0);
> -	if (infile && ((fd = openfile(infile, NULL, c, 0)) < 0))
> +	if (infile && ((fd = openfile(infile, NULL, c, 0, NULL)) < 0))
>  		return 0;
>  
>  	gettimeofday(&t1, NULL);
> diff --git a/io/reflink.c b/io/reflink.c
> index fe05d1e..f584e8f 100644
> --- a/io/reflink.c
> +++ b/io/reflink.c
> @@ -154,7 +154,7 @@ dedupe_f(
>  		return 0;
>  	}
>  
> -	fd = openfile(infile, NULL, IO_READONLY, 0);
> +	fd = openfile(infile, NULL, IO_READONLY, 0, NULL);
>  	if (fd < 0)
>  		return 0;
>  
> @@ -278,7 +278,7 @@ reflink_f(
>  	}
>  
>  clone_all:
> -	fd = openfile(infile, NULL, IO_READONLY, 0);
> +	fd = openfile(infile, NULL, IO_READONLY, 0, NULL);
>  	if (fd < 0)
>  		return 0;
>  
> diff --git a/io/sendfile.c b/io/sendfile.c
> index edd31c9..063fa7f 100644
> --- a/io/sendfile.c
> +++ b/io/sendfile.c
> @@ -115,7 +115,7 @@ sendfile_f(
>  
>  	if (!infile)
>  		fd = filetable[fd].fd;
> -	else if ((fd = openfile(infile, NULL, IO_READONLY, 0)) < 0)
> +	else if ((fd = openfile(infile, NULL, IO_READONLY, 0, NULL)) < 0)
>  		return 0;
>  
>  	if (optind == argc - 2) {
> diff --git a/man/man8/xfs_io.8 b/man/man8/xfs_io.8
> index 29a036c..bd8af47 100644
> --- a/man/man8/xfs_io.8
> +++ b/man/man8/xfs_io.8
> @@ -301,6 +301,72 @@ ioctl.  Options behave as described in the
>  .BR xfs_bmap (8)
>  manual page.
>  .TP
> +.BI "fsmap [ \-d | \-l | \-r ] [ \-v ] [ \-n " nx " ] [ " start " ] [ " end " ]
> +Prints the mapping of disk blocks used by a filesystem.
> +The map lists each extent used by files, allocation group metadata,
> +journalling logs, and static filesystem metadata, as well as any
> +regions that are unused.
> +Each line of the listings takes the following form:
> +.PP
> +.RS
> +.IR extent ": " major ":" minor " [" startblock .. endblock "]: " owner " " startoffset .. endoffset " " length
> +.PP
> +Static filesystem metadata, allocation group metadata, btrees,
> +journalling logs, and free space are marked by replacing the
> +.IR startoffset .. endoffset
> +with the appropriate marker.
> +All blocks, offsets, and lengths are specified in units of 512-byte
> +blocks, no matter what the filesystem's block size is.
> +The optional
> +.I start
> +and
> +.I end
> +arguments can be used to constrain the output to a particular range of
> +disk blocks.
> +.RE
> +.RS 1.0i
> +.PD 0
> +.TP
> +.BI \-d
> +Display only extents from the data device.
> +This option only applies for XFS filesystems.
> +.TP
> +.BI \-l
> +Display only extents from the external log device.
> +This option only applies to XFS filesystems.
> +.TP
> +.BI \-r
> +Display only extents from the realtime device.
> +This option only applies to XFS filesystems.
> +.TP
> +.BI \-n " num_extents"
> +If this option is given,
> +.B xfs_fsmap
> +obtains the extent list of the file in groups of
> +.I num_extents
> +extents.
> +In the absence of
> +.BR \-n ", " xfs_fsmap
> +queries the system for the number of extents in the filesystem and uses
> +that value to compute the group size.
> +.TP
> +.B \-v
> +Shows verbose information.
> +When this flag is specified, additional AG specific information is
> +appended to each line in the following form:
> +.IP
> +.RS 1.2i
> +.IR agno " (" startagblock .. endagblock ") " nblocks " " flags
> +.RE
> +.IP
> +A second
> +.B \-v
> +option will print out the
> +.I flags
> +legend.
> +.RE
> +.PD
> +.TP
>  .BI "extsize [ \-R | \-D ] [ " value " ]"
>  Display and/or modify the preferred extent size used when allocating
>  space for the currently open file. If the
> 
> --
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> 
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Darrick J. Wong June 14, 2017, 12:23 a.m. UTC | #2

On Tue, Jun 13, 2017 at 05:20:28PM -0500, Eric Sandeen wrote:
> On 6/2/17 2:51 PM, Darrick J. Wong wrote:
> > From: Darrick J. Wong <[e-mail]>
> > 
> > Signed-off-by: Darrick J. Wong <[e-mail]>
> 
> Sorry Darrick, lots more here that I missed the first time around.
> 
> > ---
> >  io/Makefile          |    7 +
> >  io/copy_file_range.c |    2 
> >  io/encrypt.c         |    1 
> >  io/fsmap.c           |  549 ++++++++++++++++++++++++++++++++++++++++++++++++++
> >  io/init.c            |    8 +
> >  io/io.h              |   14 +
> >  io/open.c            |   21 ++
> >  io/pwrite.c          |    2 
> >  io/reflink.c         |    4 
> >  io/sendfile.c        |    2 
> >  man/man8/xfs_io.8    |   66 ++++++
> >  11 files changed, 663 insertions(+), 13 deletions(-)
> >  create mode 100644 io/fsmap.c
> > 
> > 
> > diff --git a/io/Makefile b/io/Makefile
> > index 435ccff..47b0a66 100644
> > --- a/io/Makefile
> > +++ b/io/Makefile
> > @@ -99,6 +99,13 @@ ifeq ($(HAVE_MREMAP),yes)
> >  LCFLAGS += -DHAVE_MREMAP
> >  endif
> >  
> > +# On linux we get fsmap from the system or define it ourselves
> > +# so include this based on platform type.  If this reverts to only
> > +# the autoconf check w/o local definition, change to testing HAVE_GETFSMAP
> > +ifeq ($(PKG_PLATFORM),linux)
> > +CFILES += fsmap.c
> > +endif
> > +
> >  default: depend $(LTCOMMAND)
> >  
> >  include $(BUILDRULES)
> > diff --git a/io/copy_file_range.c b/io/copy_file_range.c
> > index 249c649..d1dfc5a 100644
> > --- a/io/copy_file_range.c
> > +++ b/io/copy_file_range.c
> > @@ -121,7 +121,7 @@ copy_range_f(int argc, char **argv)
> >  	if (optind != argc - 1)
> >  		return command_usage(&copy_range_cmd);
> >  
> > -	fd = openfile(argv[optind], NULL, IO_READONLY, 0);
> > +	fd = openfile(argv[optind], NULL, IO_READONLY, 0, NULL);
> >  	if (fd < 0)
> >  		return 0;
> >  
> > diff --git a/io/encrypt.c b/io/encrypt.c
> > index d844c5e..26ab97c 100644
> > --- a/io/encrypt.c
> > +++ b/io/encrypt.c
> > @@ -20,6 +20,7 @@
> >  #include "platform_defs.h"
> >  #include "command.h"
> >  #include "init.h"
> > +#include "path.h"
> >  #include "io.h"
> >  
> >  #ifndef ARRAY_SIZE
> > diff --git a/io/fsmap.c b/io/fsmap.c
> > new file mode 100644
> > index 0000000..1f4de81
> > --- /dev/null
> > +++ b/io/fsmap.c
> > @@ -0,0 +1,549 @@
> > +/*
> > + * Copyright (C) 2017 Oracle.  All Rights Reserved.
> > + *
> > + * Author: Darrick J. Wong <[e-mail]>
> > + *
> > + * This program is free software; you can redistribute it and/or
> > + * modify it under the terms of the GNU General Public License
> > + * as published by the Free Software Foundation; either version 2
> > + * of the License, or (at your option) any later version.
> > + *
> > + * This program is distributed in the hope that it would be useful,
> > + * but WITHOUT ANY WARRANTY; without even the implied warranty of
> > + * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
> > + * GNU General Public License for more details.
> > + *
> > + * You should have received a copy of the GNU General Public License
> > + * along with this program; if not, write the Free Software Foundation,
> > + * Inc.,  51 Franklin St, Fifth Floor, Boston, MA  02110-1301, USA.
> > + */
> > +#include "platform_defs.h"
> > +#include "command.h"
> > +#include "init.h"
> > +#include "path.h"
> > +#include "io.h"
> > +#include "input.h"
> > +
> > +static cmdinfo_t	fsmap_cmd;
> > +static dev_t		xfs_data_dev;
> > +
> > +static void
> > +fsmap_help(void)
> > +{
> > +	printf(_(
> > +"\n"
> > +" Prints the block mapping for a filesystem"
> > +"\n"
> > +" Example:\n"
> > +" 'fsmap [-d|-l|-r] [-v] [-n nr] [startoff] [endoff]' - tabular format verbose map, including unwritten extents\n"
> 
> Whoops, I missed this the first time, that's a restatement of all options,
> not an example.
> 
> (Or I'd probably just drop it, I don't think an example is needed
> or useful, but as you like it... I guess it's modeled on fiemap)

Yeah, it's unnecessary and redundant.  I'll remove it.

> > +"\n"
> > +" fsmap prints the map of disk blocks used by the whole filesystem.\n"
> > +" When possible, owner and offset information will be included in the\n"
> > +" sapce report.\n"
> > +"\n"
> > +" By default, each line of the listing takes the following form:\n"
> > +"     extent: [startoffset..endoffset] owner startblock..endblock\n"
> 
> Hm, no:
> 
> 	0: 8:17 [0..1175]: unknown 1176 blocks
> 	1: 8:17 [1176..1183]: free space 8 blocks
> 
> manpage gets it right:
> 
> extent: major:minor [startblock..endblock]: owner startoffset..endoffset length
> 
> (I might drop the last "blocks"... is it useful?  fiemap doesn't use it)

Probably came from the bmap command, but yes, it's redundant since we
already state that the numbers are in units of blocks.

I'll update the help screen to list the correct fields.

> Sigh, sorry for missing stuff on the first round.
> 
> OK fiemap prints a header with -v ...
> 
> # io/xfs_io -c "fiemap -v" /mnt/test/junk
> /mnt/test/junk:
>  EXT: FILE-OFFSET      BLOCK-RANGE      TOTAL FLAGS
>    0: [0..7]:          hole                 8
>    1: [8..39]:         5936..5967          32   0x0
> 
> I think that'd be useful here, too ... oh, bug.  see below.  (s/nr == 0/*nr == 0/)

Got it.

> > +" The owner field is either an inode number or a special value.\n"
> > +" All the file offsets and disk blocks are in units of 512-byte blocks.\n"
> > +" -d -- query only the data device.\n"
> 
> (this is the default, yes?)

Yes.

> > +" -l -- query only the log device.\n"
> 
> Hm, with an external log I get:
> 
> xfs_io> fsmap -l
> 	0: 7:7 [0..2097151]: journalling log 2097152 blocks
> 
> but an internal log does not show those blocks in the output, should it?

It will if you have rmapbt=1.  Maybe the kernel should report the owner
of an external log as 'unknown' if the caller doesn't have
CAP_SYS_ADMIN, similar to how we don't report specific owners for the
data device.

> > +" -r -- query only the realtime device.\n"
> > +" -n -- query n extents.\n"
> 
> -n doesn't seem to work as described:
> 
> # io/xfs_io -c "fsmap -n 2" /mnt/test
> 	0: 8:17 [0..1175]: unknown 1176 blocks
> 	1: 8:17 [1176..1183]: free space 8 blocks
> 	2: 8:17 [1184..1327]: unknown 144 blocks
> 	3: 8:17 [1328..1343]: free space 16 blocks
> 
> Oh, it's "at a time" - so help text needs to be fixed to reflect that it's 
> the size of each query, not the total number queried.

Yes.  Will fix the documentation.

> > +" -v -- Verbose information, specify ag info.  Show flags legend on 2nd -v\n"
> 
> (and FILE-OFFSET of each owner?)
> 
> There are no flags printed AFAICT, and no different behavior with -vv...
> but that seems broken somewhere.
> 
> Oh, it looks like if no flags are (will be?) printed we skip the column
> and the legend.  That seems a little odd to me... is it intentional?

bmap doesn't show the legend unless any of the flags are used, so fsmap
behaves similarly.

> > +"\n"));
> > +}
> > +
> > +#define OWNER_BUF_SZ	32
> > +static const char *
> > +special_owner(
> > +	int64_t		owner,
> > +	char		*buf)
> > +{
> > +	switch (owner) {
> > +	case XFS_FMR_OWN_FREE:
> > +		return _("free space");
> 
> (Aside: I wonder if there's any way to avoid spaces in the owner field,
> so that awk can easily parse the result...?  Not sure how that'd look,
> but it'd make it a lot more useful when presented with thousands of
> records)

Well, a few options come to mind -- adding a machine-friendly format,
enclosing the owner names with spaces for easier parsing, or stuffing
in weird nonbreaking space sequences (yuck).  I'm partial to the second.

> > +	case XFS_FMR_OWN_UNKNOWN:
> > +		return _("unknown");
> > +	case XFS_FMR_OWN_FS:
> > +		return _("static fs metadata");
> > +	case XFS_FMR_OWN_LOG:
> > +		return _("journalling log");
> > +	case XFS_FMR_OWN_AG:
> > +		return _("per-AG metadata");
> > +	case XFS_FMR_OWN_INOBT:
> > +		return _("inode btree");
> > +	case XFS_FMR_OWN_INODES:
> > +		return _("inodes");
> > +	case XFS_FMR_OWN_REFC:
> > +		return _("refcount btree");
> > +	case XFS_FMR_OWN_COW:
> > +		return _("cow reservation");
> > +	case XFS_FMR_OWN_DEFECTIVE:
> > +		return _("defective");
> > +	default:
> > +		snprintf(buf, OWNER_BUF_SZ, _("special %u:%u"),
> > +				FMR_OWNER_TYPE(owner), FMR_OWNER_CODE(owner));
> > +		return buf;
> > +	}
> > +}
> > +
> > +static void
> > +dump_map(
> > +	unsigned long long	*nr,
> > +	struct fsmap_head	*head)
> > +{
> > +	unsigned long long	i;
> > +	struct fsmap		*p;
> > +	char			owner[OWNER_BUF_SZ];
> > +
> > +	for (i = 0, p = head->fmh_recs; i < head->fmh_entries; i++, p++) {
> > +		printf("\t%llu: %u:%u [%lld..%lld]: ", i + (*nr),
> > +			major(p->fmr_device), minor(p->fmr_device),
> > +			(long long)BTOBBT(p->fmr_physical),
> > +			(long long)BTOBBT(p->fmr_physical + p->fmr_length - 1));
> > +		if (p->fmr_flags & FMR_OF_SPECIAL_OWNER)
> > +			printf("%s", special_owner(p->fmr_owner, owner));
> > +		else if (p->fmr_flags & FMR_OF_EXTENT_MAP)
> > +			printf(_("inode %lld extent map"),
> > +				(long long) p->fmr_owner);
> > +		else
> > +			printf(_("inode %lld %lld..%lld"),
> > +				(long long)p->fmr_owner,
> > +				(long long)BTOBBT(p->fmr_offset),
> > +				(long long)BTOBBT(p->fmr_offset + p->fmr_length - 1));
> > +		printf(_(" %lld blocks\n"),
> > +			(long long)BTOBBT(p->fmr_length));
> > +	}
> > +
> > +	(*nr) += head->fmh_entries;
> > +}
> > +
> > +/*
> > + * Verbose mode displays:
> > + *   extent: major:minor [startblock..endblock]: startoffset..endoffset \
> > + *	ag# (agoffset..agendoffset) totalbbs flags
> > + */
> > +#define MINRANGE_WIDTH	16
> > +#define MINAG_WIDTH	2
> > +#define MINTOT_WIDTH	5
> > +#define NFLG		7		/* count of flags */
> > +#define	FLG_NULL	00000000	/* Null flag */
> > +#define	FLG_ATTR_FORK	01000000	/* attribute fork */
> > +#define	FLG_SHARED	00100000	/* shared extent */
> > +#define	FLG_PRE		00010000	/* Unwritten extent */
> > +#define	FLG_BSU		00001000	/* Not on begin of stripe unit  */
> > +#define	FLG_ESU		00000100	/* Not on end   of stripe unit  */
> > +#define	FLG_BSW		00000010	/* Not on begin of stripe width */
> > +#define	FLG_ESW		00000001	/* Not on end   of stripe width */
> > +static void
> > +dump_map_verbose(
> > +	unsigned long long	*nr,
> > +	struct fsmap_head	*head,
> > +	bool			*dumped_flags,
> > +	struct xfs_fsop_geom	*fsgeo)
> > +{
> > +	unsigned long long	i;
> > +	struct fsmap		*p;
> > +	int			agno;
> > +	off64_t			agoff, bperag;
> > +	int			foff_w, boff_w, aoff_w, tot_w, agno_w, own_w;
> > +	int			nr_w, dev_w;
> > +	char			rbuf[32], bbuf[32], abuf[32], obuf[32];
> > +	char			nbuf[32], dbuf[32], gbuf[32];
> > +	char			owner[OWNER_BUF_SZ];
> > +	int			sunit, swidth;
> > +	int			flg = 0;
> > +
> > +	foff_w = boff_w = aoff_w = own_w = MINRANGE_WIDTH;
> > +	dev_w = 3;
> > +	nr_w = 4;
> > +	tot_w = MINTOT_WIDTH;
> > +	bperag = (off64_t)fsgeo->agblocks *
> > +		  (off64_t)fsgeo->blocksize;
> > +	sunit = (fsgeo->sunit * fsgeo->blocksize);
> > +	swidth = (fsgeo->swidth * fsgeo->blocksize);
> > +
> > +	/*
> > +	 * Go through the extents and figure out the width
> > +	 * needed for all columns.
> > +	 */
> > +	for (i = 0, p = head->fmh_recs; i < head->fmh_entries; i++, p++) {
> > +		if (p->fmr_flags & FMR_OF_PREALLOC ||
> > +		    p->fmr_flags & FMR_OF_ATTR_FORK ||
> > +		    p->fmr_flags & FMR_OF_SHARED)
> > +			flg = 1;
> > +		if (sunit &&
> > +		    (p->fmr_physical  % sunit != 0 ||
> > +		     ((p->fmr_physical + p->fmr_length) % sunit) != 0 ||
> > +		     p->fmr_physical % swidth != 0 ||
> > +		     ((p->fmr_physical + p->fmr_length) % swidth) != 0))
> > +			flg = 1;
> > +		if (flg)
> > +			*dumped_flags = true;
> > +		snprintf(nbuf, sizeof(nbuf), "%llu", (*nr) + i);
> > +		nr_w = max(nr_w, strlen(nbuf));
> > +		if (head->fmh_oflags & FMH_OF_DEV_T)
> > +			snprintf(dbuf, sizeof(dbuf), "%u:%u",
> > +				major(p->fmr_device),
> > +				minor(p->fmr_device));
> > +		else
> > +			snprintf(dbuf, sizeof(dbuf), "0x%x", p->fmr_device);
> > +		dev_w = max(dev_w, strlen(dbuf));
> > +		snprintf(bbuf, sizeof(bbuf), "[%lld..%lld]:",
> > +			(long long)BTOBBT(p->fmr_physical),
> > +			(long long)BTOBBT(p->fmr_physical + p->fmr_length - 1));
> > +		boff_w = max(boff_w, strlen(bbuf));
> > +		if (p->fmr_flags & FMR_OF_SPECIAL_OWNER)
> > +			own_w = max(own_w, strlen(
> > +					special_owner(p->fmr_owner, owner)));
> > +		else {
> > +			snprintf(obuf, sizeof(obuf), "%lld",
> > +				(long long)p->fmr_owner);
> > +			own_w = max(own_w, strlen(obuf));
> > +		}
> > +		if (p->fmr_flags & FMR_OF_EXTENT_MAP)
> > +			foff_w = max(foff_w, strlen(_("extent_map")));
> > +		else if (p->fmr_flags & FMR_OF_SPECIAL_OWNER)
> > +			;
> > +		else {
> > +			snprintf(rbuf, sizeof(rbuf), "%lld..%lld",
> > +				(long long)BTOBBT(p->fmr_offset),
> > +				(long long)BTOBBT(p->fmr_offset + p->fmr_length - 1));
> > +			foff_w = max(foff_w, strlen(rbuf));
> > +		}
> > +		if (p->fmr_device == xfs_data_dev) {
> > +			agno = p->fmr_physical / bperag;
> > +			agoff = p->fmr_physical - (agno * bperag);
> > +			snprintf(abuf, sizeof(abuf),
> > +				"(%lld..%lld)",
> > +				(long long)BTOBBT(agoff),
> > +				(long long)BTOBBT(agoff + p->fmr_length - 1));
> > +		} else
> > +			abuf[0] = 0;
> > +		aoff_w = max(aoff_w, strlen(abuf));
> > +		tot_w = max(tot_w,
> > +			numlen(BTOBBT(p->fmr_length), 10));
> > +	}
> > +	agno_w = max(MINAG_WIDTH, numlen(fsgeo->agcount, 10));
> > +	if (nr == 0)
> 
> if (*nr == 0)

Oops, fixed.

> > +		printf("%*s: %-*s %-*s %-*s %-*s %*s %-*s %*s%s\n",
> > +			nr_w, _("EXT"),
> > +			dev_w, _("DEV"),
> > +			boff_w, _("BLOCK-RANGE"),
> > +			own_w, _("OWNER"),
> > +			foff_w, _("FILE-OFFSET"),
> > +			agno_w, _("AG"),
> > +			aoff_w, _("AG-OFFSET"),
> > +			tot_w, _("TOTAL"),
> > +			flg ? _(" FLAGS") : "");
> > +	for (i = 0, p = head->fmh_recs; i < head->fmh_entries; i++, p++) {
> > +		flg = FLG_NULL;
> > +		if (p->fmr_flags & FMR_OF_PREALLOC)
> > +			flg |= FLG_PRE;
> > +		if (p->fmr_flags & FMR_OF_ATTR_FORK)
> > +			flg |= FLG_ATTR_FORK;
> > +		if (p->fmr_flags & FMR_OF_SHARED)
> > +			flg |= FLG_SHARED;
> > +		/*
> > +		 * If striping enabled, determine if extent starts/ends
> > +		 * on a stripe unit boundary.
> > +		 */
> > +		if (sunit) {
> > +			if (p->fmr_physical  % sunit != 0)
> > +				flg |= FLG_BSU;
> > +			if (((p->fmr_physical +
> > +			      p->fmr_length ) % sunit ) != 0)
> > +				flg |= FLG_ESU;
> > +			if (p->fmr_physical % swidth != 0)
> > +				flg |= FLG_BSW;
> > +			if (((p->fmr_physical +
> > +			      p->fmr_length ) % swidth ) != 0)
> > +				flg |= FLG_ESW;
> > +		}
> > +		if (head->fmh_oflags & FMH_OF_DEV_T)
> > +			snprintf(dbuf, sizeof(dbuf), "%u:%u",
> > +				major(p->fmr_device),
> > +				minor(p->fmr_device));
> > +		else
> > +			snprintf(dbuf, sizeof(dbuf), "0x%x", p->fmr_device);
> > +		snprintf(bbuf, sizeof(bbuf), "[%lld..%lld]:",
> > +			(long long)BTOBBT(p->fmr_physical),
> > +			(long long)BTOBBT(p->fmr_physical + p->fmr_length - 1));
> > +		if (p->fmr_flags & FMR_OF_SPECIAL_OWNER) {
> > +			snprintf(obuf, sizeof(obuf), "%s",
> > +				special_owner(p->fmr_owner, owner));
> > +			snprintf(rbuf, sizeof(rbuf), " ");
> > +		} else {
> > +			snprintf(obuf, sizeof(obuf), "%lld",
> > +				(long long)p->fmr_owner);
> > +			snprintf(rbuf, sizeof(rbuf), "%lld..%lld",
> > +				(long long)BTOBBT(p->fmr_offset),
> > +				(long long)BTOBBT(p->fmr_offset + p->fmr_length - 1));
> > +		}
> > +		if (p->fmr_device == xfs_data_dev) {
> > +			agno = p->fmr_physical / bperag;
> > +			agoff = p->fmr_physical - (agno * bperag);
> > +			snprintf(abuf, sizeof(abuf),
> > +				"(%lld..%lld)",
> > +				(long long)BTOBBT(agoff),
> > +				(long long)BTOBBT(agoff + p->fmr_length - 1));
> > +			snprintf(gbuf, sizeof(gbuf),
> > +				"%lld",
> > +				(long long)agno);
> > +		} else {
> > +			abuf[0] = 0;
> > +			gbuf[0] = 0;
> > +		}
> > +		if (p->fmr_flags & FMR_OF_EXTENT_MAP)
> > +			printf("%*llu: %-*s %-*s %-*s %-*s %-*s %-*s %*lld\n",
> > +				nr_w, (*nr) + i,
> > +				dev_w, dbuf,
> > +				boff_w, bbuf,
> > +				own_w, obuf,
> > +				foff_w, _("extent map"),
> > +				agno_w, gbuf,
> > +				aoff_w, abuf,
> > +				tot_w, (long long)BTOBBT(p->fmr_length));
> > +		else {
> > +			printf("%*llu: %-*s %-*s %-*s %-*s", nr_w, (*nr) + i,
> > +				dev_w, dbuf, boff_w, bbuf, own_w, obuf,
> > +				foff_w, rbuf);
> > +			printf(" %-*s %-*s", agno_w, gbuf,
> > +				aoff_w, abuf);
> > +			printf(" %*lld", tot_w,
> > +				(long long)BTOBBT(p->fmr_length));
> > +			if (flg == FLG_NULL)
> > +				printf("\n");
> > +			else
> > +				printf(" %-*.*o\n", NFLG, NFLG, flg);
> > +		}
> > +	}
> > +
> > +	(*nr) += head->fmh_entries;
> > +}
> > +
> > +static void
> > +dump_verbose_key(void)
> > +{
> > +	printf(_(" FLAG Values:\n"));
> > +	printf(_("    %*.*o Attribute fork\n"),
> > +		NFLG+1, NFLG+1, FLG_ATTR_FORK);
> > +	printf(_("    %*.*o Shared extent\n"),
> > +		NFLG+1, NFLG+1, FLG_SHARED);
> > +	printf(_("    %*.*o Unwritten preallocated extent\n"),
> > +		NFLG+1, NFLG+1, FLG_PRE);
> > +	printf(_("    %*.*o Doesn't begin on stripe unit\n"),
> > +		NFLG+1, NFLG+1, FLG_BSU);
> > +	printf(_("    %*.*o Doesn't end   on stripe unit\n"),
> > +		NFLG+1, NFLG+1, FLG_ESU);
> > +	printf(_("    %*.*o Doesn't begin on stripe width\n"),
> > +		NFLG+1, NFLG+1, FLG_BSW);
> > +	printf(_("    %*.*o Doesn't end   on stripe width\n"),
> > +		NFLG+1, NFLG+1, FLG_ESW);
> > +}
> > +
> > +int
> > +fsmap_f(
> > +	int			argc,
> > +	char			**argv)
> > +{
> > +	struct fsmap		*p;
> > +	struct fsmap_head	*nhead;
> > +	struct fsmap_head	*head;
> > +	struct fsmap		*l, *h;
> > +	struct xfs_fsop_geom	fsgeo;
> > +	long long		start = 0;
> > +	long long		end = -1;
> > +	int			nmap_size;
> > +	int			map_size;
> > +	int			nflag = 0;
> > +	int			vflag = 0;
> > +	int			i = 0;
> > +	int			c;
> > +	unsigned long long	nr = 0;
> > +	size_t			fsblocksize, fssectsize;
> > +	struct fs_path		*fs;
> > +	static bool		tab_init;
> > +	bool			dumped_flags = false;
> > +	int			dflag, lflag, rflag;
> > +
> > +	init_cvtnum(&fsblocksize, &fssectsize);
> > +
> > +	dflag = lflag = rflag = 0;
> > +	while ((c = getopt(argc, argv, "dln:rv")) != EOF) {
> > +		switch (c) {
> > +		case 'd':	/* data device */
> > +			dflag = 1;
> > +			break;
> > +		case 'l':	/* log device */
> > +			lflag = 1;
> > +			break;
> > +		case 'n':	/* number of extents specified */
> > +			nflag = atoi(optarg);
> > +			break;
> > +		case 'r':	/* rt device */
> > +			rflag = 1;
> > +			break;
> > +		case 'v':	/* Verbose output */
> > +			vflag++;
> > +			break;
> > +		default:
> > +			return command_usage(&fsmap_cmd);
> > +		}
> > +	}
> > +
> > +	if (dflag + lflag + rflag > 1)
> > +		return command_usage(&fsmap_cmd);
> > +
> > +	if (argc > optind && dflag + lflag + rflag == 0)
> > +		return command_usage(&fsmap_cmd);
> > +
> > +	if (argc > optind) {
> > +		start = cvtnum(fsblocksize, fssectsize, argv[optind]);
> > +		if (start < 0) {
> > +			fprintf(stderr,
> > +				_("Bad rmap start_bblock %s.\n"),
> > +				argv[optind]);
> > +			return 0;
> > +		}
> > +		start <<= BBSHIFT;
> > +	}
> > +
> > +	if (argc > optind + 1) {
> > +		end = cvtnum(fsblocksize, fssectsize, argv[optind + 1]);
> > +		if (end < 0) {
> > +			fprintf(stderr,
> > +				_("Bad rmap end_bblock %s.\n"),
> > +				argv[optind + 1]);
> > +			return 0;
> > +		}
> > +		end <<= BBSHIFT;
> > +	}
> > +
> > +	if (vflag) {
> > +		c = ioctl(file->fd, XFS_IOC_FSGEOMETRY, &fsgeo);
> > +		if (c < 0) {
> > +			fprintf(stderr,
> > +				_("%s: can't get geometry [\"%s\"]: %s\n"),
> > +				progname, file->name, strerror(errno));
> > +			exitcode = 1;
> > +			return 0;
> > +		}
> > +	}
> > +
> > +	map_size = nflag ? nflag : 131072 / sizeof(struct fsmap);
> 
> Manpage, below:
> 
> "In the absence of -n, xfs_fsmap queries the system for the number of extents in the filesystem
> and uses that value to compute the group size."
> 
> Looks hard-coded to 131072, no?

Yes.  It used to behave as specified, but it was very slow to rake every
rmap record in the system twice, so I changed it to 131072 and evidently
forgot to update the manpage.

--D

> > +	head = malloc(fsmap_sizeof(map_size));
> > +	if (head == NULL) {
> > +		fprintf(stderr, _("%s: malloc of %zu bytes failed.\n"),
> > +			progname, fsmap_sizeof(map_size));
> > +		exitcode = 1;
> > +		return 0;
> > +	}
> > +
> > +	memset(head, 0, sizeof(*head));
> > +	l = head->fmh_keys;
> > +	h = head->fmh_keys + 1;
> > +	if (dflag) {
> > +		l->fmr_device = h->fmr_device = file->fs_path.fs_datadev;
> > +	} else if (lflag) {
> > +		l->fmr_device = h->fmr_device = file->fs_path.fs_logdev;
> > +	} else if (rflag) {
> > +		l->fmr_device = h->fmr_device = file->fs_path.fs_rtdev;
> > +	} else {
> > +		l->fmr_device = 0;
> > +		h->fmr_device = UINT_MAX;
> > +	}
> > +	l->fmr_physical = start;
> > +	h->fmr_physical = end;
> > +	h->fmr_owner = ULLONG_MAX;
> > +	h->fmr_flags = UINT_MAX;
> > +	h->fmr_offset = ULLONG_MAX;
> > +
> > +	/* Count mappings */
> > +	if (!nflag) {
> > +		head->fmh_count = 0;
> > +		i = ioctl(file->fd, FS_IOC_GETFSMAP, head);
> > +		if (i < 0) {
> > +			fprintf(stderr, _("%s: xfsctl(XFS_IOC_GETFSMAP)"
> > +				" iflags=0x%x [\"%s\"]: %s\n"),
> > +				progname, head->fmh_iflags, file->name,
> > +				strerror(errno));
> > +			free(head);
> > +			exitcode = 1;
> > +			return 0;
> > +		}
> > +		if (head->fmh_entries > map_size + 2) {
> > +			map_size = 11ULL * head->fmh_entries / 10;
> > +			nmap_size = map_size > (1 << 24) ? (1 << 24) : map_size;
> > +			nhead = realloc(head, fsmap_sizeof(nmap_size));
> > +			if (nhead == NULL) {
> > +				fprintf(stderr,
> > +					_("%s: cannot realloc %zu bytes\n"),
> > +					progname, fsmap_sizeof(nmap_size));
> > +			} else {
> > +				head = nhead;
> > +				map_size = nmap_size;
> > +			}
> > +		}
> > +	}
> > +
> > +	/*
> > +	 * If this is an XFS filesystem, remember the data device.
> > +	 * (We report AG number/block for data device extents on XFS).
> > +	 */
> > +	if (!tab_init) {
> > +		fs_table_initialise(0, NULL, 0, NULL);
> > +		tab_init = true;
> > +	}
> > +	fs = fs_table_lookup(file->name, FS_MOUNT_POINT);
> > +	xfs_data_dev = fs ? fs->fs_datadev : 0;
> > +
> > +	head->fmh_count = map_size;
> > +	do {
> > +		/* Get some extents */
> > +		i = ioctl(file->fd, FS_IOC_GETFSMAP, head);
> > +		if (i < 0) {
> > +			fprintf(stderr, _("%s: xfsctl(XFS_IOC_GETFSMAP)"
> > +				" iflags=0x%x [\"%s\"]: %s\n"),
> > +				progname, head->fmh_iflags, file->name,
> > +				strerror(errno));
> > +			free(head);
> > +			exitcode = 1;
> > +			return 0;
> > +		}
> > +
> > +		if (head->fmh_entries == 0)
> > +			break;
> > +
> > +		if (!vflag)
> > +			dump_map(&nr, head);
> > +		else
> > +			dump_map_verbose(&nr, head, &dumped_flags, &fsgeo);
> > +
> > +		p = &head->fmh_recs[head->fmh_entries - 1];
> > +		if (p->fmr_flags & FMR_OF_LAST)
> > +			break;
> > +		fsmap_advance(head);
> > +	} while (true);
> > +
> > +	if (dumped_flags)
> > +		dump_verbose_key();
> > +
> > +	free(head);
> > +	return 0;
> > +}
> > +
> > +void
> > +fsmap_init(void)
> > +{
> > +	fsmap_cmd.name = "fsmap";
> > +	fsmap_cmd.cfunc = fsmap_f;
> > +	fsmap_cmd.argmin = 0;
> > +	fsmap_cmd.argmax = -1;
> > +	fsmap_cmd.flags = CMD_NOMAP_OK | CMD_FLAG_FOREIGN_OK;
> > +	fsmap_cmd.args = _("[-d|-l|-r] [-v] [-n nx] [start] [end]");
> > +	fsmap_cmd.oneline = _("print filesystem mapping for a range of blocks");
> > +	fsmap_cmd.help = fsmap_help;
> > +
> > +	add_command(&fsmap_cmd);
> > +}
> > diff --git a/io/init.c b/io/init.c
> > index c15a1e1..20d5f80 100644
> > --- a/io/init.c
> > +++ b/io/init.c
> > @@ -66,6 +66,7 @@ init_commands(void)
> >  	file_init();
> >  	flink_init();
> >  	freeze_init();
> > +	fsmap_init();
> >  	fsync_init();
> >  	getrusage_init();
> >  	help_init();
> > @@ -139,6 +140,7 @@ init(
> >  	char		*sp;
> >  	mode_t		mode = 0600;
> >  	xfs_fsop_geom_t	geometry = { 0 };
> > +	struct fs_path	fsp;
> >  
> >  	progname = basename(argv[0]);
> >  	setlocale(LC_ALL, "");
> > @@ -148,6 +150,7 @@ init(
> >  	pagesize = getpagesize();
> >  	gettimeofday(&stopwatch, NULL);
> >  
> > +	fs_table_initialise(0, NULL, 0, NULL);
> >  	while ((c = getopt(argc, argv, "ac:C:dFfim:p:nrRstTVx")) != EOF) {
> >  		switch (c) {
> >  		case 'a':
> > @@ -212,11 +215,12 @@ init(
> >  	}
> >  
> >  	while (optind < argc) {
> > -		if ((c = openfile(argv[optind], &geometry, flags, mode)) < 0)
> > +		c = openfile(argv[optind], &geometry, flags, mode, &fsp);
> > +		if (c < 0)
> >  			exit(1);
> >  		if (!platform_test_xfs_fd(c))
> >  			flags |= IO_FOREIGN;
> > -		if (addfile(argv[optind], c, &geometry, flags) < 0)
> > +		if (addfile(argv[optind], c, &geometry, flags, &fsp) < 0)
> >  			exit(1);
> >  		optind++;
> >  	}
> > diff --git a/io/io.h b/io/io.h
> > index 952bdb8..6a0fe65 100644
> > --- a/io/io.h
> > +++ b/io/io.h
> > @@ -17,6 +17,7 @@
> >   */
> >  
> >  #include "xfs.h"
> > +#include "path.h"
> >  
> >  /*
> >   * Read/write patterns (default is always "forward")
> > @@ -47,6 +48,7 @@ typedef struct fileio {
> >  	int		flags;		/* flags describing file state */
> >  	char		*name;		/* file name at time of open */
> >  	xfs_fsop_geom_t	geom;		/* XFS filesystem geometry */
> > +	struct fs_path	fs_path;	/* XFS path information */
> >  } fileio_t;
> >  
> >  extern fileio_t		*filetable;	/* open file table */
> > @@ -76,8 +78,10 @@ extern void *check_mapping_range(mmap_region_t *, off64_t, size_t, int);
> >   */
> >  
> >  extern off64_t		filesize(void);
> > -extern int		openfile(char *, xfs_fsop_geom_t *, int, mode_t);
> > -extern int		addfile(char *, int , xfs_fsop_geom_t *, int);
> > +extern int		openfile(char *, xfs_fsop_geom_t *, int, mode_t,
> > +				 struct fs_path *);
> > +extern int		addfile(char *, int , xfs_fsop_geom_t *, int,
> > +				struct fs_path *);
> >  extern void		printxattr(uint, int, int, const char *, int, int);
> >  
> >  extern unsigned int	recurse_all;
> > @@ -174,3 +178,9 @@ extern void		readdir_init(void);
> >  extern void		reflink_init(void);
> >  
> >  extern void		cowextsize_init(void);
> > +
> > +#ifdef HAVE_GETFSMAP
> > +extern void		fsmap_init(void);
> > +#else
> > +# define fsmap_init()	do { } while (0)
> > +#endif
> > diff --git a/io/open.c b/io/open.c
> > index 2ed55cf..b50f068 100644
> > --- a/io/open.c
> > +++ b/io/open.c
> > @@ -52,8 +52,10 @@ openfile(
> >  	char		*path,
> >  	xfs_fsop_geom_t	*geom,
> >  	int		flags,
> > -	mode_t		mode)
> > +	mode_t		mode,
> > +	struct fs_path	*fs_path)
> >  {
> > +	struct fs_path	*fsp;
> >  	int		fd;
> >  	int		oflags;
> >  
> > @@ -118,6 +120,14 @@ openfile(
> >  			}
> >  		}
> >  	}
> > +
> > +	if (fs_path) {
> > +		fsp = fs_table_lookup(path, FS_MOUNT_POINT);
> > +		if (!fsp)
> > +			memset(fs_path, 0, sizeof(*fs_path));
> > +		else
> > +			*fs_path = *fsp;
> > +	}
> >  	return fd;
> >  }
> >  
> > @@ -126,7 +136,8 @@ addfile(
> >  	char		*name,
> >  	int		fd,
> >  	xfs_fsop_geom_t	*geometry,
> > -	int		flags)
> > +	int		flags,
> > +	struct fs_path	*fs_path)
> >  {
> >  	char		*filename;
> >  
> > @@ -154,6 +165,7 @@ addfile(
> >  	file->flags = flags;
> >  	file->name = filename;
> >  	file->geom = *geometry;
> > +	file->fs_path = *fs_path;
> >  	return 0;
> >  }
> >  
> > @@ -195,6 +207,7 @@ open_f(
> >  	char		*sp;
> >  	mode_t		mode = 0600;
> >  	xfs_fsop_geom_t	geometry = { 0 };
> > +	struct fs_path	fsp;
> >  
> >  	if (argc == 1) {
> >  		if (file)
> > @@ -257,14 +270,14 @@ open_f(
> >  		return -1;
> >  	}
> >  
> > -	fd = openfile(argv[optind], &geometry, flags, mode);
> > +	fd = openfile(argv[optind], &geometry, flags, mode, &fsp);
> >  	if (fd < 0)
> >  		return 0;
> >  
> >  	if (!platform_test_xfs_fd(fd))
> >  		flags |= IO_FOREIGN;
> >  
> > -	addfile(argv[optind], fd, &geometry, flags);
> > +	addfile(argv[optind], fd, &geometry, flags, &fsp);
> >  	return 0;
> >  }
> >  
> > diff --git a/io/pwrite.c b/io/pwrite.c
> > index 7c0bb7f..1c5dfca 100644
> > --- a/io/pwrite.c
> > +++ b/io/pwrite.c
> > @@ -357,7 +357,7 @@ pwrite_f(
> >  		return 0;
> >  
> >  	c = IO_READONLY | (dflag ? IO_DIRECT : 0);
> > -	if (infile && ((fd = openfile(infile, NULL, c, 0)) < 0))
> > +	if (infile && ((fd = openfile(infile, NULL, c, 0, NULL)) < 0))
> >  		return 0;
> >  
> >  	gettimeofday(&t1, NULL);
> > diff --git a/io/reflink.c b/io/reflink.c
> > index fe05d1e..f584e8f 100644
> > --- a/io/reflink.c
> > +++ b/io/reflink.c
> > @@ -154,7 +154,7 @@ dedupe_f(
> >  		return 0;
> >  	}
> >  
> > -	fd = openfile(infile, NULL, IO_READONLY, 0);
> > +	fd = openfile(infile, NULL, IO_READONLY, 0, NULL);
> >  	if (fd < 0)
> >  		return 0;
> >  
> > @@ -278,7 +278,7 @@ reflink_f(
> >  	}
> >  
> >  clone_all:
> > -	fd = openfile(infile, NULL, IO_READONLY, 0);
> > +	fd = openfile(infile, NULL, IO_READONLY, 0, NULL);
> >  	if (fd < 0)
> >  		return 0;
> >  
> > diff --git a/io/sendfile.c b/io/sendfile.c
> > index edd31c9..063fa7f 100644
> > --- a/io/sendfile.c
> > +++ b/io/sendfile.c
> > @@ -115,7 +115,7 @@ sendfile_f(
> >  
> >  	if (!infile)
> >  		fd = filetable[fd].fd;
> > -	else if ((fd = openfile(infile, NULL, IO_READONLY, 0)) < 0)
> > +	else if ((fd = openfile(infile, NULL, IO_READONLY, 0, NULL)) < 0)
> >  		return 0;
> >  
> >  	if (optind == argc - 2) {
> > diff --git a/man/man8/xfs_io.8 b/man/man8/xfs_io.8
> > index 29a036c..bd8af47 100644
> > --- a/man/man8/xfs_io.8
> > +++ b/man/man8/xfs_io.8
> > @@ -301,6 +301,72 @@ ioctl.  Options behave as described in the
> >  .BR xfs_bmap (8)
> >  manual page.
> >  .TP
> > +.BI "fsmap [ \-d | \-l | \-r ] [ \-v ] [ \-n " nx " ] [ " start " ] [ " end " ]
> > +Prints the mapping of disk blocks used by a filesystem.
> > +The map lists each extent used by files, allocation group metadata,
> > +journalling logs, and static filesystem metadata, as well as any
> > +regions that are unused.
> > +Each line of the listings takes the following form:
> > +.PP
> > +.RS
> > +.IR extent ": " major ":" minor " [" startblock .. endblock "]: " owner " " startoffset .. endoffset " " length
> > +.PP
> > +Static filesystem metadata, allocation group metadata, btrees,
> > +journalling logs, and free space are marked by replacing the
> > +.IR startoffset .. endoffset
> > +with the appropriate marker.
> > +All blocks, offsets, and lengths are specified in units of 512-byte
> > +blocks, no matter what the filesystem's block size is.
> > +The optional
> > +.I start
> > +and
> > +.I end
> > +arguments can be used to constrain the output to a particular range of
> > +disk blocks.
> > +.RE
> > +.RS 1.0i
> > +.PD 0
> > +.TP
> > +.BI \-d
> > +Display only extents from the data device.
> > +This option only applies for XFS filesystems.
> > +.TP
> > +.BI \-l
> > +Display only extents from the external log device.
> > +This option only applies to XFS filesystems.
> > +.TP
> > +.BI \-r
> > +Display only extents from the realtime device.
> > +This option only applies to XFS filesystems.
> > +.TP
> > +.BI \-n " num_extents"
> > +If this option is given,
> > +.B xfs_fsmap
> > +obtains the extent list of the file in groups of
> > +.I num_extents
> > +extents.
> > +In the absence of
> > +.BR \-n ", " xfs_fsmap
> > +queries the system for the number of extents in the filesystem and uses
> > +that value to compute the group size.
> > +.TP
> > +.B \-v
> > +Shows verbose information.
> > +When this flag is specified, additional AG specific information is
> > +appended to each line in the following form:
> > +.IP
> > +.RS 1.2i
> > +.IR agno " (" startagblock .. endagblock ") " nblocks " " flags
> > +.RE
> > +.IP
> > +A second
> > +.B \-v
> > +option will print out the
> > +.I flags
> > +legend.
> > +.RE
> > +.PD
> > +.TP
> >  .BI "extsize [ \-R | \-D ] [ " value " ]"
> >  Display and/or modify the preferred extent size used when allocating
> >  space for the currently open file. If the
> > 
> > --
> > To unsubscribe from this list: send the line "unsubscribe linux-xfs" in
> > the body of a message to [e-mail]
> > More majordomo info at  http://vger.kernel.org/majordomo-info.html
> > 
> --
> To unsubscribe from this list: send the line "unsubscribe linux-xfs" in
> the body of a message to [e-mail]
> More majordomo info at  http://vger.kernel.org/majordomo-info.html
--
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Patch

diff --git a/io/Makefile b/io/Makefile
index 435ccff..47b0a66 100644
--- a/io/Makefile
+++ b/io/Makefile
@@ -99,6 +99,13 @@  ifeq ($(HAVE_MREMAP),yes)
 LCFLAGS += -DHAVE_MREMAP
 endif
 
+# On linux we get fsmap from the system or define it ourselves
+# so include this based on platform type.  If this reverts to only
+# the autoconf check w/o local definition, change to testing HAVE_GETFSMAP
+ifeq ($(PKG_PLATFORM),linux)
+CFILES += fsmap.c
+endif
+
 default: depend $(LTCOMMAND)
 
 include $(BUILDRULES)
diff --git a/io/copy_file_range.c b/io/copy_file_range.c
index 249c649..d1dfc5a 100644
--- a/io/copy_file_range.c
+++ b/io/copy_file_range.c
@@ -121,7 +121,7 @@  copy_range_f(int argc, char **argv)
 	if (optind != argc - 1)
 		return command_usage(&copy_range_cmd);
 
-	fd = openfile(argv[optind], NULL, IO_READONLY, 0);
+	fd = openfile(argv[optind], NULL, IO_READONLY, 0, NULL);
 	if (fd < 0)
 		return 0;
 
diff --git a/io/encrypt.c b/io/encrypt.c
index d844c5e..26ab97c 100644
--- a/io/encrypt.c
+++ b/io/encrypt.c
@@ -20,6 +20,7 @@ 
 #include "platform_defs.h"
 #include "command.h"
 #include "init.h"
+#include "path.h"
 #include "io.h"
 
 #ifndef ARRAY_SIZE
diff --git a/io/fsmap.c b/io/fsmap.c
new file mode 100644
index 0000000..1f4de81
--- /dev/null
+++ b/io/fsmap.c
@@ -0,0 +1,549 @@ 
+/*
+ * Copyright (C) 2017 Oracle.  All Rights Reserved.
+ *
+ * Author: Darrick J. Wong <[e-mail]>
+ *
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU General Public License
+ * as published by the Free Software Foundation; either version 2
+ * of the License, or (at your option) any later version.
+ *
+ * This program is distributed in the hope that it would be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, write the Free Software Foundation,
+ * Inc.,  51 Franklin St, Fifth Floor, Boston, MA  02110-1301, USA.
+ */
+#include "platform_defs.h"
+#include "command.h"
+#include "init.h"
+#include "path.h"
+#include "io.h"
+#include "input.h"
+
+static cmdinfo_t	fsmap_cmd;
+static dev_t		xfs_data_dev;
+
+static void
+fsmap_help(void)
+{
+	printf(_(
+"\n"
+" Prints the block mapping for a filesystem"
+"\n"
+" Example:\n"
+" 'fsmap [-d|-l|-r] [-v] [-n nr] [startoff] [endoff]' - tabular format verbose map, including unwritten extents\n"
+"\n"
+" fsmap prints the map of disk blocks used by the whole filesystem.\n"
+" When possible, owner and offset information will be included in the\n"
+" sapce report.\n"
+"\n"
+" By default, each line of the listing takes the following form:\n"
+"     extent: [startoffset..endoffset] owner startblock..endblock\n"
+" The owner field is either an inode number or a special value.\n"
+" All the file offsets and disk blocks are in units of 512-byte blocks.\n"
+" -d -- query only the data device.\n"
+" -l -- query only the log device.\n"
+" -r -- query only the realtime device.\n"
+" -n -- query n extents.\n"
+" -v -- Verbose information, specify ag info.  Show flags legend on 2nd -v\n"
+"\n"));
+}
+
+#define OWNER_BUF_SZ	32
+static const char *
+special_owner(
+	int64_t		owner,
+	char		*buf)
+{
+	switch (owner) {
+	case XFS_FMR_OWN_FREE:
+		return _("free space");
+	case XFS_FMR_OWN_UNKNOWN:
+		return _("unknown");
+	case XFS_FMR_OWN_FS:
+		return _("static fs metadata");
+	case XFS_FMR_OWN_LOG:
+		return _("journalling log");
+	case XFS_FMR_OWN_AG:
+		return _("per-AG metadata");
+	case XFS_FMR_OWN_INOBT:
+		return _("inode btree");
+	case XFS_FMR_OWN_INODES:
+		return _("inodes");
+	case XFS_FMR_OWN_REFC:
+		return _("refcount btree");
+	case XFS_FMR_OWN_COW:
+		return _("cow reservation");
+	case XFS_FMR_OWN_DEFECTIVE:
+		return _("defective");
+	default:
+		snprintf(buf, OWNER_BUF_SZ, _("special %u:%u"),
+				FMR_OWNER_TYPE(owner), FMR_OWNER_CODE(owner));
+		return buf;
+	}
+}
+
+static void
+dump_map(
+	unsigned long long	*nr,
+	struct fsmap_head	*head)
+{
+	unsigned long long	i;
+	struct fsmap		*p;
+	char			owner[OWNER_BUF_SZ];
+
+	for (i = 0, p = head->fmh_recs; i < head->fmh_entries; i++, p++) {
+		printf("\t%llu: %u:%u [%lld..%lld]: ", i + (*nr),
+			major(p->fmr_device), minor(p->fmr_device),
+			(long long)BTOBBT(p->fmr_physical),
+			(long long)BTOBBT(p->fmr_physical + p->fmr_length - 1));
+		if (p->fmr_flags & FMR_OF_SPECIAL_OWNER)
+			printf("%s", special_owner(p->fmr_owner, owner));
+		else if (p->fmr_flags & FMR_OF_EXTENT_MAP)
+			printf(_("inode %lld extent map"),
+				(long long) p->fmr_owner);
+		else
+			printf(_("inode %lld %lld..%lld"),
+				(long long)p->fmr_owner,
+				(long long)BTOBBT(p->fmr_offset),
+				(long long)BTOBBT(p->fmr_offset + p->fmr_length - 1));
+		printf(_(" %lld blocks\n"),
+			(long long)BTOBBT(p->fmr_length));
+	}
+
+	(*nr) += head->fmh_entries;
+}
+
+/*
+ * Verbose mode displays:
+ *   extent: major:minor [startblock..endblock]: startoffset..endoffset \
+ *	ag# (agoffset..agendoffset) totalbbs flags
+ */
+#define MINRANGE_WIDTH	16
+#define MINAG_WIDTH	2
+#define MINTOT_WIDTH	5
+#define NFLG		7		/* count of flags */
+#define	FLG_NULL	00000000	/* Null flag */
+#define	FLG_ATTR_FORK	01000000	/* attribute fork */
+#define	FLG_SHARED	00100000	/* shared extent */
+#define	FLG_PRE		00010000	/* Unwritten extent */
+#define	FLG_BSU		00001000	/* Not on begin of stripe unit  */
+#define	FLG_ESU		00000100	/* Not on end   of stripe unit  */
+#define	FLG_BSW		00000010	/* Not on begin of stripe width */
+#define	FLG_ESW		00000001	/* Not on end   of stripe width */
+static void
+dump_map_verbose(
+	unsigned long long	*nr,
+	struct fsmap_head	*head,
+	bool			*dumped_flags,
+	struct xfs_fsop_geom	*fsgeo)
+{
+	unsigned long long	i;
+	struct fsmap		*p;
+	int			agno;
+	off64_t			agoff, bperag;
+	int			foff_w, boff_w, aoff_w, tot_w, agno_w, own_w;
+	int			nr_w, dev_w;
+	char			rbuf[32], bbuf[32], abuf[32], obuf[32];
+	char			nbuf[32], dbuf[32], gbuf[32];
+	char			owner[OWNER_BUF_SZ];
+	int			sunit, swidth;
+	int			flg = 0;
+
+	foff_w = boff_w = aoff_w = own_w = MINRANGE_WIDTH;
+	dev_w = 3;
+	nr_w = 4;
+	tot_w = MINTOT_WIDTH;
+	bperag = (off64_t)fsgeo->agblocks *
+		  (off64_t)fsgeo->blocksize;
+	sunit = (fsgeo->sunit * fsgeo->blocksize);
+	swidth = (fsgeo->swidth * fsgeo->blocksize);
+
+	/*
+	 * Go through the extents and figure out the width
+	 * needed for all columns.
+	 */
+	for (i = 0, p = head->fmh_recs; i < head->fmh_entries; i++, p++) {
+		if (p->fmr_flags & FMR_OF_PREALLOC ||
+		    p->fmr_flags & FMR_OF_ATTR_FORK ||
+		    p->fmr_flags & FMR_OF_SHARED)
+			flg = 1;
+		if (sunit &&
+		    (p->fmr_physical  % sunit != 0 ||
+		     ((p->fmr_physical + p->fmr_length) % sunit) != 0 ||
+		     p->fmr_physical % swidth != 0 ||
+		     ((p->fmr_physical + p->fmr_length) % swidth) != 0))
+			flg = 1;
+		if (flg)
+			*dumped_flags = true;
+		snprintf(nbuf, sizeof(nbuf), "%llu", (*nr) + i);
+		nr_w = max(nr_w, strlen(nbuf));
+		if (head->fmh_oflags & FMH_OF_DEV_T)
+			snprintf(dbuf, sizeof(dbuf), "%u:%u",
+				major(p->fmr_device),
+				minor(p->fmr_device));
+		else
+			snprintf(dbuf, sizeof(dbuf), "0x%x", p->fmr_device);
+		dev_w = max(dev_w, strlen(dbuf));
+		snprintf(bbuf, sizeof(bbuf), "[%lld..%lld]:",
+			(long long)BTOBBT(p->fmr_physical),
+			(long long)BTOBBT(p->fmr_physical + p->fmr_length - 1));
+		boff_w = max(boff_w, strlen(bbuf));
+		if (p->fmr_flags & FMR_OF_SPECIAL_OWNER)
+			own_w = max(own_w, strlen(
+					special_owner(p->fmr_owner, owner)));
+		else {
+			snprintf(obuf, sizeof(obuf), "%lld",
+				(long long)p->fmr_owner);
+			own_w = max(own_w, strlen(obuf));
+		}
+		if (p->fmr_flags & FMR_OF_EXTENT_MAP)
+			foff_w = max(foff_w, strlen(_("extent_map")));
+		else if (p->fmr_flags & FMR_OF_SPECIAL_OWNER)
+			;
+		else {
+			snprintf(rbuf, sizeof(rbuf), "%lld..%lld",
+				(long long)BTOBBT(p->fmr_offset),
+				(long long)BTOBBT(p->fmr_offset + p->fmr_length - 1));
+			foff_w = max(foff_w, strlen(rbuf));
+		}
+		if (p->fmr_device == xfs_data_dev) {
+			agno = p->fmr_physical / bperag;
+			agoff = p->fmr_physical - (agno * bperag);
+			snprintf(abuf, sizeof(abuf),
+				"(%lld..%lld)",
+				(long long)BTOBBT(agoff),
+				(long long)BTOBBT(agoff + p->fmr_length - 1));
+		} else
+			abuf[0] = 0;
+		aoff_w = max(aoff_w, strlen(abuf));
+		tot_w = max(tot_w,
+			numlen(BTOBBT(p->fmr_length), 10));
+	}
+	agno_w = max(MINAG_WIDTH, numlen(fsgeo->agcount, 10));
+	if (nr == 0)
+		printf("%*s: %-*s %-*s %-*s %-*s %*s %-*s %*s%s\n",
+			nr_w, _("EXT"),
+			dev_w, _("DEV"),
+			boff_w, _("BLOCK-RANGE"),
+			own_w, _("OWNER"),
+			foff_w, _("FILE-OFFSET"),
+			agno_w, _("AG"),
+			aoff_w, _("AG-OFFSET"),
+			tot_w, _("TOTAL"),
+			flg ? _(" FLAGS") : "");
+	for (i = 0, p = head->fmh_recs; i < head->fmh_entries; i++, p++) {
+		flg = FLG_NULL;
+		if (p->fmr_flags & FMR_OF_PREALLOC)
+			flg |= FLG_PRE;
+		if (p->fmr_flags & FMR_OF_ATTR_FORK)
+			flg |= FLG_ATTR_FORK;
+		if (p->fmr_flags & FMR_OF_SHARED)
+			flg |= FLG_SHARED;
+		/*
+		 * If striping enabled, determine if extent starts/ends
+		 * on a stripe unit boundary.
+		 */
+		if (sunit) {
+			if (p->fmr_physical  % sunit != 0)
+				flg |= FLG_BSU;
+			if (((p->fmr_physical +
+			      p->fmr_length ) % sunit ) != 0)
+				flg |= FLG_ESU;
+			if (p->fmr_physical % swidth != 0)
+				flg |= FLG_BSW;
+			if (((p->fmr_physical +
+			      p->fmr_length ) % swidth ) != 0)
+				flg |= FLG_ESW;
+		}
+		if (head->fmh_oflags & FMH_OF_DEV_T)
+			snprintf(dbuf, sizeof(dbuf), "%u:%u",
+				major(p->fmr_device),
+				minor(p->fmr_device));
+		else
+			snprintf(dbuf, sizeof(dbuf), "0x%x", p->fmr_device);
+		snprintf(bbuf, sizeof(bbuf), "[%lld..%lld]:",
+			(long long)BTOBBT(p->fmr_physical),
+			(long long)BTOBBT(p->fmr_physical + p->fmr_length - 1));
+		if (p->fmr_flags & FMR_OF_SPECIAL_OWNER) {
+			snprintf(obuf, sizeof(obuf), "%s",
+				special_owner(p->fmr_owner, owner));
+			snprintf(rbuf, sizeof(rbuf), " ");
+		} else {
+			snprintf(obuf, sizeof(obuf), "%lld",
+				(long long)p->fmr_owner);
+			snprintf(rbuf, sizeof(rbuf), "%lld..%lld",
+				(long long)BTOBBT(p->fmr_offset),
+				(long long)BTOBBT(p->fmr_offset + p->fmr_length - 1));
+		}
+		if (p->fmr_device == xfs_data_dev) {
+			agno = p->fmr_physical / bperag;
+			agoff = p->fmr_physical - (agno * bperag);
+			snprintf(abuf, sizeof(abuf),
+				"(%lld..%lld)",
+				(long long)BTOBBT(agoff),
+				(long long)BTOBBT(agoff + p->fmr_length - 1));
+			snprintf(gbuf, sizeof(gbuf),
+				"%lld",
+				(long long)agno);
+		} else {
+			abuf[0] = 0;
+			gbuf[0] = 0;
+		}
+		if (p->fmr_flags & FMR_OF_EXTENT_MAP)
+			printf("%*llu: %-*s %-*s %-*s %-*s %-*s %-*s %*lld\n",
+				nr_w, (*nr) + i,
+				dev_w, dbuf,
+				boff_w, bbuf,
+				own_w, obuf,
+				foff_w, _("extent map"),
+				agno_w, gbuf,
+				aoff_w, abuf,
+				tot_w, (long long)BTOBBT(p->fmr_length));
+		else {
+			printf("%*llu: %-*s %-*s %-*s %-*s", nr_w, (*nr) + i,
+				dev_w, dbuf, boff_w, bbuf, own_w, obuf,
+				foff_w, rbuf);
+			printf(" %-*s %-*s", agno_w, gbuf,
+				aoff_w, abuf);
+			printf(" %*lld", tot_w,
+				(long long)BTOBBT(p->fmr_length));
+			if (flg == FLG_NULL)
+				printf("\n");
+			else
+				printf(" %-*.*o\n", NFLG, NFLG, flg);
+		}
+	}
+
+	(*nr) += head->fmh_entries;
+}
+
+static void
+dump_verbose_key(void)
+{
+	printf(_(" FLAG Values:\n"));
+	printf(_("    %*.*o Attribute fork\n"),
+		NFLG+1, NFLG+1, FLG_ATTR_FORK);
+	printf(_("    %*.*o Shared extent\n"),
+		NFLG+1, NFLG+1, FLG_SHARED);
+	printf(_("    %*.*o Unwritten preallocated extent\n"),
+		NFLG+1, NFLG+1, FLG_PRE);
+	printf(_("    %*.*o Doesn't begin on stripe unit\n"),
+		NFLG+1, NFLG+1, FLG_BSU);
+	printf(_("    %*.*o Doesn't end   on stripe unit\n"),
+		NFLG+1, NFLG+1, FLG_ESU);
+	printf(_("    %*.*o Doesn't begin on stripe width\n"),
+		NFLG+1, NFLG+1, FLG_BSW);
+	printf(_("    %*.*o Doesn't end   on stripe width\n"),
+		NFLG+1, NFLG+1, FLG_ESW);
+}
+
+int
+fsmap_f(
+	int			argc,
+	char			**argv)
+{
+	struct fsmap		*p;
+	struct fsmap_head	*nhead;
+	struct fsmap_head	*head;
+	struct fsmap		*l, *h;
+	struct xfs_fsop_geom	fsgeo;
+	long long		start = 0;
+	long long		end = -1;
+	int			nmap_size;
+	int			map_size;
+	int			nflag = 0;
+	int			vflag = 0;
+	int			i = 0;
+	int			c;
+	unsigned long long	nr = 0;
+	size_t			fsblocksize, fssectsize;
+	struct fs_path		*fs;
+	static bool		tab_init;
+	bool			dumped_flags = false;
+	int			dflag, lflag, rflag;
+
+	init_cvtnum(&fsblocksize, &fssectsize);
+
+	dflag = lflag = rflag = 0;
+	while ((c = getopt(argc, argv, "dln:rv")) != EOF) {
+		switch (c) {
+		case 'd':	/* data device */
+			dflag = 1;
+			break;
+		case 'l':	/* log device */
+			lflag = 1;
+			break;
+		case 'n':	/* number of extents specified */
+			nflag = atoi(optarg);
+			break;
+		case 'r':	/* rt device */
+			rflag = 1;
+			break;
+		case 'v':	/* Verbose output */
+			vflag++;
+			break;
+		default:
+			return command_usage(&fsmap_cmd);
+		}
+	}
+
+	if (dflag + lflag + rflag > 1)
+		return command_usage(&fsmap_cmd);
+
+	if (argc > optind && dflag + lflag + rflag == 0)
+		return command_usage(&fsmap_cmd);
+
+	if (argc > optind) {
+		start = cvtnum(fsblocksize, fssectsize, argv[optind]);
+		if (start < 0) {
+			fprintf(stderr,
+				_("Bad rmap start_bblock %s.\n"),
+				argv[optind]);
+			return 0;
+		}
+		start <<= BBSHIFT;
+	}
+
+	if (argc > optind + 1) {
+		end = cvtnum(fsblocksize, fssectsize, argv[optind + 1]);
+		if (end < 0) {
+			fprintf(stderr,
+				_("Bad rmap end_bblock %s.\n"),
+				argv[optind + 1]);
+			return 0;
+		}
+		end <<= BBSHIFT;
+	}
+
+	if (vflag) {
+		c = ioctl(file->fd, XFS_IOC_FSGEOMETRY, &fsgeo);
+		if (c < 0) {
+			fprintf(stderr,
+				_("%s: can't get geometry [\"%s\"]: %s\n"),
+				progname, file->name, strerror(errno));
+			exitcode = 1;
+			return 0;
+		}
+	}
+
+	map_size = nflag ? nflag : 131072 / sizeof(struct fsmap);
+	head = malloc(fsmap_sizeof(map_size));
+	if (head == NULL) {
+		fprintf(stderr, _("%s: malloc of %zu bytes failed.\n"),
+			progname, fsmap_sizeof(map_size));
+		exitcode = 1;
+		return 0;
+	}
+
+	memset(head, 0, sizeof(*head));
+	l = head->fmh_keys;
+	h = head->fmh_keys + 1;
+	if (dflag) {
+		l->fmr_device = h->fmr_device = file->fs_path.fs_datadev;
+	} else if (lflag) {
+		l->fmr_device = h->fmr_device = file->fs_path.fs_logdev;
+	} else if (rflag) {
+		l->fmr_device = h->fmr_device = file->fs_path.fs_rtdev;
+	} else {
+		l->fmr_device = 0;
+		h->fmr_device = UINT_MAX;
+	}
+	l->fmr_physical = start;
+	h->fmr_physical = end;
+	h->fmr_owner = ULLONG_MAX;
+	h->fmr_flags = UINT_MAX;
+	h->fmr_offset = ULLONG_MAX;
+
+	/* Count mappings */
+	if (!nflag) {
+		head->fmh_count = 0;
+		i = ioctl(file->fd, FS_IOC_GETFSMAP, head);
+		if (i < 0) {
+			fprintf(stderr, _("%s: xfsctl(XFS_IOC_GETFSMAP)"
+				" iflags=0x%x [\"%s\"]: %s\n"),
+				progname, head->fmh_iflags, file->name,
+				strerror(errno));
+			free(head);
+			exitcode = 1;
+			return 0;
+		}
+		if (head->fmh_entries > map_size + 2) {
+			map_size = 11ULL * head->fmh_entries / 10;
+			nmap_size = map_size > (1 << 24) ? (1 << 24) : map_size;
+			nhead = realloc(head, fsmap_sizeof(nmap_size));
+			if (nhead == NULL) {
+				fprintf(stderr,
+					_("%s: cannot realloc %zu bytes\n"),
+					progname, fsmap_sizeof(nmap_size));
+			} else {
+				head = nhead;
+				map_size = nmap_size;
+			}
+		}
+	}
+
+	/*
+	 * If this is an XFS filesystem, remember the data device.
+	 * (We report AG number/block for data device extents on XFS).
+	 */
+	if (!tab_init) {
+		fs_table_initialise(0, NULL, 0, NULL);
+		tab_init = true;
+	}
+	fs = fs_table_lookup(file->name, FS_MOUNT_POINT);
+	xfs_data_dev = fs ? fs->fs_datadev : 0;
+
+	head->fmh_count = map_size;
+	do {
+		/* Get some extents */
+		i = ioctl(file->fd, FS_IOC_GETFSMAP, head);
+		if (i < 0) {
+			fprintf(stderr, _("%s: xfsctl(XFS_IOC_GETFSMAP)"
+				" iflags=0x%x [\"%s\"]: %s\n"),
+				progname, head->fmh_iflags, file->name,
+				strerror(errno));
+			free(head);
+			exitcode = 1;
+			return 0;
+		}
+
+		if (head->fmh_entries == 0)
+			break;
+
+		if (!vflag)
+			dump_map(&nr, head);
+		else
+			dump_map_verbose(&nr, head, &dumped_flags, &fsgeo);
+
+		p = &head->fmh_recs[head->fmh_entries - 1];
+		if (p->fmr_flags & FMR_OF_LAST)
+			break;
+		fsmap_advance(head);
+	} while (true);
+
+	if (dumped_flags)
+		dump_verbose_key();
+
+	free(head);
+	return 0;
+}
+
+void
+fsmap_init(void)
+{
+	fsmap_cmd.name = "fsmap";
+	fsmap_cmd.cfunc = fsmap_f;
+	fsmap_cmd.argmin = 0;
+	fsmap_cmd.argmax = -1;
+	fsmap_cmd.flags = CMD_NOMAP_OK | CMD_FLAG_FOREIGN_OK;
+	fsmap_cmd.args = _("[-d|-l|-r] [-v] [-n nx] [start] [end]");
+	fsmap_cmd.oneline = _("print filesystem mapping for a range of blocks");
+	fsmap_cmd.help = fsmap_help;
+
+	add_command(&fsmap_cmd);
+}
diff --git a/io/init.c b/io/init.c
index c15a1e1..20d5f80 100644
--- a/io/init.c
+++ b/io/init.c
@@ -66,6 +66,7 @@  init_commands(void)
 	file_init();
 	flink_init();
 	freeze_init();
+	fsmap_init();
 	fsync_init();
 	getrusage_init();
 	help_init();
@@ -139,6 +140,7 @@  init(
 	char		*sp;
 	mode_t		mode = 0600;
 	xfs_fsop_geom_t	geometry = { 0 };
+	struct fs_path	fsp;
 
 	progname = basename(argv[0]);
 	setlocale(LC_ALL, "");
@@ -148,6 +150,7 @@  init(
 	pagesize = getpagesize();
 	gettimeofday(&stopwatch, NULL);
 
+	fs_table_initialise(0, NULL, 0, NULL);
 	while ((c = getopt(argc, argv, "ac:C:dFfim:p:nrRstTVx")) != EOF) {
 		switch (c) {
 		case 'a':
@@ -212,11 +215,12 @@  init(
 	}
 
 	while (optind < argc) {
-		if ((c = openfile(argv[optind], &geometry, flags, mode)) < 0)
+		c = openfile(argv[optind], &geometry, flags, mode, &fsp);
+		if (c < 0)
 			exit(1);
 		if (!platform_test_xfs_fd(c))
 			flags |= IO_FOREIGN;
-		if (addfile(argv[optind], c, &geometry, flags) < 0)
+		if (addfile(argv[optind], c, &geometry, flags, &fsp) < 0)
 			exit(1);
 		optind++;
 	}
diff --git a/io/io.h b/io/io.h
index 952bdb8..6a0fe65 100644
--- a/io/io.h
+++ b/io/io.h
@@ -17,6 +17,7 @@ 
  */
 
 #include "xfs.h"
+#include "path.h"
 
 /*
  * Read/write patterns (default is always "forward")
@@ -47,6 +48,7 @@  typedef struct fileio {
 	int		flags;		/* flags describing file state */
 	char		*name;		/* file name at time of open */
 	xfs_fsop_geom_t	geom;		/* XFS filesystem geometry */
+	struct fs_path	fs_path;	/* XFS path information */
 } fileio_t;
 
 extern fileio_t		*filetable;	/* open file table */
@@ -76,8 +78,10 @@  extern void *check_mapping_range(mmap_region_t *, off64_t, size_t, int);
  */
 
 extern off64_t		filesize(void);
-extern int		openfile(char *, xfs_fsop_geom_t *, int, mode_t);
-extern int		addfile(char *, int , xfs_fsop_geom_t *, int);
+extern int		openfile(char *, xfs_fsop_geom_t *, int, mode_t,
+				 struct fs_path *);
+extern int		addfile(char *, int , xfs_fsop_geom_t *, int,
+				struct fs_path *);
 extern void		printxattr(uint, int, int, const char *, int, int);
 
 extern unsigned int	recurse_all;
@@ -174,3 +178,9 @@  extern void		readdir_init(void);
 extern void		reflink_init(void);
 
 extern void		cowextsize_init(void);
+
+#ifdef HAVE_GETFSMAP
+extern void		fsmap_init(void);
+#else
+# define fsmap_init()	do { } while (0)
+#endif
diff --git a/io/open.c b/io/open.c
index 2ed55cf..b50f068 100644
--- a/io/open.c
+++ b/io/open.c
@@ -52,8 +52,10 @@  openfile(
 	char		*path,
 	xfs_fsop_geom_t	*geom,
 	int		flags,
-	mode_t		mode)
+	mode_t		mode,
+	struct fs_path	*fs_path)
 {
+	struct fs_path	*fsp;
 	int		fd;
 	int		oflags;
 
@@ -118,6 +120,14 @@  openfile(
 			}
 		}
 	}
+
+	if (fs_path) {
+		fsp = fs_table_lookup(path, FS_MOUNT_POINT);
+		if (!fsp)
+			memset(fs_path, 0, sizeof(*fs_path));
+		else
+			*fs_path = *fsp;
+	}
 	return fd;
 }
 
@@ -126,7 +136,8 @@  addfile(
 	char		*name,
 	int		fd,
 	xfs_fsop_geom_t	*geometry,
-	int		flags)
+	int		flags,
+	struct fs_path	*fs_path)
 {
 	char		*filename;
 
@@ -154,6 +165,7 @@  addfile(
 	file->flags = flags;
 	file->name = filename;
 	file->geom = *geometry;
+	file->fs_path = *fs_path;
 	return 0;
 }
 
@@ -195,6 +207,7 @@  open_f(
 	char		*sp;
 	mode_t		mode = 0600;
 	xfs_fsop_geom_t	geometry = { 0 };
+	struct fs_path	fsp;
 
 	if (argc == 1) {
 		if (file)
@@ -257,14 +270,14 @@  open_f(
 		return -1;
 	}
 
-	fd = openfile(argv[optind], &geometry, flags, mode);
+	fd = openfile(argv[optind], &geometry, flags, mode, &fsp);
 	if (fd < 0)
 		return 0;
 
 	if (!platform_test_xfs_fd(fd))
 		flags |= IO_FOREIGN;
 
-	addfile(argv[optind], fd, &geometry, flags);
+	addfile(argv[optind], fd, &geometry, flags, &fsp);
 	return 0;
 }
 
diff --git a/io/pwrite.c b/io/pwrite.c
index 7c0bb7f..1c5dfca 100644
--- a/io/pwrite.c
+++ b/io/pwrite.c
@@ -357,7 +357,7 @@  pwrite_f(
 		return 0;
 
 	c = IO_READONLY | (dflag ? IO_DIRECT : 0);
-	if (infile && ((fd = openfile(infile, NULL, c, 0)) < 0))
+	if (infile && ((fd = openfile(infile, NULL, c, 0, NULL)) < 0))
 		return 0;
 
 	gettimeofday(&t1, NULL);
diff --git a/io/reflink.c b/io/reflink.c
index fe05d1e..f584e8f 100644
--- a/io/reflink.c
+++ b/io/reflink.c
@@ -154,7 +154,7 @@  dedupe_f(
 		return 0;
 	}
 
-	fd = openfile(infile, NULL, IO_READONLY, 0);
+	fd = openfile(infile, NULL, IO_READONLY, 0, NULL);
 	if (fd < 0)
 		return 0;
 
@@ -278,7 +278,7 @@  reflink_f(
 	}
 
 clone_all:
-	fd = openfile(infile, NULL, IO_READONLY, 0);
+	fd = openfile(infile, NULL, IO_READONLY, 0, NULL);
 	if (fd < 0)
 		return 0;
 
diff --git a/io/sendfile.c b/io/sendfile.c
index edd31c9..063fa7f 100644
--- a/io/sendfile.c
+++ b/io/sendfile.c
@@ -115,7 +115,7 @@  sendfile_f(
 
 	if (!infile)
 		fd = filetable[fd].fd;
-	else if ((fd = openfile(infile, NULL, IO_READONLY, 0)) < 0)
+	else if ((fd = openfile(infile, NULL, IO_READONLY, 0, NULL)) < 0)
 		return 0;
 
 	if (optind == argc - 2) {
diff --git a/man/man8/xfs_io.8 b/man/man8/xfs_io.8
index 29a036c..bd8af47 100644
--- a/man/man8/xfs_io.8
+++ b/man/man8/xfs_io.8
@@ -301,6 +301,72 @@  ioctl.  Options behave as described in the
 .BR xfs_bmap (8)
 manual page.
 .TP
+.BI "fsmap [ \-d | \-l | \-r ] [ \-v ] [ \-n " nx " ] [ " start " ] [ " end " ]
+Prints the mapping of disk blocks used by a filesystem.
+The map lists each extent used by files, allocation group metadata,
+journalling logs, and static filesystem metadata, as well as any
+regions that are unused.
+Each line of the listings takes the following form:
+.PP
+.RS
+.IR extent ": " major ":" minor " [" startblock .. endblock "]: " owner " " startoffset .. endoffset " " length
+.PP
+Static filesystem metadata, allocation group metadata, btrees,
+journalling logs, and free space are marked by replacing the
+.IR startoffset .. endoffset
+with the appropriate marker.
+All blocks, offsets, and lengths are specified in units of 512-byte
+blocks, no matter what the filesystem's block size is.
+The optional
+.I start
+and
+.I end
+arguments can be used to constrain the output to a particular range of
+disk blocks.
+.RE
+.RS 1.0i
+.PD 0
+.TP
+.BI \-d
+Display only extents from the data device.
+This option only applies for XFS filesystems.
+.TP
+.BI \-l
+Display only extents from the external log device.
+This option only applies to XFS filesystems.
+.TP
+.BI \-r
+Display only extents from the realtime device.
+This option only applies to XFS filesystems.
+.TP
+.BI \-n " num_extents"
+If this option is given,
+.B xfs_fsmap
+obtains the extent list of the file in groups of
+.I num_extents
+extents.
+In the absence of
+.BR \-n ", " xfs_fsmap
+queries the system for the number of extents in the filesystem and uses
+that value to compute the group size.
+.TP
+.B \-v
+Shows verbose information.
+When this flag is specified, additional AG specific information is
+appended to each line in the following form:
+.IP
+.RS 1.2i
+.IR agno " (" startagblock .. endagblock ") " nblocks " " flags
+.RE
+.IP
+A second
+.B \-v
+option will print out the
+.I flags
+legend.
+.RE
+.PD
+.TP
 .BI "extsize [ \-R | \-D ] [ " value " ]"
 Display and/or modify the preferred extent size used when allocating
 space for the currently open file. If the