Re: [PATCH 1/2] xfs_db: dump unlinked buckets

[Bill O'Donnell <bodonnel@redhat.com>]

On Wed, Aug 30, 2023 at 04:25:09PM -0700, Darrick J. Wong wrote:
> From: Darrick J. Wong <djwong@kernel.org>
> 
> Create a new command to dump the resource usage of files in the unlinked
> buckets.
> 
> Signed-off-by: Darrick J. Wong <djwong@kernel.org>

Reviewed-by: Bill O'Donnell <bodonnel@redhat.com>

> ---
>  db/Makefile              |    2 
>  db/command.c             |    1 
>  db/command.h             |    1 
>  db/iunlink.c             |  204 ++++++++++++++++++++++++++++++++++++++++++++++
>  libxfs/libxfs_api_defs.h |    1 
>  man/man8/xfs_db.8        |   19 ++++
>  6 files changed, 227 insertions(+), 1 deletion(-)
>  create mode 100644 db/iunlink.c
> 
> diff --git a/db/Makefile b/db/Makefile
> index 2f95f670..d00801ab 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 obfuscate.h
> -CFILES = $(HFILES:.h=.c) btdump.c btheight.c convert.c info.c namei.c \
> +CFILES = $(HFILES:.h=.c) btdump.c btheight.c convert.c info.c iunlink.c namei.c \
>  	timelimit.c
>  LSRCFILES = xfs_admin.sh xfs_ncheck.sh xfs_metadump.sh
>  
> diff --git a/db/command.c b/db/command.c
> index 02f778b9..b4021c86 100644
> --- a/db/command.c
> +++ b/db/command.c
> @@ -127,6 +127,7 @@ init_commands(void)
>  	info_init();
>  	inode_init();
>  	input_init();
> +	iunlink_init();
>  	logres_init();
>  	logformat_init();
>  	io_init();
> diff --git a/db/command.h b/db/command.h
> index 498983ff..a89e7150 100644
> --- a/db/command.h
> +++ b/db/command.h
> @@ -34,3 +34,4 @@ extern void		info_init(void);
>  extern void		btheight_init(void);
>  extern void		timelimit_init(void);
>  extern void		namei_init(void);
> +extern void		iunlink_init(void);
> diff --git a/db/iunlink.c b/db/iunlink.c
> new file mode 100644
> index 00000000..303b5daf
> --- /dev/null
> +++ b/db/iunlink.c
> @@ -0,0 +1,204 @@
> +// SPDX-License-Identifier: GPL-2.0
> +/*
> + * Copyright (C) 2022-2023 Oracle.  All Rights Reserved.
> + * Author: Darrick J. Wong <djwong@kernel.org>
> + */
> +#include "libxfs.h"
> +#include "command.h"
> +#include "output.h"
> +#include "init.h"
> +
> +static xfs_filblks_t
> +count_rtblocks(
> +	struct xfs_inode	*ip)
> +{
> +	struct xfs_iext_cursor	icur;
> +	struct xfs_bmbt_irec	got;
> +	xfs_filblks_t		count = 0;
> +	struct xfs_ifork	*ifp = xfs_ifork_ptr(ip, XFS_DATA_FORK);
> +	int			error;
> +
> +	error = -libxfs_iread_extents(NULL, ip, XFS_DATA_FORK);
> +	if (error) {
> +		dbprintf(
> +_("could not read AG %u agino %u extents, err=%d\n"),
> +				XFS_INO_TO_AGNO(ip->i_mount, ip->i_ino),
> +				XFS_INO_TO_AGINO(ip->i_mount, ip->i_ino),
> +				error);
> +		return 0;
> +	}
> +
> +	for_each_xfs_iext(ifp, &icur, &got)
> +		if (!isnullstartblock(got.br_startblock))
> +			count += got.br_blockcount;
> +	return count;
> +}
> +
> +static xfs_agino_t
> +get_next_unlinked(
> +	xfs_agnumber_t		agno,
> +	xfs_agino_t		agino,
> +	bool			verbose)
> +{
> +	struct xfs_buf		*ino_bp;
> +	struct xfs_dinode	*dip;
> +	struct xfs_inode	*ip;
> +	xfs_ino_t		ino;
> +	xfs_agino_t		ret;
> +	int			error;
> +
> +	ino = XFS_AGINO_TO_INO(mp, agno, agino);
> +	error = -libxfs_iget(mp, NULL, ino, 0, &ip);
> +	if (error)
> +		goto bad;
> +
> +	if (verbose) {
> +		xfs_filblks_t	blocks, rtblks = 0;
> +
> +		if (XFS_IS_REALTIME_INODE(ip))
> +			rtblks = count_rtblocks(ip);
> +		blocks = ip->i_nblocks - rtblks;
> +
> +		dbprintf(_(" blocks %llu rtblocks %llu\n"),
> +				blocks, rtblks);
> +	} else {
> +		dbprintf("\n");
> +	}
> +
> +	error = -libxfs_imap_to_bp(mp, NULL, &ip->i_imap, &ino_bp);
> +	if (error)
> +		goto bad;
> +
> +	dip = xfs_buf_offset(ino_bp, ip->i_imap.im_boffset);
> +	ret = be32_to_cpu(dip->di_next_unlinked);
> +	libxfs_buf_relse(ino_bp);
> +
> +	return ret;
> +bad:
> +	dbprintf(_("AG %u agino %u: %s\n"), agno, agino, strerror(error));
> +	return NULLAGINO;
> +}
> +
> +static void
> +dump_unlinked_bucket(
> +	xfs_agnumber_t	agno,
> +	struct xfs_buf	*agi_bp,
> +	unsigned int	bucket,
> +	bool		quiet,
> +	bool		verbose)
> +{
> +	struct xfs_agi	*agi = agi_bp->b_addr;
> +	xfs_agino_t	agino;
> +	unsigned int	i = 0;
> +
> +	agino = be32_to_cpu(agi->agi_unlinked[bucket]);
> +	if (agino != NULLAGINO)
> +		dbprintf(_("AG %u bucket %u agino %u"), agno, bucket, agino);
> +	else if (!quiet && agino == NULLAGINO)
> +		dbprintf(_("AG %u bucket %u agino NULL\n"), agno, bucket);
> +
> +	while (agino != NULLAGINO) {
> +		agino = get_next_unlinked(agno, agino, verbose);
> +		if (agino != NULLAGINO)
> +			dbprintf(_("    [%u] agino %u"), i++, agino);
> +		else if (!quiet && agino == NULLAGINO)
> +			dbprintf(_("    [%u] agino NULL\n"), i++);
> +	}
> +}
> +
> +static void
> +dump_unlinked(
> +	struct xfs_perag	*pag,
> +	unsigned int		bucket,
> +	bool			quiet,
> +	bool			verbose)
> +{
> +	struct xfs_buf		*agi_bp;
> +	xfs_agnumber_t		agno = pag->pag_agno;
> +	int			error;
> +
> +	error = -libxfs_ialloc_read_agi(pag, NULL, &agi_bp);
> +	if (error) {
> +		dbprintf(_("AGI %u: %s\n"), agno, strerror(errno));
> +		return;
> +	}
> +
> +	if (bucket != -1U) {
> +		dump_unlinked_bucket(agno, agi_bp, bucket, quiet, verbose);
> +		goto relse;
> +	}
> +
> +	for (bucket = 0; bucket < XFS_AGI_UNLINKED_BUCKETS; bucket++) {
> +		dump_unlinked_bucket(agno, agi_bp, bucket, quiet, verbose);
> +	}
> +
> +relse:
> +	libxfs_buf_relse(agi_bp);
> +}
> +
> +static int
> +dump_iunlinked_f(
> +	int			argc,
> +	char			**argv)
> +{
> +	struct xfs_perag	*pag;
> +	xfs_agnumber_t		agno = NULLAGNUMBER;
> +	unsigned int		bucket = -1U;
> +	bool			quiet = false;
> +	bool			verbose = false;
> +	int			c;
> +
> +	while ((c = getopt(argc, argv, "a:b:qv")) != EOF) {
> +		switch (c) {
> +		case 'a':
> +			agno = atoi(optarg);
> +			if (agno >= mp->m_sb.sb_agcount) {
> +				dbprintf(_("Unknown AG %u, agcount is %u.\n"),
> +						agno, mp->m_sb.sb_agcount);
> +				return 0;
> +			}
> +			break;
> +		case 'b':
> +			bucket = atoi(optarg);
> +			if (bucket >= XFS_AGI_UNLINKED_BUCKETS) {
> +				dbprintf(_("Unknown bucket %u, max is 63.\n"),
> +						bucket);
> +				return 0;
> +			}
> +			break;
> +		case 'q':
> +			quiet = true;
> +			break;
> +		case 'v':
> +			verbose = true;
> +			break;
> +		default:
> +			dbprintf(_("Bad option for dump_iunlinked command.\n"));
> +			return 0;
> +		}
> +	}
> +
> +	if (agno != NULLAGNUMBER) {
> +		struct xfs_perag	*pag = libxfs_perag_get(mp, agno);
> +
> +		dump_unlinked(pag, bucket, quiet, verbose);
> +		libxfs_perag_put(pag);
> +		return 0;
> +	}
> +
> +	for_each_perag(mp, agno, pag)
> +		dump_unlinked(pag, bucket, quiet, verbose);
> +
> +	return 0;
> +}
> +
> +static const cmdinfo_t	dump_iunlinked_cmd =
> +	{ "dump_iunlinked", NULL, dump_iunlinked_f, 0, -1, 0,
> +	  N_("[-a agno] [-b bucket] [-q] [-v]"),
> +	  N_("dump chain of unlinked inode buckets"), NULL };
> +
> +void
> +iunlink_init(void)
> +{
> +	add_command(&dump_iunlinked_cmd);
> +}
> diff --git a/libxfs/libxfs_api_defs.h b/libxfs/libxfs_api_defs.h
> index 026aa510..ddba5c7c 100644
> --- a/libxfs/libxfs_api_defs.h
> +++ b/libxfs/libxfs_api_defs.h
> @@ -125,6 +125,7 @@
>  #define xfs_idestroy_fork		libxfs_idestroy_fork
>  #define xfs_iext_lookup_extent		libxfs_iext_lookup_extent
>  #define xfs_ifork_zap_attr		libxfs_ifork_zap_attr
> +#define xfs_imap_to_bp			libxfs_imap_to_bp
>  #define xfs_initialize_perag		libxfs_initialize_perag
>  #define xfs_initialize_perag_data	libxfs_initialize_perag_data
>  #define xfs_init_local_fork		libxfs_init_local_fork
> diff --git a/man/man8/xfs_db.8 b/man/man8/xfs_db.8
> index 60dcdc52..2d6d0da4 100644
> --- a/man/man8/xfs_db.8
> +++ b/man/man8/xfs_db.8
> @@ -579,6 +579,25 @@ print the current debug option bits. These are for the use of the implementor.
>  .BI "dquot [" \-g | \-p | \-u ] " id"
>  Set current address to a group, project or user quota block for the given ID. Defaults to user quota.
>  .TP
> +.BI "dump_iunlinked [-a " agno " ] [-b " bucket " ] [-q] [-v]"
> +Dump the contents of unlinked buckets.
> +
> +Options include:
> +.RS 1.0i
> +.TP 0.4i
> +.B \-a
> +Print only this AG's unlinked buckets.
> +.TP 0.4i
> +.B \-b
> +Print only this bucket within each AGI.
> +.TP 0.4i
> +.B \-q
> +Only print the essentials.
> +.TP 0.4i
> +.B \-v
> +Print resource usage of each file on the unlinked lists.
> +.RE
> +.TP
>  .BI "echo [" arg "] ..."
>  Echo the arguments to the output.
>  .TP
>