Re: [PATCH 24/27] xfs_scrub: fstrim the free areas if there are no errors on the filesystem

["Darrick J. Wong" <darrick.wong@oracle.com>]

On Tue, Jan 16, 2018 at 04:07:44PM -0600, Eric Sandeen wrote:
> On 1/5/18 7:54 PM, Darrick J. Wong wrote:
> > From: Darrick J. Wong <darrick.wong@oracle.com>
> > 
> > If the filesystem scan comes out clean or fixes all the problems, call
> > fstrim to clean out the free areas (if it's an ssd/thinp/whatever).
> 
> Is this the right patch header for this patch?
> 
> Oh ok, this adds a "repair phase" which is really only implementing
> preen for now, which is really only fstrimming at this point.
> 
> so:
> 
> preen()
>   if no errors
>      xfs_repair_fs() (IMHO odd to call "repair" on a clean filesystem?)
>        fstrim
> 
> So I guess what was confusing to me is that you do "preen" work under
> "repair" functions.  I get it that they might all be lumped together
> in pending work now, but I'm still wrapping my head around what does
> and doesn't happen in various modes, and how to recognize that in
> the code...

Based on our extended IRC conversations I was planning to rename the
"repair list" to "action items" so that we could have a
xfs_process_action_items() that actually takes care of issuing the
repair calls, then we could have two wrappers:

xfs_repair_fs() -> xfs_process_action_items(); fstrim();
xfs_preen_fs() -> if (!ctx->errors_found) xfs_process_action_items()

> 
> 
> > Signed-off-by: Darrick J. Wong <darrick.wong@oracle.com>
> > ---
> >  scrub/Makefile    |    1 +
> >  scrub/phase4.c    |   52 ++++++++++++++++++++++++++++++++++++++++++++++++++++
> >  scrub/vfs.c       |   23 +++++++++++++++++++++++
> >  scrub/vfs.h       |    2 ++
> >  scrub/xfs_scrub.c |   26 +++++++++++++++++++++++++-
> >  scrub/xfs_scrub.h |    1 +
> >  6 files changed, 104 insertions(+), 1 deletion(-)
> >  create mode 100644 scrub/phase4.c
> > 
> > 
> > diff --git a/scrub/Makefile b/scrub/Makefile
> > index fd26624..91f99ff 100644
> > --- a/scrub/Makefile
> > +++ b/scrub/Makefile
> > @@ -41,6 +41,7 @@ inodes.c \
> >  phase1.c \
> >  phase2.c \
> >  phase3.c \
> > +phase4.c \
> >  phase5.c \
> >  phase6.c \
> >  phase7.c \
> > diff --git a/scrub/phase4.c b/scrub/phase4.c
> > new file mode 100644
> > index 0000000..dadf4de
> > --- /dev/null
> > +++ b/scrub/phase4.c
> > @@ -0,0 +1,52 @@
> > +/*
> > + * Copyright (C) 2018 Oracle.  All Rights Reserved.
> > + *
> > + * Author: Darrick J. Wong <darrick.wong@oracle.com>
> > + *
> > + * 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 <stdio.h>
> > +#include <stdint.h>
> > +#include <stdbool.h>
> > +#include <dirent.h>
> > +#include <sys/types.h>
> > +#include <sys/stat.h>
> > +#include <sys/statvfs.h>
> > +#include "xfs.h"
> > +#include "xfs_fs.h"
> > +#include "list.h"
> > +#include "path.h"
> > +#include "workqueue.h"
> > +#include "xfs_scrub.h"
> > +#include "common.h"
> > +#include "scrub.h"
> > +#include "vfs.h"
> > +
> > +/* Phase 4: Repair filesystem. */
> > +
> > +/* Fix everything that needs fixing. */
> > +bool
> > +xfs_repair_fs(
> > +	struct scrub_ctx		*ctx)
> > +{
> > +	bool				moveon = true;
> > +
> > +	pthread_mutex_lock(&ctx->lock);
> > +	if (moveon && ctx->errors_found == 0)
> > +		fstrim(ctx);
> > +	pthread_mutex_unlock(&ctx->lock);
> > +
> > +	return moveon;
> > +}
> > diff --git a/scrub/vfs.c b/scrub/vfs.c
> > index 6a51090..98d356f 100644
> > --- a/scrub/vfs.c
> > +++ b/scrub/vfs.c
> > @@ -219,3 +219,26 @@ _("Could not queue directory scan work."));
> >  	free(sftd);
> >  	return false;
> >  }
> > +
> > +#ifndef FITRIM
> > +struct fstrim_range {
> > +	__u64 start;
> > +	__u64 len;
> > +	__u64 minlen;
> > +};
> > +#define FITRIM		_IOWR('X', 121, struct fstrim_range)	/* Trim */
> > +#endif
> 
> (I wonder if we should move all these "if it ain't available define it"
> stuff into a single header file at some point...)

Yeah, probably....

> > +
> > +/* Call FITRIM to trim all the unused space in a filesystem. */
> > +void
> > +fstrim(
> > +	struct scrub_ctx	*ctx)
> > +{
> > +	struct fstrim_range	range = {0};
> > +	int			error;
> > +
> > +	range.len = ULLONG_MAX;
> > +	error = ioctl(ctx->mnt_fd, FITRIM, &range);
> > +	if (error && errno != EOPNOTSUPP && errno != ENOTTY)
> > +		perror(_("fstrim"));
> > +}
> 
> still wondering if we should have an option to skip this, given some device's
> horrific performance under fstrim, and/or an other desire to keep an image
> whole.

I already added it in my dev tree.  -k turns off FITRIM.

> > diff --git a/scrub/vfs.h b/scrub/vfs.h
> > index 100eb18..3305159 100644
> > --- a/scrub/vfs.h
> > +++ b/scrub/vfs.h
> > @@ -28,4 +28,6 @@ typedef bool (*scan_fs_tree_dirent_fn)(struct scrub_ctx *, const char *,
> >  bool scan_fs_tree(struct scrub_ctx *ctx, scan_fs_tree_dir_fn dir_fn,
> >  		scan_fs_tree_dirent_fn dirent_fn, void *arg);
> >  
> > +void fstrim(struct scrub_ctx *ctx);
> > +
> >  #endif /* XFS_SCRUB_VFS_H_ */
> > diff --git a/scrub/xfs_scrub.c b/scrub/xfs_scrub.c
> > index bc40f3c..7809431 100644
> > --- a/scrub/xfs_scrub.c
> > +++ b/scrub/xfs_scrub.c
> > @@ -340,6 +340,20 @@ _("%sI/O rate: %.1f%s/s in, %.1f%s/s out, %.1f%s/s tot\n"),
> >  	return true;
> >  }
> >  
> > +/* Run the preening phase if there are no errors. */
> > +static bool
> > +preen(
> > +	struct scrub_ctx	*ctx)
> > +{
> > +	if (ctx->errors_found) {
> > +		str_info(ctx, ctx->mntpoint,
> > +_("Errors found, please re-run with -y."));
> > +		return true;
> > +	}
> > +
> > +	return xfs_repair_fs(ctx);
> > +}
> > +
> >  /* Run all the phases of the scrubber. */
> >  static bool
> >  run_scrub_phases(
> > @@ -393,8 +407,18 @@ run_scrub_phases(
> >  	/* Run all phases of the scrub tool. */
> >  	for (phase = 1, sp = phases; sp->fn; sp++, phase++) {
> >  		/* Turn on certain phases if user said to. */
> > -		if (sp->fn == DATASCAN_DUMMY_FN && scrub_data)
> > +		if (sp->fn == DATASCAN_DUMMY_FN && scrub_data) {
> >  			sp->fn = xfs_scan_blocks;
> > +		} else if (sp->fn == REPAIR_DUMMY_FN) {
> > +			if (ctx->mode == SCRUB_MODE_PREEN) {
> > +				sp->descr = _("Preen filesystem.");
> > +				sp->fn = preen;
> > +			} else if (ctx->mode == SCRUB_MODE_REPAIR) {
> > +				sp->descr = _("Repair filesystem.");
> > +				sp->fn = xfs_repair_fs;
> > +			}
> > +			sp->must_run = true;
> 
> if must_run is always true here, should it just be initialized in
> the structure along w/ the other must_run phases?

Ok.

--D

> > +		}
> >  
> >  		/* Skip certain phases unless they're turned on. */
> >  		if (sp->fn == REPAIR_DUMMY_FN ||
> > diff --git a/scrub/xfs_scrub.h b/scrub/xfs_scrub.h
> > index a5cdba8..4a383f1 100644
> > --- a/scrub/xfs_scrub.h
> > +++ b/scrub/xfs_scrub.h
> > @@ -108,5 +108,6 @@ bool xfs_scan_inodes(struct scrub_ctx *ctx);
> >  bool xfs_scan_connections(struct scrub_ctx *ctx);
> >  bool xfs_scan_blocks(struct scrub_ctx *ctx);
> >  bool xfs_scan_summary(struct scrub_ctx *ctx);
> > +bool xfs_repair_fs(struct scrub_ctx *ctx);
> >  
> >  #endif /* XFS_SCRUB_XFS_SCRUB_H_ */
> > 
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