Hi Darrick.
This set looks mostly good, but there is one part in this patch (see below),
which is kind confusing to me:
> +#include <sys/statvfs.h>
> +#include "platform_defs.h"
> +#include "input.h"
> +#include "libfrog/paths.h"
> +#include "libfrog/ptvar.h"
> +#include "xfs_scrub.h"
> +#include "common.h"
> +#include "descr.h"
> +
> +/*
> + * Deferred String Description Renderer
> + * ====================================
> + * There are many places in xfs_scrub where some event occurred and we'd like
> + * to be able to print some sort of message describing what happened, and
> + * where. However, we don't know whether we're going to need the description
> + * of where ahead of time and there's little point in spending any time looking
> + * up gettext strings and formatting buffers until we actually need to.
> + *
> + * This code provides enough of a function closure that we are able to record
> + * some information about the program status but defer rendering the textual
> + * description until we know that we need it. Once we've rendered the string
> + * we can skip it for subsequent calls. We use per-thread storage for the
> + * message buffer to amortize the memory allocation across calls.
> + *
> + * On a clean filesystem this can reduce the xfs_scrub runtime by 7-10% by
> + * avoiding unnecessary work.
> + */
> +
> +static struct ptvar *descr_ptvar;
> +
> +/* Global buffer for when we aren't running in threaded mode. */
> +static char global_dsc_buf[DESCR_BUFSZ];
> +
> +/*
> + * Render a textual description string using the function and location stored
> + * in the description context.
> + */
> +const char *
> +__descr_render(
> + struct descr *dsc,
> + const char *file,
> + int line)
> +{
> + char *dsc_buf;
> + int ret;
> +
> + if (descr_ptvar) {
> + dsc_buf = ptvar_get(descr_ptvar, &ret);
> + if (ret)
> + return _("error finding description buffer");
> + } else
> + dsc_buf = global_dsc_buf;
> +
> + ret = dsc->fn(dsc->ctx, dsc_buf, DESCR_BUFSZ, dsc->where);
> + if (ret < 0) {
> + snprintf(dsc_buf, DESCR_BUFSZ,
> +_("error %d while rendering description at %s line %d\n"),
> + ret, file, line);
> + }
> +
> + return dsc_buf;
> +}
> +
> +/*
> + * Set a new location for this deferred-rendering string and discard any
> + * old rendering.
> + */
> +void
> +descr_set(
> + struct descr *dsc,
> + void *where)
> +{
> + dsc->where = where;
> +}
The comment on this function is actually confusing me. What exactly you mean by
'discard any old rendering' here?
Even though you use it on fresh created struct descr during the patch, the
comment gave me the impression you intend to use this function to set a new
location to an already created descriptor, but it's not clear to me, if, this is
the case, who is responsible to free up the memory previously associated with
the dsc->where pointer here, and so, it just feels like a potential memory leak
landmine here.
Maybe I've got confused by the comment or didn't fully understand your intention
here.
My apologies if I'm talking something nonsense, I'm trying to catch up with all
the scrub work yet.
Cheers.
> +
> +/* Allocate all the description string buffers. */
> +int
> +descr_init_phase(
> + struct scrub_ctx *ctx,
> + unsigned int nr_threads)
> +{
> + int ret;
> +
> + assert(descr_ptvar == NULL);
> + ret = ptvar_alloc(nr_threads, DESCR_BUFSZ, &descr_ptvar);
> + if (ret)
> + str_liberror(ctx, ret, _("creating description buffer"));
> +
> + return ret;
> +}
> +
> +/* Free all the description string buffers. */
> +void
> +descr_end_phase(void)
> +{
> + if (descr_ptvar)
> + ptvar_free(descr_ptvar);
> + descr_ptvar = NULL;
> +}
> diff --git a/scrub/descr.h b/scrub/descr.h
> new file mode 100644
> index 00000000..f1899b67
> --- /dev/null
> +++ b/scrub/descr.h
> @@ -0,0 +1,29 @@
> +/* SPDX-License-Identifier: GPL-2.0-or-later */
> +/*
> + * Copyright (C) 2019 Oracle. All Rights Reserved.
> + * Author: Darrick J. Wong <darrick.wong@xxxxxxxxxx>
> + */
> +#ifndef XFS_SCRUB_DESCR_H_
> +#define XFS_SCRUB_DESCR_H_
> +
> +typedef int (*descr_fn)(struct scrub_ctx *ctx, char *buf, size_t buflen,
> + void *data);
> +
> +struct descr {
> + struct scrub_ctx *ctx;
> + descr_fn fn;
> + void *where;
> +};
> +
> +#define DEFINE_DESCR(_name, _ctx, _fn) \
> + struct descr _name = { .ctx = (_ctx), .fn = (_fn) }
> +
> +const char *__descr_render(struct descr *dsc, const char *file, int line);
> +#define descr_render(dsc) __descr_render((dsc), __FILE__, __LINE__)
> +
> +void descr_set(struct descr *dsc, void *where);
> +
> +int descr_init_phase(struct scrub_ctx *ctx, unsigned int nr_threads);
> +void descr_end_phase(void);
> +
> +#endif /* XFS_SCRUB_DESCR_H_ */
> diff --git a/scrub/scrub.c b/scrub/scrub.c
> index 718f09b8..d9df1e5b 100644
> --- a/scrub/scrub.c
> +++ b/scrub/scrub.c
> @@ -20,37 +20,40 @@
> #include "scrub.h"
> #include "xfs_errortag.h"
> #include "repair.h"
> +#include "descr.h"
>
> /* Online scrub and repair wrappers. */
>
> /* Format a scrub description. */
> -static void
> +static int
> format_scrub_descr(
> struct scrub_ctx *ctx,
> char *buf,
> size_t buflen,
> - struct xfs_scrub_metadata *meta)
> + void *where)
> {
> + struct xfs_scrub_metadata *meta = where;
> const struct xfrog_scrub_descr *sc = &xfrog_scrubbers[meta->sm_type];
>
> switch (sc->type) {
> case XFROG_SCRUB_TYPE_AGHEADER:
> case XFROG_SCRUB_TYPE_PERAG:
> - snprintf(buf, buflen, _("AG %u %s"), meta->sm_agno,
> + return snprintf(buf, buflen, _("AG %u %s"), meta->sm_agno,
> _(sc->descr));
> break;
> case XFROG_SCRUB_TYPE_INODE:
> - scrub_render_ino_descr(ctx, buf, buflen,
> + return scrub_render_ino_descr(ctx, buf, buflen,
> meta->sm_ino, meta->sm_gen, "%s",
> _(sc->descr));
> break;
> case XFROG_SCRUB_TYPE_FS:
> - snprintf(buf, buflen, _("%s"), _(sc->descr));
> + return snprintf(buf, buflen, _("%s"), _(sc->descr));
> break;
> case XFROG_SCRUB_TYPE_NONE:
> assert(0);
> break;
> }
> + return -1;
> }
>
> /* Predicates for scrub flag state. */
> @@ -95,21 +98,24 @@ static inline bool needs_repair(struct xfs_scrub_metadata *sm)
> static inline void
> xfs_scrub_warn_incomplete_scrub(
> struct scrub_ctx *ctx,
> - const char *descr,
> + struct descr *dsc,
> struct xfs_scrub_metadata *meta)
> {
> if (is_incomplete(meta))
> - str_info(ctx, descr, _("Check incomplete."));
> + str_info(ctx, descr_render(dsc), _("Check incomplete."));
>
> if (is_suspicious(meta)) {
> if (debug)
> - str_info(ctx, descr, _("Possibly suspect metadata."));
> + str_info(ctx, descr_render(dsc),
> + _("Possibly suspect metadata."));
> else
> - str_warn(ctx, descr, _("Possibly suspect metadata."));
> + str_warn(ctx, descr_render(dsc),
> + _("Possibly suspect metadata."));
> }
>
> if (xref_failed(meta))
> - str_info(ctx, descr, _("Cross-referencing failed."));
> + str_info(ctx, descr_render(dsc),
> + _("Cross-referencing failed."));
> }
>
> /* Do a read-only check of some metadata. */
> @@ -119,16 +125,16 @@ xfs_check_metadata(
> struct xfs_scrub_metadata *meta,
> bool is_inode)
> {
> - char buf[DESCR_BUFSZ];
> + DEFINE_DESCR(dsc, ctx, format_scrub_descr);
> unsigned int tries = 0;
> int code;
> int error;
>
> assert(!debug_tweak_on("XFS_SCRUB_NO_KERNEL"));
> assert(meta->sm_type < XFS_SCRUB_TYPE_NR);
> - format_scrub_descr(ctx, buf, DESCR_BUFSZ, meta);
> + descr_set(&dsc, meta);
>
> - dbg_printf("check %s flags %xh\n", buf, meta->sm_flags);
> + dbg_printf("check %s flags %xh\n", descr_render(&dsc), meta->sm_flags);
> retry:
> error = xfrog_scrub_metadata(&ctx->mnt, meta);
> if (debug_tweak_on("XFS_SCRUB_FORCE_REPAIR") && !error)
> @@ -141,13 +147,13 @@ xfs_check_metadata(
> return CHECK_DONE;
> case ESHUTDOWN:
> /* FS already crashed, give up. */
> - str_error(ctx, buf,
> + str_error(ctx, descr_render(&dsc),
> _("Filesystem is shut down, aborting."));
> return CHECK_ABORT;
> case EIO:
> case ENOMEM:
> /* Abort on I/O errors or insufficient memory. */
> - str_errno(ctx, buf);
> + str_errno(ctx, descr_render(&dsc));
> return CHECK_ABORT;
> case EDEADLOCK:
> case EBUSY:
> @@ -161,7 +167,7 @@ _("Filesystem is shut down, aborting."));
> /* fall through */
> default:
> /* Operational error. */
> - str_errno(ctx, buf);
> + str_errno(ctx, descr_render(&dsc));
> return CHECK_DONE;
> }
> }
> @@ -179,7 +185,7 @@ _("Filesystem is shut down, aborting."));
> }
>
> /* Complain about incomplete or suspicious metadata. */
> - xfs_scrub_warn_incomplete_scrub(ctx, buf, meta);
> + xfs_scrub_warn_incomplete_scrub(ctx, &dsc, meta);
>
> /*
> * If we need repairs or there were discrepancies, schedule a
> @@ -187,7 +193,7 @@ _("Filesystem is shut down, aborting."));
> */
> if (is_corrupt(meta) || xref_disagrees(meta)) {
> if (ctx->mode < SCRUB_MODE_REPAIR) {
> - str_corrupt(ctx, buf,
> + str_corrupt(ctx, descr_render(&dsc),
> _("Repairs are required."));
> return CHECK_DONE;
> }
> @@ -203,7 +209,7 @@ _("Repairs are required."));
> if (ctx->mode != SCRUB_MODE_REPAIR) {
> if (!is_inode) {
> /* AG or FS metadata, always warn. */
> - str_info(ctx, buf,
> + str_info(ctx, descr_render(&dsc),
> _("Optimization is possible."));
> } else if (!ctx->preen_triggers[meta->sm_type]) {
> /* File metadata, only warn once per type. */
> @@ -656,9 +662,9 @@ xfs_repair_metadata(
> struct action_item *aitem,
> unsigned int repair_flags)
> {
> - char buf[DESCR_BUFSZ];
> struct xfs_scrub_metadata meta = { 0 };
> struct xfs_scrub_metadata oldm;
> + DEFINE_DESCR(dsc, ctx, format_scrub_descr);
> int error;
>
> assert(aitem->type < XFS_SCRUB_TYPE_NR);
> @@ -682,12 +688,13 @@ xfs_repair_metadata(
> return CHECK_RETRY;
>
> memcpy(&oldm, &meta, sizeof(oldm));
> - format_scrub_descr(ctx, buf, DESCR_BUFSZ, &meta);
> + descr_set(&dsc, &oldm);
>
> if (needs_repair(&meta))
> - str_info(ctx, buf, _("Attempting repair."));
> + str_info(ctx, descr_render(&dsc), _("Attempting repair."));
> else if (debug || verbose)
> - str_info(ctx, buf, _("Attempting optimization."));
> + str_info(ctx, descr_render(&dsc),
> + _("Attempting optimization."));
>
> error = xfrog_scrub_metadata(&ctx->mnt, &meta);
> if (error) {
> @@ -696,12 +703,12 @@ xfs_repair_metadata(
> case EBUSY:
> /* Filesystem is busy, try again later. */
> if (debug || verbose)
> - str_info(ctx, buf,
> + str_info(ctx, descr_render(&dsc),
> _("Filesystem is busy, deferring repair."));
> return CHECK_RETRY;
> case ESHUTDOWN:
> /* Filesystem is already shut down, abort. */
> - str_error(ctx, buf,
> + str_error(ctx, descr_render(&dsc),
> _("Filesystem is shut down, aborting."));
> return CHECK_ABORT;
> case ENOTTY:
> @@ -726,13 +733,13 @@ _("Filesystem is shut down, aborting."));
> /* fall through */
> case EINVAL:
> /* Kernel doesn't know how to repair this? */
> - str_corrupt(ctx, buf,
> + str_corrupt(ctx, descr_render(&dsc),
> _("Don't know how to fix; offline repair required."));
> return CHECK_DONE;
> case EROFS:
> /* Read-only filesystem, can't fix. */
> if (verbose || debug || needs_repair(&oldm))
> - str_error(ctx, buf,
> + str_error(ctx, descr_render(&dsc),
> _("Read-only filesystem; cannot make changes."));
> return CHECK_ABORT;
> case ENOENT:
> @@ -753,12 +760,12 @@ _("Read-only filesystem; cannot make changes."));
> */
> if (!(repair_flags & XRM_COMPLAIN_IF_UNFIXED))
> return CHECK_RETRY;
> - str_errno(ctx, buf);
> + str_errno(ctx, descr_render(&dsc));
> return CHECK_DONE;
> }
> }
> if (repair_flags & XRM_COMPLAIN_IF_UNFIXED)
> - xfs_scrub_warn_incomplete_scrub(ctx, buf, &meta);
> + xfs_scrub_warn_incomplete_scrub(ctx, &dsc, &meta);
> if (needs_repair(&meta)) {
> /*
> * Still broken; if we've been told not to complain then we
> @@ -767,14 +774,16 @@ _("Read-only filesystem; cannot make changes."));
> */
> if (!(repair_flags & XRM_COMPLAIN_IF_UNFIXED))
> return CHECK_RETRY;
> - str_corrupt(ctx, buf,
> + str_corrupt(ctx, descr_render(&dsc),
> _("Repair unsuccessful; offline repair required."));
> } else {
> /* Clean operation, no corruption detected. */
> if (needs_repair(&oldm))
> - record_repair(ctx, buf, _("Repairs successful."));
> + record_repair(ctx, descr_render(&dsc),
> + _("Repairs successful."));
> else
> - record_preen(ctx, buf, _("Optimization successful."));
> + record_preen(ctx, descr_render(&dsc),
> + _("Optimization successful."));
> }
> return CHECK_DONE;
> }
> diff --git a/scrub/xfs_scrub.c b/scrub/xfs_scrub.c
> index fe76d075..9945c7f4 100644
> --- a/scrub/xfs_scrub.c
> +++ b/scrub/xfs_scrub.c
> @@ -15,6 +15,7 @@
> #include "libfrog/paths.h"
> #include "xfs_scrub.h"
> #include "common.h"
> +#include "descr.h"
> #include "unicrash.h"
> #include "progress.h"
>
> @@ -467,8 +468,14 @@ run_scrub_phases(
> work_threads++;
> moveon = progress_init_phase(ctx, progress_fp, phase,
> max_work, rshift, work_threads);
> + if (!moveon)
> + break;
> + moveon = descr_init_phase(ctx, work_threads) == 0;
> } else {
> moveon = progress_init_phase(ctx, NULL, phase, 0, 0, 0);
> + if (!moveon)
> + break;
> + moveon = descr_init_phase(ctx, 1) == 0;
> }
> if (!moveon)
> break;
> @@ -480,6 +487,7 @@ _("Scrub aborted after phase %d."),
> break;
> }
> progress_end_phase();
> + descr_end_phase();
> moveon = phase_end(&pi, phase);
> if (!moveon)
> break;
>
--
Carlos
