From 1b28dd73de42fae29e2fc18dde1e70d6daedecbd Mon Sep 17 00:00:00 2001 From: Qu Wenruo Date: Tue, 4 Feb 2025 18:46:57 +1030 Subject: [PATCH] btrfs-progs: scrub: add the new --limit option to set the throughput limit at runtime Add a new option `--limit ` to `btrfs scrub start`. This has some extra behavior differences compared to `btrfs scrub limit`: - Only set the value for the involved scrub device(s) If it's a full fs scrub, it will be the same as `btrfs scrub limit -a -l `. If it's a single device, it will bt the same as `btrfs scrub limit -d -l `. - Automatically revert to the old limit after scrub is finished - It only needs one single command line to set the limit Issue: #943 Signed-off-by: Qu Wenruo --- Documentation/btrfs-scrub.rst | 13 ++++++++++++- cmds/scrub.c | 34 ++++++++++++++++++++++++++++++++-- 2 files changed, 44 insertions(+), 3 deletions(-) diff --git a/Documentation/btrfs-scrub.rst b/Documentation/btrfs-scrub.rst index be106a551..fe8dd97c5 100644 --- a/Documentation/btrfs-scrub.rst +++ b/Documentation/btrfs-scrub.rst @@ -69,7 +69,7 @@ resume [-BdqrR] | .. _man-scrub-start: -start [-BdrRf] | +start [options] | Start a scrub on all devices of the mounted filesystem identified by *path* or on a single *device*. If a scrub is already running, the new one will not start. A device of an unmounted filesystem cannot be @@ -96,6 +96,17 @@ start [-BdrRf] | can avoid writes from scrub. -R raw print mode, print full data instead of summary + --limit + set the scrub throughput limit for each device. + + If the scrub is for the whole fs, it's the same as + :command:`btrfs scrub limit -a -l `. + If the scrub is for a single device, it's the same as + :command:`btrfs scrub limit -d -l `. + + The value is bytes per second, and accepts the usual KMGT prefixes. + After the scrub is finished, the throughput limit will be reset to + the old value of each device. -f force starting new scrub even if a scrub is already running, this can useful when scrub status file is damaged and reports a diff --git a/cmds/scrub.c b/cmds/scrub.c index b2cdc924d..23af16280 100644 --- a/cmds/scrub.c +++ b/cmds/scrub.c @@ -97,6 +97,7 @@ struct scrub_progress { pthread_mutex_t progress_mutex; int ioprio_class; int ioprio_classdata; + u64 old_limit; u64 limit; }; @@ -1230,7 +1231,6 @@ static int scrub_start(const struct cmd_struct *cmd, int argc, char **argv, int fdres = -1; int ret; pid_t pid; - int c; int i; int err = 0; int e_uncorrectable = 0; @@ -1265,11 +1265,22 @@ static int scrub_start(const struct cmd_struct *cmd, int argc, char **argv, struct scrub_progress_cycle spc; pthread_mutex_t spc_write_mutex = PTHREAD_MUTEX_INITIALIZER; void *terr; + u64 throughput_limit = 0; u64 devid; bool force = false; bool nothing_to_resume = false; - while ((c = getopt(argc, argv, "BdqrRc:n:f")) != -1) { + while (1) { + int c; + enum { GETOPT_VAL_LIMIT = GETOPT_VAL_FIRST }; + static const struct option long_options[] = { + {"limit", required_argument, NULL, GETOPT_VAL_LIMIT}, + { NULL, 0, NULL, 0 } + }; + + c = getopt_long(argc, argv, "BdqrRc:n:f", long_options, NULL); + if (c < 0) + break; switch (c) { case 'B': do_background = false; @@ -1297,6 +1308,9 @@ static int scrub_start(const struct cmd_struct *cmd, int argc, char **argv, case 'f': force = true; break; + case GETOPT_VAL_LIMIT: + throughput_limit = arg_strtou64_with_suffix(optarg); + break; default: usage_unknown_option(cmd, argv); } @@ -1389,6 +1403,13 @@ static int scrub_start(const struct cmd_struct *cmd, int argc, char **argv, for (i = 0; i < fi_args.num_devices; ++i) { devid = di_args[i].devid; + sp[i].old_limit = read_scrub_device_limit(fdmnt, devid); + ret = write_scrub_device_limit(fdmnt, devid, throughput_limit); + if (ret < 0) { + errno = -ret; + warning("failed to set scrub throughput limit on devid %llu: %m", + devid); + } ret = pthread_mutex_init(&sp[i].progress_mutex, NULL); if (ret) { errno = ret; @@ -1568,6 +1589,14 @@ static int scrub_start(const struct cmd_struct *cmd, int argc, char **argv, err = 0; for (i = 0; i < fi_args.num_devices; ++i) { + /* Revert to the older scrub limit. */ + ret = write_scrub_device_limit(fdmnt, di_args[i].devid, sp[i].old_limit); + if (ret < 0) { + errno = -ret; + warning("failed to reset scrub throughput limit on devid %llu: %m", + di_args[i].devid); + } + if (sp[i].skip) continue; devid = di_args[i].devid; @@ -1713,6 +1742,7 @@ static const char * const cmd_scrub_start_usage[] = { OPTLINE("-c", "set ioprio class (see ionice(1) manpage)"), OPTLINE("-n", "set ioprio classdata (see ionice(1) manpage)"), OPTLINE("-f", "force starting new scrub even if a scrub is already running this is useful when scrub stats record file is damaged"), + OPTLINE("--limit", "set the throughput limit for each device"), OPTLINE("-q", "deprecated, alias for global -q option"), HELPINFO_INSERT_GLOBALS, HELPINFO_INSERT_QUIET,