Btrfs-progs: add option to skip whether a scrub has started/resumed in userspace

I hit a problem that i can not start scrub when i am trying to track
superblock generation mismatch problems.

The fact is that we are trying to check whether we have started a scrub operation
in userspace, this will make us can't start scrub if that record file is damaged
itself. By adding a option to skip that check, everything will be fine.

Signed-off-by: Wang Shilong <wangsl.fnst@cn.fujitsu.com>
Signed-off-by: David Sterba <dsterba@suse.cz>
Signed-off-by: Chris Mason <clm@fb.com>

diff --git a/cmds-scrub.c b/cmds-scrub.c
index b933770..25d4ef5 100644 (file)
--- a/cmds-scrub.c
+++ b/cmds-scrub.c
@@ -1096,9 +1096,10 @@ static int scrub_start(int argc, char **argv, int resume)
        void *terr;
        u64 devid;
        DIR *dirstream = NULL;
+       int force = 0;
 
        optind = 1;
-       while ((c = getopt(argc, argv, "BdqrRc:n:")) != -1) {
+       while ((c = getopt(argc, argv, "BdqrRc:n:f")) != -1) {
                switch (c) {
                case 'B':
                        do_background = 0;
@@ -1123,6 +1124,9 @@ static int scrub_start(int argc, char **argv, int resume)
                case 'n':
                        ioprio_classdata = (int)strtol(optarg, NULL, 10);
                        break;
+               case 'f':
+                       force = 1;
+                       break;
                case '?':
                default:
                        usage(resume ? cmd_scrub_resume_usage :
@@ -1195,7 +1199,7 @@ static int scrub_start(int argc, char **argv, int resume)
         * is a normal mode of operation to start scrub on multiple
         * single devices, there is no reason to prevent this.
         */
-       if (is_scrub_running_on_fs(&fi_args, di_args, past_scrubs)) {
+       if (!force && is_scrub_running_on_fs(&fi_args, di_args, past_scrubs)) {
                ERR(!do_quiet,
                    "ERROR: scrub is already running.\n"
                    "To cancel use 'btrfs scrub cancel %s'.\n"
@@ -1507,7 +1511,7 @@ out:
 }
 
 static const char * const cmd_scrub_start_usage[] = {
-       "btrfs scrub start [-BdqrR] [-c ioprio_class -n ioprio_classdata] <path>|<device>",
+       "btrfs scrub start [-BdqrRf] [-c ioprio_class -n ioprio_classdata] <path>|<device>",
        "Start a new scrub",
        "",
        "-B     do not background",
@@ -1517,6 +1521,8 @@ static const char * const cmd_scrub_start_usage[] = {
        "-R     raw print mode, print full data instead of summary"
        "-c     set ioprio class (see ionice(1) manpage)",
        "-n     set ioprio classdata (see ionice(1) manpage)",
+       "-f     force to skip checking whether scrub has started/resumed in userspace ",
+       "       this is useful when scrub stats record file is damaged",
        NULL
 };
 

diff --git a/man/btrfs.8.in b/man/btrfs.8.in
index b620348..d5515e0 100644 (file)
--- a/man/btrfs.8.in
+++ b/man/btrfs.8.in
@@ -58,7 +58,7 @@ btrfs \- control a btrfs filesystem
 \fBbtrfs\fP \fBdevice stats\fP [-z] {\fI<path>\fP|\fI<device>\fP}
 .PP
 .PP
-\fBbtrfs\fP \fBscrub start\fP [-BdqrR] [-c \fIioprio_class\fP -n \fIioprio_classdata\fP] {\fI<path>\fP|\fI<device>\fP}
+\fBbtrfs\fP \fBscrub start\fP [-BdqrRf] [-c \fIioprio_class\fP -n \fIioprio_classdata\fP] {\fI<path>\fP|\fI<device>\fP}
 .PP
 \fBbtrfs\fP \fBscrub cancel\fP {\fI<path>\fP|\fI<device>\fP}
 .PP
@@ -461,6 +461,9 @@ manpage).
 Set IO priority classdata (see
 .BR ionice (1)
 manpage).
+.IP "\fB-f\fP" 5
+force to check whether scrub has started or resumed in userspace.
+this is useful when scrub stat record file is damaged.
 .RE
 .TP