[PATCH] fsck: add --workers option to configure worker threads

[Utkal Singh]

Add a --workers=# command-line option to fsck.erofs to allow users
to configure the number of worker threads used during verification.

Parse the value using strtoul() and validate it against UINT_MAX
before storing it in fsckcfg.nr_workers. Return -EINVAL for invalid
inputs (non-numeric characters or out-of-range values).

Signed-off-by: Utkal Singh <singhutkal015 at gmail.com>
---
 fsck/main.c | 13 +++++++++++++
 1 file changed, 13 insertions(+)

diff --git a/fsck/main.c b/fsck/main.c
index 16cc627..37e21f4 100644
--- a/fsck/main.c
+++ b/fsck/main.c
@@ -4,6 +4,7 @@
  * Author: Daeho Jeong <daehojeong at google.com>
  */
 #include <stdlib.h>
+#include <limits.h>
 #include <getopt.h>
 #include <time.h>
 #include <utime.h>
@@ -42,6 +43,7 @@ struct erofsfsck_cfg {
 	erofs_nid_t nid;
 	const char *inode_path;
 	bool nosbcrc;
+	unsigned int nr_workers;
 };
 static struct erofsfsck_cfg fsckcfg;
 
@@ -64,6 +66,7 @@ static struct option long_options[] = {
 	{"nid", required_argument, 0, 15},
 	{"path", required_argument, 0, 16},
 	{"no-sbcrc", no_argument, 0, 512},
+	{"workers", required_argument, 0, 17},
 	{0, 0, 0, 0},
 };
 
@@ -117,6 +120,7 @@ static void usage(int argc, char **argv)
 		" --nid=#                check or extract from the target inode of nid #\n"
 		" --path=X               check or extract from the target inode of path X\n"
 		" --no-sbcrc             bypass the superblock checksum verification\n"
+		" --workers=#            number of worker threads\n"
 		" --[no-]xattrs          whether to dump extended attributes (default off)\n"
 		"\n"
 		" -a, -A, -y             no-op, for compatibility with fsck of other filesystems\n"
@@ -257,6 +261,15 @@ static int erofsfsck_parse_options_cfg(int argc, char **argv)
 		case 16:
 			fsckcfg.inode_path = optarg;
 			break;
+		case 17: {
+			char *endptr;
+			unsigned long v = strtoul(optarg, &endptr, 0);
+
+			if (*endptr || v > UINT_MAX)
+				return -EINVAL;
+			fsckcfg.nr_workers = v;
+			break;
+		}
 		case 512:
 			fsckcfg.nosbcrc = true;
 			break;
-- 
2.43.0