From c848046eb984fcbeeb78d681bf483aefbb35a013 Mon Sep 17 00:00:00 2001
From: David Sterba <dsterba@suse.cz>
Date: Thu, 11 Jun 2015 00:46:30 +0200
Subject: [PATCH] btrfs-progs: print error within test_dev_for_mkfs

The error string buffer passed as an argument is of a fixed size, though
we could print up to PATH_MAX + something bytes. Print the error message
directly.

Signed-off-by: David Sterba <dsterba@suse.cz>
---
 cmds-device.c  |  4 +---
 cmds-replace.c |  8 +++-----
 mkfs.c         |  4 +---
 utils.c        | 26 +++++++++++++-------------
 utils.h        |  2 +-
 5 files changed, 19 insertions(+), 25 deletions(-)

diff --git a/cmds-device.c b/cmds-device.c
index 4fa6b4a..3a10438 100644
--- a/cmds-device.c
+++ b/cmds-device.c
@@ -52,7 +52,6 @@ static int cmd_add_dev(int argc, char **argv)
 	DIR	*dirstream = NULL;
 	int discard = 1;
 	int force = 0;
-	char estr[100];
 
 	while (1) {
 		int c;
@@ -97,9 +96,8 @@ static int cmd_add_dev(int argc, char **argv)
 		int mixed = 0;
 		char *path;
 
-		res = test_dev_for_mkfs(argv[i], force, estr);
+		res = test_dev_for_mkfs(argv[i], force);
 		if (res) {
-			fprintf(stderr, "%s", estr);
 			ret++;
 			continue;
 		}
diff --git a/cmds-replace.c b/cmds-replace.c
index 75b131b..85365e3 100644
--- a/cmds-replace.c
+++ b/cmds-replace.c
@@ -142,7 +142,6 @@ static int cmd_start_replace(int argc, char **argv)
 	int do_not_background = 0;
 	int mixed = 0;
 	DIR *dirstream = NULL;
-	char estr[100]; /* check test_dev_for_mkfs() for error string size*/
 
 	while ((c = getopt(argc, argv, "Brf")) != -1) {
 		switch (c) {
@@ -256,11 +255,10 @@ static int cmd_start_replace(int argc, char **argv)
 		start_args.start.srcdevid = 0;
 	}
 
-	ret = test_dev_for_mkfs(dstdev, force_using_targetdev, estr);
-	if (ret) {
-		fprintf(stderr, "%s", estr);
+	ret = test_dev_for_mkfs(dstdev, force_using_targetdev);
+	if (ret)
 		goto leave_with_error;
-	}
+
 	fddstdev = open(dstdev, O_RDWR);
 	if (fddstdev < 0) {
 		fprintf(stderr, "Unable to open %s\n", dstdev);
diff --git a/mkfs.c b/mkfs.c
index 14b75bc..8bc7783 100644
--- a/mkfs.c
+++ b/mkfs.c
@@ -1335,10 +1335,8 @@ int main(int ac, char **av)
 	while (dev_cnt-- > 0) {
 		file = av[optind++];
 		if (is_block_device(file))
-			if (test_dev_for_mkfs(file, force_overwrite, estr)) {
-				fprintf(stderr, "Error: %s", estr);
+			if (test_dev_for_mkfs(file, force_overwrite))
 				exit(1);
-			}
 	}
 
 	optind = saved_optind;
diff --git a/utils.c b/utils.c
index 41a04bd..36aba39 100644
--- a/utils.c
+++ b/utils.c
@@ -2397,58 +2397,58 @@ int group_profile_max_safe_loss(u64 flags)
 	}
 }
 
-/* Check if disk is suitable for btrfs
+/*
+ * Check if a device is suitable for btrfs
  * returns:
- *  1: something is wrong, estr provides the error
+ *  1: something is wrong, an error is printed
  *  0: all is fine
  */
-int test_dev_for_mkfs(char *file, int force_overwrite, char *estr)
+int test_dev_for_mkfs(char *file, int force_overwrite)
 {
 	int ret, fd;
-	size_t sz = 100;
 	struct stat st;
 
 	ret = is_swap_device(file);
 	if (ret < 0) {
-		snprintf(estr, sz, "error checking %s status: %s\n", file,
+		fprintf(stderr, "ERROR: checking status of %s: %s\n", file,
 			strerror(-ret));
 		return 1;
 	}
 	if (ret == 1) {
-		snprintf(estr, sz, "%s is a swap device\n", file);
+		fprintf(stderr, "ERROR: %s is a swap device\n", file);
 		return 1;
 	}
 	if (!force_overwrite) {
 		if (check_overwrite(file)) {
-			snprintf(estr, sz, "Use the -f option to force overwrite.\n");
+			fprintf(stderr, "Use the -f option to force overwrite.\n");
 			return 1;
 		}
 	}
 	ret = check_mounted(file);
 	if (ret < 0) {
-		snprintf(estr, sz, "error checking %s mount status\n",
-			file);
+		fprintf(stderr, "ERROR: checking mount status of %s: %s\n",
+			file, strerror(-ret));
 		return 1;
 	}
 	if (ret == 1) {
-		snprintf(estr, sz, "%s is mounted\n", file);
+		fprintf(stderr, "ERROR: %s is mounted\n", file);
 		return 1;
 	}
 	/* check if the device is busy */
 	fd = open(file, O_RDWR|O_EXCL);
 	if (fd < 0) {
-		snprintf(estr, sz, "unable to open %s: %s\n", file,
+		fprintf(stderr, "ERROR: unable to open %s: %s\n", file,
 			strerror(errno));
 		return 1;
 	}
 	if (fstat(fd, &st)) {
-		snprintf(estr, sz, "unable to stat %s: %s\n", file,
+		fprintf(stderr, "ERROR: unable to stat %s: %s\n", file,
 			strerror(errno));
 		close(fd);
 		return 1;
 	}
 	if (!S_ISBLK(st.st_mode)) {
-		fprintf(stderr, "'%s' is not a block device\n", file);
+		fprintf(stderr, "ERROR: %s is not a block device\n", file);
 		close(fd);
 		return 1;
 	}
diff --git a/utils.h b/utils.h
index 50d1853..08518c5 100644
--- a/utils.h
+++ b/utils.h
@@ -156,7 +156,7 @@ int open_path_or_dev_mnt(const char *path, DIR **dirstream);
 u64 btrfs_device_size(int fd, struct stat *st);
 /* Helper to always get proper size of the destination string */
 #define strncpy_null(dest, src) __strncpy__null(dest, src, sizeof(dest))
-int test_dev_for_mkfs(char *file, int force_overwrite, char *estr);
+int test_dev_for_mkfs(char *file, int force_overwrite);
 int get_label_mounted(const char *mount_path, char *labelp);
 int test_num_disk_vs_raid(u64 metadata_profile, u64 data_profile,
 	u64 dev_cnt, int mixed, char *estr);
-- 
2.7.4