[PATCH] btrfs-progs: print-tree: fix chunk/block group flags output

[Qu Wenruo <wqu@suse.com>]

[BUG]
Commit ("btrfs-progs: use raid table for profile names in
print-tree.c") introduced one bug in block group and chunk flags output
and changed the behavior:

	item 1 key (FIRST_CHUNK_TREE CHUNK_ITEM 13631488) itemoff 16105 itemsize 80
		length 8388608 owner 2 stripe_len 65536 type SINGLE
		...
	item 2 key (FIRST_CHUNK_TREE CHUNK_ITEM 22020096) itemoff 15993 itemsize 112
		length 8388608 owner 2 stripe_len 65536 type DUP
		...
	item 3 key (FIRST_CHUNK_TREE CHUNK_ITEM 30408704) itemoff 15881 itemsize 112
		length 268435456 owner 2 stripe_len 65536 type DUP
		...

Note that, the flag string only contains the profile (SINGLE/DUP/etc...)
no type (DATA/METADATA/SYSTEM).

And we have new "SINGLE" string, even that profile has no extra bit to
indicate that.

[CAUSE]
The "SINGLE" part is caused by the raid array which has a name for
SINGLE profile, even it doesn't have corresponding bit.

The missing type string is caused by a code bug:

		strcpy(buf, name);
		while (*tmp) {
			*tmp = toupper(*tmp);
			tmp++;
		}
		strcpy(ret, buf);

The last strcpy() call overrides the existing string in @ret.

[FIX]
- Enhance string handling using strn*()/snprintf()

- Add extra "UKNOWN.0x%llx" output for unknown profiles

- Call proper strncat() to merge type and profile

- Add extra handling for "SINGLE" to keep the old output

Signed-off-by: Qu Wenruo <wqu@suse.com>
---
 kernel-shared/print-tree.c | 47 +++++++++++++++++++++++---------------
 1 file changed, 29 insertions(+), 18 deletions(-)

diff --git a/kernel-shared/print-tree.c b/kernel-shared/print-tree.c
index 67b654e6d2d5..39655590272e 100644
--- a/kernel-shared/print-tree.c
+++ b/kernel-shared/print-tree.c
@@ -159,40 +159,51 @@ static void print_inode_ref_item(struct extent_buffer *eb, u32 size,
 	}
 }
 
-/* Caller should ensure sizeof(*ret)>=21 "DATA|METADATA|RAID10" */
+/* The minimal length for the string buffer of block group/chunk flags */
+#define BG_FLAG_STRING_LEN	64
+
 static void bg_flags_to_str(u64 flags, char *ret)
 {
 	int empty = 1;
+	char profile[BG_FLAG_STRING_LEN] = {};
 	const char *name;
 
+	ret[0] = '\0';
 	if (flags & BTRFS_BLOCK_GROUP_DATA) {
 		empty = 0;
-		strcpy(ret, "DATA");
+		strncpy(ret, "DATA", BG_FLAG_STRING_LEN);
 	}
 	if (flags & BTRFS_BLOCK_GROUP_METADATA) {
 		if (!empty)
-			strcat(ret, "|");
-		strcat(ret, "METADATA");
+			strncat(ret, "|", BG_FLAG_STRING_LEN);
+		strncat(ret, "METADATA", BG_FLAG_STRING_LEN);
 	}
 	if (flags & BTRFS_BLOCK_GROUP_SYSTEM) {
 		if (!empty)
-			strcat(ret, "|");
-		strcat(ret, "SYSTEM");
+			strncat(ret, "|", BG_FLAG_STRING_LEN);
+		strncat(ret, "SYSTEM", BG_FLAG_STRING_LEN);
 	}
-	strcat(ret, "|");
 	name = btrfs_bg_type_to_raid_name(flags);
 	if (!name) {
-		strcat(ret, "UNKNOWN");
+		snprintf(profile, BG_FLAG_STRING_LEN, "UNKNOWN.0x%llx",
+			 flags & BTRFS_BLOCK_GROUP_PROFILE_MASK);
 	} else {
-		char buf[32];
-		char *tmp = buf;
+		int i;
 
-		strcpy(buf, name);
-		while (*tmp) {
-			*tmp = toupper(*tmp);
-			tmp++;
-		}
-		strcpy(ret, buf);
+		/*
+		 * Special handing for SINGLE profile, we don't output "SINGLE"
+		 * for SINGLE profile, since there is no such bit for it.
+		 * Thus here we only fill @profile if it's not single.
+		 */
+		if (strncmp(name, "single", strlen("single")) != 0)
+			strncpy(profile, name, BG_FLAG_STRING_LEN);
+
+		for (i = 0; i < BG_FLAG_STRING_LEN && profile[i]; i++)
+			profile[i] = toupper(profile[i]);
+	}
+	if (profile[0]) {
+		strncat(ret, "|", BG_FLAG_STRING_LEN);
+		strncat(ret, profile, BG_FLAG_STRING_LEN);
 	}
 }
 
@@ -215,7 +226,7 @@ void print_chunk_item(struct extent_buffer *eb, struct btrfs_chunk *chunk)
 	u16 num_stripes = btrfs_chunk_num_stripes(eb, chunk);
 	int i;
 	u32 chunk_item_size;
-	char chunk_flags_str[32] = {0};
+	char chunk_flags_str[BG_FLAG_STRING_LEN] = {};
 
 	/* The chunk must contain at least one stripe */
 	if (num_stripes < 1) {
@@ -986,7 +997,7 @@ static void print_block_group_item(struct extent_buffer *eb,
 		struct btrfs_block_group_item *bgi)
 {
 	struct btrfs_block_group_item bg_item;
-	char flags_str[256];
+	char flags_str[BG_FLAG_STRING_LEN] = {};
 
 	read_extent_buffer(eb, &bg_item, (unsigned long)bgi, sizeof(bg_item));
 	memset(flags_str, 0, sizeof(flags_str));
-- 
2.33.0