[v2,1/2] btrfs-progs: limit the max value of leafsize and nodesize

Commit Message

Robin Dong Sept. 28, 2012, 3:02 a.m. UTC

From: Robin Dong <[e-mail]>

Using mkfs.btrfs like:

        mkfs.btrfs -l 131072 /dev/sda

will return no error, but after mount it, the dmesg will report:

	BTRFS: couldn't mount because metadata blocksize (131072) was too large

The leafsize and nodesize are equal at present, so we just use one function
"check_leaf_or_node_size" to limit leaf and node size below BTRFS_MAX_METADATA_BLOCKSIZE.

Signed-off-by: Robin Dong <[e-mail]>
Reviewed-by: David Sterba <[e-mail]>
---
 ctree.h |    6 ++++++
 mkfs.c  |   29 +++++++++++++++++++++++------
 2 files changed, 29 insertions(+), 6 deletions(-)

Comments

David Sterba Sept. 30, 2012, 10:46 p.m. UTC | #1

On Fri, Sep 28, 2012 at 11:02:39AM +0800, Robin Dong wrote:
> From: Robin Dong <[e-mail]>
> --- a/mkfs.c
> +++ b/mkfs.c
> @@ -1201,6 +1201,27 @@ static int zero_output_file(int out_fd, u64 size, u32 sectorsize)
>  	return ret;
>  }
>  
> +static int check_leaf_or_node_size(u32 size, u32 sectorsize)
> +{
> +	if (size < sectorsize) {
> +		fprintf(stderr,
> +			"Illegal leafsize (or nodesize) %u (smaller than %u)\n",
> +			size, sectorsize);

First looking at the message, the absolute limit value might be
confusing, the condition is really 'if node/leaf is smaller than
sectorsize', and sectorsize will become a varaible eventually (though
now it's fixed to the system's PAGE_SIZE and 4k in most cases).

So, even if this will make the erro message more verbose, I suggest to
enhance the explanation with

"... (smaller than sectorsize %u)"

(If you se a better way how to format the value and the word, please don't
hasitate to change it.)

> +		return -1;
> +	} else if (size > BTRFS_MAX_METADATA_BLOCKSIZE) {
> +		fprintf(stderr,
> +			"Illegal leafsize (or nodesize) %u (larger than %u)\n",
> +			size, BTRFS_MAX_METADATA_BLOCKSIZE);
> +		return -1;
> +	} else if (size & (sectorsize - 1)) {
> +		fprintf(stderr,
> +			"Illegal leafsize (or nodesize) %u (not align to %u)\n",

align -> aligned

> +			size, sectorsize);
> +		return -1;
> +	}
> +	return 0;
> +}
> +

thanks,
david
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Patch

diff --git a/ctree.h b/ctree.h
index 7f55229..75c1e0a 100644
--- a/ctree.h
+++ b/ctree.h
@@ -111,6 +111,12 @@  struct btrfs_trans_handle;
 #define BTRFS_DEV_ITEMS_OBJECTID 1ULL
 
 /*
+ * the max metadata block size.  This limit is somewhat artificial,
+ * but the memmove costs go through the roof for larger blocks.
+ */
+#define BTRFS_MAX_METADATA_BLOCKSIZE 65536
+
+/*
  * we can actually store much bigger names, but lets not confuse the rest
  * of linux
  */
diff --git a/mkfs.c b/mkfs.c
index dff5eb8..8420482 100644
--- a/mkfs.c
+++ b/mkfs.c
@@ -1201,6 +1201,27 @@  static int zero_output_file(int out_fd, u64 size, u32 sectorsize)
 	return ret;
 }
 
+static int check_leaf_or_node_size(u32 size, u32 sectorsize)
+{
+	if (size < sectorsize) {
+		fprintf(stderr,
+			"Illegal leafsize (or nodesize) %u (smaller than %u)\n",
+			size, sectorsize);
+		return -1;
+	} else if (size > BTRFS_MAX_METADATA_BLOCKSIZE) {
+		fprintf(stderr,
+			"Illegal leafsize (or nodesize) %u (larger than %u)\n",
+			size, BTRFS_MAX_METADATA_BLOCKSIZE);
+		return -1;
+	} else if (size & (sectorsize - 1)) {
+		fprintf(stderr,
+			"Illegal leafsize (or nodesize) %u (not align to %u)\n",
+			size, sectorsize);
+		return -1;
+	}
+	return 0;
+}
+
 int main(int ac, char **av)
 {
 	char *file;
@@ -1291,14 +1312,10 @@  int main(int ac, char **av)
 		}
 	}
 	sectorsize = max(sectorsize, (u32)getpagesize());
-	if (leafsize < sectorsize || (leafsize & (sectorsize - 1))) {
-		fprintf(stderr, "Illegal leafsize %u\n", leafsize);
+	if (check_leaf_or_node_size(leafsize, sectorsize))
 		exit(1);
-	}
-	if (nodesize < sectorsize || (nodesize & (sectorsize - 1))) {
-		fprintf(stderr, "Illegal nodesize %u\n", nodesize);
+	if (check_leaf_or_node_size(nodesize, sectorsize))
 		exit(1);
-	}
 	ac = ac - optind;
 	if (ac == 0)
 		print_usage();