Squashfs: check page size is not larger than the filesystem block size

Normally the block size (by default 128K) will be larger than the
page size, unless a non-standard block size has been specified in
Mksquashfs, and the page size is larger than 4K.

Signed-off-by: Phillip Lougher <phillip@lougher.demon.co.uk>

1 files changed, 10 insertions, 0 deletions

diff --git a/fs/squashfs/super.c b/fs/squashfs/super.c
index ffa6edcd2d0c..0adc624c956f 100644
--- a/fs/squashfs/super.c
+++ b/fs/squashfs/super.c
@@ -157,6 +157,16 @@ static int squashfs_fill_super(struct super_block *sb, void *data, int silent)
         if (msblk->block_size > SQUASHFS_FILE_MAX_SIZE)
                 goto failed_mount;
 
+        /*
+         * Check the system page size is not larger than the filesystem
+         * block size (by default 128K).  This is currently not supported.
+         */
+        if (PAGE_CACHE_SIZE > msblk->block_size) {
+                ERROR("Page size > filesystem block size (%d).  This is "
+                        "currently not supported!\n", msblk->block_size);
+                goto failed_mount;
+        }
+
         msblk->block_log = le16_to_cpu(sblk->block_log);
         if (msblk->block_log > SQUASHFS_FILE_MAX_LOG)
                 goto failed_mount;