[5/5] Squashfs: Compute expected length from inode size rather than block length

diff --git a/fs/squashfs/file.c b/fs/squashfs/file.c
index cce3060..f1c1430 100644
--- a/fs/squashfs/file.c
+++ b/fs/squashfs/file.c
@@ -431,10 +431,9 @@  void squashfs_copy_cache(struct page *page, struct squashfs_cache_entry *buffer,
 }
 
 /* Read datablock stored packed inside a fragment (tail-end packed block) */
-static int squashfs_readpage_fragment(struct page *page)
+static int squashfs_readpage_fragment(struct page *page, int expected)
 {
 	struct inode *inode = page->mapping->host;
-	struct squashfs_sb_info *msblk = inode->i_sb->s_fs_info;
 	struct squashfs_cache_entry *buffer = squashfs_get_fragment(inode->i_sb,
 		squashfs_i(inode)->fragment_block,
 		squashfs_i(inode)->fragment_size);
@@ -445,23 +444,16 @@  static int squashfs_readpage_fragment(struct page *page)
 			squashfs_i(inode)->fragment_block,
 			squashfs_i(inode)->fragment_size);
 	else
-		squashfs_copy_cache(page, buffer, i_size_read(inode) &
-			(msblk->block_size - 1),
+		squashfs_copy_cache(page, buffer, expected,
 			squashfs_i(inode)->fragment_offset);
 
 	squashfs_cache_put(buffer);
 	return res;
 }
 
-static int squashfs_readpage_sparse(struct page *page, int index, int file_end)
+static int squashfs_readpage_sparse(struct page *page, int expected)
 {
-	struct inode *inode = page->mapping->host;
-	struct squashfs_sb_info *msblk = inode->i_sb->s_fs_info;
-	int bytes = index == file_end ?
-			(i_size_read(inode) & (msblk->block_size - 1)) :
-			 msblk->block_size;
-
-	squashfs_copy_cache(page, NULL, bytes, 0);
+	squashfs_copy_cache(page, NULL, expected, 0);
 	return 0;
 }
 
@@ -471,6 +463,9 @@  static int squashfs_readpage(struct file *file, struct page *page)
 	struct squashfs_sb_info *msblk = inode->i_sb->s_fs_info;
 	int index = page->index >> (msblk->block_log - PAGE_SHIFT);
 	int file_end = i_size_read(inode) >> msblk->block_log;
+	int expected = index == file_end ?
+			(i_size_read(inode) & (msblk->block_size - 1)) :
+			 msblk->block_size;
 	int res;
 	void *pageaddr;
 
@@ -489,11 +484,11 @@  static int squashfs_readpage(struct file *file, struct page *page)
 			goto error_out;
 
 		if (bsize == 0)
-			res = squashfs_readpage_sparse(page, index, file_end);
+			res = squashfs_readpage_sparse(page, expected);
 		else
-			res = squashfs_readpage_block(page, block, bsize);
+			res = squashfs_readpage_block(page, block, bsize, expected);
 	} else
-		res = squashfs_readpage_fragment(page);
+		res = squashfs_readpage_fragment(page, expected);
 
 	if (!res)
 		return 0;
diff --git a/fs/squashfs/file_cache.c b/fs/squashfs/file_cache.c
index f2310d2..a9ba8d9 100644
--- a/fs/squashfs/file_cache.c
+++ b/fs/squashfs/file_cache.c
@@ -20,7 +20,7 @@ 
 #include "squashfs.h"
 
 /* Read separately compressed datablock and memcopy into page cache */
-int squashfs_readpage_block(struct page *page, u64 block, int bsize)
+int squashfs_readpage_block(struct page *page, u64 block, int bsize, int expected)
 {
 	struct inode *i = page->mapping->host;
 	struct squashfs_cache_entry *buffer = squashfs_get_datablock(i->i_sb,
@@ -31,7 +31,7 @@  int squashfs_readpage_block(struct page *page, u64 block, int bsize)
 		ERROR("Unable to read page, block %llx, size %x\n", block,
 			bsize);
 	else
-		squashfs_copy_cache(page, buffer, buffer->length, 0);
+		squashfs_copy_cache(page, buffer, expected, 0);
 
 	squashfs_cache_put(buffer);
 	return res;
diff --git a/fs/squashfs/file_direct.c b/fs/squashfs/file_direct.c
index 0969902..80db1b8 100644
--- a/fs/squashfs/file_direct.c
+++ b/fs/squashfs/file_direct.c
@@ -21,10 +21,11 @@ 
 #include "page_actor.h"
 
 static int squashfs_read_cache(struct page *target_page, u64 block, int bsize,
-	int pages, struct page **page);
+	int pages, struct page **page, int bytes);
 
 /* Read separately compressed datablock directly into page cache */
-int squashfs_readpage_block(struct page *target_page, u64 block, int bsize)
+int squashfs_readpage_block(struct page *target_page, u64 block, int bsize,
+	int expected)
 
 {
 	struct inode *inode = target_page->mapping->host;
@@ -83,7 +84,7 @@  int squashfs_readpage_block(struct page *target_page, u64 block, int bsize)
 		 * using an intermediate buffer.
 		 */
 		res = squashfs_read_cache(target_page, block, bsize, pages,
-								page);
+							page, expected);
 		if (res < 0)
 			goto mark_errored;
 
@@ -95,6 +96,11 @@  int squashfs_readpage_block(struct page *target_page, u64 block, int bsize)
 	if (res < 0)
 		goto mark_errored;
 
+	if (res != expected) {
+		res = -EIO;
+		goto mark_errored;
+	}
+
 	/* Last page may have trailing bytes not filled */
 	bytes = res % PAGE_SIZE;
 	if (bytes) {
@@ -138,12 +144,12 @@  int squashfs_readpage_block(struct page *target_page, u64 block, int bsize)
 
 
 static int squashfs_read_cache(struct page *target_page, u64 block, int bsize,
-	int pages, struct page **page)
+	int pages, struct page **page, int bytes)
 {
 	struct inode *i = target_page->mapping->host;
 	struct squashfs_cache_entry *buffer = squashfs_get_datablock(i->i_sb,
 						 block, bsize);
-	int bytes = buffer->length, res = buffer->error, n, offset = 0;
+	int res = buffer->error, n, offset = 0;
 
 	if (res) {
 		ERROR("Unable to read page, block %llx, size %x\n", block,
diff --git a/fs/squashfs/squashfs.h b/fs/squashfs/squashfs.h
index d8d4372..f89f8a7 100644
--- a/fs/squashfs/squashfs.h
+++ b/fs/squashfs/squashfs.h
@@ -72,7 +72,7 @@  void squashfs_copy_cache(struct page *, struct squashfs_cache_entry *, int,
 				int);
 
 /* file_xxx.c */
-extern int squashfs_readpage_block(struct page *, u64, int);
+extern int squashfs_readpage_block(struct page *, u64, int, int);
 
 /* id.c */
 extern int squashfs_get_id(struct super_block *, unsigned int, unsigned int *);