[PATCH] cramfs mounts provide corrupted content since 2.6.15

Fix handling of cramfs images created by util-linux containing empty
regular files.  Images created by cramfstools 1.x were ok.

Fill out inode contents in cramfs_iget5_set() instead of get_cramfs_inode()
to prevent issues if cramfs_iget5_test() is called with I_LOCK|I_NEW still
set.

Signed-off-by: Dave Johnson <djohnson+linux-kernel@sw.starentnetworks.com>
Cc: Olaf Hering <olh@suse.de>
Cc: Chris Mason <mason@suse.com>
Cc: Andreas Gruenbacher <agruen@suse.de>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>

1 files changed, 29 insertions, 31 deletions

diff --git a/fs/cramfs/inode.c b/fs/cramfs/inode.c
index 7fe85415ae7c..8ad52f5bf255 100644
--- a/fs/cramfs/inode.c
+++ b/fs/cramfs/inode.c
@@ -36,7 +36,7 @@ static DECLARE_MUTEX(read_mutex);
 
 /* These two macros may change in future, to provide better st_ino
    semantics. */
-#define CRAMINO(x)      ((x)->offset?(x)->offset<<2:1)
+#define CRAMINO(x)      (((x)->offset && (x)->size)?(x)->offset<<2:1)
 #define OFFSET(x)       ((x)->i_ino)
 
 
@@ -66,8 +66,36 @@ static int cramfs_iget5_test(struct inode *inode, void *opaque)
 
 static int cramfs_iget5_set(struct inode *inode, void *opaque)
 {
+        static struct timespec zerotime;
         struct cramfs_inode *cramfs_inode = opaque;
+        inode->i_mode = cramfs_inode->mode;
+        inode->i_uid = cramfs_inode->uid;
+        inode->i_size = cramfs_inode->size;
+        inode->i_blocks = (cramfs_inode->size - 1) / 512 + 1;
+        inode->i_blksize = PAGE_CACHE_SIZE;
+        inode->i_gid = cramfs_inode->gid;
+        /* Struct copy intentional */
+        inode->i_mtime = inode->i_atime = inode->i_ctime = zerotime;
         inode->i_ino = CRAMINO(cramfs_inode);
+        /* inode->i_nlink is left 1 - arguably wrong for directories,
+           but it's the best we can do without reading the directory
+           contents.  1 yields the right result in GNU find, even
+           without -noleaf option. */
+        if (S_ISREG(inode->i_mode)) {
+                inode->i_fop = &generic_ro_fops;
+                inode->i_data.a_ops = &cramfs_aops;
+        } else if (S_ISDIR(inode->i_mode)) {
+                inode->i_op = &cramfs_dir_inode_operations;
+                inode->i_fop = &cramfs_directory_operations;
+        } else if (S_ISLNK(inode->i_mode)) {
+                inode->i_op = &page_symlink_inode_operations;
+                inode->i_data.a_ops = &cramfs_aops;
+        } else {
+                inode->i_size = 0;
+                inode->i_blocks = 0;
+                init_special_inode(inode, inode->i_mode,
+                        old_decode_dev(cramfs_inode->size));
+        }
         return 0;
 }
 
@@ -77,37 +105,7 @@ static struct inode *get_cramfs_inode(struct super_block *sb,
         struct inode *inode = iget5_locked(sb, CRAMINO(cramfs_inode),
                                             cramfs_iget5_test, cramfs_iget5_set,
                                             cramfs_inode);
-        static struct timespec zerotime;
-
         if (inode && (inode->i_state & I_NEW)) {
-                inode->i_mode = cramfs_inode->mode;
-                inode->i_uid = cramfs_inode->uid;
-                inode->i_size = cramfs_inode->size;
-                inode->i_blocks = (cramfs_inode->size - 1) / 512 + 1;
-                inode->i_blksize = PAGE_CACHE_SIZE;
-                inode->i_gid = cramfs_inode->gid;
-                /* Struct copy intentional */
-                inode->i_mtime = inode->i_atime = inode->i_ctime = zerotime;
-                inode->i_ino = CRAMINO(cramfs_inode);
-                /* inode->i_nlink is left 1 - arguably wrong for directories,
-                   but it's the best we can do without reading the directory
-                   contents.  1 yields the right result in GNU find, even
-                   without -noleaf option. */
-                if (S_ISREG(inode->i_mode)) {
-                        inode->i_fop = &generic_ro_fops;
-                        inode->i_data.a_ops = &cramfs_aops;
-                } else if (S_ISDIR(inode->i_mode)) {
-                        inode->i_op = &cramfs_dir_inode_operations;
-                        inode->i_fop = &cramfs_directory_operations;
-                } else if (S_ISLNK(inode->i_mode)) {
-                        inode->i_op = &page_symlink_inode_operations;
-                        inode->i_data.a_ops = &cramfs_aops;
-                } else {
-                        inode->i_size = 0;
-                        inode->i_blocks = 0;
-                        init_special_inode(inode, inode->i_mode,
-                                old_decode_dev(cramfs_inode->size));
-                }
                 unlock_new_inode(inode);
         }
         return inode;