cramfs: fix named-pipe handling

After commit a97c9bf33f4612e2aed6f000f6b1d268b6814f3c (fix cramfs
making duplicate entries in inode cache) in kernel 2.6.14, named-pipe
on cramfs does not work properly.

It seems the commit make all named-pipe on cramfs share their inode
(and named-pipe buffer).

Make ..._test() refuse to merge inodes with ->i_ino == 1, take inode setup
back to get_cramfs_inode() and make ->drop_inode() evict ones with ->i_ino
== 1 immediately.

Reported-by: Atsushi Nemoto <anemo@mba.ocn.ne.jp>
Cc: Al Viro <viro@zeniv.linux.org.uk>
Cc: <stable@kernel.org>		[2.6.14 and later]
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

1 files changed, 38 insertions, 46 deletions

diff --git a/fs/cramfs/inode.c b/fs/cramfs/inode.c
index 0c3b618c15b..f40423eb1a1 100644
--- a/fs/cramfs/inode.c
+++ b/fs/cramfs/inode.c
@@ -43,58 +43,13 @@ static DEFINE_MUTEX(read_mutex);
 static int cramfs_iget5_test(struct inode *inode, void *opaque)
 {
         struct cramfs_inode *cramfs_inode = opaque;
-
-        if (inode->i_ino != CRAMINO(cramfs_inode))
-                return 0; /* does not match */
-
-        if (inode->i_ino != 1)
-                return 1;
-
-        /* all empty directories, char, block, pipe, and sock, share inode #1 */
-
-        if ((inode->i_mode != cramfs_inode->mode) ||
-            (inode->i_gid != cramfs_inode->gid) ||
-            (inode->i_uid != cramfs_inode->uid))
-                return 0; /* does not match */
-
-        if ((S_ISCHR(inode->i_mode) || S_ISBLK(inode->i_mode)) &&
-            (inode->i_rdev != old_decode_dev(cramfs_inode->size)))
-                return 0; /* does not match */
-
-        return 1; /* matches */
+        return inode->i_ino == CRAMINO(cramfs_inode) && inode->i_ino != 1;
 }
 
 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_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;
 }
 
@@ -104,12 +59,48 @@ 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_gid = cramfs_inode->gid;
+                /* Struct copy intentional */
+                inode->i_mtime = inode->i_atime = inode->i_ctime = zerotime;
+                /* 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;
 }
 
+static void cramfs_drop_inode(struct inode *inode)
+{
+        if (inode->i_ino == 1)
+                generic_delete_inode(inode);
+        else
+                generic_drop_inode(inode);
+}
+
 /*
  * We have our own block cache: don't fill up the buffer cache
  * with the rom-image, because the way the filesystem is set
@@ -534,6 +525,7 @@ static const struct super_operations cramfs_ops = {
         .put_super      = cramfs_put_super,
         .remount_fs     = cramfs_remount,
         .statfs         = cramfs_statfs,
+        .drop_inode     = cramfs_drop_inode,
 };
 
 static int cramfs_get_sb(struct file_system_type *fs_type,