cramfs: fix named-pipe handling
Al Viro [Wed, 20 Aug 2008 21:09:24 +0000 (14:09 -0700)]
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>

fs/cramfs/inode.c

index 0c3b618..f40423e 100644 (file)
@@ -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,