[PATCH] update description in Documentation/filesystems/vfs.txt

[PATCH] update description in Documentation/filesystems/vfs.txt

[Borislav Petkov]

While reading the said file I noticed some discrepancies between the actual
code and the info in the docs. Here's an update that attempts to match it to
the code in the current 2.6.22-rc5.

---
From: Borislav Petkov <bbpetkov@yahoo.de>

Update the description of struct file_system_type and get_sb() in
Documentation/filesystems/vfs.txt to match the current code.

Signed-off-by: Borislav Petkov <bbpetkov@yahoo.de>

--

Index: linux-2.6.22-rc5/Documentation/filesystems/vfs.txt
===================================================================
--- linux-2.6.22-rc5/Documentation/filesystems/vfs.txt.orig	2007-06-24 13:42:40.000000000 +0200
+++ linux-2.6.22-rc5/Documentation/filesystems/vfs.txt	2007-06-24 14:14:48.000000000 +0200
@@ -3,7 +3,7 @@
 
 	Original author: Richard Gooch <rgooch@atnf.csiro.au>
 
-		  Last updated on October 28, 2005
+		  Last updated on Juni 24, 2007.
 
   Copyright (C) 1999 Richard Gooch
   Copyright (C) 2005 Pekka Enberg
@@ -107,7 +107,7 @@
 struct file_system_type
 -----------------------
 
-This describes the filesystem. As of kernel 2.6.13, the following
+This describes the filesystem. As of kernel 2.6.22, the following
 members are defined:
 
 struct file_system_type {
@@ -119,6 +119,8 @@
         struct module *owner;
         struct file_system_type * next;
         struct list_head fs_supers;
+	struct lock_class_key s_lock_key;
+	struct lock_class_key s_umount_key;
 };
 
   name: the name of the filesystem type, such as "ext2", "iso9660",
@@ -137,11 +139,12 @@
 
   next: for internal VFS use: you should initialize this to NULL
 
+  s_lock_key, s_umount_key: lockdep-specific
+
 The get_sb() method has the following arguments:
 
-  struct super_block *sb: the superblock structure. This is partially
-	initialized by the VFS and the rest must be initialized by the
-	get_sb() method
+  struct file_system_type *fs_type: decribes the filesystem, partly initialized
+  	by the specific filesystem code
 
   int flags: mount flags
 
@@ -150,12 +153,13 @@
   void *data: arbitrary mount options, usually comes as an ASCII
 	string
 
-  int silent: whether or not to be silent on error
+  struct vfsmount *mnt: a vfs-internal representation of a mount point
 
 The get_sb() method must determine if the block device specified
-in the superblock contains a filesystem of the type the method
-supports. On success the method returns the superblock pointer, on
-failure it returns NULL.
+in the dev_name and fs_type contains a filesystem of the type the method
+supports. If it succeeds in opening the named block device, it initializes a
+struct super_block descriptor for the filesystem contained by the block device.
+On failure it returns an error.
 
 The most interesting member of the superblock structure that the
 get_sb() method fills in is the "s_op" field. This is a pointer to
-- 
Regards/Gruß,
    Boris.

Re: [PATCH] update description in Documentation/filesystems/vfs.txt

[Pekka Enberg]

Hi Borislav,

On 6/24/2007, "Borislav Petkov" <bbpetkov@yahoo.de> wrote:
> @@ -3,7 +3,7 @@
> 
>  	Original author: Richard Gooch <rgooch@atnf.csiro.au>
> 
> -		  Last updated on October 28, 2005
> +		  Last updated on Juni 24, 2007.

There's a typo here so do s/Juni/June/g please before sending to Andrew.
Other than that, looks good to me.

Acked-by: Pekka Enberg <penberg@cs.helsinki.fi>

[PATCH] update description in Documentation/filesystems/vfs.txt (typo fixed)

[Borislav Petkov]

On Mon, Jun 25, 2007 at 12:34:36PM +0300, Pekka Enberg wrote:
> 
> Hi Borislav,
> 
> On 6/24/2007, "Borislav Petkov" <bbpetkov@yahoo.de> wrote:
> > @@ -3,7 +3,7 @@
> > 
> >  	Original author: Richard Gooch <rgooch@atnf.csiro.au>
> > 
> > -		  Last updated on October 28, 2005
> > +		  Last updated on Juni 24, 2007.
> 
> There's a typo here so do s/Juni/June/g please before sending to Andrew.
> Other than that, looks good to me.
> 
> Acked-by: Pekka Enberg <penberg@cs.helsinki.fi>


Index: linux-2.6.22-rc5/Documentation/filesystems/vfs.txt
===================================================================
--- linux-2.6.22-rc5/Documentation/filesystems/vfs.txt.orig	2007-06-24 13:42:40.000000000 +0200
+++ linux-2.6.22-rc5/Documentation/filesystems/vfs.txt	2007-06-24 14:14:48.000000000 +0200
@@ -3,7 +3,7 @@
 
 	Original author: Richard Gooch <rgooch@atnf.csiro.au>
 
-		  Last updated on October 28, 2005
+		  Last updated on June 24, 2007.
 
   Copyright (C) 1999 Richard Gooch
   Copyright (C) 2005 Pekka Enberg
@@ -107,7 +107,7 @@
 struct file_system_type
 -----------------------
 
-This describes the filesystem. As of kernel 2.6.13, the following
+This describes the filesystem. As of kernel 2.6.22, the following
 members are defined:
 
 struct file_system_type {
@@ -119,6 +119,8 @@
         struct module *owner;
         struct file_system_type * next;
         struct list_head fs_supers;
+	struct lock_class_key s_lock_key;
+	struct lock_class_key s_umount_key;
 };
 
   name: the name of the filesystem type, such as "ext2", "iso9660",
@@ -137,11 +139,12 @@
 
   next: for internal VFS use: you should initialize this to NULL
 
+  s_lock_key, s_umount_key: lockdep-specific
+
 The get_sb() method has the following arguments:
 
-  struct super_block *sb: the superblock structure. This is partially
-	initialized by the VFS and the rest must be initialized by the
-	get_sb() method
+  struct file_system_type *fs_type: decribes the filesystem, partly initialized
+  	by the specific filesystem code
 
   int flags: mount flags
 
@@ -150,12 +153,13 @@
   void *data: arbitrary mount options, usually comes as an ASCII
 	string
 
-  int silent: whether or not to be silent on error
+  struct vfsmount *mnt: a vfs-internal representation of a mount point
 
 The get_sb() method must determine if the block device specified
-in the superblock contains a filesystem of the type the method
-supports. On success the method returns the superblock pointer, on
-failure it returns NULL.
+in the dev_name and fs_type contains a filesystem of the type the method
+supports. If it succeeds in opening the named block device, it initializes a
+struct super_block descriptor for the filesystem contained by the block device.
+On failure it returns an error.
 
 The most interesting member of the superblock structure that the
 get_sb() method fills in is the "s_op" field. This is a pointer to

-- 
Regards/Gruß,
    Boris.
-
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[PATCH] update Documentation/filesystems/vfs.txt (second part)

[Borislav Petkov]

---
From: Borislav Petkov <bbpetkov@yahoo.de>

Update the rest of Documentation/filesystems/vfs.txt

Signed-off-by: Borislav Petkov <bbpetkov@yahoo.de>

--

Index: linux-2.6.22-rc6/Documentation/filesystems/vfs.txt
===================================================================
--- linux-2.6.22-rc6/Documentation/filesystems/vfs.txt.orig	2007-07-01 08:47:29.000000000 +0200
+++ linux-2.6.22-rc6/Documentation/filesystems/vfs.txt	2007-07-01 08:47:48.000000000 +0200
@@ -193,7 +193,7 @@
 -----------------------
 
 This describes how the VFS can manipulate the superblock of your
-filesystem. As of kernel 2.6.13, the following members are defined:
+filesystem. As of kernel 2.6.22, the following members are defined:
 
 struct super_operations {
         struct inode *(*alloc_inode)(struct super_block *sb);
@@ -216,8 +216,6 @@
         void (*clear_inode) (struct inode *);
         void (*umount_begin) (struct super_block *);
 
-        void (*sync_inodes) (struct super_block *sb,
-                                struct writeback_control *wbc);
         int (*show_options)(struct seq_file *, struct vfsmount *);
 
         ssize_t (*quota_read)(struct super_block *, int, char *, size_t, loff_t);
@@ -300,9 +298,6 @@
 
   umount_begin: called when the VFS is unmounting a filesystem.
 
-  sync_inodes: called when the VFS is writing out dirty data associated with
-  	a superblock.
-
   show_options: called by the VFS to show mount options for /proc/<pid>/mounts.
 
   quota_read: called by the VFS to read from filesystem quota file.
@@ -324,7 +319,7 @@
 -----------------------
 
 This describes how the VFS can manipulate an inode in your
-filesystem. As of kernel 2.6.13, the following members are defined:
+filesystem. As of kernel 2.6.22, the following members are defined:
 
 struct inode_operations {
 	int (*create) (struct inode *,struct dentry *,int, struct nameidata *);
@@ -348,6 +343,7 @@
 	ssize_t (*getxattr) (struct dentry *, const char *, void *, size_t);
 	ssize_t (*listxattr) (struct dentry *, char *, size_t);
 	int (*removexattr) (struct dentry *, const char *);
+	void (*truncate_range)(struct inode *, loff_t, loff_t);
 };
 
 Again, all methods are called without any locks being held, unless
@@ -444,6 +440,9 @@
   removexattr: called by the VFS to remove an extended attribute from
   	a file. This method is called by removexattr(2) system call.
 
+  truncate_range: a method provided by the underlying filesystem to truncate a
+  	range of blocks , i.e. punch a hole somewhere in a file.
+
 
 The Address Space Object
 ========================
@@ -522,7 +521,7 @@
 -------------------------------
 
 This describes how the VFS can manipulate mapping of a file to page cache in
-your filesystem. As of kernel 2.6.16, the following members are defined:
+your filesystem. As of kernel 2.6.22, the following members are defined:
 
 struct address_space_operations {
 	int (*writepage)(struct page *page, struct writeback_control *wbc);
@@ -543,6 +542,7 @@
 			int);
 	/* migrate the contents of a page to the specified target */
 	int (*migratepage) (struct page *, struct page *);
+	int (*launder_page) (struct page *);
 };
 
   writepage: called by the VM to write a dirty page to backing store.
@@ -689,6 +689,10 @@
 	transfer any private data across and update any references
         that it has to the page.
 
+  launder_page: Called before freeing a page - it writes back the dirty page. To
+  	prevent redirtying the page, it is kept locked during the whole
+	operation.
+
 The File Object
 ===============
 
@@ -699,9 +703,10 @@
 ----------------------
 
 This describes how the VFS can manipulate an open file. As of kernel
-2.6.17, the following members are defined:
+2.6.22, the following members are defined:
 
 struct file_operations {
+	struct module *owner;
 	loff_t (*llseek) (struct file *, loff_t, int);
 	ssize_t (*read) (struct file *, char __user *, size_t, loff_t *);
 	ssize_t (*write) (struct file *, const char __user *, size_t, loff_t *);
@@ -728,10 +733,8 @@
 	int (*check_flags)(int);
 	int (*dir_notify)(struct file *filp, unsigned long arg);
 	int (*flock) (struct file *, int, struct file_lock *);
-	ssize_t (*splice_write)(struct pipe_inode_info *, struct file *, size_t, unsigned 
-int);
-	ssize_t (*splice_read)(struct file *, struct pipe_inode_info *, size_t, unsigned  
-int);
+	ssize_t (*splice_write)(struct pipe_inode_info *, struct file *, size_t, unsigned int);
+	ssize_t (*splice_read)(struct file *, struct pipe_inode_info *, size_t, unsigned int);
 };
 
 Again, all methods are called without any locks being held, unless
-- 
Regards/Gruß,
    Boris.
-
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