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Date: Fri, 05 Oct 2007 17:58:41 -0700
From: Mingming Cao <cmm@...ibm.com>
To: jean-noel.cordenner@...l.net
Cc: linux-ext4@...r.kernel.org, linux-kernel@...r.kernel.org
Subject: Re: [PATCH 1/2] i_version update - vfs part
On Fri, 2007-10-05 at 17:28 +0200, Cordenner jean noel wrote:
> Hi,
>
Hi Jean Noel,
> This is an update of the i_version patch.
Just to make sure, is this vfs patch and next ext4 patch together going
to replace the 4 inode-version related patches currently in
ext4-patch-queue (and git tree)?
> The i_version field is a 64bit counter that is set on every inode
> creation and that is incremented every time the inode data is modified
> (similarly to the "ctime" time-stamp).
> The aim is to fulfill a NFSv4 requirement for rfc3530:
> "5.5. Mandatory Attributes - Definitions
> Name # DataType Access Description
> ___________________________________________________________________
> change 3 uint64 READ A value created by the
> server that the client can use to determine if file
> data, directory contents or attributes of the object
> have been modified. The servermay return the object's
> time_metadata attribute for this attribute's value but
> only if the filesystem object can not be updated more
> frequently than the resolution of time_metadata.
> "
>
> This first part deals with adding a flag in the super block and incrementing the i_version in the vfs.
>
> Signed-off-by: Jean Noel Cordenner <jean-noel.cordenner@...l.net>
> ---
> fs/inode.c | 23 +++++++++++++++++++++++
> fs/libfs.c | 12 ++++++++++++
> include/linux/fs.h | 3 +++
> 3 files changed, 38 insertions(+)
>
> Index: linux-2.6.23-rc8-ext4-i_version/fs/inode.c
> ===================================================================
> --- linux-2.6.23-rc8-ext4-i_version.orig/fs/inode.c 2007-09-26 14:41:41.000000000 +0200
> +++ linux-2.6.23-rc8-ext4-i_version/fs/inode.c 2007-10-05 16:14:41.000000000 +0200
> @@ -1216,6 +1216,24 @@
> EXPORT_SYMBOL(touch_atime);
>
> /**
> + * inode_inc_iversion - increments i_version
> + * @inode: inode that need to be updated
> + *
> + * Every time the inode is modified, the i_version field
> + * will be incremented.
> + * The filesystem has to be mounted with i_version flag
> + *
> + */
> +
> +void inode_inc_iversion(struct inode *inode)
> +{
> + spin_lock(&inode->i_lock);
> + inode->i_version++;
> + spin_unlock(&inode->i_lock);
> +}
I suspect we need a lock here, the places where need to update the
inode->i_version are already doing update for inode, mostly protected by
i_mutex.
You could remove the above function and update the counter directly at
the places it need to.
> +EXPORT_SYMBOL(inode_inc_iversion);
> +
Seems unnecessary.
> +/**
> * file_update_time - update mtime and ctime time
> * @file: file accessed
> *
> @@ -1249,6 +1267,11 @@
> sync_it = 1;
> }
>
> + if (IS_I_VERSION(inode)) {
> + inode_inc_iversion(inode);
> + sync_it = 1;
> + }
> +
> if (sync_it)
> mark_inode_dirty_sync(inode);
> }
> Index: linux-2.6.23-rc8-ext4-i_version/fs/libfs.c
> ===================================================================
> --- linux-2.6.23-rc8-ext4-i_version.orig/fs/libfs.c 2007-07-09 01:32:17.000000000 +0200
> +++ linux-2.6.23-rc8-ext4-i_version/fs/libfs.c 2007-09-26 14:51:08.000000000 +0200
> @@ -255,6 +255,10 @@
> struct inode *inode = old_dentry->d_inode;
>
> inode->i_ctime = dir->i_ctime = dir->i_mtime = CURRENT_TIME;
> + if (IS_I_VERSION(inode)) {
> + inode_inc_iversion(inode);
> + inode_inc_iversion(dir);
> + }
> inc_nlink(inode);
> atomic_inc(&inode->i_count);
> dget(dentry);
> @@ -287,6 +291,10 @@
> struct inode *inode = dentry->d_inode;
>
> inode->i_ctime = dir->i_ctime = dir->i_mtime = CURRENT_TIME;
> + if (IS_I_VERSION(inode)) {
> + inode_inc_iversion(inode);
> + inode_inc_iversion(dir);
> + }
> drop_nlink(inode);
> dput(dentry);
> return 0;
> @@ -323,6 +331,10 @@
>
> old_dir->i_ctime = old_dir->i_mtime = new_dir->i_ctime =
> new_dir->i_mtime = inode->i_ctime = CURRENT_TIME;
> + if (IS_I_VERSION(old_dir)) {
> + inode_inc_iversion(old_dir);
> + inode_inc_iversion(new_dir);
> + }
>
> return 0;
> }
Need to update the counter in libfs.c?
> Index: linux-2.6.23-rc8-ext4-i_version/include/linux/fs.h
> ===================================================================
> --- linux-2.6.23-rc8-ext4-i_version.orig/include/linux/fs.h 2007-09-26 14:46:15.000000000 +0200
> +++ linux-2.6.23-rc8-ext4-i_version/include/linux/fs.h 2007-09-26 14:51:08.000000000 +0200
> @@ -123,6 +123,7 @@
> #define MS_SLAVE (1<<19) /* change to slave */
> #define MS_SHARED (1<<20) /* change to shared */
> #define MS_RELATIME (1<<21) /* Update atime relative to mtime/ctime. */
> +#define MS_I_VERSION (1<<22) /* Update inode i_version field */
> #define MS_ACTIVE (1<<30)
> #define MS_NOUSER (1<<31)
>
> @@ -172,6 +173,7 @@
> ((inode)->i_flags & (S_SYNC|S_DIRSYNC)))
> #define IS_MANDLOCK(inode) __IS_FLG(inode, MS_MANDLOCK)
> #define IS_NOATIME(inode) __IS_FLG(inode, MS_RDONLY|MS_NOATIME)
> +#define IS_I_VERSION(inode) __IS_FLG(inode, MS_I_VERSION)
>
> #define IS_NOQUOTA(inode) ((inode)->i_flags & S_NOQUOTA)
> #define IS_APPEND(inode) ((inode)->i_flags & S_APPEND)
> @@ -1284,6 +1286,7 @@
> mark_inode_dirty(inode);
> }
>
> +extern void inode_inc_iversion(struct inode *inode);
> extern void touch_atime(struct vfsmount *mnt, struct dentry *dentry);
> static inline void file_accessed(struct file *file)
> {
>
>
> -
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