Re: [patch] O_SYNC patch 3/3, add inode dirty buffer list support to ext2

["Jeff V. Merkey" <jmerkey@vger.timpanogas.org>]

On Wed, Nov 22, 2000 at 11:26:46AM +0000, Stephen C. Tweedie wrote:
> Hi,
> 
> This final part of the O_SYNC patches adds calls to ext2, and to
> generic_commit_write, to record dirty buffers against the owning
> inode.  It also removes most of fs/ext2/fsync.c, which now simply
> calls the generic sync code.
> 
> --Stephen


Stephen,

I have not implemented O_SYNC in NWFS, but it looks like I need to add it 
before posting the final patches.  This patch appears to force write-through 
of only dirty inodes, and allow reads to continue from cache.  Is this
assumption correct, and does this comply with TPC rules for ORACLE and 
other DBMS benchmarks?  It looks like a good patch that will perform 
very fast for O_SYNC.

Jeff


> 
> 2.4.0test11.02.ext2-osync.diff :
> 
> 
> --- linux-2.4.0-test11/fs/buffer.c.~1~	Tue Nov 21 15:51:17 2000
> +++ linux-2.4.0-test11/fs/buffer.c	Tue Nov 21 16:35:35 2000
> @@ -1727,6 +1727,7 @@
>  			set_bit(BH_Uptodate, &bh->b_state);
>  			if (!atomic_set_buffer_dirty(bh)) {
>  				__mark_dirty(bh);
> +				buffer_insert_inode_queue(bh, inode);
>  				need_balance_dirty = 1;
>  			}
>  		}
> --- linux-2.4.0-test11/fs/ext2/fsync.c.~1~	Tue Nov 21 15:47:48 2000
> +++ linux-2.4.0-test11/fs/ext2/fsync.c	Tue Nov 21 16:01:15 2000
> @@ -28,98 +28,6 @@
>  #include <linux/smp_lock.h>
>  
>  
> -#define blocksize	(EXT2_BLOCK_SIZE(inode->i_sb))
> -#define addr_per_block	(EXT2_ADDR_PER_BLOCK(inode->i_sb))
> -
> -static int sync_indirect(struct inode * inode, u32 * block, int wait)
> -{
> -	struct buffer_head * bh;
> -	
> -	if (!*block)
> -		return 0;
> -	bh = get_hash_table(inode->i_dev, le32_to_cpu(*block), blocksize);
> -	if (!bh)
> -		return 0;
> -	if (wait && buffer_req(bh) && !buffer_uptodate(bh)) {
> -		/* There can be a parallell read(2) that started read-I/O
> -		   on the buffer so we can't assume that there's been
> -		   an I/O error without first waiting I/O completation. */
> -		wait_on_buffer(bh);
> -		if (!buffer_uptodate(bh))
> -		{
> -			brelse (bh);
> -			return -1;
> -		}
> -	}
> -	if (wait || !buffer_uptodate(bh) || !buffer_dirty(bh)) {
> -		if (wait)
> -			/* when we return from fsync all the blocks
> -			   must be _just_ stored on disk */
> -			wait_on_buffer(bh);
> -		brelse(bh);
> -		return 0;
> -	}
> -	ll_rw_block(WRITE, 1, &bh);
> -	atomic_dec(&bh->b_count);
> -	return 0;
> -}
> -
> -static int sync_iblock(struct inode * inode, u32 * iblock, 
> -			struct buffer_head ** bh, int wait) 
> -{
> -	int rc, tmp;
> -	
> -	*bh = NULL;
> -	tmp = le32_to_cpu(*iblock);
> -	if (!tmp)
> -		return 0;
> -	rc = sync_indirect(inode, iblock, wait);
> -	if (rc)
> -		return rc;
> -	*bh = bread(inode->i_dev, tmp, blocksize);
> -	if (!*bh)
> -		return -1;
> -	return 0;
> -}
> -
> -static int sync_dindirect(struct inode * inode, u32 * diblock, int wait)
> -{
> -	int i;
> -	struct buffer_head * dind_bh;
> -	int rc, err = 0;
> -
> -	rc = sync_iblock(inode, diblock, &dind_bh, wait);
> -	if (rc || !dind_bh)
> -		return rc;
> -	
> -	for (i = 0; i < addr_per_block; i++) {
> -		rc = sync_indirect(inode, ((u32 *) dind_bh->b_data) + i, wait);
> -		if (rc)
> -			err = rc;
> -	}
> -	brelse(dind_bh);
> -	return err;
> -}
> -
> -static int sync_tindirect(struct inode * inode, u32 * tiblock, int wait)
> -{
> -	int i;
> -	struct buffer_head * tind_bh;
> -	int rc, err = 0;
> -
> -	rc = sync_iblock(inode, tiblock, &tind_bh, wait);
> -	if (rc || !tind_bh)
> -		return rc;
> -	
> -	for (i = 0; i < addr_per_block; i++) {
> -		rc = sync_dindirect(inode, ((u32 *) tind_bh->b_data) + i, wait);
> -		if (rc)
> -			err = rc;
> -	}
> -	brelse(tind_bh);
> -	return err;
> -}
> -
>  /*
>   *	File may be NULL when we are called. Perhaps we shouldn't
>   *	even pass file to fsync ?
> @@ -127,34 +35,20 @@
>  
>  int ext2_sync_file(struct file * file, struct dentry *dentry, int datasync)
>  {
> -	int wait, err = 0;
>  	struct inode *inode = dentry->d_inode;
> +	return ext2_fsync_inode(inode, datasync);
> +}
>  
> -	lock_kernel();
> -	if (S_ISLNK(inode->i_mode) && !(inode->i_blocks))
> -		/*
> -		 * Don't sync fast links!
> -		 */
> -		goto skip;
> -
> -	err = generic_buffer_fdatasync(inode, 0, ~0UL);
> -
> -	for (wait=0; wait<=1; wait++)
> -	{
> -		err |= sync_indirect(inode,
> -				     inode->u.ext2_i.i_data+EXT2_IND_BLOCK,
> -				     wait);
> -		err |= sync_dindirect(inode,
> -				      inode->u.ext2_i.i_data+EXT2_DIND_BLOCK, 
> -				      wait);
> -		err |= sync_tindirect(inode, 
> -				      inode->u.ext2_i.i_data+EXT2_TIND_BLOCK, 
> -				      wait);
> -	}
> -skip:
> -	if ((inode->i_state & I_DIRTY_DATASYNC) || 
> -	    ((inode->i_state & I_DIRTY) && !datasync))
> -		err |= ext2_sync_inode (inode);
> -	unlock_kernel();
> +int ext2_fsync_inode(struct inode *inode, int datasync)
> +{
> +	int err;
> +	
> +	err  = fsync_inode_buffers(inode);
> +	if (!(inode->i_state & I_DIRTY))
> +		return err;
> +	if (datasync && !(inode->i_state & I_DIRTY_DATASYNC))
> +		return err;
> +	
> +	err |= ext2_sync_inode(inode);
>  	return err ? -EIO : 0;
>  }
> --- linux-2.4.0-test11/fs/ext2/inode.c.~1~	Tue Nov 21 15:40:22 2000
> +++ linux-2.4.0-test11/fs/ext2/inode.c	Tue Nov 21 16:01:15 2000
> @@ -404,7 +404,7 @@
>  		branch[n].p = (u32*) bh->b_data + offsets[n];
>  		*branch[n].p = branch[n].key;
>  		mark_buffer_uptodate(bh, 1);
> -		mark_buffer_dirty(bh);
> +		mark_buffer_dirty_inode(bh, inode);
>  		if (IS_SYNC(inode) || inode->u.ext2_i.i_osync) {
>  			ll_rw_block (WRITE, 1, &bh);
>  			wait_on_buffer (bh);
> @@ -469,7 +469,7 @@
>  
>  	/* had we spliced it onto indirect block? */
>  	if (where->bh) {
> -		mark_buffer_dirty(where->bh);
> +		mark_buffer_dirty_inode(where->bh, inode);
>  		if (IS_SYNC(inode) || inode->u.ext2_i.i_osync) {
>  			ll_rw_block (WRITE, 1, &where->bh);
>  			wait_on_buffer(where->bh);
> @@ -591,7 +591,7 @@
>  				wait_on_buffer(bh);
>  			memset(bh->b_data, 0, inode->i_sb->s_blocksize);
>  			mark_buffer_uptodate(bh, 1);
> -			mark_buffer_dirty(bh);
> +			mark_buffer_dirty_inode(bh, inode);
>  		}
>  		return bh;
>  	}
> @@ -907,7 +907,7 @@
>  		if (partial == chain)
>  			mark_inode_dirty(inode);
>  		else
> -			mark_buffer_dirty(partial->bh);
> +			mark_buffer_dirty_inode(partial->bh, inode);
>  		ext2_free_branches(inode, &nr, &nr+1, (chain+n-1) - partial);
>  	}
>  	/* Clear the ends of indirect blocks on the shared branch */
> @@ -916,7 +916,7 @@
>  				   partial->p + 1,
>  				   (u32*)partial->bh->b_data + addr_per_block,
>  				   (chain+n-1) - partial);
> -		mark_buffer_dirty(partial->bh);
> +		mark_buffer_dirty_inode(partial->bh, inode);
>  		if (IS_SYNC(inode)) {
>  			ll_rw_block (WRITE, 1, &partial->bh);
>  			wait_on_buffer (partial->bh);
> @@ -1208,7 +1208,7 @@
>  		raw_inode->i_block[0] = cpu_to_le32(kdev_t_to_nr(inode->i_rdev));
>  	else for (block = 0; block < EXT2_N_BLOCKS; block++)
>  		raw_inode->i_block[block] = inode->u.ext2_i.i_data[block];
> -	mark_buffer_dirty(bh);
> +	mark_buffer_dirty_inode(bh, inode);
>  	if (do_sync) {
>  		ll_rw_block (WRITE, 1, &bh);
>  		wait_on_buffer (bh);
> --- linux-2.4.0-test11/fs/ext2/namei.c.~1~	Tue Nov 21 15:40:22 2000
> +++ linux-2.4.0-test11/fs/ext2/namei.c	Tue Nov 21 16:01:15 2000
> @@ -296,7 +296,7 @@
>  			dir->u.ext2_i.i_flags &= ~EXT2_BTREE_FL;
>  			mark_inode_dirty(dir);
>  			dir->i_version = ++event;
> -			mark_buffer_dirty(bh);
> +			mark_buffer_dirty_inode(bh, dir);
>  			if (IS_SYNC(dir)) {
>  				ll_rw_block (WRITE, 1, &bh);
>  				wait_on_buffer (bh);
> @@ -337,7 +337,7 @@
>  			else
>  				de->inode = 0;
>  			dir->i_version = ++event;
> -			mark_buffer_dirty(bh);
> +			mark_buffer_dirty_inode(bh, dir);
>  			if (IS_SYNC(dir)) {
>  				ll_rw_block (WRITE, 1, &bh);
>  				wait_on_buffer (bh);
> @@ -449,7 +449,7 @@
>  	strcpy (de->name, "..");
>  	ext2_set_de_type(dir->i_sb, de, S_IFDIR);
>  	inode->i_nlink = 2;
> -	mark_buffer_dirty(dir_block);
> +	mark_buffer_dirty_inode(dir_block, dir);
>  	brelse (dir_block);
>  	inode->i_mode = S_IFDIR | mode;
>  	if (dir->i_mode & S_ISGID)
> @@ -755,7 +755,7 @@
>  					      EXT2_FEATURE_INCOMPAT_FILETYPE))
>  			new_de->file_type = old_de->file_type;
>  		new_dir->i_version = ++event;
> -		mark_buffer_dirty(new_bh);
> +		mark_buffer_dirty_inode(new_bh, new_dir);
>  		if (IS_SYNC(new_dir)) {
>  			ll_rw_block (WRITE, 1, &new_bh);
>  			wait_on_buffer (new_bh);
> @@ -786,7 +786,7 @@
>  	mark_inode_dirty(old_dir);
>  	if (dir_bh) {
>  		PARENT_INO(dir_bh->b_data) = le32_to_cpu(new_dir->i_ino);
> -		mark_buffer_dirty(dir_bh);
> +		mark_buffer_dirty_inode(dir_bh, old_inode);
>  		old_dir->i_nlink--;
>  		mark_inode_dirty(old_dir);
>  		if (new_inode) {
> --- linux-2.4.0-test11/include/linux/ext2_fs.h.~1~	Tue Nov 21 15:40:22 2000
> +++ linux-2.4.0-test11/include/linux/ext2_fs.h	Tue Nov 21 16:01:15 2000
> @@ -549,6 +549,7 @@
>  
>  /* fsync.c */
>  extern int ext2_sync_file (struct file *, struct dentry *, int);
> +extern int ext2_fsync_inode (struct inode *, int);
>  
>  /* ialloc.c */
>  extern struct inode * ext2_new_inode (const struct inode *, int, int *);
> --- linux-2.4.0-test11/mm/filemap.c.~1~	Tue Nov 21 15:47:48 2000
> +++ linux-2.4.0-test11/mm/filemap.c	Tue Nov 21 16:01:15 2000
> @@ -2521,8 +2521,14 @@
>  	if (cached_page)
>  		page_cache_free(cached_page);
>  
> +	/* For now, when the user asks for O_SYNC, we'll actually
> +	 * provide O_DSYNC. */
> +	if ((status >= 0) && (file->f_flags & O_SYNC))
> +		status = generic_osync_inode(inode, 1); /* 1 means datasync */
> +	
>  	err = written ? written : status;
>  out:
> +
>  	up(&inode->i_sem);
>  	return err;
>  fail_write:
> -
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