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Re: [Cluster-devel] [GFS2 PATCH] GFS2: combine gfs2_alloc_block and gfs2_alloc_di



Hi,

On Wed, 2011-11-16 at 14:07 -0500, Bob Peterson wrote:
> ----- Original Message -----
> | It is not a good plan to rely on this to give us 0 and 1 inode
> | counts.
> | Using the ?: as before would be better. I suspect that if you
> | maintain
So the new patch is still doing bool to int conversions in various
places, I think.

> | separate counts of inodes (which can be 0 or 1 only) and other blocks
> | (any number) calculated at the start of the function then a number of
> | the tests you need to do will just become 0 or non-zero on one or
> | other
> | other of these.
> | 
> | Also, it would be a good plan to always pass the extent size in, even
> | if
> | the caller is requesting only a single block, then there is no need
> | for
> | a NULL test,
> | 
> | Steve.
> 
> Hi,
> 
> Okay, scratch that then. How about something like the following patch?
> 
> This patch moves more toward a generic multi-block allocator that
> takes a pointer to the number of data blocks to allocate, plus whether
> or not to allocate a dinode. In theory, it could be called to allocate
> (1) a single dinode block, (2) a group of one or more data blocks, or
> (3) a dinode plus several data blocks.
> 
> Regards,
> 
> Bob Peterson
> Red Hat File Systems
> --
>  fs/gfs2/bmap.c  |    4 +-
>  fs/gfs2/dir.c   |    2 +-
>  fs/gfs2/inode.c |    3 +-
>  fs/gfs2/rgrp.c  |   58 +++++++++++++++++++++++++++++-------------------------
>  fs/gfs2/rgrp.h  |    4 +-
>  fs/gfs2/xattr.c |    6 ++--
>  6 files changed, 41 insertions(+), 36 deletions(-)
> 
> diff --git a/fs/gfs2/bmap.c b/fs/gfs2/bmap.c
> index b69235b..cb74312 100644
> --- a/fs/gfs2/bmap.c
> +++ b/fs/gfs2/bmap.c
> @@ -133,7 +133,7 @@ int gfs2_unstuff_dinode(struct gfs2_inode *ip, struct page *page)
>  		   and write it out to disk */
>  
>  		unsigned int n = 1;
> -		error = gfs2_alloc_block(ip, &block, &n, 0, NULL);
> +		error = gfs2_alloc_blocks(ip, &block, &n, 0, NULL);
>  		if (error)
>  			goto out_brelse;
>  		if (isdir) {
> @@ -503,7 +503,7 @@ static int gfs2_bmap_alloc(struct inode *inode, const sector_t lblock,
>  	do {
>  		int error;
>  		n = blks - alloced;
> -		error = gfs2_alloc_block(ip, &bn, &n, 0, NULL);
> +		error = gfs2_alloc_blocks(ip, &bn, &n, 0, NULL);
>  		if (error)
>  			return error;
>  		alloced += n;
> diff --git a/fs/gfs2/dir.c b/fs/gfs2/dir.c
> index ae75319..f8485da 100644
> --- a/fs/gfs2/dir.c
> +++ b/fs/gfs2/dir.c
> @@ -823,7 +823,7 @@ static struct gfs2_leaf *new_leaf(struct inode *inode, struct buffer_head **pbh,
>  	struct gfs2_dirent *dent;
>  	struct qstr name = { .name = "", .len = 0, .hash = 0 };
>  
> -	error = gfs2_alloc_block(ip, &bn, &n, 0, NULL);
> +	error = gfs2_alloc_blocks(ip, &bn, &n, 0, NULL);
>  	if (error)
>  		return NULL;
>  	bh = gfs2_meta_new(ip->i_gl, bn);
> diff --git a/fs/gfs2/inode.c b/fs/gfs2/inode.c
> index de2668f..3ab192b 100644
> --- a/fs/gfs2/inode.c
> +++ b/fs/gfs2/inode.c
> @@ -389,6 +389,7 @@ static int alloc_dinode(struct gfs2_inode *dip, u64 *no_addr, u64 *generation)
>  {
>  	struct gfs2_sbd *sdp = GFS2_SB(&dip->i_inode);
>  	int error;
> +	int dblocks = 0;
>  
>  	if (gfs2_alloc_get(dip) == NULL)
>  		return -ENOMEM;
> @@ -402,7 +403,7 @@ static int alloc_dinode(struct gfs2_inode *dip, u64 *no_addr, u64 *generation)
>  	if (error)
>  		goto out_ipreserv;
>  
> -	error = gfs2_alloc_block(dip, no_addr, NULL, 1, generation);
> +	error = gfs2_alloc_blocks(dip, no_addr, &dblocks, 1, generation);
>  
>  	gfs2_trans_end(sdp);
>  
> diff --git a/fs/gfs2/rgrp.c b/fs/gfs2/rgrp.c
> index 995f4e6..131289b 100644
> --- a/fs/gfs2/rgrp.c
> +++ b/fs/gfs2/rgrp.c
> @@ -65,8 +65,8 @@ static const char valid_change[16] = {
>  };
>  
>  static u32 rgblk_search(struct gfs2_rgrpd *rgd, u32 goal,
> -                        unsigned char old_state, unsigned char new_state,
> -			unsigned int *n);
> +                        unsigned char old_state, bool dinode,
> +			unsigned int *ndata);
>  
>  /**
>   * gfs2_setbit - Set a bit in the bitmaps
> @@ -921,8 +921,7 @@ static void try_rgrp_unlink(struct gfs2_rgrpd *rgd, u64 *last_unlinked, u64 skip
>  	while (goal < rgd->rd_data) {
>  		down_write(&sdp->sd_log_flush_lock);
>  		n = 1;
> -		block = rgblk_search(rgd, goal, GFS2_BLKST_UNLINKED,
> -				     GFS2_BLKST_UNLINKED, &n);
> +		block = rgblk_search(rgd, goal, GFS2_BLKST_UNLINKED, 0, &n);
>  		up_write(&sdp->sd_log_flush_lock);
>  		if (block == BFITNOENT)
>  			break;
> @@ -1115,7 +1114,7 @@ static unsigned char gfs2_get_block_type(struct gfs2_rgrpd *rgd, u64 block)
>   * @rgd: the resource group descriptor
>   * @goal: the goal block within the RG (start here to search for avail block)
>   * @old_state: GFS2_BLKST_XXX the before-allocation state to find
> - * @new_state: GFS2_BLKST_XXX the after-allocation block state
> + * dinode: TRUE if the first block we allocate is for a dinode
>   * @n: The extent length
>   *
>   * Walk rgrp's bitmap to find bits that represent a block in @old_state.
> @@ -1132,8 +1131,7 @@ static unsigned char gfs2_get_block_type(struct gfs2_rgrpd *rgd, u64 block)
>   */
>  
>  static u32 rgblk_search(struct gfs2_rgrpd *rgd, u32 goal,
> -			unsigned char old_state, unsigned char new_state,
> -			unsigned int *n)
> +			unsigned char old_state, bool dinode, unsigned int *n)
>  {
>  	struct gfs2_bitmap *bi = NULL;
>  	const u32 length = rgd->rd_length;
> @@ -1141,7 +1139,14 @@ static u32 rgblk_search(struct gfs2_rgrpd *rgd, u32 goal,
>  	unsigned int buf, x;
>  	const unsigned int elen = *n;
>  	const u8 *buffer = NULL;
> +	unsigned char new_state;
>  
> +	if (old_state == GFS2_BLKST_UNLINKED)
> +		new_state = GFS2_BLKST_UNLINKED;
> +	else if (dinode)
> +		new_state = GFS2_BLKST_DINODE;
> +	else
> +		new_state = GFS2_BLKST_USED;

I know this vanishes in the next patch, but the code is a lot clearer
when it states explicitly what is being looked for and what changes are
going to be made.

>  	*n = 0;
>  	/* Find bitmap block that contains bits for goal block */
>  	for (buf = 0; buf < length; buf++) {
> @@ -1192,13 +1197,15 @@ skip:
>  	if (blk == BFITNOENT)
>  		return blk;
>  
> -	*n = 1;
>  	if (old_state == new_state)
>  		goto out;
>  
>  	gfs2_trans_add_bh(rgd->rd_gl, bi->bi_bh, 1);
>  	gfs2_setbit(rgd, bi->bi_bh->b_data, bi->bi_clone, bi->bi_offset,
>  		    bi, blk, new_state);
> +	if (new_state == GFS2_BLKST_USED)
> +		*n = 1;
> +	new_state = GFS2_BLKST_USED; /* for extents, we need data blocks */
If the extent length includes the inode, then we don't need to special
case this.

>  	goal = blk;
>  	while (*n < elen) {
>  		goal++;
> @@ -1300,18 +1307,18 @@ static void gfs2_rgrp_error(struct gfs2_rgrpd *rgd)
>  }
>  
>  /**
> - * gfs2_alloc_block - Allocate one or more blocks
> + * gfs2_alloc_blocks - Allocate one or more blocks of data and/or a dinode
>   * @ip: the inode to allocate the block for
>   * @bn: Used to return the starting block number
> - * @n: requested number of blocks/extent length (value/result)
> - * dinode: 1 if we're allocating a dinode, 0 if it's a data block
> + * @ndata: requested number of data blocks/extent length (value/result)
> + * dinode: 1 if we're allocating a dinode block, else 0
A missing @

>   * @generation: the generation number of the inode
>   *
>   * Returns: 0 or error
>   */
>  
> -int gfs2_alloc_block(struct gfs2_inode *ip, u64 *bn, unsigned int *n,
> -		     int dinode, u64 *generation)
> +int gfs2_alloc_blocks(struct gfs2_inode *ip, u64 *bn, unsigned int *ndata,
> +		      bool dinode, u64 *generation)
>  {
>  	struct gfs2_sbd *sdp = GFS2_SB(&ip->i_inode);
>  	struct buffer_head *dibh;
> @@ -1319,9 +1326,7 @@ int gfs2_alloc_block(struct gfs2_inode *ip, u64 *bn, unsigned int *n,
>  	struct gfs2_rgrpd *rgd;
>  	u32 goal, blk; /* block, within the rgrp scope */
>  	u64 block; /* block, within the file system scope */
> -	unsigned int extn = 1;
>  	int error;
> -	unsigned char blk_type = dinode ? GFS2_BLKST_DINODE : GFS2_BLKST_USED;
>  
>  	/* Only happens if there is a bug in gfs2, return something distinctive
>  	 * to ensure that it is noticed.
> @@ -1329,8 +1334,6 @@ int gfs2_alloc_block(struct gfs2_inode *ip, u64 *bn, unsigned int *n,
>  	if (al == NULL)
>  		return -ECANCELED;
>  
> -	if (n == NULL)
> -		n = &extn;
>  	rgd = ip->i_rgd;
>  
>  	if (!dinode && rgrp_contains_block(rgd, ip->i_goal))
> @@ -1338,7 +1341,7 @@ int gfs2_alloc_block(struct gfs2_inode *ip, u64 *bn, unsigned int *n,
>  	else
>  		goal = rgd->rd_last_alloc;
>  
> -	blk = rgblk_search(rgd, goal, GFS2_BLKST_FREE, blk_type, n);
> +	blk = rgblk_search(rgd, goal, GFS2_BLKST_FREE, dinode, ndata);
>  
>  	/* Since all blocks are reserved in advance, this shouldn't happen */
>  	if (blk == BFITNOENT)
> @@ -1347,7 +1350,7 @@ int gfs2_alloc_block(struct gfs2_inode *ip, u64 *bn, unsigned int *n,
>  	rgd->rd_last_alloc = blk;
>  	block = rgd->rd_data0 + blk;
>  	if (!dinode) {
> -		ip->i_goal = block + *n - 1;
> +		ip->i_goal = block + *ndata - 1;
>  		error = gfs2_meta_inode_buffer(ip, &dibh);
>  		if (error == 0) {
>  			struct gfs2_dinode *di =
> @@ -1358,11 +1361,12 @@ int gfs2_alloc_block(struct gfs2_inode *ip, u64 *bn, unsigned int *n,
>  			brelse(dibh);
>  		}
>  	}
> -	if (rgd->rd_free < *n)
> +	if (rgd->rd_free < (*ndata) + dinode)

This (*ndata) + dinode expression appears a lot, can we just have an
extent length variable, so it doesn't have to be calculated separately
each time?

>  		goto rgrp_error;
>  
> -	rgd->rd_free -= *n;
> +	rgd->rd_free -= *ndata;
>  	if (dinode) {
> +		rgd->rd_free--;
>  		rgd->rd_dinodes++;
>  		*generation = rgd->rd_igeneration++;
>  		if (*generation == 0)
> @@ -1372,17 +1376,17 @@ int gfs2_alloc_block(struct gfs2_inode *ip, u64 *bn, unsigned int *n,
>  	gfs2_trans_add_bh(rgd->rd_gl, rgd->rd_bits[0].bi_bh, 1);
>  	gfs2_rgrp_out(rgd, rgd->rd_bits[0].bi_bh->b_data);
>  
> -	al->al_alloced += *n;
> +	al->al_alloced += (*ndata) + dinode;
>  
> -	gfs2_statfs_change(sdp, 0, -(s64)*n, dinode ? 1 : 0);
> +	gfs2_statfs_change(sdp, 0, (-(s64)((*ndata) + dinode)), dinode);
>  	if (dinode)
>  		gfs2_trans_add_unrevoke(sdp, block, 1);
> -	else
> -		gfs2_quota_change(ip, *n, ip->i_inode.i_uid,
> +	if (*ndata)
> +		gfs2_quota_change(ip, *ndata, ip->i_inode.i_uid,
>  				  ip->i_inode.i_gid);
>  
Looks like we need to take a look at the inode allocation and see why we
don't do the quota change for that via this function. That can be a
separate patch though.

> -	rgd->rd_free_clone -= *n;
> -	trace_gfs2_block_alloc(ip, block, *n, blk_type);
> +	rgd->rd_free_clone -= (*ndata) + dinode;
> +	trace_gfs2_block_alloc(ip, block, *ndata, dinode);
The call to the tracepoint is wrong, the final argument is supposed to
be the type of the block that is being changed. That makes it a bit
awkward in terms of tracing with the combined functions :( Maybe resolve
this in the splitting rgblk_search patch, where it might be possible to
move the tracing to the gfs2_alloc_extent() function.

Otherwise, it looks good,

Steve.

>  	*bn = block;
>  	return 0;
>  
> diff --git a/fs/gfs2/rgrp.h b/fs/gfs2/rgrp.h
> index 4cb5608..b3b61b8 100644
> --- a/fs/gfs2/rgrp.h
> +++ b/fs/gfs2/rgrp.h
> @@ -39,8 +39,8 @@ static inline void gfs2_alloc_put(struct gfs2_inode *ip)
>  extern int gfs2_inplace_reserve(struct gfs2_inode *ip);
>  extern void gfs2_inplace_release(struct gfs2_inode *ip);
>  
> -extern int gfs2_alloc_block(struct gfs2_inode *ip, u64 *bn, unsigned int *n,
> -			    int dinode, u64 *generation);
> +extern int gfs2_alloc_blocks(struct gfs2_inode *ip, u64 *bn, unsigned int *n,
> +			     bool dinode, u64 *generation);
>  
>  extern void __gfs2_free_blocks(struct gfs2_inode *ip, u64 bstart, u32 blen, int meta);
>  extern void gfs2_free_meta(struct gfs2_inode *ip, u64 bstart, u32 blen);
> diff --git a/fs/gfs2/xattr.c b/fs/gfs2/xattr.c
> index e4794a5..ef74e159 100644
> --- a/fs/gfs2/xattr.c
> +++ b/fs/gfs2/xattr.c
> @@ -610,7 +610,7 @@ static int ea_alloc_blk(struct gfs2_inode *ip, struct buffer_head **bhp)
>  	u64 block;
>  	int error;
>  
> -	error = gfs2_alloc_block(ip, &block, &n, 0, NULL);
> +	error = gfs2_alloc_blocks(ip, &block, &n, 0, NULL);
>  	if (error)
>  		return error;
>  	gfs2_trans_add_unrevoke(sdp, block, 1);
> @@ -672,7 +672,7 @@ static int ea_write(struct gfs2_inode *ip, struct gfs2_ea_header *ea,
>  			int mh_size = sizeof(struct gfs2_meta_header);
>  			unsigned int n = 1;
>  
> -			error = gfs2_alloc_block(ip, &block, &n, 0, NULL);
> +			error = gfs2_alloc_blocks(ip, &block, &n, 0, NULL);
>  			if (error)
>  				return error;
>  			gfs2_trans_add_unrevoke(sdp, block, 1);
> @@ -992,7 +992,7 @@ static int ea_set_block(struct gfs2_inode *ip, struct gfs2_ea_request *er,
>  	} else {
>  		u64 blk;
>  		unsigned int n = 1;
> -		error = gfs2_alloc_block(ip, &blk, &n, 0, NULL);
> +		error = gfs2_alloc_blocks(ip, &blk, &n, 0, NULL);
>  		if (error)
>  			return error;
>  		gfs2_trans_add_unrevoke(sdp, blk, 1);



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