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Commit 03341d2c authored by Fred Isaman's avatar Fred Isaman Committed by Trond Myklebust
Browse files

pnfsblock: merge extents 



Replace a stub, so that extents underlying the layouts are properly
added, merged, or ignored as necessary.

Signed-off-by: default avatarFred Isaman <iisaman@citi.umich.edu>
[pnfsblock: delete the new node before put it]
Signed-off-by: default avatarMingyang Guo <guomingyang@nrchpc.ac.cn>
Signed-off-by: default avatarBenny Halevy <bhalevy@panasas.com>
Signed-off-by: default avatarPeng Tao <peng_tao@emc.com>
Signed-off-by: default avatarBenny Halevy <bhalevy@tonian.com>
Signed-off-by: default avatarJim Rees <rees@umich.edu>
Signed-off-by: default avatarTrond Myklebust <Trond.Myklebust@netapp.com>
parent a60d2ebd

fs/nfs/blocklayout/blocklayout.h

+13 −0
Original line number Diff line number Diff line
@@ -80,6 +80,14 @@ enum extentclass4 { 
	EXTENT_LISTS    = 2,

};



static inline int bl_choose_list(enum exstate4 state)

{

	if (state == PNFS_BLOCK_READ_DATA || state == PNFS_BLOCK_NONE_DATA)

		return RO_EXTENT;

	else

		return RW_EXTENT;

}



struct pnfs_block_layout {

	struct pnfs_layout_hdr bl_layout;

	struct pnfs_inval_markings bl_inval; /* tracks INVAL->RW transition */
@@ -137,5 +145,10 @@ int nfs4_blk_process_layoutget(struct pnfs_layout_hdr *lo, 
/* blocklayoutdm.c */

void bl_free_block_dev(struct pnfs_block_dev *bdev);



/* extents.c */

void bl_put_extent(struct pnfs_block_extent *be);

struct pnfs_block_extent *bl_alloc_extent(void);

int bl_add_merge_extent(struct pnfs_block_layout *bl,

			 struct pnfs_block_extent *new);



#endif /* FS_NFS_NFS4BLOCKLAYOUT_H */

fs/nfs/blocklayout/extents.c

+106 −0
Original line number Diff line number Diff line
@@ -87,3 +87,109 @@ static void print_elist(struct list_head *list) 
	}

	dprintk("****************\n");

}



static inline int

extents_consistent(struct pnfs_block_extent *old, struct pnfs_block_extent *new)

{

	/* Note this assumes new->be_f_offset >= old->be_f_offset */

	return (new->be_state == old->be_state) &&

		((new->be_state == PNFS_BLOCK_NONE_DATA) ||

		 ((new->be_v_offset - old->be_v_offset ==

		   new->be_f_offset - old->be_f_offset) &&

		  new->be_mdev == old->be_mdev));

}



/* Adds new to appropriate list in bl, modifying new and removing existing

 * extents as appropriate to deal with overlaps.

 *

 * See bl_find_get_extent for list constraints.

 *

 * Refcount on new is already set.  If end up not using it, or error out,

 * need to put the reference.

 *

 * bl->bl_ext_lock is held by caller.

 */

int

bl_add_merge_extent(struct pnfs_block_layout *bl,

		     struct pnfs_block_extent *new)

{

	struct pnfs_block_extent *be, *tmp;

	sector_t end = new->be_f_offset + new->be_length;

	struct list_head *list;



	dprintk("%s enter with be=%p\n", __func__, new);

	print_bl_extent(new);

	list = &bl->bl_extents[bl_choose_list(new->be_state)];

	print_elist(list);



	/* Scan for proper place to insert, extending new to the left

	 * as much as possible.

	 */

	list_for_each_entry_safe(be, tmp, list, be_node) {

		if (new->be_f_offset < be->be_f_offset)

			break;

		if (end <= be->be_f_offset + be->be_length) {

			/* new is a subset of existing be*/

			if (extents_consistent(be, new)) {

				dprintk("%s: new is subset, ignoring\n",

					__func__);

				bl_put_extent(new);

				return 0;

			} else

				goto out_err;

		} else if (new->be_f_offset <=

				be->be_f_offset + be->be_length) {

			/* new overlaps or abuts existing be */

			if (extents_consistent(be, new)) {

				/* extend new to fully replace be */

				new->be_length += new->be_f_offset -

						  be->be_f_offset;

				new->be_f_offset = be->be_f_offset;

				new->be_v_offset = be->be_v_offset;

				dprintk("%s: removing %p\n", __func__, be);

				list_del(&be->be_node);

				bl_put_extent(be);

			} else if (new->be_f_offset !=

				   be->be_f_offset + be->be_length)

				goto out_err;

		}

	}

	/* Note that if we never hit the above break, be will not point to a

	 * valid extent.  However, in that case &be->be_node==list.

	 */

	list_add_tail(&new->be_node, &be->be_node);

	dprintk("%s: inserting new\n", __func__);

	print_elist(list);

	/* Scan forward for overlaps.  If we find any, extend new and

	 * remove the overlapped extent.

	 */

	be = list_prepare_entry(new, list, be_node);

	list_for_each_entry_safe_continue(be, tmp, list, be_node) {

		if (end < be->be_f_offset)

			break;

		/* new overlaps or abuts existing be */

		if (extents_consistent(be, new)) {

			if (end < be->be_f_offset + be->be_length) {

				/* extend new to fully cover be */

				end = be->be_f_offset + be->be_length;

				new->be_length = end - new->be_f_offset;

			}

			dprintk("%s: removing %p\n", __func__, be);

			list_del(&be->be_node);

			bl_put_extent(be);

		} else if (end != be->be_f_offset) {

			list_del(&new->be_node);

			goto out_err;

		}

	}

	dprintk("%s: after merging\n", __func__);

	print_elist(list);

	/* FIXME - The per-list consistency checks have all been done,

	 * should now check cross-list consistency.

	 */

	return 0;



 out_err:

	bl_put_extent(new);

	return -EIO;

}