From 9f3770422c771da32c1d14e650c695eec27dbd1d Mon Sep 17 00:00:00 2001 From: Fred Isaman Date: Sat, 30 Jul 2011 20:52:50 -0400 Subject: pnfsblock: merge rw extents Signed-off-by: Fred Isaman Signed-off-by: Benny Halevy Signed-off-by: Benny Halevy Signed-off-by: Jim Rees Signed-off-by: Trond Myklebust --- fs/nfs/blocklayout/extents.c | 47 ++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 47 insertions(+) (limited to 'fs/nfs/blocklayout/extents.c') diff --git a/fs/nfs/blocklayout/extents.c b/fs/nfs/blocklayout/extents.c index 473faee9cde..292aadfd4d4 100644 --- a/fs/nfs/blocklayout/extents.c +++ b/fs/nfs/blocklayout/extents.c @@ -493,3 +493,50 @@ bl_find_get_extent(struct pnfs_block_layout *bl, sector_t isect, print_bl_extent(ret); return ret; } + +/* Helper function to set_to_rw that initialize a new extent */ +static void +_prep_new_extent(struct pnfs_block_extent *new, + struct pnfs_block_extent *orig, + sector_t offset, sector_t length, int state) +{ + kref_init(&new->be_refcnt); + /* don't need to INIT_LIST_HEAD(&new->be_node) */ + memcpy(&new->be_devid, &orig->be_devid, sizeof(struct nfs4_deviceid)); + new->be_mdev = orig->be_mdev; + new->be_f_offset = offset; + new->be_length = length; + new->be_v_offset = orig->be_v_offset - orig->be_f_offset + offset; + new->be_state = state; + new->be_inval = orig->be_inval; +} + +/* Tries to merge be with extent in front of it in list. + * Frees storage if not used. + */ +static struct pnfs_block_extent * +_front_merge(struct pnfs_block_extent *be, struct list_head *head, + struct pnfs_block_extent *storage) +{ + struct pnfs_block_extent *prev; + + if (!storage) + goto no_merge; + if (&be->be_node == head || be->be_node.prev == head) + goto no_merge; + prev = list_entry(be->be_node.prev, struct pnfs_block_extent, be_node); + if ((prev->be_f_offset + prev->be_length != be->be_f_offset) || + !extents_consistent(prev, be)) + goto no_merge; + _prep_new_extent(storage, prev, prev->be_f_offset, + prev->be_length + be->be_length, prev->be_state); + list_replace(&prev->be_node, &storage->be_node); + bl_put_extent(prev); + list_del(&be->be_node); + bl_put_extent(be); + return storage; + + no_merge: + kfree(storage); + return be; +} -- cgit v1.2.3