diff options
| -rw-r--r-- | fs/nfs/blocklayout/blocklayout.h | 13 | ||||
| -rw-r--r-- | fs/nfs/blocklayout/extents.c | 106 |
2 files changed, 119 insertions, 0 deletions
diff --git a/fs/nfs/blocklayout/blocklayout.h b/fs/nfs/blocklayout/blocklayout.h index 3e05b08d534..581d8f47a72 100644 --- a/fs/nfs/blocklayout/blocklayout.h +++ b/fs/nfs/blocklayout/blocklayout.h @@ -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 */ diff --git a/fs/nfs/blocklayout/extents.c b/fs/nfs/blocklayout/extents.c index d0ca7604d33..ee4891f3249 100644 --- a/fs/nfs/blocklayout/extents.c +++ b/fs/nfs/blocklayout/extents.c @@ -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; +} |