Fred Isaman | 9e69296 | 2011-07-30 20:52:41 -0400 | [diff] [blame] | 1 | /* |
| 2 | * linux/fs/nfs/blocklayout/blocklayout.h |
| 3 | * |
| 4 | * Module for the NFSv4.1 pNFS block layout driver. |
| 5 | * |
| 6 | * Copyright (c) 2006 The Regents of the University of Michigan. |
| 7 | * All rights reserved. |
| 8 | * |
| 9 | * Andy Adamson <andros@citi.umich.edu> |
| 10 | * Fred Isaman <iisaman@umich.edu> |
| 11 | * |
| 12 | * permission is granted to use, copy, create derivative works and |
| 13 | * redistribute this software and such derivative works for any purpose, |
| 14 | * so long as the name of the university of michigan is not used in |
| 15 | * any advertising or publicity pertaining to the use or distribution |
| 16 | * of this software without specific, written prior authorization. if |
| 17 | * the above copyright notice or any other identification of the |
| 18 | * university of michigan is included in any copy of any portion of |
| 19 | * this software, then the disclaimer below must also be included. |
| 20 | * |
| 21 | * this software is provided as is, without representation from the |
| 22 | * university of michigan as to its fitness for any purpose, and without |
| 23 | * warranty by the university of michigan of any kind, either express |
| 24 | * or implied, including without limitation the implied warranties of |
| 25 | * merchantability and fitness for a particular purpose. the regents |
| 26 | * of the university of michigan shall not be liable for any damages, |
| 27 | * including special, indirect, incidental, or consequential damages, |
| 28 | * with respect to any claim arising out or in connection with the use |
| 29 | * of the software, even if it has been or is hereafter advised of the |
| 30 | * possibility of such damages. |
| 31 | */ |
| 32 | |
| 33 | #include "blocklayout.h" |
| 34 | #define NFSDBG_FACILITY NFSDBG_PNFS_LD |
| 35 | |
| 36 | static void print_bl_extent(struct pnfs_block_extent *be) |
| 37 | { |
| 38 | dprintk("PRINT EXTENT extent %p\n", be); |
| 39 | if (be) { |
| 40 | dprintk(" be_f_offset %llu\n", (u64)be->be_f_offset); |
| 41 | dprintk(" be_length %llu\n", (u64)be->be_length); |
| 42 | dprintk(" be_v_offset %llu\n", (u64)be->be_v_offset); |
| 43 | dprintk(" be_state %d\n", be->be_state); |
| 44 | } |
| 45 | } |
| 46 | |
| 47 | static void |
| 48 | destroy_extent(struct kref *kref) |
| 49 | { |
| 50 | struct pnfs_block_extent *be; |
| 51 | |
| 52 | be = container_of(kref, struct pnfs_block_extent, be_refcnt); |
| 53 | dprintk("%s be=%p\n", __func__, be); |
| 54 | kfree(be); |
| 55 | } |
| 56 | |
| 57 | void |
| 58 | bl_put_extent(struct pnfs_block_extent *be) |
| 59 | { |
| 60 | if (be) { |
| 61 | dprintk("%s enter %p (%i)\n", __func__, be, |
| 62 | atomic_read(&be->be_refcnt.refcount)); |
| 63 | kref_put(&be->be_refcnt, destroy_extent); |
| 64 | } |
| 65 | } |
| 66 | |
| 67 | struct pnfs_block_extent *bl_alloc_extent(void) |
| 68 | { |
| 69 | struct pnfs_block_extent *be; |
| 70 | |
| 71 | be = kmalloc(sizeof(struct pnfs_block_extent), GFP_NOFS); |
| 72 | if (!be) |
| 73 | return NULL; |
| 74 | INIT_LIST_HEAD(&be->be_node); |
| 75 | kref_init(&be->be_refcnt); |
| 76 | be->be_inval = NULL; |
| 77 | return be; |
| 78 | } |
| 79 | |
| 80 | static void print_elist(struct list_head *list) |
| 81 | { |
| 82 | struct pnfs_block_extent *be; |
| 83 | dprintk("****************\n"); |
| 84 | dprintk("Extent list looks like:\n"); |
| 85 | list_for_each_entry(be, list, be_node) { |
| 86 | print_bl_extent(be); |
| 87 | } |
| 88 | dprintk("****************\n"); |
| 89 | } |
Fred Isaman | 03341d2 | 2011-07-30 20:52:45 -0400 | [diff] [blame^] | 90 | |
| 91 | static inline int |
| 92 | extents_consistent(struct pnfs_block_extent *old, struct pnfs_block_extent *new) |
| 93 | { |
| 94 | /* Note this assumes new->be_f_offset >= old->be_f_offset */ |
| 95 | return (new->be_state == old->be_state) && |
| 96 | ((new->be_state == PNFS_BLOCK_NONE_DATA) || |
| 97 | ((new->be_v_offset - old->be_v_offset == |
| 98 | new->be_f_offset - old->be_f_offset) && |
| 99 | new->be_mdev == old->be_mdev)); |
| 100 | } |
| 101 | |
| 102 | /* Adds new to appropriate list in bl, modifying new and removing existing |
| 103 | * extents as appropriate to deal with overlaps. |
| 104 | * |
| 105 | * See bl_find_get_extent for list constraints. |
| 106 | * |
| 107 | * Refcount on new is already set. If end up not using it, or error out, |
| 108 | * need to put the reference. |
| 109 | * |
| 110 | * bl->bl_ext_lock is held by caller. |
| 111 | */ |
| 112 | int |
| 113 | bl_add_merge_extent(struct pnfs_block_layout *bl, |
| 114 | struct pnfs_block_extent *new) |
| 115 | { |
| 116 | struct pnfs_block_extent *be, *tmp; |
| 117 | sector_t end = new->be_f_offset + new->be_length; |
| 118 | struct list_head *list; |
| 119 | |
| 120 | dprintk("%s enter with be=%p\n", __func__, new); |
| 121 | print_bl_extent(new); |
| 122 | list = &bl->bl_extents[bl_choose_list(new->be_state)]; |
| 123 | print_elist(list); |
| 124 | |
| 125 | /* Scan for proper place to insert, extending new to the left |
| 126 | * as much as possible. |
| 127 | */ |
| 128 | list_for_each_entry_safe(be, tmp, list, be_node) { |
| 129 | if (new->be_f_offset < be->be_f_offset) |
| 130 | break; |
| 131 | if (end <= be->be_f_offset + be->be_length) { |
| 132 | /* new is a subset of existing be*/ |
| 133 | if (extents_consistent(be, new)) { |
| 134 | dprintk("%s: new is subset, ignoring\n", |
| 135 | __func__); |
| 136 | bl_put_extent(new); |
| 137 | return 0; |
| 138 | } else |
| 139 | goto out_err; |
| 140 | } else if (new->be_f_offset <= |
| 141 | be->be_f_offset + be->be_length) { |
| 142 | /* new overlaps or abuts existing be */ |
| 143 | if (extents_consistent(be, new)) { |
| 144 | /* extend new to fully replace be */ |
| 145 | new->be_length += new->be_f_offset - |
| 146 | be->be_f_offset; |
| 147 | new->be_f_offset = be->be_f_offset; |
| 148 | new->be_v_offset = be->be_v_offset; |
| 149 | dprintk("%s: removing %p\n", __func__, be); |
| 150 | list_del(&be->be_node); |
| 151 | bl_put_extent(be); |
| 152 | } else if (new->be_f_offset != |
| 153 | be->be_f_offset + be->be_length) |
| 154 | goto out_err; |
| 155 | } |
| 156 | } |
| 157 | /* Note that if we never hit the above break, be will not point to a |
| 158 | * valid extent. However, in that case &be->be_node==list. |
| 159 | */ |
| 160 | list_add_tail(&new->be_node, &be->be_node); |
| 161 | dprintk("%s: inserting new\n", __func__); |
| 162 | print_elist(list); |
| 163 | /* Scan forward for overlaps. If we find any, extend new and |
| 164 | * remove the overlapped extent. |
| 165 | */ |
| 166 | be = list_prepare_entry(new, list, be_node); |
| 167 | list_for_each_entry_safe_continue(be, tmp, list, be_node) { |
| 168 | if (end < be->be_f_offset) |
| 169 | break; |
| 170 | /* new overlaps or abuts existing be */ |
| 171 | if (extents_consistent(be, new)) { |
| 172 | if (end < be->be_f_offset + be->be_length) { |
| 173 | /* extend new to fully cover be */ |
| 174 | end = be->be_f_offset + be->be_length; |
| 175 | new->be_length = end - new->be_f_offset; |
| 176 | } |
| 177 | dprintk("%s: removing %p\n", __func__, be); |
| 178 | list_del(&be->be_node); |
| 179 | bl_put_extent(be); |
| 180 | } else if (end != be->be_f_offset) { |
| 181 | list_del(&new->be_node); |
| 182 | goto out_err; |
| 183 | } |
| 184 | } |
| 185 | dprintk("%s: after merging\n", __func__); |
| 186 | print_elist(list); |
| 187 | /* FIXME - The per-list consistency checks have all been done, |
| 188 | * should now check cross-list consistency. |
| 189 | */ |
| 190 | return 0; |
| 191 | |
| 192 | out_err: |
| 193 | bl_put_extent(new); |
| 194 | return -EIO; |
| 195 | } |