Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1 | /* |
| 2 | * fs/fs-writeback.c |
| 3 | * |
| 4 | * Copyright (C) 2002, Linus Torvalds. |
| 5 | * |
| 6 | * Contains all the functions related to writing back and waiting |
| 7 | * upon dirty inodes against superblocks, and writing back dirty |
| 8 | * pages against inodes. ie: data writeback. Writeout of the |
| 9 | * inode itself is not handled here. |
| 10 | * |
Francois Cami | e1f8e87 | 2008-10-15 22:01:59 -0700 | [diff] [blame] | 11 | * 10Apr2002 Andrew Morton |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 12 | * Split out of fs/inode.c |
| 13 | * Additions for address_space-based writeback |
| 14 | */ |
| 15 | |
| 16 | #include <linux/kernel.h> |
Jens Axboe | f5ff842 | 2007-09-21 09:19:54 +0200 | [diff] [blame] | 17 | #include <linux/module.h> |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 18 | #include <linux/spinlock.h> |
| 19 | #include <linux/sched.h> |
| 20 | #include <linux/fs.h> |
| 21 | #include <linux/mm.h> |
Jens Axboe | 03ba378 | 2009-09-09 09:08:54 +0200 | [diff] [blame] | 22 | #include <linux/kthread.h> |
| 23 | #include <linux/freezer.h> |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 24 | #include <linux/writeback.h> |
| 25 | #include <linux/blkdev.h> |
| 26 | #include <linux/backing-dev.h> |
| 27 | #include <linux/buffer_head.h> |
David Howells | 07f3f05c | 2006-09-30 20:52:18 +0200 | [diff] [blame] | 28 | #include "internal.h" |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 29 | |
Jens Axboe | 66f3b8e | 2009-09-02 09:19:46 +0200 | [diff] [blame] | 30 | #define inode_to_bdi(inode) ((inode)->i_mapping->backing_dev_info) |
Adrian Bunk | f11b00f | 2008-04-29 00:58:56 -0700 | [diff] [blame] | 31 | |
Jens Axboe | 03ba378 | 2009-09-09 09:08:54 +0200 | [diff] [blame] | 32 | /* |
Jens Axboe | d0bceac | 2009-05-18 08:20:32 +0200 | [diff] [blame] | 33 | * We don't actually have pdflush, but this one is exported though /proc... |
| 34 | */ |
| 35 | int nr_pdflush_threads; |
| 36 | |
| 37 | /* |
Jens Axboe | c4a77a6 | 2009-09-16 15:18:25 +0200 | [diff] [blame] | 38 | * Passed into wb_writeback(), essentially a subset of writeback_control |
| 39 | */ |
| 40 | struct wb_writeback_args { |
| 41 | long nr_pages; |
| 42 | struct super_block *sb; |
| 43 | enum writeback_sync_modes sync_mode; |
Wu Fengguang | d3ddec7 | 2009-09-23 20:33:40 +0800 | [diff] [blame] | 44 | int for_kupdate:1; |
| 45 | int range_cyclic:1; |
| 46 | int for_background:1; |
Jens Axboe | c4a77a6 | 2009-09-16 15:18:25 +0200 | [diff] [blame] | 47 | }; |
| 48 | |
| 49 | /* |
Jens Axboe | 03ba378 | 2009-09-09 09:08:54 +0200 | [diff] [blame] | 50 | * Work items for the bdi_writeback threads |
Adrian Bunk | f11b00f | 2008-04-29 00:58:56 -0700 | [diff] [blame] | 51 | */ |
Jens Axboe | 03ba378 | 2009-09-09 09:08:54 +0200 | [diff] [blame] | 52 | struct bdi_work { |
Jens Axboe | 8010c3b | 2009-09-15 20:04:57 +0200 | [diff] [blame] | 53 | struct list_head list; /* pending work list */ |
| 54 | struct rcu_head rcu_head; /* for RCU free/clear of work */ |
Jens Axboe | 03ba378 | 2009-09-09 09:08:54 +0200 | [diff] [blame] | 55 | |
Jens Axboe | 8010c3b | 2009-09-15 20:04:57 +0200 | [diff] [blame] | 56 | unsigned long seen; /* threads that have seen this work */ |
| 57 | atomic_t pending; /* number of threads still to do work */ |
Jens Axboe | 03ba378 | 2009-09-09 09:08:54 +0200 | [diff] [blame] | 58 | |
Jens Axboe | 8010c3b | 2009-09-15 20:04:57 +0200 | [diff] [blame] | 59 | struct wb_writeback_args args; /* writeback arguments */ |
Jens Axboe | 03ba378 | 2009-09-09 09:08:54 +0200 | [diff] [blame] | 60 | |
Jens Axboe | 8010c3b | 2009-09-15 20:04:57 +0200 | [diff] [blame] | 61 | unsigned long state; /* flag bits, see WS_* */ |
Jens Axboe | 03ba378 | 2009-09-09 09:08:54 +0200 | [diff] [blame] | 62 | }; |
| 63 | |
| 64 | enum { |
| 65 | WS_USED_B = 0, |
| 66 | WS_ONSTACK_B, |
| 67 | }; |
| 68 | |
| 69 | #define WS_USED (1 << WS_USED_B) |
| 70 | #define WS_ONSTACK (1 << WS_ONSTACK_B) |
| 71 | |
| 72 | static inline bool bdi_work_on_stack(struct bdi_work *work) |
Adrian Bunk | f11b00f | 2008-04-29 00:58:56 -0700 | [diff] [blame] | 73 | { |
Jens Axboe | 03ba378 | 2009-09-09 09:08:54 +0200 | [diff] [blame] | 74 | return test_bit(WS_ONSTACK_B, &work->state); |
| 75 | } |
| 76 | |
| 77 | static inline void bdi_work_init(struct bdi_work *work, |
Jens Axboe | b6e5131 | 2009-09-16 15:13:54 +0200 | [diff] [blame] | 78 | struct wb_writeback_args *args) |
Jens Axboe | 03ba378 | 2009-09-09 09:08:54 +0200 | [diff] [blame] | 79 | { |
| 80 | INIT_RCU_HEAD(&work->rcu_head); |
Jens Axboe | b6e5131 | 2009-09-16 15:13:54 +0200 | [diff] [blame] | 81 | work->args = *args; |
Jens Axboe | 03ba378 | 2009-09-09 09:08:54 +0200 | [diff] [blame] | 82 | work->state = WS_USED; |
| 83 | } |
| 84 | |
Adrian Bunk | f11b00f | 2008-04-29 00:58:56 -0700 | [diff] [blame] | 85 | /** |
| 86 | * writeback_in_progress - determine whether there is writeback in progress |
| 87 | * @bdi: the device's backing_dev_info structure. |
| 88 | * |
Jens Axboe | 03ba378 | 2009-09-09 09:08:54 +0200 | [diff] [blame] | 89 | * Determine whether there is writeback waiting to be handled against a |
| 90 | * backing device. |
Adrian Bunk | f11b00f | 2008-04-29 00:58:56 -0700 | [diff] [blame] | 91 | */ |
| 92 | int writeback_in_progress(struct backing_dev_info *bdi) |
| 93 | { |
Jens Axboe | 03ba378 | 2009-09-09 09:08:54 +0200 | [diff] [blame] | 94 | return !list_empty(&bdi->work_list); |
Adrian Bunk | f11b00f | 2008-04-29 00:58:56 -0700 | [diff] [blame] | 95 | } |
| 96 | |
Jens Axboe | 03ba378 | 2009-09-09 09:08:54 +0200 | [diff] [blame] | 97 | static void bdi_work_clear(struct bdi_work *work) |
Adrian Bunk | f11b00f | 2008-04-29 00:58:56 -0700 | [diff] [blame] | 98 | { |
Jens Axboe | 03ba378 | 2009-09-09 09:08:54 +0200 | [diff] [blame] | 99 | clear_bit(WS_USED_B, &work->state); |
| 100 | smp_mb__after_clear_bit(); |
Nick Piggin | 1ef7d9a | 2009-09-15 21:37:55 +0200 | [diff] [blame] | 101 | /* |
| 102 | * work can have disappeared at this point. bit waitq functions |
| 103 | * should be able to tolerate this, provided bdi_sched_wait does |
| 104 | * not dereference it's pointer argument. |
| 105 | */ |
Jens Axboe | 03ba378 | 2009-09-09 09:08:54 +0200 | [diff] [blame] | 106 | wake_up_bit(&work->state, WS_USED_B); |
Adrian Bunk | f11b00f | 2008-04-29 00:58:56 -0700 | [diff] [blame] | 107 | } |
| 108 | |
Jens Axboe | 03ba378 | 2009-09-09 09:08:54 +0200 | [diff] [blame] | 109 | static void bdi_work_free(struct rcu_head *head) |
Nick Piggin | 4195f73 | 2009-05-28 09:01:15 +0200 | [diff] [blame] | 110 | { |
Jens Axboe | 03ba378 | 2009-09-09 09:08:54 +0200 | [diff] [blame] | 111 | struct bdi_work *work = container_of(head, struct bdi_work, rcu_head); |
Nick Piggin | 4195f73 | 2009-05-28 09:01:15 +0200 | [diff] [blame] | 112 | |
Jens Axboe | 03ba378 | 2009-09-09 09:08:54 +0200 | [diff] [blame] | 113 | if (!bdi_work_on_stack(work)) |
| 114 | kfree(work); |
| 115 | else |
| 116 | bdi_work_clear(work); |
| 117 | } |
| 118 | |
| 119 | static void wb_work_complete(struct bdi_work *work) |
| 120 | { |
Jens Axboe | c4a77a6 | 2009-09-16 15:18:25 +0200 | [diff] [blame] | 121 | const enum writeback_sync_modes sync_mode = work->args.sync_mode; |
Nick Piggin | 77b9d05 | 2009-09-15 21:34:51 +0200 | [diff] [blame] | 122 | int onstack = bdi_work_on_stack(work); |
Jens Axboe | 03ba378 | 2009-09-09 09:08:54 +0200 | [diff] [blame] | 123 | |
| 124 | /* |
| 125 | * For allocated work, we can clear the done/seen bit right here. |
| 126 | * For on-stack work, we need to postpone both the clear and free |
| 127 | * to after the RCU grace period, since the stack could be invalidated |
| 128 | * as soon as bdi_work_clear() has done the wakeup. |
| 129 | */ |
Nick Piggin | 77b9d05 | 2009-09-15 21:34:51 +0200 | [diff] [blame] | 130 | if (!onstack) |
Jens Axboe | 03ba378 | 2009-09-09 09:08:54 +0200 | [diff] [blame] | 131 | bdi_work_clear(work); |
Nick Piggin | 77b9d05 | 2009-09-15 21:34:51 +0200 | [diff] [blame] | 132 | if (sync_mode == WB_SYNC_NONE || onstack) |
Jens Axboe | 03ba378 | 2009-09-09 09:08:54 +0200 | [diff] [blame] | 133 | call_rcu(&work->rcu_head, bdi_work_free); |
| 134 | } |
| 135 | |
| 136 | static void wb_clear_pending(struct bdi_writeback *wb, struct bdi_work *work) |
| 137 | { |
| 138 | /* |
| 139 | * The caller has retrieved the work arguments from this work, |
| 140 | * drop our reference. If this is the last ref, delete and free it |
| 141 | */ |
| 142 | if (atomic_dec_and_test(&work->pending)) { |
| 143 | struct backing_dev_info *bdi = wb->bdi; |
| 144 | |
| 145 | spin_lock(&bdi->wb_lock); |
| 146 | list_del_rcu(&work->list); |
| 147 | spin_unlock(&bdi->wb_lock); |
| 148 | |
| 149 | wb_work_complete(work); |
Nick Piggin | 4195f73 | 2009-05-28 09:01:15 +0200 | [diff] [blame] | 150 | } |
| 151 | } |
| 152 | |
Jens Axboe | 03ba378 | 2009-09-09 09:08:54 +0200 | [diff] [blame] | 153 | static void bdi_queue_work(struct backing_dev_info *bdi, struct bdi_work *work) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 154 | { |
Jens Axboe | bcddc3f | 2009-09-13 20:07:36 +0200 | [diff] [blame] | 155 | work->seen = bdi->wb_mask; |
| 156 | BUG_ON(!work->seen); |
| 157 | atomic_set(&work->pending, bdi->wb_cnt); |
| 158 | BUG_ON(!bdi->wb_cnt); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 159 | |
Jens Axboe | bcddc3f | 2009-09-13 20:07:36 +0200 | [diff] [blame] | 160 | /* |
Nick Piggin | deed62e | 2009-09-15 21:32:58 +0200 | [diff] [blame] | 161 | * list_add_tail_rcu() contains the necessary barriers to |
| 162 | * make sure the above stores are seen before the item is |
| 163 | * noticed on the list |
Jens Axboe | bcddc3f | 2009-09-13 20:07:36 +0200 | [diff] [blame] | 164 | */ |
Jens Axboe | bcddc3f | 2009-09-13 20:07:36 +0200 | [diff] [blame] | 165 | spin_lock(&bdi->wb_lock); |
| 166 | list_add_tail_rcu(&work->list, &bdi->work_list); |
| 167 | spin_unlock(&bdi->wb_lock); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 168 | |
| 169 | /* |
Jens Axboe | 03ba378 | 2009-09-09 09:08:54 +0200 | [diff] [blame] | 170 | * If the default thread isn't there, make sure we add it. When |
| 171 | * it gets created and wakes up, we'll run this work. |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 172 | */ |
Jens Axboe | 03ba378 | 2009-09-09 09:08:54 +0200 | [diff] [blame] | 173 | if (unlikely(list_empty_careful(&bdi->wb_list))) |
| 174 | wake_up_process(default_backing_dev_info.wb.task); |
| 175 | else { |
| 176 | struct bdi_writeback *wb = &bdi->wb; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 177 | |
Nick Piggin | 1ef7d9a | 2009-09-15 21:37:55 +0200 | [diff] [blame] | 178 | if (wb->task) |
Jens Axboe | 03ba378 | 2009-09-09 09:08:54 +0200 | [diff] [blame] | 179 | wake_up_process(wb->task); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 180 | } |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 181 | } |
| 182 | |
Jens Axboe | 03ba378 | 2009-09-09 09:08:54 +0200 | [diff] [blame] | 183 | /* |
| 184 | * Used for on-stack allocated work items. The caller needs to wait until |
| 185 | * the wb threads have acked the work before it's safe to continue. |
| 186 | */ |
| 187 | static void bdi_wait_on_work_clear(struct bdi_work *work) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 188 | { |
Jens Axboe | 03ba378 | 2009-09-09 09:08:54 +0200 | [diff] [blame] | 189 | wait_on_bit(&work->state, WS_USED_B, bdi_sched_wait, |
| 190 | TASK_UNINTERRUPTIBLE); |
| 191 | } |
| 192 | |
Jens Axboe | f11fcae | 2009-09-15 09:53:35 +0200 | [diff] [blame] | 193 | static void bdi_alloc_queue_work(struct backing_dev_info *bdi, |
Jens Axboe | b6e5131 | 2009-09-16 15:13:54 +0200 | [diff] [blame] | 194 | struct wb_writeback_args *args) |
Jens Axboe | 03ba378 | 2009-09-09 09:08:54 +0200 | [diff] [blame] | 195 | { |
| 196 | struct bdi_work *work; |
| 197 | |
Jens Axboe | bcddc3f | 2009-09-13 20:07:36 +0200 | [diff] [blame] | 198 | /* |
| 199 | * This is WB_SYNC_NONE writeback, so if allocation fails just |
| 200 | * wakeup the thread for old dirty data writeback |
| 201 | */ |
Jens Axboe | 03ba378 | 2009-09-09 09:08:54 +0200 | [diff] [blame] | 202 | work = kmalloc(sizeof(*work), GFP_ATOMIC); |
Jens Axboe | bcddc3f | 2009-09-13 20:07:36 +0200 | [diff] [blame] | 203 | if (work) { |
Jens Axboe | b6e5131 | 2009-09-16 15:13:54 +0200 | [diff] [blame] | 204 | bdi_work_init(work, args); |
Jens Axboe | bcddc3f | 2009-09-13 20:07:36 +0200 | [diff] [blame] | 205 | bdi_queue_work(bdi, work); |
| 206 | } else { |
| 207 | struct bdi_writeback *wb = &bdi->wb; |
Jens Axboe | 03ba378 | 2009-09-09 09:08:54 +0200 | [diff] [blame] | 208 | |
Jens Axboe | bcddc3f | 2009-09-13 20:07:36 +0200 | [diff] [blame] | 209 | if (wb->task) |
| 210 | wake_up_process(wb->task); |
| 211 | } |
Jens Axboe | 03ba378 | 2009-09-09 09:08:54 +0200 | [diff] [blame] | 212 | } |
| 213 | |
Jens Axboe | b6e5131 | 2009-09-16 15:13:54 +0200 | [diff] [blame] | 214 | /** |
| 215 | * bdi_sync_writeback - start and wait for writeback |
| 216 | * @bdi: the backing device to write from |
| 217 | * @sb: write inodes from this super_block |
| 218 | * |
| 219 | * Description: |
| 220 | * This does WB_SYNC_ALL data integrity writeback and waits for the |
| 221 | * IO to complete. Callers must hold the sb s_umount semaphore for |
| 222 | * reading, to avoid having the super disappear before we are done. |
| 223 | */ |
| 224 | static void bdi_sync_writeback(struct backing_dev_info *bdi, |
| 225 | struct super_block *sb) |
Jens Axboe | 03ba378 | 2009-09-09 09:08:54 +0200 | [diff] [blame] | 226 | { |
Jens Axboe | b6e5131 | 2009-09-16 15:13:54 +0200 | [diff] [blame] | 227 | struct wb_writeback_args args = { |
| 228 | .sb = sb, |
| 229 | .sync_mode = WB_SYNC_ALL, |
| 230 | .nr_pages = LONG_MAX, |
| 231 | .range_cyclic = 0, |
| 232 | }; |
| 233 | struct bdi_work work; |
Christoph Hellwig | f0fad8a | 2009-09-11 09:47:56 +0200 | [diff] [blame] | 234 | |
Jens Axboe | b6e5131 | 2009-09-16 15:13:54 +0200 | [diff] [blame] | 235 | bdi_work_init(&work, &args); |
| 236 | work.state |= WS_ONSTACK; |
Christoph Hellwig | f0fad8a | 2009-09-11 09:47:56 +0200 | [diff] [blame] | 237 | |
Jens Axboe | b6e5131 | 2009-09-16 15:13:54 +0200 | [diff] [blame] | 238 | bdi_queue_work(bdi, &work); |
| 239 | bdi_wait_on_work_clear(&work); |
| 240 | } |
| 241 | |
| 242 | /** |
| 243 | * bdi_start_writeback - start writeback |
| 244 | * @bdi: the backing device to write from |
Jaswinder Singh Rajput | 4b6764f | 2010-01-01 20:35:23 -0800 | [diff] [blame] | 245 | * @sb: write inodes from this super_block |
Jens Axboe | b6e5131 | 2009-09-16 15:13:54 +0200 | [diff] [blame] | 246 | * @nr_pages: the number of pages to write |
| 247 | * |
| 248 | * Description: |
| 249 | * This does WB_SYNC_NONE opportunistic writeback. The IO is only |
| 250 | * started when this function returns, we make no guarentees on |
| 251 | * completion. Caller need not hold sb s_umount semaphore. |
| 252 | * |
| 253 | */ |
Jens Axboe | a72bfd4 | 2009-09-26 00:07:46 +0200 | [diff] [blame] | 254 | void bdi_start_writeback(struct backing_dev_info *bdi, struct super_block *sb, |
| 255 | long nr_pages) |
Jens Axboe | b6e5131 | 2009-09-16 15:13:54 +0200 | [diff] [blame] | 256 | { |
| 257 | struct wb_writeback_args args = { |
Jens Axboe | a72bfd4 | 2009-09-26 00:07:46 +0200 | [diff] [blame] | 258 | .sb = sb, |
Jens Axboe | b6e5131 | 2009-09-16 15:13:54 +0200 | [diff] [blame] | 259 | .sync_mode = WB_SYNC_NONE, |
| 260 | .nr_pages = nr_pages, |
| 261 | .range_cyclic = 1, |
| 262 | }; |
| 263 | |
Wu Fengguang | d3ddec7 | 2009-09-23 20:33:40 +0800 | [diff] [blame] | 264 | /* |
| 265 | * We treat @nr_pages=0 as the special case to do background writeback, |
| 266 | * ie. to sync pages until the background dirty threshold is reached. |
| 267 | */ |
| 268 | if (!nr_pages) { |
| 269 | args.nr_pages = LONG_MAX; |
| 270 | args.for_background = 1; |
| 271 | } |
| 272 | |
Jens Axboe | b6e5131 | 2009-09-16 15:13:54 +0200 | [diff] [blame] | 273 | bdi_alloc_queue_work(bdi, &args); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 274 | } |
| 275 | |
| 276 | /* |
Andrew Morton | 6610a0b | 2007-10-16 23:30:32 -0700 | [diff] [blame] | 277 | * Redirty an inode: set its when-it-was dirtied timestamp and move it to the |
| 278 | * furthest end of its superblock's dirty-inode list. |
| 279 | * |
| 280 | * Before stamping the inode's ->dirtied_when, we check to see whether it is |
Jens Axboe | 66f3b8e | 2009-09-02 09:19:46 +0200 | [diff] [blame] | 281 | * already the most-recently-dirtied inode on the b_dirty list. If that is |
Andrew Morton | 6610a0b | 2007-10-16 23:30:32 -0700 | [diff] [blame] | 282 | * the case then the inode must have been redirtied while it was being written |
| 283 | * out and we don't reset its dirtied_when. |
| 284 | */ |
| 285 | static void redirty_tail(struct inode *inode) |
| 286 | { |
Jens Axboe | 03ba378 | 2009-09-09 09:08:54 +0200 | [diff] [blame] | 287 | struct bdi_writeback *wb = &inode_to_bdi(inode)->wb; |
Andrew Morton | 6610a0b | 2007-10-16 23:30:32 -0700 | [diff] [blame] | 288 | |
Jens Axboe | 03ba378 | 2009-09-09 09:08:54 +0200 | [diff] [blame] | 289 | if (!list_empty(&wb->b_dirty)) { |
Jens Axboe | 66f3b8e | 2009-09-02 09:19:46 +0200 | [diff] [blame] | 290 | struct inode *tail; |
Andrew Morton | 6610a0b | 2007-10-16 23:30:32 -0700 | [diff] [blame] | 291 | |
Jens Axboe | 03ba378 | 2009-09-09 09:08:54 +0200 | [diff] [blame] | 292 | tail = list_entry(wb->b_dirty.next, struct inode, i_list); |
Jens Axboe | 66f3b8e | 2009-09-02 09:19:46 +0200 | [diff] [blame] | 293 | if (time_before(inode->dirtied_when, tail->dirtied_when)) |
Andrew Morton | 6610a0b | 2007-10-16 23:30:32 -0700 | [diff] [blame] | 294 | inode->dirtied_when = jiffies; |
| 295 | } |
Jens Axboe | 03ba378 | 2009-09-09 09:08:54 +0200 | [diff] [blame] | 296 | list_move(&inode->i_list, &wb->b_dirty); |
Andrew Morton | 6610a0b | 2007-10-16 23:30:32 -0700 | [diff] [blame] | 297 | } |
| 298 | |
| 299 | /* |
Jens Axboe | 66f3b8e | 2009-09-02 09:19:46 +0200 | [diff] [blame] | 300 | * requeue inode for re-scanning after bdi->b_io list is exhausted. |
Andrew Morton | c986d1e | 2007-10-16 23:30:34 -0700 | [diff] [blame] | 301 | */ |
Ken Chen | 0e0f4fc | 2007-10-16 23:30:38 -0700 | [diff] [blame] | 302 | static void requeue_io(struct inode *inode) |
Andrew Morton | c986d1e | 2007-10-16 23:30:34 -0700 | [diff] [blame] | 303 | { |
Jens Axboe | 03ba378 | 2009-09-09 09:08:54 +0200 | [diff] [blame] | 304 | struct bdi_writeback *wb = &inode_to_bdi(inode)->wb; |
| 305 | |
| 306 | list_move(&inode->i_list, &wb->b_more_io); |
Andrew Morton | c986d1e | 2007-10-16 23:30:34 -0700 | [diff] [blame] | 307 | } |
| 308 | |
Joern Engel | 1c0eeaf | 2007-10-16 23:30:44 -0700 | [diff] [blame] | 309 | static void inode_sync_complete(struct inode *inode) |
| 310 | { |
| 311 | /* |
| 312 | * Prevent speculative execution through spin_unlock(&inode_lock); |
| 313 | */ |
| 314 | smp_mb(); |
| 315 | wake_up_bit(&inode->i_state, __I_SYNC); |
| 316 | } |
| 317 | |
Jeff Layton | d2caa3c5 | 2009-04-02 16:56:37 -0700 | [diff] [blame] | 318 | static bool inode_dirtied_after(struct inode *inode, unsigned long t) |
| 319 | { |
| 320 | bool ret = time_after(inode->dirtied_when, t); |
| 321 | #ifndef CONFIG_64BIT |
| 322 | /* |
| 323 | * For inodes being constantly redirtied, dirtied_when can get stuck. |
| 324 | * It _appears_ to be in the future, but is actually in distant past. |
| 325 | * This test is necessary to prevent such wrapped-around relative times |
Jens Axboe | 5b0830c | 2009-09-23 19:37:09 +0200 | [diff] [blame] | 326 | * from permanently stopping the whole bdi writeback. |
Jeff Layton | d2caa3c5 | 2009-04-02 16:56:37 -0700 | [diff] [blame] | 327 | */ |
| 328 | ret = ret && time_before_eq(inode->dirtied_when, jiffies); |
| 329 | #endif |
| 330 | return ret; |
| 331 | } |
| 332 | |
Andrew Morton | c986d1e | 2007-10-16 23:30:34 -0700 | [diff] [blame] | 333 | /* |
Fengguang Wu | 2c13657 | 2007-10-16 23:30:39 -0700 | [diff] [blame] | 334 | * Move expired dirty inodes from @delaying_queue to @dispatch_queue. |
| 335 | */ |
| 336 | static void move_expired_inodes(struct list_head *delaying_queue, |
| 337 | struct list_head *dispatch_queue, |
| 338 | unsigned long *older_than_this) |
| 339 | { |
Shaohua Li | 5c03449 | 2009-09-24 14:42:33 +0200 | [diff] [blame] | 340 | LIST_HEAD(tmp); |
| 341 | struct list_head *pos, *node; |
Jens Axboe | cf13730 | 2009-09-24 15:12:57 +0200 | [diff] [blame] | 342 | struct super_block *sb = NULL; |
Shaohua Li | 5c03449 | 2009-09-24 14:42:33 +0200 | [diff] [blame] | 343 | struct inode *inode; |
Jens Axboe | cf13730 | 2009-09-24 15:12:57 +0200 | [diff] [blame] | 344 | int do_sb_sort = 0; |
Shaohua Li | 5c03449 | 2009-09-24 14:42:33 +0200 | [diff] [blame] | 345 | |
Fengguang Wu | 2c13657 | 2007-10-16 23:30:39 -0700 | [diff] [blame] | 346 | while (!list_empty(delaying_queue)) { |
Shaohua Li | 5c03449 | 2009-09-24 14:42:33 +0200 | [diff] [blame] | 347 | inode = list_entry(delaying_queue->prev, struct inode, i_list); |
Fengguang Wu | 2c13657 | 2007-10-16 23:30:39 -0700 | [diff] [blame] | 348 | if (older_than_this && |
Jeff Layton | d2caa3c5 | 2009-04-02 16:56:37 -0700 | [diff] [blame] | 349 | inode_dirtied_after(inode, *older_than_this)) |
Fengguang Wu | 2c13657 | 2007-10-16 23:30:39 -0700 | [diff] [blame] | 350 | break; |
Jens Axboe | cf13730 | 2009-09-24 15:12:57 +0200 | [diff] [blame] | 351 | if (sb && sb != inode->i_sb) |
| 352 | do_sb_sort = 1; |
| 353 | sb = inode->i_sb; |
Shaohua Li | 5c03449 | 2009-09-24 14:42:33 +0200 | [diff] [blame] | 354 | list_move(&inode->i_list, &tmp); |
| 355 | } |
| 356 | |
Jens Axboe | cf13730 | 2009-09-24 15:12:57 +0200 | [diff] [blame] | 357 | /* just one sb in list, splice to dispatch_queue and we're done */ |
| 358 | if (!do_sb_sort) { |
| 359 | list_splice(&tmp, dispatch_queue); |
| 360 | return; |
| 361 | } |
| 362 | |
Shaohua Li | 5c03449 | 2009-09-24 14:42:33 +0200 | [diff] [blame] | 363 | /* Move inodes from one superblock together */ |
| 364 | while (!list_empty(&tmp)) { |
| 365 | inode = list_entry(tmp.prev, struct inode, i_list); |
| 366 | sb = inode->i_sb; |
| 367 | list_for_each_prev_safe(pos, node, &tmp) { |
| 368 | inode = list_entry(pos, struct inode, i_list); |
| 369 | if (inode->i_sb == sb) |
| 370 | list_move(&inode->i_list, dispatch_queue); |
| 371 | } |
Fengguang Wu | 2c13657 | 2007-10-16 23:30:39 -0700 | [diff] [blame] | 372 | } |
| 373 | } |
| 374 | |
| 375 | /* |
| 376 | * Queue all expired dirty inodes for io, eldest first. |
| 377 | */ |
Jens Axboe | 03ba378 | 2009-09-09 09:08:54 +0200 | [diff] [blame] | 378 | static void queue_io(struct bdi_writeback *wb, unsigned long *older_than_this) |
Fengguang Wu | 2c13657 | 2007-10-16 23:30:39 -0700 | [diff] [blame] | 379 | { |
Jens Axboe | 03ba378 | 2009-09-09 09:08:54 +0200 | [diff] [blame] | 380 | list_splice_init(&wb->b_more_io, wb->b_io.prev); |
| 381 | move_expired_inodes(&wb->b_dirty, &wb->b_io, older_than_this); |
Jens Axboe | 66f3b8e | 2009-09-02 09:19:46 +0200 | [diff] [blame] | 382 | } |
| 383 | |
Christoph Hellwig | a9185b4 | 2010-03-05 09:21:37 +0100 | [diff] [blame^] | 384 | static int write_inode(struct inode *inode, struct writeback_control *wbc) |
Jens Axboe | 66f3b8e | 2009-09-02 09:19:46 +0200 | [diff] [blame] | 385 | { |
Jens Axboe | 03ba378 | 2009-09-09 09:08:54 +0200 | [diff] [blame] | 386 | if (inode->i_sb->s_op->write_inode && !is_bad_inode(inode)) |
Christoph Hellwig | a9185b4 | 2010-03-05 09:21:37 +0100 | [diff] [blame^] | 387 | return inode->i_sb->s_op->write_inode(inode, wbc); |
Jens Axboe | 03ba378 | 2009-09-09 09:08:54 +0200 | [diff] [blame] | 388 | return 0; |
Fengguang Wu | 2c13657 | 2007-10-16 23:30:39 -0700 | [diff] [blame] | 389 | } |
| 390 | |
| 391 | /* |
Christoph Hellwig | 01c0319 | 2009-06-08 13:35:40 +0200 | [diff] [blame] | 392 | * Wait for writeback on an inode to complete. |
| 393 | */ |
| 394 | static void inode_wait_for_writeback(struct inode *inode) |
| 395 | { |
| 396 | DEFINE_WAIT_BIT(wq, &inode->i_state, __I_SYNC); |
| 397 | wait_queue_head_t *wqh; |
| 398 | |
| 399 | wqh = bit_waitqueue(&inode->i_state, __I_SYNC); |
| 400 | do { |
| 401 | spin_unlock(&inode_lock); |
| 402 | __wait_on_bit(wqh, &wq, inode_wait, TASK_UNINTERRUPTIBLE); |
| 403 | spin_lock(&inode_lock); |
| 404 | } while (inode->i_state & I_SYNC); |
| 405 | } |
| 406 | |
| 407 | /* |
| 408 | * Write out an inode's dirty pages. Called under inode_lock. Either the |
| 409 | * caller has ref on the inode (either via __iget or via syscall against an fd) |
| 410 | * or the inode has I_WILL_FREE set (via generic_forget_inode) |
| 411 | * |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 412 | * If `wait' is set, wait on the writeout. |
| 413 | * |
| 414 | * The whole writeout design is quite complex and fragile. We want to avoid |
| 415 | * starvation of particular inodes when others are being redirtied, prevent |
| 416 | * livelocks, etc. |
| 417 | * |
| 418 | * Called under inode_lock. |
| 419 | */ |
| 420 | static int |
Christoph Hellwig | 01c0319 | 2009-06-08 13:35:40 +0200 | [diff] [blame] | 421 | writeback_single_inode(struct inode *inode, struct writeback_control *wbc) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 422 | { |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 423 | struct address_space *mapping = inode->i_mapping; |
Christoph Hellwig | 01c0319 | 2009-06-08 13:35:40 +0200 | [diff] [blame] | 424 | unsigned dirty; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 425 | int ret; |
| 426 | |
Christoph Hellwig | 01c0319 | 2009-06-08 13:35:40 +0200 | [diff] [blame] | 427 | if (!atomic_read(&inode->i_count)) |
| 428 | WARN_ON(!(inode->i_state & (I_WILL_FREE|I_FREEING))); |
| 429 | else |
| 430 | WARN_ON(inode->i_state & I_WILL_FREE); |
| 431 | |
| 432 | if (inode->i_state & I_SYNC) { |
| 433 | /* |
| 434 | * If this inode is locked for writeback and we are not doing |
Jens Axboe | 66f3b8e | 2009-09-02 09:19:46 +0200 | [diff] [blame] | 435 | * writeback-for-data-integrity, move it to b_more_io so that |
Christoph Hellwig | 01c0319 | 2009-06-08 13:35:40 +0200 | [diff] [blame] | 436 | * writeback can proceed with the other inodes on s_io. |
| 437 | * |
| 438 | * We'll have another go at writing back this inode when we |
Jens Axboe | 66f3b8e | 2009-09-02 09:19:46 +0200 | [diff] [blame] | 439 | * completed a full scan of b_io. |
Christoph Hellwig | 01c0319 | 2009-06-08 13:35:40 +0200 | [diff] [blame] | 440 | */ |
Christoph Hellwig | a9185b4 | 2010-03-05 09:21:37 +0100 | [diff] [blame^] | 441 | if (wbc->sync_mode != WB_SYNC_ALL) { |
Christoph Hellwig | 01c0319 | 2009-06-08 13:35:40 +0200 | [diff] [blame] | 442 | requeue_io(inode); |
| 443 | return 0; |
| 444 | } |
| 445 | |
| 446 | /* |
| 447 | * It's a data-integrity sync. We must wait. |
| 448 | */ |
| 449 | inode_wait_for_writeback(inode); |
| 450 | } |
| 451 | |
Joern Engel | 1c0eeaf | 2007-10-16 23:30:44 -0700 | [diff] [blame] | 452 | BUG_ON(inode->i_state & I_SYNC); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 453 | |
Joern Engel | 1c0eeaf | 2007-10-16 23:30:44 -0700 | [diff] [blame] | 454 | /* Set I_SYNC, reset I_DIRTY */ |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 455 | dirty = inode->i_state & I_DIRTY; |
Joern Engel | 1c0eeaf | 2007-10-16 23:30:44 -0700 | [diff] [blame] | 456 | inode->i_state |= I_SYNC; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 457 | inode->i_state &= ~I_DIRTY; |
| 458 | |
| 459 | spin_unlock(&inode_lock); |
| 460 | |
| 461 | ret = do_writepages(mapping, wbc); |
| 462 | |
Christoph Hellwig | 26821ed | 2010-03-05 09:21:21 +0100 | [diff] [blame] | 463 | /* |
| 464 | * Make sure to wait on the data before writing out the metadata. |
| 465 | * This is important for filesystems that modify metadata on data |
| 466 | * I/O completion. |
| 467 | */ |
Christoph Hellwig | a9185b4 | 2010-03-05 09:21:37 +0100 | [diff] [blame^] | 468 | if (wbc->sync_mode == WB_SYNC_ALL) { |
Christoph Hellwig | 26821ed | 2010-03-05 09:21:21 +0100 | [diff] [blame] | 469 | int err = filemap_fdatawait(mapping); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 470 | if (ret == 0) |
| 471 | ret = err; |
| 472 | } |
| 473 | |
Christoph Hellwig | 26821ed | 2010-03-05 09:21:21 +0100 | [diff] [blame] | 474 | /* Don't write the inode if only I_DIRTY_PAGES was set */ |
| 475 | if (dirty & (I_DIRTY_SYNC | I_DIRTY_DATASYNC)) { |
Christoph Hellwig | a9185b4 | 2010-03-05 09:21:37 +0100 | [diff] [blame^] | 476 | int err = write_inode(inode, wbc); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 477 | if (ret == 0) |
| 478 | ret = err; |
| 479 | } |
| 480 | |
| 481 | spin_lock(&inode_lock); |
Joern Engel | 1c0eeaf | 2007-10-16 23:30:44 -0700 | [diff] [blame] | 482 | inode->i_state &= ~I_SYNC; |
Wu Fengguang | 84a8924 | 2009-06-16 15:33:17 -0700 | [diff] [blame] | 483 | if (!(inode->i_state & (I_FREEING | I_CLEAR))) { |
Wu Fengguang | b3af946 | 2009-09-25 06:04:10 +0200 | [diff] [blame] | 484 | if ((inode->i_state & I_DIRTY_PAGES) && wbc->for_kupdate) { |
Wu Fengguang | ae1b7f7 | 2009-09-23 20:33:42 +0800 | [diff] [blame] | 485 | /* |
Wu Fengguang | b3af946 | 2009-09-25 06:04:10 +0200 | [diff] [blame] | 486 | * More pages get dirtied by a fast dirtier. |
| 487 | */ |
| 488 | goto select_queue; |
| 489 | } else if (inode->i_state & I_DIRTY) { |
| 490 | /* |
| 491 | * At least XFS will redirty the inode during the |
| 492 | * writeback (delalloc) and on io completion (isize). |
Wu Fengguang | ae1b7f7 | 2009-09-23 20:33:42 +0800 | [diff] [blame] | 493 | */ |
| 494 | redirty_tail(inode); |
| 495 | } else if (mapping_tagged(mapping, PAGECACHE_TAG_DIRTY)) { |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 496 | /* |
| 497 | * We didn't write back all the pages. nfs_writepages() |
| 498 | * sometimes bales out without doing anything. Redirty |
Jens Axboe | 66f3b8e | 2009-09-02 09:19:46 +0200 | [diff] [blame] | 499 | * the inode; Move it from b_io onto b_more_io/b_dirty. |
Andrew Morton | 1b43ef9 | 2007-10-16 23:30:35 -0700 | [diff] [blame] | 500 | */ |
| 501 | /* |
| 502 | * akpm: if the caller was the kupdate function we put |
Jens Axboe | 66f3b8e | 2009-09-02 09:19:46 +0200 | [diff] [blame] | 503 | * this inode at the head of b_dirty so it gets first |
Andrew Morton | 1b43ef9 | 2007-10-16 23:30:35 -0700 | [diff] [blame] | 504 | * consideration. Otherwise, move it to the tail, for |
| 505 | * the reasons described there. I'm not really sure |
| 506 | * how much sense this makes. Presumably I had a good |
| 507 | * reasons for doing it this way, and I'd rather not |
| 508 | * muck with it at present. |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 509 | */ |
| 510 | if (wbc->for_kupdate) { |
| 511 | /* |
Fengguang Wu | 2c13657 | 2007-10-16 23:30:39 -0700 | [diff] [blame] | 512 | * For the kupdate function we move the inode |
Jens Axboe | 66f3b8e | 2009-09-02 09:19:46 +0200 | [diff] [blame] | 513 | * to b_more_io so it will get more writeout as |
Fengguang Wu | 2c13657 | 2007-10-16 23:30:39 -0700 | [diff] [blame] | 514 | * soon as the queue becomes uncongested. |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 515 | */ |
| 516 | inode->i_state |= I_DIRTY_PAGES; |
Wu Fengguang | b3af946 | 2009-09-25 06:04:10 +0200 | [diff] [blame] | 517 | select_queue: |
Fengguang Wu | 8bc3be2 | 2008-02-04 22:29:36 -0800 | [diff] [blame] | 518 | if (wbc->nr_to_write <= 0) { |
| 519 | /* |
| 520 | * slice used up: queue for next turn |
| 521 | */ |
| 522 | requeue_io(inode); |
| 523 | } else { |
| 524 | /* |
| 525 | * somehow blocked: retry later |
| 526 | */ |
| 527 | redirty_tail(inode); |
| 528 | } |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 529 | } else { |
| 530 | /* |
| 531 | * Otherwise fully redirty the inode so that |
| 532 | * other inodes on this superblock will get some |
| 533 | * writeout. Otherwise heavy writing to one |
| 534 | * file would indefinitely suspend writeout of |
| 535 | * all the other files. |
| 536 | */ |
| 537 | inode->i_state |= I_DIRTY_PAGES; |
Andrew Morton | 1b43ef9 | 2007-10-16 23:30:35 -0700 | [diff] [blame] | 538 | redirty_tail(inode); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 539 | } |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 540 | } else if (atomic_read(&inode->i_count)) { |
| 541 | /* |
| 542 | * The inode is clean, inuse |
| 543 | */ |
| 544 | list_move(&inode->i_list, &inode_in_use); |
| 545 | } else { |
| 546 | /* |
| 547 | * The inode is clean, unused |
| 548 | */ |
| 549 | list_move(&inode->i_list, &inode_unused); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 550 | } |
| 551 | } |
Joern Engel | 1c0eeaf | 2007-10-16 23:30:44 -0700 | [diff] [blame] | 552 | inode_sync_complete(inode); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 553 | return ret; |
| 554 | } |
| 555 | |
Jens Axboe | 9ecc273 | 2009-09-24 15:25:11 +0200 | [diff] [blame] | 556 | static void unpin_sb_for_writeback(struct super_block **psb) |
| 557 | { |
| 558 | struct super_block *sb = *psb; |
| 559 | |
| 560 | if (sb) { |
| 561 | up_read(&sb->s_umount); |
| 562 | put_super(sb); |
| 563 | *psb = NULL; |
| 564 | } |
| 565 | } |
| 566 | |
Jens Axboe | 03ba378 | 2009-09-09 09:08:54 +0200 | [diff] [blame] | 567 | /* |
| 568 | * For WB_SYNC_NONE writeback, the caller does not have the sb pinned |
| 569 | * before calling writeback. So make sure that we do pin it, so it doesn't |
| 570 | * go away while we are writing inodes from it. |
| 571 | * |
| 572 | * Returns 0 if the super was successfully pinned (or pinning wasn't needed), |
| 573 | * 1 if we failed. |
| 574 | */ |
| 575 | static int pin_sb_for_writeback(struct writeback_control *wbc, |
Jens Axboe | 9ecc273 | 2009-09-24 15:25:11 +0200 | [diff] [blame] | 576 | struct inode *inode, struct super_block **psb) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 577 | { |
Jens Axboe | 03ba378 | 2009-09-09 09:08:54 +0200 | [diff] [blame] | 578 | struct super_block *sb = inode->i_sb; |
| 579 | |
| 580 | /* |
Jens Axboe | 9ecc273 | 2009-09-24 15:25:11 +0200 | [diff] [blame] | 581 | * If this sb is already pinned, nothing more to do. If not and |
| 582 | * *psb is non-NULL, unpin the old one first |
| 583 | */ |
| 584 | if (sb == *psb) |
| 585 | return 0; |
| 586 | else if (*psb) |
| 587 | unpin_sb_for_writeback(psb); |
| 588 | |
| 589 | /* |
Jens Axboe | 03ba378 | 2009-09-09 09:08:54 +0200 | [diff] [blame] | 590 | * Caller must already hold the ref for this |
| 591 | */ |
| 592 | if (wbc->sync_mode == WB_SYNC_ALL) { |
| 593 | WARN_ON(!rwsem_is_locked(&sb->s_umount)); |
| 594 | return 0; |
| 595 | } |
| 596 | |
| 597 | spin_lock(&sb_lock); |
| 598 | sb->s_count++; |
| 599 | if (down_read_trylock(&sb->s_umount)) { |
| 600 | if (sb->s_root) { |
| 601 | spin_unlock(&sb_lock); |
Jens Axboe | 9ecc273 | 2009-09-24 15:25:11 +0200 | [diff] [blame] | 602 | goto pinned; |
Jens Axboe | 03ba378 | 2009-09-09 09:08:54 +0200 | [diff] [blame] | 603 | } |
| 604 | /* |
| 605 | * umounted, drop rwsem again and fall through to failure |
| 606 | */ |
| 607 | up_read(&sb->s_umount); |
| 608 | } |
| 609 | |
| 610 | sb->s_count--; |
| 611 | spin_unlock(&sb_lock); |
| 612 | return 1; |
Jens Axboe | 9ecc273 | 2009-09-24 15:25:11 +0200 | [diff] [blame] | 613 | pinned: |
| 614 | *psb = sb; |
| 615 | return 0; |
Jens Axboe | 03ba378 | 2009-09-09 09:08:54 +0200 | [diff] [blame] | 616 | } |
| 617 | |
| 618 | static void writeback_inodes_wb(struct bdi_writeback *wb, |
| 619 | struct writeback_control *wbc) |
| 620 | { |
Jens Axboe | 9ecc273 | 2009-09-24 15:25:11 +0200 | [diff] [blame] | 621 | struct super_block *sb = wbc->sb, *pin_sb = NULL; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 622 | const unsigned long start = jiffies; /* livelock avoidance */ |
| 623 | |
Hans Reiser | ae8547b | 2008-05-07 15:48:57 +0300 | [diff] [blame] | 624 | spin_lock(&inode_lock); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 625 | |
Jens Axboe | 03ba378 | 2009-09-09 09:08:54 +0200 | [diff] [blame] | 626 | if (!wbc->for_kupdate || list_empty(&wb->b_io)) |
| 627 | queue_io(wb, wbc->older_than_this); |
Jens Axboe | 66f3b8e | 2009-09-02 09:19:46 +0200 | [diff] [blame] | 628 | |
Jens Axboe | 03ba378 | 2009-09-09 09:08:54 +0200 | [diff] [blame] | 629 | while (!list_empty(&wb->b_io)) { |
| 630 | struct inode *inode = list_entry(wb->b_io.prev, |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 631 | struct inode, i_list); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 632 | long pages_skipped; |
| 633 | |
Jens Axboe | 66f3b8e | 2009-09-02 09:19:46 +0200 | [diff] [blame] | 634 | /* |
| 635 | * super block given and doesn't match, skip this inode |
| 636 | */ |
| 637 | if (sb && sb != inode->i_sb) { |
| 638 | redirty_tail(inode); |
| 639 | continue; |
| 640 | } |
| 641 | |
Wu Fengguang | 84a8924 | 2009-06-16 15:33:17 -0700 | [diff] [blame] | 642 | if (inode->i_state & (I_NEW | I_WILL_FREE)) { |
Nick Piggin | 7ef0d73 | 2009-03-12 14:31:38 -0700 | [diff] [blame] | 643 | requeue_io(inode); |
| 644 | continue; |
| 645 | } |
| 646 | |
Jeff Layton | d2caa3c5 | 2009-04-02 16:56:37 -0700 | [diff] [blame] | 647 | /* |
| 648 | * Was this inode dirtied after sync_sb_inodes was called? |
| 649 | * This keeps sync from extra jobs and livelock. |
| 650 | */ |
| 651 | if (inode_dirtied_after(inode, start)) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 652 | break; |
| 653 | |
Jens Axboe | 9ecc273 | 2009-09-24 15:25:11 +0200 | [diff] [blame] | 654 | if (pin_sb_for_writeback(wbc, inode, &pin_sb)) { |
Jens Axboe | 03ba378 | 2009-09-09 09:08:54 +0200 | [diff] [blame] | 655 | requeue_io(inode); |
| 656 | continue; |
| 657 | } |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 658 | |
Wu Fengguang | 84a8924 | 2009-06-16 15:33:17 -0700 | [diff] [blame] | 659 | BUG_ON(inode->i_state & (I_FREEING | I_CLEAR)); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 660 | __iget(inode); |
| 661 | pages_skipped = wbc->pages_skipped; |
Christoph Hellwig | 01c0319 | 2009-06-08 13:35:40 +0200 | [diff] [blame] | 662 | writeback_single_inode(inode, wbc); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 663 | if (wbc->pages_skipped != pages_skipped) { |
| 664 | /* |
| 665 | * writeback is not making progress due to locked |
| 666 | * buffers. Skip this inode for now. |
| 667 | */ |
Andrew Morton | f57b9b7 | 2007-10-16 23:30:34 -0700 | [diff] [blame] | 668 | redirty_tail(inode); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 669 | } |
| 670 | spin_unlock(&inode_lock); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 671 | iput(inode); |
OGAWA Hirofumi | 4ffc844 | 2006-03-25 03:07:44 -0800 | [diff] [blame] | 672 | cond_resched(); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 673 | spin_lock(&inode_lock); |
Fengguang Wu | 8bc3be2 | 2008-02-04 22:29:36 -0800 | [diff] [blame] | 674 | if (wbc->nr_to_write <= 0) { |
| 675 | wbc->more_io = 1; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 676 | break; |
Fengguang Wu | 8bc3be2 | 2008-02-04 22:29:36 -0800 | [diff] [blame] | 677 | } |
Jens Axboe | 03ba378 | 2009-09-09 09:08:54 +0200 | [diff] [blame] | 678 | if (!list_empty(&wb->b_more_io)) |
Fengguang Wu | 8bc3be2 | 2008-02-04 22:29:36 -0800 | [diff] [blame] | 679 | wbc->more_io = 1; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 680 | } |
Nick Piggin | 38f2197 | 2009-01-06 14:40:25 -0800 | [diff] [blame] | 681 | |
Jens Axboe | 9ecc273 | 2009-09-24 15:25:11 +0200 | [diff] [blame] | 682 | unpin_sb_for_writeback(&pin_sb); |
| 683 | |
Jens Axboe | 66f3b8e | 2009-09-02 09:19:46 +0200 | [diff] [blame] | 684 | spin_unlock(&inode_lock); |
| 685 | /* Leave any unwritten inodes on b_io */ |
| 686 | } |
| 687 | |
Jens Axboe | 03ba378 | 2009-09-09 09:08:54 +0200 | [diff] [blame] | 688 | void writeback_inodes_wbc(struct writeback_control *wbc) |
| 689 | { |
| 690 | struct backing_dev_info *bdi = wbc->bdi; |
| 691 | |
| 692 | writeback_inodes_wb(&bdi->wb, wbc); |
| 693 | } |
| 694 | |
| 695 | /* |
| 696 | * The maximum number of pages to writeout in a single bdi flush/kupdate |
| 697 | * operation. We do this so we don't hold I_SYNC against an inode for |
| 698 | * enormous amounts of time, which would block a userspace task which has |
| 699 | * been forced to throttle against that inode. Also, the code reevaluates |
| 700 | * the dirty each time it has written this many pages. |
| 701 | */ |
| 702 | #define MAX_WRITEBACK_PAGES 1024 |
| 703 | |
| 704 | static inline bool over_bground_thresh(void) |
| 705 | { |
| 706 | unsigned long background_thresh, dirty_thresh; |
| 707 | |
| 708 | get_dirty_limits(&background_thresh, &dirty_thresh, NULL, NULL); |
| 709 | |
| 710 | return (global_page_state(NR_FILE_DIRTY) + |
| 711 | global_page_state(NR_UNSTABLE_NFS) >= background_thresh); |
| 712 | } |
| 713 | |
| 714 | /* |
| 715 | * Explicit flushing or periodic writeback of "old" data. |
| 716 | * |
| 717 | * Define "old": the first time one of an inode's pages is dirtied, we mark the |
| 718 | * dirtying-time in the inode's address_space. So this periodic writeback code |
| 719 | * just walks the superblock inode list, writing back any inodes which are |
| 720 | * older than a specific point in time. |
| 721 | * |
| 722 | * Try to run once per dirty_writeback_interval. But if a writeback event |
| 723 | * takes longer than a dirty_writeback_interval interval, then leave a |
| 724 | * one-second gap. |
| 725 | * |
| 726 | * older_than_this takes precedence over nr_to_write. So we'll only write back |
| 727 | * all dirty pages if they are all attached to "old" mappings. |
| 728 | */ |
Jens Axboe | c4a77a6 | 2009-09-16 15:18:25 +0200 | [diff] [blame] | 729 | static long wb_writeback(struct bdi_writeback *wb, |
| 730 | struct wb_writeback_args *args) |
Jens Axboe | 03ba378 | 2009-09-09 09:08:54 +0200 | [diff] [blame] | 731 | { |
| 732 | struct writeback_control wbc = { |
| 733 | .bdi = wb->bdi, |
Jens Axboe | c4a77a6 | 2009-09-16 15:18:25 +0200 | [diff] [blame] | 734 | .sb = args->sb, |
| 735 | .sync_mode = args->sync_mode, |
Jens Axboe | 03ba378 | 2009-09-09 09:08:54 +0200 | [diff] [blame] | 736 | .older_than_this = NULL, |
Jens Axboe | c4a77a6 | 2009-09-16 15:18:25 +0200 | [diff] [blame] | 737 | .for_kupdate = args->for_kupdate, |
Wu Fengguang | b17621f | 2009-12-03 13:54:25 +0100 | [diff] [blame] | 738 | .for_background = args->for_background, |
Jens Axboe | c4a77a6 | 2009-09-16 15:18:25 +0200 | [diff] [blame] | 739 | .range_cyclic = args->range_cyclic, |
Jens Axboe | 03ba378 | 2009-09-09 09:08:54 +0200 | [diff] [blame] | 740 | }; |
| 741 | unsigned long oldest_jif; |
| 742 | long wrote = 0; |
Jan Kara | a5989bd | 2009-09-16 19:22:48 +0200 | [diff] [blame] | 743 | struct inode *inode; |
Jens Axboe | 03ba378 | 2009-09-09 09:08:54 +0200 | [diff] [blame] | 744 | |
| 745 | if (wbc.for_kupdate) { |
| 746 | wbc.older_than_this = &oldest_jif; |
| 747 | oldest_jif = jiffies - |
| 748 | msecs_to_jiffies(dirty_expire_interval * 10); |
| 749 | } |
Jens Axboe | c4a77a6 | 2009-09-16 15:18:25 +0200 | [diff] [blame] | 750 | if (!wbc.range_cyclic) { |
| 751 | wbc.range_start = 0; |
| 752 | wbc.range_end = LLONG_MAX; |
| 753 | } |
Jens Axboe | 03ba378 | 2009-09-09 09:08:54 +0200 | [diff] [blame] | 754 | |
| 755 | for (;;) { |
| 756 | /* |
Wu Fengguang | d3ddec7 | 2009-09-23 20:33:40 +0800 | [diff] [blame] | 757 | * Stop writeback when nr_pages has been consumed |
Jens Axboe | 03ba378 | 2009-09-09 09:08:54 +0200 | [diff] [blame] | 758 | */ |
Wu Fengguang | d3ddec7 | 2009-09-23 20:33:40 +0800 | [diff] [blame] | 759 | if (args->nr_pages <= 0) |
Jens Axboe | 03ba378 | 2009-09-09 09:08:54 +0200 | [diff] [blame] | 760 | break; |
| 761 | |
| 762 | /* |
Wu Fengguang | d3ddec7 | 2009-09-23 20:33:40 +0800 | [diff] [blame] | 763 | * For background writeout, stop when we are below the |
| 764 | * background dirty threshold |
Jens Axboe | 03ba378 | 2009-09-09 09:08:54 +0200 | [diff] [blame] | 765 | */ |
Wu Fengguang | d3ddec7 | 2009-09-23 20:33:40 +0800 | [diff] [blame] | 766 | if (args->for_background && !over_bground_thresh()) |
Jens Axboe | 03ba378 | 2009-09-09 09:08:54 +0200 | [diff] [blame] | 767 | break; |
| 768 | |
| 769 | wbc.more_io = 0; |
Jens Axboe | 03ba378 | 2009-09-09 09:08:54 +0200 | [diff] [blame] | 770 | wbc.nr_to_write = MAX_WRITEBACK_PAGES; |
| 771 | wbc.pages_skipped = 0; |
| 772 | writeback_inodes_wb(wb, &wbc); |
Jens Axboe | c4a77a6 | 2009-09-16 15:18:25 +0200 | [diff] [blame] | 773 | args->nr_pages -= MAX_WRITEBACK_PAGES - wbc.nr_to_write; |
Jens Axboe | 03ba378 | 2009-09-09 09:08:54 +0200 | [diff] [blame] | 774 | wrote += MAX_WRITEBACK_PAGES - wbc.nr_to_write; |
| 775 | |
| 776 | /* |
Jens Axboe | 71fd05a | 2009-09-23 19:32:26 +0200 | [diff] [blame] | 777 | * If we consumed everything, see if we have more |
Jens Axboe | 03ba378 | 2009-09-09 09:08:54 +0200 | [diff] [blame] | 778 | */ |
Jens Axboe | 71fd05a | 2009-09-23 19:32:26 +0200 | [diff] [blame] | 779 | if (wbc.nr_to_write <= 0) |
| 780 | continue; |
| 781 | /* |
| 782 | * Didn't write everything and we don't have more IO, bail |
| 783 | */ |
| 784 | if (!wbc.more_io) |
Jens Axboe | 03ba378 | 2009-09-09 09:08:54 +0200 | [diff] [blame] | 785 | break; |
Jens Axboe | 71fd05a | 2009-09-23 19:32:26 +0200 | [diff] [blame] | 786 | /* |
| 787 | * Did we write something? Try for more |
| 788 | */ |
| 789 | if (wbc.nr_to_write < MAX_WRITEBACK_PAGES) |
| 790 | continue; |
| 791 | /* |
| 792 | * Nothing written. Wait for some inode to |
| 793 | * become available for writeback. Otherwise |
| 794 | * we'll just busyloop. |
| 795 | */ |
| 796 | spin_lock(&inode_lock); |
| 797 | if (!list_empty(&wb->b_more_io)) { |
| 798 | inode = list_entry(wb->b_more_io.prev, |
| 799 | struct inode, i_list); |
| 800 | inode_wait_for_writeback(inode); |
Jens Axboe | 03ba378 | 2009-09-09 09:08:54 +0200 | [diff] [blame] | 801 | } |
Jens Axboe | 71fd05a | 2009-09-23 19:32:26 +0200 | [diff] [blame] | 802 | spin_unlock(&inode_lock); |
Jens Axboe | 03ba378 | 2009-09-09 09:08:54 +0200 | [diff] [blame] | 803 | } |
| 804 | |
| 805 | return wrote; |
| 806 | } |
| 807 | |
| 808 | /* |
| 809 | * Return the next bdi_work struct that hasn't been processed by this |
Jens Axboe | 8010c3b | 2009-09-15 20:04:57 +0200 | [diff] [blame] | 810 | * wb thread yet. ->seen is initially set for each thread that exists |
| 811 | * for this device, when a thread first notices a piece of work it |
| 812 | * clears its bit. Depending on writeback type, the thread will notify |
| 813 | * completion on either receiving the work (WB_SYNC_NONE) or after |
| 814 | * it is done (WB_SYNC_ALL). |
Jens Axboe | 03ba378 | 2009-09-09 09:08:54 +0200 | [diff] [blame] | 815 | */ |
| 816 | static struct bdi_work *get_next_work_item(struct backing_dev_info *bdi, |
| 817 | struct bdi_writeback *wb) |
| 818 | { |
| 819 | struct bdi_work *work, *ret = NULL; |
| 820 | |
| 821 | rcu_read_lock(); |
| 822 | |
| 823 | list_for_each_entry_rcu(work, &bdi->work_list, list) { |
Nick Piggin | 77fad5e | 2009-09-15 21:34:12 +0200 | [diff] [blame] | 824 | if (!test_bit(wb->nr, &work->seen)) |
Jens Axboe | 03ba378 | 2009-09-09 09:08:54 +0200 | [diff] [blame] | 825 | continue; |
Nick Piggin | 77fad5e | 2009-09-15 21:34:12 +0200 | [diff] [blame] | 826 | clear_bit(wb->nr, &work->seen); |
Jens Axboe | 03ba378 | 2009-09-09 09:08:54 +0200 | [diff] [blame] | 827 | |
| 828 | ret = work; |
| 829 | break; |
| 830 | } |
| 831 | |
| 832 | rcu_read_unlock(); |
| 833 | return ret; |
| 834 | } |
| 835 | |
| 836 | static long wb_check_old_data_flush(struct bdi_writeback *wb) |
| 837 | { |
| 838 | unsigned long expired; |
| 839 | long nr_pages; |
| 840 | |
| 841 | expired = wb->last_old_flush + |
| 842 | msecs_to_jiffies(dirty_writeback_interval * 10); |
| 843 | if (time_before(jiffies, expired)) |
| 844 | return 0; |
| 845 | |
| 846 | wb->last_old_flush = jiffies; |
| 847 | nr_pages = global_page_state(NR_FILE_DIRTY) + |
| 848 | global_page_state(NR_UNSTABLE_NFS) + |
| 849 | (inodes_stat.nr_inodes - inodes_stat.nr_unused); |
| 850 | |
Jens Axboe | c4a77a6 | 2009-09-16 15:18:25 +0200 | [diff] [blame] | 851 | if (nr_pages) { |
| 852 | struct wb_writeback_args args = { |
| 853 | .nr_pages = nr_pages, |
| 854 | .sync_mode = WB_SYNC_NONE, |
| 855 | .for_kupdate = 1, |
| 856 | .range_cyclic = 1, |
| 857 | }; |
| 858 | |
| 859 | return wb_writeback(wb, &args); |
| 860 | } |
Jens Axboe | 03ba378 | 2009-09-09 09:08:54 +0200 | [diff] [blame] | 861 | |
| 862 | return 0; |
| 863 | } |
| 864 | |
| 865 | /* |
| 866 | * Retrieve work items and do the writeback they describe |
| 867 | */ |
| 868 | long wb_do_writeback(struct bdi_writeback *wb, int force_wait) |
| 869 | { |
| 870 | struct backing_dev_info *bdi = wb->bdi; |
| 871 | struct bdi_work *work; |
Jens Axboe | c4a77a6 | 2009-09-16 15:18:25 +0200 | [diff] [blame] | 872 | long wrote = 0; |
Jens Axboe | 03ba378 | 2009-09-09 09:08:54 +0200 | [diff] [blame] | 873 | |
| 874 | while ((work = get_next_work_item(bdi, wb)) != NULL) { |
Jens Axboe | c4a77a6 | 2009-09-16 15:18:25 +0200 | [diff] [blame] | 875 | struct wb_writeback_args args = work->args; |
Jens Axboe | 03ba378 | 2009-09-09 09:08:54 +0200 | [diff] [blame] | 876 | |
| 877 | /* |
| 878 | * Override sync mode, in case we must wait for completion |
| 879 | */ |
| 880 | if (force_wait) |
Jens Axboe | c4a77a6 | 2009-09-16 15:18:25 +0200 | [diff] [blame] | 881 | work->args.sync_mode = args.sync_mode = WB_SYNC_ALL; |
Jens Axboe | 03ba378 | 2009-09-09 09:08:54 +0200 | [diff] [blame] | 882 | |
| 883 | /* |
| 884 | * If this isn't a data integrity operation, just notify |
| 885 | * that we have seen this work and we are now starting it. |
| 886 | */ |
Jens Axboe | c4a77a6 | 2009-09-16 15:18:25 +0200 | [diff] [blame] | 887 | if (args.sync_mode == WB_SYNC_NONE) |
Jens Axboe | 03ba378 | 2009-09-09 09:08:54 +0200 | [diff] [blame] | 888 | wb_clear_pending(wb, work); |
| 889 | |
Jens Axboe | c4a77a6 | 2009-09-16 15:18:25 +0200 | [diff] [blame] | 890 | wrote += wb_writeback(wb, &args); |
Jens Axboe | 03ba378 | 2009-09-09 09:08:54 +0200 | [diff] [blame] | 891 | |
| 892 | /* |
| 893 | * This is a data integrity writeback, so only do the |
| 894 | * notification when we have completed the work. |
| 895 | */ |
Jens Axboe | c4a77a6 | 2009-09-16 15:18:25 +0200 | [diff] [blame] | 896 | if (args.sync_mode == WB_SYNC_ALL) |
Jens Axboe | 03ba378 | 2009-09-09 09:08:54 +0200 | [diff] [blame] | 897 | wb_clear_pending(wb, work); |
| 898 | } |
| 899 | |
| 900 | /* |
| 901 | * Check for periodic writeback, kupdated() style |
| 902 | */ |
| 903 | wrote += wb_check_old_data_flush(wb); |
| 904 | |
| 905 | return wrote; |
| 906 | } |
| 907 | |
| 908 | /* |
| 909 | * Handle writeback of dirty data for the device backed by this bdi. Also |
| 910 | * wakes up periodically and does kupdated style flushing. |
| 911 | */ |
| 912 | int bdi_writeback_task(struct bdi_writeback *wb) |
| 913 | { |
| 914 | unsigned long last_active = jiffies; |
| 915 | unsigned long wait_jiffies = -1UL; |
| 916 | long pages_written; |
| 917 | |
| 918 | while (!kthread_should_stop()) { |
| 919 | pages_written = wb_do_writeback(wb, 0); |
| 920 | |
| 921 | if (pages_written) |
| 922 | last_active = jiffies; |
| 923 | else if (wait_jiffies != -1UL) { |
| 924 | unsigned long max_idle; |
| 925 | |
| 926 | /* |
| 927 | * Longest period of inactivity that we tolerate. If we |
| 928 | * see dirty data again later, the task will get |
| 929 | * recreated automatically. |
| 930 | */ |
| 931 | max_idle = max(5UL * 60 * HZ, wait_jiffies); |
| 932 | if (time_after(jiffies, max_idle + last_active)) |
| 933 | break; |
| 934 | } |
| 935 | |
| 936 | wait_jiffies = msecs_to_jiffies(dirty_writeback_interval * 10); |
Jens Axboe | 49db041 | 2009-09-15 21:27:40 +0200 | [diff] [blame] | 937 | schedule_timeout_interruptible(wait_jiffies); |
Jens Axboe | 03ba378 | 2009-09-09 09:08:54 +0200 | [diff] [blame] | 938 | try_to_freeze(); |
| 939 | } |
| 940 | |
| 941 | return 0; |
| 942 | } |
| 943 | |
| 944 | /* |
Jens Axboe | b6e5131 | 2009-09-16 15:13:54 +0200 | [diff] [blame] | 945 | * Schedule writeback for all backing devices. This does WB_SYNC_NONE |
| 946 | * writeback, for integrity writeback see bdi_sync_writeback(). |
Jens Axboe | 03ba378 | 2009-09-09 09:08:54 +0200 | [diff] [blame] | 947 | */ |
Jens Axboe | b6e5131 | 2009-09-16 15:13:54 +0200 | [diff] [blame] | 948 | static void bdi_writeback_all(struct super_block *sb, long nr_pages) |
Jens Axboe | 03ba378 | 2009-09-09 09:08:54 +0200 | [diff] [blame] | 949 | { |
Jens Axboe | b6e5131 | 2009-09-16 15:13:54 +0200 | [diff] [blame] | 950 | struct wb_writeback_args args = { |
| 951 | .sb = sb, |
| 952 | .nr_pages = nr_pages, |
| 953 | .sync_mode = WB_SYNC_NONE, |
| 954 | }; |
Jens Axboe | 03ba378 | 2009-09-09 09:08:54 +0200 | [diff] [blame] | 955 | struct backing_dev_info *bdi; |
Jens Axboe | 03ba378 | 2009-09-09 09:08:54 +0200 | [diff] [blame] | 956 | |
Jens Axboe | cfc4ba5 | 2009-09-14 13:12:40 +0200 | [diff] [blame] | 957 | rcu_read_lock(); |
Jens Axboe | 03ba378 | 2009-09-09 09:08:54 +0200 | [diff] [blame] | 958 | |
Jens Axboe | cfc4ba5 | 2009-09-14 13:12:40 +0200 | [diff] [blame] | 959 | list_for_each_entry_rcu(bdi, &bdi_list, bdi_list) { |
Jens Axboe | 03ba378 | 2009-09-09 09:08:54 +0200 | [diff] [blame] | 960 | if (!bdi_has_dirty_io(bdi)) |
| 961 | continue; |
| 962 | |
Jens Axboe | b6e5131 | 2009-09-16 15:13:54 +0200 | [diff] [blame] | 963 | bdi_alloc_queue_work(bdi, &args); |
Jens Axboe | 03ba378 | 2009-09-09 09:08:54 +0200 | [diff] [blame] | 964 | } |
| 965 | |
Jens Axboe | cfc4ba5 | 2009-09-14 13:12:40 +0200 | [diff] [blame] | 966 | rcu_read_unlock(); |
Jens Axboe | 03ba378 | 2009-09-09 09:08:54 +0200 | [diff] [blame] | 967 | } |
| 968 | |
| 969 | /* |
| 970 | * Start writeback of `nr_pages' pages. If `nr_pages' is zero, write back |
| 971 | * the whole world. |
| 972 | */ |
| 973 | void wakeup_flusher_threads(long nr_pages) |
| 974 | { |
Jens Axboe | 03ba378 | 2009-09-09 09:08:54 +0200 | [diff] [blame] | 975 | if (nr_pages == 0) |
| 976 | nr_pages = global_page_state(NR_FILE_DIRTY) + |
| 977 | global_page_state(NR_UNSTABLE_NFS); |
Jens Axboe | b6e5131 | 2009-09-16 15:13:54 +0200 | [diff] [blame] | 978 | bdi_writeback_all(NULL, nr_pages); |
Jens Axboe | 03ba378 | 2009-09-09 09:08:54 +0200 | [diff] [blame] | 979 | } |
| 980 | |
| 981 | static noinline void block_dump___mark_inode_dirty(struct inode *inode) |
| 982 | { |
| 983 | if (inode->i_ino || strcmp(inode->i_sb->s_id, "bdev")) { |
| 984 | struct dentry *dentry; |
| 985 | const char *name = "?"; |
| 986 | |
| 987 | dentry = d_find_alias(inode); |
| 988 | if (dentry) { |
| 989 | spin_lock(&dentry->d_lock); |
| 990 | name = (const char *) dentry->d_name.name; |
| 991 | } |
| 992 | printk(KERN_DEBUG |
| 993 | "%s(%d): dirtied inode %lu (%s) on %s\n", |
| 994 | current->comm, task_pid_nr(current), inode->i_ino, |
| 995 | name, inode->i_sb->s_id); |
| 996 | if (dentry) { |
| 997 | spin_unlock(&dentry->d_lock); |
| 998 | dput(dentry); |
| 999 | } |
| 1000 | } |
| 1001 | } |
| 1002 | |
| 1003 | /** |
| 1004 | * __mark_inode_dirty - internal function |
| 1005 | * @inode: inode to mark |
| 1006 | * @flags: what kind of dirty (i.e. I_DIRTY_SYNC) |
| 1007 | * Mark an inode as dirty. Callers should use mark_inode_dirty or |
| 1008 | * mark_inode_dirty_sync. |
| 1009 | * |
| 1010 | * Put the inode on the super block's dirty list. |
| 1011 | * |
| 1012 | * CAREFUL! We mark it dirty unconditionally, but move it onto the |
| 1013 | * dirty list only if it is hashed or if it refers to a blockdev. |
| 1014 | * If it was not hashed, it will never be added to the dirty list |
| 1015 | * even if it is later hashed, as it will have been marked dirty already. |
| 1016 | * |
| 1017 | * In short, make sure you hash any inodes _before_ you start marking |
| 1018 | * them dirty. |
| 1019 | * |
| 1020 | * This function *must* be atomic for the I_DIRTY_PAGES case - |
| 1021 | * set_page_dirty() is called under spinlock in several places. |
| 1022 | * |
| 1023 | * Note that for blockdevs, inode->dirtied_when represents the dirtying time of |
| 1024 | * the block-special inode (/dev/hda1) itself. And the ->dirtied_when field of |
| 1025 | * the kernel-internal blockdev inode represents the dirtying time of the |
| 1026 | * blockdev's pages. This is why for I_DIRTY_PAGES we always use |
| 1027 | * page->mapping->host, so the page-dirtying time is recorded in the internal |
| 1028 | * blockdev inode. |
| 1029 | */ |
| 1030 | void __mark_inode_dirty(struct inode *inode, int flags) |
| 1031 | { |
| 1032 | struct super_block *sb = inode->i_sb; |
| 1033 | |
| 1034 | /* |
| 1035 | * Don't do this for I_DIRTY_PAGES - that doesn't actually |
| 1036 | * dirty the inode itself |
| 1037 | */ |
| 1038 | if (flags & (I_DIRTY_SYNC | I_DIRTY_DATASYNC)) { |
| 1039 | if (sb->s_op->dirty_inode) |
| 1040 | sb->s_op->dirty_inode(inode); |
| 1041 | } |
| 1042 | |
| 1043 | /* |
| 1044 | * make sure that changes are seen by all cpus before we test i_state |
| 1045 | * -- mikulas |
| 1046 | */ |
| 1047 | smp_mb(); |
| 1048 | |
| 1049 | /* avoid the locking if we can */ |
| 1050 | if ((inode->i_state & flags) == flags) |
| 1051 | return; |
| 1052 | |
| 1053 | if (unlikely(block_dump)) |
| 1054 | block_dump___mark_inode_dirty(inode); |
| 1055 | |
| 1056 | spin_lock(&inode_lock); |
| 1057 | if ((inode->i_state & flags) != flags) { |
| 1058 | const int was_dirty = inode->i_state & I_DIRTY; |
| 1059 | |
| 1060 | inode->i_state |= flags; |
| 1061 | |
| 1062 | /* |
| 1063 | * If the inode is being synced, just update its dirty state. |
| 1064 | * The unlocker will place the inode on the appropriate |
| 1065 | * superblock list, based upon its state. |
| 1066 | */ |
| 1067 | if (inode->i_state & I_SYNC) |
| 1068 | goto out; |
| 1069 | |
| 1070 | /* |
| 1071 | * Only add valid (hashed) inodes to the superblock's |
| 1072 | * dirty list. Add blockdev inodes as well. |
| 1073 | */ |
| 1074 | if (!S_ISBLK(inode->i_mode)) { |
| 1075 | if (hlist_unhashed(&inode->i_hash)) |
| 1076 | goto out; |
| 1077 | } |
| 1078 | if (inode->i_state & (I_FREEING|I_CLEAR)) |
| 1079 | goto out; |
| 1080 | |
| 1081 | /* |
| 1082 | * If the inode was already on b_dirty/b_io/b_more_io, don't |
| 1083 | * reposition it (that would break b_dirty time-ordering). |
| 1084 | */ |
| 1085 | if (!was_dirty) { |
| 1086 | struct bdi_writeback *wb = &inode_to_bdi(inode)->wb; |
Jens Axboe | 500b067 | 2009-09-09 09:10:25 +0200 | [diff] [blame] | 1087 | struct backing_dev_info *bdi = wb->bdi; |
| 1088 | |
| 1089 | if (bdi_cap_writeback_dirty(bdi) && |
| 1090 | !test_bit(BDI_registered, &bdi->state)) { |
| 1091 | WARN_ON(1); |
| 1092 | printk(KERN_ERR "bdi-%s not registered\n", |
| 1093 | bdi->name); |
| 1094 | } |
Jens Axboe | 03ba378 | 2009-09-09 09:08:54 +0200 | [diff] [blame] | 1095 | |
| 1096 | inode->dirtied_when = jiffies; |
| 1097 | list_move(&inode->i_list, &wb->b_dirty); |
| 1098 | } |
| 1099 | } |
| 1100 | out: |
| 1101 | spin_unlock(&inode_lock); |
| 1102 | } |
| 1103 | EXPORT_SYMBOL(__mark_inode_dirty); |
| 1104 | |
Jens Axboe | 66f3b8e | 2009-09-02 09:19:46 +0200 | [diff] [blame] | 1105 | /* |
| 1106 | * Write out a superblock's list of dirty inodes. A wait will be performed |
| 1107 | * upon no inodes, all inodes or the final one, depending upon sync_mode. |
| 1108 | * |
| 1109 | * If older_than_this is non-NULL, then only write out inodes which |
| 1110 | * had their first dirtying at a time earlier than *older_than_this. |
| 1111 | * |
Jens Axboe | 66f3b8e | 2009-09-02 09:19:46 +0200 | [diff] [blame] | 1112 | * If `bdi' is non-zero then we're being asked to writeback a specific queue. |
| 1113 | * This function assumes that the blockdev superblock's inodes are backed by |
| 1114 | * a variety of queues, so all inodes are searched. For other superblocks, |
| 1115 | * assume that all inodes are backed by the same queue. |
| 1116 | * |
Jens Axboe | 66f3b8e | 2009-09-02 09:19:46 +0200 | [diff] [blame] | 1117 | * The inodes to be written are parked on bdi->b_io. They are moved back onto |
| 1118 | * bdi->b_dirty as they are selected for writing. This way, none can be missed |
| 1119 | * on the writer throttling path, and we get decent balancing between many |
| 1120 | * throttled threads: we don't want them all piling up on inode_sync_wait. |
| 1121 | */ |
Jens Axboe | b6e5131 | 2009-09-16 15:13:54 +0200 | [diff] [blame] | 1122 | static void wait_sb_inodes(struct super_block *sb) |
Jens Axboe | 66f3b8e | 2009-09-02 09:19:46 +0200 | [diff] [blame] | 1123 | { |
Jens Axboe | 03ba378 | 2009-09-09 09:08:54 +0200 | [diff] [blame] | 1124 | struct inode *inode, *old_inode = NULL; |
Jens Axboe | 66f3b8e | 2009-09-02 09:19:46 +0200 | [diff] [blame] | 1125 | |
Jens Axboe | 03ba378 | 2009-09-09 09:08:54 +0200 | [diff] [blame] | 1126 | /* |
| 1127 | * We need to be protected against the filesystem going from |
| 1128 | * r/o to r/w or vice versa. |
| 1129 | */ |
Jens Axboe | b6e5131 | 2009-09-16 15:13:54 +0200 | [diff] [blame] | 1130 | WARN_ON(!rwsem_is_locked(&sb->s_umount)); |
Jens Axboe | 66f3b8e | 2009-09-02 09:19:46 +0200 | [diff] [blame] | 1131 | |
Jens Axboe | 03ba378 | 2009-09-09 09:08:54 +0200 | [diff] [blame] | 1132 | spin_lock(&inode_lock); |
| 1133 | |
| 1134 | /* |
| 1135 | * Data integrity sync. Must wait for all pages under writeback, |
| 1136 | * because there may have been pages dirtied before our sync |
| 1137 | * call, but which had writeout started before we write it out. |
| 1138 | * In which case, the inode may not be on the dirty list, but |
| 1139 | * we still have to wait for that writeout. |
| 1140 | */ |
Jens Axboe | b6e5131 | 2009-09-16 15:13:54 +0200 | [diff] [blame] | 1141 | list_for_each_entry(inode, &sb->s_inodes, i_sb_list) { |
Jens Axboe | 03ba378 | 2009-09-09 09:08:54 +0200 | [diff] [blame] | 1142 | struct address_space *mapping; |
| 1143 | |
| 1144 | if (inode->i_state & (I_FREEING|I_CLEAR|I_WILL_FREE|I_NEW)) |
| 1145 | continue; |
| 1146 | mapping = inode->i_mapping; |
| 1147 | if (mapping->nrpages == 0) |
| 1148 | continue; |
| 1149 | __iget(inode); |
| 1150 | spin_unlock(&inode_lock); |
| 1151 | /* |
| 1152 | * We hold a reference to 'inode' so it couldn't have |
| 1153 | * been removed from s_inodes list while we dropped the |
| 1154 | * inode_lock. We cannot iput the inode now as we can |
| 1155 | * be holding the last reference and we cannot iput it |
| 1156 | * under inode_lock. So we keep the reference and iput |
| 1157 | * it later. |
| 1158 | */ |
| 1159 | iput(old_inode); |
| 1160 | old_inode = inode; |
| 1161 | |
| 1162 | filemap_fdatawait(mapping); |
| 1163 | |
| 1164 | cond_resched(); |
Nick Piggin | 38f2197 | 2009-01-06 14:40:25 -0800 | [diff] [blame] | 1165 | |
Jens Axboe | 66f3b8e | 2009-09-02 09:19:46 +0200 | [diff] [blame] | 1166 | spin_lock(&inode_lock); |
Jens Axboe | 66f3b8e | 2009-09-02 09:19:46 +0200 | [diff] [blame] | 1167 | } |
Jens Axboe | 03ba378 | 2009-09-09 09:08:54 +0200 | [diff] [blame] | 1168 | spin_unlock(&inode_lock); |
| 1169 | iput(old_inode); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1170 | } |
| 1171 | |
Jens Axboe | d8a8559 | 2009-09-02 12:34:32 +0200 | [diff] [blame] | 1172 | /** |
| 1173 | * writeback_inodes_sb - writeback dirty inodes from given super_block |
| 1174 | * @sb: the superblock |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1175 | * |
Jens Axboe | d8a8559 | 2009-09-02 12:34:32 +0200 | [diff] [blame] | 1176 | * Start writeback on some inodes on this super_block. No guarantees are made |
| 1177 | * on how many (if any) will be written, and this function does not wait |
| 1178 | * for IO completion of submitted IO. The number of pages submitted is |
| 1179 | * returned. |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1180 | */ |
Jens Axboe | b6e5131 | 2009-09-16 15:13:54 +0200 | [diff] [blame] | 1181 | void writeback_inodes_sb(struct super_block *sb) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1182 | { |
Jens Axboe | d8a8559 | 2009-09-02 12:34:32 +0200 | [diff] [blame] | 1183 | unsigned long nr_dirty = global_page_state(NR_FILE_DIRTY); |
| 1184 | unsigned long nr_unstable = global_page_state(NR_UNSTABLE_NFS); |
| 1185 | long nr_to_write; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1186 | |
Jens Axboe | d8a8559 | 2009-09-02 12:34:32 +0200 | [diff] [blame] | 1187 | nr_to_write = nr_dirty + nr_unstable + |
Nick Piggin | 38f2197 | 2009-01-06 14:40:25 -0800 | [diff] [blame] | 1188 | (inodes_stat.nr_inodes - inodes_stat.nr_unused); |
Nick Piggin | 38f2197 | 2009-01-06 14:40:25 -0800 | [diff] [blame] | 1189 | |
Jens Axboe | a72bfd4 | 2009-09-26 00:07:46 +0200 | [diff] [blame] | 1190 | bdi_start_writeback(sb->s_bdi, sb, nr_to_write); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1191 | } |
Jens Axboe | d8a8559 | 2009-09-02 12:34:32 +0200 | [diff] [blame] | 1192 | EXPORT_SYMBOL(writeback_inodes_sb); |
| 1193 | |
| 1194 | /** |
Eric Sandeen | 17bd55d | 2009-12-23 07:57:07 -0500 | [diff] [blame] | 1195 | * writeback_inodes_sb_if_idle - start writeback if none underway |
| 1196 | * @sb: the superblock |
| 1197 | * |
| 1198 | * Invoke writeback_inodes_sb if no writeback is currently underway. |
| 1199 | * Returns 1 if writeback was started, 0 if not. |
| 1200 | */ |
| 1201 | int writeback_inodes_sb_if_idle(struct super_block *sb) |
| 1202 | { |
| 1203 | if (!writeback_in_progress(sb->s_bdi)) { |
| 1204 | writeback_inodes_sb(sb); |
| 1205 | return 1; |
| 1206 | } else |
| 1207 | return 0; |
| 1208 | } |
| 1209 | EXPORT_SYMBOL(writeback_inodes_sb_if_idle); |
| 1210 | |
| 1211 | /** |
Jens Axboe | d8a8559 | 2009-09-02 12:34:32 +0200 | [diff] [blame] | 1212 | * sync_inodes_sb - sync sb inode pages |
| 1213 | * @sb: the superblock |
| 1214 | * |
| 1215 | * This function writes and waits on any dirty inode belonging to this |
| 1216 | * super_block. The number of pages synced is returned. |
| 1217 | */ |
Jens Axboe | b6e5131 | 2009-09-16 15:13:54 +0200 | [diff] [blame] | 1218 | void sync_inodes_sb(struct super_block *sb) |
Jens Axboe | d8a8559 | 2009-09-02 12:34:32 +0200 | [diff] [blame] | 1219 | { |
Jens Axboe | b6e5131 | 2009-09-16 15:13:54 +0200 | [diff] [blame] | 1220 | bdi_sync_writeback(sb->s_bdi, sb); |
| 1221 | wait_sb_inodes(sb); |
Jens Axboe | d8a8559 | 2009-09-02 12:34:32 +0200 | [diff] [blame] | 1222 | } |
| 1223 | EXPORT_SYMBOL(sync_inodes_sb); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1224 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1225 | /** |
Andrea Arcangeli | 7f04c26 | 2005-10-30 15:03:05 -0800 | [diff] [blame] | 1226 | * write_inode_now - write an inode to disk |
| 1227 | * @inode: inode to write to disk |
| 1228 | * @sync: whether the write should be synchronous or not |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1229 | * |
Andrea Arcangeli | 7f04c26 | 2005-10-30 15:03:05 -0800 | [diff] [blame] | 1230 | * This function commits an inode to disk immediately if it is dirty. This is |
| 1231 | * primarily needed by knfsd. |
| 1232 | * |
| 1233 | * The caller must either have a ref on the inode or must have set I_WILL_FREE. |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1234 | */ |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1235 | int write_inode_now(struct inode *inode, int sync) |
| 1236 | { |
| 1237 | int ret; |
| 1238 | struct writeback_control wbc = { |
| 1239 | .nr_to_write = LONG_MAX, |
Mike Galbraith | 18914b1 | 2008-02-08 04:20:23 -0800 | [diff] [blame] | 1240 | .sync_mode = sync ? WB_SYNC_ALL : WB_SYNC_NONE, |
OGAWA Hirofumi | 111ebb6 | 2006-06-23 02:03:26 -0700 | [diff] [blame] | 1241 | .range_start = 0, |
| 1242 | .range_end = LLONG_MAX, |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1243 | }; |
| 1244 | |
| 1245 | if (!mapping_cap_writeback_dirty(inode->i_mapping)) |
Andrew Morton | 49364ce | 2005-11-07 00:59:15 -0800 | [diff] [blame] | 1246 | wbc.nr_to_write = 0; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1247 | |
| 1248 | might_sleep(); |
| 1249 | spin_lock(&inode_lock); |
Christoph Hellwig | 01c0319 | 2009-06-08 13:35:40 +0200 | [diff] [blame] | 1250 | ret = writeback_single_inode(inode, &wbc); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1251 | spin_unlock(&inode_lock); |
| 1252 | if (sync) |
Joern Engel | 1c0eeaf | 2007-10-16 23:30:44 -0700 | [diff] [blame] | 1253 | inode_sync_wait(inode); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1254 | return ret; |
| 1255 | } |
| 1256 | EXPORT_SYMBOL(write_inode_now); |
| 1257 | |
| 1258 | /** |
| 1259 | * sync_inode - write an inode and its pages to disk. |
| 1260 | * @inode: the inode to sync |
| 1261 | * @wbc: controls the writeback mode |
| 1262 | * |
| 1263 | * sync_inode() will write an inode and its pages to disk. It will also |
| 1264 | * correctly update the inode on its superblock's dirty inode lists and will |
| 1265 | * update inode->i_state. |
| 1266 | * |
| 1267 | * The caller must have a ref on the inode. |
| 1268 | */ |
| 1269 | int sync_inode(struct inode *inode, struct writeback_control *wbc) |
| 1270 | { |
| 1271 | int ret; |
| 1272 | |
| 1273 | spin_lock(&inode_lock); |
Christoph Hellwig | 01c0319 | 2009-06-08 13:35:40 +0200 | [diff] [blame] | 1274 | ret = writeback_single_inode(inode, wbc); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1275 | spin_unlock(&inode_lock); |
| 1276 | return ret; |
| 1277 | } |
| 1278 | EXPORT_SYMBOL(sync_inode); |