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; |
| 44 | int for_kupdate; |
| 45 | int range_cyclic; |
| 46 | }; |
| 47 | |
| 48 | /* |
Jens Axboe | 03ba378 | 2009-09-09 09:08:54 +0200 | [diff] [blame] | 49 | * Work items for the bdi_writeback threads |
Adrian Bunk | f11b00f | 2008-04-29 00:58:56 -0700 | [diff] [blame] | 50 | */ |
Jens Axboe | 03ba378 | 2009-09-09 09:08:54 +0200 | [diff] [blame] | 51 | struct bdi_work { |
| 52 | struct list_head list; |
Jens Axboe | 03ba378 | 2009-09-09 09:08:54 +0200 | [diff] [blame] | 53 | struct rcu_head rcu_head; |
| 54 | |
| 55 | unsigned long seen; |
| 56 | atomic_t pending; |
| 57 | |
Jens Axboe | c4a77a6 | 2009-09-16 15:18:25 +0200 | [diff] [blame] | 58 | struct wb_writeback_args args; |
Jens Axboe | 03ba378 | 2009-09-09 09:08:54 +0200 | [diff] [blame] | 59 | |
| 60 | unsigned long state; |
| 61 | }; |
| 62 | |
| 63 | enum { |
| 64 | WS_USED_B = 0, |
| 65 | WS_ONSTACK_B, |
| 66 | }; |
| 67 | |
| 68 | #define WS_USED (1 << WS_USED_B) |
| 69 | #define WS_ONSTACK (1 << WS_ONSTACK_B) |
| 70 | |
| 71 | static inline bool bdi_work_on_stack(struct bdi_work *work) |
Adrian Bunk | f11b00f | 2008-04-29 00:58:56 -0700 | [diff] [blame] | 72 | { |
Jens Axboe | 03ba378 | 2009-09-09 09:08:54 +0200 | [diff] [blame] | 73 | return test_bit(WS_ONSTACK_B, &work->state); |
| 74 | } |
| 75 | |
| 76 | static inline void bdi_work_init(struct bdi_work *work, |
| 77 | struct writeback_control *wbc) |
| 78 | { |
| 79 | INIT_RCU_HEAD(&work->rcu_head); |
Jens Axboe | c4a77a6 | 2009-09-16 15:18:25 +0200 | [diff] [blame] | 80 | work->args.sb = wbc->sb; |
| 81 | work->args.nr_pages = wbc->nr_to_write; |
| 82 | work->args.sync_mode = wbc->sync_mode; |
| 83 | work->args.range_cyclic = wbc->range_cyclic; |
| 84 | work->args.for_kupdate = 0; |
Jens Axboe | 03ba378 | 2009-09-09 09:08:54 +0200 | [diff] [blame] | 85 | work->state = WS_USED; |
| 86 | } |
| 87 | |
Adrian Bunk | f11b00f | 2008-04-29 00:58:56 -0700 | [diff] [blame] | 88 | /** |
| 89 | * writeback_in_progress - determine whether there is writeback in progress |
| 90 | * @bdi: the device's backing_dev_info structure. |
| 91 | * |
Jens Axboe | 03ba378 | 2009-09-09 09:08:54 +0200 | [diff] [blame] | 92 | * Determine whether there is writeback waiting to be handled against a |
| 93 | * backing device. |
Adrian Bunk | f11b00f | 2008-04-29 00:58:56 -0700 | [diff] [blame] | 94 | */ |
| 95 | int writeback_in_progress(struct backing_dev_info *bdi) |
| 96 | { |
Jens Axboe | 03ba378 | 2009-09-09 09:08:54 +0200 | [diff] [blame] | 97 | return !list_empty(&bdi->work_list); |
Adrian Bunk | f11b00f | 2008-04-29 00:58:56 -0700 | [diff] [blame] | 98 | } |
| 99 | |
Jens Axboe | 03ba378 | 2009-09-09 09:08:54 +0200 | [diff] [blame] | 100 | static void bdi_work_clear(struct bdi_work *work) |
Adrian Bunk | f11b00f | 2008-04-29 00:58:56 -0700 | [diff] [blame] | 101 | { |
Jens Axboe | 03ba378 | 2009-09-09 09:08:54 +0200 | [diff] [blame] | 102 | clear_bit(WS_USED_B, &work->state); |
| 103 | smp_mb__after_clear_bit(); |
| 104 | wake_up_bit(&work->state, WS_USED_B); |
Adrian Bunk | f11b00f | 2008-04-29 00:58:56 -0700 | [diff] [blame] | 105 | } |
| 106 | |
Jens Axboe | 03ba378 | 2009-09-09 09:08:54 +0200 | [diff] [blame] | 107 | static void bdi_work_free(struct rcu_head *head) |
Nick Piggin | 4195f73 | 2009-05-28 09:01:15 +0200 | [diff] [blame] | 108 | { |
Jens Axboe | 03ba378 | 2009-09-09 09:08:54 +0200 | [diff] [blame] | 109 | struct bdi_work *work = container_of(head, struct bdi_work, rcu_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 | if (!bdi_work_on_stack(work)) |
| 112 | kfree(work); |
| 113 | else |
| 114 | bdi_work_clear(work); |
| 115 | } |
| 116 | |
| 117 | static void wb_work_complete(struct bdi_work *work) |
| 118 | { |
Jens Axboe | c4a77a6 | 2009-09-16 15:18:25 +0200 | [diff] [blame] | 119 | const enum writeback_sync_modes sync_mode = work->args.sync_mode; |
Jens Axboe | 03ba378 | 2009-09-09 09:08:54 +0200 | [diff] [blame] | 120 | |
| 121 | /* |
| 122 | * For allocated work, we can clear the done/seen bit right here. |
| 123 | * For on-stack work, we need to postpone both the clear and free |
| 124 | * to after the RCU grace period, since the stack could be invalidated |
| 125 | * as soon as bdi_work_clear() has done the wakeup. |
| 126 | */ |
| 127 | if (!bdi_work_on_stack(work)) |
| 128 | bdi_work_clear(work); |
| 129 | if (sync_mode == WB_SYNC_NONE || bdi_work_on_stack(work)) |
| 130 | call_rcu(&work->rcu_head, bdi_work_free); |
| 131 | } |
| 132 | |
| 133 | static void wb_clear_pending(struct bdi_writeback *wb, struct bdi_work *work) |
| 134 | { |
| 135 | /* |
| 136 | * The caller has retrieved the work arguments from this work, |
| 137 | * drop our reference. If this is the last ref, delete and free it |
| 138 | */ |
| 139 | if (atomic_dec_and_test(&work->pending)) { |
| 140 | struct backing_dev_info *bdi = wb->bdi; |
| 141 | |
| 142 | spin_lock(&bdi->wb_lock); |
| 143 | list_del_rcu(&work->list); |
| 144 | spin_unlock(&bdi->wb_lock); |
| 145 | |
| 146 | wb_work_complete(work); |
Nick Piggin | 4195f73 | 2009-05-28 09:01:15 +0200 | [diff] [blame] | 147 | } |
| 148 | } |
| 149 | |
Jens Axboe | 03ba378 | 2009-09-09 09:08:54 +0200 | [diff] [blame] | 150 | 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] | 151 | { |
Jens Axboe | bcddc3f | 2009-09-13 20:07:36 +0200 | [diff] [blame^] | 152 | work->seen = bdi->wb_mask; |
| 153 | BUG_ON(!work->seen); |
| 154 | atomic_set(&work->pending, bdi->wb_cnt); |
| 155 | BUG_ON(!bdi->wb_cnt); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 156 | |
Jens Axboe | bcddc3f | 2009-09-13 20:07:36 +0200 | [diff] [blame^] | 157 | /* |
| 158 | * Make sure stores are seen before it appears on the list |
| 159 | */ |
| 160 | smp_mb(); |
Jens Axboe | 03ba378 | 2009-09-09 09:08:54 +0200 | [diff] [blame] | 161 | |
Jens Axboe | bcddc3f | 2009-09-13 20:07:36 +0200 | [diff] [blame^] | 162 | spin_lock(&bdi->wb_lock); |
| 163 | list_add_tail_rcu(&work->list, &bdi->work_list); |
| 164 | spin_unlock(&bdi->wb_lock); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 165 | |
| 166 | /* |
Jens Axboe | 03ba378 | 2009-09-09 09:08:54 +0200 | [diff] [blame] | 167 | * If the default thread isn't there, make sure we add it. When |
| 168 | * it gets created and wakes up, we'll run this work. |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 169 | */ |
Jens Axboe | 03ba378 | 2009-09-09 09:08:54 +0200 | [diff] [blame] | 170 | if (unlikely(list_empty_careful(&bdi->wb_list))) |
| 171 | wake_up_process(default_backing_dev_info.wb.task); |
| 172 | else { |
| 173 | struct bdi_writeback *wb = &bdi->wb; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 174 | |
| 175 | /* |
Jens Axboe | bcddc3f | 2009-09-13 20:07:36 +0200 | [diff] [blame^] | 176 | * End work now if this wb has no dirty IO pending. Otherwise |
| 177 | * wakeup the handling thread |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 178 | */ |
Jens Axboe | bcddc3f | 2009-09-13 20:07:36 +0200 | [diff] [blame^] | 179 | if (!wb_has_dirty_io(wb)) |
| 180 | wb_clear_pending(wb, work); |
| 181 | else if (wb->task) |
Jens Axboe | 03ba378 | 2009-09-09 09:08:54 +0200 | [diff] [blame] | 182 | wake_up_process(wb->task); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 183 | } |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 184 | } |
| 185 | |
Jens Axboe | 03ba378 | 2009-09-09 09:08:54 +0200 | [diff] [blame] | 186 | /* |
| 187 | * Used for on-stack allocated work items. The caller needs to wait until |
| 188 | * the wb threads have acked the work before it's safe to continue. |
| 189 | */ |
| 190 | static void bdi_wait_on_work_clear(struct bdi_work *work) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 191 | { |
Jens Axboe | 03ba378 | 2009-09-09 09:08:54 +0200 | [diff] [blame] | 192 | wait_on_bit(&work->state, WS_USED_B, bdi_sched_wait, |
| 193 | TASK_UNINTERRUPTIBLE); |
| 194 | } |
| 195 | |
Jens Axboe | f11fcae | 2009-09-15 09:53:35 +0200 | [diff] [blame] | 196 | static void bdi_alloc_queue_work(struct backing_dev_info *bdi, |
| 197 | struct writeback_control *wbc) |
Jens Axboe | 03ba378 | 2009-09-09 09:08:54 +0200 | [diff] [blame] | 198 | { |
| 199 | struct bdi_work *work; |
| 200 | |
Jens Axboe | bcddc3f | 2009-09-13 20:07:36 +0200 | [diff] [blame^] | 201 | /* |
| 202 | * This is WB_SYNC_NONE writeback, so if allocation fails just |
| 203 | * wakeup the thread for old dirty data writeback |
| 204 | */ |
Jens Axboe | 03ba378 | 2009-09-09 09:08:54 +0200 | [diff] [blame] | 205 | work = kmalloc(sizeof(*work), GFP_ATOMIC); |
Jens Axboe | bcddc3f | 2009-09-13 20:07:36 +0200 | [diff] [blame^] | 206 | if (work) { |
Jens Axboe | 03ba378 | 2009-09-09 09:08:54 +0200 | [diff] [blame] | 207 | bdi_work_init(work, wbc); |
Jens Axboe | bcddc3f | 2009-09-13 20:07:36 +0200 | [diff] [blame^] | 208 | bdi_queue_work(bdi, work); |
| 209 | } else { |
| 210 | struct bdi_writeback *wb = &bdi->wb; |
Jens Axboe | 03ba378 | 2009-09-09 09:08:54 +0200 | [diff] [blame] | 211 | |
Jens Axboe | bcddc3f | 2009-09-13 20:07:36 +0200 | [diff] [blame^] | 212 | if (wb->task) |
| 213 | wake_up_process(wb->task); |
| 214 | } |
Jens Axboe | 03ba378 | 2009-09-09 09:08:54 +0200 | [diff] [blame] | 215 | } |
| 216 | |
| 217 | void bdi_start_writeback(struct writeback_control *wbc) |
| 218 | { |
Jens Axboe | 03ba378 | 2009-09-09 09:08:54 +0200 | [diff] [blame] | 219 | /* |
Christoph Hellwig | f0fad8a | 2009-09-11 09:47:56 +0200 | [diff] [blame] | 220 | * WB_SYNC_NONE is opportunistic writeback. If this allocation fails, |
| 221 | * bdi_queue_work() will wake up the thread and flush old data. This |
| 222 | * should ensure some amount of progress in freeing memory. |
Jens Axboe | 03ba378 | 2009-09-09 09:08:54 +0200 | [diff] [blame] | 223 | */ |
Jens Axboe | f11fcae | 2009-09-15 09:53:35 +0200 | [diff] [blame] | 224 | if (wbc->sync_mode != WB_SYNC_ALL) |
| 225 | bdi_alloc_queue_work(wbc->bdi, wbc); |
| 226 | else { |
Christoph Hellwig | f0fad8a | 2009-09-11 09:47:56 +0200 | [diff] [blame] | 227 | struct bdi_work work; |
| 228 | |
| 229 | bdi_work_init(&work, wbc); |
| 230 | work.state |= WS_ONSTACK; |
| 231 | |
| 232 | bdi_queue_work(wbc->bdi, &work); |
| 233 | bdi_wait_on_work_clear(&work); |
Jens Axboe | 03ba378 | 2009-09-09 09:08:54 +0200 | [diff] [blame] | 234 | } |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 235 | } |
| 236 | |
| 237 | /* |
Andrew Morton | 6610a0b | 2007-10-16 23:30:32 -0700 | [diff] [blame] | 238 | * Redirty an inode: set its when-it-was dirtied timestamp and move it to the |
| 239 | * furthest end of its superblock's dirty-inode list. |
| 240 | * |
| 241 | * 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] | 242 | * 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] | 243 | * the case then the inode must have been redirtied while it was being written |
| 244 | * out and we don't reset its dirtied_when. |
| 245 | */ |
| 246 | static void redirty_tail(struct inode *inode) |
| 247 | { |
Jens Axboe | 03ba378 | 2009-09-09 09:08:54 +0200 | [diff] [blame] | 248 | struct bdi_writeback *wb = &inode_to_bdi(inode)->wb; |
Andrew Morton | 6610a0b | 2007-10-16 23:30:32 -0700 | [diff] [blame] | 249 | |
Jens Axboe | 03ba378 | 2009-09-09 09:08:54 +0200 | [diff] [blame] | 250 | if (!list_empty(&wb->b_dirty)) { |
Jens Axboe | 66f3b8e | 2009-09-02 09:19:46 +0200 | [diff] [blame] | 251 | struct inode *tail; |
Andrew Morton | 6610a0b | 2007-10-16 23:30:32 -0700 | [diff] [blame] | 252 | |
Jens Axboe | 03ba378 | 2009-09-09 09:08:54 +0200 | [diff] [blame] | 253 | tail = list_entry(wb->b_dirty.next, struct inode, i_list); |
Jens Axboe | 66f3b8e | 2009-09-02 09:19:46 +0200 | [diff] [blame] | 254 | if (time_before(inode->dirtied_when, tail->dirtied_when)) |
Andrew Morton | 6610a0b | 2007-10-16 23:30:32 -0700 | [diff] [blame] | 255 | inode->dirtied_when = jiffies; |
| 256 | } |
Jens Axboe | 03ba378 | 2009-09-09 09:08:54 +0200 | [diff] [blame] | 257 | list_move(&inode->i_list, &wb->b_dirty); |
Andrew Morton | 6610a0b | 2007-10-16 23:30:32 -0700 | [diff] [blame] | 258 | } |
| 259 | |
| 260 | /* |
Jens Axboe | 66f3b8e | 2009-09-02 09:19:46 +0200 | [diff] [blame] | 261 | * requeue inode for re-scanning after bdi->b_io list is exhausted. |
Andrew Morton | c986d1e | 2007-10-16 23:30:34 -0700 | [diff] [blame] | 262 | */ |
Ken Chen | 0e0f4fc | 2007-10-16 23:30:38 -0700 | [diff] [blame] | 263 | static void requeue_io(struct inode *inode) |
Andrew Morton | c986d1e | 2007-10-16 23:30:34 -0700 | [diff] [blame] | 264 | { |
Jens Axboe | 03ba378 | 2009-09-09 09:08:54 +0200 | [diff] [blame] | 265 | struct bdi_writeback *wb = &inode_to_bdi(inode)->wb; |
| 266 | |
| 267 | list_move(&inode->i_list, &wb->b_more_io); |
Andrew Morton | c986d1e | 2007-10-16 23:30:34 -0700 | [diff] [blame] | 268 | } |
| 269 | |
Joern Engel | 1c0eeaf | 2007-10-16 23:30:44 -0700 | [diff] [blame] | 270 | static void inode_sync_complete(struct inode *inode) |
| 271 | { |
| 272 | /* |
| 273 | * Prevent speculative execution through spin_unlock(&inode_lock); |
| 274 | */ |
| 275 | smp_mb(); |
| 276 | wake_up_bit(&inode->i_state, __I_SYNC); |
| 277 | } |
| 278 | |
Jeff Layton | d2caa3c5 | 2009-04-02 16:56:37 -0700 | [diff] [blame] | 279 | static bool inode_dirtied_after(struct inode *inode, unsigned long t) |
| 280 | { |
| 281 | bool ret = time_after(inode->dirtied_when, t); |
| 282 | #ifndef CONFIG_64BIT |
| 283 | /* |
| 284 | * For inodes being constantly redirtied, dirtied_when can get stuck. |
| 285 | * It _appears_ to be in the future, but is actually in distant past. |
| 286 | * This test is necessary to prevent such wrapped-around relative times |
| 287 | * from permanently stopping the whole pdflush writeback. |
| 288 | */ |
| 289 | ret = ret && time_before_eq(inode->dirtied_when, jiffies); |
| 290 | #endif |
| 291 | return ret; |
| 292 | } |
| 293 | |
Andrew Morton | c986d1e | 2007-10-16 23:30:34 -0700 | [diff] [blame] | 294 | /* |
Fengguang Wu | 2c13657 | 2007-10-16 23:30:39 -0700 | [diff] [blame] | 295 | * Move expired dirty inodes from @delaying_queue to @dispatch_queue. |
| 296 | */ |
| 297 | static void move_expired_inodes(struct list_head *delaying_queue, |
| 298 | struct list_head *dispatch_queue, |
| 299 | unsigned long *older_than_this) |
| 300 | { |
| 301 | while (!list_empty(delaying_queue)) { |
| 302 | struct inode *inode = list_entry(delaying_queue->prev, |
| 303 | struct inode, i_list); |
| 304 | if (older_than_this && |
Jeff Layton | d2caa3c5 | 2009-04-02 16:56:37 -0700 | [diff] [blame] | 305 | inode_dirtied_after(inode, *older_than_this)) |
Fengguang Wu | 2c13657 | 2007-10-16 23:30:39 -0700 | [diff] [blame] | 306 | break; |
| 307 | list_move(&inode->i_list, dispatch_queue); |
| 308 | } |
| 309 | } |
| 310 | |
| 311 | /* |
| 312 | * Queue all expired dirty inodes for io, eldest first. |
| 313 | */ |
Jens Axboe | 03ba378 | 2009-09-09 09:08:54 +0200 | [diff] [blame] | 314 | 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] | 315 | { |
Jens Axboe | 03ba378 | 2009-09-09 09:08:54 +0200 | [diff] [blame] | 316 | list_splice_init(&wb->b_more_io, wb->b_io.prev); |
| 317 | move_expired_inodes(&wb->b_dirty, &wb->b_io, older_than_this); |
Jens Axboe | 66f3b8e | 2009-09-02 09:19:46 +0200 | [diff] [blame] | 318 | } |
| 319 | |
Jens Axboe | 03ba378 | 2009-09-09 09:08:54 +0200 | [diff] [blame] | 320 | static int write_inode(struct inode *inode, int sync) |
Jens Axboe | 66f3b8e | 2009-09-02 09:19:46 +0200 | [diff] [blame] | 321 | { |
Jens Axboe | 03ba378 | 2009-09-09 09:08:54 +0200 | [diff] [blame] | 322 | if (inode->i_sb->s_op->write_inode && !is_bad_inode(inode)) |
| 323 | return inode->i_sb->s_op->write_inode(inode, sync); |
| 324 | return 0; |
Fengguang Wu | 2c13657 | 2007-10-16 23:30:39 -0700 | [diff] [blame] | 325 | } |
| 326 | |
| 327 | /* |
Christoph Hellwig | 01c0319 | 2009-06-08 13:35:40 +0200 | [diff] [blame] | 328 | * Wait for writeback on an inode to complete. |
| 329 | */ |
| 330 | static void inode_wait_for_writeback(struct inode *inode) |
| 331 | { |
| 332 | DEFINE_WAIT_BIT(wq, &inode->i_state, __I_SYNC); |
| 333 | wait_queue_head_t *wqh; |
| 334 | |
| 335 | wqh = bit_waitqueue(&inode->i_state, __I_SYNC); |
| 336 | do { |
| 337 | spin_unlock(&inode_lock); |
| 338 | __wait_on_bit(wqh, &wq, inode_wait, TASK_UNINTERRUPTIBLE); |
| 339 | spin_lock(&inode_lock); |
| 340 | } while (inode->i_state & I_SYNC); |
| 341 | } |
| 342 | |
| 343 | /* |
| 344 | * Write out an inode's dirty pages. Called under inode_lock. Either the |
| 345 | * caller has ref on the inode (either via __iget or via syscall against an fd) |
| 346 | * or the inode has I_WILL_FREE set (via generic_forget_inode) |
| 347 | * |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 348 | * If `wait' is set, wait on the writeout. |
| 349 | * |
| 350 | * The whole writeout design is quite complex and fragile. We want to avoid |
| 351 | * starvation of particular inodes when others are being redirtied, prevent |
| 352 | * livelocks, etc. |
| 353 | * |
| 354 | * Called under inode_lock. |
| 355 | */ |
| 356 | static int |
Christoph Hellwig | 01c0319 | 2009-06-08 13:35:40 +0200 | [diff] [blame] | 357 | writeback_single_inode(struct inode *inode, struct writeback_control *wbc) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 358 | { |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 359 | struct address_space *mapping = inode->i_mapping; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 360 | int wait = wbc->sync_mode == WB_SYNC_ALL; |
Christoph Hellwig | 01c0319 | 2009-06-08 13:35:40 +0200 | [diff] [blame] | 361 | unsigned dirty; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 362 | int ret; |
| 363 | |
Christoph Hellwig | 01c0319 | 2009-06-08 13:35:40 +0200 | [diff] [blame] | 364 | if (!atomic_read(&inode->i_count)) |
| 365 | WARN_ON(!(inode->i_state & (I_WILL_FREE|I_FREEING))); |
| 366 | else |
| 367 | WARN_ON(inode->i_state & I_WILL_FREE); |
| 368 | |
| 369 | if (inode->i_state & I_SYNC) { |
| 370 | /* |
| 371 | * If this inode is locked for writeback and we are not doing |
Jens Axboe | 66f3b8e | 2009-09-02 09:19:46 +0200 | [diff] [blame] | 372 | * writeback-for-data-integrity, move it to b_more_io so that |
Christoph Hellwig | 01c0319 | 2009-06-08 13:35:40 +0200 | [diff] [blame] | 373 | * writeback can proceed with the other inodes on s_io. |
| 374 | * |
| 375 | * We'll have another go at writing back this inode when we |
Jens Axboe | 66f3b8e | 2009-09-02 09:19:46 +0200 | [diff] [blame] | 376 | * completed a full scan of b_io. |
Christoph Hellwig | 01c0319 | 2009-06-08 13:35:40 +0200 | [diff] [blame] | 377 | */ |
| 378 | if (!wait) { |
| 379 | requeue_io(inode); |
| 380 | return 0; |
| 381 | } |
| 382 | |
| 383 | /* |
| 384 | * It's a data-integrity sync. We must wait. |
| 385 | */ |
| 386 | inode_wait_for_writeback(inode); |
| 387 | } |
| 388 | |
Joern Engel | 1c0eeaf | 2007-10-16 23:30:44 -0700 | [diff] [blame] | 389 | BUG_ON(inode->i_state & I_SYNC); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 390 | |
Joern Engel | 1c0eeaf | 2007-10-16 23:30:44 -0700 | [diff] [blame] | 391 | /* Set I_SYNC, reset I_DIRTY */ |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 392 | dirty = inode->i_state & I_DIRTY; |
Joern Engel | 1c0eeaf | 2007-10-16 23:30:44 -0700 | [diff] [blame] | 393 | inode->i_state |= I_SYNC; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 394 | inode->i_state &= ~I_DIRTY; |
| 395 | |
| 396 | spin_unlock(&inode_lock); |
| 397 | |
| 398 | ret = do_writepages(mapping, wbc); |
| 399 | |
| 400 | /* Don't write the inode if only I_DIRTY_PAGES was set */ |
| 401 | if (dirty & (I_DIRTY_SYNC | I_DIRTY_DATASYNC)) { |
| 402 | int err = write_inode(inode, wait); |
| 403 | if (ret == 0) |
| 404 | ret = err; |
| 405 | } |
| 406 | |
| 407 | if (wait) { |
| 408 | int err = filemap_fdatawait(mapping); |
| 409 | if (ret == 0) |
| 410 | ret = err; |
| 411 | } |
| 412 | |
| 413 | spin_lock(&inode_lock); |
Joern Engel | 1c0eeaf | 2007-10-16 23:30:44 -0700 | [diff] [blame] | 414 | inode->i_state &= ~I_SYNC; |
Wu Fengguang | 84a8924 | 2009-06-16 15:33:17 -0700 | [diff] [blame] | 415 | if (!(inode->i_state & (I_FREEING | I_CLEAR))) { |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 416 | if (!(inode->i_state & I_DIRTY) && |
| 417 | mapping_tagged(mapping, PAGECACHE_TAG_DIRTY)) { |
| 418 | /* |
| 419 | * We didn't write back all the pages. nfs_writepages() |
| 420 | * sometimes bales out without doing anything. Redirty |
Jens Axboe | 66f3b8e | 2009-09-02 09:19:46 +0200 | [diff] [blame] | 421 | * 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] | 422 | */ |
| 423 | /* |
| 424 | * akpm: if the caller was the kupdate function we put |
Jens Axboe | 66f3b8e | 2009-09-02 09:19:46 +0200 | [diff] [blame] | 425 | * this inode at the head of b_dirty so it gets first |
Andrew Morton | 1b43ef9 | 2007-10-16 23:30:35 -0700 | [diff] [blame] | 426 | * consideration. Otherwise, move it to the tail, for |
| 427 | * the reasons described there. I'm not really sure |
| 428 | * how much sense this makes. Presumably I had a good |
| 429 | * reasons for doing it this way, and I'd rather not |
| 430 | * muck with it at present. |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 431 | */ |
| 432 | if (wbc->for_kupdate) { |
| 433 | /* |
Fengguang Wu | 2c13657 | 2007-10-16 23:30:39 -0700 | [diff] [blame] | 434 | * For the kupdate function we move the inode |
Jens Axboe | 66f3b8e | 2009-09-02 09:19:46 +0200 | [diff] [blame] | 435 | * to b_more_io so it will get more writeout as |
Fengguang Wu | 2c13657 | 2007-10-16 23:30:39 -0700 | [diff] [blame] | 436 | * soon as the queue becomes uncongested. |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 437 | */ |
| 438 | inode->i_state |= I_DIRTY_PAGES; |
Fengguang Wu | 8bc3be2 | 2008-02-04 22:29:36 -0800 | [diff] [blame] | 439 | if (wbc->nr_to_write <= 0) { |
| 440 | /* |
| 441 | * slice used up: queue for next turn |
| 442 | */ |
| 443 | requeue_io(inode); |
| 444 | } else { |
| 445 | /* |
| 446 | * somehow blocked: retry later |
| 447 | */ |
| 448 | redirty_tail(inode); |
| 449 | } |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 450 | } else { |
| 451 | /* |
| 452 | * Otherwise fully redirty the inode so that |
| 453 | * other inodes on this superblock will get some |
| 454 | * writeout. Otherwise heavy writing to one |
| 455 | * file would indefinitely suspend writeout of |
| 456 | * all the other files. |
| 457 | */ |
| 458 | inode->i_state |= I_DIRTY_PAGES; |
Andrew Morton | 1b43ef9 | 2007-10-16 23:30:35 -0700 | [diff] [blame] | 459 | redirty_tail(inode); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 460 | } |
| 461 | } else if (inode->i_state & I_DIRTY) { |
| 462 | /* |
| 463 | * Someone redirtied the inode while were writing back |
| 464 | * the pages. |
| 465 | */ |
Andrew Morton | 6610a0b | 2007-10-16 23:30:32 -0700 | [diff] [blame] | 466 | redirty_tail(inode); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 467 | } else if (atomic_read(&inode->i_count)) { |
| 468 | /* |
| 469 | * The inode is clean, inuse |
| 470 | */ |
| 471 | list_move(&inode->i_list, &inode_in_use); |
| 472 | } else { |
| 473 | /* |
| 474 | * The inode is clean, unused |
| 475 | */ |
| 476 | list_move(&inode->i_list, &inode_unused); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 477 | } |
| 478 | } |
Joern Engel | 1c0eeaf | 2007-10-16 23:30:44 -0700 | [diff] [blame] | 479 | inode_sync_complete(inode); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 480 | return ret; |
| 481 | } |
| 482 | |
Jens Axboe | 03ba378 | 2009-09-09 09:08:54 +0200 | [diff] [blame] | 483 | /* |
| 484 | * For WB_SYNC_NONE writeback, the caller does not have the sb pinned |
| 485 | * before calling writeback. So make sure that we do pin it, so it doesn't |
| 486 | * go away while we are writing inodes from it. |
| 487 | * |
| 488 | * Returns 0 if the super was successfully pinned (or pinning wasn't needed), |
| 489 | * 1 if we failed. |
| 490 | */ |
| 491 | static int pin_sb_for_writeback(struct writeback_control *wbc, |
| 492 | struct inode *inode) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 493 | { |
Jens Axboe | 03ba378 | 2009-09-09 09:08:54 +0200 | [diff] [blame] | 494 | struct super_block *sb = inode->i_sb; |
| 495 | |
| 496 | /* |
| 497 | * Caller must already hold the ref for this |
| 498 | */ |
| 499 | if (wbc->sync_mode == WB_SYNC_ALL) { |
| 500 | WARN_ON(!rwsem_is_locked(&sb->s_umount)); |
| 501 | return 0; |
| 502 | } |
| 503 | |
| 504 | spin_lock(&sb_lock); |
| 505 | sb->s_count++; |
| 506 | if (down_read_trylock(&sb->s_umount)) { |
| 507 | if (sb->s_root) { |
| 508 | spin_unlock(&sb_lock); |
| 509 | return 0; |
| 510 | } |
| 511 | /* |
| 512 | * umounted, drop rwsem again and fall through to failure |
| 513 | */ |
| 514 | up_read(&sb->s_umount); |
| 515 | } |
| 516 | |
| 517 | sb->s_count--; |
| 518 | spin_unlock(&sb_lock); |
| 519 | return 1; |
| 520 | } |
| 521 | |
| 522 | static void unpin_sb_for_writeback(struct writeback_control *wbc, |
| 523 | struct inode *inode) |
| 524 | { |
| 525 | struct super_block *sb = inode->i_sb; |
| 526 | |
| 527 | if (wbc->sync_mode == WB_SYNC_ALL) |
| 528 | return; |
| 529 | |
| 530 | up_read(&sb->s_umount); |
| 531 | put_super(sb); |
| 532 | } |
| 533 | |
| 534 | static void writeback_inodes_wb(struct bdi_writeback *wb, |
| 535 | struct writeback_control *wbc) |
| 536 | { |
| 537 | struct super_block *sb = wbc->sb; |
Jens Axboe | 66f3b8e | 2009-09-02 09:19:46 +0200 | [diff] [blame] | 538 | const int is_blkdev_sb = sb_is_blkdev_sb(sb); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 539 | const unsigned long start = jiffies; /* livelock avoidance */ |
| 540 | |
Hans Reiser | ae8547b | 2008-05-07 15:48:57 +0300 | [diff] [blame] | 541 | spin_lock(&inode_lock); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 542 | |
Jens Axboe | 03ba378 | 2009-09-09 09:08:54 +0200 | [diff] [blame] | 543 | if (!wbc->for_kupdate || list_empty(&wb->b_io)) |
| 544 | queue_io(wb, wbc->older_than_this); |
Jens Axboe | 66f3b8e | 2009-09-02 09:19:46 +0200 | [diff] [blame] | 545 | |
Jens Axboe | 03ba378 | 2009-09-09 09:08:54 +0200 | [diff] [blame] | 546 | while (!list_empty(&wb->b_io)) { |
| 547 | struct inode *inode = list_entry(wb->b_io.prev, |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 548 | struct inode, i_list); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 549 | long pages_skipped; |
| 550 | |
Jens Axboe | 66f3b8e | 2009-09-02 09:19:46 +0200 | [diff] [blame] | 551 | /* |
| 552 | * super block given and doesn't match, skip this inode |
| 553 | */ |
| 554 | if (sb && sb != inode->i_sb) { |
| 555 | redirty_tail(inode); |
| 556 | continue; |
| 557 | } |
| 558 | |
Jens Axboe | 03ba378 | 2009-09-09 09:08:54 +0200 | [diff] [blame] | 559 | if (!bdi_cap_writeback_dirty(wb->bdi)) { |
Andrew Morton | 9852a0e7 | 2007-10-16 23:30:33 -0700 | [diff] [blame] | 560 | redirty_tail(inode); |
Jens Axboe | 66f3b8e | 2009-09-02 09:19:46 +0200 | [diff] [blame] | 561 | if (is_blkdev_sb) { |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 562 | /* |
| 563 | * Dirty memory-backed blockdev: the ramdisk |
| 564 | * driver does this. Skip just this inode |
| 565 | */ |
| 566 | continue; |
| 567 | } |
| 568 | /* |
| 569 | * Dirty memory-backed inode against a filesystem other |
| 570 | * than the kernel-internal bdev filesystem. Skip the |
| 571 | * entire superblock. |
| 572 | */ |
| 573 | break; |
| 574 | } |
| 575 | |
Wu Fengguang | 84a8924 | 2009-06-16 15:33:17 -0700 | [diff] [blame] | 576 | if (inode->i_state & (I_NEW | I_WILL_FREE)) { |
Nick Piggin | 7ef0d73 | 2009-03-12 14:31:38 -0700 | [diff] [blame] | 577 | requeue_io(inode); |
| 578 | continue; |
| 579 | } |
| 580 | |
Jens Axboe | 03ba378 | 2009-09-09 09:08:54 +0200 | [diff] [blame] | 581 | if (wbc->nonblocking && bdi_write_congested(wb->bdi)) { |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 582 | wbc->encountered_congestion = 1; |
Jens Axboe | 66f3b8e | 2009-09-02 09:19:46 +0200 | [diff] [blame] | 583 | if (!is_blkdev_sb) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 584 | break; /* Skip a congested fs */ |
Ken Chen | 0e0f4fc | 2007-10-16 23:30:38 -0700 | [diff] [blame] | 585 | requeue_io(inode); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 586 | continue; /* Skip a congested blockdev */ |
| 587 | } |
| 588 | |
Jeff Layton | d2caa3c5 | 2009-04-02 16:56:37 -0700 | [diff] [blame] | 589 | /* |
| 590 | * Was this inode dirtied after sync_sb_inodes was called? |
| 591 | * This keeps sync from extra jobs and livelock. |
| 592 | */ |
| 593 | if (inode_dirtied_after(inode, start)) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 594 | break; |
| 595 | |
Jens Axboe | 03ba378 | 2009-09-09 09:08:54 +0200 | [diff] [blame] | 596 | if (pin_sb_for_writeback(wbc, inode)) { |
| 597 | requeue_io(inode); |
| 598 | continue; |
| 599 | } |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 600 | |
Wu Fengguang | 84a8924 | 2009-06-16 15:33:17 -0700 | [diff] [blame] | 601 | BUG_ON(inode->i_state & (I_FREEING | I_CLEAR)); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 602 | __iget(inode); |
| 603 | pages_skipped = wbc->pages_skipped; |
Christoph Hellwig | 01c0319 | 2009-06-08 13:35:40 +0200 | [diff] [blame] | 604 | writeback_single_inode(inode, wbc); |
Jens Axboe | 03ba378 | 2009-09-09 09:08:54 +0200 | [diff] [blame] | 605 | unpin_sb_for_writeback(wbc, inode); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 606 | if (wbc->pages_skipped != pages_skipped) { |
| 607 | /* |
| 608 | * writeback is not making progress due to locked |
| 609 | * buffers. Skip this inode for now. |
| 610 | */ |
Andrew Morton | f57b9b7 | 2007-10-16 23:30:34 -0700 | [diff] [blame] | 611 | redirty_tail(inode); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 612 | } |
| 613 | spin_unlock(&inode_lock); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 614 | iput(inode); |
OGAWA Hirofumi | 4ffc844 | 2006-03-25 03:07:44 -0800 | [diff] [blame] | 615 | cond_resched(); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 616 | spin_lock(&inode_lock); |
Fengguang Wu | 8bc3be2 | 2008-02-04 22:29:36 -0800 | [diff] [blame] | 617 | if (wbc->nr_to_write <= 0) { |
| 618 | wbc->more_io = 1; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 619 | break; |
Fengguang Wu | 8bc3be2 | 2008-02-04 22:29:36 -0800 | [diff] [blame] | 620 | } |
Jens Axboe | 03ba378 | 2009-09-09 09:08:54 +0200 | [diff] [blame] | 621 | if (!list_empty(&wb->b_more_io)) |
Fengguang Wu | 8bc3be2 | 2008-02-04 22:29:36 -0800 | [diff] [blame] | 622 | wbc->more_io = 1; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 623 | } |
Nick Piggin | 38f2197 | 2009-01-06 14:40:25 -0800 | [diff] [blame] | 624 | |
Jens Axboe | 66f3b8e | 2009-09-02 09:19:46 +0200 | [diff] [blame] | 625 | spin_unlock(&inode_lock); |
| 626 | /* Leave any unwritten inodes on b_io */ |
| 627 | } |
| 628 | |
Jens Axboe | 03ba378 | 2009-09-09 09:08:54 +0200 | [diff] [blame] | 629 | void writeback_inodes_wbc(struct writeback_control *wbc) |
| 630 | { |
| 631 | struct backing_dev_info *bdi = wbc->bdi; |
| 632 | |
| 633 | writeback_inodes_wb(&bdi->wb, wbc); |
| 634 | } |
| 635 | |
| 636 | /* |
| 637 | * The maximum number of pages to writeout in a single bdi flush/kupdate |
| 638 | * operation. We do this so we don't hold I_SYNC against an inode for |
| 639 | * enormous amounts of time, which would block a userspace task which has |
| 640 | * been forced to throttle against that inode. Also, the code reevaluates |
| 641 | * the dirty each time it has written this many pages. |
| 642 | */ |
| 643 | #define MAX_WRITEBACK_PAGES 1024 |
| 644 | |
| 645 | static inline bool over_bground_thresh(void) |
| 646 | { |
| 647 | unsigned long background_thresh, dirty_thresh; |
| 648 | |
| 649 | get_dirty_limits(&background_thresh, &dirty_thresh, NULL, NULL); |
| 650 | |
| 651 | return (global_page_state(NR_FILE_DIRTY) + |
| 652 | global_page_state(NR_UNSTABLE_NFS) >= background_thresh); |
| 653 | } |
| 654 | |
| 655 | /* |
| 656 | * Explicit flushing or periodic writeback of "old" data. |
| 657 | * |
| 658 | * Define "old": the first time one of an inode's pages is dirtied, we mark the |
| 659 | * dirtying-time in the inode's address_space. So this periodic writeback code |
| 660 | * just walks the superblock inode list, writing back any inodes which are |
| 661 | * older than a specific point in time. |
| 662 | * |
| 663 | * Try to run once per dirty_writeback_interval. But if a writeback event |
| 664 | * takes longer than a dirty_writeback_interval interval, then leave a |
| 665 | * one-second gap. |
| 666 | * |
| 667 | * older_than_this takes precedence over nr_to_write. So we'll only write back |
| 668 | * all dirty pages if they are all attached to "old" mappings. |
| 669 | */ |
Jens Axboe | c4a77a6 | 2009-09-16 15:18:25 +0200 | [diff] [blame] | 670 | static long wb_writeback(struct bdi_writeback *wb, |
| 671 | struct wb_writeback_args *args) |
Jens Axboe | 03ba378 | 2009-09-09 09:08:54 +0200 | [diff] [blame] | 672 | { |
| 673 | struct writeback_control wbc = { |
| 674 | .bdi = wb->bdi, |
Jens Axboe | c4a77a6 | 2009-09-16 15:18:25 +0200 | [diff] [blame] | 675 | .sb = args->sb, |
| 676 | .sync_mode = args->sync_mode, |
Jens Axboe | 03ba378 | 2009-09-09 09:08:54 +0200 | [diff] [blame] | 677 | .older_than_this = NULL, |
Jens Axboe | c4a77a6 | 2009-09-16 15:18:25 +0200 | [diff] [blame] | 678 | .for_kupdate = args->for_kupdate, |
| 679 | .range_cyclic = args->range_cyclic, |
Jens Axboe | 03ba378 | 2009-09-09 09:08:54 +0200 | [diff] [blame] | 680 | }; |
| 681 | unsigned long oldest_jif; |
| 682 | long wrote = 0; |
| 683 | |
| 684 | if (wbc.for_kupdate) { |
| 685 | wbc.older_than_this = &oldest_jif; |
| 686 | oldest_jif = jiffies - |
| 687 | msecs_to_jiffies(dirty_expire_interval * 10); |
| 688 | } |
Jens Axboe | c4a77a6 | 2009-09-16 15:18:25 +0200 | [diff] [blame] | 689 | if (!wbc.range_cyclic) { |
| 690 | wbc.range_start = 0; |
| 691 | wbc.range_end = LLONG_MAX; |
| 692 | } |
Jens Axboe | 03ba378 | 2009-09-09 09:08:54 +0200 | [diff] [blame] | 693 | |
| 694 | for (;;) { |
| 695 | /* |
| 696 | * Don't flush anything for non-integrity writeback where |
| 697 | * no nr_pages was given |
| 698 | */ |
Jens Axboe | c4a77a6 | 2009-09-16 15:18:25 +0200 | [diff] [blame] | 699 | if (!args->for_kupdate && args->nr_pages <= 0 && |
| 700 | args->sync_mode == WB_SYNC_NONE) |
Jens Axboe | 03ba378 | 2009-09-09 09:08:54 +0200 | [diff] [blame] | 701 | break; |
| 702 | |
| 703 | /* |
| 704 | * If no specific pages were given and this is just a |
| 705 | * periodic background writeout and we are below the |
| 706 | * background dirty threshold, don't do anything |
| 707 | */ |
Jens Axboe | c4a77a6 | 2009-09-16 15:18:25 +0200 | [diff] [blame] | 708 | if (args->for_kupdate && args->nr_pages <= 0 && |
| 709 | !over_bground_thresh()) |
Jens Axboe | 03ba378 | 2009-09-09 09:08:54 +0200 | [diff] [blame] | 710 | break; |
| 711 | |
| 712 | wbc.more_io = 0; |
| 713 | wbc.encountered_congestion = 0; |
| 714 | wbc.nr_to_write = MAX_WRITEBACK_PAGES; |
| 715 | wbc.pages_skipped = 0; |
| 716 | writeback_inodes_wb(wb, &wbc); |
Jens Axboe | c4a77a6 | 2009-09-16 15:18:25 +0200 | [diff] [blame] | 717 | args->nr_pages -= MAX_WRITEBACK_PAGES - wbc.nr_to_write; |
Jens Axboe | 03ba378 | 2009-09-09 09:08:54 +0200 | [diff] [blame] | 718 | wrote += MAX_WRITEBACK_PAGES - wbc.nr_to_write; |
| 719 | |
| 720 | /* |
| 721 | * If we ran out of stuff to write, bail unless more_io got set |
| 722 | */ |
| 723 | if (wbc.nr_to_write > 0 || wbc.pages_skipped > 0) { |
| 724 | if (wbc.more_io && !wbc.for_kupdate) |
| 725 | continue; |
| 726 | break; |
| 727 | } |
| 728 | } |
| 729 | |
| 730 | return wrote; |
| 731 | } |
| 732 | |
| 733 | /* |
| 734 | * Return the next bdi_work struct that hasn't been processed by this |
| 735 | * wb thread yet |
| 736 | */ |
| 737 | static struct bdi_work *get_next_work_item(struct backing_dev_info *bdi, |
| 738 | struct bdi_writeback *wb) |
| 739 | { |
| 740 | struct bdi_work *work, *ret = NULL; |
| 741 | |
| 742 | rcu_read_lock(); |
| 743 | |
| 744 | list_for_each_entry_rcu(work, &bdi->work_list, list) { |
| 745 | if (!test_and_clear_bit(wb->nr, &work->seen)) |
| 746 | continue; |
| 747 | |
| 748 | ret = work; |
| 749 | break; |
| 750 | } |
| 751 | |
| 752 | rcu_read_unlock(); |
| 753 | return ret; |
| 754 | } |
| 755 | |
| 756 | static long wb_check_old_data_flush(struct bdi_writeback *wb) |
| 757 | { |
| 758 | unsigned long expired; |
| 759 | long nr_pages; |
| 760 | |
| 761 | expired = wb->last_old_flush + |
| 762 | msecs_to_jiffies(dirty_writeback_interval * 10); |
| 763 | if (time_before(jiffies, expired)) |
| 764 | return 0; |
| 765 | |
| 766 | wb->last_old_flush = jiffies; |
| 767 | nr_pages = global_page_state(NR_FILE_DIRTY) + |
| 768 | global_page_state(NR_UNSTABLE_NFS) + |
| 769 | (inodes_stat.nr_inodes - inodes_stat.nr_unused); |
| 770 | |
Jens Axboe | c4a77a6 | 2009-09-16 15:18:25 +0200 | [diff] [blame] | 771 | if (nr_pages) { |
| 772 | struct wb_writeback_args args = { |
| 773 | .nr_pages = nr_pages, |
| 774 | .sync_mode = WB_SYNC_NONE, |
| 775 | .for_kupdate = 1, |
| 776 | .range_cyclic = 1, |
| 777 | }; |
| 778 | |
| 779 | return wb_writeback(wb, &args); |
| 780 | } |
Jens Axboe | 03ba378 | 2009-09-09 09:08:54 +0200 | [diff] [blame] | 781 | |
| 782 | return 0; |
| 783 | } |
| 784 | |
| 785 | /* |
| 786 | * Retrieve work items and do the writeback they describe |
| 787 | */ |
| 788 | long wb_do_writeback(struct bdi_writeback *wb, int force_wait) |
| 789 | { |
| 790 | struct backing_dev_info *bdi = wb->bdi; |
| 791 | struct bdi_work *work; |
Jens Axboe | c4a77a6 | 2009-09-16 15:18:25 +0200 | [diff] [blame] | 792 | long wrote = 0; |
Jens Axboe | 03ba378 | 2009-09-09 09:08:54 +0200 | [diff] [blame] | 793 | |
| 794 | while ((work = get_next_work_item(bdi, wb)) != NULL) { |
Jens Axboe | c4a77a6 | 2009-09-16 15:18:25 +0200 | [diff] [blame] | 795 | struct wb_writeback_args args = work->args; |
Jens Axboe | 03ba378 | 2009-09-09 09:08:54 +0200 | [diff] [blame] | 796 | |
| 797 | /* |
| 798 | * Override sync mode, in case we must wait for completion |
| 799 | */ |
| 800 | if (force_wait) |
Jens Axboe | c4a77a6 | 2009-09-16 15:18:25 +0200 | [diff] [blame] | 801 | work->args.sync_mode = args.sync_mode = WB_SYNC_ALL; |
Jens Axboe | 03ba378 | 2009-09-09 09:08:54 +0200 | [diff] [blame] | 802 | |
| 803 | /* |
| 804 | * If this isn't a data integrity operation, just notify |
| 805 | * that we have seen this work and we are now starting it. |
| 806 | */ |
Jens Axboe | c4a77a6 | 2009-09-16 15:18:25 +0200 | [diff] [blame] | 807 | if (args.sync_mode == WB_SYNC_NONE) |
Jens Axboe | 03ba378 | 2009-09-09 09:08:54 +0200 | [diff] [blame] | 808 | wb_clear_pending(wb, work); |
| 809 | |
Jens Axboe | c4a77a6 | 2009-09-16 15:18:25 +0200 | [diff] [blame] | 810 | wrote += wb_writeback(wb, &args); |
Jens Axboe | 03ba378 | 2009-09-09 09:08:54 +0200 | [diff] [blame] | 811 | |
| 812 | /* |
| 813 | * This is a data integrity writeback, so only do the |
| 814 | * notification when we have completed the work. |
| 815 | */ |
Jens Axboe | c4a77a6 | 2009-09-16 15:18:25 +0200 | [diff] [blame] | 816 | if (args.sync_mode == WB_SYNC_ALL) |
Jens Axboe | 03ba378 | 2009-09-09 09:08:54 +0200 | [diff] [blame] | 817 | wb_clear_pending(wb, work); |
| 818 | } |
| 819 | |
| 820 | /* |
| 821 | * Check for periodic writeback, kupdated() style |
| 822 | */ |
| 823 | wrote += wb_check_old_data_flush(wb); |
| 824 | |
| 825 | return wrote; |
| 826 | } |
| 827 | |
| 828 | /* |
| 829 | * Handle writeback of dirty data for the device backed by this bdi. Also |
| 830 | * wakes up periodically and does kupdated style flushing. |
| 831 | */ |
| 832 | int bdi_writeback_task(struct bdi_writeback *wb) |
| 833 | { |
| 834 | unsigned long last_active = jiffies; |
| 835 | unsigned long wait_jiffies = -1UL; |
| 836 | long pages_written; |
| 837 | |
| 838 | while (!kthread_should_stop()) { |
| 839 | pages_written = wb_do_writeback(wb, 0); |
| 840 | |
| 841 | if (pages_written) |
| 842 | last_active = jiffies; |
| 843 | else if (wait_jiffies != -1UL) { |
| 844 | unsigned long max_idle; |
| 845 | |
| 846 | /* |
| 847 | * Longest period of inactivity that we tolerate. If we |
| 848 | * see dirty data again later, the task will get |
| 849 | * recreated automatically. |
| 850 | */ |
| 851 | max_idle = max(5UL * 60 * HZ, wait_jiffies); |
| 852 | if (time_after(jiffies, max_idle + last_active)) |
| 853 | break; |
| 854 | } |
| 855 | |
| 856 | wait_jiffies = msecs_to_jiffies(dirty_writeback_interval * 10); |
| 857 | set_current_state(TASK_INTERRUPTIBLE); |
| 858 | schedule_timeout(wait_jiffies); |
| 859 | try_to_freeze(); |
| 860 | } |
| 861 | |
| 862 | return 0; |
| 863 | } |
| 864 | |
| 865 | /* |
Jens Axboe | f11fcae | 2009-09-15 09:53:35 +0200 | [diff] [blame] | 866 | * Schedule writeback for all backing devices. Can only be used for |
| 867 | * WB_SYNC_NONE writeback, WB_SYNC_ALL should use bdi_start_writeback() |
| 868 | * and pass in the superblock. |
Jens Axboe | 03ba378 | 2009-09-09 09:08:54 +0200 | [diff] [blame] | 869 | */ |
| 870 | static void bdi_writeback_all(struct writeback_control *wbc) |
| 871 | { |
Jens Axboe | 03ba378 | 2009-09-09 09:08:54 +0200 | [diff] [blame] | 872 | struct backing_dev_info *bdi; |
Jens Axboe | 03ba378 | 2009-09-09 09:08:54 +0200 | [diff] [blame] | 873 | |
Jens Axboe | f11fcae | 2009-09-15 09:53:35 +0200 | [diff] [blame] | 874 | WARN_ON(wbc->sync_mode == WB_SYNC_ALL); |
| 875 | |
Jens Axboe | cfc4ba5 | 2009-09-14 13:12:40 +0200 | [diff] [blame] | 876 | rcu_read_lock(); |
Jens Axboe | 03ba378 | 2009-09-09 09:08:54 +0200 | [diff] [blame] | 877 | |
Jens Axboe | cfc4ba5 | 2009-09-14 13:12:40 +0200 | [diff] [blame] | 878 | list_for_each_entry_rcu(bdi, &bdi_list, bdi_list) { |
Jens Axboe | 03ba378 | 2009-09-09 09:08:54 +0200 | [diff] [blame] | 879 | if (!bdi_has_dirty_io(bdi)) |
| 880 | continue; |
| 881 | |
Jens Axboe | f11fcae | 2009-09-15 09:53:35 +0200 | [diff] [blame] | 882 | bdi_alloc_queue_work(bdi, wbc); |
Jens Axboe | 03ba378 | 2009-09-09 09:08:54 +0200 | [diff] [blame] | 883 | } |
| 884 | |
Jens Axboe | cfc4ba5 | 2009-09-14 13:12:40 +0200 | [diff] [blame] | 885 | rcu_read_unlock(); |
Jens Axboe | 03ba378 | 2009-09-09 09:08:54 +0200 | [diff] [blame] | 886 | } |
| 887 | |
| 888 | /* |
| 889 | * Start writeback of `nr_pages' pages. If `nr_pages' is zero, write back |
| 890 | * the whole world. |
| 891 | */ |
| 892 | void wakeup_flusher_threads(long nr_pages) |
| 893 | { |
| 894 | struct writeback_control wbc = { |
| 895 | .sync_mode = WB_SYNC_NONE, |
| 896 | .older_than_this = NULL, |
| 897 | .range_cyclic = 1, |
| 898 | }; |
| 899 | |
| 900 | if (nr_pages == 0) |
| 901 | nr_pages = global_page_state(NR_FILE_DIRTY) + |
| 902 | global_page_state(NR_UNSTABLE_NFS); |
| 903 | wbc.nr_to_write = nr_pages; |
| 904 | bdi_writeback_all(&wbc); |
| 905 | } |
| 906 | |
| 907 | static noinline void block_dump___mark_inode_dirty(struct inode *inode) |
| 908 | { |
| 909 | if (inode->i_ino || strcmp(inode->i_sb->s_id, "bdev")) { |
| 910 | struct dentry *dentry; |
| 911 | const char *name = "?"; |
| 912 | |
| 913 | dentry = d_find_alias(inode); |
| 914 | if (dentry) { |
| 915 | spin_lock(&dentry->d_lock); |
| 916 | name = (const char *) dentry->d_name.name; |
| 917 | } |
| 918 | printk(KERN_DEBUG |
| 919 | "%s(%d): dirtied inode %lu (%s) on %s\n", |
| 920 | current->comm, task_pid_nr(current), inode->i_ino, |
| 921 | name, inode->i_sb->s_id); |
| 922 | if (dentry) { |
| 923 | spin_unlock(&dentry->d_lock); |
| 924 | dput(dentry); |
| 925 | } |
| 926 | } |
| 927 | } |
| 928 | |
| 929 | /** |
| 930 | * __mark_inode_dirty - internal function |
| 931 | * @inode: inode to mark |
| 932 | * @flags: what kind of dirty (i.e. I_DIRTY_SYNC) |
| 933 | * Mark an inode as dirty. Callers should use mark_inode_dirty or |
| 934 | * mark_inode_dirty_sync. |
| 935 | * |
| 936 | * Put the inode on the super block's dirty list. |
| 937 | * |
| 938 | * CAREFUL! We mark it dirty unconditionally, but move it onto the |
| 939 | * dirty list only if it is hashed or if it refers to a blockdev. |
| 940 | * If it was not hashed, it will never be added to the dirty list |
| 941 | * even if it is later hashed, as it will have been marked dirty already. |
| 942 | * |
| 943 | * In short, make sure you hash any inodes _before_ you start marking |
| 944 | * them dirty. |
| 945 | * |
| 946 | * This function *must* be atomic for the I_DIRTY_PAGES case - |
| 947 | * set_page_dirty() is called under spinlock in several places. |
| 948 | * |
| 949 | * Note that for blockdevs, inode->dirtied_when represents the dirtying time of |
| 950 | * the block-special inode (/dev/hda1) itself. And the ->dirtied_when field of |
| 951 | * the kernel-internal blockdev inode represents the dirtying time of the |
| 952 | * blockdev's pages. This is why for I_DIRTY_PAGES we always use |
| 953 | * page->mapping->host, so the page-dirtying time is recorded in the internal |
| 954 | * blockdev inode. |
| 955 | */ |
| 956 | void __mark_inode_dirty(struct inode *inode, int flags) |
| 957 | { |
| 958 | struct super_block *sb = inode->i_sb; |
| 959 | |
| 960 | /* |
| 961 | * Don't do this for I_DIRTY_PAGES - that doesn't actually |
| 962 | * dirty the inode itself |
| 963 | */ |
| 964 | if (flags & (I_DIRTY_SYNC | I_DIRTY_DATASYNC)) { |
| 965 | if (sb->s_op->dirty_inode) |
| 966 | sb->s_op->dirty_inode(inode); |
| 967 | } |
| 968 | |
| 969 | /* |
| 970 | * make sure that changes are seen by all cpus before we test i_state |
| 971 | * -- mikulas |
| 972 | */ |
| 973 | smp_mb(); |
| 974 | |
| 975 | /* avoid the locking if we can */ |
| 976 | if ((inode->i_state & flags) == flags) |
| 977 | return; |
| 978 | |
| 979 | if (unlikely(block_dump)) |
| 980 | block_dump___mark_inode_dirty(inode); |
| 981 | |
| 982 | spin_lock(&inode_lock); |
| 983 | if ((inode->i_state & flags) != flags) { |
| 984 | const int was_dirty = inode->i_state & I_DIRTY; |
| 985 | |
| 986 | inode->i_state |= flags; |
| 987 | |
| 988 | /* |
| 989 | * If the inode is being synced, just update its dirty state. |
| 990 | * The unlocker will place the inode on the appropriate |
| 991 | * superblock list, based upon its state. |
| 992 | */ |
| 993 | if (inode->i_state & I_SYNC) |
| 994 | goto out; |
| 995 | |
| 996 | /* |
| 997 | * Only add valid (hashed) inodes to the superblock's |
| 998 | * dirty list. Add blockdev inodes as well. |
| 999 | */ |
| 1000 | if (!S_ISBLK(inode->i_mode)) { |
| 1001 | if (hlist_unhashed(&inode->i_hash)) |
| 1002 | goto out; |
| 1003 | } |
| 1004 | if (inode->i_state & (I_FREEING|I_CLEAR)) |
| 1005 | goto out; |
| 1006 | |
| 1007 | /* |
| 1008 | * If the inode was already on b_dirty/b_io/b_more_io, don't |
| 1009 | * reposition it (that would break b_dirty time-ordering). |
| 1010 | */ |
| 1011 | if (!was_dirty) { |
| 1012 | struct bdi_writeback *wb = &inode_to_bdi(inode)->wb; |
Jens Axboe | 500b067 | 2009-09-09 09:10:25 +0200 | [diff] [blame] | 1013 | struct backing_dev_info *bdi = wb->bdi; |
| 1014 | |
| 1015 | if (bdi_cap_writeback_dirty(bdi) && |
| 1016 | !test_bit(BDI_registered, &bdi->state)) { |
| 1017 | WARN_ON(1); |
| 1018 | printk(KERN_ERR "bdi-%s not registered\n", |
| 1019 | bdi->name); |
| 1020 | } |
Jens Axboe | 03ba378 | 2009-09-09 09:08:54 +0200 | [diff] [blame] | 1021 | |
| 1022 | inode->dirtied_when = jiffies; |
| 1023 | list_move(&inode->i_list, &wb->b_dirty); |
| 1024 | } |
| 1025 | } |
| 1026 | out: |
| 1027 | spin_unlock(&inode_lock); |
| 1028 | } |
| 1029 | EXPORT_SYMBOL(__mark_inode_dirty); |
| 1030 | |
Jens Axboe | 66f3b8e | 2009-09-02 09:19:46 +0200 | [diff] [blame] | 1031 | /* |
| 1032 | * Write out a superblock's list of dirty inodes. A wait will be performed |
| 1033 | * upon no inodes, all inodes or the final one, depending upon sync_mode. |
| 1034 | * |
| 1035 | * If older_than_this is non-NULL, then only write out inodes which |
| 1036 | * had their first dirtying at a time earlier than *older_than_this. |
| 1037 | * |
| 1038 | * If we're a pdlfush thread, then implement pdflush collision avoidance |
| 1039 | * against the entire list. |
| 1040 | * |
| 1041 | * If `bdi' is non-zero then we're being asked to writeback a specific queue. |
| 1042 | * This function assumes that the blockdev superblock's inodes are backed by |
| 1043 | * a variety of queues, so all inodes are searched. For other superblocks, |
| 1044 | * assume that all inodes are backed by the same queue. |
| 1045 | * |
Jens Axboe | 66f3b8e | 2009-09-02 09:19:46 +0200 | [diff] [blame] | 1046 | * The inodes to be written are parked on bdi->b_io. They are moved back onto |
| 1047 | * bdi->b_dirty as they are selected for writing. This way, none can be missed |
| 1048 | * on the writer throttling path, and we get decent balancing between many |
| 1049 | * throttled threads: we don't want them all piling up on inode_sync_wait. |
| 1050 | */ |
Jens Axboe | 03ba378 | 2009-09-09 09:08:54 +0200 | [diff] [blame] | 1051 | static void wait_sb_inodes(struct writeback_control *wbc) |
Jens Axboe | 66f3b8e | 2009-09-02 09:19:46 +0200 | [diff] [blame] | 1052 | { |
Jens Axboe | 03ba378 | 2009-09-09 09:08:54 +0200 | [diff] [blame] | 1053 | struct inode *inode, *old_inode = NULL; |
Jens Axboe | 66f3b8e | 2009-09-02 09:19:46 +0200 | [diff] [blame] | 1054 | |
Jens Axboe | 03ba378 | 2009-09-09 09:08:54 +0200 | [diff] [blame] | 1055 | /* |
| 1056 | * We need to be protected against the filesystem going from |
| 1057 | * r/o to r/w or vice versa. |
| 1058 | */ |
| 1059 | WARN_ON(!rwsem_is_locked(&wbc->sb->s_umount)); |
Jens Axboe | 66f3b8e | 2009-09-02 09:19:46 +0200 | [diff] [blame] | 1060 | |
Jens Axboe | 03ba378 | 2009-09-09 09:08:54 +0200 | [diff] [blame] | 1061 | spin_lock(&inode_lock); |
| 1062 | |
| 1063 | /* |
| 1064 | * Data integrity sync. Must wait for all pages under writeback, |
| 1065 | * because there may have been pages dirtied before our sync |
| 1066 | * call, but which had writeout started before we write it out. |
| 1067 | * In which case, the inode may not be on the dirty list, but |
| 1068 | * we still have to wait for that writeout. |
| 1069 | */ |
| 1070 | list_for_each_entry(inode, &wbc->sb->s_inodes, i_sb_list) { |
| 1071 | struct address_space *mapping; |
| 1072 | |
| 1073 | if (inode->i_state & (I_FREEING|I_CLEAR|I_WILL_FREE|I_NEW)) |
| 1074 | continue; |
| 1075 | mapping = inode->i_mapping; |
| 1076 | if (mapping->nrpages == 0) |
| 1077 | continue; |
| 1078 | __iget(inode); |
| 1079 | spin_unlock(&inode_lock); |
| 1080 | /* |
| 1081 | * We hold a reference to 'inode' so it couldn't have |
| 1082 | * been removed from s_inodes list while we dropped the |
| 1083 | * inode_lock. We cannot iput the inode now as we can |
| 1084 | * be holding the last reference and we cannot iput it |
| 1085 | * under inode_lock. So we keep the reference and iput |
| 1086 | * it later. |
| 1087 | */ |
| 1088 | iput(old_inode); |
| 1089 | old_inode = inode; |
| 1090 | |
| 1091 | filemap_fdatawait(mapping); |
| 1092 | |
| 1093 | cond_resched(); |
Nick Piggin | 38f2197 | 2009-01-06 14:40:25 -0800 | [diff] [blame] | 1094 | |
Jens Axboe | 66f3b8e | 2009-09-02 09:19:46 +0200 | [diff] [blame] | 1095 | spin_lock(&inode_lock); |
Jens Axboe | 66f3b8e | 2009-09-02 09:19:46 +0200 | [diff] [blame] | 1096 | } |
Jens Axboe | 03ba378 | 2009-09-09 09:08:54 +0200 | [diff] [blame] | 1097 | spin_unlock(&inode_lock); |
| 1098 | iput(old_inode); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1099 | } |
| 1100 | |
Jens Axboe | d8a8559 | 2009-09-02 12:34:32 +0200 | [diff] [blame] | 1101 | /** |
| 1102 | * writeback_inodes_sb - writeback dirty inodes from given super_block |
| 1103 | * @sb: the superblock |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1104 | * |
Jens Axboe | d8a8559 | 2009-09-02 12:34:32 +0200 | [diff] [blame] | 1105 | * Start writeback on some inodes on this super_block. No guarantees are made |
| 1106 | * on how many (if any) will be written, and this function does not wait |
| 1107 | * for IO completion of submitted IO. The number of pages submitted is |
| 1108 | * returned. |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1109 | */ |
Jens Axboe | d8a8559 | 2009-09-02 12:34:32 +0200 | [diff] [blame] | 1110 | long writeback_inodes_sb(struct super_block *sb) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1111 | { |
| 1112 | struct writeback_control wbc = { |
Jens Axboe | 03ba378 | 2009-09-09 09:08:54 +0200 | [diff] [blame] | 1113 | .sb = sb, |
Jens Axboe | d8a8559 | 2009-09-02 12:34:32 +0200 | [diff] [blame] | 1114 | .sync_mode = WB_SYNC_NONE, |
OGAWA Hirofumi | 111ebb6 | 2006-06-23 02:03:26 -0700 | [diff] [blame] | 1115 | .range_start = 0, |
| 1116 | .range_end = LLONG_MAX, |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1117 | }; |
Jens Axboe | d8a8559 | 2009-09-02 12:34:32 +0200 | [diff] [blame] | 1118 | unsigned long nr_dirty = global_page_state(NR_FILE_DIRTY); |
| 1119 | unsigned long nr_unstable = global_page_state(NR_UNSTABLE_NFS); |
| 1120 | long nr_to_write; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1121 | |
Jens Axboe | d8a8559 | 2009-09-02 12:34:32 +0200 | [diff] [blame] | 1122 | nr_to_write = nr_dirty + nr_unstable + |
Nick Piggin | 38f2197 | 2009-01-06 14:40:25 -0800 | [diff] [blame] | 1123 | (inodes_stat.nr_inodes - inodes_stat.nr_unused); |
Nick Piggin | 38f2197 | 2009-01-06 14:40:25 -0800 | [diff] [blame] | 1124 | |
Jens Axboe | d8a8559 | 2009-09-02 12:34:32 +0200 | [diff] [blame] | 1125 | wbc.nr_to_write = nr_to_write; |
Jens Axboe | 03ba378 | 2009-09-09 09:08:54 +0200 | [diff] [blame] | 1126 | bdi_writeback_all(&wbc); |
Jens Axboe | d8a8559 | 2009-09-02 12:34:32 +0200 | [diff] [blame] | 1127 | return nr_to_write - wbc.nr_to_write; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1128 | } |
Jens Axboe | d8a8559 | 2009-09-02 12:34:32 +0200 | [diff] [blame] | 1129 | EXPORT_SYMBOL(writeback_inodes_sb); |
| 1130 | |
| 1131 | /** |
| 1132 | * sync_inodes_sb - sync sb inode pages |
| 1133 | * @sb: the superblock |
| 1134 | * |
| 1135 | * This function writes and waits on any dirty inode belonging to this |
| 1136 | * super_block. The number of pages synced is returned. |
| 1137 | */ |
| 1138 | long sync_inodes_sb(struct super_block *sb) |
| 1139 | { |
| 1140 | struct writeback_control wbc = { |
Jens Axboe | 03ba378 | 2009-09-09 09:08:54 +0200 | [diff] [blame] | 1141 | .sb = sb, |
Jens Axboe | f11fcae | 2009-09-15 09:53:35 +0200 | [diff] [blame] | 1142 | .bdi = sb->s_bdi, |
Jens Axboe | d8a8559 | 2009-09-02 12:34:32 +0200 | [diff] [blame] | 1143 | .sync_mode = WB_SYNC_ALL, |
| 1144 | .range_start = 0, |
| 1145 | .range_end = LLONG_MAX, |
| 1146 | }; |
| 1147 | long nr_to_write = LONG_MAX; /* doesn't actually matter */ |
| 1148 | |
| 1149 | wbc.nr_to_write = nr_to_write; |
Jens Axboe | f11fcae | 2009-09-15 09:53:35 +0200 | [diff] [blame] | 1150 | bdi_start_writeback(&wbc); |
Jens Axboe | 03ba378 | 2009-09-09 09:08:54 +0200 | [diff] [blame] | 1151 | wait_sb_inodes(&wbc); |
Jens Axboe | d8a8559 | 2009-09-02 12:34:32 +0200 | [diff] [blame] | 1152 | return nr_to_write - wbc.nr_to_write; |
| 1153 | } |
| 1154 | EXPORT_SYMBOL(sync_inodes_sb); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1155 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1156 | /** |
Andrea Arcangeli | 7f04c26 | 2005-10-30 15:03:05 -0800 | [diff] [blame] | 1157 | * write_inode_now - write an inode to disk |
| 1158 | * @inode: inode to write to disk |
| 1159 | * @sync: whether the write should be synchronous or not |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1160 | * |
Andrea Arcangeli | 7f04c26 | 2005-10-30 15:03:05 -0800 | [diff] [blame] | 1161 | * This function commits an inode to disk immediately if it is dirty. This is |
| 1162 | * primarily needed by knfsd. |
| 1163 | * |
| 1164 | * 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] | 1165 | */ |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1166 | int write_inode_now(struct inode *inode, int sync) |
| 1167 | { |
| 1168 | int ret; |
| 1169 | struct writeback_control wbc = { |
| 1170 | .nr_to_write = LONG_MAX, |
Mike Galbraith | 18914b1 | 2008-02-08 04:20:23 -0800 | [diff] [blame] | 1171 | .sync_mode = sync ? WB_SYNC_ALL : WB_SYNC_NONE, |
OGAWA Hirofumi | 111ebb6 | 2006-06-23 02:03:26 -0700 | [diff] [blame] | 1172 | .range_start = 0, |
| 1173 | .range_end = LLONG_MAX, |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1174 | }; |
| 1175 | |
| 1176 | if (!mapping_cap_writeback_dirty(inode->i_mapping)) |
Andrew Morton | 49364ce | 2005-11-07 00:59:15 -0800 | [diff] [blame] | 1177 | wbc.nr_to_write = 0; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1178 | |
| 1179 | might_sleep(); |
| 1180 | spin_lock(&inode_lock); |
Christoph Hellwig | 01c0319 | 2009-06-08 13:35:40 +0200 | [diff] [blame] | 1181 | ret = writeback_single_inode(inode, &wbc); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1182 | spin_unlock(&inode_lock); |
| 1183 | if (sync) |
Joern Engel | 1c0eeaf | 2007-10-16 23:30:44 -0700 | [diff] [blame] | 1184 | inode_sync_wait(inode); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1185 | return ret; |
| 1186 | } |
| 1187 | EXPORT_SYMBOL(write_inode_now); |
| 1188 | |
| 1189 | /** |
| 1190 | * sync_inode - write an inode and its pages to disk. |
| 1191 | * @inode: the inode to sync |
| 1192 | * @wbc: controls the writeback mode |
| 1193 | * |
| 1194 | * sync_inode() will write an inode and its pages to disk. It will also |
| 1195 | * correctly update the inode on its superblock's dirty inode lists and will |
| 1196 | * update inode->i_state. |
| 1197 | * |
| 1198 | * The caller must have a ref on the inode. |
| 1199 | */ |
| 1200 | int sync_inode(struct inode *inode, struct writeback_control *wbc) |
| 1201 | { |
| 1202 | int ret; |
| 1203 | |
| 1204 | spin_lock(&inode_lock); |
Christoph Hellwig | 01c0319 | 2009-06-08 13:35:40 +0200 | [diff] [blame] | 1205 | ret = writeback_single_inode(inode, wbc); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1206 | spin_unlock(&inode_lock); |
| 1207 | return ret; |
| 1208 | } |
| 1209 | EXPORT_SYMBOL(sync_inode); |