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 { |
Jens Axboe | 8010c3b | 2009-09-15 20:04:57 +0200 | [diff] [blame^] | 52 | struct list_head list; /* pending work list */ |
| 53 | struct rcu_head rcu_head; /* for RCU free/clear of work */ |
Jens Axboe | 03ba378 | 2009-09-09 09:08:54 +0200 | [diff] [blame] | 54 | |
Jens Axboe | 8010c3b | 2009-09-15 20:04:57 +0200 | [diff] [blame^] | 55 | unsigned long seen; /* threads that have seen this work */ |
| 56 | atomic_t pending; /* number of threads still to do work */ |
Jens Axboe | 03ba378 | 2009-09-09 09:08:54 +0200 | [diff] [blame] | 57 | |
Jens Axboe | 8010c3b | 2009-09-15 20:04:57 +0200 | [diff] [blame^] | 58 | struct wb_writeback_args args; /* writeback arguments */ |
Jens Axboe | 03ba378 | 2009-09-09 09:08:54 +0200 | [diff] [blame] | 59 | |
Jens Axboe | 8010c3b | 2009-09-15 20:04:57 +0200 | [diff] [blame^] | 60 | unsigned long state; /* flag bits, see WS_* */ |
Jens Axboe | 03ba378 | 2009-09-09 09:08:54 +0200 | [diff] [blame] | 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, |
Jens Axboe | b6e5131 | 2009-09-16 15:13:54 +0200 | [diff] [blame] | 77 | struct wb_writeback_args *args) |
Jens Axboe | 03ba378 | 2009-09-09 09:08:54 +0200 | [diff] [blame] | 78 | { |
| 79 | INIT_RCU_HEAD(&work->rcu_head); |
Jens Axboe | b6e5131 | 2009-09-16 15:13:54 +0200 | [diff] [blame] | 80 | work->args = *args; |
Jens Axboe | 03ba378 | 2009-09-09 09:08:54 +0200 | [diff] [blame] | 81 | work->state = WS_USED; |
| 82 | } |
| 83 | |
Adrian Bunk | f11b00f | 2008-04-29 00:58:56 -0700 | [diff] [blame] | 84 | /** |
| 85 | * writeback_in_progress - determine whether there is writeback in progress |
| 86 | * @bdi: the device's backing_dev_info structure. |
| 87 | * |
Jens Axboe | 03ba378 | 2009-09-09 09:08:54 +0200 | [diff] [blame] | 88 | * Determine whether there is writeback waiting to be handled against a |
| 89 | * backing device. |
Adrian Bunk | f11b00f | 2008-04-29 00:58:56 -0700 | [diff] [blame] | 90 | */ |
| 91 | int writeback_in_progress(struct backing_dev_info *bdi) |
| 92 | { |
Jens Axboe | 03ba378 | 2009-09-09 09:08:54 +0200 | [diff] [blame] | 93 | return !list_empty(&bdi->work_list); |
Adrian Bunk | f11b00f | 2008-04-29 00:58:56 -0700 | [diff] [blame] | 94 | } |
| 95 | |
Jens Axboe | 03ba378 | 2009-09-09 09:08:54 +0200 | [diff] [blame] | 96 | static void bdi_work_clear(struct bdi_work *work) |
Adrian Bunk | f11b00f | 2008-04-29 00:58:56 -0700 | [diff] [blame] | 97 | { |
Jens Axboe | 03ba378 | 2009-09-09 09:08:54 +0200 | [diff] [blame] | 98 | clear_bit(WS_USED_B, &work->state); |
| 99 | smp_mb__after_clear_bit(); |
| 100 | wake_up_bit(&work->state, WS_USED_B); |
Adrian Bunk | f11b00f | 2008-04-29 00:58:56 -0700 | [diff] [blame] | 101 | } |
| 102 | |
Jens Axboe | 03ba378 | 2009-09-09 09:08:54 +0200 | [diff] [blame] | 103 | static void bdi_work_free(struct rcu_head *head) |
Nick Piggin | 4195f73 | 2009-05-28 09:01:15 +0200 | [diff] [blame] | 104 | { |
Jens Axboe | 03ba378 | 2009-09-09 09:08:54 +0200 | [diff] [blame] | 105 | struct bdi_work *work = container_of(head, struct bdi_work, rcu_head); |
Nick Piggin | 4195f73 | 2009-05-28 09:01:15 +0200 | [diff] [blame] | 106 | |
Jens Axboe | 03ba378 | 2009-09-09 09:08:54 +0200 | [diff] [blame] | 107 | if (!bdi_work_on_stack(work)) |
| 108 | kfree(work); |
| 109 | else |
| 110 | bdi_work_clear(work); |
| 111 | } |
| 112 | |
| 113 | static void wb_work_complete(struct bdi_work *work) |
| 114 | { |
Jens Axboe | c4a77a6 | 2009-09-16 15:18:25 +0200 | [diff] [blame] | 115 | const enum writeback_sync_modes sync_mode = work->args.sync_mode; |
Jens Axboe | 03ba378 | 2009-09-09 09:08:54 +0200 | [diff] [blame] | 116 | |
| 117 | /* |
| 118 | * For allocated work, we can clear the done/seen bit right here. |
| 119 | * For on-stack work, we need to postpone both the clear and free |
| 120 | * to after the RCU grace period, since the stack could be invalidated |
| 121 | * as soon as bdi_work_clear() has done the wakeup. |
| 122 | */ |
| 123 | if (!bdi_work_on_stack(work)) |
| 124 | bdi_work_clear(work); |
| 125 | if (sync_mode == WB_SYNC_NONE || bdi_work_on_stack(work)) |
| 126 | call_rcu(&work->rcu_head, bdi_work_free); |
| 127 | } |
| 128 | |
| 129 | static void wb_clear_pending(struct bdi_writeback *wb, struct bdi_work *work) |
| 130 | { |
| 131 | /* |
| 132 | * The caller has retrieved the work arguments from this work, |
| 133 | * drop our reference. If this is the last ref, delete and free it |
| 134 | */ |
| 135 | if (atomic_dec_and_test(&work->pending)) { |
| 136 | struct backing_dev_info *bdi = wb->bdi; |
| 137 | |
| 138 | spin_lock(&bdi->wb_lock); |
| 139 | list_del_rcu(&work->list); |
| 140 | spin_unlock(&bdi->wb_lock); |
| 141 | |
| 142 | wb_work_complete(work); |
Nick Piggin | 4195f73 | 2009-05-28 09:01:15 +0200 | [diff] [blame] | 143 | } |
| 144 | } |
| 145 | |
Jens Axboe | 03ba378 | 2009-09-09 09:08:54 +0200 | [diff] [blame] | 146 | 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] | 147 | { |
Jens Axboe | bcddc3f | 2009-09-13 20:07:36 +0200 | [diff] [blame] | 148 | work->seen = bdi->wb_mask; |
| 149 | BUG_ON(!work->seen); |
| 150 | atomic_set(&work->pending, bdi->wb_cnt); |
| 151 | BUG_ON(!bdi->wb_cnt); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 152 | |
Jens Axboe | bcddc3f | 2009-09-13 20:07:36 +0200 | [diff] [blame] | 153 | /* |
| 154 | * Make sure stores are seen before it appears on the list |
| 155 | */ |
| 156 | smp_mb(); |
Jens Axboe | 03ba378 | 2009-09-09 09:08:54 +0200 | [diff] [blame] | 157 | |
Jens Axboe | bcddc3f | 2009-09-13 20:07:36 +0200 | [diff] [blame] | 158 | spin_lock(&bdi->wb_lock); |
| 159 | list_add_tail_rcu(&work->list, &bdi->work_list); |
| 160 | spin_unlock(&bdi->wb_lock); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 161 | |
| 162 | /* |
Jens Axboe | 03ba378 | 2009-09-09 09:08:54 +0200 | [diff] [blame] | 163 | * If the default thread isn't there, make sure we add it. When |
| 164 | * it gets created and wakes up, we'll run this work. |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 165 | */ |
Jens Axboe | 03ba378 | 2009-09-09 09:08:54 +0200 | [diff] [blame] | 166 | if (unlikely(list_empty_careful(&bdi->wb_list))) |
| 167 | wake_up_process(default_backing_dev_info.wb.task); |
| 168 | else { |
| 169 | struct bdi_writeback *wb = &bdi->wb; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 170 | |
| 171 | /* |
Jens Axboe | bcddc3f | 2009-09-13 20:07:36 +0200 | [diff] [blame] | 172 | * End work now if this wb has no dirty IO pending. Otherwise |
| 173 | * wakeup the handling thread |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 174 | */ |
Jens Axboe | bcddc3f | 2009-09-13 20:07:36 +0200 | [diff] [blame] | 175 | if (!wb_has_dirty_io(wb)) |
| 176 | wb_clear_pending(wb, work); |
| 177 | else if (wb->task) |
Jens Axboe | 03ba378 | 2009-09-09 09:08:54 +0200 | [diff] [blame] | 178 | wake_up_process(wb->task); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 179 | } |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 180 | } |
| 181 | |
Jens Axboe | 03ba378 | 2009-09-09 09:08:54 +0200 | [diff] [blame] | 182 | /* |
| 183 | * Used for on-stack allocated work items. The caller needs to wait until |
| 184 | * the wb threads have acked the work before it's safe to continue. |
| 185 | */ |
| 186 | static void bdi_wait_on_work_clear(struct bdi_work *work) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 187 | { |
Jens Axboe | 03ba378 | 2009-09-09 09:08:54 +0200 | [diff] [blame] | 188 | wait_on_bit(&work->state, WS_USED_B, bdi_sched_wait, |
| 189 | TASK_UNINTERRUPTIBLE); |
| 190 | } |
| 191 | |
Jens Axboe | f11fcae | 2009-09-15 09:53:35 +0200 | [diff] [blame] | 192 | static void bdi_alloc_queue_work(struct backing_dev_info *bdi, |
Jens Axboe | b6e5131 | 2009-09-16 15:13:54 +0200 | [diff] [blame] | 193 | struct wb_writeback_args *args) |
Jens Axboe | 03ba378 | 2009-09-09 09:08:54 +0200 | [diff] [blame] | 194 | { |
| 195 | struct bdi_work *work; |
| 196 | |
Jens Axboe | bcddc3f | 2009-09-13 20:07:36 +0200 | [diff] [blame] | 197 | /* |
| 198 | * This is WB_SYNC_NONE writeback, so if allocation fails just |
| 199 | * wakeup the thread for old dirty data writeback |
| 200 | */ |
Jens Axboe | 03ba378 | 2009-09-09 09:08:54 +0200 | [diff] [blame] | 201 | work = kmalloc(sizeof(*work), GFP_ATOMIC); |
Jens Axboe | bcddc3f | 2009-09-13 20:07:36 +0200 | [diff] [blame] | 202 | if (work) { |
Jens Axboe | b6e5131 | 2009-09-16 15:13:54 +0200 | [diff] [blame] | 203 | bdi_work_init(work, args); |
Jens Axboe | bcddc3f | 2009-09-13 20:07:36 +0200 | [diff] [blame] | 204 | bdi_queue_work(bdi, work); |
| 205 | } else { |
| 206 | struct bdi_writeback *wb = &bdi->wb; |
Jens Axboe | 03ba378 | 2009-09-09 09:08:54 +0200 | [diff] [blame] | 207 | |
Jens Axboe | bcddc3f | 2009-09-13 20:07:36 +0200 | [diff] [blame] | 208 | if (wb->task) |
| 209 | wake_up_process(wb->task); |
| 210 | } |
Jens Axboe | 03ba378 | 2009-09-09 09:08:54 +0200 | [diff] [blame] | 211 | } |
| 212 | |
Jens Axboe | b6e5131 | 2009-09-16 15:13:54 +0200 | [diff] [blame] | 213 | /** |
| 214 | * bdi_sync_writeback - start and wait for writeback |
| 215 | * @bdi: the backing device to write from |
| 216 | * @sb: write inodes from this super_block |
| 217 | * |
| 218 | * Description: |
| 219 | * This does WB_SYNC_ALL data integrity writeback and waits for the |
| 220 | * IO to complete. Callers must hold the sb s_umount semaphore for |
| 221 | * reading, to avoid having the super disappear before we are done. |
| 222 | */ |
| 223 | static void bdi_sync_writeback(struct backing_dev_info *bdi, |
| 224 | struct super_block *sb) |
Jens Axboe | 03ba378 | 2009-09-09 09:08:54 +0200 | [diff] [blame] | 225 | { |
Jens Axboe | b6e5131 | 2009-09-16 15:13:54 +0200 | [diff] [blame] | 226 | struct wb_writeback_args args = { |
| 227 | .sb = sb, |
| 228 | .sync_mode = WB_SYNC_ALL, |
| 229 | .nr_pages = LONG_MAX, |
| 230 | .range_cyclic = 0, |
| 231 | }; |
| 232 | struct bdi_work work; |
Christoph Hellwig | f0fad8a | 2009-09-11 09:47:56 +0200 | [diff] [blame] | 233 | |
Jens Axboe | b6e5131 | 2009-09-16 15:13:54 +0200 | [diff] [blame] | 234 | bdi_work_init(&work, &args); |
| 235 | work.state |= WS_ONSTACK; |
Christoph Hellwig | f0fad8a | 2009-09-11 09:47:56 +0200 | [diff] [blame] | 236 | |
Jens Axboe | b6e5131 | 2009-09-16 15:13:54 +0200 | [diff] [blame] | 237 | bdi_queue_work(bdi, &work); |
| 238 | bdi_wait_on_work_clear(&work); |
| 239 | } |
| 240 | |
| 241 | /** |
| 242 | * bdi_start_writeback - start writeback |
| 243 | * @bdi: the backing device to write from |
| 244 | * @nr_pages: the number of pages to write |
| 245 | * |
| 246 | * Description: |
| 247 | * This does WB_SYNC_NONE opportunistic writeback. The IO is only |
| 248 | * started when this function returns, we make no guarentees on |
| 249 | * completion. Caller need not hold sb s_umount semaphore. |
| 250 | * |
| 251 | */ |
| 252 | void bdi_start_writeback(struct backing_dev_info *bdi, long nr_pages) |
| 253 | { |
| 254 | struct wb_writeback_args args = { |
| 255 | .sync_mode = WB_SYNC_NONE, |
| 256 | .nr_pages = nr_pages, |
| 257 | .range_cyclic = 1, |
| 258 | }; |
| 259 | |
| 260 | bdi_alloc_queue_work(bdi, &args); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 261 | } |
| 262 | |
| 263 | /* |
Andrew Morton | 6610a0b | 2007-10-16 23:30:32 -0700 | [diff] [blame] | 264 | * Redirty an inode: set its when-it-was dirtied timestamp and move it to the |
| 265 | * furthest end of its superblock's dirty-inode list. |
| 266 | * |
| 267 | * 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] | 268 | * 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] | 269 | * the case then the inode must have been redirtied while it was being written |
| 270 | * out and we don't reset its dirtied_when. |
| 271 | */ |
| 272 | static void redirty_tail(struct inode *inode) |
| 273 | { |
Jens Axboe | 03ba378 | 2009-09-09 09:08:54 +0200 | [diff] [blame] | 274 | struct bdi_writeback *wb = &inode_to_bdi(inode)->wb; |
Andrew Morton | 6610a0b | 2007-10-16 23:30:32 -0700 | [diff] [blame] | 275 | |
Jens Axboe | 03ba378 | 2009-09-09 09:08:54 +0200 | [diff] [blame] | 276 | if (!list_empty(&wb->b_dirty)) { |
Jens Axboe | 66f3b8e | 2009-09-02 09:19:46 +0200 | [diff] [blame] | 277 | struct inode *tail; |
Andrew Morton | 6610a0b | 2007-10-16 23:30:32 -0700 | [diff] [blame] | 278 | |
Jens Axboe | 03ba378 | 2009-09-09 09:08:54 +0200 | [diff] [blame] | 279 | tail = list_entry(wb->b_dirty.next, struct inode, i_list); |
Jens Axboe | 66f3b8e | 2009-09-02 09:19:46 +0200 | [diff] [blame] | 280 | if (time_before(inode->dirtied_when, tail->dirtied_when)) |
Andrew Morton | 6610a0b | 2007-10-16 23:30:32 -0700 | [diff] [blame] | 281 | inode->dirtied_when = jiffies; |
| 282 | } |
Jens Axboe | 03ba378 | 2009-09-09 09:08:54 +0200 | [diff] [blame] | 283 | list_move(&inode->i_list, &wb->b_dirty); |
Andrew Morton | 6610a0b | 2007-10-16 23:30:32 -0700 | [diff] [blame] | 284 | } |
| 285 | |
| 286 | /* |
Jens Axboe | 66f3b8e | 2009-09-02 09:19:46 +0200 | [diff] [blame] | 287 | * requeue inode for re-scanning after bdi->b_io list is exhausted. |
Andrew Morton | c986d1e | 2007-10-16 23:30:34 -0700 | [diff] [blame] | 288 | */ |
Ken Chen | 0e0f4fc | 2007-10-16 23:30:38 -0700 | [diff] [blame] | 289 | static void requeue_io(struct inode *inode) |
Andrew Morton | c986d1e | 2007-10-16 23:30:34 -0700 | [diff] [blame] | 290 | { |
Jens Axboe | 03ba378 | 2009-09-09 09:08:54 +0200 | [diff] [blame] | 291 | struct bdi_writeback *wb = &inode_to_bdi(inode)->wb; |
| 292 | |
| 293 | list_move(&inode->i_list, &wb->b_more_io); |
Andrew Morton | c986d1e | 2007-10-16 23:30:34 -0700 | [diff] [blame] | 294 | } |
| 295 | |
Joern Engel | 1c0eeaf | 2007-10-16 23:30:44 -0700 | [diff] [blame] | 296 | static void inode_sync_complete(struct inode *inode) |
| 297 | { |
| 298 | /* |
| 299 | * Prevent speculative execution through spin_unlock(&inode_lock); |
| 300 | */ |
| 301 | smp_mb(); |
| 302 | wake_up_bit(&inode->i_state, __I_SYNC); |
| 303 | } |
| 304 | |
Jeff Layton | d2caa3c5 | 2009-04-02 16:56:37 -0700 | [diff] [blame] | 305 | static bool inode_dirtied_after(struct inode *inode, unsigned long t) |
| 306 | { |
| 307 | bool ret = time_after(inode->dirtied_when, t); |
| 308 | #ifndef CONFIG_64BIT |
| 309 | /* |
| 310 | * For inodes being constantly redirtied, dirtied_when can get stuck. |
| 311 | * It _appears_ to be in the future, but is actually in distant past. |
| 312 | * This test is necessary to prevent such wrapped-around relative times |
| 313 | * from permanently stopping the whole pdflush writeback. |
| 314 | */ |
| 315 | ret = ret && time_before_eq(inode->dirtied_when, jiffies); |
| 316 | #endif |
| 317 | return ret; |
| 318 | } |
| 319 | |
Andrew Morton | c986d1e | 2007-10-16 23:30:34 -0700 | [diff] [blame] | 320 | /* |
Fengguang Wu | 2c13657 | 2007-10-16 23:30:39 -0700 | [diff] [blame] | 321 | * Move expired dirty inodes from @delaying_queue to @dispatch_queue. |
| 322 | */ |
| 323 | static void move_expired_inodes(struct list_head *delaying_queue, |
| 324 | struct list_head *dispatch_queue, |
| 325 | unsigned long *older_than_this) |
| 326 | { |
| 327 | while (!list_empty(delaying_queue)) { |
| 328 | struct inode *inode = list_entry(delaying_queue->prev, |
| 329 | struct inode, i_list); |
| 330 | if (older_than_this && |
Jeff Layton | d2caa3c5 | 2009-04-02 16:56:37 -0700 | [diff] [blame] | 331 | inode_dirtied_after(inode, *older_than_this)) |
Fengguang Wu | 2c13657 | 2007-10-16 23:30:39 -0700 | [diff] [blame] | 332 | break; |
| 333 | list_move(&inode->i_list, dispatch_queue); |
| 334 | } |
| 335 | } |
| 336 | |
| 337 | /* |
| 338 | * Queue all expired dirty inodes for io, eldest first. |
| 339 | */ |
Jens Axboe | 03ba378 | 2009-09-09 09:08:54 +0200 | [diff] [blame] | 340 | 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] | 341 | { |
Jens Axboe | 03ba378 | 2009-09-09 09:08:54 +0200 | [diff] [blame] | 342 | list_splice_init(&wb->b_more_io, wb->b_io.prev); |
| 343 | move_expired_inodes(&wb->b_dirty, &wb->b_io, older_than_this); |
Jens Axboe | 66f3b8e | 2009-09-02 09:19:46 +0200 | [diff] [blame] | 344 | } |
| 345 | |
Jens Axboe | 03ba378 | 2009-09-09 09:08:54 +0200 | [diff] [blame] | 346 | static int write_inode(struct inode *inode, int sync) |
Jens Axboe | 66f3b8e | 2009-09-02 09:19:46 +0200 | [diff] [blame] | 347 | { |
Jens Axboe | 03ba378 | 2009-09-09 09:08:54 +0200 | [diff] [blame] | 348 | if (inode->i_sb->s_op->write_inode && !is_bad_inode(inode)) |
| 349 | return inode->i_sb->s_op->write_inode(inode, sync); |
| 350 | return 0; |
Fengguang Wu | 2c13657 | 2007-10-16 23:30:39 -0700 | [diff] [blame] | 351 | } |
| 352 | |
| 353 | /* |
Christoph Hellwig | 01c0319 | 2009-06-08 13:35:40 +0200 | [diff] [blame] | 354 | * Wait for writeback on an inode to complete. |
| 355 | */ |
| 356 | static void inode_wait_for_writeback(struct inode *inode) |
| 357 | { |
| 358 | DEFINE_WAIT_BIT(wq, &inode->i_state, __I_SYNC); |
| 359 | wait_queue_head_t *wqh; |
| 360 | |
| 361 | wqh = bit_waitqueue(&inode->i_state, __I_SYNC); |
| 362 | do { |
| 363 | spin_unlock(&inode_lock); |
| 364 | __wait_on_bit(wqh, &wq, inode_wait, TASK_UNINTERRUPTIBLE); |
| 365 | spin_lock(&inode_lock); |
| 366 | } while (inode->i_state & I_SYNC); |
| 367 | } |
| 368 | |
| 369 | /* |
| 370 | * Write out an inode's dirty pages. Called under inode_lock. Either the |
| 371 | * caller has ref on the inode (either via __iget or via syscall against an fd) |
| 372 | * or the inode has I_WILL_FREE set (via generic_forget_inode) |
| 373 | * |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 374 | * If `wait' is set, wait on the writeout. |
| 375 | * |
| 376 | * The whole writeout design is quite complex and fragile. We want to avoid |
| 377 | * starvation of particular inodes when others are being redirtied, prevent |
| 378 | * livelocks, etc. |
| 379 | * |
| 380 | * Called under inode_lock. |
| 381 | */ |
| 382 | static int |
Christoph Hellwig | 01c0319 | 2009-06-08 13:35:40 +0200 | [diff] [blame] | 383 | writeback_single_inode(struct inode *inode, struct writeback_control *wbc) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 384 | { |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 385 | struct address_space *mapping = inode->i_mapping; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 386 | int wait = wbc->sync_mode == WB_SYNC_ALL; |
Christoph Hellwig | 01c0319 | 2009-06-08 13:35:40 +0200 | [diff] [blame] | 387 | unsigned dirty; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 388 | int ret; |
| 389 | |
Christoph Hellwig | 01c0319 | 2009-06-08 13:35:40 +0200 | [diff] [blame] | 390 | if (!atomic_read(&inode->i_count)) |
| 391 | WARN_ON(!(inode->i_state & (I_WILL_FREE|I_FREEING))); |
| 392 | else |
| 393 | WARN_ON(inode->i_state & I_WILL_FREE); |
| 394 | |
| 395 | if (inode->i_state & I_SYNC) { |
| 396 | /* |
| 397 | * If this inode is locked for writeback and we are not doing |
Jens Axboe | 66f3b8e | 2009-09-02 09:19:46 +0200 | [diff] [blame] | 398 | * writeback-for-data-integrity, move it to b_more_io so that |
Christoph Hellwig | 01c0319 | 2009-06-08 13:35:40 +0200 | [diff] [blame] | 399 | * writeback can proceed with the other inodes on s_io. |
| 400 | * |
| 401 | * We'll have another go at writing back this inode when we |
Jens Axboe | 66f3b8e | 2009-09-02 09:19:46 +0200 | [diff] [blame] | 402 | * completed a full scan of b_io. |
Christoph Hellwig | 01c0319 | 2009-06-08 13:35:40 +0200 | [diff] [blame] | 403 | */ |
| 404 | if (!wait) { |
| 405 | requeue_io(inode); |
| 406 | return 0; |
| 407 | } |
| 408 | |
| 409 | /* |
| 410 | * It's a data-integrity sync. We must wait. |
| 411 | */ |
| 412 | inode_wait_for_writeback(inode); |
| 413 | } |
| 414 | |
Joern Engel | 1c0eeaf | 2007-10-16 23:30:44 -0700 | [diff] [blame] | 415 | BUG_ON(inode->i_state & I_SYNC); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 416 | |
Joern Engel | 1c0eeaf | 2007-10-16 23:30:44 -0700 | [diff] [blame] | 417 | /* Set I_SYNC, reset I_DIRTY */ |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 418 | dirty = inode->i_state & I_DIRTY; |
Joern Engel | 1c0eeaf | 2007-10-16 23:30:44 -0700 | [diff] [blame] | 419 | inode->i_state |= I_SYNC; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 420 | inode->i_state &= ~I_DIRTY; |
| 421 | |
| 422 | spin_unlock(&inode_lock); |
| 423 | |
| 424 | ret = do_writepages(mapping, wbc); |
| 425 | |
| 426 | /* Don't write the inode if only I_DIRTY_PAGES was set */ |
| 427 | if (dirty & (I_DIRTY_SYNC | I_DIRTY_DATASYNC)) { |
| 428 | int err = write_inode(inode, wait); |
| 429 | if (ret == 0) |
| 430 | ret = err; |
| 431 | } |
| 432 | |
| 433 | if (wait) { |
| 434 | int err = filemap_fdatawait(mapping); |
| 435 | if (ret == 0) |
| 436 | ret = err; |
| 437 | } |
| 438 | |
| 439 | spin_lock(&inode_lock); |
Joern Engel | 1c0eeaf | 2007-10-16 23:30:44 -0700 | [diff] [blame] | 440 | inode->i_state &= ~I_SYNC; |
Wu Fengguang | 84a8924 | 2009-06-16 15:33:17 -0700 | [diff] [blame] | 441 | if (!(inode->i_state & (I_FREEING | I_CLEAR))) { |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 442 | if (!(inode->i_state & I_DIRTY) && |
| 443 | mapping_tagged(mapping, PAGECACHE_TAG_DIRTY)) { |
| 444 | /* |
| 445 | * We didn't write back all the pages. nfs_writepages() |
| 446 | * sometimes bales out without doing anything. Redirty |
Jens Axboe | 66f3b8e | 2009-09-02 09:19:46 +0200 | [diff] [blame] | 447 | * 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] | 448 | */ |
| 449 | /* |
| 450 | * akpm: if the caller was the kupdate function we put |
Jens Axboe | 66f3b8e | 2009-09-02 09:19:46 +0200 | [diff] [blame] | 451 | * this inode at the head of b_dirty so it gets first |
Andrew Morton | 1b43ef9 | 2007-10-16 23:30:35 -0700 | [diff] [blame] | 452 | * consideration. Otherwise, move it to the tail, for |
| 453 | * the reasons described there. I'm not really sure |
| 454 | * how much sense this makes. Presumably I had a good |
| 455 | * reasons for doing it this way, and I'd rather not |
| 456 | * muck with it at present. |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 457 | */ |
| 458 | if (wbc->for_kupdate) { |
| 459 | /* |
Fengguang Wu | 2c13657 | 2007-10-16 23:30:39 -0700 | [diff] [blame] | 460 | * For the kupdate function we move the inode |
Jens Axboe | 66f3b8e | 2009-09-02 09:19:46 +0200 | [diff] [blame] | 461 | * to b_more_io so it will get more writeout as |
Fengguang Wu | 2c13657 | 2007-10-16 23:30:39 -0700 | [diff] [blame] | 462 | * soon as the queue becomes uncongested. |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 463 | */ |
| 464 | inode->i_state |= I_DIRTY_PAGES; |
Fengguang Wu | 8bc3be2 | 2008-02-04 22:29:36 -0800 | [diff] [blame] | 465 | if (wbc->nr_to_write <= 0) { |
| 466 | /* |
| 467 | * slice used up: queue for next turn |
| 468 | */ |
| 469 | requeue_io(inode); |
| 470 | } else { |
| 471 | /* |
| 472 | * somehow blocked: retry later |
| 473 | */ |
| 474 | redirty_tail(inode); |
| 475 | } |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 476 | } else { |
| 477 | /* |
| 478 | * Otherwise fully redirty the inode so that |
| 479 | * other inodes on this superblock will get some |
| 480 | * writeout. Otherwise heavy writing to one |
| 481 | * file would indefinitely suspend writeout of |
| 482 | * all the other files. |
| 483 | */ |
| 484 | inode->i_state |= I_DIRTY_PAGES; |
Andrew Morton | 1b43ef9 | 2007-10-16 23:30:35 -0700 | [diff] [blame] | 485 | redirty_tail(inode); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 486 | } |
| 487 | } else if (inode->i_state & I_DIRTY) { |
| 488 | /* |
| 489 | * Someone redirtied the inode while were writing back |
| 490 | * the pages. |
| 491 | */ |
Andrew Morton | 6610a0b | 2007-10-16 23:30:32 -0700 | [diff] [blame] | 492 | redirty_tail(inode); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 493 | } else if (atomic_read(&inode->i_count)) { |
| 494 | /* |
| 495 | * The inode is clean, inuse |
| 496 | */ |
| 497 | list_move(&inode->i_list, &inode_in_use); |
| 498 | } else { |
| 499 | /* |
| 500 | * The inode is clean, unused |
| 501 | */ |
| 502 | list_move(&inode->i_list, &inode_unused); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 503 | } |
| 504 | } |
Joern Engel | 1c0eeaf | 2007-10-16 23:30:44 -0700 | [diff] [blame] | 505 | inode_sync_complete(inode); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 506 | return ret; |
| 507 | } |
| 508 | |
Jens Axboe | 03ba378 | 2009-09-09 09:08:54 +0200 | [diff] [blame] | 509 | /* |
| 510 | * For WB_SYNC_NONE writeback, the caller does not have the sb pinned |
| 511 | * before calling writeback. So make sure that we do pin it, so it doesn't |
| 512 | * go away while we are writing inodes from it. |
| 513 | * |
| 514 | * Returns 0 if the super was successfully pinned (or pinning wasn't needed), |
| 515 | * 1 if we failed. |
| 516 | */ |
| 517 | static int pin_sb_for_writeback(struct writeback_control *wbc, |
| 518 | struct inode *inode) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 519 | { |
Jens Axboe | 03ba378 | 2009-09-09 09:08:54 +0200 | [diff] [blame] | 520 | struct super_block *sb = inode->i_sb; |
| 521 | |
| 522 | /* |
| 523 | * Caller must already hold the ref for this |
| 524 | */ |
| 525 | if (wbc->sync_mode == WB_SYNC_ALL) { |
| 526 | WARN_ON(!rwsem_is_locked(&sb->s_umount)); |
| 527 | return 0; |
| 528 | } |
| 529 | |
| 530 | spin_lock(&sb_lock); |
| 531 | sb->s_count++; |
| 532 | if (down_read_trylock(&sb->s_umount)) { |
| 533 | if (sb->s_root) { |
| 534 | spin_unlock(&sb_lock); |
| 535 | return 0; |
| 536 | } |
| 537 | /* |
| 538 | * umounted, drop rwsem again and fall through to failure |
| 539 | */ |
| 540 | up_read(&sb->s_umount); |
| 541 | } |
| 542 | |
| 543 | sb->s_count--; |
| 544 | spin_unlock(&sb_lock); |
| 545 | return 1; |
| 546 | } |
| 547 | |
| 548 | static void unpin_sb_for_writeback(struct writeback_control *wbc, |
| 549 | struct inode *inode) |
| 550 | { |
| 551 | struct super_block *sb = inode->i_sb; |
| 552 | |
| 553 | if (wbc->sync_mode == WB_SYNC_ALL) |
| 554 | return; |
| 555 | |
| 556 | up_read(&sb->s_umount); |
| 557 | put_super(sb); |
| 558 | } |
| 559 | |
| 560 | static void writeback_inodes_wb(struct bdi_writeback *wb, |
| 561 | struct writeback_control *wbc) |
| 562 | { |
| 563 | struct super_block *sb = wbc->sb; |
Jens Axboe | 66f3b8e | 2009-09-02 09:19:46 +0200 | [diff] [blame] | 564 | const int is_blkdev_sb = sb_is_blkdev_sb(sb); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 565 | const unsigned long start = jiffies; /* livelock avoidance */ |
| 566 | |
Hans Reiser | ae8547b | 2008-05-07 15:48:57 +0300 | [diff] [blame] | 567 | spin_lock(&inode_lock); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 568 | |
Jens Axboe | 03ba378 | 2009-09-09 09:08:54 +0200 | [diff] [blame] | 569 | if (!wbc->for_kupdate || list_empty(&wb->b_io)) |
| 570 | queue_io(wb, wbc->older_than_this); |
Jens Axboe | 66f3b8e | 2009-09-02 09:19:46 +0200 | [diff] [blame] | 571 | |
Jens Axboe | 03ba378 | 2009-09-09 09:08:54 +0200 | [diff] [blame] | 572 | while (!list_empty(&wb->b_io)) { |
| 573 | struct inode *inode = list_entry(wb->b_io.prev, |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 574 | struct inode, i_list); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 575 | long pages_skipped; |
| 576 | |
Jens Axboe | 66f3b8e | 2009-09-02 09:19:46 +0200 | [diff] [blame] | 577 | /* |
| 578 | * super block given and doesn't match, skip this inode |
| 579 | */ |
| 580 | if (sb && sb != inode->i_sb) { |
| 581 | redirty_tail(inode); |
| 582 | continue; |
| 583 | } |
| 584 | |
Jens Axboe | 03ba378 | 2009-09-09 09:08:54 +0200 | [diff] [blame] | 585 | if (!bdi_cap_writeback_dirty(wb->bdi)) { |
Andrew Morton | 9852a0e7 | 2007-10-16 23:30:33 -0700 | [diff] [blame] | 586 | redirty_tail(inode); |
Jens Axboe | 66f3b8e | 2009-09-02 09:19:46 +0200 | [diff] [blame] | 587 | if (is_blkdev_sb) { |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 588 | /* |
| 589 | * Dirty memory-backed blockdev: the ramdisk |
| 590 | * driver does this. Skip just this inode |
| 591 | */ |
| 592 | continue; |
| 593 | } |
| 594 | /* |
| 595 | * Dirty memory-backed inode against a filesystem other |
| 596 | * than the kernel-internal bdev filesystem. Skip the |
| 597 | * entire superblock. |
| 598 | */ |
| 599 | break; |
| 600 | } |
| 601 | |
Wu Fengguang | 84a8924 | 2009-06-16 15:33:17 -0700 | [diff] [blame] | 602 | if (inode->i_state & (I_NEW | I_WILL_FREE)) { |
Nick Piggin | 7ef0d73 | 2009-03-12 14:31:38 -0700 | [diff] [blame] | 603 | requeue_io(inode); |
| 604 | continue; |
| 605 | } |
| 606 | |
Jens Axboe | 03ba378 | 2009-09-09 09:08:54 +0200 | [diff] [blame] | 607 | if (wbc->nonblocking && bdi_write_congested(wb->bdi)) { |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 608 | wbc->encountered_congestion = 1; |
Jens Axboe | 66f3b8e | 2009-09-02 09:19:46 +0200 | [diff] [blame] | 609 | if (!is_blkdev_sb) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 610 | break; /* Skip a congested fs */ |
Ken Chen | 0e0f4fc | 2007-10-16 23:30:38 -0700 | [diff] [blame] | 611 | requeue_io(inode); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 612 | continue; /* Skip a congested blockdev */ |
| 613 | } |
| 614 | |
Jeff Layton | d2caa3c5 | 2009-04-02 16:56:37 -0700 | [diff] [blame] | 615 | /* |
| 616 | * Was this inode dirtied after sync_sb_inodes was called? |
| 617 | * This keeps sync from extra jobs and livelock. |
| 618 | */ |
| 619 | if (inode_dirtied_after(inode, start)) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 620 | break; |
| 621 | |
Jens Axboe | 03ba378 | 2009-09-09 09:08:54 +0200 | [diff] [blame] | 622 | if (pin_sb_for_writeback(wbc, inode)) { |
| 623 | requeue_io(inode); |
| 624 | continue; |
| 625 | } |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 626 | |
Wu Fengguang | 84a8924 | 2009-06-16 15:33:17 -0700 | [diff] [blame] | 627 | BUG_ON(inode->i_state & (I_FREEING | I_CLEAR)); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 628 | __iget(inode); |
| 629 | pages_skipped = wbc->pages_skipped; |
Christoph Hellwig | 01c0319 | 2009-06-08 13:35:40 +0200 | [diff] [blame] | 630 | writeback_single_inode(inode, wbc); |
Jens Axboe | 03ba378 | 2009-09-09 09:08:54 +0200 | [diff] [blame] | 631 | unpin_sb_for_writeback(wbc, inode); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 632 | if (wbc->pages_skipped != pages_skipped) { |
| 633 | /* |
| 634 | * writeback is not making progress due to locked |
| 635 | * buffers. Skip this inode for now. |
| 636 | */ |
Andrew Morton | f57b9b7 | 2007-10-16 23:30:34 -0700 | [diff] [blame] | 637 | redirty_tail(inode); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 638 | } |
| 639 | spin_unlock(&inode_lock); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 640 | iput(inode); |
OGAWA Hirofumi | 4ffc844 | 2006-03-25 03:07:44 -0800 | [diff] [blame] | 641 | cond_resched(); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 642 | spin_lock(&inode_lock); |
Fengguang Wu | 8bc3be2 | 2008-02-04 22:29:36 -0800 | [diff] [blame] | 643 | if (wbc->nr_to_write <= 0) { |
| 644 | wbc->more_io = 1; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 645 | break; |
Fengguang Wu | 8bc3be2 | 2008-02-04 22:29:36 -0800 | [diff] [blame] | 646 | } |
Jens Axboe | 03ba378 | 2009-09-09 09:08:54 +0200 | [diff] [blame] | 647 | if (!list_empty(&wb->b_more_io)) |
Fengguang Wu | 8bc3be2 | 2008-02-04 22:29:36 -0800 | [diff] [blame] | 648 | wbc->more_io = 1; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 649 | } |
Nick Piggin | 38f2197 | 2009-01-06 14:40:25 -0800 | [diff] [blame] | 650 | |
Jens Axboe | 66f3b8e | 2009-09-02 09:19:46 +0200 | [diff] [blame] | 651 | spin_unlock(&inode_lock); |
| 652 | /* Leave any unwritten inodes on b_io */ |
| 653 | } |
| 654 | |
Jens Axboe | 03ba378 | 2009-09-09 09:08:54 +0200 | [diff] [blame] | 655 | void writeback_inodes_wbc(struct writeback_control *wbc) |
| 656 | { |
| 657 | struct backing_dev_info *bdi = wbc->bdi; |
| 658 | |
| 659 | writeback_inodes_wb(&bdi->wb, wbc); |
| 660 | } |
| 661 | |
| 662 | /* |
| 663 | * The maximum number of pages to writeout in a single bdi flush/kupdate |
| 664 | * operation. We do this so we don't hold I_SYNC against an inode for |
| 665 | * enormous amounts of time, which would block a userspace task which has |
| 666 | * been forced to throttle against that inode. Also, the code reevaluates |
| 667 | * the dirty each time it has written this many pages. |
| 668 | */ |
| 669 | #define MAX_WRITEBACK_PAGES 1024 |
| 670 | |
| 671 | static inline bool over_bground_thresh(void) |
| 672 | { |
| 673 | unsigned long background_thresh, dirty_thresh; |
| 674 | |
| 675 | get_dirty_limits(&background_thresh, &dirty_thresh, NULL, NULL); |
| 676 | |
| 677 | return (global_page_state(NR_FILE_DIRTY) + |
| 678 | global_page_state(NR_UNSTABLE_NFS) >= background_thresh); |
| 679 | } |
| 680 | |
| 681 | /* |
| 682 | * Explicit flushing or periodic writeback of "old" data. |
| 683 | * |
| 684 | * Define "old": the first time one of an inode's pages is dirtied, we mark the |
| 685 | * dirtying-time in the inode's address_space. So this periodic writeback code |
| 686 | * just walks the superblock inode list, writing back any inodes which are |
| 687 | * older than a specific point in time. |
| 688 | * |
| 689 | * Try to run once per dirty_writeback_interval. But if a writeback event |
| 690 | * takes longer than a dirty_writeback_interval interval, then leave a |
| 691 | * one-second gap. |
| 692 | * |
| 693 | * older_than_this takes precedence over nr_to_write. So we'll only write back |
| 694 | * all dirty pages if they are all attached to "old" mappings. |
| 695 | */ |
Jens Axboe | c4a77a6 | 2009-09-16 15:18:25 +0200 | [diff] [blame] | 696 | static long wb_writeback(struct bdi_writeback *wb, |
| 697 | struct wb_writeback_args *args) |
Jens Axboe | 03ba378 | 2009-09-09 09:08:54 +0200 | [diff] [blame] | 698 | { |
| 699 | struct writeback_control wbc = { |
| 700 | .bdi = wb->bdi, |
Jens Axboe | c4a77a6 | 2009-09-16 15:18:25 +0200 | [diff] [blame] | 701 | .sb = args->sb, |
| 702 | .sync_mode = args->sync_mode, |
Jens Axboe | 03ba378 | 2009-09-09 09:08:54 +0200 | [diff] [blame] | 703 | .older_than_this = NULL, |
Jens Axboe | c4a77a6 | 2009-09-16 15:18:25 +0200 | [diff] [blame] | 704 | .for_kupdate = args->for_kupdate, |
| 705 | .range_cyclic = args->range_cyclic, |
Jens Axboe | 03ba378 | 2009-09-09 09:08:54 +0200 | [diff] [blame] | 706 | }; |
| 707 | unsigned long oldest_jif; |
| 708 | long wrote = 0; |
| 709 | |
| 710 | if (wbc.for_kupdate) { |
| 711 | wbc.older_than_this = &oldest_jif; |
| 712 | oldest_jif = jiffies - |
| 713 | msecs_to_jiffies(dirty_expire_interval * 10); |
| 714 | } |
Jens Axboe | c4a77a6 | 2009-09-16 15:18:25 +0200 | [diff] [blame] | 715 | if (!wbc.range_cyclic) { |
| 716 | wbc.range_start = 0; |
| 717 | wbc.range_end = LLONG_MAX; |
| 718 | } |
Jens Axboe | 03ba378 | 2009-09-09 09:08:54 +0200 | [diff] [blame] | 719 | |
| 720 | for (;;) { |
| 721 | /* |
| 722 | * Don't flush anything for non-integrity writeback where |
| 723 | * no nr_pages was given |
| 724 | */ |
Jens Axboe | c4a77a6 | 2009-09-16 15:18:25 +0200 | [diff] [blame] | 725 | if (!args->for_kupdate && args->nr_pages <= 0 && |
| 726 | args->sync_mode == WB_SYNC_NONE) |
Jens Axboe | 03ba378 | 2009-09-09 09:08:54 +0200 | [diff] [blame] | 727 | break; |
| 728 | |
| 729 | /* |
| 730 | * If no specific pages were given and this is just a |
| 731 | * periodic background writeout and we are below the |
| 732 | * background dirty threshold, don't do anything |
| 733 | */ |
Jens Axboe | c4a77a6 | 2009-09-16 15:18:25 +0200 | [diff] [blame] | 734 | if (args->for_kupdate && args->nr_pages <= 0 && |
| 735 | !over_bground_thresh()) |
Jens Axboe | 03ba378 | 2009-09-09 09:08:54 +0200 | [diff] [blame] | 736 | break; |
| 737 | |
| 738 | wbc.more_io = 0; |
| 739 | wbc.encountered_congestion = 0; |
| 740 | wbc.nr_to_write = MAX_WRITEBACK_PAGES; |
| 741 | wbc.pages_skipped = 0; |
| 742 | writeback_inodes_wb(wb, &wbc); |
Jens Axboe | c4a77a6 | 2009-09-16 15:18:25 +0200 | [diff] [blame] | 743 | args->nr_pages -= MAX_WRITEBACK_PAGES - wbc.nr_to_write; |
Jens Axboe | 03ba378 | 2009-09-09 09:08:54 +0200 | [diff] [blame] | 744 | wrote += MAX_WRITEBACK_PAGES - wbc.nr_to_write; |
| 745 | |
| 746 | /* |
| 747 | * If we ran out of stuff to write, bail unless more_io got set |
| 748 | */ |
| 749 | if (wbc.nr_to_write > 0 || wbc.pages_skipped > 0) { |
| 750 | if (wbc.more_io && !wbc.for_kupdate) |
| 751 | continue; |
| 752 | break; |
| 753 | } |
| 754 | } |
| 755 | |
| 756 | return wrote; |
| 757 | } |
| 758 | |
| 759 | /* |
| 760 | * 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^] | 761 | * wb thread yet. ->seen is initially set for each thread that exists |
| 762 | * for this device, when a thread first notices a piece of work it |
| 763 | * clears its bit. Depending on writeback type, the thread will notify |
| 764 | * completion on either receiving the work (WB_SYNC_NONE) or after |
| 765 | * it is done (WB_SYNC_ALL). |
Jens Axboe | 03ba378 | 2009-09-09 09:08:54 +0200 | [diff] [blame] | 766 | */ |
| 767 | static struct bdi_work *get_next_work_item(struct backing_dev_info *bdi, |
| 768 | struct bdi_writeback *wb) |
| 769 | { |
| 770 | struct bdi_work *work, *ret = NULL; |
| 771 | |
| 772 | rcu_read_lock(); |
| 773 | |
| 774 | list_for_each_entry_rcu(work, &bdi->work_list, list) { |
| 775 | if (!test_and_clear_bit(wb->nr, &work->seen)) |
| 776 | continue; |
| 777 | |
| 778 | ret = work; |
| 779 | break; |
| 780 | } |
| 781 | |
| 782 | rcu_read_unlock(); |
| 783 | return ret; |
| 784 | } |
| 785 | |
| 786 | static long wb_check_old_data_flush(struct bdi_writeback *wb) |
| 787 | { |
| 788 | unsigned long expired; |
| 789 | long nr_pages; |
| 790 | |
| 791 | expired = wb->last_old_flush + |
| 792 | msecs_to_jiffies(dirty_writeback_interval * 10); |
| 793 | if (time_before(jiffies, expired)) |
| 794 | return 0; |
| 795 | |
| 796 | wb->last_old_flush = jiffies; |
| 797 | nr_pages = global_page_state(NR_FILE_DIRTY) + |
| 798 | global_page_state(NR_UNSTABLE_NFS) + |
| 799 | (inodes_stat.nr_inodes - inodes_stat.nr_unused); |
| 800 | |
Jens Axboe | c4a77a6 | 2009-09-16 15:18:25 +0200 | [diff] [blame] | 801 | if (nr_pages) { |
| 802 | struct wb_writeback_args args = { |
| 803 | .nr_pages = nr_pages, |
| 804 | .sync_mode = WB_SYNC_NONE, |
| 805 | .for_kupdate = 1, |
| 806 | .range_cyclic = 1, |
| 807 | }; |
| 808 | |
| 809 | return wb_writeback(wb, &args); |
| 810 | } |
Jens Axboe | 03ba378 | 2009-09-09 09:08:54 +0200 | [diff] [blame] | 811 | |
| 812 | return 0; |
| 813 | } |
| 814 | |
| 815 | /* |
| 816 | * Retrieve work items and do the writeback they describe |
| 817 | */ |
| 818 | long wb_do_writeback(struct bdi_writeback *wb, int force_wait) |
| 819 | { |
| 820 | struct backing_dev_info *bdi = wb->bdi; |
| 821 | struct bdi_work *work; |
Jens Axboe | c4a77a6 | 2009-09-16 15:18:25 +0200 | [diff] [blame] | 822 | long wrote = 0; |
Jens Axboe | 03ba378 | 2009-09-09 09:08:54 +0200 | [diff] [blame] | 823 | |
| 824 | while ((work = get_next_work_item(bdi, wb)) != NULL) { |
Jens Axboe | c4a77a6 | 2009-09-16 15:18:25 +0200 | [diff] [blame] | 825 | struct wb_writeback_args args = work->args; |
Jens Axboe | 03ba378 | 2009-09-09 09:08:54 +0200 | [diff] [blame] | 826 | |
| 827 | /* |
| 828 | * Override sync mode, in case we must wait for completion |
| 829 | */ |
| 830 | if (force_wait) |
Jens Axboe | c4a77a6 | 2009-09-16 15:18:25 +0200 | [diff] [blame] | 831 | work->args.sync_mode = args.sync_mode = WB_SYNC_ALL; |
Jens Axboe | 03ba378 | 2009-09-09 09:08:54 +0200 | [diff] [blame] | 832 | |
| 833 | /* |
| 834 | * If this isn't a data integrity operation, just notify |
| 835 | * that we have seen this work and we are now starting it. |
| 836 | */ |
Jens Axboe | c4a77a6 | 2009-09-16 15:18:25 +0200 | [diff] [blame] | 837 | if (args.sync_mode == WB_SYNC_NONE) |
Jens Axboe | 03ba378 | 2009-09-09 09:08:54 +0200 | [diff] [blame] | 838 | wb_clear_pending(wb, work); |
| 839 | |
Jens Axboe | c4a77a6 | 2009-09-16 15:18:25 +0200 | [diff] [blame] | 840 | wrote += wb_writeback(wb, &args); |
Jens Axboe | 03ba378 | 2009-09-09 09:08:54 +0200 | [diff] [blame] | 841 | |
| 842 | /* |
| 843 | * This is a data integrity writeback, so only do the |
| 844 | * notification when we have completed the work. |
| 845 | */ |
Jens Axboe | c4a77a6 | 2009-09-16 15:18:25 +0200 | [diff] [blame] | 846 | if (args.sync_mode == WB_SYNC_ALL) |
Jens Axboe | 03ba378 | 2009-09-09 09:08:54 +0200 | [diff] [blame] | 847 | wb_clear_pending(wb, work); |
| 848 | } |
| 849 | |
| 850 | /* |
| 851 | * Check for periodic writeback, kupdated() style |
| 852 | */ |
| 853 | wrote += wb_check_old_data_flush(wb); |
| 854 | |
| 855 | return wrote; |
| 856 | } |
| 857 | |
| 858 | /* |
| 859 | * Handle writeback of dirty data for the device backed by this bdi. Also |
| 860 | * wakes up periodically and does kupdated style flushing. |
| 861 | */ |
| 862 | int bdi_writeback_task(struct bdi_writeback *wb) |
| 863 | { |
| 864 | unsigned long last_active = jiffies; |
| 865 | unsigned long wait_jiffies = -1UL; |
| 866 | long pages_written; |
| 867 | |
| 868 | while (!kthread_should_stop()) { |
| 869 | pages_written = wb_do_writeback(wb, 0); |
| 870 | |
| 871 | if (pages_written) |
| 872 | last_active = jiffies; |
| 873 | else if (wait_jiffies != -1UL) { |
| 874 | unsigned long max_idle; |
| 875 | |
| 876 | /* |
| 877 | * Longest period of inactivity that we tolerate. If we |
| 878 | * see dirty data again later, the task will get |
| 879 | * recreated automatically. |
| 880 | */ |
| 881 | max_idle = max(5UL * 60 * HZ, wait_jiffies); |
| 882 | if (time_after(jiffies, max_idle + last_active)) |
| 883 | break; |
| 884 | } |
| 885 | |
| 886 | wait_jiffies = msecs_to_jiffies(dirty_writeback_interval * 10); |
| 887 | set_current_state(TASK_INTERRUPTIBLE); |
| 888 | schedule_timeout(wait_jiffies); |
| 889 | try_to_freeze(); |
| 890 | } |
| 891 | |
| 892 | return 0; |
| 893 | } |
| 894 | |
| 895 | /* |
Jens Axboe | b6e5131 | 2009-09-16 15:13:54 +0200 | [diff] [blame] | 896 | * Schedule writeback for all backing devices. This does WB_SYNC_NONE |
| 897 | * writeback, for integrity writeback see bdi_sync_writeback(). |
Jens Axboe | 03ba378 | 2009-09-09 09:08:54 +0200 | [diff] [blame] | 898 | */ |
Jens Axboe | b6e5131 | 2009-09-16 15:13:54 +0200 | [diff] [blame] | 899 | static void bdi_writeback_all(struct super_block *sb, long nr_pages) |
Jens Axboe | 03ba378 | 2009-09-09 09:08:54 +0200 | [diff] [blame] | 900 | { |
Jens Axboe | b6e5131 | 2009-09-16 15:13:54 +0200 | [diff] [blame] | 901 | struct wb_writeback_args args = { |
| 902 | .sb = sb, |
| 903 | .nr_pages = nr_pages, |
| 904 | .sync_mode = WB_SYNC_NONE, |
| 905 | }; |
Jens Axboe | 03ba378 | 2009-09-09 09:08:54 +0200 | [diff] [blame] | 906 | struct backing_dev_info *bdi; |
Jens Axboe | 03ba378 | 2009-09-09 09:08:54 +0200 | [diff] [blame] | 907 | |
Jens Axboe | cfc4ba5 | 2009-09-14 13:12:40 +0200 | [diff] [blame] | 908 | rcu_read_lock(); |
Jens Axboe | 03ba378 | 2009-09-09 09:08:54 +0200 | [diff] [blame] | 909 | |
Jens Axboe | cfc4ba5 | 2009-09-14 13:12:40 +0200 | [diff] [blame] | 910 | list_for_each_entry_rcu(bdi, &bdi_list, bdi_list) { |
Jens Axboe | 03ba378 | 2009-09-09 09:08:54 +0200 | [diff] [blame] | 911 | if (!bdi_has_dirty_io(bdi)) |
| 912 | continue; |
| 913 | |
Jens Axboe | b6e5131 | 2009-09-16 15:13:54 +0200 | [diff] [blame] | 914 | bdi_alloc_queue_work(bdi, &args); |
Jens Axboe | 03ba378 | 2009-09-09 09:08:54 +0200 | [diff] [blame] | 915 | } |
| 916 | |
Jens Axboe | cfc4ba5 | 2009-09-14 13:12:40 +0200 | [diff] [blame] | 917 | rcu_read_unlock(); |
Jens Axboe | 03ba378 | 2009-09-09 09:08:54 +0200 | [diff] [blame] | 918 | } |
| 919 | |
| 920 | /* |
| 921 | * Start writeback of `nr_pages' pages. If `nr_pages' is zero, write back |
| 922 | * the whole world. |
| 923 | */ |
| 924 | void wakeup_flusher_threads(long nr_pages) |
| 925 | { |
Jens Axboe | 03ba378 | 2009-09-09 09:08:54 +0200 | [diff] [blame] | 926 | if (nr_pages == 0) |
| 927 | nr_pages = global_page_state(NR_FILE_DIRTY) + |
| 928 | global_page_state(NR_UNSTABLE_NFS); |
Jens Axboe | b6e5131 | 2009-09-16 15:13:54 +0200 | [diff] [blame] | 929 | bdi_writeback_all(NULL, nr_pages); |
Jens Axboe | 03ba378 | 2009-09-09 09:08:54 +0200 | [diff] [blame] | 930 | } |
| 931 | |
| 932 | static noinline void block_dump___mark_inode_dirty(struct inode *inode) |
| 933 | { |
| 934 | if (inode->i_ino || strcmp(inode->i_sb->s_id, "bdev")) { |
| 935 | struct dentry *dentry; |
| 936 | const char *name = "?"; |
| 937 | |
| 938 | dentry = d_find_alias(inode); |
| 939 | if (dentry) { |
| 940 | spin_lock(&dentry->d_lock); |
| 941 | name = (const char *) dentry->d_name.name; |
| 942 | } |
| 943 | printk(KERN_DEBUG |
| 944 | "%s(%d): dirtied inode %lu (%s) on %s\n", |
| 945 | current->comm, task_pid_nr(current), inode->i_ino, |
| 946 | name, inode->i_sb->s_id); |
| 947 | if (dentry) { |
| 948 | spin_unlock(&dentry->d_lock); |
| 949 | dput(dentry); |
| 950 | } |
| 951 | } |
| 952 | } |
| 953 | |
| 954 | /** |
| 955 | * __mark_inode_dirty - internal function |
| 956 | * @inode: inode to mark |
| 957 | * @flags: what kind of dirty (i.e. I_DIRTY_SYNC) |
| 958 | * Mark an inode as dirty. Callers should use mark_inode_dirty or |
| 959 | * mark_inode_dirty_sync. |
| 960 | * |
| 961 | * Put the inode on the super block's dirty list. |
| 962 | * |
| 963 | * CAREFUL! We mark it dirty unconditionally, but move it onto the |
| 964 | * dirty list only if it is hashed or if it refers to a blockdev. |
| 965 | * If it was not hashed, it will never be added to the dirty list |
| 966 | * even if it is later hashed, as it will have been marked dirty already. |
| 967 | * |
| 968 | * In short, make sure you hash any inodes _before_ you start marking |
| 969 | * them dirty. |
| 970 | * |
| 971 | * This function *must* be atomic for the I_DIRTY_PAGES case - |
| 972 | * set_page_dirty() is called under spinlock in several places. |
| 973 | * |
| 974 | * Note that for blockdevs, inode->dirtied_when represents the dirtying time of |
| 975 | * the block-special inode (/dev/hda1) itself. And the ->dirtied_when field of |
| 976 | * the kernel-internal blockdev inode represents the dirtying time of the |
| 977 | * blockdev's pages. This is why for I_DIRTY_PAGES we always use |
| 978 | * page->mapping->host, so the page-dirtying time is recorded in the internal |
| 979 | * blockdev inode. |
| 980 | */ |
| 981 | void __mark_inode_dirty(struct inode *inode, int flags) |
| 982 | { |
| 983 | struct super_block *sb = inode->i_sb; |
| 984 | |
| 985 | /* |
| 986 | * Don't do this for I_DIRTY_PAGES - that doesn't actually |
| 987 | * dirty the inode itself |
| 988 | */ |
| 989 | if (flags & (I_DIRTY_SYNC | I_DIRTY_DATASYNC)) { |
| 990 | if (sb->s_op->dirty_inode) |
| 991 | sb->s_op->dirty_inode(inode); |
| 992 | } |
| 993 | |
| 994 | /* |
| 995 | * make sure that changes are seen by all cpus before we test i_state |
| 996 | * -- mikulas |
| 997 | */ |
| 998 | smp_mb(); |
| 999 | |
| 1000 | /* avoid the locking if we can */ |
| 1001 | if ((inode->i_state & flags) == flags) |
| 1002 | return; |
| 1003 | |
| 1004 | if (unlikely(block_dump)) |
| 1005 | block_dump___mark_inode_dirty(inode); |
| 1006 | |
| 1007 | spin_lock(&inode_lock); |
| 1008 | if ((inode->i_state & flags) != flags) { |
| 1009 | const int was_dirty = inode->i_state & I_DIRTY; |
| 1010 | |
| 1011 | inode->i_state |= flags; |
| 1012 | |
| 1013 | /* |
| 1014 | * If the inode is being synced, just update its dirty state. |
| 1015 | * The unlocker will place the inode on the appropriate |
| 1016 | * superblock list, based upon its state. |
| 1017 | */ |
| 1018 | if (inode->i_state & I_SYNC) |
| 1019 | goto out; |
| 1020 | |
| 1021 | /* |
| 1022 | * Only add valid (hashed) inodes to the superblock's |
| 1023 | * dirty list. Add blockdev inodes as well. |
| 1024 | */ |
| 1025 | if (!S_ISBLK(inode->i_mode)) { |
| 1026 | if (hlist_unhashed(&inode->i_hash)) |
| 1027 | goto out; |
| 1028 | } |
| 1029 | if (inode->i_state & (I_FREEING|I_CLEAR)) |
| 1030 | goto out; |
| 1031 | |
| 1032 | /* |
| 1033 | * If the inode was already on b_dirty/b_io/b_more_io, don't |
| 1034 | * reposition it (that would break b_dirty time-ordering). |
| 1035 | */ |
| 1036 | if (!was_dirty) { |
| 1037 | struct bdi_writeback *wb = &inode_to_bdi(inode)->wb; |
Jens Axboe | 500b067 | 2009-09-09 09:10:25 +0200 | [diff] [blame] | 1038 | struct backing_dev_info *bdi = wb->bdi; |
| 1039 | |
| 1040 | if (bdi_cap_writeback_dirty(bdi) && |
| 1041 | !test_bit(BDI_registered, &bdi->state)) { |
| 1042 | WARN_ON(1); |
| 1043 | printk(KERN_ERR "bdi-%s not registered\n", |
| 1044 | bdi->name); |
| 1045 | } |
Jens Axboe | 03ba378 | 2009-09-09 09:08:54 +0200 | [diff] [blame] | 1046 | |
| 1047 | inode->dirtied_when = jiffies; |
| 1048 | list_move(&inode->i_list, &wb->b_dirty); |
| 1049 | } |
| 1050 | } |
| 1051 | out: |
| 1052 | spin_unlock(&inode_lock); |
| 1053 | } |
| 1054 | EXPORT_SYMBOL(__mark_inode_dirty); |
| 1055 | |
Jens Axboe | 66f3b8e | 2009-09-02 09:19:46 +0200 | [diff] [blame] | 1056 | /* |
| 1057 | * Write out a superblock's list of dirty inodes. A wait will be performed |
| 1058 | * upon no inodes, all inodes or the final one, depending upon sync_mode. |
| 1059 | * |
| 1060 | * If older_than_this is non-NULL, then only write out inodes which |
| 1061 | * had their first dirtying at a time earlier than *older_than_this. |
| 1062 | * |
| 1063 | * If we're a pdlfush thread, then implement pdflush collision avoidance |
| 1064 | * against the entire list. |
| 1065 | * |
| 1066 | * If `bdi' is non-zero then we're being asked to writeback a specific queue. |
| 1067 | * This function assumes that the blockdev superblock's inodes are backed by |
| 1068 | * a variety of queues, so all inodes are searched. For other superblocks, |
| 1069 | * assume that all inodes are backed by the same queue. |
| 1070 | * |
Jens Axboe | 66f3b8e | 2009-09-02 09:19:46 +0200 | [diff] [blame] | 1071 | * The inodes to be written are parked on bdi->b_io. They are moved back onto |
| 1072 | * bdi->b_dirty as they are selected for writing. This way, none can be missed |
| 1073 | * on the writer throttling path, and we get decent balancing between many |
| 1074 | * throttled threads: we don't want them all piling up on inode_sync_wait. |
| 1075 | */ |
Jens Axboe | b6e5131 | 2009-09-16 15:13:54 +0200 | [diff] [blame] | 1076 | static void wait_sb_inodes(struct super_block *sb) |
Jens Axboe | 66f3b8e | 2009-09-02 09:19:46 +0200 | [diff] [blame] | 1077 | { |
Jens Axboe | 03ba378 | 2009-09-09 09:08:54 +0200 | [diff] [blame] | 1078 | struct inode *inode, *old_inode = NULL; |
Jens Axboe | 66f3b8e | 2009-09-02 09:19:46 +0200 | [diff] [blame] | 1079 | |
Jens Axboe | 03ba378 | 2009-09-09 09:08:54 +0200 | [diff] [blame] | 1080 | /* |
| 1081 | * We need to be protected against the filesystem going from |
| 1082 | * r/o to r/w or vice versa. |
| 1083 | */ |
Jens Axboe | b6e5131 | 2009-09-16 15:13:54 +0200 | [diff] [blame] | 1084 | WARN_ON(!rwsem_is_locked(&sb->s_umount)); |
Jens Axboe | 66f3b8e | 2009-09-02 09:19:46 +0200 | [diff] [blame] | 1085 | |
Jens Axboe | 03ba378 | 2009-09-09 09:08:54 +0200 | [diff] [blame] | 1086 | spin_lock(&inode_lock); |
| 1087 | |
| 1088 | /* |
| 1089 | * Data integrity sync. Must wait for all pages under writeback, |
| 1090 | * because there may have been pages dirtied before our sync |
| 1091 | * call, but which had writeout started before we write it out. |
| 1092 | * In which case, the inode may not be on the dirty list, but |
| 1093 | * we still have to wait for that writeout. |
| 1094 | */ |
Jens Axboe | b6e5131 | 2009-09-16 15:13:54 +0200 | [diff] [blame] | 1095 | list_for_each_entry(inode, &sb->s_inodes, i_sb_list) { |
Jens Axboe | 03ba378 | 2009-09-09 09:08:54 +0200 | [diff] [blame] | 1096 | struct address_space *mapping; |
| 1097 | |
| 1098 | if (inode->i_state & (I_FREEING|I_CLEAR|I_WILL_FREE|I_NEW)) |
| 1099 | continue; |
| 1100 | mapping = inode->i_mapping; |
| 1101 | if (mapping->nrpages == 0) |
| 1102 | continue; |
| 1103 | __iget(inode); |
| 1104 | spin_unlock(&inode_lock); |
| 1105 | /* |
| 1106 | * We hold a reference to 'inode' so it couldn't have |
| 1107 | * been removed from s_inodes list while we dropped the |
| 1108 | * inode_lock. We cannot iput the inode now as we can |
| 1109 | * be holding the last reference and we cannot iput it |
| 1110 | * under inode_lock. So we keep the reference and iput |
| 1111 | * it later. |
| 1112 | */ |
| 1113 | iput(old_inode); |
| 1114 | old_inode = inode; |
| 1115 | |
| 1116 | filemap_fdatawait(mapping); |
| 1117 | |
| 1118 | cond_resched(); |
Nick Piggin | 38f2197 | 2009-01-06 14:40:25 -0800 | [diff] [blame] | 1119 | |
Jens Axboe | 66f3b8e | 2009-09-02 09:19:46 +0200 | [diff] [blame] | 1120 | spin_lock(&inode_lock); |
Jens Axboe | 66f3b8e | 2009-09-02 09:19:46 +0200 | [diff] [blame] | 1121 | } |
Jens Axboe | 03ba378 | 2009-09-09 09:08:54 +0200 | [diff] [blame] | 1122 | spin_unlock(&inode_lock); |
| 1123 | iput(old_inode); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1124 | } |
| 1125 | |
Jens Axboe | d8a8559 | 2009-09-02 12:34:32 +0200 | [diff] [blame] | 1126 | /** |
| 1127 | * writeback_inodes_sb - writeback dirty inodes from given super_block |
| 1128 | * @sb: the superblock |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1129 | * |
Jens Axboe | d8a8559 | 2009-09-02 12:34:32 +0200 | [diff] [blame] | 1130 | * Start writeback on some inodes on this super_block. No guarantees are made |
| 1131 | * on how many (if any) will be written, and this function does not wait |
| 1132 | * for IO completion of submitted IO. The number of pages submitted is |
| 1133 | * returned. |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1134 | */ |
Jens Axboe | b6e5131 | 2009-09-16 15:13:54 +0200 | [diff] [blame] | 1135 | void writeback_inodes_sb(struct super_block *sb) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1136 | { |
Jens Axboe | d8a8559 | 2009-09-02 12:34:32 +0200 | [diff] [blame] | 1137 | unsigned long nr_dirty = global_page_state(NR_FILE_DIRTY); |
| 1138 | unsigned long nr_unstable = global_page_state(NR_UNSTABLE_NFS); |
| 1139 | long nr_to_write; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1140 | |
Jens Axboe | d8a8559 | 2009-09-02 12:34:32 +0200 | [diff] [blame] | 1141 | nr_to_write = nr_dirty + nr_unstable + |
Nick Piggin | 38f2197 | 2009-01-06 14:40:25 -0800 | [diff] [blame] | 1142 | (inodes_stat.nr_inodes - inodes_stat.nr_unused); |
Nick Piggin | 38f2197 | 2009-01-06 14:40:25 -0800 | [diff] [blame] | 1143 | |
Jens Axboe | b6e5131 | 2009-09-16 15:13:54 +0200 | [diff] [blame] | 1144 | bdi_writeback_all(sb, nr_to_write); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1145 | } |
Jens Axboe | d8a8559 | 2009-09-02 12:34:32 +0200 | [diff] [blame] | 1146 | EXPORT_SYMBOL(writeback_inodes_sb); |
| 1147 | |
| 1148 | /** |
| 1149 | * sync_inodes_sb - sync sb inode pages |
| 1150 | * @sb: the superblock |
| 1151 | * |
| 1152 | * This function writes and waits on any dirty inode belonging to this |
| 1153 | * super_block. The number of pages synced is returned. |
| 1154 | */ |
Jens Axboe | b6e5131 | 2009-09-16 15:13:54 +0200 | [diff] [blame] | 1155 | void sync_inodes_sb(struct super_block *sb) |
Jens Axboe | d8a8559 | 2009-09-02 12:34:32 +0200 | [diff] [blame] | 1156 | { |
Jens Axboe | b6e5131 | 2009-09-16 15:13:54 +0200 | [diff] [blame] | 1157 | bdi_sync_writeback(sb->s_bdi, sb); |
| 1158 | wait_sb_inodes(sb); |
Jens Axboe | d8a8559 | 2009-09-02 12:34:32 +0200 | [diff] [blame] | 1159 | } |
| 1160 | EXPORT_SYMBOL(sync_inodes_sb); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1161 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1162 | /** |
Andrea Arcangeli | 7f04c26 | 2005-10-30 15:03:05 -0800 | [diff] [blame] | 1163 | * write_inode_now - write an inode to disk |
| 1164 | * @inode: inode to write to disk |
| 1165 | * @sync: whether the write should be synchronous or not |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1166 | * |
Andrea Arcangeli | 7f04c26 | 2005-10-30 15:03:05 -0800 | [diff] [blame] | 1167 | * This function commits an inode to disk immediately if it is dirty. This is |
| 1168 | * primarily needed by knfsd. |
| 1169 | * |
| 1170 | * 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] | 1171 | */ |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1172 | int write_inode_now(struct inode *inode, int sync) |
| 1173 | { |
| 1174 | int ret; |
| 1175 | struct writeback_control wbc = { |
| 1176 | .nr_to_write = LONG_MAX, |
Mike Galbraith | 18914b1 | 2008-02-08 04:20:23 -0800 | [diff] [blame] | 1177 | .sync_mode = sync ? WB_SYNC_ALL : WB_SYNC_NONE, |
OGAWA Hirofumi | 111ebb6 | 2006-06-23 02:03:26 -0700 | [diff] [blame] | 1178 | .range_start = 0, |
| 1179 | .range_end = LLONG_MAX, |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1180 | }; |
| 1181 | |
| 1182 | if (!mapping_cap_writeback_dirty(inode->i_mapping)) |
Andrew Morton | 49364ce | 2005-11-07 00:59:15 -0800 | [diff] [blame] | 1183 | wbc.nr_to_write = 0; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1184 | |
| 1185 | might_sleep(); |
| 1186 | spin_lock(&inode_lock); |
Christoph Hellwig | 01c0319 | 2009-06-08 13:35:40 +0200 | [diff] [blame] | 1187 | ret = writeback_single_inode(inode, &wbc); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1188 | spin_unlock(&inode_lock); |
| 1189 | if (sync) |
Joern Engel | 1c0eeaf | 2007-10-16 23:30:44 -0700 | [diff] [blame] | 1190 | inode_sync_wait(inode); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1191 | return ret; |
| 1192 | } |
| 1193 | EXPORT_SYMBOL(write_inode_now); |
| 1194 | |
| 1195 | /** |
| 1196 | * sync_inode - write an inode and its pages to disk. |
| 1197 | * @inode: the inode to sync |
| 1198 | * @wbc: controls the writeback mode |
| 1199 | * |
| 1200 | * sync_inode() will write an inode and its pages to disk. It will also |
| 1201 | * correctly update the inode on its superblock's dirty inode lists and will |
| 1202 | * update inode->i_state. |
| 1203 | * |
| 1204 | * The caller must have a ref on the inode. |
| 1205 | */ |
| 1206 | int sync_inode(struct inode *inode, struct writeback_control *wbc) |
| 1207 | { |
| 1208 | int ret; |
| 1209 | |
| 1210 | spin_lock(&inode_lock); |
Christoph Hellwig | 01c0319 | 2009-06-08 13:35:40 +0200 | [diff] [blame] | 1211 | ret = writeback_single_inode(inode, wbc); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1212 | spin_unlock(&inode_lock); |
| 1213 | return ret; |
| 1214 | } |
| 1215 | EXPORT_SYMBOL(sync_inode); |