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> |
Tejun Heo | 5a0e3ad | 2010-03-24 17:04:11 +0900 | [diff] [blame] | 19 | #include <linux/slab.h> |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 20 | #include <linux/sched.h> |
| 21 | #include <linux/fs.h> |
| 22 | #include <linux/mm.h> |
Jens Axboe | 03ba378 | 2009-09-09 09:08:54 +0200 | [diff] [blame] | 23 | #include <linux/kthread.h> |
| 24 | #include <linux/freezer.h> |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 25 | #include <linux/writeback.h> |
| 26 | #include <linux/blkdev.h> |
| 27 | #include <linux/backing-dev.h> |
| 28 | #include <linux/buffer_head.h> |
David Howells | 07f3f05c | 2006-09-30 20:52:18 +0200 | [diff] [blame] | 29 | #include "internal.h" |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 30 | |
Jens Axboe | 66f3b8e | 2009-09-02 09:19:46 +0200 | [diff] [blame] | 31 | #define inode_to_bdi(inode) ((inode)->i_mapping->backing_dev_info) |
Adrian Bunk | f11b00f | 2008-04-29 00:58:56 -0700 | [diff] [blame] | 32 | |
Jens Axboe | 03ba378 | 2009-09-09 09:08:54 +0200 | [diff] [blame] | 33 | /* |
Jens Axboe | d0bceac | 2009-05-18 08:20:32 +0200 | [diff] [blame] | 34 | * We don't actually have pdflush, but this one is exported though /proc... |
| 35 | */ |
| 36 | int nr_pdflush_threads; |
| 37 | |
| 38 | /* |
Jens Axboe | c4a77a6 | 2009-09-16 15:18:25 +0200 | [diff] [blame] | 39 | * Passed into wb_writeback(), essentially a subset of writeback_control |
| 40 | */ |
| 41 | struct wb_writeback_args { |
| 42 | long nr_pages; |
| 43 | struct super_block *sb; |
| 44 | enum writeback_sync_modes sync_mode; |
H Hartley Sweeten | 52957fe | 2010-04-01 20:36:30 -0500 | [diff] [blame] | 45 | unsigned int for_kupdate:1; |
| 46 | unsigned int range_cyclic:1; |
| 47 | unsigned int for_background:1; |
Jens Axboe | c4a77a6 | 2009-09-16 15:18:25 +0200 | [diff] [blame] | 48 | }; |
| 49 | |
| 50 | /* |
Jens Axboe | 03ba378 | 2009-09-09 09:08:54 +0200 | [diff] [blame] | 51 | * Work items for the bdi_writeback threads |
Adrian Bunk | f11b00f | 2008-04-29 00:58:56 -0700 | [diff] [blame] | 52 | */ |
Jens Axboe | 03ba378 | 2009-09-09 09:08:54 +0200 | [diff] [blame] | 53 | struct bdi_work { |
Jens Axboe | 8010c3b | 2009-09-15 20:04:57 +0200 | [diff] [blame] | 54 | struct list_head list; /* pending work list */ |
| 55 | struct rcu_head rcu_head; /* for RCU free/clear of work */ |
Jens Axboe | 03ba378 | 2009-09-09 09:08:54 +0200 | [diff] [blame] | 56 | |
Jens Axboe | 8010c3b | 2009-09-15 20:04:57 +0200 | [diff] [blame] | 57 | unsigned long seen; /* threads that have seen this work */ |
| 58 | atomic_t pending; /* number of threads still to do work */ |
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 | struct wb_writeback_args args; /* writeback arguments */ |
Jens Axboe | 03ba378 | 2009-09-09 09:08:54 +0200 | [diff] [blame] | 61 | |
Jens Axboe | 8010c3b | 2009-09-15 20:04:57 +0200 | [diff] [blame] | 62 | unsigned long state; /* flag bits, see WS_* */ |
Jens Axboe | 03ba378 | 2009-09-09 09:08:54 +0200 | [diff] [blame] | 63 | }; |
| 64 | |
| 65 | enum { |
| 66 | WS_USED_B = 0, |
| 67 | WS_ONSTACK_B, |
| 68 | }; |
| 69 | |
| 70 | #define WS_USED (1 << WS_USED_B) |
| 71 | #define WS_ONSTACK (1 << WS_ONSTACK_B) |
| 72 | |
| 73 | static inline bool bdi_work_on_stack(struct bdi_work *work) |
Adrian Bunk | f11b00f | 2008-04-29 00:58:56 -0700 | [diff] [blame] | 74 | { |
Jens Axboe | 03ba378 | 2009-09-09 09:08:54 +0200 | [diff] [blame] | 75 | return test_bit(WS_ONSTACK_B, &work->state); |
| 76 | } |
| 77 | |
| 78 | static inline void bdi_work_init(struct bdi_work *work, |
Jens Axboe | b6e5131 | 2009-09-16 15:13:54 +0200 | [diff] [blame] | 79 | struct wb_writeback_args *args) |
Jens Axboe | 03ba378 | 2009-09-09 09:08:54 +0200 | [diff] [blame] | 80 | { |
| 81 | INIT_RCU_HEAD(&work->rcu_head); |
Jens Axboe | b6e5131 | 2009-09-16 15:13:54 +0200 | [diff] [blame] | 82 | work->args = *args; |
Jens Axboe | 03ba378 | 2009-09-09 09:08:54 +0200 | [diff] [blame] | 83 | work->state = WS_USED; |
| 84 | } |
| 85 | |
Adrian Bunk | f11b00f | 2008-04-29 00:58:56 -0700 | [diff] [blame] | 86 | /** |
| 87 | * writeback_in_progress - determine whether there is writeback in progress |
| 88 | * @bdi: the device's backing_dev_info structure. |
| 89 | * |
Jens Axboe | 03ba378 | 2009-09-09 09:08:54 +0200 | [diff] [blame] | 90 | * Determine whether there is writeback waiting to be handled against a |
| 91 | * backing device. |
Adrian Bunk | f11b00f | 2008-04-29 00:58:56 -0700 | [diff] [blame] | 92 | */ |
| 93 | int writeback_in_progress(struct backing_dev_info *bdi) |
| 94 | { |
Jens Axboe | 03ba378 | 2009-09-09 09:08:54 +0200 | [diff] [blame] | 95 | return !list_empty(&bdi->work_list); |
Adrian Bunk | f11b00f | 2008-04-29 00:58:56 -0700 | [diff] [blame] | 96 | } |
| 97 | |
Jens Axboe | 03ba378 | 2009-09-09 09:08:54 +0200 | [diff] [blame] | 98 | static void bdi_work_clear(struct bdi_work *work) |
Adrian Bunk | f11b00f | 2008-04-29 00:58:56 -0700 | [diff] [blame] | 99 | { |
Jens Axboe | 03ba378 | 2009-09-09 09:08:54 +0200 | [diff] [blame] | 100 | clear_bit(WS_USED_B, &work->state); |
| 101 | smp_mb__after_clear_bit(); |
Nick Piggin | 1ef7d9a | 2009-09-15 21:37:55 +0200 | [diff] [blame] | 102 | /* |
| 103 | * work can have disappeared at this point. bit waitq functions |
| 104 | * should be able to tolerate this, provided bdi_sched_wait does |
| 105 | * not dereference it's pointer argument. |
| 106 | */ |
Jens Axboe | 03ba378 | 2009-09-09 09:08:54 +0200 | [diff] [blame] | 107 | wake_up_bit(&work->state, WS_USED_B); |
Adrian Bunk | f11b00f | 2008-04-29 00:58:56 -0700 | [diff] [blame] | 108 | } |
| 109 | |
Jens Axboe | 03ba378 | 2009-09-09 09:08:54 +0200 | [diff] [blame] | 110 | static void bdi_work_free(struct rcu_head *head) |
Nick Piggin | 4195f73 | 2009-05-28 09:01:15 +0200 | [diff] [blame] | 111 | { |
Jens Axboe | 03ba378 | 2009-09-09 09:08:54 +0200 | [diff] [blame] | 112 | struct bdi_work *work = container_of(head, struct bdi_work, rcu_head); |
Nick Piggin | 4195f73 | 2009-05-28 09:01:15 +0200 | [diff] [blame] | 113 | |
Jens Axboe | 03ba378 | 2009-09-09 09:08:54 +0200 | [diff] [blame] | 114 | if (!bdi_work_on_stack(work)) |
| 115 | kfree(work); |
| 116 | else |
| 117 | bdi_work_clear(work); |
| 118 | } |
| 119 | |
| 120 | static void wb_work_complete(struct bdi_work *work) |
| 121 | { |
Jens Axboe | c4a77a6 | 2009-09-16 15:18:25 +0200 | [diff] [blame] | 122 | const enum writeback_sync_modes sync_mode = work->args.sync_mode; |
Nick Piggin | 77b9d05 | 2009-09-15 21:34:51 +0200 | [diff] [blame] | 123 | int onstack = bdi_work_on_stack(work); |
Jens Axboe | 03ba378 | 2009-09-09 09:08:54 +0200 | [diff] [blame] | 124 | |
| 125 | /* |
| 126 | * For allocated work, we can clear the done/seen bit right here. |
| 127 | * For on-stack work, we need to postpone both the clear and free |
| 128 | * to after the RCU grace period, since the stack could be invalidated |
| 129 | * as soon as bdi_work_clear() has done the wakeup. |
| 130 | */ |
Nick Piggin | 77b9d05 | 2009-09-15 21:34:51 +0200 | [diff] [blame] | 131 | if (!onstack) |
Jens Axboe | 03ba378 | 2009-09-09 09:08:54 +0200 | [diff] [blame] | 132 | bdi_work_clear(work); |
Nick Piggin | 77b9d05 | 2009-09-15 21:34:51 +0200 | [diff] [blame] | 133 | if (sync_mode == WB_SYNC_NONE || onstack) |
Jens Axboe | 03ba378 | 2009-09-09 09:08:54 +0200 | [diff] [blame] | 134 | call_rcu(&work->rcu_head, bdi_work_free); |
| 135 | } |
| 136 | |
| 137 | static void wb_clear_pending(struct bdi_writeback *wb, struct bdi_work *work) |
| 138 | { |
| 139 | /* |
| 140 | * The caller has retrieved the work arguments from this work, |
| 141 | * drop our reference. If this is the last ref, delete and free it |
| 142 | */ |
| 143 | if (atomic_dec_and_test(&work->pending)) { |
| 144 | struct backing_dev_info *bdi = wb->bdi; |
| 145 | |
| 146 | spin_lock(&bdi->wb_lock); |
| 147 | list_del_rcu(&work->list); |
| 148 | spin_unlock(&bdi->wb_lock); |
| 149 | |
| 150 | wb_work_complete(work); |
Nick Piggin | 4195f73 | 2009-05-28 09:01:15 +0200 | [diff] [blame] | 151 | } |
| 152 | } |
| 153 | |
Jens Axboe | 03ba378 | 2009-09-09 09:08:54 +0200 | [diff] [blame] | 154 | 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] | 155 | { |
Jens Axboe | bcddc3f | 2009-09-13 20:07:36 +0200 | [diff] [blame] | 156 | work->seen = bdi->wb_mask; |
| 157 | BUG_ON(!work->seen); |
| 158 | atomic_set(&work->pending, bdi->wb_cnt); |
| 159 | BUG_ON(!bdi->wb_cnt); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 160 | |
Jens Axboe | bcddc3f | 2009-09-13 20:07:36 +0200 | [diff] [blame] | 161 | /* |
Nick Piggin | deed62e | 2009-09-15 21:32:58 +0200 | [diff] [blame] | 162 | * list_add_tail_rcu() contains the necessary barriers to |
| 163 | * make sure the above stores are seen before the item is |
| 164 | * noticed on the list |
Jens Axboe | bcddc3f | 2009-09-13 20:07:36 +0200 | [diff] [blame] | 165 | */ |
Jens Axboe | bcddc3f | 2009-09-13 20:07:36 +0200 | [diff] [blame] | 166 | spin_lock(&bdi->wb_lock); |
| 167 | list_add_tail_rcu(&work->list, &bdi->work_list); |
| 168 | spin_unlock(&bdi->wb_lock); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 169 | |
| 170 | /* |
Jens Axboe | 03ba378 | 2009-09-09 09:08:54 +0200 | [diff] [blame] | 171 | * If the default thread isn't there, make sure we add it. When |
| 172 | * it gets created and wakes up, we'll run this work. |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 173 | */ |
Jens Axboe | 03ba378 | 2009-09-09 09:08:54 +0200 | [diff] [blame] | 174 | if (unlikely(list_empty_careful(&bdi->wb_list))) |
| 175 | wake_up_process(default_backing_dev_info.wb.task); |
| 176 | else { |
| 177 | struct bdi_writeback *wb = &bdi->wb; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 178 | |
Nick Piggin | 1ef7d9a | 2009-09-15 21:37:55 +0200 | [diff] [blame] | 179 | if (wb->task) |
Jens Axboe | 03ba378 | 2009-09-09 09:08:54 +0200 | [diff] [blame] | 180 | wake_up_process(wb->task); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 181 | } |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 182 | } |
| 183 | |
Jens Axboe | 03ba378 | 2009-09-09 09:08:54 +0200 | [diff] [blame] | 184 | /* |
| 185 | * Used for on-stack allocated work items. The caller needs to wait until |
| 186 | * the wb threads have acked the work before it's safe to continue. |
| 187 | */ |
| 188 | static void bdi_wait_on_work_clear(struct bdi_work *work) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 189 | { |
Jens Axboe | 03ba378 | 2009-09-09 09:08:54 +0200 | [diff] [blame] | 190 | wait_on_bit(&work->state, WS_USED_B, bdi_sched_wait, |
| 191 | TASK_UNINTERRUPTIBLE); |
| 192 | } |
| 193 | |
Jens Axboe | f11fcae | 2009-09-15 09:53:35 +0200 | [diff] [blame] | 194 | static void bdi_alloc_queue_work(struct backing_dev_info *bdi, |
Jens Axboe | f17625b | 2010-06-01 11:05:22 +0200 | [diff] [blame] | 195 | struct wb_writeback_args *args) |
Jens Axboe | 03ba378 | 2009-09-09 09:08:54 +0200 | [diff] [blame] | 196 | { |
| 197 | struct bdi_work *work; |
| 198 | |
Jens Axboe | bcddc3f | 2009-09-13 20:07:36 +0200 | [diff] [blame] | 199 | /* |
| 200 | * This is WB_SYNC_NONE writeback, so if allocation fails just |
| 201 | * wakeup the thread for old dirty data writeback |
| 202 | */ |
Jens Axboe | 03ba378 | 2009-09-09 09:08:54 +0200 | [diff] [blame] | 203 | work = kmalloc(sizeof(*work), GFP_ATOMIC); |
Jens Axboe | bcddc3f | 2009-09-13 20:07:36 +0200 | [diff] [blame] | 204 | if (work) { |
Jens Axboe | b6e5131 | 2009-09-16 15:13:54 +0200 | [diff] [blame] | 205 | bdi_work_init(work, args); |
Jens Axboe | bcddc3f | 2009-09-13 20:07:36 +0200 | [diff] [blame] | 206 | bdi_queue_work(bdi, work); |
| 207 | } else { |
| 208 | struct bdi_writeback *wb = &bdi->wb; |
Jens Axboe | 03ba378 | 2009-09-09 09:08:54 +0200 | [diff] [blame] | 209 | |
Jens Axboe | bcddc3f | 2009-09-13 20:07:36 +0200 | [diff] [blame] | 210 | if (wb->task) |
| 211 | wake_up_process(wb->task); |
| 212 | } |
Jens Axboe | 03ba378 | 2009-09-09 09:08:54 +0200 | [diff] [blame] | 213 | } |
| 214 | |
Jens Axboe | b6e5131 | 2009-09-16 15:13:54 +0200 | [diff] [blame] | 215 | /** |
| 216 | * bdi_sync_writeback - start and wait for writeback |
| 217 | * @bdi: the backing device to write from |
| 218 | * @sb: write inodes from this super_block |
| 219 | * |
| 220 | * Description: |
| 221 | * This does WB_SYNC_ALL data integrity writeback and waits for the |
| 222 | * IO to complete. Callers must hold the sb s_umount semaphore for |
| 223 | * reading, to avoid having the super disappear before we are done. |
| 224 | */ |
| 225 | static void bdi_sync_writeback(struct backing_dev_info *bdi, |
| 226 | struct super_block *sb) |
Jens Axboe | 03ba378 | 2009-09-09 09:08:54 +0200 | [diff] [blame] | 227 | { |
Jens Axboe | b6e5131 | 2009-09-16 15:13:54 +0200 | [diff] [blame] | 228 | struct wb_writeback_args args = { |
| 229 | .sb = sb, |
| 230 | .sync_mode = WB_SYNC_ALL, |
| 231 | .nr_pages = LONG_MAX, |
| 232 | .range_cyclic = 0, |
| 233 | }; |
| 234 | struct bdi_work work; |
Christoph Hellwig | f0fad8a | 2009-09-11 09:47:56 +0200 | [diff] [blame] | 235 | |
Jens Axboe | b6e5131 | 2009-09-16 15:13:54 +0200 | [diff] [blame] | 236 | bdi_work_init(&work, &args); |
| 237 | work.state |= WS_ONSTACK; |
Christoph Hellwig | f0fad8a | 2009-09-11 09:47:56 +0200 | [diff] [blame] | 238 | |
Jens Axboe | b6e5131 | 2009-09-16 15:13:54 +0200 | [diff] [blame] | 239 | bdi_queue_work(bdi, &work); |
| 240 | bdi_wait_on_work_clear(&work); |
| 241 | } |
| 242 | |
| 243 | /** |
| 244 | * bdi_start_writeback - start writeback |
| 245 | * @bdi: the backing device to write from |
Jaswinder Singh Rajput | 4b6764f | 2010-01-01 20:35:23 -0800 | [diff] [blame] | 246 | * @sb: write inodes from this super_block |
Jens Axboe | b6e5131 | 2009-09-16 15:13:54 +0200 | [diff] [blame] | 247 | * @nr_pages: the number of pages to write |
| 248 | * |
| 249 | * Description: |
| 250 | * This does WB_SYNC_NONE opportunistic writeback. The IO is only |
| 251 | * started when this function returns, we make no guarentees on |
Jens Axboe | 0e3c9a2 | 2010-06-01 11:08:43 +0200 | [diff] [blame^] | 252 | * completion. Caller need not hold sb s_umount semaphore. |
Jens Axboe | b6e5131 | 2009-09-16 15:13:54 +0200 | [diff] [blame] | 253 | * |
| 254 | */ |
Jens Axboe | a72bfd4 | 2009-09-26 00:07:46 +0200 | [diff] [blame] | 255 | void bdi_start_writeback(struct backing_dev_info *bdi, struct super_block *sb, |
Jens Axboe | 0e3c9a2 | 2010-06-01 11:08:43 +0200 | [diff] [blame^] | 256 | long nr_pages) |
Jens Axboe | b6e5131 | 2009-09-16 15:13:54 +0200 | [diff] [blame] | 257 | { |
| 258 | struct wb_writeback_args args = { |
Jens Axboe | a72bfd4 | 2009-09-26 00:07:46 +0200 | [diff] [blame] | 259 | .sb = sb, |
Jens Axboe | b6e5131 | 2009-09-16 15:13:54 +0200 | [diff] [blame] | 260 | .sync_mode = WB_SYNC_NONE, |
| 261 | .nr_pages = nr_pages, |
| 262 | .range_cyclic = 1, |
| 263 | }; |
| 264 | |
Wu Fengguang | d3ddec7 | 2009-09-23 20:33:40 +0800 | [diff] [blame] | 265 | /* |
| 266 | * We treat @nr_pages=0 as the special case to do background writeback, |
| 267 | * ie. to sync pages until the background dirty threshold is reached. |
| 268 | */ |
| 269 | if (!nr_pages) { |
| 270 | args.nr_pages = LONG_MAX; |
| 271 | args.for_background = 1; |
| 272 | } |
| 273 | |
Jens Axboe | f17625b | 2010-06-01 11:05:22 +0200 | [diff] [blame] | 274 | bdi_alloc_queue_work(bdi, &args); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 275 | } |
| 276 | |
| 277 | /* |
Andrew Morton | 6610a0b | 2007-10-16 23:30:32 -0700 | [diff] [blame] | 278 | * Redirty an inode: set its when-it-was dirtied timestamp and move it to the |
| 279 | * furthest end of its superblock's dirty-inode list. |
| 280 | * |
| 281 | * 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] | 282 | * 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] | 283 | * the case then the inode must have been redirtied while it was being written |
| 284 | * out and we don't reset its dirtied_when. |
| 285 | */ |
| 286 | static void redirty_tail(struct inode *inode) |
| 287 | { |
Jens Axboe | 03ba378 | 2009-09-09 09:08:54 +0200 | [diff] [blame] | 288 | struct bdi_writeback *wb = &inode_to_bdi(inode)->wb; |
Andrew Morton | 6610a0b | 2007-10-16 23:30:32 -0700 | [diff] [blame] | 289 | |
Jens Axboe | 03ba378 | 2009-09-09 09:08:54 +0200 | [diff] [blame] | 290 | if (!list_empty(&wb->b_dirty)) { |
Jens Axboe | 66f3b8e | 2009-09-02 09:19:46 +0200 | [diff] [blame] | 291 | struct inode *tail; |
Andrew Morton | 6610a0b | 2007-10-16 23:30:32 -0700 | [diff] [blame] | 292 | |
Jens Axboe | 03ba378 | 2009-09-09 09:08:54 +0200 | [diff] [blame] | 293 | tail = list_entry(wb->b_dirty.next, struct inode, i_list); |
Jens Axboe | 66f3b8e | 2009-09-02 09:19:46 +0200 | [diff] [blame] | 294 | if (time_before(inode->dirtied_when, tail->dirtied_when)) |
Andrew Morton | 6610a0b | 2007-10-16 23:30:32 -0700 | [diff] [blame] | 295 | inode->dirtied_when = jiffies; |
| 296 | } |
Jens Axboe | 03ba378 | 2009-09-09 09:08:54 +0200 | [diff] [blame] | 297 | list_move(&inode->i_list, &wb->b_dirty); |
Andrew Morton | 6610a0b | 2007-10-16 23:30:32 -0700 | [diff] [blame] | 298 | } |
| 299 | |
| 300 | /* |
Jens Axboe | 66f3b8e | 2009-09-02 09:19:46 +0200 | [diff] [blame] | 301 | * requeue inode for re-scanning after bdi->b_io list is exhausted. |
Andrew Morton | c986d1e | 2007-10-16 23:30:34 -0700 | [diff] [blame] | 302 | */ |
Ken Chen | 0e0f4fc | 2007-10-16 23:30:38 -0700 | [diff] [blame] | 303 | static void requeue_io(struct inode *inode) |
Andrew Morton | c986d1e | 2007-10-16 23:30:34 -0700 | [diff] [blame] | 304 | { |
Jens Axboe | 03ba378 | 2009-09-09 09:08:54 +0200 | [diff] [blame] | 305 | struct bdi_writeback *wb = &inode_to_bdi(inode)->wb; |
| 306 | |
| 307 | list_move(&inode->i_list, &wb->b_more_io); |
Andrew Morton | c986d1e | 2007-10-16 23:30:34 -0700 | [diff] [blame] | 308 | } |
| 309 | |
Joern Engel | 1c0eeaf | 2007-10-16 23:30:44 -0700 | [diff] [blame] | 310 | static void inode_sync_complete(struct inode *inode) |
| 311 | { |
| 312 | /* |
| 313 | * Prevent speculative execution through spin_unlock(&inode_lock); |
| 314 | */ |
| 315 | smp_mb(); |
| 316 | wake_up_bit(&inode->i_state, __I_SYNC); |
| 317 | } |
| 318 | |
Jeff Layton | d2caa3c5 | 2009-04-02 16:56:37 -0700 | [diff] [blame] | 319 | static bool inode_dirtied_after(struct inode *inode, unsigned long t) |
| 320 | { |
| 321 | bool ret = time_after(inode->dirtied_when, t); |
| 322 | #ifndef CONFIG_64BIT |
| 323 | /* |
| 324 | * For inodes being constantly redirtied, dirtied_when can get stuck. |
| 325 | * It _appears_ to be in the future, but is actually in distant past. |
| 326 | * This test is necessary to prevent such wrapped-around relative times |
Jens Axboe | 5b0830c | 2009-09-23 19:37:09 +0200 | [diff] [blame] | 327 | * from permanently stopping the whole bdi writeback. |
Jeff Layton | d2caa3c5 | 2009-04-02 16:56:37 -0700 | [diff] [blame] | 328 | */ |
| 329 | ret = ret && time_before_eq(inode->dirtied_when, jiffies); |
| 330 | #endif |
| 331 | return ret; |
| 332 | } |
| 333 | |
Andrew Morton | c986d1e | 2007-10-16 23:30:34 -0700 | [diff] [blame] | 334 | /* |
Fengguang Wu | 2c13657 | 2007-10-16 23:30:39 -0700 | [diff] [blame] | 335 | * Move expired dirty inodes from @delaying_queue to @dispatch_queue. |
| 336 | */ |
| 337 | static void move_expired_inodes(struct list_head *delaying_queue, |
| 338 | struct list_head *dispatch_queue, |
| 339 | unsigned long *older_than_this) |
| 340 | { |
Shaohua Li | 5c03449 | 2009-09-24 14:42:33 +0200 | [diff] [blame] | 341 | LIST_HEAD(tmp); |
| 342 | struct list_head *pos, *node; |
Jens Axboe | cf13730 | 2009-09-24 15:12:57 +0200 | [diff] [blame] | 343 | struct super_block *sb = NULL; |
Shaohua Li | 5c03449 | 2009-09-24 14:42:33 +0200 | [diff] [blame] | 344 | struct inode *inode; |
Jens Axboe | cf13730 | 2009-09-24 15:12:57 +0200 | [diff] [blame] | 345 | int do_sb_sort = 0; |
Shaohua Li | 5c03449 | 2009-09-24 14:42:33 +0200 | [diff] [blame] | 346 | |
Fengguang Wu | 2c13657 | 2007-10-16 23:30:39 -0700 | [diff] [blame] | 347 | while (!list_empty(delaying_queue)) { |
Shaohua Li | 5c03449 | 2009-09-24 14:42:33 +0200 | [diff] [blame] | 348 | inode = list_entry(delaying_queue->prev, struct inode, i_list); |
Fengguang Wu | 2c13657 | 2007-10-16 23:30:39 -0700 | [diff] [blame] | 349 | if (older_than_this && |
Jeff Layton | d2caa3c5 | 2009-04-02 16:56:37 -0700 | [diff] [blame] | 350 | inode_dirtied_after(inode, *older_than_this)) |
Fengguang Wu | 2c13657 | 2007-10-16 23:30:39 -0700 | [diff] [blame] | 351 | break; |
Jens Axboe | cf13730 | 2009-09-24 15:12:57 +0200 | [diff] [blame] | 352 | if (sb && sb != inode->i_sb) |
| 353 | do_sb_sort = 1; |
| 354 | sb = inode->i_sb; |
Shaohua Li | 5c03449 | 2009-09-24 14:42:33 +0200 | [diff] [blame] | 355 | list_move(&inode->i_list, &tmp); |
| 356 | } |
| 357 | |
Jens Axboe | cf13730 | 2009-09-24 15:12:57 +0200 | [diff] [blame] | 358 | /* just one sb in list, splice to dispatch_queue and we're done */ |
| 359 | if (!do_sb_sort) { |
| 360 | list_splice(&tmp, dispatch_queue); |
| 361 | return; |
| 362 | } |
| 363 | |
Shaohua Li | 5c03449 | 2009-09-24 14:42:33 +0200 | [diff] [blame] | 364 | /* Move inodes from one superblock together */ |
| 365 | while (!list_empty(&tmp)) { |
| 366 | inode = list_entry(tmp.prev, struct inode, i_list); |
| 367 | sb = inode->i_sb; |
| 368 | list_for_each_prev_safe(pos, node, &tmp) { |
| 369 | inode = list_entry(pos, struct inode, i_list); |
| 370 | if (inode->i_sb == sb) |
| 371 | list_move(&inode->i_list, dispatch_queue); |
| 372 | } |
Fengguang Wu | 2c13657 | 2007-10-16 23:30:39 -0700 | [diff] [blame] | 373 | } |
| 374 | } |
| 375 | |
| 376 | /* |
| 377 | * Queue all expired dirty inodes for io, eldest first. |
| 378 | */ |
Jens Axboe | 03ba378 | 2009-09-09 09:08:54 +0200 | [diff] [blame] | 379 | 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] | 380 | { |
Jens Axboe | 03ba378 | 2009-09-09 09:08:54 +0200 | [diff] [blame] | 381 | list_splice_init(&wb->b_more_io, wb->b_io.prev); |
| 382 | move_expired_inodes(&wb->b_dirty, &wb->b_io, older_than_this); |
Jens Axboe | 66f3b8e | 2009-09-02 09:19:46 +0200 | [diff] [blame] | 383 | } |
| 384 | |
Christoph Hellwig | a9185b4 | 2010-03-05 09:21:37 +0100 | [diff] [blame] | 385 | static int write_inode(struct inode *inode, struct writeback_control *wbc) |
Jens Axboe | 66f3b8e | 2009-09-02 09:19:46 +0200 | [diff] [blame] | 386 | { |
Jens Axboe | 03ba378 | 2009-09-09 09:08:54 +0200 | [diff] [blame] | 387 | if (inode->i_sb->s_op->write_inode && !is_bad_inode(inode)) |
Christoph Hellwig | a9185b4 | 2010-03-05 09:21:37 +0100 | [diff] [blame] | 388 | return inode->i_sb->s_op->write_inode(inode, wbc); |
Jens Axboe | 03ba378 | 2009-09-09 09:08:54 +0200 | [diff] [blame] | 389 | return 0; |
Fengguang Wu | 2c13657 | 2007-10-16 23:30:39 -0700 | [diff] [blame] | 390 | } |
| 391 | |
| 392 | /* |
Christoph Hellwig | 01c0319 | 2009-06-08 13:35:40 +0200 | [diff] [blame] | 393 | * Wait for writeback on an inode to complete. |
| 394 | */ |
| 395 | static void inode_wait_for_writeback(struct inode *inode) |
| 396 | { |
| 397 | DEFINE_WAIT_BIT(wq, &inode->i_state, __I_SYNC); |
| 398 | wait_queue_head_t *wqh; |
| 399 | |
| 400 | wqh = bit_waitqueue(&inode->i_state, __I_SYNC); |
| 401 | do { |
| 402 | spin_unlock(&inode_lock); |
| 403 | __wait_on_bit(wqh, &wq, inode_wait, TASK_UNINTERRUPTIBLE); |
| 404 | spin_lock(&inode_lock); |
| 405 | } while (inode->i_state & I_SYNC); |
| 406 | } |
| 407 | |
| 408 | /* |
| 409 | * Write out an inode's dirty pages. Called under inode_lock. Either the |
| 410 | * caller has ref on the inode (either via __iget or via syscall against an fd) |
| 411 | * or the inode has I_WILL_FREE set (via generic_forget_inode) |
| 412 | * |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 413 | * If `wait' is set, wait on the writeout. |
| 414 | * |
| 415 | * The whole writeout design is quite complex and fragile. We want to avoid |
| 416 | * starvation of particular inodes when others are being redirtied, prevent |
| 417 | * livelocks, etc. |
| 418 | * |
| 419 | * Called under inode_lock. |
| 420 | */ |
| 421 | static int |
Christoph Hellwig | 01c0319 | 2009-06-08 13:35:40 +0200 | [diff] [blame] | 422 | writeback_single_inode(struct inode *inode, struct writeback_control *wbc) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 423 | { |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 424 | struct address_space *mapping = inode->i_mapping; |
Christoph Hellwig | 01c0319 | 2009-06-08 13:35:40 +0200 | [diff] [blame] | 425 | unsigned dirty; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 426 | int ret; |
| 427 | |
Christoph Hellwig | 01c0319 | 2009-06-08 13:35:40 +0200 | [diff] [blame] | 428 | if (!atomic_read(&inode->i_count)) |
| 429 | WARN_ON(!(inode->i_state & (I_WILL_FREE|I_FREEING))); |
| 430 | else |
| 431 | WARN_ON(inode->i_state & I_WILL_FREE); |
| 432 | |
| 433 | if (inode->i_state & I_SYNC) { |
| 434 | /* |
| 435 | * If this inode is locked for writeback and we are not doing |
Jens Axboe | 66f3b8e | 2009-09-02 09:19:46 +0200 | [diff] [blame] | 436 | * writeback-for-data-integrity, move it to b_more_io so that |
Christoph Hellwig | 01c0319 | 2009-06-08 13:35:40 +0200 | [diff] [blame] | 437 | * writeback can proceed with the other inodes on s_io. |
| 438 | * |
| 439 | * We'll have another go at writing back this inode when we |
Jens Axboe | 66f3b8e | 2009-09-02 09:19:46 +0200 | [diff] [blame] | 440 | * completed a full scan of b_io. |
Christoph Hellwig | 01c0319 | 2009-06-08 13:35:40 +0200 | [diff] [blame] | 441 | */ |
Christoph Hellwig | a9185b4 | 2010-03-05 09:21:37 +0100 | [diff] [blame] | 442 | if (wbc->sync_mode != WB_SYNC_ALL) { |
Christoph Hellwig | 01c0319 | 2009-06-08 13:35:40 +0200 | [diff] [blame] | 443 | requeue_io(inode); |
| 444 | return 0; |
| 445 | } |
| 446 | |
| 447 | /* |
| 448 | * It's a data-integrity sync. We must wait. |
| 449 | */ |
| 450 | inode_wait_for_writeback(inode); |
| 451 | } |
| 452 | |
Joern Engel | 1c0eeaf | 2007-10-16 23:30:44 -0700 | [diff] [blame] | 453 | BUG_ON(inode->i_state & I_SYNC); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 454 | |
Dmitry Monakhov | 5547e8a | 2010-05-07 13:35:44 +0400 | [diff] [blame] | 455 | /* Set I_SYNC, reset I_DIRTY_PAGES */ |
Joern Engel | 1c0eeaf | 2007-10-16 23:30:44 -0700 | [diff] [blame] | 456 | inode->i_state |= I_SYNC; |
Dmitry Monakhov | 5547e8a | 2010-05-07 13:35:44 +0400 | [diff] [blame] | 457 | inode->i_state &= ~I_DIRTY_PAGES; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 458 | spin_unlock(&inode_lock); |
| 459 | |
| 460 | ret = do_writepages(mapping, wbc); |
| 461 | |
Christoph Hellwig | 26821ed | 2010-03-05 09:21:21 +0100 | [diff] [blame] | 462 | /* |
| 463 | * Make sure to wait on the data before writing out the metadata. |
| 464 | * This is important for filesystems that modify metadata on data |
| 465 | * I/O completion. |
| 466 | */ |
Christoph Hellwig | a9185b4 | 2010-03-05 09:21:37 +0100 | [diff] [blame] | 467 | if (wbc->sync_mode == WB_SYNC_ALL) { |
Christoph Hellwig | 26821ed | 2010-03-05 09:21:21 +0100 | [diff] [blame] | 468 | int err = filemap_fdatawait(mapping); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 469 | if (ret == 0) |
| 470 | ret = err; |
| 471 | } |
| 472 | |
Dmitry Monakhov | 5547e8a | 2010-05-07 13:35:44 +0400 | [diff] [blame] | 473 | /* |
| 474 | * Some filesystems may redirty the inode during the writeback |
| 475 | * due to delalloc, clear dirty metadata flags right before |
| 476 | * write_inode() |
| 477 | */ |
| 478 | spin_lock(&inode_lock); |
| 479 | dirty = inode->i_state & I_DIRTY; |
| 480 | inode->i_state &= ~(I_DIRTY_SYNC | I_DIRTY_DATASYNC); |
| 481 | spin_unlock(&inode_lock); |
Christoph Hellwig | 26821ed | 2010-03-05 09:21:21 +0100 | [diff] [blame] | 482 | /* Don't write the inode if only I_DIRTY_PAGES was set */ |
| 483 | if (dirty & (I_DIRTY_SYNC | I_DIRTY_DATASYNC)) { |
Christoph Hellwig | a9185b4 | 2010-03-05 09:21:37 +0100 | [diff] [blame] | 484 | int err = write_inode(inode, wbc); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 485 | if (ret == 0) |
| 486 | ret = err; |
| 487 | } |
| 488 | |
| 489 | spin_lock(&inode_lock); |
Joern Engel | 1c0eeaf | 2007-10-16 23:30:44 -0700 | [diff] [blame] | 490 | inode->i_state &= ~I_SYNC; |
Wu Fengguang | 84a8924 | 2009-06-16 15:33:17 -0700 | [diff] [blame] | 491 | if (!(inode->i_state & (I_FREEING | I_CLEAR))) { |
Wu Fengguang | b3af946 | 2009-09-25 06:04:10 +0200 | [diff] [blame] | 492 | if ((inode->i_state & I_DIRTY_PAGES) && wbc->for_kupdate) { |
Wu Fengguang | ae1b7f7 | 2009-09-23 20:33:42 +0800 | [diff] [blame] | 493 | /* |
Wu Fengguang | b3af946 | 2009-09-25 06:04:10 +0200 | [diff] [blame] | 494 | * More pages get dirtied by a fast dirtier. |
| 495 | */ |
| 496 | goto select_queue; |
| 497 | } else if (inode->i_state & I_DIRTY) { |
| 498 | /* |
| 499 | * At least XFS will redirty the inode during the |
| 500 | * writeback (delalloc) and on io completion (isize). |
Wu Fengguang | ae1b7f7 | 2009-09-23 20:33:42 +0800 | [diff] [blame] | 501 | */ |
| 502 | redirty_tail(inode); |
| 503 | } else if (mapping_tagged(mapping, PAGECACHE_TAG_DIRTY)) { |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 504 | /* |
| 505 | * We didn't write back all the pages. nfs_writepages() |
| 506 | * sometimes bales out without doing anything. Redirty |
Jens Axboe | 66f3b8e | 2009-09-02 09:19:46 +0200 | [diff] [blame] | 507 | * 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] | 508 | */ |
| 509 | /* |
| 510 | * akpm: if the caller was the kupdate function we put |
Jens Axboe | 66f3b8e | 2009-09-02 09:19:46 +0200 | [diff] [blame] | 511 | * this inode at the head of b_dirty so it gets first |
Andrew Morton | 1b43ef9 | 2007-10-16 23:30:35 -0700 | [diff] [blame] | 512 | * consideration. Otherwise, move it to the tail, for |
| 513 | * the reasons described there. I'm not really sure |
| 514 | * how much sense this makes. Presumably I had a good |
| 515 | * reasons for doing it this way, and I'd rather not |
| 516 | * muck with it at present. |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 517 | */ |
| 518 | if (wbc->for_kupdate) { |
| 519 | /* |
Fengguang Wu | 2c13657 | 2007-10-16 23:30:39 -0700 | [diff] [blame] | 520 | * For the kupdate function we move the inode |
Jens Axboe | 66f3b8e | 2009-09-02 09:19:46 +0200 | [diff] [blame] | 521 | * to b_more_io so it will get more writeout as |
Fengguang Wu | 2c13657 | 2007-10-16 23:30:39 -0700 | [diff] [blame] | 522 | * soon as the queue becomes uncongested. |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 523 | */ |
| 524 | inode->i_state |= I_DIRTY_PAGES; |
Wu Fengguang | b3af946 | 2009-09-25 06:04:10 +0200 | [diff] [blame] | 525 | select_queue: |
Fengguang Wu | 8bc3be2 | 2008-02-04 22:29:36 -0800 | [diff] [blame] | 526 | if (wbc->nr_to_write <= 0) { |
| 527 | /* |
| 528 | * slice used up: queue for next turn |
| 529 | */ |
| 530 | requeue_io(inode); |
| 531 | } else { |
| 532 | /* |
| 533 | * somehow blocked: retry later |
| 534 | */ |
| 535 | redirty_tail(inode); |
| 536 | } |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 537 | } else { |
| 538 | /* |
| 539 | * Otherwise fully redirty the inode so that |
| 540 | * other inodes on this superblock will get some |
| 541 | * writeout. Otherwise heavy writing to one |
| 542 | * file would indefinitely suspend writeout of |
| 543 | * all the other files. |
| 544 | */ |
| 545 | inode->i_state |= I_DIRTY_PAGES; |
Andrew Morton | 1b43ef9 | 2007-10-16 23:30:35 -0700 | [diff] [blame] | 546 | redirty_tail(inode); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 547 | } |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 548 | } else if (atomic_read(&inode->i_count)) { |
| 549 | /* |
| 550 | * The inode is clean, inuse |
| 551 | */ |
| 552 | list_move(&inode->i_list, &inode_in_use); |
| 553 | } else { |
| 554 | /* |
| 555 | * The inode is clean, unused |
| 556 | */ |
| 557 | list_move(&inode->i_list, &inode_unused); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 558 | } |
| 559 | } |
Joern Engel | 1c0eeaf | 2007-10-16 23:30:44 -0700 | [diff] [blame] | 560 | inode_sync_complete(inode); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 561 | return ret; |
| 562 | } |
| 563 | |
Edward Shishkin | f11c9c5 | 2010-03-11 14:09:47 -0800 | [diff] [blame] | 564 | static void unpin_sb_for_writeback(struct super_block *sb) |
Jens Axboe | 9ecc273 | 2009-09-24 15:25:11 +0200 | [diff] [blame] | 565 | { |
Edward Shishkin | f11c9c5 | 2010-03-11 14:09:47 -0800 | [diff] [blame] | 566 | up_read(&sb->s_umount); |
| 567 | put_super(sb); |
Jens Axboe | 9ecc273 | 2009-09-24 15:25:11 +0200 | [diff] [blame] | 568 | } |
| 569 | |
Edward Shishkin | f11c9c5 | 2010-03-11 14:09:47 -0800 | [diff] [blame] | 570 | enum sb_pin_state { |
| 571 | SB_PINNED, |
| 572 | SB_NOT_PINNED, |
| 573 | SB_PIN_FAILED |
| 574 | }; |
| 575 | |
Jens Axboe | 03ba378 | 2009-09-09 09:08:54 +0200 | [diff] [blame] | 576 | /* |
| 577 | * For WB_SYNC_NONE writeback, the caller does not have the sb pinned |
| 578 | * before calling writeback. So make sure that we do pin it, so it doesn't |
| 579 | * go away while we are writing inodes from it. |
Jens Axboe | 03ba378 | 2009-09-09 09:08:54 +0200 | [diff] [blame] | 580 | */ |
Edward Shishkin | f11c9c5 | 2010-03-11 14:09:47 -0800 | [diff] [blame] | 581 | static enum sb_pin_state pin_sb_for_writeback(struct writeback_control *wbc, |
| 582 | struct super_block *sb) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 583 | { |
Jens Axboe | 9ecc273 | 2009-09-24 15:25:11 +0200 | [diff] [blame] | 584 | /* |
Jens Axboe | 03ba378 | 2009-09-09 09:08:54 +0200 | [diff] [blame] | 585 | * Caller must already hold the ref for this |
| 586 | */ |
Jens Axboe | 0e3c9a2 | 2010-06-01 11:08:43 +0200 | [diff] [blame^] | 587 | if (wbc->sync_mode == WB_SYNC_ALL) { |
Jens Axboe | 03ba378 | 2009-09-09 09:08:54 +0200 | [diff] [blame] | 588 | WARN_ON(!rwsem_is_locked(&sb->s_umount)); |
Edward Shishkin | f11c9c5 | 2010-03-11 14:09:47 -0800 | [diff] [blame] | 589 | return SB_NOT_PINNED; |
Jens Axboe | 03ba378 | 2009-09-09 09:08:54 +0200 | [diff] [blame] | 590 | } |
Jens Axboe | 03ba378 | 2009-09-09 09:08:54 +0200 | [diff] [blame] | 591 | spin_lock(&sb_lock); |
| 592 | sb->s_count++; |
| 593 | if (down_read_trylock(&sb->s_umount)) { |
| 594 | if (sb->s_root) { |
| 595 | spin_unlock(&sb_lock); |
Edward Shishkin | f11c9c5 | 2010-03-11 14:09:47 -0800 | [diff] [blame] | 596 | return SB_PINNED; |
Jens Axboe | 03ba378 | 2009-09-09 09:08:54 +0200 | [diff] [blame] | 597 | } |
| 598 | /* |
| 599 | * umounted, drop rwsem again and fall through to failure |
| 600 | */ |
| 601 | up_read(&sb->s_umount); |
| 602 | } |
Jens Axboe | 03ba378 | 2009-09-09 09:08:54 +0200 | [diff] [blame] | 603 | sb->s_count--; |
| 604 | spin_unlock(&sb_lock); |
Edward Shishkin | f11c9c5 | 2010-03-11 14:09:47 -0800 | [diff] [blame] | 605 | return SB_PIN_FAILED; |
Jens Axboe | 03ba378 | 2009-09-09 09:08:54 +0200 | [diff] [blame] | 606 | } |
| 607 | |
Edward Shishkin | f11c9c5 | 2010-03-11 14:09:47 -0800 | [diff] [blame] | 608 | /* |
| 609 | * Write a portion of b_io inodes which belong to @sb. |
| 610 | * If @wbc->sb != NULL, then find and write all such |
| 611 | * inodes. Otherwise write only ones which go sequentially |
| 612 | * in reverse order. |
| 613 | * Return 1, if the caller writeback routine should be |
| 614 | * interrupted. Otherwise return 0. |
| 615 | */ |
| 616 | static int writeback_sb_inodes(struct super_block *sb, |
| 617 | struct bdi_writeback *wb, |
| 618 | struct writeback_control *wbc) |
Jens Axboe | 03ba378 | 2009-09-09 09:08:54 +0200 | [diff] [blame] | 619 | { |
Jens Axboe | 03ba378 | 2009-09-09 09:08:54 +0200 | [diff] [blame] | 620 | while (!list_empty(&wb->b_io)) { |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 621 | long pages_skipped; |
Edward Shishkin | f11c9c5 | 2010-03-11 14:09:47 -0800 | [diff] [blame] | 622 | struct inode *inode = list_entry(wb->b_io.prev, |
| 623 | struct inode, i_list); |
| 624 | if (wbc->sb && sb != inode->i_sb) { |
| 625 | /* super block given and doesn't |
| 626 | match, skip this inode */ |
Jens Axboe | 66f3b8e | 2009-09-02 09:19:46 +0200 | [diff] [blame] | 627 | redirty_tail(inode); |
| 628 | continue; |
| 629 | } |
Edward Shishkin | f11c9c5 | 2010-03-11 14:09:47 -0800 | [diff] [blame] | 630 | if (sb != inode->i_sb) |
| 631 | /* finish with this superblock */ |
| 632 | return 0; |
Wu Fengguang | 84a8924 | 2009-06-16 15:33:17 -0700 | [diff] [blame] | 633 | if (inode->i_state & (I_NEW | I_WILL_FREE)) { |
Nick Piggin | 7ef0d73 | 2009-03-12 14:31:38 -0700 | [diff] [blame] | 634 | requeue_io(inode); |
| 635 | continue; |
| 636 | } |
Jeff Layton | d2caa3c5 | 2009-04-02 16:56:37 -0700 | [diff] [blame] | 637 | /* |
| 638 | * Was this inode dirtied after sync_sb_inodes was called? |
| 639 | * This keeps sync from extra jobs and livelock. |
| 640 | */ |
Edward Shishkin | f11c9c5 | 2010-03-11 14:09:47 -0800 | [diff] [blame] | 641 | if (inode_dirtied_after(inode, wbc->wb_start)) |
| 642 | return 1; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 643 | |
Wu Fengguang | 84a8924 | 2009-06-16 15:33:17 -0700 | [diff] [blame] | 644 | BUG_ON(inode->i_state & (I_FREEING | I_CLEAR)); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 645 | __iget(inode); |
| 646 | pages_skipped = wbc->pages_skipped; |
Christoph Hellwig | 01c0319 | 2009-06-08 13:35:40 +0200 | [diff] [blame] | 647 | writeback_single_inode(inode, wbc); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 648 | if (wbc->pages_skipped != pages_skipped) { |
| 649 | /* |
| 650 | * writeback is not making progress due to locked |
| 651 | * buffers. Skip this inode for now. |
| 652 | */ |
Andrew Morton | f57b9b7 | 2007-10-16 23:30:34 -0700 | [diff] [blame] | 653 | redirty_tail(inode); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 654 | } |
| 655 | spin_unlock(&inode_lock); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 656 | iput(inode); |
OGAWA Hirofumi | 4ffc844 | 2006-03-25 03:07:44 -0800 | [diff] [blame] | 657 | cond_resched(); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 658 | spin_lock(&inode_lock); |
Fengguang Wu | 8bc3be2 | 2008-02-04 22:29:36 -0800 | [diff] [blame] | 659 | if (wbc->nr_to_write <= 0) { |
| 660 | wbc->more_io = 1; |
Edward Shishkin | f11c9c5 | 2010-03-11 14:09:47 -0800 | [diff] [blame] | 661 | return 1; |
Fengguang Wu | 8bc3be2 | 2008-02-04 22:29:36 -0800 | [diff] [blame] | 662 | } |
Jens Axboe | 03ba378 | 2009-09-09 09:08:54 +0200 | [diff] [blame] | 663 | if (!list_empty(&wb->b_more_io)) |
Fengguang Wu | 8bc3be2 | 2008-02-04 22:29:36 -0800 | [diff] [blame] | 664 | wbc->more_io = 1; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 665 | } |
Edward Shishkin | f11c9c5 | 2010-03-11 14:09:47 -0800 | [diff] [blame] | 666 | /* b_io is empty */ |
| 667 | return 1; |
| 668 | } |
Nick Piggin | 38f2197 | 2009-01-06 14:40:25 -0800 | [diff] [blame] | 669 | |
Edward Shishkin | f11c9c5 | 2010-03-11 14:09:47 -0800 | [diff] [blame] | 670 | static void writeback_inodes_wb(struct bdi_writeback *wb, |
| 671 | struct writeback_control *wbc) |
| 672 | { |
| 673 | int ret = 0; |
Jens Axboe | 9ecc273 | 2009-09-24 15:25:11 +0200 | [diff] [blame] | 674 | |
Edward Shishkin | f11c9c5 | 2010-03-11 14:09:47 -0800 | [diff] [blame] | 675 | wbc->wb_start = jiffies; /* livelock avoidance */ |
| 676 | spin_lock(&inode_lock); |
| 677 | if (!wbc->for_kupdate || list_empty(&wb->b_io)) |
| 678 | queue_io(wb, wbc->older_than_this); |
| 679 | |
| 680 | while (!list_empty(&wb->b_io)) { |
| 681 | struct inode *inode = list_entry(wb->b_io.prev, |
| 682 | struct inode, i_list); |
| 683 | struct super_block *sb = inode->i_sb; |
| 684 | enum sb_pin_state state; |
| 685 | |
| 686 | if (wbc->sb && sb != wbc->sb) { |
| 687 | /* super block given and doesn't |
| 688 | match, skip this inode */ |
| 689 | redirty_tail(inode); |
| 690 | continue; |
| 691 | } |
| 692 | state = pin_sb_for_writeback(wbc, sb); |
| 693 | |
| 694 | if (state == SB_PIN_FAILED) { |
| 695 | requeue_io(inode); |
| 696 | continue; |
| 697 | } |
| 698 | ret = writeback_sb_inodes(sb, wb, wbc); |
| 699 | |
| 700 | if (state == SB_PINNED) |
| 701 | unpin_sb_for_writeback(sb); |
| 702 | if (ret) |
| 703 | break; |
| 704 | } |
Jens Axboe | 66f3b8e | 2009-09-02 09:19:46 +0200 | [diff] [blame] | 705 | spin_unlock(&inode_lock); |
| 706 | /* Leave any unwritten inodes on b_io */ |
| 707 | } |
| 708 | |
Jens Axboe | 03ba378 | 2009-09-09 09:08:54 +0200 | [diff] [blame] | 709 | void writeback_inodes_wbc(struct writeback_control *wbc) |
| 710 | { |
| 711 | struct backing_dev_info *bdi = wbc->bdi; |
| 712 | |
| 713 | writeback_inodes_wb(&bdi->wb, wbc); |
| 714 | } |
| 715 | |
| 716 | /* |
| 717 | * The maximum number of pages to writeout in a single bdi flush/kupdate |
| 718 | * operation. We do this so we don't hold I_SYNC against an inode for |
| 719 | * enormous amounts of time, which would block a userspace task which has |
| 720 | * been forced to throttle against that inode. Also, the code reevaluates |
| 721 | * the dirty each time it has written this many pages. |
| 722 | */ |
| 723 | #define MAX_WRITEBACK_PAGES 1024 |
| 724 | |
| 725 | static inline bool over_bground_thresh(void) |
| 726 | { |
| 727 | unsigned long background_thresh, dirty_thresh; |
| 728 | |
| 729 | get_dirty_limits(&background_thresh, &dirty_thresh, NULL, NULL); |
| 730 | |
| 731 | return (global_page_state(NR_FILE_DIRTY) + |
| 732 | global_page_state(NR_UNSTABLE_NFS) >= background_thresh); |
| 733 | } |
| 734 | |
| 735 | /* |
| 736 | * Explicit flushing or periodic writeback of "old" data. |
| 737 | * |
| 738 | * Define "old": the first time one of an inode's pages is dirtied, we mark the |
| 739 | * dirtying-time in the inode's address_space. So this periodic writeback code |
| 740 | * just walks the superblock inode list, writing back any inodes which are |
| 741 | * older than a specific point in time. |
| 742 | * |
| 743 | * Try to run once per dirty_writeback_interval. But if a writeback event |
| 744 | * takes longer than a dirty_writeback_interval interval, then leave a |
| 745 | * one-second gap. |
| 746 | * |
| 747 | * older_than_this takes precedence over nr_to_write. So we'll only write back |
| 748 | * all dirty pages if they are all attached to "old" mappings. |
| 749 | */ |
Jens Axboe | c4a77a6 | 2009-09-16 15:18:25 +0200 | [diff] [blame] | 750 | static long wb_writeback(struct bdi_writeback *wb, |
| 751 | struct wb_writeback_args *args) |
Jens Axboe | 03ba378 | 2009-09-09 09:08:54 +0200 | [diff] [blame] | 752 | { |
| 753 | struct writeback_control wbc = { |
| 754 | .bdi = wb->bdi, |
Jens Axboe | c4a77a6 | 2009-09-16 15:18:25 +0200 | [diff] [blame] | 755 | .sb = args->sb, |
| 756 | .sync_mode = args->sync_mode, |
Jens Axboe | 03ba378 | 2009-09-09 09:08:54 +0200 | [diff] [blame] | 757 | .older_than_this = NULL, |
Jens Axboe | c4a77a6 | 2009-09-16 15:18:25 +0200 | [diff] [blame] | 758 | .for_kupdate = args->for_kupdate, |
Wu Fengguang | b17621f | 2009-12-03 13:54:25 +0100 | [diff] [blame] | 759 | .for_background = args->for_background, |
Jens Axboe | c4a77a6 | 2009-09-16 15:18:25 +0200 | [diff] [blame] | 760 | .range_cyclic = args->range_cyclic, |
Jens Axboe | 03ba378 | 2009-09-09 09:08:54 +0200 | [diff] [blame] | 761 | }; |
| 762 | unsigned long oldest_jif; |
| 763 | long wrote = 0; |
Jan Kara | a5989bd | 2009-09-16 19:22:48 +0200 | [diff] [blame] | 764 | struct inode *inode; |
Jens Axboe | 03ba378 | 2009-09-09 09:08:54 +0200 | [diff] [blame] | 765 | |
| 766 | if (wbc.for_kupdate) { |
| 767 | wbc.older_than_this = &oldest_jif; |
| 768 | oldest_jif = jiffies - |
| 769 | msecs_to_jiffies(dirty_expire_interval * 10); |
| 770 | } |
Jens Axboe | c4a77a6 | 2009-09-16 15:18:25 +0200 | [diff] [blame] | 771 | if (!wbc.range_cyclic) { |
| 772 | wbc.range_start = 0; |
| 773 | wbc.range_end = LLONG_MAX; |
| 774 | } |
Jens Axboe | 03ba378 | 2009-09-09 09:08:54 +0200 | [diff] [blame] | 775 | |
| 776 | for (;;) { |
| 777 | /* |
Wu Fengguang | d3ddec7 | 2009-09-23 20:33:40 +0800 | [diff] [blame] | 778 | * Stop writeback when nr_pages has been consumed |
Jens Axboe | 03ba378 | 2009-09-09 09:08:54 +0200 | [diff] [blame] | 779 | */ |
Wu Fengguang | d3ddec7 | 2009-09-23 20:33:40 +0800 | [diff] [blame] | 780 | if (args->nr_pages <= 0) |
Jens Axboe | 03ba378 | 2009-09-09 09:08:54 +0200 | [diff] [blame] | 781 | break; |
| 782 | |
| 783 | /* |
Wu Fengguang | d3ddec7 | 2009-09-23 20:33:40 +0800 | [diff] [blame] | 784 | * For background writeout, stop when we are below the |
| 785 | * background dirty threshold |
Jens Axboe | 03ba378 | 2009-09-09 09:08:54 +0200 | [diff] [blame] | 786 | */ |
Wu Fengguang | d3ddec7 | 2009-09-23 20:33:40 +0800 | [diff] [blame] | 787 | if (args->for_background && !over_bground_thresh()) |
Jens Axboe | 03ba378 | 2009-09-09 09:08:54 +0200 | [diff] [blame] | 788 | break; |
| 789 | |
| 790 | wbc.more_io = 0; |
Jens Axboe | 03ba378 | 2009-09-09 09:08:54 +0200 | [diff] [blame] | 791 | wbc.nr_to_write = MAX_WRITEBACK_PAGES; |
| 792 | wbc.pages_skipped = 0; |
| 793 | writeback_inodes_wb(wb, &wbc); |
Jens Axboe | c4a77a6 | 2009-09-16 15:18:25 +0200 | [diff] [blame] | 794 | args->nr_pages -= MAX_WRITEBACK_PAGES - wbc.nr_to_write; |
Jens Axboe | 03ba378 | 2009-09-09 09:08:54 +0200 | [diff] [blame] | 795 | wrote += MAX_WRITEBACK_PAGES - wbc.nr_to_write; |
| 796 | |
| 797 | /* |
Jens Axboe | 71fd05a | 2009-09-23 19:32:26 +0200 | [diff] [blame] | 798 | * If we consumed everything, see if we have more |
Jens Axboe | 03ba378 | 2009-09-09 09:08:54 +0200 | [diff] [blame] | 799 | */ |
Jens Axboe | 71fd05a | 2009-09-23 19:32:26 +0200 | [diff] [blame] | 800 | if (wbc.nr_to_write <= 0) |
| 801 | continue; |
| 802 | /* |
| 803 | * Didn't write everything and we don't have more IO, bail |
| 804 | */ |
| 805 | if (!wbc.more_io) |
Jens Axboe | 03ba378 | 2009-09-09 09:08:54 +0200 | [diff] [blame] | 806 | break; |
Jens Axboe | 71fd05a | 2009-09-23 19:32:26 +0200 | [diff] [blame] | 807 | /* |
| 808 | * Did we write something? Try for more |
| 809 | */ |
| 810 | if (wbc.nr_to_write < MAX_WRITEBACK_PAGES) |
| 811 | continue; |
| 812 | /* |
| 813 | * Nothing written. Wait for some inode to |
| 814 | * become available for writeback. Otherwise |
| 815 | * we'll just busyloop. |
| 816 | */ |
| 817 | spin_lock(&inode_lock); |
| 818 | if (!list_empty(&wb->b_more_io)) { |
| 819 | inode = list_entry(wb->b_more_io.prev, |
| 820 | struct inode, i_list); |
| 821 | inode_wait_for_writeback(inode); |
Jens Axboe | 03ba378 | 2009-09-09 09:08:54 +0200 | [diff] [blame] | 822 | } |
Jens Axboe | 71fd05a | 2009-09-23 19:32:26 +0200 | [diff] [blame] | 823 | spin_unlock(&inode_lock); |
Jens Axboe | 03ba378 | 2009-09-09 09:08:54 +0200 | [diff] [blame] | 824 | } |
| 825 | |
| 826 | return wrote; |
| 827 | } |
| 828 | |
| 829 | /* |
| 830 | * 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] | 831 | * wb thread yet. ->seen is initially set for each thread that exists |
| 832 | * for this device, when a thread first notices a piece of work it |
| 833 | * clears its bit. Depending on writeback type, the thread will notify |
| 834 | * completion on either receiving the work (WB_SYNC_NONE) or after |
| 835 | * it is done (WB_SYNC_ALL). |
Jens Axboe | 03ba378 | 2009-09-09 09:08:54 +0200 | [diff] [blame] | 836 | */ |
| 837 | static struct bdi_work *get_next_work_item(struct backing_dev_info *bdi, |
| 838 | struct bdi_writeback *wb) |
| 839 | { |
| 840 | struct bdi_work *work, *ret = NULL; |
| 841 | |
| 842 | rcu_read_lock(); |
| 843 | |
| 844 | list_for_each_entry_rcu(work, &bdi->work_list, list) { |
Nick Piggin | 77fad5e | 2009-09-15 21:34:12 +0200 | [diff] [blame] | 845 | if (!test_bit(wb->nr, &work->seen)) |
Jens Axboe | 03ba378 | 2009-09-09 09:08:54 +0200 | [diff] [blame] | 846 | continue; |
Nick Piggin | 77fad5e | 2009-09-15 21:34:12 +0200 | [diff] [blame] | 847 | clear_bit(wb->nr, &work->seen); |
Jens Axboe | 03ba378 | 2009-09-09 09:08:54 +0200 | [diff] [blame] | 848 | |
| 849 | ret = work; |
| 850 | break; |
| 851 | } |
| 852 | |
| 853 | rcu_read_unlock(); |
| 854 | return ret; |
| 855 | } |
| 856 | |
| 857 | static long wb_check_old_data_flush(struct bdi_writeback *wb) |
| 858 | { |
| 859 | unsigned long expired; |
| 860 | long nr_pages; |
| 861 | |
Jens Axboe | 69b62d0 | 2010-05-17 12:51:03 +0200 | [diff] [blame] | 862 | /* |
| 863 | * When set to zero, disable periodic writeback |
| 864 | */ |
| 865 | if (!dirty_writeback_interval) |
| 866 | return 0; |
| 867 | |
Jens Axboe | 03ba378 | 2009-09-09 09:08:54 +0200 | [diff] [blame] | 868 | expired = wb->last_old_flush + |
| 869 | msecs_to_jiffies(dirty_writeback_interval * 10); |
| 870 | if (time_before(jiffies, expired)) |
| 871 | return 0; |
| 872 | |
| 873 | wb->last_old_flush = jiffies; |
| 874 | nr_pages = global_page_state(NR_FILE_DIRTY) + |
| 875 | global_page_state(NR_UNSTABLE_NFS) + |
| 876 | (inodes_stat.nr_inodes - inodes_stat.nr_unused); |
| 877 | |
Jens Axboe | c4a77a6 | 2009-09-16 15:18:25 +0200 | [diff] [blame] | 878 | if (nr_pages) { |
| 879 | struct wb_writeback_args args = { |
| 880 | .nr_pages = nr_pages, |
| 881 | .sync_mode = WB_SYNC_NONE, |
| 882 | .for_kupdate = 1, |
| 883 | .range_cyclic = 1, |
| 884 | }; |
| 885 | |
| 886 | return wb_writeback(wb, &args); |
| 887 | } |
Jens Axboe | 03ba378 | 2009-09-09 09:08:54 +0200 | [diff] [blame] | 888 | |
| 889 | return 0; |
| 890 | } |
| 891 | |
| 892 | /* |
| 893 | * Retrieve work items and do the writeback they describe |
| 894 | */ |
| 895 | long wb_do_writeback(struct bdi_writeback *wb, int force_wait) |
| 896 | { |
| 897 | struct backing_dev_info *bdi = wb->bdi; |
| 898 | struct bdi_work *work; |
Jens Axboe | c4a77a6 | 2009-09-16 15:18:25 +0200 | [diff] [blame] | 899 | long wrote = 0; |
Jens Axboe | 03ba378 | 2009-09-09 09:08:54 +0200 | [diff] [blame] | 900 | |
| 901 | while ((work = get_next_work_item(bdi, wb)) != NULL) { |
Jens Axboe | c4a77a6 | 2009-09-16 15:18:25 +0200 | [diff] [blame] | 902 | struct wb_writeback_args args = work->args; |
Jens Axboe | 03ba378 | 2009-09-09 09:08:54 +0200 | [diff] [blame] | 903 | |
| 904 | /* |
| 905 | * Override sync mode, in case we must wait for completion |
| 906 | */ |
| 907 | if (force_wait) |
Jens Axboe | c4a77a6 | 2009-09-16 15:18:25 +0200 | [diff] [blame] | 908 | work->args.sync_mode = args.sync_mode = WB_SYNC_ALL; |
Jens Axboe | 03ba378 | 2009-09-09 09:08:54 +0200 | [diff] [blame] | 909 | |
| 910 | /* |
| 911 | * If this isn't a data integrity operation, just notify |
| 912 | * that we have seen this work and we are now starting it. |
| 913 | */ |
Jens Axboe | f17625b | 2010-06-01 11:05:22 +0200 | [diff] [blame] | 914 | if (args.sync_mode == WB_SYNC_NONE) |
Jens Axboe | 03ba378 | 2009-09-09 09:08:54 +0200 | [diff] [blame] | 915 | wb_clear_pending(wb, work); |
| 916 | |
Jens Axboe | c4a77a6 | 2009-09-16 15:18:25 +0200 | [diff] [blame] | 917 | wrote += wb_writeback(wb, &args); |
Jens Axboe | 03ba378 | 2009-09-09 09:08:54 +0200 | [diff] [blame] | 918 | |
| 919 | /* |
| 920 | * This is a data integrity writeback, so only do the |
| 921 | * notification when we have completed the work. |
| 922 | */ |
Jens Axboe | f17625b | 2010-06-01 11:05:22 +0200 | [diff] [blame] | 923 | if (args.sync_mode == WB_SYNC_ALL) |
Jens Axboe | 03ba378 | 2009-09-09 09:08:54 +0200 | [diff] [blame] | 924 | wb_clear_pending(wb, work); |
| 925 | } |
| 926 | |
| 927 | /* |
| 928 | * Check for periodic writeback, kupdated() style |
| 929 | */ |
| 930 | wrote += wb_check_old_data_flush(wb); |
| 931 | |
| 932 | return wrote; |
| 933 | } |
| 934 | |
| 935 | /* |
| 936 | * Handle writeback of dirty data for the device backed by this bdi. Also |
| 937 | * wakes up periodically and does kupdated style flushing. |
| 938 | */ |
| 939 | int bdi_writeback_task(struct bdi_writeback *wb) |
| 940 | { |
| 941 | unsigned long last_active = jiffies; |
| 942 | unsigned long wait_jiffies = -1UL; |
| 943 | long pages_written; |
| 944 | |
| 945 | while (!kthread_should_stop()) { |
| 946 | pages_written = wb_do_writeback(wb, 0); |
| 947 | |
| 948 | if (pages_written) |
| 949 | last_active = jiffies; |
| 950 | else if (wait_jiffies != -1UL) { |
| 951 | unsigned long max_idle; |
| 952 | |
| 953 | /* |
| 954 | * Longest period of inactivity that we tolerate. If we |
| 955 | * see dirty data again later, the task will get |
| 956 | * recreated automatically. |
| 957 | */ |
| 958 | max_idle = max(5UL * 60 * HZ, wait_jiffies); |
| 959 | if (time_after(jiffies, max_idle + last_active)) |
| 960 | break; |
| 961 | } |
| 962 | |
Jens Axboe | 69b62d0 | 2010-05-17 12:51:03 +0200 | [diff] [blame] | 963 | if (dirty_writeback_interval) { |
| 964 | wait_jiffies = msecs_to_jiffies(dirty_writeback_interval * 10); |
| 965 | schedule_timeout_interruptible(wait_jiffies); |
Jens Axboe | f9eadbb | 2010-05-18 14:31:45 +0200 | [diff] [blame] | 966 | } else { |
| 967 | set_current_state(TASK_INTERRUPTIBLE); |
| 968 | if (list_empty_careful(&wb->bdi->work_list) && |
| 969 | !kthread_should_stop()) |
| 970 | schedule(); |
| 971 | __set_current_state(TASK_RUNNING); |
| 972 | } |
Jens Axboe | 69b62d0 | 2010-05-17 12:51:03 +0200 | [diff] [blame] | 973 | |
Jens Axboe | 03ba378 | 2009-09-09 09:08:54 +0200 | [diff] [blame] | 974 | try_to_freeze(); |
| 975 | } |
| 976 | |
| 977 | return 0; |
| 978 | } |
| 979 | |
| 980 | /* |
Jens Axboe | b6e5131 | 2009-09-16 15:13:54 +0200 | [diff] [blame] | 981 | * Schedule writeback for all backing devices. This does WB_SYNC_NONE |
| 982 | * writeback, for integrity writeback see bdi_sync_writeback(). |
Jens Axboe | 03ba378 | 2009-09-09 09:08:54 +0200 | [diff] [blame] | 983 | */ |
Jens Axboe | b6e5131 | 2009-09-16 15:13:54 +0200 | [diff] [blame] | 984 | static void bdi_writeback_all(struct super_block *sb, long nr_pages) |
Jens Axboe | 03ba378 | 2009-09-09 09:08:54 +0200 | [diff] [blame] | 985 | { |
Jens Axboe | b6e5131 | 2009-09-16 15:13:54 +0200 | [diff] [blame] | 986 | struct wb_writeback_args args = { |
| 987 | .sb = sb, |
| 988 | .nr_pages = nr_pages, |
| 989 | .sync_mode = WB_SYNC_NONE, |
| 990 | }; |
Jens Axboe | 03ba378 | 2009-09-09 09:08:54 +0200 | [diff] [blame] | 991 | struct backing_dev_info *bdi; |
Jens Axboe | 03ba378 | 2009-09-09 09:08:54 +0200 | [diff] [blame] | 992 | |
Jens Axboe | cfc4ba5 | 2009-09-14 13:12:40 +0200 | [diff] [blame] | 993 | rcu_read_lock(); |
Jens Axboe | 03ba378 | 2009-09-09 09:08:54 +0200 | [diff] [blame] | 994 | |
Jens Axboe | cfc4ba5 | 2009-09-14 13:12:40 +0200 | [diff] [blame] | 995 | list_for_each_entry_rcu(bdi, &bdi_list, bdi_list) { |
Jens Axboe | 03ba378 | 2009-09-09 09:08:54 +0200 | [diff] [blame] | 996 | if (!bdi_has_dirty_io(bdi)) |
| 997 | continue; |
| 998 | |
Jens Axboe | f17625b | 2010-06-01 11:05:22 +0200 | [diff] [blame] | 999 | bdi_alloc_queue_work(bdi, &args); |
Jens Axboe | 03ba378 | 2009-09-09 09:08:54 +0200 | [diff] [blame] | 1000 | } |
| 1001 | |
Jens Axboe | cfc4ba5 | 2009-09-14 13:12:40 +0200 | [diff] [blame] | 1002 | rcu_read_unlock(); |
Jens Axboe | 03ba378 | 2009-09-09 09:08:54 +0200 | [diff] [blame] | 1003 | } |
| 1004 | |
| 1005 | /* |
| 1006 | * Start writeback of `nr_pages' pages. If `nr_pages' is zero, write back |
| 1007 | * the whole world. |
| 1008 | */ |
| 1009 | void wakeup_flusher_threads(long nr_pages) |
| 1010 | { |
Jens Axboe | 03ba378 | 2009-09-09 09:08:54 +0200 | [diff] [blame] | 1011 | if (nr_pages == 0) |
| 1012 | nr_pages = global_page_state(NR_FILE_DIRTY) + |
| 1013 | global_page_state(NR_UNSTABLE_NFS); |
Jens Axboe | b6e5131 | 2009-09-16 15:13:54 +0200 | [diff] [blame] | 1014 | bdi_writeback_all(NULL, nr_pages); |
Jens Axboe | 03ba378 | 2009-09-09 09:08:54 +0200 | [diff] [blame] | 1015 | } |
| 1016 | |
| 1017 | static noinline void block_dump___mark_inode_dirty(struct inode *inode) |
| 1018 | { |
| 1019 | if (inode->i_ino || strcmp(inode->i_sb->s_id, "bdev")) { |
| 1020 | struct dentry *dentry; |
| 1021 | const char *name = "?"; |
| 1022 | |
| 1023 | dentry = d_find_alias(inode); |
| 1024 | if (dentry) { |
| 1025 | spin_lock(&dentry->d_lock); |
| 1026 | name = (const char *) dentry->d_name.name; |
| 1027 | } |
| 1028 | printk(KERN_DEBUG |
| 1029 | "%s(%d): dirtied inode %lu (%s) on %s\n", |
| 1030 | current->comm, task_pid_nr(current), inode->i_ino, |
| 1031 | name, inode->i_sb->s_id); |
| 1032 | if (dentry) { |
| 1033 | spin_unlock(&dentry->d_lock); |
| 1034 | dput(dentry); |
| 1035 | } |
| 1036 | } |
| 1037 | } |
| 1038 | |
| 1039 | /** |
| 1040 | * __mark_inode_dirty - internal function |
| 1041 | * @inode: inode to mark |
| 1042 | * @flags: what kind of dirty (i.e. I_DIRTY_SYNC) |
| 1043 | * Mark an inode as dirty. Callers should use mark_inode_dirty or |
| 1044 | * mark_inode_dirty_sync. |
| 1045 | * |
| 1046 | * Put the inode on the super block's dirty list. |
| 1047 | * |
| 1048 | * CAREFUL! We mark it dirty unconditionally, but move it onto the |
| 1049 | * dirty list only if it is hashed or if it refers to a blockdev. |
| 1050 | * If it was not hashed, it will never be added to the dirty list |
| 1051 | * even if it is later hashed, as it will have been marked dirty already. |
| 1052 | * |
| 1053 | * In short, make sure you hash any inodes _before_ you start marking |
| 1054 | * them dirty. |
| 1055 | * |
| 1056 | * This function *must* be atomic for the I_DIRTY_PAGES case - |
| 1057 | * set_page_dirty() is called under spinlock in several places. |
| 1058 | * |
| 1059 | * Note that for blockdevs, inode->dirtied_when represents the dirtying time of |
| 1060 | * the block-special inode (/dev/hda1) itself. And the ->dirtied_when field of |
| 1061 | * the kernel-internal blockdev inode represents the dirtying time of the |
| 1062 | * blockdev's pages. This is why for I_DIRTY_PAGES we always use |
| 1063 | * page->mapping->host, so the page-dirtying time is recorded in the internal |
| 1064 | * blockdev inode. |
| 1065 | */ |
| 1066 | void __mark_inode_dirty(struct inode *inode, int flags) |
| 1067 | { |
| 1068 | struct super_block *sb = inode->i_sb; |
| 1069 | |
| 1070 | /* |
| 1071 | * Don't do this for I_DIRTY_PAGES - that doesn't actually |
| 1072 | * dirty the inode itself |
| 1073 | */ |
| 1074 | if (flags & (I_DIRTY_SYNC | I_DIRTY_DATASYNC)) { |
| 1075 | if (sb->s_op->dirty_inode) |
| 1076 | sb->s_op->dirty_inode(inode); |
| 1077 | } |
| 1078 | |
| 1079 | /* |
| 1080 | * make sure that changes are seen by all cpus before we test i_state |
| 1081 | * -- mikulas |
| 1082 | */ |
| 1083 | smp_mb(); |
| 1084 | |
| 1085 | /* avoid the locking if we can */ |
| 1086 | if ((inode->i_state & flags) == flags) |
| 1087 | return; |
| 1088 | |
| 1089 | if (unlikely(block_dump)) |
| 1090 | block_dump___mark_inode_dirty(inode); |
| 1091 | |
| 1092 | spin_lock(&inode_lock); |
| 1093 | if ((inode->i_state & flags) != flags) { |
| 1094 | const int was_dirty = inode->i_state & I_DIRTY; |
| 1095 | |
| 1096 | inode->i_state |= flags; |
| 1097 | |
| 1098 | /* |
| 1099 | * If the inode is being synced, just update its dirty state. |
| 1100 | * The unlocker will place the inode on the appropriate |
| 1101 | * superblock list, based upon its state. |
| 1102 | */ |
| 1103 | if (inode->i_state & I_SYNC) |
| 1104 | goto out; |
| 1105 | |
| 1106 | /* |
| 1107 | * Only add valid (hashed) inodes to the superblock's |
| 1108 | * dirty list. Add blockdev inodes as well. |
| 1109 | */ |
| 1110 | if (!S_ISBLK(inode->i_mode)) { |
| 1111 | if (hlist_unhashed(&inode->i_hash)) |
| 1112 | goto out; |
| 1113 | } |
| 1114 | if (inode->i_state & (I_FREEING|I_CLEAR)) |
| 1115 | goto out; |
| 1116 | |
| 1117 | /* |
| 1118 | * If the inode was already on b_dirty/b_io/b_more_io, don't |
| 1119 | * reposition it (that would break b_dirty time-ordering). |
| 1120 | */ |
| 1121 | if (!was_dirty) { |
| 1122 | struct bdi_writeback *wb = &inode_to_bdi(inode)->wb; |
Jens Axboe | 500b067 | 2009-09-09 09:10:25 +0200 | [diff] [blame] | 1123 | struct backing_dev_info *bdi = wb->bdi; |
| 1124 | |
| 1125 | if (bdi_cap_writeback_dirty(bdi) && |
| 1126 | !test_bit(BDI_registered, &bdi->state)) { |
| 1127 | WARN_ON(1); |
| 1128 | printk(KERN_ERR "bdi-%s not registered\n", |
| 1129 | bdi->name); |
| 1130 | } |
Jens Axboe | 03ba378 | 2009-09-09 09:08:54 +0200 | [diff] [blame] | 1131 | |
| 1132 | inode->dirtied_when = jiffies; |
| 1133 | list_move(&inode->i_list, &wb->b_dirty); |
| 1134 | } |
| 1135 | } |
| 1136 | out: |
| 1137 | spin_unlock(&inode_lock); |
| 1138 | } |
| 1139 | EXPORT_SYMBOL(__mark_inode_dirty); |
| 1140 | |
Jens Axboe | 66f3b8e | 2009-09-02 09:19:46 +0200 | [diff] [blame] | 1141 | /* |
| 1142 | * Write out a superblock's list of dirty inodes. A wait will be performed |
| 1143 | * upon no inodes, all inodes or the final one, depending upon sync_mode. |
| 1144 | * |
| 1145 | * If older_than_this is non-NULL, then only write out inodes which |
| 1146 | * had their first dirtying at a time earlier than *older_than_this. |
| 1147 | * |
Jens Axboe | 66f3b8e | 2009-09-02 09:19:46 +0200 | [diff] [blame] | 1148 | * If `bdi' is non-zero then we're being asked to writeback a specific queue. |
| 1149 | * This function assumes that the blockdev superblock's inodes are backed by |
| 1150 | * a variety of queues, so all inodes are searched. For other superblocks, |
| 1151 | * assume that all inodes are backed by the same queue. |
| 1152 | * |
Jens Axboe | 66f3b8e | 2009-09-02 09:19:46 +0200 | [diff] [blame] | 1153 | * The inodes to be written are parked on bdi->b_io. They are moved back onto |
| 1154 | * bdi->b_dirty as they are selected for writing. This way, none can be missed |
| 1155 | * on the writer throttling path, and we get decent balancing between many |
| 1156 | * throttled threads: we don't want them all piling up on inode_sync_wait. |
| 1157 | */ |
Jens Axboe | b6e5131 | 2009-09-16 15:13:54 +0200 | [diff] [blame] | 1158 | static void wait_sb_inodes(struct super_block *sb) |
Jens Axboe | 66f3b8e | 2009-09-02 09:19:46 +0200 | [diff] [blame] | 1159 | { |
Jens Axboe | 03ba378 | 2009-09-09 09:08:54 +0200 | [diff] [blame] | 1160 | struct inode *inode, *old_inode = NULL; |
Jens Axboe | 66f3b8e | 2009-09-02 09:19:46 +0200 | [diff] [blame] | 1161 | |
Jens Axboe | 03ba378 | 2009-09-09 09:08:54 +0200 | [diff] [blame] | 1162 | /* |
| 1163 | * We need to be protected against the filesystem going from |
| 1164 | * r/o to r/w or vice versa. |
| 1165 | */ |
Jens Axboe | b6e5131 | 2009-09-16 15:13:54 +0200 | [diff] [blame] | 1166 | WARN_ON(!rwsem_is_locked(&sb->s_umount)); |
Jens Axboe | 66f3b8e | 2009-09-02 09:19:46 +0200 | [diff] [blame] | 1167 | |
Jens Axboe | 03ba378 | 2009-09-09 09:08:54 +0200 | [diff] [blame] | 1168 | spin_lock(&inode_lock); |
| 1169 | |
| 1170 | /* |
| 1171 | * Data integrity sync. Must wait for all pages under writeback, |
| 1172 | * because there may have been pages dirtied before our sync |
| 1173 | * call, but which had writeout started before we write it out. |
| 1174 | * In which case, the inode may not be on the dirty list, but |
| 1175 | * we still have to wait for that writeout. |
| 1176 | */ |
Jens Axboe | b6e5131 | 2009-09-16 15:13:54 +0200 | [diff] [blame] | 1177 | list_for_each_entry(inode, &sb->s_inodes, i_sb_list) { |
Jens Axboe | 03ba378 | 2009-09-09 09:08:54 +0200 | [diff] [blame] | 1178 | struct address_space *mapping; |
| 1179 | |
| 1180 | if (inode->i_state & (I_FREEING|I_CLEAR|I_WILL_FREE|I_NEW)) |
| 1181 | continue; |
| 1182 | mapping = inode->i_mapping; |
| 1183 | if (mapping->nrpages == 0) |
| 1184 | continue; |
| 1185 | __iget(inode); |
| 1186 | spin_unlock(&inode_lock); |
| 1187 | /* |
| 1188 | * We hold a reference to 'inode' so it couldn't have |
| 1189 | * been removed from s_inodes list while we dropped the |
| 1190 | * inode_lock. We cannot iput the inode now as we can |
| 1191 | * be holding the last reference and we cannot iput it |
| 1192 | * under inode_lock. So we keep the reference and iput |
| 1193 | * it later. |
| 1194 | */ |
| 1195 | iput(old_inode); |
| 1196 | old_inode = inode; |
| 1197 | |
| 1198 | filemap_fdatawait(mapping); |
| 1199 | |
| 1200 | cond_resched(); |
Nick Piggin | 38f2197 | 2009-01-06 14:40:25 -0800 | [diff] [blame] | 1201 | |
Jens Axboe | 66f3b8e | 2009-09-02 09:19:46 +0200 | [diff] [blame] | 1202 | spin_lock(&inode_lock); |
Jens Axboe | 66f3b8e | 2009-09-02 09:19:46 +0200 | [diff] [blame] | 1203 | } |
Jens Axboe | 03ba378 | 2009-09-09 09:08:54 +0200 | [diff] [blame] | 1204 | spin_unlock(&inode_lock); |
| 1205 | iput(old_inode); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1206 | } |
| 1207 | |
Jens Axboe | d8a8559 | 2009-09-02 12:34:32 +0200 | [diff] [blame] | 1208 | /** |
| 1209 | * writeback_inodes_sb - writeback dirty inodes from given super_block |
| 1210 | * @sb: the superblock |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1211 | * |
Jens Axboe | d8a8559 | 2009-09-02 12:34:32 +0200 | [diff] [blame] | 1212 | * Start writeback on some inodes on this super_block. No guarantees are made |
| 1213 | * on how many (if any) will be written, and this function does not wait |
| 1214 | * for IO completion of submitted IO. The number of pages submitted is |
| 1215 | * returned. |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1216 | */ |
Jens Axboe | b6e5131 | 2009-09-16 15:13:54 +0200 | [diff] [blame] | 1217 | void writeback_inodes_sb(struct super_block *sb) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1218 | { |
Jens Axboe | 0e3c9a2 | 2010-06-01 11:08:43 +0200 | [diff] [blame^] | 1219 | unsigned long nr_dirty = global_page_state(NR_FILE_DIRTY); |
| 1220 | unsigned long nr_unstable = global_page_state(NR_UNSTABLE_NFS); |
| 1221 | long nr_to_write; |
| 1222 | |
| 1223 | nr_to_write = nr_dirty + nr_unstable + |
| 1224 | (inodes_stat.nr_inodes - inodes_stat.nr_unused); |
| 1225 | |
| 1226 | bdi_start_writeback(sb->s_bdi, sb, nr_to_write); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1227 | } |
Jens Axboe | d8a8559 | 2009-09-02 12:34:32 +0200 | [diff] [blame] | 1228 | EXPORT_SYMBOL(writeback_inodes_sb); |
| 1229 | |
| 1230 | /** |
Eric Sandeen | 17bd55d | 2009-12-23 07:57:07 -0500 | [diff] [blame] | 1231 | * writeback_inodes_sb_if_idle - start writeback if none underway |
| 1232 | * @sb: the superblock |
| 1233 | * |
| 1234 | * Invoke writeback_inodes_sb if no writeback is currently underway. |
| 1235 | * Returns 1 if writeback was started, 0 if not. |
| 1236 | */ |
| 1237 | int writeback_inodes_sb_if_idle(struct super_block *sb) |
| 1238 | { |
| 1239 | if (!writeback_in_progress(sb->s_bdi)) { |
| 1240 | writeback_inodes_sb(sb); |
| 1241 | return 1; |
| 1242 | } else |
| 1243 | return 0; |
| 1244 | } |
| 1245 | EXPORT_SYMBOL(writeback_inodes_sb_if_idle); |
| 1246 | |
| 1247 | /** |
Jens Axboe | d8a8559 | 2009-09-02 12:34:32 +0200 | [diff] [blame] | 1248 | * sync_inodes_sb - sync sb inode pages |
| 1249 | * @sb: the superblock |
| 1250 | * |
| 1251 | * This function writes and waits on any dirty inode belonging to this |
| 1252 | * super_block. The number of pages synced is returned. |
| 1253 | */ |
Jens Axboe | b6e5131 | 2009-09-16 15:13:54 +0200 | [diff] [blame] | 1254 | void sync_inodes_sb(struct super_block *sb) |
Jens Axboe | d8a8559 | 2009-09-02 12:34:32 +0200 | [diff] [blame] | 1255 | { |
Jens Axboe | b6e5131 | 2009-09-16 15:13:54 +0200 | [diff] [blame] | 1256 | bdi_sync_writeback(sb->s_bdi, sb); |
| 1257 | wait_sb_inodes(sb); |
Jens Axboe | d8a8559 | 2009-09-02 12:34:32 +0200 | [diff] [blame] | 1258 | } |
| 1259 | EXPORT_SYMBOL(sync_inodes_sb); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1260 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1261 | /** |
Andrea Arcangeli | 7f04c26 | 2005-10-30 15:03:05 -0800 | [diff] [blame] | 1262 | * write_inode_now - write an inode to disk |
| 1263 | * @inode: inode to write to disk |
| 1264 | * @sync: whether the write should be synchronous or not |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1265 | * |
Andrea Arcangeli | 7f04c26 | 2005-10-30 15:03:05 -0800 | [diff] [blame] | 1266 | * This function commits an inode to disk immediately if it is dirty. This is |
| 1267 | * primarily needed by knfsd. |
| 1268 | * |
| 1269 | * 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] | 1270 | */ |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1271 | int write_inode_now(struct inode *inode, int sync) |
| 1272 | { |
| 1273 | int ret; |
| 1274 | struct writeback_control wbc = { |
| 1275 | .nr_to_write = LONG_MAX, |
Mike Galbraith | 18914b1 | 2008-02-08 04:20:23 -0800 | [diff] [blame] | 1276 | .sync_mode = sync ? WB_SYNC_ALL : WB_SYNC_NONE, |
OGAWA Hirofumi | 111ebb6 | 2006-06-23 02:03:26 -0700 | [diff] [blame] | 1277 | .range_start = 0, |
| 1278 | .range_end = LLONG_MAX, |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1279 | }; |
| 1280 | |
| 1281 | if (!mapping_cap_writeback_dirty(inode->i_mapping)) |
Andrew Morton | 49364ce | 2005-11-07 00:59:15 -0800 | [diff] [blame] | 1282 | wbc.nr_to_write = 0; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1283 | |
| 1284 | might_sleep(); |
| 1285 | spin_lock(&inode_lock); |
Christoph Hellwig | 01c0319 | 2009-06-08 13:35:40 +0200 | [diff] [blame] | 1286 | ret = writeback_single_inode(inode, &wbc); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1287 | spin_unlock(&inode_lock); |
| 1288 | if (sync) |
Joern Engel | 1c0eeaf | 2007-10-16 23:30:44 -0700 | [diff] [blame] | 1289 | inode_sync_wait(inode); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1290 | return ret; |
| 1291 | } |
| 1292 | EXPORT_SYMBOL(write_inode_now); |
| 1293 | |
| 1294 | /** |
| 1295 | * sync_inode - write an inode and its pages to disk. |
| 1296 | * @inode: the inode to sync |
| 1297 | * @wbc: controls the writeback mode |
| 1298 | * |
| 1299 | * sync_inode() will write an inode and its pages to disk. It will also |
| 1300 | * correctly update the inode on its superblock's dirty inode lists and will |
| 1301 | * update inode->i_state. |
| 1302 | * |
| 1303 | * The caller must have a ref on the inode. |
| 1304 | */ |
| 1305 | int sync_inode(struct inode *inode, struct writeback_control *wbc) |
| 1306 | { |
| 1307 | int ret; |
| 1308 | |
| 1309 | spin_lock(&inode_lock); |
Christoph Hellwig | 01c0319 | 2009-06-08 13:35:40 +0200 | [diff] [blame] | 1310 | ret = writeback_single_inode(inode, wbc); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1311 | spin_unlock(&inode_lock); |
| 1312 | return ret; |
| 1313 | } |
| 1314 | EXPORT_SYMBOL(sync_inode); |