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> |
Paul Gortmaker | 630d9c4 | 2011-11-16 23:57:37 -0500 | [diff] [blame] | 17 | #include <linux/export.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> |
Wu Fengguang | bc31b86 | 2012-01-07 20:41:55 -0600 | [diff] [blame] | 23 | #include <linux/pagemap.h> |
Jens Axboe | 03ba378 | 2009-09-09 09:08:54 +0200 | [diff] [blame] | 24 | #include <linux/kthread.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> |
Dave Chinner | 455b286 | 2010-07-07 13:24:06 +1000 | [diff] [blame] | 28 | #include <linux/tracepoint.h> |
Al Viro | 719ea2f | 2013-09-29 11:24:49 -0400 | [diff] [blame] | 29 | #include <linux/device.h> |
Tejun Heo | 21c6321 | 2015-05-28 14:50:49 -0400 | [diff] [blame] | 30 | #include <linux/memcontrol.h> |
David Howells | 07f3f05c | 2006-09-30 20:52:18 +0200 | [diff] [blame] | 31 | #include "internal.h" |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 32 | |
Jens Axboe | d0bceac | 2009-05-18 08:20:32 +0200 | [diff] [blame] | 33 | /* |
Wu Fengguang | bc31b86 | 2012-01-07 20:41:55 -0600 | [diff] [blame] | 34 | * 4MB minimal write chunk size |
| 35 | */ |
| 36 | #define MIN_WRITEBACK_PAGES (4096UL >> (PAGE_CACHE_SHIFT - 10)) |
| 37 | |
Tejun Heo | cc395d7 | 2015-05-22 17:13:58 -0400 | [diff] [blame] | 38 | struct wb_completion { |
| 39 | atomic_t cnt; |
| 40 | }; |
| 41 | |
Wu Fengguang | bc31b86 | 2012-01-07 20:41:55 -0600 | [diff] [blame] | 42 | /* |
Jens Axboe | c4a77a6 | 2009-09-16 15:18:25 +0200 | [diff] [blame] | 43 | * Passed into wb_writeback(), essentially a subset of writeback_control |
| 44 | */ |
Christoph Hellwig | 83ba7b0 | 2010-07-06 08:59:53 +0200 | [diff] [blame] | 45 | struct wb_writeback_work { |
Jens Axboe | c4a77a6 | 2009-09-16 15:18:25 +0200 | [diff] [blame] | 46 | long nr_pages; |
| 47 | struct super_block *sb; |
Jan Kara | 0dc83bd | 2014-02-21 11:19:04 +0100 | [diff] [blame] | 48 | unsigned long *older_than_this; |
Jens Axboe | c4a77a6 | 2009-09-16 15:18:25 +0200 | [diff] [blame] | 49 | enum writeback_sync_modes sync_mode; |
Wu Fengguang | 6e6938b | 2010-06-06 10:38:15 -0600 | [diff] [blame] | 50 | unsigned int tagged_writepages:1; |
H Hartley Sweeten | 52957fe | 2010-04-01 20:36:30 -0500 | [diff] [blame] | 51 | unsigned int for_kupdate:1; |
| 52 | unsigned int range_cyclic:1; |
| 53 | unsigned int for_background:1; |
Dave Chinner | 7747bd4 | 2013-07-02 22:38:35 +1000 | [diff] [blame] | 54 | unsigned int for_sync:1; /* sync(2) WB_SYNC_ALL writeback */ |
Tejun Heo | ac7b19a | 2015-05-22 17:13:57 -0400 | [diff] [blame] | 55 | unsigned int auto_free:1; /* free on completion */ |
Curt Wohlgemuth | 0e175a1 | 2011-10-07 21:54:10 -0600 | [diff] [blame] | 56 | enum wb_reason reason; /* why was writeback initiated? */ |
Jens Axboe | c4a77a6 | 2009-09-16 15:18:25 +0200 | [diff] [blame] | 57 | |
Jens Axboe | 8010c3b | 2009-09-15 20:04:57 +0200 | [diff] [blame] | 58 | struct list_head list; /* pending work list */ |
Tejun Heo | cc395d7 | 2015-05-22 17:13:58 -0400 | [diff] [blame] | 59 | struct wb_completion *done; /* set if the caller waits */ |
Jens Axboe | 03ba378 | 2009-09-09 09:08:54 +0200 | [diff] [blame] | 60 | }; |
| 61 | |
Theodore Ts'o | a2f4870 | 2015-03-17 12:23:19 -0400 | [diff] [blame] | 62 | /* |
Tejun Heo | cc395d7 | 2015-05-22 17:13:58 -0400 | [diff] [blame] | 63 | * If one wants to wait for one or more wb_writeback_works, each work's |
| 64 | * ->done should be set to a wb_completion defined using the following |
| 65 | * macro. Once all work items are issued with wb_queue_work(), the caller |
| 66 | * can wait for the completion of all using wb_wait_for_completion(). Work |
| 67 | * items which are waited upon aren't freed automatically on completion. |
| 68 | */ |
| 69 | #define DEFINE_WB_COMPLETION_ONSTACK(cmpl) \ |
| 70 | struct wb_completion cmpl = { \ |
| 71 | .cnt = ATOMIC_INIT(1), \ |
| 72 | } |
| 73 | |
| 74 | |
| 75 | /* |
Theodore Ts'o | a2f4870 | 2015-03-17 12:23:19 -0400 | [diff] [blame] | 76 | * If an inode is constantly having its pages dirtied, but then the |
| 77 | * updates stop dirtytime_expire_interval seconds in the past, it's |
| 78 | * possible for the worst case time between when an inode has its |
| 79 | * timestamps updated and when they finally get written out to be two |
| 80 | * dirtytime_expire_intervals. We set the default to 12 hours (in |
| 81 | * seconds), which means most of the time inodes will have their |
| 82 | * timestamps written to disk after 12 hours, but in the worst case a |
| 83 | * few inodes might not their timestamps updated for 24 hours. |
| 84 | */ |
| 85 | unsigned int dirtytime_expire_interval = 12 * 60 * 60; |
| 86 | |
Nick Piggin | 7ccf19a | 2010-10-21 11:49:30 +1100 | [diff] [blame] | 87 | static inline struct inode *wb_inode(struct list_head *head) |
| 88 | { |
Dave Chinner | c7f5408 | 2015-03-04 14:07:22 -0500 | [diff] [blame] | 89 | return list_entry(head, struct inode, i_io_list); |
Nick Piggin | 7ccf19a | 2010-10-21 11:49:30 +1100 | [diff] [blame] | 90 | } |
| 91 | |
Wu Fengguang | 15eb77a | 2012-01-17 11:18:56 -0600 | [diff] [blame] | 92 | /* |
| 93 | * Include the creation of the trace points after defining the |
| 94 | * wb_writeback_work structure and inline functions so that the definition |
| 95 | * remains local to this file. |
| 96 | */ |
| 97 | #define CREATE_TRACE_POINTS |
| 98 | #include <trace/events/writeback.h> |
| 99 | |
Steven Whitehouse | 774016b | 2014-02-06 15:47:47 +0000 | [diff] [blame] | 100 | EXPORT_TRACEPOINT_SYMBOL_GPL(wbc_writepage); |
| 101 | |
Tejun Heo | d6c10f1 | 2015-05-22 17:13:45 -0400 | [diff] [blame] | 102 | static bool wb_io_lists_populated(struct bdi_writeback *wb) |
| 103 | { |
| 104 | if (wb_has_dirty_io(wb)) { |
| 105 | return false; |
| 106 | } else { |
| 107 | set_bit(WB_has_dirty_io, &wb->state); |
Tejun Heo | 95a46c6 | 2015-05-22 17:13:47 -0400 | [diff] [blame] | 108 | WARN_ON_ONCE(!wb->avg_write_bandwidth); |
Tejun Heo | 766a9d6 | 2015-05-22 17:13:46 -0400 | [diff] [blame] | 109 | atomic_long_add(wb->avg_write_bandwidth, |
| 110 | &wb->bdi->tot_write_bandwidth); |
Tejun Heo | d6c10f1 | 2015-05-22 17:13:45 -0400 | [diff] [blame] | 111 | return true; |
| 112 | } |
| 113 | } |
| 114 | |
| 115 | static void wb_io_lists_depopulated(struct bdi_writeback *wb) |
| 116 | { |
| 117 | if (wb_has_dirty_io(wb) && list_empty(&wb->b_dirty) && |
Tejun Heo | 766a9d6 | 2015-05-22 17:13:46 -0400 | [diff] [blame] | 118 | list_empty(&wb->b_io) && list_empty(&wb->b_more_io)) { |
Tejun Heo | d6c10f1 | 2015-05-22 17:13:45 -0400 | [diff] [blame] | 119 | clear_bit(WB_has_dirty_io, &wb->state); |
Tejun Heo | 95a46c6 | 2015-05-22 17:13:47 -0400 | [diff] [blame] | 120 | WARN_ON_ONCE(atomic_long_sub_return(wb->avg_write_bandwidth, |
| 121 | &wb->bdi->tot_write_bandwidth) < 0); |
Tejun Heo | 766a9d6 | 2015-05-22 17:13:46 -0400 | [diff] [blame] | 122 | } |
Tejun Heo | d6c10f1 | 2015-05-22 17:13:45 -0400 | [diff] [blame] | 123 | } |
| 124 | |
| 125 | /** |
Dave Chinner | c7f5408 | 2015-03-04 14:07:22 -0500 | [diff] [blame] | 126 | * inode_io_list_move_locked - move an inode onto a bdi_writeback IO list |
Tejun Heo | d6c10f1 | 2015-05-22 17:13:45 -0400 | [diff] [blame] | 127 | * @inode: inode to be moved |
| 128 | * @wb: target bdi_writeback |
| 129 | * @head: one of @wb->b_{dirty|io|more_io} |
| 130 | * |
Dave Chinner | c7f5408 | 2015-03-04 14:07:22 -0500 | [diff] [blame] | 131 | * Move @inode->i_io_list to @list of @wb and set %WB_has_dirty_io. |
Tejun Heo | d6c10f1 | 2015-05-22 17:13:45 -0400 | [diff] [blame] | 132 | * Returns %true if @inode is the first occupant of the !dirty_time IO |
| 133 | * lists; otherwise, %false. |
| 134 | */ |
Dave Chinner | c7f5408 | 2015-03-04 14:07:22 -0500 | [diff] [blame] | 135 | static bool inode_io_list_move_locked(struct inode *inode, |
Tejun Heo | d6c10f1 | 2015-05-22 17:13:45 -0400 | [diff] [blame] | 136 | struct bdi_writeback *wb, |
| 137 | struct list_head *head) |
| 138 | { |
| 139 | assert_spin_locked(&wb->list_lock); |
| 140 | |
Dave Chinner | c7f5408 | 2015-03-04 14:07:22 -0500 | [diff] [blame] | 141 | list_move(&inode->i_io_list, head); |
Tejun Heo | d6c10f1 | 2015-05-22 17:13:45 -0400 | [diff] [blame] | 142 | |
| 143 | /* dirty_time doesn't count as dirty_io until expiration */ |
| 144 | if (head != &wb->b_dirty_time) |
| 145 | return wb_io_lists_populated(wb); |
| 146 | |
| 147 | wb_io_lists_depopulated(wb); |
| 148 | return false; |
| 149 | } |
| 150 | |
| 151 | /** |
Dave Chinner | c7f5408 | 2015-03-04 14:07:22 -0500 | [diff] [blame] | 152 | * inode_io_list_del_locked - remove an inode from its bdi_writeback IO list |
Tejun Heo | d6c10f1 | 2015-05-22 17:13:45 -0400 | [diff] [blame] | 153 | * @inode: inode to be removed |
| 154 | * @wb: bdi_writeback @inode is being removed from |
| 155 | * |
| 156 | * Remove @inode which may be on one of @wb->b_{dirty|io|more_io} lists and |
| 157 | * clear %WB_has_dirty_io if all are empty afterwards. |
| 158 | */ |
Dave Chinner | c7f5408 | 2015-03-04 14:07:22 -0500 | [diff] [blame] | 159 | static void inode_io_list_del_locked(struct inode *inode, |
Tejun Heo | d6c10f1 | 2015-05-22 17:13:45 -0400 | [diff] [blame] | 160 | struct bdi_writeback *wb) |
| 161 | { |
| 162 | assert_spin_locked(&wb->list_lock); |
| 163 | |
Dave Chinner | c7f5408 | 2015-03-04 14:07:22 -0500 | [diff] [blame] | 164 | list_del_init(&inode->i_io_list); |
Tejun Heo | d6c10f1 | 2015-05-22 17:13:45 -0400 | [diff] [blame] | 165 | wb_io_lists_depopulated(wb); |
| 166 | } |
| 167 | |
Tejun Heo | f0054bb | 2015-05-22 17:13:30 -0400 | [diff] [blame] | 168 | static void wb_wakeup(struct bdi_writeback *wb) |
Jan Kara | 5acda9d | 2014-04-03 14:46:23 -0700 | [diff] [blame] | 169 | { |
Tejun Heo | f0054bb | 2015-05-22 17:13:30 -0400 | [diff] [blame] | 170 | spin_lock_bh(&wb->work_lock); |
| 171 | if (test_bit(WB_registered, &wb->state)) |
| 172 | mod_delayed_work(bdi_wq, &wb->dwork, 0); |
| 173 | spin_unlock_bh(&wb->work_lock); |
Jan Kara | 5acda9d | 2014-04-03 14:46:23 -0700 | [diff] [blame] | 174 | } |
| 175 | |
Tejun Heo | f0054bb | 2015-05-22 17:13:30 -0400 | [diff] [blame] | 176 | static void wb_queue_work(struct bdi_writeback *wb, |
| 177 | struct wb_writeback_work *work) |
Jan Kara | 6585027 | 2011-01-13 15:45:44 -0800 | [diff] [blame] | 178 | { |
Tejun Heo | 5634cc2 | 2015-08-18 14:54:56 -0700 | [diff] [blame] | 179 | trace_writeback_queue(wb, work); |
Jan Kara | 6585027 | 2011-01-13 15:45:44 -0800 | [diff] [blame] | 180 | |
Tejun Heo | f0054bb | 2015-05-22 17:13:30 -0400 | [diff] [blame] | 181 | spin_lock_bh(&wb->work_lock); |
Tejun Heo | 8a1270c | 2015-08-18 14:54:53 -0700 | [diff] [blame] | 182 | if (!test_bit(WB_registered, &wb->state)) |
Jan Kara | 5acda9d | 2014-04-03 14:46:23 -0700 | [diff] [blame] | 183 | goto out_unlock; |
Tejun Heo | cc395d7 | 2015-05-22 17:13:58 -0400 | [diff] [blame] | 184 | if (work->done) |
| 185 | atomic_inc(&work->done->cnt); |
Tejun Heo | f0054bb | 2015-05-22 17:13:30 -0400 | [diff] [blame] | 186 | list_add_tail(&work->list, &wb->work_list); |
| 187 | mod_delayed_work(bdi_wq, &wb->dwork, 0); |
Jan Kara | 5acda9d | 2014-04-03 14:46:23 -0700 | [diff] [blame] | 188 | out_unlock: |
Tejun Heo | f0054bb | 2015-05-22 17:13:30 -0400 | [diff] [blame] | 189 | spin_unlock_bh(&wb->work_lock); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 190 | } |
| 191 | |
Tejun Heo | cc395d7 | 2015-05-22 17:13:58 -0400 | [diff] [blame] | 192 | /** |
| 193 | * wb_wait_for_completion - wait for completion of bdi_writeback_works |
| 194 | * @bdi: bdi work items were issued to |
| 195 | * @done: target wb_completion |
| 196 | * |
| 197 | * Wait for one or more work items issued to @bdi with their ->done field |
| 198 | * set to @done, which should have been defined with |
| 199 | * DEFINE_WB_COMPLETION_ONSTACK(). This function returns after all such |
| 200 | * work items are completed. Work items which are waited upon aren't freed |
| 201 | * automatically on completion. |
| 202 | */ |
| 203 | static void wb_wait_for_completion(struct backing_dev_info *bdi, |
| 204 | struct wb_completion *done) |
| 205 | { |
| 206 | atomic_dec(&done->cnt); /* put down the initial count */ |
| 207 | wait_event(bdi->wb_waitq, !atomic_read(&done->cnt)); |
| 208 | } |
| 209 | |
Tejun Heo | 703c270 | 2015-05-22 17:13:44 -0400 | [diff] [blame] | 210 | #ifdef CONFIG_CGROUP_WRITEBACK |
| 211 | |
Tejun Heo | 2a81490 | 2015-05-28 14:50:51 -0400 | [diff] [blame] | 212 | /* parameters for foreign inode detection, see wb_detach_inode() */ |
| 213 | #define WB_FRN_TIME_SHIFT 13 /* 1s = 2^13, upto 8 secs w/ 16bit */ |
| 214 | #define WB_FRN_TIME_AVG_SHIFT 3 /* avg = avg * 7/8 + new * 1/8 */ |
| 215 | #define WB_FRN_TIME_CUT_DIV 2 /* ignore rounds < avg / 2 */ |
| 216 | #define WB_FRN_TIME_PERIOD (2 * (1 << WB_FRN_TIME_SHIFT)) /* 2s */ |
| 217 | |
| 218 | #define WB_FRN_HIST_SLOTS 16 /* inode->i_wb_frn_history is 16bit */ |
| 219 | #define WB_FRN_HIST_UNIT (WB_FRN_TIME_PERIOD / WB_FRN_HIST_SLOTS) |
| 220 | /* each slot's duration is 2s / 16 */ |
| 221 | #define WB_FRN_HIST_THR_SLOTS (WB_FRN_HIST_SLOTS / 2) |
| 222 | /* if foreign slots >= 8, switch */ |
| 223 | #define WB_FRN_HIST_MAX_SLOTS (WB_FRN_HIST_THR_SLOTS / 2 + 1) |
| 224 | /* one round can affect upto 5 slots */ |
| 225 | |
Tejun Heo | 21c6321 | 2015-05-28 14:50:49 -0400 | [diff] [blame] | 226 | void __inode_attach_wb(struct inode *inode, struct page *page) |
| 227 | { |
| 228 | struct backing_dev_info *bdi = inode_to_bdi(inode); |
| 229 | struct bdi_writeback *wb = NULL; |
| 230 | |
| 231 | if (inode_cgwb_enabled(inode)) { |
| 232 | struct cgroup_subsys_state *memcg_css; |
| 233 | |
| 234 | if (page) { |
| 235 | memcg_css = mem_cgroup_css_from_page(page); |
| 236 | wb = wb_get_create(bdi, memcg_css, GFP_ATOMIC); |
| 237 | } else { |
| 238 | /* must pin memcg_css, see wb_get_create() */ |
| 239 | memcg_css = task_get_css(current, memory_cgrp_id); |
| 240 | wb = wb_get_create(bdi, memcg_css, GFP_ATOMIC); |
| 241 | css_put(memcg_css); |
| 242 | } |
| 243 | } |
| 244 | |
| 245 | if (!wb) |
| 246 | wb = &bdi->wb; |
| 247 | |
| 248 | /* |
| 249 | * There may be multiple instances of this function racing to |
| 250 | * update the same inode. Use cmpxchg() to tell the winner. |
| 251 | */ |
| 252 | if (unlikely(cmpxchg(&inode->i_wb, NULL, wb))) |
| 253 | wb_put(wb); |
| 254 | } |
| 255 | |
Tejun Heo | 703c270 | 2015-05-22 17:13:44 -0400 | [diff] [blame] | 256 | /** |
Tejun Heo | 87e1d78 | 2015-05-28 14:50:52 -0400 | [diff] [blame] | 257 | * locked_inode_to_wb_and_lock_list - determine a locked inode's wb and lock it |
| 258 | * @inode: inode of interest with i_lock held |
| 259 | * |
| 260 | * Returns @inode's wb with its list_lock held. @inode->i_lock must be |
| 261 | * held on entry and is released on return. The returned wb is guaranteed |
| 262 | * to stay @inode's associated wb until its list_lock is released. |
| 263 | */ |
| 264 | static struct bdi_writeback * |
| 265 | locked_inode_to_wb_and_lock_list(struct inode *inode) |
| 266 | __releases(&inode->i_lock) |
| 267 | __acquires(&wb->list_lock) |
| 268 | { |
| 269 | while (true) { |
| 270 | struct bdi_writeback *wb = inode_to_wb(inode); |
| 271 | |
| 272 | /* |
| 273 | * inode_to_wb() association is protected by both |
| 274 | * @inode->i_lock and @wb->list_lock but list_lock nests |
| 275 | * outside i_lock. Drop i_lock and verify that the |
| 276 | * association hasn't changed after acquiring list_lock. |
| 277 | */ |
| 278 | wb_get(wb); |
| 279 | spin_unlock(&inode->i_lock); |
| 280 | spin_lock(&wb->list_lock); |
| 281 | wb_put(wb); /* not gonna deref it anymore */ |
| 282 | |
Tejun Heo | aaa2cac | 2015-05-28 14:50:55 -0400 | [diff] [blame] | 283 | /* i_wb may have changed inbetween, can't use inode_to_wb() */ |
| 284 | if (likely(wb == inode->i_wb)) |
Tejun Heo | 87e1d78 | 2015-05-28 14:50:52 -0400 | [diff] [blame] | 285 | return wb; /* @inode already has ref */ |
| 286 | |
| 287 | spin_unlock(&wb->list_lock); |
| 288 | cpu_relax(); |
| 289 | spin_lock(&inode->i_lock); |
| 290 | } |
| 291 | } |
| 292 | |
| 293 | /** |
| 294 | * inode_to_wb_and_lock_list - determine an inode's wb and lock it |
| 295 | * @inode: inode of interest |
| 296 | * |
| 297 | * Same as locked_inode_to_wb_and_lock_list() but @inode->i_lock isn't held |
| 298 | * on entry. |
| 299 | */ |
| 300 | static struct bdi_writeback *inode_to_wb_and_lock_list(struct inode *inode) |
| 301 | __acquires(&wb->list_lock) |
| 302 | { |
| 303 | spin_lock(&inode->i_lock); |
| 304 | return locked_inode_to_wb_and_lock_list(inode); |
| 305 | } |
| 306 | |
Tejun Heo | 682aa8e | 2015-05-28 14:50:53 -0400 | [diff] [blame] | 307 | struct inode_switch_wbs_context { |
| 308 | struct inode *inode; |
| 309 | struct bdi_writeback *new_wb; |
| 310 | |
| 311 | struct rcu_head rcu_head; |
| 312 | struct work_struct work; |
| 313 | }; |
| 314 | |
| 315 | static void inode_switch_wbs_work_fn(struct work_struct *work) |
| 316 | { |
| 317 | struct inode_switch_wbs_context *isw = |
| 318 | container_of(work, struct inode_switch_wbs_context, work); |
| 319 | struct inode *inode = isw->inode; |
Tejun Heo | d10c809 | 2015-05-28 14:50:56 -0400 | [diff] [blame] | 320 | struct address_space *mapping = inode->i_mapping; |
| 321 | struct bdi_writeback *old_wb = inode->i_wb; |
Tejun Heo | 682aa8e | 2015-05-28 14:50:53 -0400 | [diff] [blame] | 322 | struct bdi_writeback *new_wb = isw->new_wb; |
Tejun Heo | d10c809 | 2015-05-28 14:50:56 -0400 | [diff] [blame] | 323 | struct radix_tree_iter iter; |
| 324 | bool switched = false; |
| 325 | void **slot; |
Tejun Heo | 682aa8e | 2015-05-28 14:50:53 -0400 | [diff] [blame] | 326 | |
| 327 | /* |
| 328 | * By the time control reaches here, RCU grace period has passed |
| 329 | * since I_WB_SWITCH assertion and all wb stat update transactions |
| 330 | * between unlocked_inode_to_wb_begin/end() are guaranteed to be |
| 331 | * synchronizing against mapping->tree_lock. |
Tejun Heo | d10c809 | 2015-05-28 14:50:56 -0400 | [diff] [blame] | 332 | * |
| 333 | * Grabbing old_wb->list_lock, inode->i_lock and mapping->tree_lock |
| 334 | * gives us exclusion against all wb related operations on @inode |
| 335 | * including IO list manipulations and stat updates. |
Tejun Heo | 682aa8e | 2015-05-28 14:50:53 -0400 | [diff] [blame] | 336 | */ |
Tejun Heo | d10c809 | 2015-05-28 14:50:56 -0400 | [diff] [blame] | 337 | if (old_wb < new_wb) { |
| 338 | spin_lock(&old_wb->list_lock); |
| 339 | spin_lock_nested(&new_wb->list_lock, SINGLE_DEPTH_NESTING); |
| 340 | } else { |
| 341 | spin_lock(&new_wb->list_lock); |
| 342 | spin_lock_nested(&old_wb->list_lock, SINGLE_DEPTH_NESTING); |
| 343 | } |
Tejun Heo | 682aa8e | 2015-05-28 14:50:53 -0400 | [diff] [blame] | 344 | spin_lock(&inode->i_lock); |
Tejun Heo | d10c809 | 2015-05-28 14:50:56 -0400 | [diff] [blame] | 345 | spin_lock_irq(&mapping->tree_lock); |
Tejun Heo | 682aa8e | 2015-05-28 14:50:53 -0400 | [diff] [blame] | 346 | |
Tejun Heo | d10c809 | 2015-05-28 14:50:56 -0400 | [diff] [blame] | 347 | /* |
| 348 | * Once I_FREEING is visible under i_lock, the eviction path owns |
Dave Chinner | c7f5408 | 2015-03-04 14:07:22 -0500 | [diff] [blame] | 349 | * the inode and we shouldn't modify ->i_io_list. |
Tejun Heo | d10c809 | 2015-05-28 14:50:56 -0400 | [diff] [blame] | 350 | */ |
| 351 | if (unlikely(inode->i_state & I_FREEING)) |
| 352 | goto skip_switch; |
| 353 | |
| 354 | /* |
| 355 | * Count and transfer stats. Note that PAGECACHE_TAG_DIRTY points |
| 356 | * to possibly dirty pages while PAGECACHE_TAG_WRITEBACK points to |
| 357 | * pages actually under underwriteback. |
| 358 | */ |
| 359 | radix_tree_for_each_tagged(slot, &mapping->page_tree, &iter, 0, |
| 360 | PAGECACHE_TAG_DIRTY) { |
| 361 | struct page *page = radix_tree_deref_slot_protected(slot, |
| 362 | &mapping->tree_lock); |
| 363 | if (likely(page) && PageDirty(page)) { |
| 364 | __dec_wb_stat(old_wb, WB_RECLAIMABLE); |
| 365 | __inc_wb_stat(new_wb, WB_RECLAIMABLE); |
| 366 | } |
| 367 | } |
| 368 | |
| 369 | radix_tree_for_each_tagged(slot, &mapping->page_tree, &iter, 0, |
| 370 | PAGECACHE_TAG_WRITEBACK) { |
| 371 | struct page *page = radix_tree_deref_slot_protected(slot, |
| 372 | &mapping->tree_lock); |
| 373 | if (likely(page)) { |
| 374 | WARN_ON_ONCE(!PageWriteback(page)); |
| 375 | __dec_wb_stat(old_wb, WB_WRITEBACK); |
| 376 | __inc_wb_stat(new_wb, WB_WRITEBACK); |
| 377 | } |
| 378 | } |
| 379 | |
| 380 | wb_get(new_wb); |
| 381 | |
| 382 | /* |
| 383 | * Transfer to @new_wb's IO list if necessary. The specific list |
| 384 | * @inode was on is ignored and the inode is put on ->b_dirty which |
| 385 | * is always correct including from ->b_dirty_time. The transfer |
| 386 | * preserves @inode->dirtied_when ordering. |
| 387 | */ |
Dave Chinner | c7f5408 | 2015-03-04 14:07:22 -0500 | [diff] [blame] | 388 | if (!list_empty(&inode->i_io_list)) { |
Tejun Heo | d10c809 | 2015-05-28 14:50:56 -0400 | [diff] [blame] | 389 | struct inode *pos; |
| 390 | |
Dave Chinner | c7f5408 | 2015-03-04 14:07:22 -0500 | [diff] [blame] | 391 | inode_io_list_del_locked(inode, old_wb); |
Tejun Heo | d10c809 | 2015-05-28 14:50:56 -0400 | [diff] [blame] | 392 | inode->i_wb = new_wb; |
Dave Chinner | c7f5408 | 2015-03-04 14:07:22 -0500 | [diff] [blame] | 393 | list_for_each_entry(pos, &new_wb->b_dirty, i_io_list) |
Tejun Heo | d10c809 | 2015-05-28 14:50:56 -0400 | [diff] [blame] | 394 | if (time_after_eq(inode->dirtied_when, |
| 395 | pos->dirtied_when)) |
| 396 | break; |
Dave Chinner | c7f5408 | 2015-03-04 14:07:22 -0500 | [diff] [blame] | 397 | inode_io_list_move_locked(inode, new_wb, pos->i_io_list.prev); |
Tejun Heo | d10c809 | 2015-05-28 14:50:56 -0400 | [diff] [blame] | 398 | } else { |
| 399 | inode->i_wb = new_wb; |
| 400 | } |
| 401 | |
| 402 | /* ->i_wb_frn updates may race wbc_detach_inode() but doesn't matter */ |
Tejun Heo | 682aa8e | 2015-05-28 14:50:53 -0400 | [diff] [blame] | 403 | inode->i_wb_frn_winner = 0; |
| 404 | inode->i_wb_frn_avg_time = 0; |
| 405 | inode->i_wb_frn_history = 0; |
Tejun Heo | d10c809 | 2015-05-28 14:50:56 -0400 | [diff] [blame] | 406 | switched = true; |
| 407 | skip_switch: |
Tejun Heo | 682aa8e | 2015-05-28 14:50:53 -0400 | [diff] [blame] | 408 | /* |
| 409 | * Paired with load_acquire in unlocked_inode_to_wb_begin() and |
| 410 | * ensures that the new wb is visible if they see !I_WB_SWITCH. |
| 411 | */ |
| 412 | smp_store_release(&inode->i_state, inode->i_state & ~I_WB_SWITCH); |
| 413 | |
Tejun Heo | d10c809 | 2015-05-28 14:50:56 -0400 | [diff] [blame] | 414 | spin_unlock_irq(&mapping->tree_lock); |
Tejun Heo | 682aa8e | 2015-05-28 14:50:53 -0400 | [diff] [blame] | 415 | spin_unlock(&inode->i_lock); |
Tejun Heo | d10c809 | 2015-05-28 14:50:56 -0400 | [diff] [blame] | 416 | spin_unlock(&new_wb->list_lock); |
| 417 | spin_unlock(&old_wb->list_lock); |
| 418 | |
| 419 | if (switched) { |
| 420 | wb_wakeup(new_wb); |
| 421 | wb_put(old_wb); |
| 422 | } |
| 423 | wb_put(new_wb); |
Tejun Heo | 682aa8e | 2015-05-28 14:50:53 -0400 | [diff] [blame] | 424 | |
| 425 | iput(inode); |
Tejun Heo | 682aa8e | 2015-05-28 14:50:53 -0400 | [diff] [blame] | 426 | kfree(isw); |
| 427 | } |
| 428 | |
| 429 | static void inode_switch_wbs_rcu_fn(struct rcu_head *rcu_head) |
| 430 | { |
| 431 | struct inode_switch_wbs_context *isw = container_of(rcu_head, |
| 432 | struct inode_switch_wbs_context, rcu_head); |
| 433 | |
| 434 | /* needs to grab bh-unsafe locks, bounce to work item */ |
| 435 | INIT_WORK(&isw->work, inode_switch_wbs_work_fn); |
| 436 | schedule_work(&isw->work); |
| 437 | } |
| 438 | |
| 439 | /** |
| 440 | * inode_switch_wbs - change the wb association of an inode |
| 441 | * @inode: target inode |
| 442 | * @new_wb_id: ID of the new wb |
| 443 | * |
| 444 | * Switch @inode's wb association to the wb identified by @new_wb_id. The |
| 445 | * switching is performed asynchronously and may fail silently. |
| 446 | */ |
| 447 | static void inode_switch_wbs(struct inode *inode, int new_wb_id) |
| 448 | { |
| 449 | struct backing_dev_info *bdi = inode_to_bdi(inode); |
| 450 | struct cgroup_subsys_state *memcg_css; |
| 451 | struct inode_switch_wbs_context *isw; |
| 452 | |
| 453 | /* noop if seems to be already in progress */ |
| 454 | if (inode->i_state & I_WB_SWITCH) |
| 455 | return; |
| 456 | |
| 457 | isw = kzalloc(sizeof(*isw), GFP_ATOMIC); |
| 458 | if (!isw) |
| 459 | return; |
| 460 | |
| 461 | /* find and pin the new wb */ |
| 462 | rcu_read_lock(); |
| 463 | memcg_css = css_from_id(new_wb_id, &memory_cgrp_subsys); |
| 464 | if (memcg_css) |
| 465 | isw->new_wb = wb_get_create(bdi, memcg_css, GFP_ATOMIC); |
| 466 | rcu_read_unlock(); |
| 467 | if (!isw->new_wb) |
| 468 | goto out_free; |
| 469 | |
| 470 | /* while holding I_WB_SWITCH, no one else can update the association */ |
| 471 | spin_lock(&inode->i_lock); |
| 472 | if (inode->i_state & (I_WB_SWITCH | I_FREEING) || |
| 473 | inode_to_wb(inode) == isw->new_wb) { |
| 474 | spin_unlock(&inode->i_lock); |
| 475 | goto out_free; |
| 476 | } |
| 477 | inode->i_state |= I_WB_SWITCH; |
| 478 | spin_unlock(&inode->i_lock); |
| 479 | |
| 480 | ihold(inode); |
| 481 | isw->inode = inode; |
| 482 | |
| 483 | /* |
| 484 | * In addition to synchronizing among switchers, I_WB_SWITCH tells |
| 485 | * the RCU protected stat update paths to grab the mapping's |
| 486 | * tree_lock so that stat transfer can synchronize against them. |
| 487 | * Let's continue after I_WB_SWITCH is guaranteed to be visible. |
| 488 | */ |
| 489 | call_rcu(&isw->rcu_head, inode_switch_wbs_rcu_fn); |
| 490 | return; |
| 491 | |
| 492 | out_free: |
| 493 | if (isw->new_wb) |
| 494 | wb_put(isw->new_wb); |
| 495 | kfree(isw); |
| 496 | } |
| 497 | |
Tejun Heo | 87e1d78 | 2015-05-28 14:50:52 -0400 | [diff] [blame] | 498 | /** |
Tejun Heo | b16b1de | 2015-06-02 08:39:48 -0600 | [diff] [blame] | 499 | * wbc_attach_and_unlock_inode - associate wbc with target inode and unlock it |
| 500 | * @wbc: writeback_control of interest |
| 501 | * @inode: target inode |
| 502 | * |
| 503 | * @inode is locked and about to be written back under the control of @wbc. |
| 504 | * Record @inode's writeback context into @wbc and unlock the i_lock. On |
| 505 | * writeback completion, wbc_detach_inode() should be called. This is used |
| 506 | * to track the cgroup writeback context. |
| 507 | */ |
| 508 | void wbc_attach_and_unlock_inode(struct writeback_control *wbc, |
| 509 | struct inode *inode) |
| 510 | { |
Tejun Heo | dd73e4b | 2015-06-16 18:48:30 -0400 | [diff] [blame] | 511 | if (!inode_cgwb_enabled(inode)) { |
| 512 | spin_unlock(&inode->i_lock); |
| 513 | return; |
| 514 | } |
| 515 | |
Tejun Heo | b16b1de | 2015-06-02 08:39:48 -0600 | [diff] [blame] | 516 | wbc->wb = inode_to_wb(inode); |
Tejun Heo | 2a81490 | 2015-05-28 14:50:51 -0400 | [diff] [blame] | 517 | wbc->inode = inode; |
| 518 | |
| 519 | wbc->wb_id = wbc->wb->memcg_css->id; |
| 520 | wbc->wb_lcand_id = inode->i_wb_frn_winner; |
| 521 | wbc->wb_tcand_id = 0; |
| 522 | wbc->wb_bytes = 0; |
| 523 | wbc->wb_lcand_bytes = 0; |
| 524 | wbc->wb_tcand_bytes = 0; |
| 525 | |
Tejun Heo | b16b1de | 2015-06-02 08:39:48 -0600 | [diff] [blame] | 526 | wb_get(wbc->wb); |
| 527 | spin_unlock(&inode->i_lock); |
Tejun Heo | e8a7abf | 2015-05-28 14:50:57 -0400 | [diff] [blame] | 528 | |
| 529 | /* |
| 530 | * A dying wb indicates that the memcg-blkcg mapping has changed |
| 531 | * and a new wb is already serving the memcg. Switch immediately. |
| 532 | */ |
| 533 | if (unlikely(wb_dying(wbc->wb))) |
| 534 | inode_switch_wbs(inode, wbc->wb_id); |
Tejun Heo | b16b1de | 2015-06-02 08:39:48 -0600 | [diff] [blame] | 535 | } |
| 536 | |
| 537 | /** |
Tejun Heo | 2a81490 | 2015-05-28 14:50:51 -0400 | [diff] [blame] | 538 | * wbc_detach_inode - disassociate wbc from inode and perform foreign detection |
| 539 | * @wbc: writeback_control of the just finished writeback |
Tejun Heo | b16b1de | 2015-06-02 08:39:48 -0600 | [diff] [blame] | 540 | * |
| 541 | * To be called after a writeback attempt of an inode finishes and undoes |
| 542 | * wbc_attach_and_unlock_inode(). Can be called under any context. |
Tejun Heo | 2a81490 | 2015-05-28 14:50:51 -0400 | [diff] [blame] | 543 | * |
| 544 | * As concurrent write sharing of an inode is expected to be very rare and |
| 545 | * memcg only tracks page ownership on first-use basis severely confining |
| 546 | * the usefulness of such sharing, cgroup writeback tracks ownership |
| 547 | * per-inode. While the support for concurrent write sharing of an inode |
| 548 | * is deemed unnecessary, an inode being written to by different cgroups at |
| 549 | * different points in time is a lot more common, and, more importantly, |
| 550 | * charging only by first-use can too readily lead to grossly incorrect |
| 551 | * behaviors (single foreign page can lead to gigabytes of writeback to be |
| 552 | * incorrectly attributed). |
| 553 | * |
| 554 | * To resolve this issue, cgroup writeback detects the majority dirtier of |
| 555 | * an inode and transfers the ownership to it. To avoid unnnecessary |
| 556 | * oscillation, the detection mechanism keeps track of history and gives |
| 557 | * out the switch verdict only if the foreign usage pattern is stable over |
| 558 | * a certain amount of time and/or writeback attempts. |
| 559 | * |
| 560 | * On each writeback attempt, @wbc tries to detect the majority writer |
| 561 | * using Boyer-Moore majority vote algorithm. In addition to the byte |
| 562 | * count from the majority voting, it also counts the bytes written for the |
| 563 | * current wb and the last round's winner wb (max of last round's current |
| 564 | * wb, the winner from two rounds ago, and the last round's majority |
| 565 | * candidate). Keeping track of the historical winner helps the algorithm |
| 566 | * to semi-reliably detect the most active writer even when it's not the |
| 567 | * absolute majority. |
| 568 | * |
| 569 | * Once the winner of the round is determined, whether the winner is |
| 570 | * foreign or not and how much IO time the round consumed is recorded in |
| 571 | * inode->i_wb_frn_history. If the amount of recorded foreign IO time is |
| 572 | * over a certain threshold, the switch verdict is given. |
Tejun Heo | b16b1de | 2015-06-02 08:39:48 -0600 | [diff] [blame] | 573 | */ |
| 574 | void wbc_detach_inode(struct writeback_control *wbc) |
| 575 | { |
Tejun Heo | 2a81490 | 2015-05-28 14:50:51 -0400 | [diff] [blame] | 576 | struct bdi_writeback *wb = wbc->wb; |
| 577 | struct inode *inode = wbc->inode; |
Tejun Heo | dd73e4b | 2015-06-16 18:48:30 -0400 | [diff] [blame] | 578 | unsigned long avg_time, max_bytes, max_time; |
| 579 | u16 history; |
Tejun Heo | 2a81490 | 2015-05-28 14:50:51 -0400 | [diff] [blame] | 580 | int max_id; |
| 581 | |
Tejun Heo | dd73e4b | 2015-06-16 18:48:30 -0400 | [diff] [blame] | 582 | if (!wb) |
| 583 | return; |
| 584 | |
| 585 | history = inode->i_wb_frn_history; |
| 586 | avg_time = inode->i_wb_frn_avg_time; |
| 587 | |
Tejun Heo | 2a81490 | 2015-05-28 14:50:51 -0400 | [diff] [blame] | 588 | /* pick the winner of this round */ |
| 589 | if (wbc->wb_bytes >= wbc->wb_lcand_bytes && |
| 590 | wbc->wb_bytes >= wbc->wb_tcand_bytes) { |
| 591 | max_id = wbc->wb_id; |
| 592 | max_bytes = wbc->wb_bytes; |
| 593 | } else if (wbc->wb_lcand_bytes >= wbc->wb_tcand_bytes) { |
| 594 | max_id = wbc->wb_lcand_id; |
| 595 | max_bytes = wbc->wb_lcand_bytes; |
| 596 | } else { |
| 597 | max_id = wbc->wb_tcand_id; |
| 598 | max_bytes = wbc->wb_tcand_bytes; |
| 599 | } |
| 600 | |
| 601 | /* |
| 602 | * Calculate the amount of IO time the winner consumed and fold it |
| 603 | * into the running average kept per inode. If the consumed IO |
| 604 | * time is lower than avag / WB_FRN_TIME_CUT_DIV, ignore it for |
| 605 | * deciding whether to switch or not. This is to prevent one-off |
| 606 | * small dirtiers from skewing the verdict. |
| 607 | */ |
| 608 | max_time = DIV_ROUND_UP((max_bytes >> PAGE_SHIFT) << WB_FRN_TIME_SHIFT, |
| 609 | wb->avg_write_bandwidth); |
| 610 | if (avg_time) |
| 611 | avg_time += (max_time >> WB_FRN_TIME_AVG_SHIFT) - |
| 612 | (avg_time >> WB_FRN_TIME_AVG_SHIFT); |
| 613 | else |
| 614 | avg_time = max_time; /* immediate catch up on first run */ |
| 615 | |
| 616 | if (max_time >= avg_time / WB_FRN_TIME_CUT_DIV) { |
| 617 | int slots; |
| 618 | |
| 619 | /* |
| 620 | * The switch verdict is reached if foreign wb's consume |
| 621 | * more than a certain proportion of IO time in a |
| 622 | * WB_FRN_TIME_PERIOD. This is loosely tracked by 16 slot |
| 623 | * history mask where each bit represents one sixteenth of |
| 624 | * the period. Determine the number of slots to shift into |
| 625 | * history from @max_time. |
| 626 | */ |
| 627 | slots = min(DIV_ROUND_UP(max_time, WB_FRN_HIST_UNIT), |
| 628 | (unsigned long)WB_FRN_HIST_MAX_SLOTS); |
| 629 | history <<= slots; |
| 630 | if (wbc->wb_id != max_id) |
| 631 | history |= (1U << slots) - 1; |
| 632 | |
| 633 | /* |
| 634 | * Switch if the current wb isn't the consistent winner. |
| 635 | * If there are multiple closely competing dirtiers, the |
| 636 | * inode may switch across them repeatedly over time, which |
| 637 | * is okay. The main goal is avoiding keeping an inode on |
| 638 | * the wrong wb for an extended period of time. |
| 639 | */ |
Tejun Heo | 682aa8e | 2015-05-28 14:50:53 -0400 | [diff] [blame] | 640 | if (hweight32(history) > WB_FRN_HIST_THR_SLOTS) |
| 641 | inode_switch_wbs(inode, max_id); |
Tejun Heo | 2a81490 | 2015-05-28 14:50:51 -0400 | [diff] [blame] | 642 | } |
| 643 | |
| 644 | /* |
| 645 | * Multiple instances of this function may race to update the |
| 646 | * following fields but we don't mind occassional inaccuracies. |
| 647 | */ |
| 648 | inode->i_wb_frn_winner = max_id; |
| 649 | inode->i_wb_frn_avg_time = min(avg_time, (unsigned long)U16_MAX); |
| 650 | inode->i_wb_frn_history = history; |
| 651 | |
Tejun Heo | b16b1de | 2015-06-02 08:39:48 -0600 | [diff] [blame] | 652 | wb_put(wbc->wb); |
| 653 | wbc->wb = NULL; |
| 654 | } |
| 655 | |
| 656 | /** |
Tejun Heo | 2a81490 | 2015-05-28 14:50:51 -0400 | [diff] [blame] | 657 | * wbc_account_io - account IO issued during writeback |
| 658 | * @wbc: writeback_control of the writeback in progress |
| 659 | * @page: page being written out |
| 660 | * @bytes: number of bytes being written out |
| 661 | * |
| 662 | * @bytes from @page are about to written out during the writeback |
| 663 | * controlled by @wbc. Keep the book for foreign inode detection. See |
| 664 | * wbc_detach_inode(). |
| 665 | */ |
| 666 | void wbc_account_io(struct writeback_control *wbc, struct page *page, |
| 667 | size_t bytes) |
| 668 | { |
| 669 | int id; |
| 670 | |
| 671 | /* |
| 672 | * pageout() path doesn't attach @wbc to the inode being written |
| 673 | * out. This is intentional as we don't want the function to block |
| 674 | * behind a slow cgroup. Ultimately, we want pageout() to kick off |
| 675 | * regular writeback instead of writing things out itself. |
| 676 | */ |
| 677 | if (!wbc->wb) |
| 678 | return; |
| 679 | |
| 680 | rcu_read_lock(); |
| 681 | id = mem_cgroup_css_from_page(page)->id; |
| 682 | rcu_read_unlock(); |
| 683 | |
| 684 | if (id == wbc->wb_id) { |
| 685 | wbc->wb_bytes += bytes; |
| 686 | return; |
| 687 | } |
| 688 | |
| 689 | if (id == wbc->wb_lcand_id) |
| 690 | wbc->wb_lcand_bytes += bytes; |
| 691 | |
| 692 | /* Boyer-Moore majority vote algorithm */ |
| 693 | if (!wbc->wb_tcand_bytes) |
| 694 | wbc->wb_tcand_id = id; |
| 695 | if (id == wbc->wb_tcand_id) |
| 696 | wbc->wb_tcand_bytes += bytes; |
| 697 | else |
| 698 | wbc->wb_tcand_bytes -= min(bytes, wbc->wb_tcand_bytes); |
| 699 | } |
Tejun Heo | 5aa2a96 | 2015-07-23 14:27:09 -0400 | [diff] [blame] | 700 | EXPORT_SYMBOL_GPL(wbc_account_io); |
Tejun Heo | 2a81490 | 2015-05-28 14:50:51 -0400 | [diff] [blame] | 701 | |
| 702 | /** |
Tejun Heo | 703c270 | 2015-05-22 17:13:44 -0400 | [diff] [blame] | 703 | * inode_congested - test whether an inode is congested |
Tejun Heo | 60292bc | 2015-08-18 14:54:54 -0700 | [diff] [blame] | 704 | * @inode: inode to test for congestion (may be NULL) |
Tejun Heo | 703c270 | 2015-05-22 17:13:44 -0400 | [diff] [blame] | 705 | * @cong_bits: mask of WB_[a]sync_congested bits to test |
| 706 | * |
| 707 | * Tests whether @inode is congested. @cong_bits is the mask of congestion |
| 708 | * bits to test and the return value is the mask of set bits. |
| 709 | * |
| 710 | * If cgroup writeback is enabled for @inode, the congestion state is |
| 711 | * determined by whether the cgwb (cgroup bdi_writeback) for the blkcg |
| 712 | * associated with @inode is congested; otherwise, the root wb's congestion |
| 713 | * state is used. |
Tejun Heo | 60292bc | 2015-08-18 14:54:54 -0700 | [diff] [blame] | 714 | * |
| 715 | * @inode is allowed to be NULL as this function is often called on |
| 716 | * mapping->host which is NULL for the swapper space. |
Tejun Heo | 703c270 | 2015-05-22 17:13:44 -0400 | [diff] [blame] | 717 | */ |
| 718 | int inode_congested(struct inode *inode, int cong_bits) |
| 719 | { |
Tejun Heo | 5cb8b82 | 2015-05-28 14:50:54 -0400 | [diff] [blame] | 720 | /* |
| 721 | * Once set, ->i_wb never becomes NULL while the inode is alive. |
| 722 | * Start transaction iff ->i_wb is visible. |
| 723 | */ |
Tejun Heo | aaa2cac | 2015-05-28 14:50:55 -0400 | [diff] [blame] | 724 | if (inode && inode_to_wb_is_valid(inode)) { |
Tejun Heo | 5cb8b82 | 2015-05-28 14:50:54 -0400 | [diff] [blame] | 725 | struct bdi_writeback *wb; |
| 726 | bool locked, congested; |
| 727 | |
| 728 | wb = unlocked_inode_to_wb_begin(inode, &locked); |
| 729 | congested = wb_congested(wb, cong_bits); |
| 730 | unlocked_inode_to_wb_end(inode, locked); |
| 731 | return congested; |
Tejun Heo | 703c270 | 2015-05-22 17:13:44 -0400 | [diff] [blame] | 732 | } |
| 733 | |
| 734 | return wb_congested(&inode_to_bdi(inode)->wb, cong_bits); |
| 735 | } |
| 736 | EXPORT_SYMBOL_GPL(inode_congested); |
| 737 | |
Tejun Heo | f2b6512 | 2015-05-22 17:13:55 -0400 | [diff] [blame] | 738 | /** |
| 739 | * wb_split_bdi_pages - split nr_pages to write according to bandwidth |
| 740 | * @wb: target bdi_writeback to split @nr_pages to |
| 741 | * @nr_pages: number of pages to write for the whole bdi |
| 742 | * |
| 743 | * Split @wb's portion of @nr_pages according to @wb's write bandwidth in |
| 744 | * relation to the total write bandwidth of all wb's w/ dirty inodes on |
| 745 | * @wb->bdi. |
| 746 | */ |
| 747 | static long wb_split_bdi_pages(struct bdi_writeback *wb, long nr_pages) |
| 748 | { |
| 749 | unsigned long this_bw = wb->avg_write_bandwidth; |
| 750 | unsigned long tot_bw = atomic_long_read(&wb->bdi->tot_write_bandwidth); |
| 751 | |
| 752 | if (nr_pages == LONG_MAX) |
| 753 | return LONG_MAX; |
| 754 | |
| 755 | /* |
| 756 | * This may be called on clean wb's and proportional distribution |
| 757 | * may not make sense, just use the original @nr_pages in those |
| 758 | * cases. In general, we wanna err on the side of writing more. |
| 759 | */ |
| 760 | if (!tot_bw || this_bw >= tot_bw) |
| 761 | return nr_pages; |
| 762 | else |
| 763 | return DIV_ROUND_UP_ULL((u64)nr_pages * this_bw, tot_bw); |
| 764 | } |
| 765 | |
Tejun Heo | db12536 | 2015-05-22 17:14:01 -0400 | [diff] [blame] | 766 | /** |
Tejun Heo | db12536 | 2015-05-22 17:14:01 -0400 | [diff] [blame] | 767 | * bdi_split_work_to_wbs - split a wb_writeback_work to all wb's of a bdi |
| 768 | * @bdi: target backing_dev_info |
| 769 | * @base_work: wb_writeback_work to issue |
| 770 | * @skip_if_busy: skip wb's which already have writeback in progress |
| 771 | * |
| 772 | * Split and issue @base_work to all wb's (bdi_writeback's) of @bdi which |
| 773 | * have dirty inodes. If @base_work->nr_page isn't %LONG_MAX, it's |
| 774 | * distributed to the busy wbs according to each wb's proportion in the |
| 775 | * total active write bandwidth of @bdi. |
| 776 | */ |
| 777 | static void bdi_split_work_to_wbs(struct backing_dev_info *bdi, |
| 778 | struct wb_writeback_work *base_work, |
| 779 | bool skip_if_busy) |
| 780 | { |
Tejun Heo | b817525 | 2015-10-02 14:47:05 -0400 | [diff] [blame] | 781 | struct bdi_writeback *last_wb = NULL; |
Tejun Heo | b33e18f | 2015-10-27 14:19:39 +0900 | [diff] [blame^] | 782 | struct bdi_writeback *wb = list_entry(&bdi->wb_list, |
| 783 | struct bdi_writeback, bdi_node); |
Tejun Heo | db12536 | 2015-05-22 17:14:01 -0400 | [diff] [blame] | 784 | |
| 785 | might_sleep(); |
Tejun Heo | db12536 | 2015-05-22 17:14:01 -0400 | [diff] [blame] | 786 | restart: |
| 787 | rcu_read_lock(); |
Tejun Heo | b817525 | 2015-10-02 14:47:05 -0400 | [diff] [blame] | 788 | list_for_each_entry_continue_rcu(wb, &bdi->wb_list, bdi_node) { |
Tejun Heo | 8a1270c | 2015-08-18 14:54:53 -0700 | [diff] [blame] | 789 | DEFINE_WB_COMPLETION_ONSTACK(fallback_work_done); |
| 790 | struct wb_writeback_work fallback_work; |
| 791 | struct wb_writeback_work *work; |
| 792 | long nr_pages; |
| 793 | |
Tejun Heo | b817525 | 2015-10-02 14:47:05 -0400 | [diff] [blame] | 794 | if (last_wb) { |
| 795 | wb_put(last_wb); |
| 796 | last_wb = NULL; |
| 797 | } |
| 798 | |
Tejun Heo | 006a097 | 2015-08-25 14:11:52 -0400 | [diff] [blame] | 799 | /* SYNC_ALL writes out I_DIRTY_TIME too */ |
| 800 | if (!wb_has_dirty_io(wb) && |
| 801 | (base_work->sync_mode == WB_SYNC_NONE || |
| 802 | list_empty(&wb->b_dirty_time))) |
| 803 | continue; |
| 804 | if (skip_if_busy && writeback_in_progress(wb)) |
Tejun Heo | db12536 | 2015-05-22 17:14:01 -0400 | [diff] [blame] | 805 | continue; |
| 806 | |
Tejun Heo | 8a1270c | 2015-08-18 14:54:53 -0700 | [diff] [blame] | 807 | nr_pages = wb_split_bdi_pages(wb, base_work->nr_pages); |
| 808 | |
| 809 | work = kmalloc(sizeof(*work), GFP_ATOMIC); |
| 810 | if (work) { |
| 811 | *work = *base_work; |
| 812 | work->nr_pages = nr_pages; |
| 813 | work->auto_free = 1; |
| 814 | wb_queue_work(wb, work); |
| 815 | continue; |
Tejun Heo | db12536 | 2015-05-22 17:14:01 -0400 | [diff] [blame] | 816 | } |
Tejun Heo | 8a1270c | 2015-08-18 14:54:53 -0700 | [diff] [blame] | 817 | |
| 818 | /* alloc failed, execute synchronously using on-stack fallback */ |
| 819 | work = &fallback_work; |
| 820 | *work = *base_work; |
| 821 | work->nr_pages = nr_pages; |
| 822 | work->auto_free = 0; |
| 823 | work->done = &fallback_work_done; |
| 824 | |
| 825 | wb_queue_work(wb, work); |
| 826 | |
Tejun Heo | b817525 | 2015-10-02 14:47:05 -0400 | [diff] [blame] | 827 | /* |
| 828 | * Pin @wb so that it stays on @bdi->wb_list. This allows |
| 829 | * continuing iteration from @wb after dropping and |
| 830 | * regrabbing rcu read lock. |
| 831 | */ |
| 832 | wb_get(wb); |
| 833 | last_wb = wb; |
| 834 | |
Tejun Heo | 8a1270c | 2015-08-18 14:54:53 -0700 | [diff] [blame] | 835 | rcu_read_unlock(); |
| 836 | wb_wait_for_completion(bdi, &fallback_work_done); |
| 837 | goto restart; |
Tejun Heo | db12536 | 2015-05-22 17:14:01 -0400 | [diff] [blame] | 838 | } |
| 839 | rcu_read_unlock(); |
Tejun Heo | b817525 | 2015-10-02 14:47:05 -0400 | [diff] [blame] | 840 | |
| 841 | if (last_wb) |
| 842 | wb_put(last_wb); |
Tejun Heo | db12536 | 2015-05-22 17:14:01 -0400 | [diff] [blame] | 843 | } |
| 844 | |
Tejun Heo | f2b6512 | 2015-05-22 17:13:55 -0400 | [diff] [blame] | 845 | #else /* CONFIG_CGROUP_WRITEBACK */ |
| 846 | |
Tejun Heo | 87e1d78 | 2015-05-28 14:50:52 -0400 | [diff] [blame] | 847 | static struct bdi_writeback * |
| 848 | locked_inode_to_wb_and_lock_list(struct inode *inode) |
| 849 | __releases(&inode->i_lock) |
| 850 | __acquires(&wb->list_lock) |
| 851 | { |
| 852 | struct bdi_writeback *wb = inode_to_wb(inode); |
| 853 | |
| 854 | spin_unlock(&inode->i_lock); |
| 855 | spin_lock(&wb->list_lock); |
| 856 | return wb; |
| 857 | } |
| 858 | |
| 859 | static struct bdi_writeback *inode_to_wb_and_lock_list(struct inode *inode) |
| 860 | __acquires(&wb->list_lock) |
| 861 | { |
| 862 | struct bdi_writeback *wb = inode_to_wb(inode); |
| 863 | |
| 864 | spin_lock(&wb->list_lock); |
| 865 | return wb; |
| 866 | } |
| 867 | |
Tejun Heo | f2b6512 | 2015-05-22 17:13:55 -0400 | [diff] [blame] | 868 | static long wb_split_bdi_pages(struct bdi_writeback *wb, long nr_pages) |
| 869 | { |
| 870 | return nr_pages; |
| 871 | } |
| 872 | |
Tejun Heo | db12536 | 2015-05-22 17:14:01 -0400 | [diff] [blame] | 873 | static void bdi_split_work_to_wbs(struct backing_dev_info *bdi, |
| 874 | struct wb_writeback_work *base_work, |
| 875 | bool skip_if_busy) |
| 876 | { |
| 877 | might_sleep(); |
| 878 | |
Tejun Heo | 006a097 | 2015-08-25 14:11:52 -0400 | [diff] [blame] | 879 | if (!skip_if_busy || !writeback_in_progress(&bdi->wb)) { |
Tejun Heo | db12536 | 2015-05-22 17:14:01 -0400 | [diff] [blame] | 880 | base_work->auto_free = 0; |
Tejun Heo | db12536 | 2015-05-22 17:14:01 -0400 | [diff] [blame] | 881 | wb_queue_work(&bdi->wb, base_work); |
| 882 | } |
| 883 | } |
| 884 | |
Tejun Heo | 703c270 | 2015-05-22 17:13:44 -0400 | [diff] [blame] | 885 | #endif /* CONFIG_CGROUP_WRITEBACK */ |
| 886 | |
Tejun Heo | c00ddad | 2015-05-22 17:13:51 -0400 | [diff] [blame] | 887 | void wb_start_writeback(struct bdi_writeback *wb, long nr_pages, |
| 888 | bool range_cyclic, enum wb_reason reason) |
Jens Axboe | b6e5131 | 2009-09-16 15:13:54 +0200 | [diff] [blame] | 889 | { |
Tejun Heo | c00ddad | 2015-05-22 17:13:51 -0400 | [diff] [blame] | 890 | struct wb_writeback_work *work; |
| 891 | |
| 892 | if (!wb_has_dirty_io(wb)) |
| 893 | return; |
| 894 | |
| 895 | /* |
| 896 | * This is WB_SYNC_NONE writeback, so if allocation fails just |
| 897 | * wakeup the thread for old dirty data writeback |
| 898 | */ |
| 899 | work = kzalloc(sizeof(*work), GFP_ATOMIC); |
| 900 | if (!work) { |
Tejun Heo | 5634cc2 | 2015-08-18 14:54:56 -0700 | [diff] [blame] | 901 | trace_writeback_nowork(wb); |
Tejun Heo | c00ddad | 2015-05-22 17:13:51 -0400 | [diff] [blame] | 902 | wb_wakeup(wb); |
| 903 | return; |
| 904 | } |
| 905 | |
| 906 | work->sync_mode = WB_SYNC_NONE; |
| 907 | work->nr_pages = nr_pages; |
| 908 | work->range_cyclic = range_cyclic; |
| 909 | work->reason = reason; |
Tejun Heo | ac7b19a | 2015-05-22 17:13:57 -0400 | [diff] [blame] | 910 | work->auto_free = 1; |
Tejun Heo | c00ddad | 2015-05-22 17:13:51 -0400 | [diff] [blame] | 911 | |
| 912 | wb_queue_work(wb, work); |
Christoph Hellwig | c544419 | 2010-06-08 18:15:15 +0200 | [diff] [blame] | 913 | } |
Wu Fengguang | d3ddec7 | 2009-09-23 20:33:40 +0800 | [diff] [blame] | 914 | |
Christoph Hellwig | c544419 | 2010-06-08 18:15:15 +0200 | [diff] [blame] | 915 | /** |
Tejun Heo | 9ecf4866 | 2015-05-22 17:13:54 -0400 | [diff] [blame] | 916 | * wb_start_background_writeback - start background writeback |
| 917 | * @wb: bdi_writback to write from |
Christoph Hellwig | c544419 | 2010-06-08 18:15:15 +0200 | [diff] [blame] | 918 | * |
| 919 | * Description: |
Jan Kara | 6585027 | 2011-01-13 15:45:44 -0800 | [diff] [blame] | 920 | * This makes sure WB_SYNC_NONE background writeback happens. When |
Tejun Heo | 9ecf4866 | 2015-05-22 17:13:54 -0400 | [diff] [blame] | 921 | * this function returns, it is only guaranteed that for given wb |
Jan Kara | 6585027 | 2011-01-13 15:45:44 -0800 | [diff] [blame] | 922 | * some IO is happening if we are over background dirty threshold. |
| 923 | * Caller need not hold sb s_umount semaphore. |
Christoph Hellwig | c544419 | 2010-06-08 18:15:15 +0200 | [diff] [blame] | 924 | */ |
Tejun Heo | 9ecf4866 | 2015-05-22 17:13:54 -0400 | [diff] [blame] | 925 | void wb_start_background_writeback(struct bdi_writeback *wb) |
Christoph Hellwig | c544419 | 2010-06-08 18:15:15 +0200 | [diff] [blame] | 926 | { |
Jan Kara | 6585027 | 2011-01-13 15:45:44 -0800 | [diff] [blame] | 927 | /* |
| 928 | * We just wake up the flusher thread. It will perform background |
| 929 | * writeback as soon as there is no other work to do. |
| 930 | */ |
Tejun Heo | 5634cc2 | 2015-08-18 14:54:56 -0700 | [diff] [blame] | 931 | trace_writeback_wake_background(wb); |
Tejun Heo | 9ecf4866 | 2015-05-22 17:13:54 -0400 | [diff] [blame] | 932 | wb_wakeup(wb); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 933 | } |
| 934 | |
| 935 | /* |
Dave Chinner | a66979a | 2011-03-22 22:23:41 +1100 | [diff] [blame] | 936 | * Remove the inode from the writeback list it is on. |
| 937 | */ |
Dave Chinner | c7f5408 | 2015-03-04 14:07:22 -0500 | [diff] [blame] | 938 | void inode_io_list_del(struct inode *inode) |
Dave Chinner | a66979a | 2011-03-22 22:23:41 +1100 | [diff] [blame] | 939 | { |
Tejun Heo | 87e1d78 | 2015-05-28 14:50:52 -0400 | [diff] [blame] | 940 | struct bdi_writeback *wb; |
Dave Chinner | a66979a | 2011-03-22 22:23:41 +1100 | [diff] [blame] | 941 | |
Tejun Heo | 87e1d78 | 2015-05-28 14:50:52 -0400 | [diff] [blame] | 942 | wb = inode_to_wb_and_lock_list(inode); |
Dave Chinner | c7f5408 | 2015-03-04 14:07:22 -0500 | [diff] [blame] | 943 | inode_io_list_del_locked(inode, wb); |
Tejun Heo | 52ebea7 | 2015-05-22 17:13:37 -0400 | [diff] [blame] | 944 | spin_unlock(&wb->list_lock); |
Christoph Hellwig | f758eea | 2011-04-21 18:19:44 -0600 | [diff] [blame] | 945 | } |
Dave Chinner | a66979a | 2011-03-22 22:23:41 +1100 | [diff] [blame] | 946 | |
| 947 | /* |
Andrew Morton | 6610a0b | 2007-10-16 23:30:32 -0700 | [diff] [blame] | 948 | * Redirty an inode: set its when-it-was dirtied timestamp and move it to the |
| 949 | * furthest end of its superblock's dirty-inode list. |
| 950 | * |
| 951 | * 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] | 952 | * 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] | 953 | * the case then the inode must have been redirtied while it was being written |
| 954 | * out and we don't reset its dirtied_when. |
| 955 | */ |
Christoph Hellwig | f758eea | 2011-04-21 18:19:44 -0600 | [diff] [blame] | 956 | static void redirty_tail(struct inode *inode, struct bdi_writeback *wb) |
Andrew Morton | 6610a0b | 2007-10-16 23:30:32 -0700 | [diff] [blame] | 957 | { |
Jens Axboe | 03ba378 | 2009-09-09 09:08:54 +0200 | [diff] [blame] | 958 | if (!list_empty(&wb->b_dirty)) { |
Jens Axboe | 66f3b8e | 2009-09-02 09:19:46 +0200 | [diff] [blame] | 959 | struct inode *tail; |
Andrew Morton | 6610a0b | 2007-10-16 23:30:32 -0700 | [diff] [blame] | 960 | |
Nick Piggin | 7ccf19a | 2010-10-21 11:49:30 +1100 | [diff] [blame] | 961 | tail = wb_inode(wb->b_dirty.next); |
Jens Axboe | 66f3b8e | 2009-09-02 09:19:46 +0200 | [diff] [blame] | 962 | if (time_before(inode->dirtied_when, tail->dirtied_when)) |
Andrew Morton | 6610a0b | 2007-10-16 23:30:32 -0700 | [diff] [blame] | 963 | inode->dirtied_when = jiffies; |
| 964 | } |
Dave Chinner | c7f5408 | 2015-03-04 14:07:22 -0500 | [diff] [blame] | 965 | inode_io_list_move_locked(inode, wb, &wb->b_dirty); |
Andrew Morton | 6610a0b | 2007-10-16 23:30:32 -0700 | [diff] [blame] | 966 | } |
| 967 | |
| 968 | /* |
Jens Axboe | 66f3b8e | 2009-09-02 09:19:46 +0200 | [diff] [blame] | 969 | * requeue inode for re-scanning after bdi->b_io list is exhausted. |
Andrew Morton | c986d1e | 2007-10-16 23:30:34 -0700 | [diff] [blame] | 970 | */ |
Christoph Hellwig | f758eea | 2011-04-21 18:19:44 -0600 | [diff] [blame] | 971 | static void requeue_io(struct inode *inode, struct bdi_writeback *wb) |
Andrew Morton | c986d1e | 2007-10-16 23:30:34 -0700 | [diff] [blame] | 972 | { |
Dave Chinner | c7f5408 | 2015-03-04 14:07:22 -0500 | [diff] [blame] | 973 | inode_io_list_move_locked(inode, wb, &wb->b_more_io); |
Andrew Morton | c986d1e | 2007-10-16 23:30:34 -0700 | [diff] [blame] | 974 | } |
| 975 | |
Joern Engel | 1c0eeaf | 2007-10-16 23:30:44 -0700 | [diff] [blame] | 976 | static void inode_sync_complete(struct inode *inode) |
| 977 | { |
Jan Kara | 365b94ae | 2012-05-03 14:47:55 +0200 | [diff] [blame] | 978 | inode->i_state &= ~I_SYNC; |
Jan Kara | 4eff96d | 2012-11-26 16:29:51 -0800 | [diff] [blame] | 979 | /* If inode is clean an unused, put it into LRU now... */ |
| 980 | inode_add_lru(inode); |
Jan Kara | 365b94ae | 2012-05-03 14:47:55 +0200 | [diff] [blame] | 981 | /* Waiters must see I_SYNC cleared before being woken up */ |
Joern Engel | 1c0eeaf | 2007-10-16 23:30:44 -0700 | [diff] [blame] | 982 | smp_mb(); |
| 983 | wake_up_bit(&inode->i_state, __I_SYNC); |
| 984 | } |
| 985 | |
Jeff Layton | d2caa3c5 | 2009-04-02 16:56:37 -0700 | [diff] [blame] | 986 | static bool inode_dirtied_after(struct inode *inode, unsigned long t) |
| 987 | { |
| 988 | bool ret = time_after(inode->dirtied_when, t); |
| 989 | #ifndef CONFIG_64BIT |
| 990 | /* |
| 991 | * For inodes being constantly redirtied, dirtied_when can get stuck. |
| 992 | * It _appears_ to be in the future, but is actually in distant past. |
| 993 | * This test is necessary to prevent such wrapped-around relative times |
Jens Axboe | 5b0830c | 2009-09-23 19:37:09 +0200 | [diff] [blame] | 994 | * from permanently stopping the whole bdi writeback. |
Jeff Layton | d2caa3c5 | 2009-04-02 16:56:37 -0700 | [diff] [blame] | 995 | */ |
| 996 | ret = ret && time_before_eq(inode->dirtied_when, jiffies); |
| 997 | #endif |
| 998 | return ret; |
| 999 | } |
| 1000 | |
Theodore Ts'o | 0ae45f6 | 2015-02-02 00:37:00 -0500 | [diff] [blame] | 1001 | #define EXPIRE_DIRTY_ATIME 0x0001 |
| 1002 | |
Andrew Morton | c986d1e | 2007-10-16 23:30:34 -0700 | [diff] [blame] | 1003 | /* |
Wang Sheng-Hui | 0e2f2b2 | 2012-09-11 08:28:18 +0800 | [diff] [blame] | 1004 | * Move expired (dirtied before work->older_than_this) dirty inodes from |
Jan Kara | 697e6fe | 2012-03-09 07:26:22 -0800 | [diff] [blame] | 1005 | * @delaying_queue to @dispatch_queue. |
Fengguang Wu | 2c13657 | 2007-10-16 23:30:39 -0700 | [diff] [blame] | 1006 | */ |
Wu Fengguang | e84d0a4 | 2011-04-23 12:27:27 -0600 | [diff] [blame] | 1007 | static int move_expired_inodes(struct list_head *delaying_queue, |
Fengguang Wu | 2c13657 | 2007-10-16 23:30:39 -0700 | [diff] [blame] | 1008 | struct list_head *dispatch_queue, |
Theodore Ts'o | 0ae45f6 | 2015-02-02 00:37:00 -0500 | [diff] [blame] | 1009 | int flags, |
Curt Wohlgemuth | ad4e38d | 2011-10-07 21:51:56 -0600 | [diff] [blame] | 1010 | struct wb_writeback_work *work) |
Fengguang Wu | 2c13657 | 2007-10-16 23:30:39 -0700 | [diff] [blame] | 1011 | { |
Theodore Ts'o | 0ae45f6 | 2015-02-02 00:37:00 -0500 | [diff] [blame] | 1012 | unsigned long *older_than_this = NULL; |
| 1013 | unsigned long expire_time; |
Shaohua Li | 5c03449 | 2009-09-24 14:42:33 +0200 | [diff] [blame] | 1014 | LIST_HEAD(tmp); |
| 1015 | struct list_head *pos, *node; |
Jens Axboe | cf13730 | 2009-09-24 15:12:57 +0200 | [diff] [blame] | 1016 | struct super_block *sb = NULL; |
Shaohua Li | 5c03449 | 2009-09-24 14:42:33 +0200 | [diff] [blame] | 1017 | struct inode *inode; |
Jens Axboe | cf13730 | 2009-09-24 15:12:57 +0200 | [diff] [blame] | 1018 | int do_sb_sort = 0; |
Wu Fengguang | e84d0a4 | 2011-04-23 12:27:27 -0600 | [diff] [blame] | 1019 | int moved = 0; |
Shaohua Li | 5c03449 | 2009-09-24 14:42:33 +0200 | [diff] [blame] | 1020 | |
Theodore Ts'o | 0ae45f6 | 2015-02-02 00:37:00 -0500 | [diff] [blame] | 1021 | if ((flags & EXPIRE_DIRTY_ATIME) == 0) |
| 1022 | older_than_this = work->older_than_this; |
Theodore Ts'o | a2f4870 | 2015-03-17 12:23:19 -0400 | [diff] [blame] | 1023 | else if (!work->for_sync) { |
| 1024 | expire_time = jiffies - (dirtytime_expire_interval * HZ); |
Theodore Ts'o | 0ae45f6 | 2015-02-02 00:37:00 -0500 | [diff] [blame] | 1025 | older_than_this = &expire_time; |
| 1026 | } |
Fengguang Wu | 2c13657 | 2007-10-16 23:30:39 -0700 | [diff] [blame] | 1027 | while (!list_empty(delaying_queue)) { |
Nick Piggin | 7ccf19a | 2010-10-21 11:49:30 +1100 | [diff] [blame] | 1028 | inode = wb_inode(delaying_queue->prev); |
Theodore Ts'o | 0ae45f6 | 2015-02-02 00:37:00 -0500 | [diff] [blame] | 1029 | if (older_than_this && |
| 1030 | inode_dirtied_after(inode, *older_than_this)) |
Fengguang Wu | 2c13657 | 2007-10-16 23:30:39 -0700 | [diff] [blame] | 1031 | break; |
Dave Chinner | c7f5408 | 2015-03-04 14:07:22 -0500 | [diff] [blame] | 1032 | list_move(&inode->i_io_list, &tmp); |
Jan Kara | a885599 | 2013-07-09 22:36:45 +0800 | [diff] [blame] | 1033 | moved++; |
Theodore Ts'o | 0ae45f6 | 2015-02-02 00:37:00 -0500 | [diff] [blame] | 1034 | if (flags & EXPIRE_DIRTY_ATIME) |
| 1035 | set_bit(__I_DIRTY_TIME_EXPIRED, &inode->i_state); |
Jan Kara | a885599 | 2013-07-09 22:36:45 +0800 | [diff] [blame] | 1036 | if (sb_is_blkdev_sb(inode->i_sb)) |
| 1037 | continue; |
Jens Axboe | cf13730 | 2009-09-24 15:12:57 +0200 | [diff] [blame] | 1038 | if (sb && sb != inode->i_sb) |
| 1039 | do_sb_sort = 1; |
| 1040 | sb = inode->i_sb; |
Shaohua Li | 5c03449 | 2009-09-24 14:42:33 +0200 | [diff] [blame] | 1041 | } |
| 1042 | |
Jens Axboe | cf13730 | 2009-09-24 15:12:57 +0200 | [diff] [blame] | 1043 | /* just one sb in list, splice to dispatch_queue and we're done */ |
| 1044 | if (!do_sb_sort) { |
| 1045 | list_splice(&tmp, dispatch_queue); |
Wu Fengguang | e84d0a4 | 2011-04-23 12:27:27 -0600 | [diff] [blame] | 1046 | goto out; |
Jens Axboe | cf13730 | 2009-09-24 15:12:57 +0200 | [diff] [blame] | 1047 | } |
| 1048 | |
Shaohua Li | 5c03449 | 2009-09-24 14:42:33 +0200 | [diff] [blame] | 1049 | /* Move inodes from one superblock together */ |
| 1050 | while (!list_empty(&tmp)) { |
Nick Piggin | 7ccf19a | 2010-10-21 11:49:30 +1100 | [diff] [blame] | 1051 | sb = wb_inode(tmp.prev)->i_sb; |
Shaohua Li | 5c03449 | 2009-09-24 14:42:33 +0200 | [diff] [blame] | 1052 | list_for_each_prev_safe(pos, node, &tmp) { |
Nick Piggin | 7ccf19a | 2010-10-21 11:49:30 +1100 | [diff] [blame] | 1053 | inode = wb_inode(pos); |
Shaohua Li | 5c03449 | 2009-09-24 14:42:33 +0200 | [diff] [blame] | 1054 | if (inode->i_sb == sb) |
Dave Chinner | c7f5408 | 2015-03-04 14:07:22 -0500 | [diff] [blame] | 1055 | list_move(&inode->i_io_list, dispatch_queue); |
Shaohua Li | 5c03449 | 2009-09-24 14:42:33 +0200 | [diff] [blame] | 1056 | } |
Fengguang Wu | 2c13657 | 2007-10-16 23:30:39 -0700 | [diff] [blame] | 1057 | } |
Wu Fengguang | e84d0a4 | 2011-04-23 12:27:27 -0600 | [diff] [blame] | 1058 | out: |
| 1059 | return moved; |
Fengguang Wu | 2c13657 | 2007-10-16 23:30:39 -0700 | [diff] [blame] | 1060 | } |
| 1061 | |
| 1062 | /* |
| 1063 | * Queue all expired dirty inodes for io, eldest first. |
Wu Fengguang | 4ea879b | 2010-08-11 14:17:42 -0700 | [diff] [blame] | 1064 | * Before |
| 1065 | * newly dirtied b_dirty b_io b_more_io |
| 1066 | * =============> gf edc BA |
| 1067 | * After |
| 1068 | * newly dirtied b_dirty b_io b_more_io |
| 1069 | * =============> g fBAedc |
| 1070 | * | |
| 1071 | * +--> dequeue for IO |
Fengguang Wu | 2c13657 | 2007-10-16 23:30:39 -0700 | [diff] [blame] | 1072 | */ |
Curt Wohlgemuth | ad4e38d | 2011-10-07 21:51:56 -0600 | [diff] [blame] | 1073 | static void queue_io(struct bdi_writeback *wb, struct wb_writeback_work *work) |
Fengguang Wu | 2c13657 | 2007-10-16 23:30:39 -0700 | [diff] [blame] | 1074 | { |
Wu Fengguang | e84d0a4 | 2011-04-23 12:27:27 -0600 | [diff] [blame] | 1075 | int moved; |
Theodore Ts'o | 0ae45f6 | 2015-02-02 00:37:00 -0500 | [diff] [blame] | 1076 | |
Christoph Hellwig | f758eea | 2011-04-21 18:19:44 -0600 | [diff] [blame] | 1077 | assert_spin_locked(&wb->list_lock); |
Wu Fengguang | 4ea879b | 2010-08-11 14:17:42 -0700 | [diff] [blame] | 1078 | list_splice_init(&wb->b_more_io, &wb->b_io); |
Theodore Ts'o | 0ae45f6 | 2015-02-02 00:37:00 -0500 | [diff] [blame] | 1079 | moved = move_expired_inodes(&wb->b_dirty, &wb->b_io, 0, work); |
| 1080 | moved += move_expired_inodes(&wb->b_dirty_time, &wb->b_io, |
| 1081 | EXPIRE_DIRTY_ATIME, work); |
Tejun Heo | d6c10f1 | 2015-05-22 17:13:45 -0400 | [diff] [blame] | 1082 | if (moved) |
| 1083 | wb_io_lists_populated(wb); |
Curt Wohlgemuth | ad4e38d | 2011-10-07 21:51:56 -0600 | [diff] [blame] | 1084 | trace_writeback_queue_io(wb, work, moved); |
Jens Axboe | 66f3b8e | 2009-09-02 09:19:46 +0200 | [diff] [blame] | 1085 | } |
| 1086 | |
Christoph Hellwig | a9185b4 | 2010-03-05 09:21:37 +0100 | [diff] [blame] | 1087 | static int write_inode(struct inode *inode, struct writeback_control *wbc) |
Jens Axboe | 66f3b8e | 2009-09-02 09:19:46 +0200 | [diff] [blame] | 1088 | { |
Tejun Heo | 9fb0a7d | 2013-01-11 13:06:37 -0800 | [diff] [blame] | 1089 | int ret; |
| 1090 | |
| 1091 | if (inode->i_sb->s_op->write_inode && !is_bad_inode(inode)) { |
| 1092 | trace_writeback_write_inode_start(inode, wbc); |
| 1093 | ret = inode->i_sb->s_op->write_inode(inode, wbc); |
| 1094 | trace_writeback_write_inode(inode, wbc); |
| 1095 | return ret; |
| 1096 | } |
Jens Axboe | 03ba378 | 2009-09-09 09:08:54 +0200 | [diff] [blame] | 1097 | return 0; |
Fengguang Wu | 2c13657 | 2007-10-16 23:30:39 -0700 | [diff] [blame] | 1098 | } |
| 1099 | |
| 1100 | /* |
Jan Kara | 169ebd9 | 2012-05-03 14:48:03 +0200 | [diff] [blame] | 1101 | * Wait for writeback on an inode to complete. Called with i_lock held. |
| 1102 | * Caller must make sure inode cannot go away when we drop i_lock. |
Christoph Hellwig | 01c0319 | 2009-06-08 13:35:40 +0200 | [diff] [blame] | 1103 | */ |
Jan Kara | 169ebd9 | 2012-05-03 14:48:03 +0200 | [diff] [blame] | 1104 | static void __inode_wait_for_writeback(struct inode *inode) |
| 1105 | __releases(inode->i_lock) |
| 1106 | __acquires(inode->i_lock) |
Christoph Hellwig | 01c0319 | 2009-06-08 13:35:40 +0200 | [diff] [blame] | 1107 | { |
| 1108 | DEFINE_WAIT_BIT(wq, &inode->i_state, __I_SYNC); |
| 1109 | wait_queue_head_t *wqh; |
| 1110 | |
| 1111 | wqh = bit_waitqueue(&inode->i_state, __I_SYNC); |
Dave Chinner | 250df6e | 2011-03-22 22:23:36 +1100 | [diff] [blame] | 1112 | while (inode->i_state & I_SYNC) { |
| 1113 | spin_unlock(&inode->i_lock); |
NeilBrown | 7431620 | 2014-07-07 15:16:04 +1000 | [diff] [blame] | 1114 | __wait_on_bit(wqh, &wq, bit_wait, |
| 1115 | TASK_UNINTERRUPTIBLE); |
Dave Chinner | 250df6e | 2011-03-22 22:23:36 +1100 | [diff] [blame] | 1116 | spin_lock(&inode->i_lock); |
Richard Kennedy | 58a9d3d8 | 2010-05-24 14:32:38 -0700 | [diff] [blame] | 1117 | } |
Christoph Hellwig | 01c0319 | 2009-06-08 13:35:40 +0200 | [diff] [blame] | 1118 | } |
| 1119 | |
| 1120 | /* |
Jan Kara | 169ebd9 | 2012-05-03 14:48:03 +0200 | [diff] [blame] | 1121 | * Wait for writeback on an inode to complete. Caller must have inode pinned. |
| 1122 | */ |
| 1123 | void inode_wait_for_writeback(struct inode *inode) |
| 1124 | { |
| 1125 | spin_lock(&inode->i_lock); |
| 1126 | __inode_wait_for_writeback(inode); |
| 1127 | spin_unlock(&inode->i_lock); |
| 1128 | } |
| 1129 | |
| 1130 | /* |
| 1131 | * Sleep until I_SYNC is cleared. This function must be called with i_lock |
| 1132 | * held and drops it. It is aimed for callers not holding any inode reference |
| 1133 | * so once i_lock is dropped, inode can go away. |
| 1134 | */ |
| 1135 | static void inode_sleep_on_writeback(struct inode *inode) |
| 1136 | __releases(inode->i_lock) |
| 1137 | { |
| 1138 | DEFINE_WAIT(wait); |
| 1139 | wait_queue_head_t *wqh = bit_waitqueue(&inode->i_state, __I_SYNC); |
| 1140 | int sleep; |
| 1141 | |
| 1142 | prepare_to_wait(wqh, &wait, TASK_UNINTERRUPTIBLE); |
| 1143 | sleep = inode->i_state & I_SYNC; |
| 1144 | spin_unlock(&inode->i_lock); |
| 1145 | if (sleep) |
| 1146 | schedule(); |
| 1147 | finish_wait(wqh, &wait); |
| 1148 | } |
| 1149 | |
| 1150 | /* |
Jan Kara | ccb26b5 | 2012-05-03 14:47:58 +0200 | [diff] [blame] | 1151 | * Find proper writeback list for the inode depending on its current state and |
| 1152 | * possibly also change of its state while we were doing writeback. Here we |
| 1153 | * handle things such as livelock prevention or fairness of writeback among |
| 1154 | * inodes. This function can be called only by flusher thread - noone else |
| 1155 | * processes all inodes in writeback lists and requeueing inodes behind flusher |
| 1156 | * thread's back can have unexpected consequences. |
| 1157 | */ |
| 1158 | static void requeue_inode(struct inode *inode, struct bdi_writeback *wb, |
| 1159 | struct writeback_control *wbc) |
| 1160 | { |
| 1161 | if (inode->i_state & I_FREEING) |
| 1162 | return; |
| 1163 | |
| 1164 | /* |
| 1165 | * Sync livelock prevention. Each inode is tagged and synced in one |
| 1166 | * shot. If still dirty, it will be redirty_tail()'ed below. Update |
| 1167 | * the dirty time to prevent enqueue and sync it again. |
| 1168 | */ |
| 1169 | if ((inode->i_state & I_DIRTY) && |
| 1170 | (wbc->sync_mode == WB_SYNC_ALL || wbc->tagged_writepages)) |
| 1171 | inode->dirtied_when = jiffies; |
| 1172 | |
Jan Kara | 4f8ad65 | 2012-05-03 14:48:00 +0200 | [diff] [blame] | 1173 | if (wbc->pages_skipped) { |
| 1174 | /* |
| 1175 | * writeback is not making progress due to locked |
| 1176 | * buffers. Skip this inode for now. |
| 1177 | */ |
| 1178 | redirty_tail(inode, wb); |
| 1179 | return; |
| 1180 | } |
| 1181 | |
Jan Kara | ccb26b5 | 2012-05-03 14:47:58 +0200 | [diff] [blame] | 1182 | if (mapping_tagged(inode->i_mapping, PAGECACHE_TAG_DIRTY)) { |
| 1183 | /* |
| 1184 | * We didn't write back all the pages. nfs_writepages() |
| 1185 | * sometimes bales out without doing anything. |
| 1186 | */ |
| 1187 | if (wbc->nr_to_write <= 0) { |
| 1188 | /* Slice used up. Queue for next turn. */ |
| 1189 | requeue_io(inode, wb); |
| 1190 | } else { |
| 1191 | /* |
| 1192 | * Writeback blocked by something other than |
| 1193 | * congestion. Delay the inode for some time to |
| 1194 | * avoid spinning on the CPU (100% iowait) |
| 1195 | * retrying writeback of the dirty page/inode |
| 1196 | * that cannot be performed immediately. |
| 1197 | */ |
| 1198 | redirty_tail(inode, wb); |
| 1199 | } |
| 1200 | } else if (inode->i_state & I_DIRTY) { |
| 1201 | /* |
| 1202 | * Filesystems can dirty the inode during writeback operations, |
| 1203 | * such as delayed allocation during submission or metadata |
| 1204 | * updates after data IO completion. |
| 1205 | */ |
| 1206 | redirty_tail(inode, wb); |
Theodore Ts'o | 0ae45f6 | 2015-02-02 00:37:00 -0500 | [diff] [blame] | 1207 | } else if (inode->i_state & I_DIRTY_TIME) { |
Theodore Ts'o | a2f4870 | 2015-03-17 12:23:19 -0400 | [diff] [blame] | 1208 | inode->dirtied_when = jiffies; |
Dave Chinner | c7f5408 | 2015-03-04 14:07:22 -0500 | [diff] [blame] | 1209 | inode_io_list_move_locked(inode, wb, &wb->b_dirty_time); |
Jan Kara | ccb26b5 | 2012-05-03 14:47:58 +0200 | [diff] [blame] | 1210 | } else { |
| 1211 | /* The inode is clean. Remove from writeback lists. */ |
Dave Chinner | c7f5408 | 2015-03-04 14:07:22 -0500 | [diff] [blame] | 1212 | inode_io_list_del_locked(inode, wb); |
Jan Kara | ccb26b5 | 2012-05-03 14:47:58 +0200 | [diff] [blame] | 1213 | } |
| 1214 | } |
| 1215 | |
| 1216 | /* |
Jan Kara | 4f8ad65 | 2012-05-03 14:48:00 +0200 | [diff] [blame] | 1217 | * Write out an inode and its dirty pages. Do not update the writeback list |
| 1218 | * linkage. That is left to the caller. The caller is also responsible for |
| 1219 | * setting I_SYNC flag and calling inode_sync_complete() to clear it. |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1220 | */ |
| 1221 | static int |
Yan Hong | cd8ed2a | 2012-10-08 16:33:45 -0700 | [diff] [blame] | 1222 | __writeback_single_inode(struct inode *inode, struct writeback_control *wbc) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1223 | { |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1224 | struct address_space *mapping = inode->i_mapping; |
Wu Fengguang | 251d6a4 | 2010-12-01 17:33:37 -0600 | [diff] [blame] | 1225 | long nr_to_write = wbc->nr_to_write; |
Christoph Hellwig | 01c0319 | 2009-06-08 13:35:40 +0200 | [diff] [blame] | 1226 | unsigned dirty; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1227 | int ret; |
| 1228 | |
Jan Kara | 4f8ad65 | 2012-05-03 14:48:00 +0200 | [diff] [blame] | 1229 | WARN_ON(!(inode->i_state & I_SYNC)); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1230 | |
Tejun Heo | 9fb0a7d | 2013-01-11 13:06:37 -0800 | [diff] [blame] | 1231 | trace_writeback_single_inode_start(inode, wbc, nr_to_write); |
| 1232 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1233 | ret = do_writepages(mapping, wbc); |
| 1234 | |
Christoph Hellwig | 26821ed | 2010-03-05 09:21:21 +0100 | [diff] [blame] | 1235 | /* |
| 1236 | * Make sure to wait on the data before writing out the metadata. |
| 1237 | * This is important for filesystems that modify metadata on data |
Dave Chinner | 7747bd4 | 2013-07-02 22:38:35 +1000 | [diff] [blame] | 1238 | * I/O completion. We don't do it for sync(2) writeback because it has a |
| 1239 | * separate, external IO completion path and ->sync_fs for guaranteeing |
| 1240 | * inode metadata is written back correctly. |
Christoph Hellwig | 26821ed | 2010-03-05 09:21:21 +0100 | [diff] [blame] | 1241 | */ |
Dave Chinner | 7747bd4 | 2013-07-02 22:38:35 +1000 | [diff] [blame] | 1242 | if (wbc->sync_mode == WB_SYNC_ALL && !wbc->for_sync) { |
Christoph Hellwig | 26821ed | 2010-03-05 09:21:21 +0100 | [diff] [blame] | 1243 | int err = filemap_fdatawait(mapping); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1244 | if (ret == 0) |
| 1245 | ret = err; |
| 1246 | } |
| 1247 | |
Dmitry Monakhov | 5547e8a | 2010-05-07 13:35:44 +0400 | [diff] [blame] | 1248 | /* |
| 1249 | * Some filesystems may redirty the inode during the writeback |
| 1250 | * due to delalloc, clear dirty metadata flags right before |
| 1251 | * write_inode() |
| 1252 | */ |
Dave Chinner | 250df6e | 2011-03-22 22:23:36 +1100 | [diff] [blame] | 1253 | spin_lock(&inode->i_lock); |
Tejun Heo | 9c6ac78 | 2014-10-24 15:38:21 -0400 | [diff] [blame] | 1254 | |
Dmitry Monakhov | 5547e8a | 2010-05-07 13:35:44 +0400 | [diff] [blame] | 1255 | dirty = inode->i_state & I_DIRTY; |
Theodore Ts'o | a2f4870 | 2015-03-17 12:23:19 -0400 | [diff] [blame] | 1256 | if (inode->i_state & I_DIRTY_TIME) { |
| 1257 | if ((dirty & (I_DIRTY_SYNC | I_DIRTY_DATASYNC)) || |
| 1258 | unlikely(inode->i_state & I_DIRTY_TIME_EXPIRED) || |
| 1259 | unlikely(time_after(jiffies, |
| 1260 | (inode->dirtied_time_when + |
| 1261 | dirtytime_expire_interval * HZ)))) { |
| 1262 | dirty |= I_DIRTY_TIME | I_DIRTY_TIME_EXPIRED; |
| 1263 | trace_writeback_lazytime(inode); |
| 1264 | } |
| 1265 | } else |
| 1266 | inode->i_state &= ~I_DIRTY_TIME_EXPIRED; |
Theodore Ts'o | 0ae45f6 | 2015-02-02 00:37:00 -0500 | [diff] [blame] | 1267 | inode->i_state &= ~dirty; |
Tejun Heo | 9c6ac78 | 2014-10-24 15:38:21 -0400 | [diff] [blame] | 1268 | |
| 1269 | /* |
| 1270 | * Paired with smp_mb() in __mark_inode_dirty(). This allows |
| 1271 | * __mark_inode_dirty() to test i_state without grabbing i_lock - |
| 1272 | * either they see the I_DIRTY bits cleared or we see the dirtied |
| 1273 | * inode. |
| 1274 | * |
| 1275 | * I_DIRTY_PAGES is always cleared together above even if @mapping |
| 1276 | * still has dirty pages. The flag is reinstated after smp_mb() if |
| 1277 | * necessary. This guarantees that either __mark_inode_dirty() |
| 1278 | * sees clear I_DIRTY_PAGES or we see PAGECACHE_TAG_DIRTY. |
| 1279 | */ |
| 1280 | smp_mb(); |
| 1281 | |
| 1282 | if (mapping_tagged(mapping, PAGECACHE_TAG_DIRTY)) |
| 1283 | inode->i_state |= I_DIRTY_PAGES; |
| 1284 | |
Dave Chinner | 250df6e | 2011-03-22 22:23:36 +1100 | [diff] [blame] | 1285 | spin_unlock(&inode->i_lock); |
Tejun Heo | 9c6ac78 | 2014-10-24 15:38:21 -0400 | [diff] [blame] | 1286 | |
Theodore Ts'o | 0ae45f6 | 2015-02-02 00:37:00 -0500 | [diff] [blame] | 1287 | if (dirty & I_DIRTY_TIME) |
| 1288 | mark_inode_dirty_sync(inode); |
Christoph Hellwig | 26821ed | 2010-03-05 09:21:21 +0100 | [diff] [blame] | 1289 | /* Don't write the inode if only I_DIRTY_PAGES was set */ |
Theodore Ts'o | 0ae45f6 | 2015-02-02 00:37:00 -0500 | [diff] [blame] | 1290 | if (dirty & ~I_DIRTY_PAGES) { |
Christoph Hellwig | a9185b4 | 2010-03-05 09:21:37 +0100 | [diff] [blame] | 1291 | int err = write_inode(inode, wbc); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1292 | if (ret == 0) |
| 1293 | ret = err; |
| 1294 | } |
Jan Kara | 4f8ad65 | 2012-05-03 14:48:00 +0200 | [diff] [blame] | 1295 | trace_writeback_single_inode(inode, wbc, nr_to_write); |
| 1296 | return ret; |
| 1297 | } |
| 1298 | |
| 1299 | /* |
| 1300 | * Write out an inode's dirty pages. Either the caller has an active reference |
| 1301 | * on the inode or the inode has I_WILL_FREE set. |
| 1302 | * |
| 1303 | * This function is designed to be called for writing back one inode which |
| 1304 | * we go e.g. from filesystem. Flusher thread uses __writeback_single_inode() |
| 1305 | * and does more profound writeback list handling in writeback_sb_inodes(). |
| 1306 | */ |
| 1307 | static int |
| 1308 | writeback_single_inode(struct inode *inode, struct bdi_writeback *wb, |
| 1309 | struct writeback_control *wbc) |
| 1310 | { |
| 1311 | int ret = 0; |
| 1312 | |
| 1313 | spin_lock(&inode->i_lock); |
| 1314 | if (!atomic_read(&inode->i_count)) |
| 1315 | WARN_ON(!(inode->i_state & (I_WILL_FREE|I_FREEING))); |
| 1316 | else |
| 1317 | WARN_ON(inode->i_state & I_WILL_FREE); |
| 1318 | |
| 1319 | if (inode->i_state & I_SYNC) { |
| 1320 | if (wbc->sync_mode != WB_SYNC_ALL) |
| 1321 | goto out; |
| 1322 | /* |
Jan Kara | 169ebd9 | 2012-05-03 14:48:03 +0200 | [diff] [blame] | 1323 | * It's a data-integrity sync. We must wait. Since callers hold |
| 1324 | * inode reference or inode has I_WILL_FREE set, it cannot go |
| 1325 | * away under us. |
Jan Kara | 4f8ad65 | 2012-05-03 14:48:00 +0200 | [diff] [blame] | 1326 | */ |
Jan Kara | 169ebd9 | 2012-05-03 14:48:03 +0200 | [diff] [blame] | 1327 | __inode_wait_for_writeback(inode); |
Jan Kara | 4f8ad65 | 2012-05-03 14:48:00 +0200 | [diff] [blame] | 1328 | } |
| 1329 | WARN_ON(inode->i_state & I_SYNC); |
| 1330 | /* |
Jan Kara | f9b0e05 | 2013-12-14 04:21:26 +0800 | [diff] [blame] | 1331 | * Skip inode if it is clean and we have no outstanding writeback in |
| 1332 | * WB_SYNC_ALL mode. We don't want to mess with writeback lists in this |
| 1333 | * function since flusher thread may be doing for example sync in |
| 1334 | * parallel and if we move the inode, it could get skipped. So here we |
| 1335 | * make sure inode is on some writeback list and leave it there unless |
| 1336 | * we have completely cleaned the inode. |
Jan Kara | 4f8ad65 | 2012-05-03 14:48:00 +0200 | [diff] [blame] | 1337 | */ |
Theodore Ts'o | 0ae45f6 | 2015-02-02 00:37:00 -0500 | [diff] [blame] | 1338 | if (!(inode->i_state & I_DIRTY_ALL) && |
Jan Kara | f9b0e05 | 2013-12-14 04:21:26 +0800 | [diff] [blame] | 1339 | (wbc->sync_mode != WB_SYNC_ALL || |
| 1340 | !mapping_tagged(inode->i_mapping, PAGECACHE_TAG_WRITEBACK))) |
Jan Kara | 4f8ad65 | 2012-05-03 14:48:00 +0200 | [diff] [blame] | 1341 | goto out; |
| 1342 | inode->i_state |= I_SYNC; |
Tejun Heo | b16b1de | 2015-06-02 08:39:48 -0600 | [diff] [blame] | 1343 | wbc_attach_and_unlock_inode(wbc, inode); |
Jan Kara | 4f8ad65 | 2012-05-03 14:48:00 +0200 | [diff] [blame] | 1344 | |
Yan Hong | cd8ed2a | 2012-10-08 16:33:45 -0700 | [diff] [blame] | 1345 | ret = __writeback_single_inode(inode, wbc); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1346 | |
Tejun Heo | b16b1de | 2015-06-02 08:39:48 -0600 | [diff] [blame] | 1347 | wbc_detach_inode(wbc); |
Christoph Hellwig | f758eea | 2011-04-21 18:19:44 -0600 | [diff] [blame] | 1348 | spin_lock(&wb->list_lock); |
Dave Chinner | 250df6e | 2011-03-22 22:23:36 +1100 | [diff] [blame] | 1349 | spin_lock(&inode->i_lock); |
Jan Kara | 4f8ad65 | 2012-05-03 14:48:00 +0200 | [diff] [blame] | 1350 | /* |
| 1351 | * If inode is clean, remove it from writeback lists. Otherwise don't |
| 1352 | * touch it. See comment above for explanation. |
| 1353 | */ |
Theodore Ts'o | 0ae45f6 | 2015-02-02 00:37:00 -0500 | [diff] [blame] | 1354 | if (!(inode->i_state & I_DIRTY_ALL)) |
Dave Chinner | c7f5408 | 2015-03-04 14:07:22 -0500 | [diff] [blame] | 1355 | inode_io_list_del_locked(inode, wb); |
Jan Kara | 4f8ad65 | 2012-05-03 14:48:00 +0200 | [diff] [blame] | 1356 | spin_unlock(&wb->list_lock); |
Joern Engel | 1c0eeaf | 2007-10-16 23:30:44 -0700 | [diff] [blame] | 1357 | inode_sync_complete(inode); |
Jan Kara | 4f8ad65 | 2012-05-03 14:48:00 +0200 | [diff] [blame] | 1358 | out: |
| 1359 | spin_unlock(&inode->i_lock); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1360 | return ret; |
| 1361 | } |
| 1362 | |
Tejun Heo | a88a341 | 2015-05-22 17:13:28 -0400 | [diff] [blame] | 1363 | static long writeback_chunk_size(struct bdi_writeback *wb, |
Wu Fengguang | 1a12d8b | 2010-08-29 13:28:09 -0600 | [diff] [blame] | 1364 | struct wb_writeback_work *work) |
Wu Fengguang | d46db3d | 2011-05-04 19:54:37 -0600 | [diff] [blame] | 1365 | { |
| 1366 | long pages; |
| 1367 | |
| 1368 | /* |
| 1369 | * WB_SYNC_ALL mode does livelock avoidance by syncing dirty |
| 1370 | * inodes/pages in one big loop. Setting wbc.nr_to_write=LONG_MAX |
| 1371 | * here avoids calling into writeback_inodes_wb() more than once. |
| 1372 | * |
| 1373 | * The intended call sequence for WB_SYNC_ALL writeback is: |
| 1374 | * |
| 1375 | * wb_writeback() |
| 1376 | * writeback_sb_inodes() <== called only once |
| 1377 | * write_cache_pages() <== called once for each inode |
| 1378 | * (quickly) tag currently dirty pages |
| 1379 | * (maybe slowly) sync all tagged pages |
| 1380 | */ |
| 1381 | if (work->sync_mode == WB_SYNC_ALL || work->tagged_writepages) |
| 1382 | pages = LONG_MAX; |
Wu Fengguang | 1a12d8b | 2010-08-29 13:28:09 -0600 | [diff] [blame] | 1383 | else { |
Tejun Heo | a88a341 | 2015-05-22 17:13:28 -0400 | [diff] [blame] | 1384 | pages = min(wb->avg_write_bandwidth / 2, |
Tejun Heo | dcc25ae | 2015-05-22 18:23:22 -0400 | [diff] [blame] | 1385 | global_wb_domain.dirty_limit / DIRTY_SCOPE); |
Wu Fengguang | 1a12d8b | 2010-08-29 13:28:09 -0600 | [diff] [blame] | 1386 | pages = min(pages, work->nr_pages); |
| 1387 | pages = round_down(pages + MIN_WRITEBACK_PAGES, |
| 1388 | MIN_WRITEBACK_PAGES); |
| 1389 | } |
Wu Fengguang | d46db3d | 2011-05-04 19:54:37 -0600 | [diff] [blame] | 1390 | |
| 1391 | return pages; |
| 1392 | } |
| 1393 | |
Jens Axboe | 03ba378 | 2009-09-09 09:08:54 +0200 | [diff] [blame] | 1394 | /* |
Edward Shishkin | f11c9c5 | 2010-03-11 14:09:47 -0800 | [diff] [blame] | 1395 | * Write a portion of b_io inodes which belong to @sb. |
Christoph Hellwig | edadfb1 | 2010-06-10 12:07:54 +0200 | [diff] [blame] | 1396 | * |
Wu Fengguang | d46db3d | 2011-05-04 19:54:37 -0600 | [diff] [blame] | 1397 | * Return the number of pages and/or inodes written. |
Linus Torvalds | 0ba13fd | 2015-09-11 13:26:39 -0700 | [diff] [blame] | 1398 | * |
| 1399 | * NOTE! This is called with wb->list_lock held, and will |
| 1400 | * unlock and relock that for each inode it ends up doing |
| 1401 | * IO for. |
Edward Shishkin | f11c9c5 | 2010-03-11 14:09:47 -0800 | [diff] [blame] | 1402 | */ |
Wu Fengguang | d46db3d | 2011-05-04 19:54:37 -0600 | [diff] [blame] | 1403 | static long writeback_sb_inodes(struct super_block *sb, |
| 1404 | struct bdi_writeback *wb, |
| 1405 | struct wb_writeback_work *work) |
Jens Axboe | 03ba378 | 2009-09-09 09:08:54 +0200 | [diff] [blame] | 1406 | { |
Wu Fengguang | d46db3d | 2011-05-04 19:54:37 -0600 | [diff] [blame] | 1407 | struct writeback_control wbc = { |
| 1408 | .sync_mode = work->sync_mode, |
| 1409 | .tagged_writepages = work->tagged_writepages, |
| 1410 | .for_kupdate = work->for_kupdate, |
| 1411 | .for_background = work->for_background, |
Dave Chinner | 7747bd4 | 2013-07-02 22:38:35 +1000 | [diff] [blame] | 1412 | .for_sync = work->for_sync, |
Wu Fengguang | d46db3d | 2011-05-04 19:54:37 -0600 | [diff] [blame] | 1413 | .range_cyclic = work->range_cyclic, |
| 1414 | .range_start = 0, |
| 1415 | .range_end = LLONG_MAX, |
| 1416 | }; |
| 1417 | unsigned long start_time = jiffies; |
| 1418 | long write_chunk; |
| 1419 | long wrote = 0; /* count both pages and inodes */ |
| 1420 | |
Jens Axboe | 03ba378 | 2009-09-09 09:08:54 +0200 | [diff] [blame] | 1421 | while (!list_empty(&wb->b_io)) { |
Nick Piggin | 7ccf19a | 2010-10-21 11:49:30 +1100 | [diff] [blame] | 1422 | struct inode *inode = wb_inode(wb->b_io.prev); |
Christoph Hellwig | edadfb1 | 2010-06-10 12:07:54 +0200 | [diff] [blame] | 1423 | |
| 1424 | if (inode->i_sb != sb) { |
Wu Fengguang | d46db3d | 2011-05-04 19:54:37 -0600 | [diff] [blame] | 1425 | if (work->sb) { |
Christoph Hellwig | edadfb1 | 2010-06-10 12:07:54 +0200 | [diff] [blame] | 1426 | /* |
| 1427 | * We only want to write back data for this |
| 1428 | * superblock, move all inodes not belonging |
| 1429 | * to it back onto the dirty list. |
| 1430 | */ |
Christoph Hellwig | f758eea | 2011-04-21 18:19:44 -0600 | [diff] [blame] | 1431 | redirty_tail(inode, wb); |
Christoph Hellwig | edadfb1 | 2010-06-10 12:07:54 +0200 | [diff] [blame] | 1432 | continue; |
| 1433 | } |
| 1434 | |
| 1435 | /* |
| 1436 | * The inode belongs to a different superblock. |
| 1437 | * Bounce back to the caller to unpin this and |
| 1438 | * pin the next superblock. |
| 1439 | */ |
Wu Fengguang | d46db3d | 2011-05-04 19:54:37 -0600 | [diff] [blame] | 1440 | break; |
Christoph Hellwig | edadfb1 | 2010-06-10 12:07:54 +0200 | [diff] [blame] | 1441 | } |
| 1442 | |
Christoph Hellwig | 9843b76 | 2010-10-24 19:40:46 +0200 | [diff] [blame] | 1443 | /* |
Wanpeng Li | 331cbde | 2012-06-09 11:10:55 +0800 | [diff] [blame] | 1444 | * Don't bother with new inodes or inodes being freed, first |
| 1445 | * kind does not need periodic writeout yet, and for the latter |
Christoph Hellwig | 9843b76 | 2010-10-24 19:40:46 +0200 | [diff] [blame] | 1446 | * kind writeout is handled by the freer. |
| 1447 | */ |
Dave Chinner | 250df6e | 2011-03-22 22:23:36 +1100 | [diff] [blame] | 1448 | spin_lock(&inode->i_lock); |
Christoph Hellwig | 9843b76 | 2010-10-24 19:40:46 +0200 | [diff] [blame] | 1449 | if (inode->i_state & (I_NEW | I_FREEING | I_WILL_FREE)) { |
Dave Chinner | 250df6e | 2011-03-22 22:23:36 +1100 | [diff] [blame] | 1450 | spin_unlock(&inode->i_lock); |
Wu Fengguang | fcc5c22 | 2011-07-11 23:08:50 -0700 | [diff] [blame] | 1451 | redirty_tail(inode, wb); |
Nick Piggin | 7ef0d73 | 2009-03-12 14:31:38 -0700 | [diff] [blame] | 1452 | continue; |
| 1453 | } |
Jan Kara | cc1676d | 2012-05-03 14:47:56 +0200 | [diff] [blame] | 1454 | if ((inode->i_state & I_SYNC) && wbc.sync_mode != WB_SYNC_ALL) { |
| 1455 | /* |
| 1456 | * If this inode is locked for writeback and we are not |
| 1457 | * doing writeback-for-data-integrity, move it to |
| 1458 | * b_more_io so that writeback can proceed with the |
| 1459 | * other inodes on s_io. |
| 1460 | * |
| 1461 | * We'll have another go at writing back this inode |
| 1462 | * when we completed a full scan of b_io. |
| 1463 | */ |
| 1464 | spin_unlock(&inode->i_lock); |
| 1465 | requeue_io(inode, wb); |
| 1466 | trace_writeback_sb_inodes_requeue(inode); |
| 1467 | continue; |
| 1468 | } |
Jan Kara | f0d07b7 | 2012-05-03 14:47:59 +0200 | [diff] [blame] | 1469 | spin_unlock(&wb->list_lock); |
| 1470 | |
Jan Kara | 4f8ad65 | 2012-05-03 14:48:00 +0200 | [diff] [blame] | 1471 | /* |
| 1472 | * We already requeued the inode if it had I_SYNC set and we |
| 1473 | * are doing WB_SYNC_NONE writeback. So this catches only the |
| 1474 | * WB_SYNC_ALL case. |
| 1475 | */ |
Jan Kara | 169ebd9 | 2012-05-03 14:48:03 +0200 | [diff] [blame] | 1476 | if (inode->i_state & I_SYNC) { |
| 1477 | /* Wait for I_SYNC. This function drops i_lock... */ |
| 1478 | inode_sleep_on_writeback(inode); |
| 1479 | /* Inode may be gone, start again */ |
Jan Kara | ead188f | 2012-06-08 17:07:36 +0200 | [diff] [blame] | 1480 | spin_lock(&wb->list_lock); |
Jan Kara | 169ebd9 | 2012-05-03 14:48:03 +0200 | [diff] [blame] | 1481 | continue; |
| 1482 | } |
Jan Kara | 4f8ad65 | 2012-05-03 14:48:00 +0200 | [diff] [blame] | 1483 | inode->i_state |= I_SYNC; |
Tejun Heo | b16b1de | 2015-06-02 08:39:48 -0600 | [diff] [blame] | 1484 | wbc_attach_and_unlock_inode(&wbc, inode); |
Jan Kara | 169ebd9 | 2012-05-03 14:48:03 +0200 | [diff] [blame] | 1485 | |
Tejun Heo | a88a341 | 2015-05-22 17:13:28 -0400 | [diff] [blame] | 1486 | write_chunk = writeback_chunk_size(wb, work); |
Wu Fengguang | d46db3d | 2011-05-04 19:54:37 -0600 | [diff] [blame] | 1487 | wbc.nr_to_write = write_chunk; |
| 1488 | wbc.pages_skipped = 0; |
Dave Chinner | 250df6e | 2011-03-22 22:23:36 +1100 | [diff] [blame] | 1489 | |
Jan Kara | 169ebd9 | 2012-05-03 14:48:03 +0200 | [diff] [blame] | 1490 | /* |
| 1491 | * We use I_SYNC to pin the inode in memory. While it is set |
| 1492 | * evict_inode() will wait so the inode cannot be freed. |
| 1493 | */ |
Yan Hong | cd8ed2a | 2012-10-08 16:33:45 -0700 | [diff] [blame] | 1494 | __writeback_single_inode(inode, &wbc); |
Wu Fengguang | d46db3d | 2011-05-04 19:54:37 -0600 | [diff] [blame] | 1495 | |
Tejun Heo | b16b1de | 2015-06-02 08:39:48 -0600 | [diff] [blame] | 1496 | wbc_detach_inode(&wbc); |
Wu Fengguang | d46db3d | 2011-05-04 19:54:37 -0600 | [diff] [blame] | 1497 | work->nr_pages -= write_chunk - wbc.nr_to_write; |
| 1498 | wrote += write_chunk - wbc.nr_to_write; |
Chris Mason | 590dca3 | 2015-09-18 13:35:08 -0400 | [diff] [blame] | 1499 | |
| 1500 | if (need_resched()) { |
| 1501 | /* |
| 1502 | * We're trying to balance between building up a nice |
| 1503 | * long list of IOs to improve our merge rate, and |
| 1504 | * getting those IOs out quickly for anyone throttling |
| 1505 | * in balance_dirty_pages(). cond_resched() doesn't |
| 1506 | * unplug, so get our IOs out the door before we |
| 1507 | * give up the CPU. |
| 1508 | */ |
| 1509 | blk_flush_plug(current); |
| 1510 | cond_resched(); |
| 1511 | } |
| 1512 | |
| 1513 | |
Jan Kara | 4f8ad65 | 2012-05-03 14:48:00 +0200 | [diff] [blame] | 1514 | spin_lock(&wb->list_lock); |
| 1515 | spin_lock(&inode->i_lock); |
Theodore Ts'o | 0ae45f6 | 2015-02-02 00:37:00 -0500 | [diff] [blame] | 1516 | if (!(inode->i_state & I_DIRTY_ALL)) |
Wu Fengguang | d46db3d | 2011-05-04 19:54:37 -0600 | [diff] [blame] | 1517 | wrote++; |
Jan Kara | 4f8ad65 | 2012-05-03 14:48:00 +0200 | [diff] [blame] | 1518 | requeue_inode(inode, wb, &wbc); |
| 1519 | inode_sync_complete(inode); |
Dave Chinner | 0f1b1fd | 2011-03-22 22:23:43 +1100 | [diff] [blame] | 1520 | spin_unlock(&inode->i_lock); |
Chris Mason | 590dca3 | 2015-09-18 13:35:08 -0400 | [diff] [blame] | 1521 | |
Wu Fengguang | d46db3d | 2011-05-04 19:54:37 -0600 | [diff] [blame] | 1522 | /* |
| 1523 | * bail out to wb_writeback() often enough to check |
| 1524 | * background threshold and other termination conditions. |
| 1525 | */ |
| 1526 | if (wrote) { |
| 1527 | if (time_is_before_jiffies(start_time + HZ / 10UL)) |
| 1528 | break; |
| 1529 | if (work->nr_pages <= 0) |
| 1530 | break; |
Fengguang Wu | 8bc3be2 | 2008-02-04 22:29:36 -0800 | [diff] [blame] | 1531 | } |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1532 | } |
Wu Fengguang | d46db3d | 2011-05-04 19:54:37 -0600 | [diff] [blame] | 1533 | return wrote; |
Edward Shishkin | f11c9c5 | 2010-03-11 14:09:47 -0800 | [diff] [blame] | 1534 | } |
Nick Piggin | 38f2197 | 2009-01-06 14:40:25 -0800 | [diff] [blame] | 1535 | |
Wu Fengguang | d46db3d | 2011-05-04 19:54:37 -0600 | [diff] [blame] | 1536 | static long __writeback_inodes_wb(struct bdi_writeback *wb, |
| 1537 | struct wb_writeback_work *work) |
Edward Shishkin | f11c9c5 | 2010-03-11 14:09:47 -0800 | [diff] [blame] | 1538 | { |
Wu Fengguang | d46db3d | 2011-05-04 19:54:37 -0600 | [diff] [blame] | 1539 | unsigned long start_time = jiffies; |
| 1540 | long wrote = 0; |
Edward Shishkin | f11c9c5 | 2010-03-11 14:09:47 -0800 | [diff] [blame] | 1541 | |
| 1542 | while (!list_empty(&wb->b_io)) { |
Nick Piggin | 7ccf19a | 2010-10-21 11:49:30 +1100 | [diff] [blame] | 1543 | struct inode *inode = wb_inode(wb->b_io.prev); |
Edward Shishkin | f11c9c5 | 2010-03-11 14:09:47 -0800 | [diff] [blame] | 1544 | struct super_block *sb = inode->i_sb; |
Edward Shishkin | f11c9c5 | 2010-03-11 14:09:47 -0800 | [diff] [blame] | 1545 | |
Konstantin Khlebnikov | eb6ef3d | 2015-02-19 20:19:35 +0300 | [diff] [blame] | 1546 | if (!trylock_super(sb)) { |
Wu Fengguang | 0e99581 | 2011-07-29 22:14:35 -0600 | [diff] [blame] | 1547 | /* |
Konstantin Khlebnikov | eb6ef3d | 2015-02-19 20:19:35 +0300 | [diff] [blame] | 1548 | * trylock_super() may fail consistently due to |
Wu Fengguang | 0e99581 | 2011-07-29 22:14:35 -0600 | [diff] [blame] | 1549 | * s_umount being grabbed by someone else. Don't use |
| 1550 | * requeue_io() to avoid busy retrying the inode/sb. |
| 1551 | */ |
| 1552 | redirty_tail(inode, wb); |
Christoph Hellwig | edadfb1 | 2010-06-10 12:07:54 +0200 | [diff] [blame] | 1553 | continue; |
Edward Shishkin | f11c9c5 | 2010-03-11 14:09:47 -0800 | [diff] [blame] | 1554 | } |
Wu Fengguang | d46db3d | 2011-05-04 19:54:37 -0600 | [diff] [blame] | 1555 | wrote += writeback_sb_inodes(sb, wb, work); |
Konstantin Khlebnikov | eb6ef3d | 2015-02-19 20:19:35 +0300 | [diff] [blame] | 1556 | up_read(&sb->s_umount); |
Edward Shishkin | f11c9c5 | 2010-03-11 14:09:47 -0800 | [diff] [blame] | 1557 | |
Wu Fengguang | d46db3d | 2011-05-04 19:54:37 -0600 | [diff] [blame] | 1558 | /* refer to the same tests at the end of writeback_sb_inodes */ |
| 1559 | if (wrote) { |
| 1560 | if (time_is_before_jiffies(start_time + HZ / 10UL)) |
| 1561 | break; |
| 1562 | if (work->nr_pages <= 0) |
| 1563 | break; |
| 1564 | } |
Edward Shishkin | f11c9c5 | 2010-03-11 14:09:47 -0800 | [diff] [blame] | 1565 | } |
Jens Axboe | 66f3b8e | 2009-09-02 09:19:46 +0200 | [diff] [blame] | 1566 | /* Leave any unwritten inodes on b_io */ |
Wu Fengguang | d46db3d | 2011-05-04 19:54:37 -0600 | [diff] [blame] | 1567 | return wrote; |
Jens Axboe | 66f3b8e | 2009-09-02 09:19:46 +0200 | [diff] [blame] | 1568 | } |
| 1569 | |
Wanpeng Li | 7d9f073 | 2013-09-11 14:22:40 -0700 | [diff] [blame] | 1570 | static long writeback_inodes_wb(struct bdi_writeback *wb, long nr_pages, |
Curt Wohlgemuth | 0e175a1 | 2011-10-07 21:54:10 -0600 | [diff] [blame] | 1571 | enum wb_reason reason) |
Christoph Hellwig | edadfb1 | 2010-06-10 12:07:54 +0200 | [diff] [blame] | 1572 | { |
Wu Fengguang | d46db3d | 2011-05-04 19:54:37 -0600 | [diff] [blame] | 1573 | struct wb_writeback_work work = { |
| 1574 | .nr_pages = nr_pages, |
| 1575 | .sync_mode = WB_SYNC_NONE, |
| 1576 | .range_cyclic = 1, |
Curt Wohlgemuth | 0e175a1 | 2011-10-07 21:54:10 -0600 | [diff] [blame] | 1577 | .reason = reason, |
Wu Fengguang | d46db3d | 2011-05-04 19:54:37 -0600 | [diff] [blame] | 1578 | }; |
Linus Torvalds | 505a666 | 2015-09-11 13:37:19 -0700 | [diff] [blame] | 1579 | struct blk_plug plug; |
Christoph Hellwig | edadfb1 | 2010-06-10 12:07:54 +0200 | [diff] [blame] | 1580 | |
Linus Torvalds | 505a666 | 2015-09-11 13:37:19 -0700 | [diff] [blame] | 1581 | blk_start_plug(&plug); |
Christoph Hellwig | f758eea | 2011-04-21 18:19:44 -0600 | [diff] [blame] | 1582 | spin_lock(&wb->list_lock); |
Wu Fengguang | 424b351 | 2010-07-21 20:11:53 -0600 | [diff] [blame] | 1583 | if (list_empty(&wb->b_io)) |
Curt Wohlgemuth | ad4e38d | 2011-10-07 21:51:56 -0600 | [diff] [blame] | 1584 | queue_io(wb, &work); |
Wu Fengguang | d46db3d | 2011-05-04 19:54:37 -0600 | [diff] [blame] | 1585 | __writeback_inodes_wb(wb, &work); |
Christoph Hellwig | f758eea | 2011-04-21 18:19:44 -0600 | [diff] [blame] | 1586 | spin_unlock(&wb->list_lock); |
Linus Torvalds | 505a666 | 2015-09-11 13:37:19 -0700 | [diff] [blame] | 1587 | blk_finish_plug(&plug); |
Christoph Hellwig | edadfb1 | 2010-06-10 12:07:54 +0200 | [diff] [blame] | 1588 | |
Wu Fengguang | d46db3d | 2011-05-04 19:54:37 -0600 | [diff] [blame] | 1589 | return nr_pages - work.nr_pages; |
Jens Axboe | 66f3b8e | 2009-09-02 09:19:46 +0200 | [diff] [blame] | 1590 | } |
| 1591 | |
Jens Axboe | 03ba378 | 2009-09-09 09:08:54 +0200 | [diff] [blame] | 1592 | /* |
| 1593 | * Explicit flushing or periodic writeback of "old" data. |
| 1594 | * |
| 1595 | * Define "old": the first time one of an inode's pages is dirtied, we mark the |
| 1596 | * dirtying-time in the inode's address_space. So this periodic writeback code |
| 1597 | * just walks the superblock inode list, writing back any inodes which are |
| 1598 | * older than a specific point in time. |
| 1599 | * |
| 1600 | * Try to run once per dirty_writeback_interval. But if a writeback event |
| 1601 | * takes longer than a dirty_writeback_interval interval, then leave a |
| 1602 | * one-second gap. |
| 1603 | * |
| 1604 | * older_than_this takes precedence over nr_to_write. So we'll only write back |
| 1605 | * all dirty pages if they are all attached to "old" mappings. |
| 1606 | */ |
Jens Axboe | c4a77a6 | 2009-09-16 15:18:25 +0200 | [diff] [blame] | 1607 | static long wb_writeback(struct bdi_writeback *wb, |
Christoph Hellwig | 83ba7b0 | 2010-07-06 08:59:53 +0200 | [diff] [blame] | 1608 | struct wb_writeback_work *work) |
Jens Axboe | 03ba378 | 2009-09-09 09:08:54 +0200 | [diff] [blame] | 1609 | { |
Wu Fengguang | e98be2d | 2010-08-29 11:22:30 -0600 | [diff] [blame] | 1610 | unsigned long wb_start = jiffies; |
Wu Fengguang | d46db3d | 2011-05-04 19:54:37 -0600 | [diff] [blame] | 1611 | long nr_pages = work->nr_pages; |
Jan Kara | 0dc83bd | 2014-02-21 11:19:04 +0100 | [diff] [blame] | 1612 | unsigned long oldest_jif; |
Jan Kara | a5989bd | 2009-09-16 19:22:48 +0200 | [diff] [blame] | 1613 | struct inode *inode; |
Wu Fengguang | d46db3d | 2011-05-04 19:54:37 -0600 | [diff] [blame] | 1614 | long progress; |
Linus Torvalds | 505a666 | 2015-09-11 13:37:19 -0700 | [diff] [blame] | 1615 | struct blk_plug plug; |
Jens Axboe | 03ba378 | 2009-09-09 09:08:54 +0200 | [diff] [blame] | 1616 | |
Jan Kara | 0dc83bd | 2014-02-21 11:19:04 +0100 | [diff] [blame] | 1617 | oldest_jif = jiffies; |
| 1618 | work->older_than_this = &oldest_jif; |
Jens Axboe | 03ba378 | 2009-09-09 09:08:54 +0200 | [diff] [blame] | 1619 | |
Linus Torvalds | 505a666 | 2015-09-11 13:37:19 -0700 | [diff] [blame] | 1620 | blk_start_plug(&plug); |
Wu Fengguang | e8dfc30 | 2011-04-21 12:06:32 -0600 | [diff] [blame] | 1621 | spin_lock(&wb->list_lock); |
Jens Axboe | 03ba378 | 2009-09-09 09:08:54 +0200 | [diff] [blame] | 1622 | for (;;) { |
| 1623 | /* |
Wu Fengguang | d3ddec7 | 2009-09-23 20:33:40 +0800 | [diff] [blame] | 1624 | * Stop writeback when nr_pages has been consumed |
Jens Axboe | 03ba378 | 2009-09-09 09:08:54 +0200 | [diff] [blame] | 1625 | */ |
Christoph Hellwig | 83ba7b0 | 2010-07-06 08:59:53 +0200 | [diff] [blame] | 1626 | if (work->nr_pages <= 0) |
Jens Axboe | 03ba378 | 2009-09-09 09:08:54 +0200 | [diff] [blame] | 1627 | break; |
| 1628 | |
| 1629 | /* |
Jan Kara | aa373cf | 2011-01-13 15:45:47 -0800 | [diff] [blame] | 1630 | * Background writeout and kupdate-style writeback may |
| 1631 | * run forever. Stop them if there is other work to do |
| 1632 | * so that e.g. sync can proceed. They'll be restarted |
| 1633 | * after the other works are all done. |
| 1634 | */ |
| 1635 | if ((work->for_background || work->for_kupdate) && |
Tejun Heo | f0054bb | 2015-05-22 17:13:30 -0400 | [diff] [blame] | 1636 | !list_empty(&wb->work_list)) |
Jan Kara | aa373cf | 2011-01-13 15:45:47 -0800 | [diff] [blame] | 1637 | break; |
| 1638 | |
| 1639 | /* |
Wu Fengguang | d3ddec7 | 2009-09-23 20:33:40 +0800 | [diff] [blame] | 1640 | * For background writeout, stop when we are below the |
| 1641 | * background dirty threshold |
Jens Axboe | 03ba378 | 2009-09-09 09:08:54 +0200 | [diff] [blame] | 1642 | */ |
Tejun Heo | aa661bb | 2015-05-22 18:23:31 -0400 | [diff] [blame] | 1643 | if (work->for_background && !wb_over_bg_thresh(wb)) |
Jens Axboe | 03ba378 | 2009-09-09 09:08:54 +0200 | [diff] [blame] | 1644 | break; |
| 1645 | |
Jan Kara | 1bc36b6 | 2011-10-19 11:44:41 +0200 | [diff] [blame] | 1646 | /* |
| 1647 | * Kupdate and background works are special and we want to |
| 1648 | * include all inodes that need writing. Livelock avoidance is |
| 1649 | * handled by these works yielding to any other work so we are |
| 1650 | * safe. |
| 1651 | */ |
Wu Fengguang | ba9aa83 | 2010-07-21 20:32:30 -0600 | [diff] [blame] | 1652 | if (work->for_kupdate) { |
Jan Kara | 0dc83bd | 2014-02-21 11:19:04 +0100 | [diff] [blame] | 1653 | oldest_jif = jiffies - |
Wu Fengguang | ba9aa83 | 2010-07-21 20:32:30 -0600 | [diff] [blame] | 1654 | msecs_to_jiffies(dirty_expire_interval * 10); |
Jan Kara | 1bc36b6 | 2011-10-19 11:44:41 +0200 | [diff] [blame] | 1655 | } else if (work->for_background) |
Jan Kara | 0dc83bd | 2014-02-21 11:19:04 +0100 | [diff] [blame] | 1656 | oldest_jif = jiffies; |
Dave Chinner | 028c2dd | 2010-07-07 13:24:07 +1000 | [diff] [blame] | 1657 | |
Tejun Heo | 5634cc2 | 2015-08-18 14:54:56 -0700 | [diff] [blame] | 1658 | trace_writeback_start(wb, work); |
Wu Fengguang | e8dfc30 | 2011-04-21 12:06:32 -0600 | [diff] [blame] | 1659 | if (list_empty(&wb->b_io)) |
Curt Wohlgemuth | ad4e38d | 2011-10-07 21:51:56 -0600 | [diff] [blame] | 1660 | queue_io(wb, work); |
Christoph Hellwig | 83ba7b0 | 2010-07-06 08:59:53 +0200 | [diff] [blame] | 1661 | if (work->sb) |
Wu Fengguang | d46db3d | 2011-05-04 19:54:37 -0600 | [diff] [blame] | 1662 | progress = writeback_sb_inodes(work->sb, wb, work); |
Christoph Hellwig | edadfb1 | 2010-06-10 12:07:54 +0200 | [diff] [blame] | 1663 | else |
Wu Fengguang | d46db3d | 2011-05-04 19:54:37 -0600 | [diff] [blame] | 1664 | progress = __writeback_inodes_wb(wb, work); |
Tejun Heo | 5634cc2 | 2015-08-18 14:54:56 -0700 | [diff] [blame] | 1665 | trace_writeback_written(wb, work); |
Dave Chinner | 028c2dd | 2010-07-07 13:24:07 +1000 | [diff] [blame] | 1666 | |
Wu Fengguang | e98be2d | 2010-08-29 11:22:30 -0600 | [diff] [blame] | 1667 | wb_update_bandwidth(wb, wb_start); |
Jens Axboe | 03ba378 | 2009-09-09 09:08:54 +0200 | [diff] [blame] | 1668 | |
| 1669 | /* |
Jens Axboe | 71fd05a | 2009-09-23 19:32:26 +0200 | [diff] [blame] | 1670 | * Did we write something? Try for more |
Wu Fengguang | e6fb6da | 2010-07-22 10:23:44 -0600 | [diff] [blame] | 1671 | * |
| 1672 | * Dirty inodes are moved to b_io for writeback in batches. |
| 1673 | * The completion of the current batch does not necessarily |
| 1674 | * mean the overall work is done. So we keep looping as long |
| 1675 | * as made some progress on cleaning pages or inodes. |
Jens Axboe | 71fd05a | 2009-09-23 19:32:26 +0200 | [diff] [blame] | 1676 | */ |
Wu Fengguang | d46db3d | 2011-05-04 19:54:37 -0600 | [diff] [blame] | 1677 | if (progress) |
Jens Axboe | 71fd05a | 2009-09-23 19:32:26 +0200 | [diff] [blame] | 1678 | continue; |
| 1679 | /* |
Wu Fengguang | e6fb6da | 2010-07-22 10:23:44 -0600 | [diff] [blame] | 1680 | * No more inodes for IO, bail |
Jens Axboe | 71fd05a | 2009-09-23 19:32:26 +0200 | [diff] [blame] | 1681 | */ |
Wu Fengguang | b7a2441 | 2010-07-21 22:19:51 -0600 | [diff] [blame] | 1682 | if (list_empty(&wb->b_more_io)) |
Jens Axboe | 03ba378 | 2009-09-09 09:08:54 +0200 | [diff] [blame] | 1683 | break; |
| 1684 | /* |
Jens Axboe | 8010c3b | 2009-09-15 20:04:57 +0200 | [diff] [blame] | 1685 | * Nothing written. Wait for some inode to |
| 1686 | * become available for writeback. Otherwise |
| 1687 | * we'll just busyloop. |
Jens Axboe | 03ba378 | 2009-09-09 09:08:54 +0200 | [diff] [blame] | 1688 | */ |
Jens Axboe | 03ba378 | 2009-09-09 09:08:54 +0200 | [diff] [blame] | 1689 | if (!list_empty(&wb->b_more_io)) { |
Tejun Heo | 5634cc2 | 2015-08-18 14:54:56 -0700 | [diff] [blame] | 1690 | trace_writeback_wait(wb, work); |
Jens Axboe | 03ba378 | 2009-09-09 09:08:54 +0200 | [diff] [blame] | 1691 | inode = wb_inode(wb->b_more_io.prev); |
Dave Chinner | 250df6e | 2011-03-22 22:23:36 +1100 | [diff] [blame] | 1692 | spin_lock(&inode->i_lock); |
Jan Kara | f0d07b7 | 2012-05-03 14:47:59 +0200 | [diff] [blame] | 1693 | spin_unlock(&wb->list_lock); |
Jan Kara | 169ebd9 | 2012-05-03 14:48:03 +0200 | [diff] [blame] | 1694 | /* This function drops i_lock... */ |
| 1695 | inode_sleep_on_writeback(inode); |
Jan Kara | f0d07b7 | 2012-05-03 14:47:59 +0200 | [diff] [blame] | 1696 | spin_lock(&wb->list_lock); |
Jens Axboe | 03ba378 | 2009-09-09 09:08:54 +0200 | [diff] [blame] | 1697 | } |
Jens Axboe | 03ba378 | 2009-09-09 09:08:54 +0200 | [diff] [blame] | 1698 | } |
Wu Fengguang | e8dfc30 | 2011-04-21 12:06:32 -0600 | [diff] [blame] | 1699 | spin_unlock(&wb->list_lock); |
Linus Torvalds | 505a666 | 2015-09-11 13:37:19 -0700 | [diff] [blame] | 1700 | blk_finish_plug(&plug); |
Jens Axboe | 03ba378 | 2009-09-09 09:08:54 +0200 | [diff] [blame] | 1701 | |
Wu Fengguang | d46db3d | 2011-05-04 19:54:37 -0600 | [diff] [blame] | 1702 | return nr_pages - work->nr_pages; |
Jens Axboe | 03ba378 | 2009-09-09 09:08:54 +0200 | [diff] [blame] | 1703 | } |
| 1704 | |
| 1705 | /* |
Christoph Hellwig | 83ba7b0 | 2010-07-06 08:59:53 +0200 | [diff] [blame] | 1706 | * Return the next wb_writeback_work struct that hasn't been processed yet. |
Jens Axboe | 03ba378 | 2009-09-09 09:08:54 +0200 | [diff] [blame] | 1707 | */ |
Tejun Heo | f0054bb | 2015-05-22 17:13:30 -0400 | [diff] [blame] | 1708 | static struct wb_writeback_work *get_next_work_item(struct bdi_writeback *wb) |
Jens Axboe | 03ba378 | 2009-09-09 09:08:54 +0200 | [diff] [blame] | 1709 | { |
Christoph Hellwig | 83ba7b0 | 2010-07-06 08:59:53 +0200 | [diff] [blame] | 1710 | struct wb_writeback_work *work = NULL; |
Jens Axboe | 03ba378 | 2009-09-09 09:08:54 +0200 | [diff] [blame] | 1711 | |
Tejun Heo | f0054bb | 2015-05-22 17:13:30 -0400 | [diff] [blame] | 1712 | spin_lock_bh(&wb->work_lock); |
| 1713 | if (!list_empty(&wb->work_list)) { |
| 1714 | work = list_entry(wb->work_list.next, |
Christoph Hellwig | 83ba7b0 | 2010-07-06 08:59:53 +0200 | [diff] [blame] | 1715 | struct wb_writeback_work, list); |
| 1716 | list_del_init(&work->list); |
Jens Axboe | 03ba378 | 2009-09-09 09:08:54 +0200 | [diff] [blame] | 1717 | } |
Tejun Heo | f0054bb | 2015-05-22 17:13:30 -0400 | [diff] [blame] | 1718 | spin_unlock_bh(&wb->work_lock); |
Christoph Hellwig | 83ba7b0 | 2010-07-06 08:59:53 +0200 | [diff] [blame] | 1719 | return work; |
Jens Axboe | 03ba378 | 2009-09-09 09:08:54 +0200 | [diff] [blame] | 1720 | } |
| 1721 | |
Linus Torvalds | cdf01dd | 2010-10-30 08:55:52 -0700 | [diff] [blame] | 1722 | /* |
| 1723 | * Add in the number of potentially dirty inodes, because each inode |
| 1724 | * write can dirty pagecache in the underlying blockdev. |
| 1725 | */ |
| 1726 | static unsigned long get_nr_dirty_pages(void) |
| 1727 | { |
| 1728 | return global_page_state(NR_FILE_DIRTY) + |
| 1729 | global_page_state(NR_UNSTABLE_NFS) + |
| 1730 | get_nr_dirty_inodes(); |
| 1731 | } |
| 1732 | |
Jan Kara | 6585027 | 2011-01-13 15:45:44 -0800 | [diff] [blame] | 1733 | static long wb_check_background_flush(struct bdi_writeback *wb) |
| 1734 | { |
Tejun Heo | aa661bb | 2015-05-22 18:23:31 -0400 | [diff] [blame] | 1735 | if (wb_over_bg_thresh(wb)) { |
Jan Kara | 6585027 | 2011-01-13 15:45:44 -0800 | [diff] [blame] | 1736 | |
| 1737 | struct wb_writeback_work work = { |
| 1738 | .nr_pages = LONG_MAX, |
| 1739 | .sync_mode = WB_SYNC_NONE, |
| 1740 | .for_background = 1, |
| 1741 | .range_cyclic = 1, |
Curt Wohlgemuth | 0e175a1 | 2011-10-07 21:54:10 -0600 | [diff] [blame] | 1742 | .reason = WB_REASON_BACKGROUND, |
Jan Kara | 6585027 | 2011-01-13 15:45:44 -0800 | [diff] [blame] | 1743 | }; |
| 1744 | |
| 1745 | return wb_writeback(wb, &work); |
| 1746 | } |
| 1747 | |
| 1748 | return 0; |
| 1749 | } |
| 1750 | |
Jens Axboe | 03ba378 | 2009-09-09 09:08:54 +0200 | [diff] [blame] | 1751 | static long wb_check_old_data_flush(struct bdi_writeback *wb) |
| 1752 | { |
| 1753 | unsigned long expired; |
| 1754 | long nr_pages; |
| 1755 | |
Jens Axboe | 69b62d0 | 2010-05-17 12:51:03 +0200 | [diff] [blame] | 1756 | /* |
| 1757 | * When set to zero, disable periodic writeback |
| 1758 | */ |
| 1759 | if (!dirty_writeback_interval) |
| 1760 | return 0; |
| 1761 | |
Jens Axboe | 03ba378 | 2009-09-09 09:08:54 +0200 | [diff] [blame] | 1762 | expired = wb->last_old_flush + |
| 1763 | msecs_to_jiffies(dirty_writeback_interval * 10); |
| 1764 | if (time_before(jiffies, expired)) |
| 1765 | return 0; |
| 1766 | |
| 1767 | wb->last_old_flush = jiffies; |
Linus Torvalds | cdf01dd | 2010-10-30 08:55:52 -0700 | [diff] [blame] | 1768 | nr_pages = get_nr_dirty_pages(); |
Jens Axboe | 03ba378 | 2009-09-09 09:08:54 +0200 | [diff] [blame] | 1769 | |
Jens Axboe | c4a77a6 | 2009-09-16 15:18:25 +0200 | [diff] [blame] | 1770 | if (nr_pages) { |
Christoph Hellwig | 83ba7b0 | 2010-07-06 08:59:53 +0200 | [diff] [blame] | 1771 | struct wb_writeback_work work = { |
Jens Axboe | c4a77a6 | 2009-09-16 15:18:25 +0200 | [diff] [blame] | 1772 | .nr_pages = nr_pages, |
| 1773 | .sync_mode = WB_SYNC_NONE, |
| 1774 | .for_kupdate = 1, |
| 1775 | .range_cyclic = 1, |
Curt Wohlgemuth | 0e175a1 | 2011-10-07 21:54:10 -0600 | [diff] [blame] | 1776 | .reason = WB_REASON_PERIODIC, |
Jens Axboe | c4a77a6 | 2009-09-16 15:18:25 +0200 | [diff] [blame] | 1777 | }; |
| 1778 | |
Christoph Hellwig | 83ba7b0 | 2010-07-06 08:59:53 +0200 | [diff] [blame] | 1779 | return wb_writeback(wb, &work); |
Jens Axboe | c4a77a6 | 2009-09-16 15:18:25 +0200 | [diff] [blame] | 1780 | } |
Jens Axboe | 03ba378 | 2009-09-09 09:08:54 +0200 | [diff] [blame] | 1781 | |
| 1782 | return 0; |
| 1783 | } |
| 1784 | |
| 1785 | /* |
| 1786 | * Retrieve work items and do the writeback they describe |
| 1787 | */ |
Wanpeng Li | 25d130b | 2013-07-08 16:00:14 -0700 | [diff] [blame] | 1788 | static long wb_do_writeback(struct bdi_writeback *wb) |
Jens Axboe | 03ba378 | 2009-09-09 09:08:54 +0200 | [diff] [blame] | 1789 | { |
Christoph Hellwig | 83ba7b0 | 2010-07-06 08:59:53 +0200 | [diff] [blame] | 1790 | struct wb_writeback_work *work; |
Jens Axboe | c4a77a6 | 2009-09-16 15:18:25 +0200 | [diff] [blame] | 1791 | long wrote = 0; |
Jens Axboe | 03ba378 | 2009-09-09 09:08:54 +0200 | [diff] [blame] | 1792 | |
Tejun Heo | 4452226 | 2015-05-22 17:13:26 -0400 | [diff] [blame] | 1793 | set_bit(WB_writeback_running, &wb->state); |
Tejun Heo | f0054bb | 2015-05-22 17:13:30 -0400 | [diff] [blame] | 1794 | while ((work = get_next_work_item(wb)) != NULL) { |
Tejun Heo | cc395d7 | 2015-05-22 17:13:58 -0400 | [diff] [blame] | 1795 | struct wb_completion *done = work->done; |
Christoph Hellwig | 83ba7b0 | 2010-07-06 08:59:53 +0200 | [diff] [blame] | 1796 | |
Tejun Heo | 5634cc2 | 2015-08-18 14:54:56 -0700 | [diff] [blame] | 1797 | trace_writeback_exec(wb, work); |
Dave Chinner | 455b286 | 2010-07-07 13:24:06 +1000 | [diff] [blame] | 1798 | |
Christoph Hellwig | 83ba7b0 | 2010-07-06 08:59:53 +0200 | [diff] [blame] | 1799 | wrote += wb_writeback(wb, work); |
Jens Axboe | 03ba378 | 2009-09-09 09:08:54 +0200 | [diff] [blame] | 1800 | |
Tejun Heo | 8a1270c | 2015-08-18 14:54:53 -0700 | [diff] [blame] | 1801 | if (work->auto_free) |
Christoph Hellwig | 83ba7b0 | 2010-07-06 08:59:53 +0200 | [diff] [blame] | 1802 | kfree(work); |
Tejun Heo | cc395d7 | 2015-05-22 17:13:58 -0400 | [diff] [blame] | 1803 | if (done && atomic_dec_and_test(&done->cnt)) |
| 1804 | wake_up_all(&wb->bdi->wb_waitq); |
Jens Axboe | 03ba378 | 2009-09-09 09:08:54 +0200 | [diff] [blame] | 1805 | } |
| 1806 | |
| 1807 | /* |
| 1808 | * Check for periodic writeback, kupdated() style |
| 1809 | */ |
| 1810 | wrote += wb_check_old_data_flush(wb); |
Jan Kara | 6585027 | 2011-01-13 15:45:44 -0800 | [diff] [blame] | 1811 | wrote += wb_check_background_flush(wb); |
Tejun Heo | 4452226 | 2015-05-22 17:13:26 -0400 | [diff] [blame] | 1812 | clear_bit(WB_writeback_running, &wb->state); |
Jens Axboe | 03ba378 | 2009-09-09 09:08:54 +0200 | [diff] [blame] | 1813 | |
| 1814 | return wrote; |
| 1815 | } |
| 1816 | |
| 1817 | /* |
| 1818 | * Handle writeback of dirty data for the device backed by this bdi. Also |
Tejun Heo | 839a8e8 | 2013-04-01 19:08:06 -0700 | [diff] [blame] | 1819 | * reschedules periodically and does kupdated style flushing. |
Jens Axboe | 03ba378 | 2009-09-09 09:08:54 +0200 | [diff] [blame] | 1820 | */ |
Tejun Heo | f0054bb | 2015-05-22 17:13:30 -0400 | [diff] [blame] | 1821 | void wb_workfn(struct work_struct *work) |
Jens Axboe | 03ba378 | 2009-09-09 09:08:54 +0200 | [diff] [blame] | 1822 | { |
Tejun Heo | 839a8e8 | 2013-04-01 19:08:06 -0700 | [diff] [blame] | 1823 | struct bdi_writeback *wb = container_of(to_delayed_work(work), |
| 1824 | struct bdi_writeback, dwork); |
Jens Axboe | 03ba378 | 2009-09-09 09:08:54 +0200 | [diff] [blame] | 1825 | long pages_written; |
| 1826 | |
Tejun Heo | f0054bb | 2015-05-22 17:13:30 -0400 | [diff] [blame] | 1827 | set_worker_desc("flush-%s", dev_name(wb->bdi->dev)); |
Peter Zijlstra | 766f916 | 2010-10-26 14:22:45 -0700 | [diff] [blame] | 1828 | current->flags |= PF_SWAPWRITE; |
Christoph Hellwig | 0824390 | 2010-06-19 23:08:22 +0200 | [diff] [blame] | 1829 | |
Tejun Heo | 839a8e8 | 2013-04-01 19:08:06 -0700 | [diff] [blame] | 1830 | if (likely(!current_is_workqueue_rescuer() || |
Tejun Heo | 4452226 | 2015-05-22 17:13:26 -0400 | [diff] [blame] | 1831 | !test_bit(WB_registered, &wb->state))) { |
Artem Bityutskiy | 6467716 | 2010-07-25 14:29:22 +0300 | [diff] [blame] | 1832 | /* |
Tejun Heo | f0054bb | 2015-05-22 17:13:30 -0400 | [diff] [blame] | 1833 | * The normal path. Keep writing back @wb until its |
Tejun Heo | 839a8e8 | 2013-04-01 19:08:06 -0700 | [diff] [blame] | 1834 | * work_list is empty. Note that this path is also taken |
Tejun Heo | f0054bb | 2015-05-22 17:13:30 -0400 | [diff] [blame] | 1835 | * if @wb is shutting down even when we're running off the |
Tejun Heo | 839a8e8 | 2013-04-01 19:08:06 -0700 | [diff] [blame] | 1836 | * rescuer as work_list needs to be drained. |
Artem Bityutskiy | 6467716 | 2010-07-25 14:29:22 +0300 | [diff] [blame] | 1837 | */ |
Tejun Heo | 839a8e8 | 2013-04-01 19:08:06 -0700 | [diff] [blame] | 1838 | do { |
Wanpeng Li | 25d130b | 2013-07-08 16:00:14 -0700 | [diff] [blame] | 1839 | pages_written = wb_do_writeback(wb); |
Tejun Heo | 839a8e8 | 2013-04-01 19:08:06 -0700 | [diff] [blame] | 1840 | trace_writeback_pages_written(pages_written); |
Tejun Heo | f0054bb | 2015-05-22 17:13:30 -0400 | [diff] [blame] | 1841 | } while (!list_empty(&wb->work_list)); |
Tejun Heo | 839a8e8 | 2013-04-01 19:08:06 -0700 | [diff] [blame] | 1842 | } else { |
| 1843 | /* |
| 1844 | * bdi_wq can't get enough workers and we're running off |
| 1845 | * the emergency worker. Don't hog it. Hopefully, 1024 is |
| 1846 | * enough for efficient IO. |
| 1847 | */ |
Tejun Heo | f0054bb | 2015-05-22 17:13:30 -0400 | [diff] [blame] | 1848 | pages_written = writeback_inodes_wb(wb, 1024, |
Tejun Heo | 839a8e8 | 2013-04-01 19:08:06 -0700 | [diff] [blame] | 1849 | WB_REASON_FORKER_THREAD); |
Dave Chinner | 455b286 | 2010-07-07 13:24:06 +1000 | [diff] [blame] | 1850 | trace_writeback_pages_written(pages_written); |
Jens Axboe | 03ba378 | 2009-09-09 09:08:54 +0200 | [diff] [blame] | 1851 | } |
| 1852 | |
Tejun Heo | f0054bb | 2015-05-22 17:13:30 -0400 | [diff] [blame] | 1853 | if (!list_empty(&wb->work_list)) |
Derek Basehore | 6ca738d | 2014-04-03 14:46:22 -0700 | [diff] [blame] | 1854 | mod_delayed_work(bdi_wq, &wb->dwork, 0); |
| 1855 | else if (wb_has_dirty_io(wb) && dirty_writeback_interval) |
Tejun Heo | f0054bb | 2015-05-22 17:13:30 -0400 | [diff] [blame] | 1856 | wb_wakeup_delayed(wb); |
Dave Chinner | 455b286 | 2010-07-07 13:24:06 +1000 | [diff] [blame] | 1857 | |
Tejun Heo | 839a8e8 | 2013-04-01 19:08:06 -0700 | [diff] [blame] | 1858 | current->flags &= ~PF_SWAPWRITE; |
Jens Axboe | 03ba378 | 2009-09-09 09:08:54 +0200 | [diff] [blame] | 1859 | } |
| 1860 | |
| 1861 | /* |
Jens Axboe | 03ba378 | 2009-09-09 09:08:54 +0200 | [diff] [blame] | 1862 | * Start writeback of `nr_pages' pages. If `nr_pages' is zero, write back |
| 1863 | * the whole world. |
| 1864 | */ |
Curt Wohlgemuth | 0e175a1 | 2011-10-07 21:54:10 -0600 | [diff] [blame] | 1865 | void wakeup_flusher_threads(long nr_pages, enum wb_reason reason) |
Jens Axboe | 03ba378 | 2009-09-09 09:08:54 +0200 | [diff] [blame] | 1866 | { |
Christoph Hellwig | b8c2f34 | 2010-06-08 18:15:07 +0200 | [diff] [blame] | 1867 | struct backing_dev_info *bdi; |
Christoph Hellwig | b8c2f34 | 2010-06-08 18:15:07 +0200 | [diff] [blame] | 1868 | |
Jan Kara | 47df3dd | 2013-09-11 14:22:22 -0700 | [diff] [blame] | 1869 | if (!nr_pages) |
| 1870 | nr_pages = get_nr_dirty_pages(); |
Christoph Hellwig | b8c2f34 | 2010-06-08 18:15:07 +0200 | [diff] [blame] | 1871 | |
| 1872 | rcu_read_lock(); |
Tejun Heo | f2b6512 | 2015-05-22 17:13:55 -0400 | [diff] [blame] | 1873 | list_for_each_entry_rcu(bdi, &bdi_list, bdi_list) { |
| 1874 | struct bdi_writeback *wb; |
Tejun Heo | f2b6512 | 2015-05-22 17:13:55 -0400 | [diff] [blame] | 1875 | |
| 1876 | if (!bdi_has_dirty_io(bdi)) |
| 1877 | continue; |
| 1878 | |
Tejun Heo | b817525 | 2015-10-02 14:47:05 -0400 | [diff] [blame] | 1879 | list_for_each_entry_rcu(wb, &bdi->wb_list, bdi_node) |
Tejun Heo | f2b6512 | 2015-05-22 17:13:55 -0400 | [diff] [blame] | 1880 | wb_start_writeback(wb, wb_split_bdi_pages(wb, nr_pages), |
| 1881 | false, reason); |
| 1882 | } |
Christoph Hellwig | b8c2f34 | 2010-06-08 18:15:07 +0200 | [diff] [blame] | 1883 | rcu_read_unlock(); |
Jens Axboe | 03ba378 | 2009-09-09 09:08:54 +0200 | [diff] [blame] | 1884 | } |
| 1885 | |
Theodore Ts'o | a2f4870 | 2015-03-17 12:23:19 -0400 | [diff] [blame] | 1886 | /* |
| 1887 | * Wake up bdi's periodically to make sure dirtytime inodes gets |
| 1888 | * written back periodically. We deliberately do *not* check the |
| 1889 | * b_dirtytime list in wb_has_dirty_io(), since this would cause the |
| 1890 | * kernel to be constantly waking up once there are any dirtytime |
| 1891 | * inodes on the system. So instead we define a separate delayed work |
| 1892 | * function which gets called much more rarely. (By default, only |
| 1893 | * once every 12 hours.) |
| 1894 | * |
| 1895 | * If there is any other write activity going on in the file system, |
| 1896 | * this function won't be necessary. But if the only thing that has |
| 1897 | * happened on the file system is a dirtytime inode caused by an atime |
| 1898 | * update, we need this infrastructure below to make sure that inode |
| 1899 | * eventually gets pushed out to disk. |
| 1900 | */ |
| 1901 | static void wakeup_dirtytime_writeback(struct work_struct *w); |
| 1902 | static DECLARE_DELAYED_WORK(dirtytime_work, wakeup_dirtytime_writeback); |
| 1903 | |
| 1904 | static void wakeup_dirtytime_writeback(struct work_struct *w) |
| 1905 | { |
| 1906 | struct backing_dev_info *bdi; |
| 1907 | |
| 1908 | rcu_read_lock(); |
| 1909 | list_for_each_entry_rcu(bdi, &bdi_list, bdi_list) { |
Tejun Heo | 001fe6f | 2015-05-22 17:13:56 -0400 | [diff] [blame] | 1910 | struct bdi_writeback *wb; |
Tejun Heo | 001fe6f | 2015-05-22 17:13:56 -0400 | [diff] [blame] | 1911 | |
Tejun Heo | b817525 | 2015-10-02 14:47:05 -0400 | [diff] [blame] | 1912 | list_for_each_entry_rcu(wb, &bdi->wb_list, bdi_node) |
Tejun Heo | 6fdf860 | 2015-09-29 12:47:51 -0400 | [diff] [blame] | 1913 | if (!list_empty(&wb->b_dirty_time)) |
| 1914 | wb_wakeup(wb); |
Theodore Ts'o | a2f4870 | 2015-03-17 12:23:19 -0400 | [diff] [blame] | 1915 | } |
| 1916 | rcu_read_unlock(); |
| 1917 | schedule_delayed_work(&dirtytime_work, dirtytime_expire_interval * HZ); |
| 1918 | } |
| 1919 | |
| 1920 | static int __init start_dirtytime_writeback(void) |
| 1921 | { |
| 1922 | schedule_delayed_work(&dirtytime_work, dirtytime_expire_interval * HZ); |
| 1923 | return 0; |
| 1924 | } |
| 1925 | __initcall(start_dirtytime_writeback); |
| 1926 | |
Theodore Ts'o | 1efff91 | 2015-03-17 12:23:32 -0400 | [diff] [blame] | 1927 | int dirtytime_interval_handler(struct ctl_table *table, int write, |
| 1928 | void __user *buffer, size_t *lenp, loff_t *ppos) |
| 1929 | { |
| 1930 | int ret; |
| 1931 | |
| 1932 | ret = proc_dointvec_minmax(table, write, buffer, lenp, ppos); |
| 1933 | if (ret == 0 && write) |
| 1934 | mod_delayed_work(system_wq, &dirtytime_work, 0); |
| 1935 | return ret; |
| 1936 | } |
| 1937 | |
Jens Axboe | 03ba378 | 2009-09-09 09:08:54 +0200 | [diff] [blame] | 1938 | static noinline void block_dump___mark_inode_dirty(struct inode *inode) |
| 1939 | { |
| 1940 | if (inode->i_ino || strcmp(inode->i_sb->s_id, "bdev")) { |
| 1941 | struct dentry *dentry; |
| 1942 | const char *name = "?"; |
| 1943 | |
| 1944 | dentry = d_find_alias(inode); |
| 1945 | if (dentry) { |
| 1946 | spin_lock(&dentry->d_lock); |
| 1947 | name = (const char *) dentry->d_name.name; |
| 1948 | } |
| 1949 | printk(KERN_DEBUG |
| 1950 | "%s(%d): dirtied inode %lu (%s) on %s\n", |
| 1951 | current->comm, task_pid_nr(current), inode->i_ino, |
| 1952 | name, inode->i_sb->s_id); |
| 1953 | if (dentry) { |
| 1954 | spin_unlock(&dentry->d_lock); |
| 1955 | dput(dentry); |
| 1956 | } |
| 1957 | } |
| 1958 | } |
| 1959 | |
| 1960 | /** |
| 1961 | * __mark_inode_dirty - internal function |
| 1962 | * @inode: inode to mark |
| 1963 | * @flags: what kind of dirty (i.e. I_DIRTY_SYNC) |
| 1964 | * Mark an inode as dirty. Callers should use mark_inode_dirty or |
| 1965 | * mark_inode_dirty_sync. |
| 1966 | * |
| 1967 | * Put the inode on the super block's dirty list. |
| 1968 | * |
| 1969 | * CAREFUL! We mark it dirty unconditionally, but move it onto the |
| 1970 | * dirty list only if it is hashed or if it refers to a blockdev. |
| 1971 | * If it was not hashed, it will never be added to the dirty list |
| 1972 | * even if it is later hashed, as it will have been marked dirty already. |
| 1973 | * |
| 1974 | * In short, make sure you hash any inodes _before_ you start marking |
| 1975 | * them dirty. |
| 1976 | * |
Jens Axboe | 03ba378 | 2009-09-09 09:08:54 +0200 | [diff] [blame] | 1977 | * Note that for blockdevs, inode->dirtied_when represents the dirtying time of |
| 1978 | * the block-special inode (/dev/hda1) itself. And the ->dirtied_when field of |
| 1979 | * the kernel-internal blockdev inode represents the dirtying time of the |
| 1980 | * blockdev's pages. This is why for I_DIRTY_PAGES we always use |
| 1981 | * page->mapping->host, so the page-dirtying time is recorded in the internal |
| 1982 | * blockdev inode. |
| 1983 | */ |
Theodore Ts'o | 0ae45f6 | 2015-02-02 00:37:00 -0500 | [diff] [blame] | 1984 | #define I_DIRTY_INODE (I_DIRTY_SYNC | I_DIRTY_DATASYNC) |
Jens Axboe | 03ba378 | 2009-09-09 09:08:54 +0200 | [diff] [blame] | 1985 | void __mark_inode_dirty(struct inode *inode, int flags) |
| 1986 | { |
| 1987 | struct super_block *sb = inode->i_sb; |
Theodore Ts'o | 0ae45f6 | 2015-02-02 00:37:00 -0500 | [diff] [blame] | 1988 | int dirtytime; |
| 1989 | |
| 1990 | trace_writeback_mark_inode_dirty(inode, flags); |
Jens Axboe | 03ba378 | 2009-09-09 09:08:54 +0200 | [diff] [blame] | 1991 | |
| 1992 | /* |
| 1993 | * Don't do this for I_DIRTY_PAGES - that doesn't actually |
| 1994 | * dirty the inode itself |
| 1995 | */ |
Theodore Ts'o | 0ae45f6 | 2015-02-02 00:37:00 -0500 | [diff] [blame] | 1996 | if (flags & (I_DIRTY_SYNC | I_DIRTY_DATASYNC | I_DIRTY_TIME)) { |
Tejun Heo | 9fb0a7d | 2013-01-11 13:06:37 -0800 | [diff] [blame] | 1997 | trace_writeback_dirty_inode_start(inode, flags); |
| 1998 | |
Jens Axboe | 03ba378 | 2009-09-09 09:08:54 +0200 | [diff] [blame] | 1999 | if (sb->s_op->dirty_inode) |
Christoph Hellwig | aa38572 | 2011-05-27 06:53:02 -0400 | [diff] [blame] | 2000 | sb->s_op->dirty_inode(inode, flags); |
Tejun Heo | 9fb0a7d | 2013-01-11 13:06:37 -0800 | [diff] [blame] | 2001 | |
| 2002 | trace_writeback_dirty_inode(inode, flags); |
Jens Axboe | 03ba378 | 2009-09-09 09:08:54 +0200 | [diff] [blame] | 2003 | } |
Theodore Ts'o | 0ae45f6 | 2015-02-02 00:37:00 -0500 | [diff] [blame] | 2004 | if (flags & I_DIRTY_INODE) |
| 2005 | flags &= ~I_DIRTY_TIME; |
| 2006 | dirtytime = flags & I_DIRTY_TIME; |
Jens Axboe | 03ba378 | 2009-09-09 09:08:54 +0200 | [diff] [blame] | 2007 | |
| 2008 | /* |
Tejun Heo | 9c6ac78 | 2014-10-24 15:38:21 -0400 | [diff] [blame] | 2009 | * Paired with smp_mb() in __writeback_single_inode() for the |
| 2010 | * following lockless i_state test. See there for details. |
Jens Axboe | 03ba378 | 2009-09-09 09:08:54 +0200 | [diff] [blame] | 2011 | */ |
| 2012 | smp_mb(); |
| 2013 | |
Theodore Ts'o | 0ae45f6 | 2015-02-02 00:37:00 -0500 | [diff] [blame] | 2014 | if (((inode->i_state & flags) == flags) || |
| 2015 | (dirtytime && (inode->i_state & I_DIRTY_INODE))) |
Jens Axboe | 03ba378 | 2009-09-09 09:08:54 +0200 | [diff] [blame] | 2016 | return; |
| 2017 | |
| 2018 | if (unlikely(block_dump)) |
| 2019 | block_dump___mark_inode_dirty(inode); |
| 2020 | |
Dave Chinner | 250df6e | 2011-03-22 22:23:36 +1100 | [diff] [blame] | 2021 | spin_lock(&inode->i_lock); |
Theodore Ts'o | 0ae45f6 | 2015-02-02 00:37:00 -0500 | [diff] [blame] | 2022 | if (dirtytime && (inode->i_state & I_DIRTY_INODE)) |
| 2023 | goto out_unlock_inode; |
Jens Axboe | 03ba378 | 2009-09-09 09:08:54 +0200 | [diff] [blame] | 2024 | if ((inode->i_state & flags) != flags) { |
| 2025 | const int was_dirty = inode->i_state & I_DIRTY; |
| 2026 | |
Tejun Heo | 52ebea7 | 2015-05-22 17:13:37 -0400 | [diff] [blame] | 2027 | inode_attach_wb(inode, NULL); |
| 2028 | |
Theodore Ts'o | 0ae45f6 | 2015-02-02 00:37:00 -0500 | [diff] [blame] | 2029 | if (flags & I_DIRTY_INODE) |
| 2030 | inode->i_state &= ~I_DIRTY_TIME; |
Jens Axboe | 03ba378 | 2009-09-09 09:08:54 +0200 | [diff] [blame] | 2031 | inode->i_state |= flags; |
| 2032 | |
| 2033 | /* |
| 2034 | * If the inode is being synced, just update its dirty state. |
| 2035 | * The unlocker will place the inode on the appropriate |
| 2036 | * superblock list, based upon its state. |
| 2037 | */ |
| 2038 | if (inode->i_state & I_SYNC) |
Dave Chinner | 250df6e | 2011-03-22 22:23:36 +1100 | [diff] [blame] | 2039 | goto out_unlock_inode; |
Jens Axboe | 03ba378 | 2009-09-09 09:08:54 +0200 | [diff] [blame] | 2040 | |
| 2041 | /* |
| 2042 | * Only add valid (hashed) inodes to the superblock's |
| 2043 | * dirty list. Add blockdev inodes as well. |
| 2044 | */ |
| 2045 | if (!S_ISBLK(inode->i_mode)) { |
Al Viro | 1d3382cb | 2010-10-23 15:19:20 -0400 | [diff] [blame] | 2046 | if (inode_unhashed(inode)) |
Dave Chinner | 250df6e | 2011-03-22 22:23:36 +1100 | [diff] [blame] | 2047 | goto out_unlock_inode; |
Jens Axboe | 03ba378 | 2009-09-09 09:08:54 +0200 | [diff] [blame] | 2048 | } |
Al Viro | a4ffdde | 2010-06-02 17:38:30 -0400 | [diff] [blame] | 2049 | if (inode->i_state & I_FREEING) |
Dave Chinner | 250df6e | 2011-03-22 22:23:36 +1100 | [diff] [blame] | 2050 | goto out_unlock_inode; |
Jens Axboe | 03ba378 | 2009-09-09 09:08:54 +0200 | [diff] [blame] | 2051 | |
| 2052 | /* |
| 2053 | * If the inode was already on b_dirty/b_io/b_more_io, don't |
| 2054 | * reposition it (that would break b_dirty time-ordering). |
| 2055 | */ |
| 2056 | if (!was_dirty) { |
Tejun Heo | 87e1d78 | 2015-05-28 14:50:52 -0400 | [diff] [blame] | 2057 | struct bdi_writeback *wb; |
Tejun Heo | d6c10f1 | 2015-05-22 17:13:45 -0400 | [diff] [blame] | 2058 | struct list_head *dirty_list; |
Dave Chinner | a66979a | 2011-03-22 22:23:41 +1100 | [diff] [blame] | 2059 | bool wakeup_bdi = false; |
Jens Axboe | 500b067 | 2009-09-09 09:10:25 +0200 | [diff] [blame] | 2060 | |
Tejun Heo | 87e1d78 | 2015-05-28 14:50:52 -0400 | [diff] [blame] | 2061 | wb = locked_inode_to_wb_and_lock_list(inode); |
Artem Bityutskiy | 253c34e | 2010-07-25 14:29:21 +0300 | [diff] [blame] | 2062 | |
Tejun Heo | 0747259 | 2015-05-22 17:14:02 -0400 | [diff] [blame] | 2063 | WARN(bdi_cap_writeback_dirty(wb->bdi) && |
| 2064 | !test_bit(WB_registered, &wb->state), |
| 2065 | "bdi-%s not registered\n", wb->bdi->name); |
Jens Axboe | 03ba378 | 2009-09-09 09:08:54 +0200 | [diff] [blame] | 2066 | |
| 2067 | inode->dirtied_when = jiffies; |
Theodore Ts'o | a2f4870 | 2015-03-17 12:23:19 -0400 | [diff] [blame] | 2068 | if (dirtytime) |
| 2069 | inode->dirtied_time_when = jiffies; |
Tejun Heo | d6c10f1 | 2015-05-22 17:13:45 -0400 | [diff] [blame] | 2070 | |
Theodore Ts'o | a2f4870 | 2015-03-17 12:23:19 -0400 | [diff] [blame] | 2071 | if (inode->i_state & (I_DIRTY_INODE | I_DIRTY_PAGES)) |
Tejun Heo | 0747259 | 2015-05-22 17:14:02 -0400 | [diff] [blame] | 2072 | dirty_list = &wb->b_dirty; |
Theodore Ts'o | a2f4870 | 2015-03-17 12:23:19 -0400 | [diff] [blame] | 2073 | else |
Tejun Heo | 0747259 | 2015-05-22 17:14:02 -0400 | [diff] [blame] | 2074 | dirty_list = &wb->b_dirty_time; |
Tejun Heo | d6c10f1 | 2015-05-22 17:13:45 -0400 | [diff] [blame] | 2075 | |
Dave Chinner | c7f5408 | 2015-03-04 14:07:22 -0500 | [diff] [blame] | 2076 | wakeup_bdi = inode_io_list_move_locked(inode, wb, |
Tejun Heo | d6c10f1 | 2015-05-22 17:13:45 -0400 | [diff] [blame] | 2077 | dirty_list); |
| 2078 | |
Tejun Heo | 0747259 | 2015-05-22 17:14:02 -0400 | [diff] [blame] | 2079 | spin_unlock(&wb->list_lock); |
Theodore Ts'o | 0ae45f6 | 2015-02-02 00:37:00 -0500 | [diff] [blame] | 2080 | trace_writeback_dirty_inode_enqueue(inode); |
Dave Chinner | a66979a | 2011-03-22 22:23:41 +1100 | [diff] [blame] | 2081 | |
Tejun Heo | d6c10f1 | 2015-05-22 17:13:45 -0400 | [diff] [blame] | 2082 | /* |
| 2083 | * If this is the first dirty inode for this bdi, |
| 2084 | * we have to wake-up the corresponding bdi thread |
| 2085 | * to make sure background write-back happens |
| 2086 | * later. |
| 2087 | */ |
Tejun Heo | 0747259 | 2015-05-22 17:14:02 -0400 | [diff] [blame] | 2088 | if (bdi_cap_writeback_dirty(wb->bdi) && wakeup_bdi) |
| 2089 | wb_wakeup_delayed(wb); |
Dave Chinner | a66979a | 2011-03-22 22:23:41 +1100 | [diff] [blame] | 2090 | return; |
Jens Axboe | 03ba378 | 2009-09-09 09:08:54 +0200 | [diff] [blame] | 2091 | } |
| 2092 | } |
Dave Chinner | 250df6e | 2011-03-22 22:23:36 +1100 | [diff] [blame] | 2093 | out_unlock_inode: |
| 2094 | spin_unlock(&inode->i_lock); |
Artem Bityutskiy | 253c34e | 2010-07-25 14:29:21 +0300 | [diff] [blame] | 2095 | |
Jens Axboe | 03ba378 | 2009-09-09 09:08:54 +0200 | [diff] [blame] | 2096 | } |
| 2097 | EXPORT_SYMBOL(__mark_inode_dirty); |
| 2098 | |
Dave Chinner | e97fedb | 2015-03-04 13:40:00 -0500 | [diff] [blame] | 2099 | /* |
| 2100 | * The @s_sync_lock is used to serialise concurrent sync operations |
| 2101 | * to avoid lock contention problems with concurrent wait_sb_inodes() calls. |
| 2102 | * Concurrent callers will block on the s_sync_lock rather than doing contending |
| 2103 | * walks. The queueing maintains sync(2) required behaviour as all the IO that |
| 2104 | * has been issued up to the time this function is enter is guaranteed to be |
| 2105 | * completed by the time we have gained the lock and waited for all IO that is |
| 2106 | * in progress regardless of the order callers are granted the lock. |
| 2107 | */ |
Jens Axboe | b6e5131 | 2009-09-16 15:13:54 +0200 | [diff] [blame] | 2108 | static void wait_sb_inodes(struct super_block *sb) |
Jens Axboe | 66f3b8e | 2009-09-02 09:19:46 +0200 | [diff] [blame] | 2109 | { |
Jens Axboe | 03ba378 | 2009-09-09 09:08:54 +0200 | [diff] [blame] | 2110 | struct inode *inode, *old_inode = NULL; |
Jens Axboe | 66f3b8e | 2009-09-02 09:19:46 +0200 | [diff] [blame] | 2111 | |
Jens Axboe | 03ba378 | 2009-09-09 09:08:54 +0200 | [diff] [blame] | 2112 | /* |
| 2113 | * We need to be protected against the filesystem going from |
| 2114 | * r/o to r/w or vice versa. |
| 2115 | */ |
Jens Axboe | b6e5131 | 2009-09-16 15:13:54 +0200 | [diff] [blame] | 2116 | WARN_ON(!rwsem_is_locked(&sb->s_umount)); |
Jens Axboe | 66f3b8e | 2009-09-02 09:19:46 +0200 | [diff] [blame] | 2117 | |
Dave Chinner | e97fedb | 2015-03-04 13:40:00 -0500 | [diff] [blame] | 2118 | mutex_lock(&sb->s_sync_lock); |
Dave Chinner | 74278da | 2015-03-04 12:37:22 -0500 | [diff] [blame] | 2119 | spin_lock(&sb->s_inode_list_lock); |
Jens Axboe | 03ba378 | 2009-09-09 09:08:54 +0200 | [diff] [blame] | 2120 | |
| 2121 | /* |
| 2122 | * Data integrity sync. Must wait for all pages under writeback, |
| 2123 | * because there may have been pages dirtied before our sync |
| 2124 | * call, but which had writeout started before we write it out. |
| 2125 | * In which case, the inode may not be on the dirty list, but |
| 2126 | * we still have to wait for that writeout. |
| 2127 | */ |
Jens Axboe | b6e5131 | 2009-09-16 15:13:54 +0200 | [diff] [blame] | 2128 | list_for_each_entry(inode, &sb->s_inodes, i_sb_list) { |
Dave Chinner | 250df6e | 2011-03-22 22:23:36 +1100 | [diff] [blame] | 2129 | struct address_space *mapping = inode->i_mapping; |
Jens Axboe | 03ba378 | 2009-09-09 09:08:54 +0200 | [diff] [blame] | 2130 | |
Dave Chinner | 250df6e | 2011-03-22 22:23:36 +1100 | [diff] [blame] | 2131 | spin_lock(&inode->i_lock); |
| 2132 | if ((inode->i_state & (I_FREEING|I_WILL_FREE|I_NEW)) || |
| 2133 | (mapping->nrpages == 0)) { |
| 2134 | spin_unlock(&inode->i_lock); |
Jens Axboe | 03ba378 | 2009-09-09 09:08:54 +0200 | [diff] [blame] | 2135 | continue; |
Dave Chinner | 250df6e | 2011-03-22 22:23:36 +1100 | [diff] [blame] | 2136 | } |
Jens Axboe | 03ba378 | 2009-09-09 09:08:54 +0200 | [diff] [blame] | 2137 | __iget(inode); |
Dave Chinner | 250df6e | 2011-03-22 22:23:36 +1100 | [diff] [blame] | 2138 | spin_unlock(&inode->i_lock); |
Dave Chinner | 74278da | 2015-03-04 12:37:22 -0500 | [diff] [blame] | 2139 | spin_unlock(&sb->s_inode_list_lock); |
Dave Chinner | 55fa609 | 2011-03-22 22:23:40 +1100 | [diff] [blame] | 2140 | |
Jens Axboe | 03ba378 | 2009-09-09 09:08:54 +0200 | [diff] [blame] | 2141 | /* |
Dave Chinner | 55fa609 | 2011-03-22 22:23:40 +1100 | [diff] [blame] | 2142 | * We hold a reference to 'inode' so it couldn't have been |
| 2143 | * removed from s_inodes list while we dropped the |
Dave Chinner | 74278da | 2015-03-04 12:37:22 -0500 | [diff] [blame] | 2144 | * s_inode_list_lock. We cannot iput the inode now as we can |
Dave Chinner | 55fa609 | 2011-03-22 22:23:40 +1100 | [diff] [blame] | 2145 | * be holding the last reference and we cannot iput it under |
Dave Chinner | 74278da | 2015-03-04 12:37:22 -0500 | [diff] [blame] | 2146 | * s_inode_list_lock. So we keep the reference and iput it |
Dave Chinner | 55fa609 | 2011-03-22 22:23:40 +1100 | [diff] [blame] | 2147 | * later. |
Jens Axboe | 03ba378 | 2009-09-09 09:08:54 +0200 | [diff] [blame] | 2148 | */ |
| 2149 | iput(old_inode); |
| 2150 | old_inode = inode; |
| 2151 | |
| 2152 | filemap_fdatawait(mapping); |
| 2153 | |
| 2154 | cond_resched(); |
Nick Piggin | 38f2197 | 2009-01-06 14:40:25 -0800 | [diff] [blame] | 2155 | |
Dave Chinner | 74278da | 2015-03-04 12:37:22 -0500 | [diff] [blame] | 2156 | spin_lock(&sb->s_inode_list_lock); |
Jens Axboe | 66f3b8e | 2009-09-02 09:19:46 +0200 | [diff] [blame] | 2157 | } |
Dave Chinner | 74278da | 2015-03-04 12:37:22 -0500 | [diff] [blame] | 2158 | spin_unlock(&sb->s_inode_list_lock); |
Jens Axboe | 03ba378 | 2009-09-09 09:08:54 +0200 | [diff] [blame] | 2159 | iput(old_inode); |
Dave Chinner | e97fedb | 2015-03-04 13:40:00 -0500 | [diff] [blame] | 2160 | mutex_unlock(&sb->s_sync_lock); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2161 | } |
| 2162 | |
Tejun Heo | f30a7d0 | 2015-05-22 17:14:00 -0400 | [diff] [blame] | 2163 | static void __writeback_inodes_sb_nr(struct super_block *sb, unsigned long nr, |
| 2164 | enum wb_reason reason, bool skip_if_busy) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2165 | { |
Tejun Heo | cc395d7 | 2015-05-22 17:13:58 -0400 | [diff] [blame] | 2166 | DEFINE_WB_COMPLETION_ONSTACK(done); |
Christoph Hellwig | 83ba7b0 | 2010-07-06 08:59:53 +0200 | [diff] [blame] | 2167 | struct wb_writeback_work work = { |
Wu Fengguang | 6e6938b | 2010-06-06 10:38:15 -0600 | [diff] [blame] | 2168 | .sb = sb, |
| 2169 | .sync_mode = WB_SYNC_NONE, |
| 2170 | .tagged_writepages = 1, |
| 2171 | .done = &done, |
| 2172 | .nr_pages = nr, |
Curt Wohlgemuth | 0e175a1 | 2011-10-07 21:54:10 -0600 | [diff] [blame] | 2173 | .reason = reason, |
Christoph Hellwig | 3c4d716 | 2010-06-08 18:14:43 +0200 | [diff] [blame] | 2174 | }; |
Tejun Heo | e797291 | 2015-05-22 17:13:48 -0400 | [diff] [blame] | 2175 | struct backing_dev_info *bdi = sb->s_bdi; |
Jens Axboe | 0e3c9a2 | 2010-06-01 11:08:43 +0200 | [diff] [blame] | 2176 | |
Tejun Heo | e797291 | 2015-05-22 17:13:48 -0400 | [diff] [blame] | 2177 | if (!bdi_has_dirty_io(bdi) || bdi == &noop_backing_dev_info) |
Jan Kara | 6eedc70 | 2012-07-03 16:45:27 +0200 | [diff] [blame] | 2178 | return; |
Christoph Hellwig | cf37e97 | 2010-06-08 18:14:51 +0200 | [diff] [blame] | 2179 | WARN_ON(!rwsem_is_locked(&sb->s_umount)); |
Tejun Heo | f30a7d0 | 2015-05-22 17:14:00 -0400 | [diff] [blame] | 2180 | |
Tejun Heo | db12536 | 2015-05-22 17:14:01 -0400 | [diff] [blame] | 2181 | bdi_split_work_to_wbs(sb->s_bdi, &work, skip_if_busy); |
Tejun Heo | cc395d7 | 2015-05-22 17:13:58 -0400 | [diff] [blame] | 2182 | wb_wait_for_completion(bdi, &done); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2183 | } |
Tejun Heo | f30a7d0 | 2015-05-22 17:14:00 -0400 | [diff] [blame] | 2184 | |
| 2185 | /** |
| 2186 | * writeback_inodes_sb_nr - writeback dirty inodes from given super_block |
| 2187 | * @sb: the superblock |
| 2188 | * @nr: the number of pages to write |
| 2189 | * @reason: reason why some writeback work initiated |
| 2190 | * |
| 2191 | * Start writeback on some inodes on this super_block. No guarantees are made |
| 2192 | * on how many (if any) will be written, and this function does not wait |
| 2193 | * for IO completion of submitted IO. |
| 2194 | */ |
| 2195 | void writeback_inodes_sb_nr(struct super_block *sb, |
| 2196 | unsigned long nr, |
| 2197 | enum wb_reason reason) |
| 2198 | { |
| 2199 | __writeback_inodes_sb_nr(sb, nr, reason, false); |
| 2200 | } |
Chris Mason | 3259f8b | 2010-10-29 11:16:17 -0400 | [diff] [blame] | 2201 | EXPORT_SYMBOL(writeback_inodes_sb_nr); |
| 2202 | |
| 2203 | /** |
| 2204 | * writeback_inodes_sb - writeback dirty inodes from given super_block |
| 2205 | * @sb: the superblock |
Marcos Paulo de Souza | 786228a | 2011-11-23 20:56:45 +0800 | [diff] [blame] | 2206 | * @reason: reason why some writeback work was initiated |
Chris Mason | 3259f8b | 2010-10-29 11:16:17 -0400 | [diff] [blame] | 2207 | * |
| 2208 | * Start writeback on some inodes on this super_block. No guarantees are made |
| 2209 | * on how many (if any) will be written, and this function does not wait |
| 2210 | * for IO completion of submitted IO. |
| 2211 | */ |
Curt Wohlgemuth | 0e175a1 | 2011-10-07 21:54:10 -0600 | [diff] [blame] | 2212 | void writeback_inodes_sb(struct super_block *sb, enum wb_reason reason) |
Chris Mason | 3259f8b | 2010-10-29 11:16:17 -0400 | [diff] [blame] | 2213 | { |
Curt Wohlgemuth | 0e175a1 | 2011-10-07 21:54:10 -0600 | [diff] [blame] | 2214 | return writeback_inodes_sb_nr(sb, get_nr_dirty_pages(), reason); |
Chris Mason | 3259f8b | 2010-10-29 11:16:17 -0400 | [diff] [blame] | 2215 | } |
Jens Axboe | d8a8559 | 2009-09-02 12:34:32 +0200 | [diff] [blame] | 2216 | EXPORT_SYMBOL(writeback_inodes_sb); |
| 2217 | |
| 2218 | /** |
Miao Xie | 10ee27a | 2013-01-10 13:47:57 +0800 | [diff] [blame] | 2219 | * try_to_writeback_inodes_sb_nr - try to start writeback if none underway |
Chris Mason | 3259f8b | 2010-10-29 11:16:17 -0400 | [diff] [blame] | 2220 | * @sb: the superblock |
| 2221 | * @nr: the number of pages to write |
Miao Xie | 10ee27a | 2013-01-10 13:47:57 +0800 | [diff] [blame] | 2222 | * @reason: the reason of writeback |
Chris Mason | 3259f8b | 2010-10-29 11:16:17 -0400 | [diff] [blame] | 2223 | * |
Miao Xie | 10ee27a | 2013-01-10 13:47:57 +0800 | [diff] [blame] | 2224 | * Invoke writeback_inodes_sb_nr if no writeback is currently underway. |
Chris Mason | 3259f8b | 2010-10-29 11:16:17 -0400 | [diff] [blame] | 2225 | * Returns 1 if writeback was started, 0 if not. |
| 2226 | */ |
Tejun Heo | f30a7d0 | 2015-05-22 17:14:00 -0400 | [diff] [blame] | 2227 | bool try_to_writeback_inodes_sb_nr(struct super_block *sb, unsigned long nr, |
| 2228 | enum wb_reason reason) |
Chris Mason | 3259f8b | 2010-10-29 11:16:17 -0400 | [diff] [blame] | 2229 | { |
Miao Xie | 10ee27a | 2013-01-10 13:47:57 +0800 | [diff] [blame] | 2230 | if (!down_read_trylock(&sb->s_umount)) |
Tejun Heo | f30a7d0 | 2015-05-22 17:14:00 -0400 | [diff] [blame] | 2231 | return false; |
Miao Xie | 10ee27a | 2013-01-10 13:47:57 +0800 | [diff] [blame] | 2232 | |
Tejun Heo | f30a7d0 | 2015-05-22 17:14:00 -0400 | [diff] [blame] | 2233 | __writeback_inodes_sb_nr(sb, nr, reason, true); |
Miao Xie | 10ee27a | 2013-01-10 13:47:57 +0800 | [diff] [blame] | 2234 | up_read(&sb->s_umount); |
Tejun Heo | f30a7d0 | 2015-05-22 17:14:00 -0400 | [diff] [blame] | 2235 | return true; |
Chris Mason | 3259f8b | 2010-10-29 11:16:17 -0400 | [diff] [blame] | 2236 | } |
Miao Xie | 10ee27a | 2013-01-10 13:47:57 +0800 | [diff] [blame] | 2237 | EXPORT_SYMBOL(try_to_writeback_inodes_sb_nr); |
| 2238 | |
| 2239 | /** |
| 2240 | * try_to_writeback_inodes_sb - try to start writeback if none underway |
| 2241 | * @sb: the superblock |
| 2242 | * @reason: reason why some writeback work was initiated |
| 2243 | * |
| 2244 | * Implement by try_to_writeback_inodes_sb_nr() |
| 2245 | * Returns 1 if writeback was started, 0 if not. |
| 2246 | */ |
Tejun Heo | f30a7d0 | 2015-05-22 17:14:00 -0400 | [diff] [blame] | 2247 | bool try_to_writeback_inodes_sb(struct super_block *sb, enum wb_reason reason) |
Miao Xie | 10ee27a | 2013-01-10 13:47:57 +0800 | [diff] [blame] | 2248 | { |
| 2249 | return try_to_writeback_inodes_sb_nr(sb, get_nr_dirty_pages(), reason); |
| 2250 | } |
| 2251 | EXPORT_SYMBOL(try_to_writeback_inodes_sb); |
Chris Mason | 3259f8b | 2010-10-29 11:16:17 -0400 | [diff] [blame] | 2252 | |
| 2253 | /** |
Jens Axboe | d8a8559 | 2009-09-02 12:34:32 +0200 | [diff] [blame] | 2254 | * sync_inodes_sb - sync sb inode pages |
Jan Kara | 0dc83bd | 2014-02-21 11:19:04 +0100 | [diff] [blame] | 2255 | * @sb: the superblock |
Jens Axboe | d8a8559 | 2009-09-02 12:34:32 +0200 | [diff] [blame] | 2256 | * |
| 2257 | * This function writes and waits on any dirty inode belonging to this |
Jan Kara | 0dc83bd | 2014-02-21 11:19:04 +0100 | [diff] [blame] | 2258 | * super_block. |
Jens Axboe | d8a8559 | 2009-09-02 12:34:32 +0200 | [diff] [blame] | 2259 | */ |
Jan Kara | 0dc83bd | 2014-02-21 11:19:04 +0100 | [diff] [blame] | 2260 | void sync_inodes_sb(struct super_block *sb) |
Jens Axboe | d8a8559 | 2009-09-02 12:34:32 +0200 | [diff] [blame] | 2261 | { |
Tejun Heo | cc395d7 | 2015-05-22 17:13:58 -0400 | [diff] [blame] | 2262 | DEFINE_WB_COMPLETION_ONSTACK(done); |
Christoph Hellwig | 83ba7b0 | 2010-07-06 08:59:53 +0200 | [diff] [blame] | 2263 | struct wb_writeback_work work = { |
Christoph Hellwig | 3c4d716 | 2010-06-08 18:14:43 +0200 | [diff] [blame] | 2264 | .sb = sb, |
| 2265 | .sync_mode = WB_SYNC_ALL, |
| 2266 | .nr_pages = LONG_MAX, |
| 2267 | .range_cyclic = 0, |
Christoph Hellwig | 83ba7b0 | 2010-07-06 08:59:53 +0200 | [diff] [blame] | 2268 | .done = &done, |
Curt Wohlgemuth | 0e175a1 | 2011-10-07 21:54:10 -0600 | [diff] [blame] | 2269 | .reason = WB_REASON_SYNC, |
Dave Chinner | 7747bd4 | 2013-07-02 22:38:35 +1000 | [diff] [blame] | 2270 | .for_sync = 1, |
Christoph Hellwig | 3c4d716 | 2010-06-08 18:14:43 +0200 | [diff] [blame] | 2271 | }; |
Tejun Heo | e797291 | 2015-05-22 17:13:48 -0400 | [diff] [blame] | 2272 | struct backing_dev_info *bdi = sb->s_bdi; |
Christoph Hellwig | 3c4d716 | 2010-06-08 18:14:43 +0200 | [diff] [blame] | 2273 | |
Tejun Heo | 006a097 | 2015-08-25 14:11:52 -0400 | [diff] [blame] | 2274 | /* |
| 2275 | * Can't skip on !bdi_has_dirty() because we should wait for !dirty |
| 2276 | * inodes under writeback and I_DIRTY_TIME inodes ignored by |
| 2277 | * bdi_has_dirty() need to be written out too. |
| 2278 | */ |
| 2279 | if (bdi == &noop_backing_dev_info) |
Jan Kara | 6eedc70 | 2012-07-03 16:45:27 +0200 | [diff] [blame] | 2280 | return; |
Christoph Hellwig | cf37e97 | 2010-06-08 18:14:51 +0200 | [diff] [blame] | 2281 | WARN_ON(!rwsem_is_locked(&sb->s_umount)); |
| 2282 | |
Tejun Heo | db12536 | 2015-05-22 17:14:01 -0400 | [diff] [blame] | 2283 | bdi_split_work_to_wbs(bdi, &work, false); |
Tejun Heo | cc395d7 | 2015-05-22 17:13:58 -0400 | [diff] [blame] | 2284 | wb_wait_for_completion(bdi, &done); |
Christoph Hellwig | 83ba7b0 | 2010-07-06 08:59:53 +0200 | [diff] [blame] | 2285 | |
Jens Axboe | b6e5131 | 2009-09-16 15:13:54 +0200 | [diff] [blame] | 2286 | wait_sb_inodes(sb); |
Jens Axboe | d8a8559 | 2009-09-02 12:34:32 +0200 | [diff] [blame] | 2287 | } |
| 2288 | EXPORT_SYMBOL(sync_inodes_sb); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2289 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2290 | /** |
Andrea Arcangeli | 7f04c26 | 2005-10-30 15:03:05 -0800 | [diff] [blame] | 2291 | * write_inode_now - write an inode to disk |
| 2292 | * @inode: inode to write to disk |
| 2293 | * @sync: whether the write should be synchronous or not |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2294 | * |
Andrea Arcangeli | 7f04c26 | 2005-10-30 15:03:05 -0800 | [diff] [blame] | 2295 | * This function commits an inode to disk immediately if it is dirty. This is |
| 2296 | * primarily needed by knfsd. |
| 2297 | * |
| 2298 | * 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] | 2299 | */ |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2300 | int write_inode_now(struct inode *inode, int sync) |
| 2301 | { |
Christoph Hellwig | f758eea | 2011-04-21 18:19:44 -0600 | [diff] [blame] | 2302 | struct bdi_writeback *wb = &inode_to_bdi(inode)->wb; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2303 | struct writeback_control wbc = { |
| 2304 | .nr_to_write = LONG_MAX, |
Mike Galbraith | 18914b1 | 2008-02-08 04:20:23 -0800 | [diff] [blame] | 2305 | .sync_mode = sync ? WB_SYNC_ALL : WB_SYNC_NONE, |
OGAWA Hirofumi | 111ebb6 | 2006-06-23 02:03:26 -0700 | [diff] [blame] | 2306 | .range_start = 0, |
| 2307 | .range_end = LLONG_MAX, |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2308 | }; |
| 2309 | |
| 2310 | if (!mapping_cap_writeback_dirty(inode->i_mapping)) |
Andrew Morton | 49364ce | 2005-11-07 00:59:15 -0800 | [diff] [blame] | 2311 | wbc.nr_to_write = 0; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2312 | |
| 2313 | might_sleep(); |
Jan Kara | 4f8ad65 | 2012-05-03 14:48:00 +0200 | [diff] [blame] | 2314 | return writeback_single_inode(inode, wb, &wbc); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2315 | } |
| 2316 | EXPORT_SYMBOL(write_inode_now); |
| 2317 | |
| 2318 | /** |
| 2319 | * sync_inode - write an inode and its pages to disk. |
| 2320 | * @inode: the inode to sync |
| 2321 | * @wbc: controls the writeback mode |
| 2322 | * |
| 2323 | * sync_inode() will write an inode and its pages to disk. It will also |
| 2324 | * correctly update the inode on its superblock's dirty inode lists and will |
| 2325 | * update inode->i_state. |
| 2326 | * |
| 2327 | * The caller must have a ref on the inode. |
| 2328 | */ |
| 2329 | int sync_inode(struct inode *inode, struct writeback_control *wbc) |
| 2330 | { |
Jan Kara | 4f8ad65 | 2012-05-03 14:48:00 +0200 | [diff] [blame] | 2331 | return writeback_single_inode(inode, &inode_to_bdi(inode)->wb, wbc); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2332 | } |
| 2333 | EXPORT_SYMBOL(sync_inode); |
Christoph Hellwig | c3765016 | 2010-10-06 10:48:20 +0200 | [diff] [blame] | 2334 | |
| 2335 | /** |
Andrew Morton | c691b9d | 2011-01-13 15:45:48 -0800 | [diff] [blame] | 2336 | * sync_inode_metadata - write an inode to disk |
Christoph Hellwig | c3765016 | 2010-10-06 10:48:20 +0200 | [diff] [blame] | 2337 | * @inode: the inode to sync |
| 2338 | * @wait: wait for I/O to complete. |
| 2339 | * |
Andrew Morton | c691b9d | 2011-01-13 15:45:48 -0800 | [diff] [blame] | 2340 | * Write an inode to disk and adjust its dirty state after completion. |
Christoph Hellwig | c3765016 | 2010-10-06 10:48:20 +0200 | [diff] [blame] | 2341 | * |
| 2342 | * Note: only writes the actual inode, no associated data or other metadata. |
| 2343 | */ |
| 2344 | int sync_inode_metadata(struct inode *inode, int wait) |
| 2345 | { |
| 2346 | struct writeback_control wbc = { |
| 2347 | .sync_mode = wait ? WB_SYNC_ALL : WB_SYNC_NONE, |
| 2348 | .nr_to_write = 0, /* metadata-only */ |
| 2349 | }; |
| 2350 | |
| 2351 | return sync_inode(inode, &wbc); |
| 2352 | } |
| 2353 | EXPORT_SYMBOL(sync_inode_metadata); |