Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1 | /* |
| 2 | * fs/fs-writeback.c |
| 3 | * |
| 4 | * Copyright (C) 2002, Linus Torvalds. |
| 5 | * |
| 6 | * Contains all the functions related to writing back and waiting |
| 7 | * upon dirty inodes against superblocks, and writing back dirty |
| 8 | * pages against inodes. ie: data writeback. Writeout of the |
| 9 | * inode itself is not handled here. |
| 10 | * |
Francois Cami | e1f8e87 | 2008-10-15 22:01:59 -0700 | [diff] [blame] | 11 | * 10Apr2002 Andrew Morton |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 12 | * Split out of fs/inode.c |
| 13 | * Additions for address_space-based writeback |
| 14 | */ |
| 15 | |
| 16 | #include <linux/kernel.h> |
Jens Axboe | f5ff842 | 2007-09-21 09:19:54 +0200 | [diff] [blame] | 17 | #include <linux/module.h> |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 18 | #include <linux/spinlock.h> |
Tejun Heo | 5a0e3ad | 2010-03-24 17:04:11 +0900 | [diff] [blame] | 19 | #include <linux/slab.h> |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 20 | #include <linux/sched.h> |
| 21 | #include <linux/fs.h> |
| 22 | #include <linux/mm.h> |
Jens Axboe | 03ba378 | 2009-09-09 09:08:54 +0200 | [diff] [blame] | 23 | #include <linux/kthread.h> |
| 24 | #include <linux/freezer.h> |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 25 | #include <linux/writeback.h> |
| 26 | #include <linux/blkdev.h> |
| 27 | #include <linux/backing-dev.h> |
| 28 | #include <linux/buffer_head.h> |
David Howells | 07f3f05 | 2006-09-30 20:52:18 +0200 | [diff] [blame] | 29 | #include "internal.h" |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 30 | |
Jens Axboe | 66f3b8e | 2009-09-02 09:19:46 +0200 | [diff] [blame] | 31 | #define inode_to_bdi(inode) ((inode)->i_mapping->backing_dev_info) |
Adrian Bunk | f11b00f | 2008-04-29 00:58:56 -0700 | [diff] [blame] | 32 | |
Jens Axboe | 03ba378 | 2009-09-09 09:08:54 +0200 | [diff] [blame] | 33 | /* |
Jens Axboe | d0bceac | 2009-05-18 08:20:32 +0200 | [diff] [blame] | 34 | * We don't actually have pdflush, but this one is exported though /proc... |
| 35 | */ |
| 36 | int nr_pdflush_threads; |
| 37 | |
| 38 | /* |
Jens Axboe | c4a77a6 | 2009-09-16 15:18:25 +0200 | [diff] [blame] | 39 | * Passed into wb_writeback(), essentially a subset of writeback_control |
| 40 | */ |
Christoph Hellwig | 83ba7b0 | 2010-07-06 08:59:53 +0200 | [diff] [blame] | 41 | struct wb_writeback_work { |
Jens Axboe | c4a77a6 | 2009-09-16 15:18:25 +0200 | [diff] [blame] | 42 | long nr_pages; |
| 43 | struct super_block *sb; |
| 44 | enum writeback_sync_modes sync_mode; |
H Hartley Sweeten | 52957fe | 2010-04-01 20:36:30 -0500 | [diff] [blame] | 45 | unsigned int for_kupdate:1; |
| 46 | unsigned int range_cyclic:1; |
| 47 | unsigned int for_background:1; |
Jens Axboe | c4a77a6 | 2009-09-16 15:18:25 +0200 | [diff] [blame] | 48 | |
Jens Axboe | 8010c3b | 2009-09-15 20:04:57 +0200 | [diff] [blame] | 49 | struct list_head list; /* pending work list */ |
Christoph Hellwig | 83ba7b0 | 2010-07-06 08:59:53 +0200 | [diff] [blame] | 50 | struct completion *done; /* set if the caller waits */ |
Jens Axboe | 03ba378 | 2009-09-09 09:08:54 +0200 | [diff] [blame] | 51 | }; |
| 52 | |
Adrian Bunk | f11b00f | 2008-04-29 00:58:56 -0700 | [diff] [blame] | 53 | /** |
| 54 | * writeback_in_progress - determine whether there is writeback in progress |
| 55 | * @bdi: the device's backing_dev_info structure. |
| 56 | * |
Jens Axboe | 03ba378 | 2009-09-09 09:08:54 +0200 | [diff] [blame] | 57 | * Determine whether there is writeback waiting to be handled against a |
| 58 | * backing device. |
Adrian Bunk | f11b00f | 2008-04-29 00:58:56 -0700 | [diff] [blame] | 59 | */ |
| 60 | int writeback_in_progress(struct backing_dev_info *bdi) |
| 61 | { |
Jens Axboe | 03ba378 | 2009-09-09 09:08:54 +0200 | [diff] [blame] | 62 | return !list_empty(&bdi->work_list); |
Adrian Bunk | f11b00f | 2008-04-29 00:58:56 -0700 | [diff] [blame] | 63 | } |
| 64 | |
Christoph Hellwig | 83ba7b0 | 2010-07-06 08:59:53 +0200 | [diff] [blame] | 65 | static void bdi_queue_work(struct backing_dev_info *bdi, |
| 66 | struct wb_writeback_work *work) |
Nick Piggin | 4195f73 | 2009-05-28 09:01:15 +0200 | [diff] [blame] | 67 | { |
Jens Axboe | bcddc3f | 2009-09-13 20:07:36 +0200 | [diff] [blame] | 68 | spin_lock(&bdi->wb_lock); |
Christoph Hellwig | 83ba7b0 | 2010-07-06 08:59:53 +0200 | [diff] [blame] | 69 | list_add_tail(&work->list, &bdi->work_list); |
Jens Axboe | bcddc3f | 2009-09-13 20:07:36 +0200 | [diff] [blame] | 70 | spin_unlock(&bdi->wb_lock); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 71 | |
| 72 | /* |
Jens Axboe | 03ba378 | 2009-09-09 09:08:54 +0200 | [diff] [blame] | 73 | * If the default thread isn't there, make sure we add it. When |
| 74 | * it gets created and wakes up, we'll run this work. |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 75 | */ |
Jens Axboe | 03ba378 | 2009-09-09 09:08:54 +0200 | [diff] [blame] | 76 | if (unlikely(list_empty_careful(&bdi->wb_list))) |
| 77 | wake_up_process(default_backing_dev_info.wb.task); |
| 78 | else { |
| 79 | struct bdi_writeback *wb = &bdi->wb; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 80 | |
Nick Piggin | 1ef7d9a | 2009-09-15 21:37:55 +0200 | [diff] [blame] | 81 | if (wb->task) |
Jens Axboe | 03ba378 | 2009-09-09 09:08:54 +0200 | [diff] [blame] | 82 | wake_up_process(wb->task); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 83 | } |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 84 | } |
| 85 | |
Christoph Hellwig | 83ba7b0 | 2010-07-06 08:59:53 +0200 | [diff] [blame] | 86 | static void |
| 87 | __bdi_start_writeback(struct backing_dev_info *bdi, long nr_pages, |
| 88 | bool range_cyclic, bool for_background) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 89 | { |
Christoph Hellwig | 83ba7b0 | 2010-07-06 08:59:53 +0200 | [diff] [blame] | 90 | struct wb_writeback_work *work; |
Jens Axboe | 03ba378 | 2009-09-09 09:08:54 +0200 | [diff] [blame] | 91 | |
Jens Axboe | bcddc3f | 2009-09-13 20:07:36 +0200 | [diff] [blame] | 92 | /* |
| 93 | * This is WB_SYNC_NONE writeback, so if allocation fails just |
| 94 | * wakeup the thread for old dirty data writeback |
| 95 | */ |
Christoph Hellwig | 83ba7b0 | 2010-07-06 08:59:53 +0200 | [diff] [blame] | 96 | work = kzalloc(sizeof(*work), GFP_ATOMIC); |
| 97 | if (!work) { |
| 98 | if (bdi->wb.task) |
| 99 | wake_up_process(bdi->wb.task); |
| 100 | return; |
Jens Axboe | bcddc3f | 2009-09-13 20:07:36 +0200 | [diff] [blame] | 101 | } |
Jens Axboe | 03ba378 | 2009-09-09 09:08:54 +0200 | [diff] [blame] | 102 | |
Christoph Hellwig | 83ba7b0 | 2010-07-06 08:59:53 +0200 | [diff] [blame] | 103 | work->sync_mode = WB_SYNC_NONE; |
| 104 | work->nr_pages = nr_pages; |
| 105 | work->range_cyclic = range_cyclic; |
| 106 | work->for_background = for_background; |
Christoph Hellwig | f0fad8a | 2009-09-11 09:47:56 +0200 | [diff] [blame] | 107 | |
Christoph Hellwig | 83ba7b0 | 2010-07-06 08:59:53 +0200 | [diff] [blame] | 108 | bdi_queue_work(bdi, work); |
Jens Axboe | b6e5131 | 2009-09-16 15:13:54 +0200 | [diff] [blame] | 109 | } |
| 110 | |
| 111 | /** |
| 112 | * bdi_start_writeback - start writeback |
| 113 | * @bdi: the backing device to write from |
| 114 | * @nr_pages: the number of pages to write |
| 115 | * |
| 116 | * Description: |
| 117 | * This does WB_SYNC_NONE opportunistic writeback. The IO is only |
| 118 | * started when this function returns, we make no guarentees on |
Jens Axboe | 0e3c9a2 | 2010-06-01 11:08:43 +0200 | [diff] [blame] | 119 | * completion. Caller need not hold sb s_umount semaphore. |
Jens Axboe | b6e5131 | 2009-09-16 15:13:54 +0200 | [diff] [blame] | 120 | * |
| 121 | */ |
Christoph Hellwig | c544419 | 2010-06-08 18:15:15 +0200 | [diff] [blame] | 122 | void bdi_start_writeback(struct backing_dev_info *bdi, long nr_pages) |
Jens Axboe | b6e5131 | 2009-09-16 15:13:54 +0200 | [diff] [blame] | 123 | { |
Christoph Hellwig | 83ba7b0 | 2010-07-06 08:59:53 +0200 | [diff] [blame] | 124 | __bdi_start_writeback(bdi, nr_pages, true, false); |
Christoph Hellwig | c544419 | 2010-06-08 18:15:15 +0200 | [diff] [blame] | 125 | } |
Wu Fengguang | d3ddec7 | 2009-09-23 20:33:40 +0800 | [diff] [blame] | 126 | |
Christoph Hellwig | c544419 | 2010-06-08 18:15:15 +0200 | [diff] [blame] | 127 | /** |
| 128 | * bdi_start_background_writeback - start background writeback |
| 129 | * @bdi: the backing device to write from |
| 130 | * |
| 131 | * Description: |
| 132 | * This does WB_SYNC_NONE background writeback. The IO is only |
| 133 | * started when this function returns, we make no guarentees on |
| 134 | * completion. Caller need not hold sb s_umount semaphore. |
| 135 | */ |
| 136 | void bdi_start_background_writeback(struct backing_dev_info *bdi) |
| 137 | { |
Christoph Hellwig | 83ba7b0 | 2010-07-06 08:59:53 +0200 | [diff] [blame] | 138 | __bdi_start_writeback(bdi, LONG_MAX, true, true); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 139 | } |
| 140 | |
| 141 | /* |
Andrew Morton | 6610a0b | 2007-10-16 23:30:32 -0700 | [diff] [blame] | 142 | * Redirty an inode: set its when-it-was dirtied timestamp and move it to the |
| 143 | * furthest end of its superblock's dirty-inode list. |
| 144 | * |
| 145 | * 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] | 146 | * 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] | 147 | * the case then the inode must have been redirtied while it was being written |
| 148 | * out and we don't reset its dirtied_when. |
| 149 | */ |
| 150 | static void redirty_tail(struct inode *inode) |
| 151 | { |
Jens Axboe | 03ba378 | 2009-09-09 09:08:54 +0200 | [diff] [blame] | 152 | struct bdi_writeback *wb = &inode_to_bdi(inode)->wb; |
Andrew Morton | 6610a0b | 2007-10-16 23:30:32 -0700 | [diff] [blame] | 153 | |
Jens Axboe | 03ba378 | 2009-09-09 09:08:54 +0200 | [diff] [blame] | 154 | if (!list_empty(&wb->b_dirty)) { |
Jens Axboe | 66f3b8e | 2009-09-02 09:19:46 +0200 | [diff] [blame] | 155 | struct inode *tail; |
Andrew Morton | 6610a0b | 2007-10-16 23:30:32 -0700 | [diff] [blame] | 156 | |
Jens Axboe | 03ba378 | 2009-09-09 09:08:54 +0200 | [diff] [blame] | 157 | tail = list_entry(wb->b_dirty.next, struct inode, i_list); |
Jens Axboe | 66f3b8e | 2009-09-02 09:19:46 +0200 | [diff] [blame] | 158 | if (time_before(inode->dirtied_when, tail->dirtied_when)) |
Andrew Morton | 6610a0b | 2007-10-16 23:30:32 -0700 | [diff] [blame] | 159 | inode->dirtied_when = jiffies; |
| 160 | } |
Jens Axboe | 03ba378 | 2009-09-09 09:08:54 +0200 | [diff] [blame] | 161 | list_move(&inode->i_list, &wb->b_dirty); |
Andrew Morton | 6610a0b | 2007-10-16 23:30:32 -0700 | [diff] [blame] | 162 | } |
| 163 | |
| 164 | /* |
Jens Axboe | 66f3b8e | 2009-09-02 09:19:46 +0200 | [diff] [blame] | 165 | * requeue inode for re-scanning after bdi->b_io list is exhausted. |
Andrew Morton | c986d1e | 2007-10-16 23:30:34 -0700 | [diff] [blame] | 166 | */ |
Ken Chen | 0e0f4fc | 2007-10-16 23:30:38 -0700 | [diff] [blame] | 167 | static void requeue_io(struct inode *inode) |
Andrew Morton | c986d1e | 2007-10-16 23:30:34 -0700 | [diff] [blame] | 168 | { |
Jens Axboe | 03ba378 | 2009-09-09 09:08:54 +0200 | [diff] [blame] | 169 | struct bdi_writeback *wb = &inode_to_bdi(inode)->wb; |
| 170 | |
| 171 | list_move(&inode->i_list, &wb->b_more_io); |
Andrew Morton | c986d1e | 2007-10-16 23:30:34 -0700 | [diff] [blame] | 172 | } |
| 173 | |
Joern Engel | 1c0eeaf | 2007-10-16 23:30:44 -0700 | [diff] [blame] | 174 | static void inode_sync_complete(struct inode *inode) |
| 175 | { |
| 176 | /* |
| 177 | * Prevent speculative execution through spin_unlock(&inode_lock); |
| 178 | */ |
| 179 | smp_mb(); |
| 180 | wake_up_bit(&inode->i_state, __I_SYNC); |
| 181 | } |
| 182 | |
Jeff Layton | d2caa3c | 2009-04-02 16:56:37 -0700 | [diff] [blame] | 183 | static bool inode_dirtied_after(struct inode *inode, unsigned long t) |
| 184 | { |
| 185 | bool ret = time_after(inode->dirtied_when, t); |
| 186 | #ifndef CONFIG_64BIT |
| 187 | /* |
| 188 | * For inodes being constantly redirtied, dirtied_when can get stuck. |
| 189 | * It _appears_ to be in the future, but is actually in distant past. |
| 190 | * This test is necessary to prevent such wrapped-around relative times |
Jens Axboe | 5b0830c | 2009-09-23 19:37:09 +0200 | [diff] [blame] | 191 | * from permanently stopping the whole bdi writeback. |
Jeff Layton | d2caa3c | 2009-04-02 16:56:37 -0700 | [diff] [blame] | 192 | */ |
| 193 | ret = ret && time_before_eq(inode->dirtied_when, jiffies); |
| 194 | #endif |
| 195 | return ret; |
| 196 | } |
| 197 | |
Andrew Morton | c986d1e | 2007-10-16 23:30:34 -0700 | [diff] [blame] | 198 | /* |
Fengguang Wu | 2c13657 | 2007-10-16 23:30:39 -0700 | [diff] [blame] | 199 | * Move expired dirty inodes from @delaying_queue to @dispatch_queue. |
| 200 | */ |
| 201 | static void move_expired_inodes(struct list_head *delaying_queue, |
| 202 | struct list_head *dispatch_queue, |
| 203 | unsigned long *older_than_this) |
| 204 | { |
Shaohua Li | 5c03449 | 2009-09-24 14:42:33 +0200 | [diff] [blame] | 205 | LIST_HEAD(tmp); |
| 206 | struct list_head *pos, *node; |
Jens Axboe | cf13730 | 2009-09-24 15:12:57 +0200 | [diff] [blame] | 207 | struct super_block *sb = NULL; |
Shaohua Li | 5c03449 | 2009-09-24 14:42:33 +0200 | [diff] [blame] | 208 | struct inode *inode; |
Jens Axboe | cf13730 | 2009-09-24 15:12:57 +0200 | [diff] [blame] | 209 | int do_sb_sort = 0; |
Shaohua Li | 5c03449 | 2009-09-24 14:42:33 +0200 | [diff] [blame] | 210 | |
Fengguang Wu | 2c13657 | 2007-10-16 23:30:39 -0700 | [diff] [blame] | 211 | while (!list_empty(delaying_queue)) { |
Shaohua Li | 5c03449 | 2009-09-24 14:42:33 +0200 | [diff] [blame] | 212 | inode = list_entry(delaying_queue->prev, struct inode, i_list); |
Fengguang Wu | 2c13657 | 2007-10-16 23:30:39 -0700 | [diff] [blame] | 213 | if (older_than_this && |
Jeff Layton | d2caa3c | 2009-04-02 16:56:37 -0700 | [diff] [blame] | 214 | inode_dirtied_after(inode, *older_than_this)) |
Fengguang Wu | 2c13657 | 2007-10-16 23:30:39 -0700 | [diff] [blame] | 215 | break; |
Jens Axboe | cf13730 | 2009-09-24 15:12:57 +0200 | [diff] [blame] | 216 | if (sb && sb != inode->i_sb) |
| 217 | do_sb_sort = 1; |
| 218 | sb = inode->i_sb; |
Shaohua Li | 5c03449 | 2009-09-24 14:42:33 +0200 | [diff] [blame] | 219 | list_move(&inode->i_list, &tmp); |
| 220 | } |
| 221 | |
Jens Axboe | cf13730 | 2009-09-24 15:12:57 +0200 | [diff] [blame] | 222 | /* just one sb in list, splice to dispatch_queue and we're done */ |
| 223 | if (!do_sb_sort) { |
| 224 | list_splice(&tmp, dispatch_queue); |
| 225 | return; |
| 226 | } |
| 227 | |
Shaohua Li | 5c03449 | 2009-09-24 14:42:33 +0200 | [diff] [blame] | 228 | /* Move inodes from one superblock together */ |
| 229 | while (!list_empty(&tmp)) { |
| 230 | inode = list_entry(tmp.prev, struct inode, i_list); |
| 231 | sb = inode->i_sb; |
| 232 | list_for_each_prev_safe(pos, node, &tmp) { |
| 233 | inode = list_entry(pos, struct inode, i_list); |
| 234 | if (inode->i_sb == sb) |
| 235 | list_move(&inode->i_list, dispatch_queue); |
| 236 | } |
Fengguang Wu | 2c13657 | 2007-10-16 23:30:39 -0700 | [diff] [blame] | 237 | } |
| 238 | } |
| 239 | |
| 240 | /* |
| 241 | * Queue all expired dirty inodes for io, eldest first. |
| 242 | */ |
Jens Axboe | 03ba378 | 2009-09-09 09:08:54 +0200 | [diff] [blame] | 243 | static void queue_io(struct bdi_writeback *wb, unsigned long *older_than_this) |
Fengguang Wu | 2c13657 | 2007-10-16 23:30:39 -0700 | [diff] [blame] | 244 | { |
Jens Axboe | 03ba378 | 2009-09-09 09:08:54 +0200 | [diff] [blame] | 245 | list_splice_init(&wb->b_more_io, wb->b_io.prev); |
| 246 | move_expired_inodes(&wb->b_dirty, &wb->b_io, older_than_this); |
Jens Axboe | 66f3b8e | 2009-09-02 09:19:46 +0200 | [diff] [blame] | 247 | } |
| 248 | |
Christoph Hellwig | a9185b4 | 2010-03-05 09:21:37 +0100 | [diff] [blame] | 249 | static int write_inode(struct inode *inode, struct writeback_control *wbc) |
Jens Axboe | 66f3b8e | 2009-09-02 09:19:46 +0200 | [diff] [blame] | 250 | { |
Jens Axboe | 03ba378 | 2009-09-09 09:08:54 +0200 | [diff] [blame] | 251 | if (inode->i_sb->s_op->write_inode && !is_bad_inode(inode)) |
Christoph Hellwig | a9185b4 | 2010-03-05 09:21:37 +0100 | [diff] [blame] | 252 | return inode->i_sb->s_op->write_inode(inode, wbc); |
Jens Axboe | 03ba378 | 2009-09-09 09:08:54 +0200 | [diff] [blame] | 253 | return 0; |
Fengguang Wu | 2c13657 | 2007-10-16 23:30:39 -0700 | [diff] [blame] | 254 | } |
| 255 | |
| 256 | /* |
Christoph Hellwig | 01c0319 | 2009-06-08 13:35:40 +0200 | [diff] [blame] | 257 | * Wait for writeback on an inode to complete. |
| 258 | */ |
| 259 | static void inode_wait_for_writeback(struct inode *inode) |
| 260 | { |
| 261 | DEFINE_WAIT_BIT(wq, &inode->i_state, __I_SYNC); |
| 262 | wait_queue_head_t *wqh; |
| 263 | |
| 264 | wqh = bit_waitqueue(&inode->i_state, __I_SYNC); |
Richard Kennedy | 58a9d3d | 2010-05-24 14:32:38 -0700 | [diff] [blame] | 265 | while (inode->i_state & I_SYNC) { |
Christoph Hellwig | 01c0319 | 2009-06-08 13:35:40 +0200 | [diff] [blame] | 266 | spin_unlock(&inode_lock); |
| 267 | __wait_on_bit(wqh, &wq, inode_wait, TASK_UNINTERRUPTIBLE); |
| 268 | spin_lock(&inode_lock); |
Richard Kennedy | 58a9d3d | 2010-05-24 14:32:38 -0700 | [diff] [blame] | 269 | } |
Christoph Hellwig | 01c0319 | 2009-06-08 13:35:40 +0200 | [diff] [blame] | 270 | } |
| 271 | |
| 272 | /* |
| 273 | * Write out an inode's dirty pages. Called under inode_lock. Either the |
| 274 | * caller has ref on the inode (either via __iget or via syscall against an fd) |
| 275 | * or the inode has I_WILL_FREE set (via generic_forget_inode) |
| 276 | * |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 277 | * If `wait' is set, wait on the writeout. |
| 278 | * |
| 279 | * The whole writeout design is quite complex and fragile. We want to avoid |
| 280 | * starvation of particular inodes when others are being redirtied, prevent |
| 281 | * livelocks, etc. |
| 282 | * |
| 283 | * Called under inode_lock. |
| 284 | */ |
| 285 | static int |
Christoph Hellwig | 01c0319 | 2009-06-08 13:35:40 +0200 | [diff] [blame] | 286 | writeback_single_inode(struct inode *inode, struct writeback_control *wbc) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 287 | { |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 288 | struct address_space *mapping = inode->i_mapping; |
Christoph Hellwig | 01c0319 | 2009-06-08 13:35:40 +0200 | [diff] [blame] | 289 | unsigned dirty; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 290 | int ret; |
| 291 | |
Christoph Hellwig | 01c0319 | 2009-06-08 13:35:40 +0200 | [diff] [blame] | 292 | if (!atomic_read(&inode->i_count)) |
| 293 | WARN_ON(!(inode->i_state & (I_WILL_FREE|I_FREEING))); |
| 294 | else |
| 295 | WARN_ON(inode->i_state & I_WILL_FREE); |
| 296 | |
| 297 | if (inode->i_state & I_SYNC) { |
| 298 | /* |
| 299 | * If this inode is locked for writeback and we are not doing |
Jens Axboe | 66f3b8e | 2009-09-02 09:19:46 +0200 | [diff] [blame] | 300 | * writeback-for-data-integrity, move it to b_more_io so that |
Christoph Hellwig | 01c0319 | 2009-06-08 13:35:40 +0200 | [diff] [blame] | 301 | * writeback can proceed with the other inodes on s_io. |
| 302 | * |
| 303 | * We'll have another go at writing back this inode when we |
Jens Axboe | 66f3b8e | 2009-09-02 09:19:46 +0200 | [diff] [blame] | 304 | * completed a full scan of b_io. |
Christoph Hellwig | 01c0319 | 2009-06-08 13:35:40 +0200 | [diff] [blame] | 305 | */ |
Christoph Hellwig | a9185b4 | 2010-03-05 09:21:37 +0100 | [diff] [blame] | 306 | if (wbc->sync_mode != WB_SYNC_ALL) { |
Christoph Hellwig | 01c0319 | 2009-06-08 13:35:40 +0200 | [diff] [blame] | 307 | requeue_io(inode); |
| 308 | return 0; |
| 309 | } |
| 310 | |
| 311 | /* |
| 312 | * It's a data-integrity sync. We must wait. |
| 313 | */ |
| 314 | inode_wait_for_writeback(inode); |
| 315 | } |
| 316 | |
Joern Engel | 1c0eeaf | 2007-10-16 23:30:44 -0700 | [diff] [blame] | 317 | BUG_ON(inode->i_state & I_SYNC); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 318 | |
Dmitry Monakhov | 5547e8a | 2010-05-07 13:35:44 +0400 | [diff] [blame] | 319 | /* Set I_SYNC, reset I_DIRTY_PAGES */ |
Joern Engel | 1c0eeaf | 2007-10-16 23:30:44 -0700 | [diff] [blame] | 320 | inode->i_state |= I_SYNC; |
Dmitry Monakhov | 5547e8a | 2010-05-07 13:35:44 +0400 | [diff] [blame] | 321 | inode->i_state &= ~I_DIRTY_PAGES; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 322 | spin_unlock(&inode_lock); |
| 323 | |
| 324 | ret = do_writepages(mapping, wbc); |
| 325 | |
Christoph Hellwig | 26821ed | 2010-03-05 09:21:21 +0100 | [diff] [blame] | 326 | /* |
| 327 | * Make sure to wait on the data before writing out the metadata. |
| 328 | * This is important for filesystems that modify metadata on data |
| 329 | * I/O completion. |
| 330 | */ |
Christoph Hellwig | a9185b4 | 2010-03-05 09:21:37 +0100 | [diff] [blame] | 331 | if (wbc->sync_mode == WB_SYNC_ALL) { |
Christoph Hellwig | 26821ed | 2010-03-05 09:21:21 +0100 | [diff] [blame] | 332 | int err = filemap_fdatawait(mapping); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 333 | if (ret == 0) |
| 334 | ret = err; |
| 335 | } |
| 336 | |
Dmitry Monakhov | 5547e8a | 2010-05-07 13:35:44 +0400 | [diff] [blame] | 337 | /* |
| 338 | * Some filesystems may redirty the inode during the writeback |
| 339 | * due to delalloc, clear dirty metadata flags right before |
| 340 | * write_inode() |
| 341 | */ |
| 342 | spin_lock(&inode_lock); |
| 343 | dirty = inode->i_state & I_DIRTY; |
| 344 | inode->i_state &= ~(I_DIRTY_SYNC | I_DIRTY_DATASYNC); |
| 345 | spin_unlock(&inode_lock); |
Christoph Hellwig | 26821ed | 2010-03-05 09:21:21 +0100 | [diff] [blame] | 346 | /* Don't write the inode if only I_DIRTY_PAGES was set */ |
| 347 | if (dirty & (I_DIRTY_SYNC | I_DIRTY_DATASYNC)) { |
Christoph Hellwig | a9185b4 | 2010-03-05 09:21:37 +0100 | [diff] [blame] | 348 | int err = write_inode(inode, wbc); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 349 | if (ret == 0) |
| 350 | ret = err; |
| 351 | } |
| 352 | |
| 353 | spin_lock(&inode_lock); |
Joern Engel | 1c0eeaf | 2007-10-16 23:30:44 -0700 | [diff] [blame] | 354 | inode->i_state &= ~I_SYNC; |
Al Viro | a4ffdde | 2010-06-02 17:38:30 -0400 | [diff] [blame] | 355 | if (!(inode->i_state & I_FREEING)) { |
Wu Fengguang | b3af946 | 2009-09-25 06:04:10 +0200 | [diff] [blame] | 356 | if ((inode->i_state & I_DIRTY_PAGES) && wbc->for_kupdate) { |
Wu Fengguang | ae1b7f7 | 2009-09-23 20:33:42 +0800 | [diff] [blame] | 357 | /* |
Wu Fengguang | b3af946 | 2009-09-25 06:04:10 +0200 | [diff] [blame] | 358 | * More pages get dirtied by a fast dirtier. |
| 359 | */ |
| 360 | goto select_queue; |
| 361 | } else if (inode->i_state & I_DIRTY) { |
| 362 | /* |
| 363 | * At least XFS will redirty the inode during the |
| 364 | * writeback (delalloc) and on io completion (isize). |
Wu Fengguang | ae1b7f7 | 2009-09-23 20:33:42 +0800 | [diff] [blame] | 365 | */ |
| 366 | redirty_tail(inode); |
| 367 | } else if (mapping_tagged(mapping, PAGECACHE_TAG_DIRTY)) { |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 368 | /* |
| 369 | * We didn't write back all the pages. nfs_writepages() |
| 370 | * sometimes bales out without doing anything. Redirty |
Jens Axboe | 66f3b8e | 2009-09-02 09:19:46 +0200 | [diff] [blame] | 371 | * the inode; Move it from b_io onto b_more_io/b_dirty. |
Andrew Morton | 1b43ef9 | 2007-10-16 23:30:35 -0700 | [diff] [blame] | 372 | */ |
| 373 | /* |
| 374 | * akpm: if the caller was the kupdate function we put |
Jens Axboe | 66f3b8e | 2009-09-02 09:19:46 +0200 | [diff] [blame] | 375 | * this inode at the head of b_dirty so it gets first |
Andrew Morton | 1b43ef9 | 2007-10-16 23:30:35 -0700 | [diff] [blame] | 376 | * consideration. Otherwise, move it to the tail, for |
| 377 | * the reasons described there. I'm not really sure |
| 378 | * how much sense this makes. Presumably I had a good |
| 379 | * reasons for doing it this way, and I'd rather not |
| 380 | * muck with it at present. |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 381 | */ |
| 382 | if (wbc->for_kupdate) { |
| 383 | /* |
Fengguang Wu | 2c13657 | 2007-10-16 23:30:39 -0700 | [diff] [blame] | 384 | * For the kupdate function we move the inode |
Jens Axboe | 66f3b8e | 2009-09-02 09:19:46 +0200 | [diff] [blame] | 385 | * to b_more_io so it will get more writeout as |
Fengguang Wu | 2c13657 | 2007-10-16 23:30:39 -0700 | [diff] [blame] | 386 | * soon as the queue becomes uncongested. |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 387 | */ |
| 388 | inode->i_state |= I_DIRTY_PAGES; |
Wu Fengguang | b3af946 | 2009-09-25 06:04:10 +0200 | [diff] [blame] | 389 | select_queue: |
Fengguang Wu | 8bc3be2 | 2008-02-04 22:29:36 -0800 | [diff] [blame] | 390 | if (wbc->nr_to_write <= 0) { |
| 391 | /* |
| 392 | * slice used up: queue for next turn |
| 393 | */ |
| 394 | requeue_io(inode); |
| 395 | } else { |
| 396 | /* |
| 397 | * somehow blocked: retry later |
| 398 | */ |
| 399 | redirty_tail(inode); |
| 400 | } |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 401 | } else { |
| 402 | /* |
| 403 | * Otherwise fully redirty the inode so that |
| 404 | * other inodes on this superblock will get some |
| 405 | * writeout. Otherwise heavy writing to one |
| 406 | * file would indefinitely suspend writeout of |
| 407 | * all the other files. |
| 408 | */ |
| 409 | inode->i_state |= I_DIRTY_PAGES; |
Andrew Morton | 1b43ef9 | 2007-10-16 23:30:35 -0700 | [diff] [blame] | 410 | redirty_tail(inode); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 411 | } |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 412 | } else if (atomic_read(&inode->i_count)) { |
| 413 | /* |
| 414 | * The inode is clean, inuse |
| 415 | */ |
| 416 | list_move(&inode->i_list, &inode_in_use); |
| 417 | } else { |
| 418 | /* |
| 419 | * The inode is clean, unused |
| 420 | */ |
| 421 | list_move(&inode->i_list, &inode_unused); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 422 | } |
| 423 | } |
Joern Engel | 1c0eeaf | 2007-10-16 23:30:44 -0700 | [diff] [blame] | 424 | inode_sync_complete(inode); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 425 | return ret; |
| 426 | } |
| 427 | |
Jens Axboe | 03ba378 | 2009-09-09 09:08:54 +0200 | [diff] [blame] | 428 | /* |
Christoph Hellwig | d19de7e | 2010-06-08 18:14:58 +0200 | [diff] [blame] | 429 | * For background writeback the caller does not have the sb pinned |
Jens Axboe | 03ba378 | 2009-09-09 09:08:54 +0200 | [diff] [blame] | 430 | * before calling writeback. So make sure that we do pin it, so it doesn't |
| 431 | * go away while we are writing inodes from it. |
Jens Axboe | 03ba378 | 2009-09-09 09:08:54 +0200 | [diff] [blame] | 432 | */ |
Christoph Hellwig | d19de7e | 2010-06-08 18:14:58 +0200 | [diff] [blame] | 433 | static bool pin_sb_for_writeback(struct super_block *sb) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 434 | { |
Jens Axboe | 03ba378 | 2009-09-09 09:08:54 +0200 | [diff] [blame] | 435 | spin_lock(&sb_lock); |
Christoph Hellwig | 29cb485 | 2010-06-09 15:31:01 +0200 | [diff] [blame] | 436 | if (list_empty(&sb->s_instances)) { |
| 437 | spin_unlock(&sb_lock); |
| 438 | return false; |
| 439 | } |
| 440 | |
Jens Axboe | 03ba378 | 2009-09-09 09:08:54 +0200 | [diff] [blame] | 441 | sb->s_count++; |
Christoph Hellwig | 29cb485 | 2010-06-09 15:31:01 +0200 | [diff] [blame] | 442 | spin_unlock(&sb_lock); |
| 443 | |
Jens Axboe | 03ba378 | 2009-09-09 09:08:54 +0200 | [diff] [blame] | 444 | if (down_read_trylock(&sb->s_umount)) { |
Christoph Hellwig | 29cb485 | 2010-06-09 15:31:01 +0200 | [diff] [blame] | 445 | if (sb->s_root) |
Christoph Hellwig | d19de7e | 2010-06-08 18:14:58 +0200 | [diff] [blame] | 446 | return true; |
Jens Axboe | 03ba378 | 2009-09-09 09:08:54 +0200 | [diff] [blame] | 447 | up_read(&sb->s_umount); |
| 448 | } |
Christoph Hellwig | 29cb485 | 2010-06-09 15:31:01 +0200 | [diff] [blame] | 449 | |
| 450 | put_super(sb); |
Christoph Hellwig | d19de7e | 2010-06-08 18:14:58 +0200 | [diff] [blame] | 451 | return false; |
Jens Axboe | 03ba378 | 2009-09-09 09:08:54 +0200 | [diff] [blame] | 452 | } |
| 453 | |
Edward Shishkin | f11c9c5 | 2010-03-11 14:09:47 -0800 | [diff] [blame] | 454 | /* |
| 455 | * Write a portion of b_io inodes which belong to @sb. |
Christoph Hellwig | edadfb1 | 2010-06-10 12:07:54 +0200 | [diff] [blame] | 456 | * |
| 457 | * If @only_this_sb is true, then find and write all such |
Edward Shishkin | f11c9c5 | 2010-03-11 14:09:47 -0800 | [diff] [blame] | 458 | * inodes. Otherwise write only ones which go sequentially |
| 459 | * in reverse order. |
Christoph Hellwig | edadfb1 | 2010-06-10 12:07:54 +0200 | [diff] [blame] | 460 | * |
Edward Shishkin | f11c9c5 | 2010-03-11 14:09:47 -0800 | [diff] [blame] | 461 | * Return 1, if the caller writeback routine should be |
| 462 | * interrupted. Otherwise return 0. |
| 463 | */ |
Christoph Hellwig | edadfb1 | 2010-06-10 12:07:54 +0200 | [diff] [blame] | 464 | static int writeback_sb_inodes(struct super_block *sb, struct bdi_writeback *wb, |
| 465 | struct writeback_control *wbc, bool only_this_sb) |
Jens Axboe | 03ba378 | 2009-09-09 09:08:54 +0200 | [diff] [blame] | 466 | { |
Jens Axboe | 03ba378 | 2009-09-09 09:08:54 +0200 | [diff] [blame] | 467 | while (!list_empty(&wb->b_io)) { |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 468 | long pages_skipped; |
Edward Shishkin | f11c9c5 | 2010-03-11 14:09:47 -0800 | [diff] [blame] | 469 | struct inode *inode = list_entry(wb->b_io.prev, |
| 470 | struct inode, i_list); |
Christoph Hellwig | edadfb1 | 2010-06-10 12:07:54 +0200 | [diff] [blame] | 471 | |
| 472 | if (inode->i_sb != sb) { |
| 473 | if (only_this_sb) { |
| 474 | /* |
| 475 | * We only want to write back data for this |
| 476 | * superblock, move all inodes not belonging |
| 477 | * to it back onto the dirty list. |
| 478 | */ |
| 479 | redirty_tail(inode); |
| 480 | continue; |
| 481 | } |
| 482 | |
| 483 | /* |
| 484 | * The inode belongs to a different superblock. |
| 485 | * Bounce back to the caller to unpin this and |
| 486 | * pin the next superblock. |
| 487 | */ |
Edward Shishkin | f11c9c5 | 2010-03-11 14:09:47 -0800 | [diff] [blame] | 488 | return 0; |
Christoph Hellwig | edadfb1 | 2010-06-10 12:07:54 +0200 | [diff] [blame] | 489 | } |
| 490 | |
Wu Fengguang | 84a8924 | 2009-06-16 15:33:17 -0700 | [diff] [blame] | 491 | if (inode->i_state & (I_NEW | I_WILL_FREE)) { |
Nick Piggin | 7ef0d73 | 2009-03-12 14:31:38 -0700 | [diff] [blame] | 492 | requeue_io(inode); |
| 493 | continue; |
| 494 | } |
Jeff Layton | d2caa3c | 2009-04-02 16:56:37 -0700 | [diff] [blame] | 495 | /* |
| 496 | * Was this inode dirtied after sync_sb_inodes was called? |
| 497 | * This keeps sync from extra jobs and livelock. |
| 498 | */ |
Edward Shishkin | f11c9c5 | 2010-03-11 14:09:47 -0800 | [diff] [blame] | 499 | if (inode_dirtied_after(inode, wbc->wb_start)) |
| 500 | return 1; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 501 | |
Al Viro | a4ffdde | 2010-06-02 17:38:30 -0400 | [diff] [blame] | 502 | BUG_ON(inode->i_state & I_FREEING); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 503 | __iget(inode); |
| 504 | pages_skipped = wbc->pages_skipped; |
Christoph Hellwig | 01c0319 | 2009-06-08 13:35:40 +0200 | [diff] [blame] | 505 | writeback_single_inode(inode, wbc); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 506 | if (wbc->pages_skipped != pages_skipped) { |
| 507 | /* |
| 508 | * writeback is not making progress due to locked |
| 509 | * buffers. Skip this inode for now. |
| 510 | */ |
Andrew Morton | f57b9b7 | 2007-10-16 23:30:34 -0700 | [diff] [blame] | 511 | redirty_tail(inode); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 512 | } |
| 513 | spin_unlock(&inode_lock); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 514 | iput(inode); |
OGAWA Hirofumi | 4ffc844 | 2006-03-25 03:07:44 -0800 | [diff] [blame] | 515 | cond_resched(); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 516 | spin_lock(&inode_lock); |
Fengguang Wu | 8bc3be2 | 2008-02-04 22:29:36 -0800 | [diff] [blame] | 517 | if (wbc->nr_to_write <= 0) { |
| 518 | wbc->more_io = 1; |
Edward Shishkin | f11c9c5 | 2010-03-11 14:09:47 -0800 | [diff] [blame] | 519 | return 1; |
Fengguang Wu | 8bc3be2 | 2008-02-04 22:29:36 -0800 | [diff] [blame] | 520 | } |
Jens Axboe | 03ba378 | 2009-09-09 09:08:54 +0200 | [diff] [blame] | 521 | if (!list_empty(&wb->b_more_io)) |
Fengguang Wu | 8bc3be2 | 2008-02-04 22:29:36 -0800 | [diff] [blame] | 522 | wbc->more_io = 1; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 523 | } |
Edward Shishkin | f11c9c5 | 2010-03-11 14:09:47 -0800 | [diff] [blame] | 524 | /* b_io is empty */ |
| 525 | return 1; |
| 526 | } |
Nick Piggin | 38f2197 | 2009-01-06 14:40:25 -0800 | [diff] [blame] | 527 | |
Christoph Hellwig | 9c3a8ee | 2010-06-10 12:07:27 +0200 | [diff] [blame] | 528 | void writeback_inodes_wb(struct bdi_writeback *wb, |
| 529 | struct writeback_control *wbc) |
Edward Shishkin | f11c9c5 | 2010-03-11 14:09:47 -0800 | [diff] [blame] | 530 | { |
| 531 | int ret = 0; |
Jens Axboe | 9ecc273 | 2009-09-24 15:25:11 +0200 | [diff] [blame] | 532 | |
Jan Kara | 7624ee7 | 2010-08-09 17:20:03 -0700 | [diff] [blame] | 533 | if (!wbc->wb_start) |
| 534 | wbc->wb_start = jiffies; /* livelock avoidance */ |
Edward Shishkin | f11c9c5 | 2010-03-11 14:09:47 -0800 | [diff] [blame] | 535 | spin_lock(&inode_lock); |
| 536 | if (!wbc->for_kupdate || list_empty(&wb->b_io)) |
| 537 | queue_io(wb, wbc->older_than_this); |
| 538 | |
| 539 | while (!list_empty(&wb->b_io)) { |
| 540 | struct inode *inode = list_entry(wb->b_io.prev, |
| 541 | struct inode, i_list); |
| 542 | struct super_block *sb = inode->i_sb; |
Edward Shishkin | f11c9c5 | 2010-03-11 14:09:47 -0800 | [diff] [blame] | 543 | |
Christoph Hellwig | edadfb1 | 2010-06-10 12:07:54 +0200 | [diff] [blame] | 544 | if (!pin_sb_for_writeback(sb)) { |
| 545 | requeue_io(inode); |
| 546 | continue; |
Edward Shishkin | f11c9c5 | 2010-03-11 14:09:47 -0800 | [diff] [blame] | 547 | } |
Christoph Hellwig | edadfb1 | 2010-06-10 12:07:54 +0200 | [diff] [blame] | 548 | ret = writeback_sb_inodes(sb, wb, wbc, false); |
| 549 | drop_super(sb); |
Edward Shishkin | f11c9c5 | 2010-03-11 14:09:47 -0800 | [diff] [blame] | 550 | |
Edward Shishkin | f11c9c5 | 2010-03-11 14:09:47 -0800 | [diff] [blame] | 551 | if (ret) |
| 552 | break; |
| 553 | } |
Jens Axboe | 66f3b8e | 2009-09-02 09:19:46 +0200 | [diff] [blame] | 554 | spin_unlock(&inode_lock); |
| 555 | /* Leave any unwritten inodes on b_io */ |
| 556 | } |
| 557 | |
Christoph Hellwig | edadfb1 | 2010-06-10 12:07:54 +0200 | [diff] [blame] | 558 | static void __writeback_inodes_sb(struct super_block *sb, |
| 559 | struct bdi_writeback *wb, struct writeback_control *wbc) |
| 560 | { |
| 561 | WARN_ON(!rwsem_is_locked(&sb->s_umount)); |
| 562 | |
Christoph Hellwig | edadfb1 | 2010-06-10 12:07:54 +0200 | [diff] [blame] | 563 | spin_lock(&inode_lock); |
| 564 | if (!wbc->for_kupdate || list_empty(&wb->b_io)) |
| 565 | queue_io(wb, wbc->older_than_this); |
| 566 | writeback_sb_inodes(sb, wb, wbc, true); |
| 567 | spin_unlock(&inode_lock); |
| 568 | } |
| 569 | |
Jens Axboe | 03ba378 | 2009-09-09 09:08:54 +0200 | [diff] [blame] | 570 | /* |
| 571 | * The maximum number of pages to writeout in a single bdi flush/kupdate |
| 572 | * operation. We do this so we don't hold I_SYNC against an inode for |
| 573 | * enormous amounts of time, which would block a userspace task which has |
| 574 | * been forced to throttle against that inode. Also, the code reevaluates |
| 575 | * the dirty each time it has written this many pages. |
| 576 | */ |
| 577 | #define MAX_WRITEBACK_PAGES 1024 |
| 578 | |
| 579 | static inline bool over_bground_thresh(void) |
| 580 | { |
| 581 | unsigned long background_thresh, dirty_thresh; |
| 582 | |
| 583 | get_dirty_limits(&background_thresh, &dirty_thresh, NULL, NULL); |
| 584 | |
| 585 | return (global_page_state(NR_FILE_DIRTY) + |
| 586 | global_page_state(NR_UNSTABLE_NFS) >= background_thresh); |
| 587 | } |
| 588 | |
| 589 | /* |
| 590 | * Explicit flushing or periodic writeback of "old" data. |
| 591 | * |
| 592 | * Define "old": the first time one of an inode's pages is dirtied, we mark the |
| 593 | * dirtying-time in the inode's address_space. So this periodic writeback code |
| 594 | * just walks the superblock inode list, writing back any inodes which are |
| 595 | * older than a specific point in time. |
| 596 | * |
| 597 | * Try to run once per dirty_writeback_interval. But if a writeback event |
| 598 | * takes longer than a dirty_writeback_interval interval, then leave a |
| 599 | * one-second gap. |
| 600 | * |
| 601 | * older_than_this takes precedence over nr_to_write. So we'll only write back |
| 602 | * all dirty pages if they are all attached to "old" mappings. |
| 603 | */ |
Jens Axboe | c4a77a6 | 2009-09-16 15:18:25 +0200 | [diff] [blame] | 604 | static long wb_writeback(struct bdi_writeback *wb, |
Christoph Hellwig | 83ba7b0 | 2010-07-06 08:59:53 +0200 | [diff] [blame] | 605 | struct wb_writeback_work *work) |
Jens Axboe | 03ba378 | 2009-09-09 09:08:54 +0200 | [diff] [blame] | 606 | { |
| 607 | struct writeback_control wbc = { |
Christoph Hellwig | 83ba7b0 | 2010-07-06 08:59:53 +0200 | [diff] [blame] | 608 | .sync_mode = work->sync_mode, |
Jens Axboe | 03ba378 | 2009-09-09 09:08:54 +0200 | [diff] [blame] | 609 | .older_than_this = NULL, |
Christoph Hellwig | 83ba7b0 | 2010-07-06 08:59:53 +0200 | [diff] [blame] | 610 | .for_kupdate = work->for_kupdate, |
| 611 | .for_background = work->for_background, |
| 612 | .range_cyclic = work->range_cyclic, |
Jens Axboe | 03ba378 | 2009-09-09 09:08:54 +0200 | [diff] [blame] | 613 | }; |
| 614 | unsigned long oldest_jif; |
| 615 | long wrote = 0; |
Jan Kara | a5989bd | 2009-09-16 19:22:48 +0200 | [diff] [blame] | 616 | struct inode *inode; |
Jens Axboe | 03ba378 | 2009-09-09 09:08:54 +0200 | [diff] [blame] | 617 | |
| 618 | if (wbc.for_kupdate) { |
| 619 | wbc.older_than_this = &oldest_jif; |
| 620 | oldest_jif = jiffies - |
| 621 | msecs_to_jiffies(dirty_expire_interval * 10); |
| 622 | } |
Jens Axboe | c4a77a6 | 2009-09-16 15:18:25 +0200 | [diff] [blame] | 623 | if (!wbc.range_cyclic) { |
| 624 | wbc.range_start = 0; |
| 625 | wbc.range_end = LLONG_MAX; |
| 626 | } |
Jens Axboe | 03ba378 | 2009-09-09 09:08:54 +0200 | [diff] [blame] | 627 | |
Jan Kara | 7624ee7 | 2010-08-09 17:20:03 -0700 | [diff] [blame] | 628 | wbc.wb_start = jiffies; /* livelock avoidance */ |
Jens Axboe | 03ba378 | 2009-09-09 09:08:54 +0200 | [diff] [blame] | 629 | for (;;) { |
| 630 | /* |
Wu Fengguang | d3ddec7 | 2009-09-23 20:33:40 +0800 | [diff] [blame] | 631 | * Stop writeback when nr_pages has been consumed |
Jens Axboe | 03ba378 | 2009-09-09 09:08:54 +0200 | [diff] [blame] | 632 | */ |
Christoph Hellwig | 83ba7b0 | 2010-07-06 08:59:53 +0200 | [diff] [blame] | 633 | if (work->nr_pages <= 0) |
Jens Axboe | 03ba378 | 2009-09-09 09:08:54 +0200 | [diff] [blame] | 634 | break; |
| 635 | |
| 636 | /* |
Wu Fengguang | d3ddec7 | 2009-09-23 20:33:40 +0800 | [diff] [blame] | 637 | * For background writeout, stop when we are below the |
| 638 | * background dirty threshold |
Jens Axboe | 03ba378 | 2009-09-09 09:08:54 +0200 | [diff] [blame] | 639 | */ |
Christoph Hellwig | 83ba7b0 | 2010-07-06 08:59:53 +0200 | [diff] [blame] | 640 | if (work->for_background && !over_bground_thresh()) |
Jens Axboe | 03ba378 | 2009-09-09 09:08:54 +0200 | [diff] [blame] | 641 | break; |
| 642 | |
| 643 | wbc.more_io = 0; |
Jens Axboe | 03ba378 | 2009-09-09 09:08:54 +0200 | [diff] [blame] | 644 | wbc.nr_to_write = MAX_WRITEBACK_PAGES; |
| 645 | wbc.pages_skipped = 0; |
Christoph Hellwig | 83ba7b0 | 2010-07-06 08:59:53 +0200 | [diff] [blame] | 646 | if (work->sb) |
| 647 | __writeback_inodes_sb(work->sb, wb, &wbc); |
Christoph Hellwig | edadfb1 | 2010-06-10 12:07:54 +0200 | [diff] [blame] | 648 | else |
| 649 | writeback_inodes_wb(wb, &wbc); |
Christoph Hellwig | 83ba7b0 | 2010-07-06 08:59:53 +0200 | [diff] [blame] | 650 | work->nr_pages -= MAX_WRITEBACK_PAGES - wbc.nr_to_write; |
Jens Axboe | 03ba378 | 2009-09-09 09:08:54 +0200 | [diff] [blame] | 651 | wrote += MAX_WRITEBACK_PAGES - wbc.nr_to_write; |
| 652 | |
| 653 | /* |
Jens Axboe | 71fd05a | 2009-09-23 19:32:26 +0200 | [diff] [blame] | 654 | * If we consumed everything, see if we have more |
Jens Axboe | 03ba378 | 2009-09-09 09:08:54 +0200 | [diff] [blame] | 655 | */ |
Jens Axboe | 71fd05a | 2009-09-23 19:32:26 +0200 | [diff] [blame] | 656 | if (wbc.nr_to_write <= 0) |
| 657 | continue; |
| 658 | /* |
| 659 | * Didn't write everything and we don't have more IO, bail |
| 660 | */ |
| 661 | if (!wbc.more_io) |
Jens Axboe | 03ba378 | 2009-09-09 09:08:54 +0200 | [diff] [blame] | 662 | break; |
Jens Axboe | 71fd05a | 2009-09-23 19:32:26 +0200 | [diff] [blame] | 663 | /* |
| 664 | * Did we write something? Try for more |
| 665 | */ |
| 666 | if (wbc.nr_to_write < MAX_WRITEBACK_PAGES) |
| 667 | continue; |
| 668 | /* |
| 669 | * Nothing written. Wait for some inode to |
| 670 | * become available for writeback. Otherwise |
| 671 | * we'll just busyloop. |
| 672 | */ |
| 673 | spin_lock(&inode_lock); |
| 674 | if (!list_empty(&wb->b_more_io)) { |
| 675 | inode = list_entry(wb->b_more_io.prev, |
| 676 | struct inode, i_list); |
| 677 | inode_wait_for_writeback(inode); |
Jens Axboe | 03ba378 | 2009-09-09 09:08:54 +0200 | [diff] [blame] | 678 | } |
Jens Axboe | 71fd05a | 2009-09-23 19:32:26 +0200 | [diff] [blame] | 679 | spin_unlock(&inode_lock); |
Jens Axboe | 03ba378 | 2009-09-09 09:08:54 +0200 | [diff] [blame] | 680 | } |
| 681 | |
| 682 | return wrote; |
| 683 | } |
| 684 | |
| 685 | /* |
Christoph Hellwig | 83ba7b0 | 2010-07-06 08:59:53 +0200 | [diff] [blame] | 686 | * 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] | 687 | */ |
Christoph Hellwig | 83ba7b0 | 2010-07-06 08:59:53 +0200 | [diff] [blame] | 688 | static struct wb_writeback_work * |
| 689 | get_next_work_item(struct backing_dev_info *bdi, struct bdi_writeback *wb) |
Jens Axboe | 03ba378 | 2009-09-09 09:08:54 +0200 | [diff] [blame] | 690 | { |
Christoph Hellwig | 83ba7b0 | 2010-07-06 08:59:53 +0200 | [diff] [blame] | 691 | struct wb_writeback_work *work = NULL; |
Jens Axboe | 03ba378 | 2009-09-09 09:08:54 +0200 | [diff] [blame] | 692 | |
Christoph Hellwig | 83ba7b0 | 2010-07-06 08:59:53 +0200 | [diff] [blame] | 693 | spin_lock(&bdi->wb_lock); |
| 694 | if (!list_empty(&bdi->work_list)) { |
| 695 | work = list_entry(bdi->work_list.next, |
| 696 | struct wb_writeback_work, list); |
| 697 | list_del_init(&work->list); |
Jens Axboe | 03ba378 | 2009-09-09 09:08:54 +0200 | [diff] [blame] | 698 | } |
Christoph Hellwig | 83ba7b0 | 2010-07-06 08:59:53 +0200 | [diff] [blame] | 699 | spin_unlock(&bdi->wb_lock); |
| 700 | return work; |
Jens Axboe | 03ba378 | 2009-09-09 09:08:54 +0200 | [diff] [blame] | 701 | } |
| 702 | |
| 703 | static long wb_check_old_data_flush(struct bdi_writeback *wb) |
| 704 | { |
| 705 | unsigned long expired; |
| 706 | long nr_pages; |
| 707 | |
Jens Axboe | 69b62d0 | 2010-05-17 12:51:03 +0200 | [diff] [blame] | 708 | /* |
| 709 | * When set to zero, disable periodic writeback |
| 710 | */ |
| 711 | if (!dirty_writeback_interval) |
| 712 | return 0; |
| 713 | |
Jens Axboe | 03ba378 | 2009-09-09 09:08:54 +0200 | [diff] [blame] | 714 | expired = wb->last_old_flush + |
| 715 | msecs_to_jiffies(dirty_writeback_interval * 10); |
| 716 | if (time_before(jiffies, expired)) |
| 717 | return 0; |
| 718 | |
| 719 | wb->last_old_flush = jiffies; |
| 720 | nr_pages = global_page_state(NR_FILE_DIRTY) + |
| 721 | global_page_state(NR_UNSTABLE_NFS) + |
| 722 | (inodes_stat.nr_inodes - inodes_stat.nr_unused); |
| 723 | |
Jens Axboe | c4a77a6 | 2009-09-16 15:18:25 +0200 | [diff] [blame] | 724 | if (nr_pages) { |
Christoph Hellwig | 83ba7b0 | 2010-07-06 08:59:53 +0200 | [diff] [blame] | 725 | struct wb_writeback_work work = { |
Jens Axboe | c4a77a6 | 2009-09-16 15:18:25 +0200 | [diff] [blame] | 726 | .nr_pages = nr_pages, |
| 727 | .sync_mode = WB_SYNC_NONE, |
| 728 | .for_kupdate = 1, |
| 729 | .range_cyclic = 1, |
| 730 | }; |
| 731 | |
Christoph Hellwig | 83ba7b0 | 2010-07-06 08:59:53 +0200 | [diff] [blame] | 732 | return wb_writeback(wb, &work); |
Jens Axboe | c4a77a6 | 2009-09-16 15:18:25 +0200 | [diff] [blame] | 733 | } |
Jens Axboe | 03ba378 | 2009-09-09 09:08:54 +0200 | [diff] [blame] | 734 | |
| 735 | return 0; |
| 736 | } |
| 737 | |
| 738 | /* |
| 739 | * Retrieve work items and do the writeback they describe |
| 740 | */ |
| 741 | long wb_do_writeback(struct bdi_writeback *wb, int force_wait) |
| 742 | { |
| 743 | struct backing_dev_info *bdi = wb->bdi; |
Christoph Hellwig | 83ba7b0 | 2010-07-06 08:59:53 +0200 | [diff] [blame] | 744 | struct wb_writeback_work *work; |
Jens Axboe | c4a77a6 | 2009-09-16 15:18:25 +0200 | [diff] [blame] | 745 | long wrote = 0; |
Jens Axboe | 03ba378 | 2009-09-09 09:08:54 +0200 | [diff] [blame] | 746 | |
| 747 | while ((work = get_next_work_item(bdi, wb)) != NULL) { |
Jens Axboe | 03ba378 | 2009-09-09 09:08:54 +0200 | [diff] [blame] | 748 | /* |
| 749 | * Override sync mode, in case we must wait for completion |
Christoph Hellwig | 83ba7b0 | 2010-07-06 08:59:53 +0200 | [diff] [blame] | 750 | * because this thread is exiting now. |
Jens Axboe | 03ba378 | 2009-09-09 09:08:54 +0200 | [diff] [blame] | 751 | */ |
| 752 | if (force_wait) |
Christoph Hellwig | 83ba7b0 | 2010-07-06 08:59:53 +0200 | [diff] [blame] | 753 | work->sync_mode = WB_SYNC_ALL; |
| 754 | |
| 755 | wrote += wb_writeback(wb, work); |
Jens Axboe | 03ba378 | 2009-09-09 09:08:54 +0200 | [diff] [blame] | 756 | |
| 757 | /* |
Christoph Hellwig | 83ba7b0 | 2010-07-06 08:59:53 +0200 | [diff] [blame] | 758 | * Notify the caller of completion if this is a synchronous |
| 759 | * work item, otherwise just free it. |
Jens Axboe | 03ba378 | 2009-09-09 09:08:54 +0200 | [diff] [blame] | 760 | */ |
Christoph Hellwig | 83ba7b0 | 2010-07-06 08:59:53 +0200 | [diff] [blame] | 761 | if (work->done) |
| 762 | complete(work->done); |
| 763 | else |
| 764 | kfree(work); |
Jens Axboe | 03ba378 | 2009-09-09 09:08:54 +0200 | [diff] [blame] | 765 | } |
| 766 | |
| 767 | /* |
| 768 | * Check for periodic writeback, kupdated() style |
| 769 | */ |
| 770 | wrote += wb_check_old_data_flush(wb); |
| 771 | |
| 772 | return wrote; |
| 773 | } |
| 774 | |
| 775 | /* |
| 776 | * Handle writeback of dirty data for the device backed by this bdi. Also |
| 777 | * wakes up periodically and does kupdated style flushing. |
| 778 | */ |
| 779 | int bdi_writeback_task(struct bdi_writeback *wb) |
| 780 | { |
| 781 | unsigned long last_active = jiffies; |
| 782 | unsigned long wait_jiffies = -1UL; |
| 783 | long pages_written; |
| 784 | |
| 785 | while (!kthread_should_stop()) { |
| 786 | pages_written = wb_do_writeback(wb, 0); |
| 787 | |
| 788 | if (pages_written) |
| 789 | last_active = jiffies; |
| 790 | else if (wait_jiffies != -1UL) { |
| 791 | unsigned long max_idle; |
| 792 | |
| 793 | /* |
| 794 | * Longest period of inactivity that we tolerate. If we |
| 795 | * see dirty data again later, the task will get |
| 796 | * recreated automatically. |
| 797 | */ |
| 798 | max_idle = max(5UL * 60 * HZ, wait_jiffies); |
| 799 | if (time_after(jiffies, max_idle + last_active)) |
| 800 | break; |
| 801 | } |
| 802 | |
Jens Axboe | 69b62d0 | 2010-05-17 12:51:03 +0200 | [diff] [blame] | 803 | if (dirty_writeback_interval) { |
| 804 | wait_jiffies = msecs_to_jiffies(dirty_writeback_interval * 10); |
| 805 | schedule_timeout_interruptible(wait_jiffies); |
Jens Axboe | f9eadbb | 2010-05-18 14:31:45 +0200 | [diff] [blame] | 806 | } else { |
| 807 | set_current_state(TASK_INTERRUPTIBLE); |
| 808 | if (list_empty_careful(&wb->bdi->work_list) && |
| 809 | !kthread_should_stop()) |
| 810 | schedule(); |
| 811 | __set_current_state(TASK_RUNNING); |
| 812 | } |
Jens Axboe | 69b62d0 | 2010-05-17 12:51:03 +0200 | [diff] [blame] | 813 | |
Jens Axboe | 03ba378 | 2009-09-09 09:08:54 +0200 | [diff] [blame] | 814 | try_to_freeze(); |
| 815 | } |
| 816 | |
| 817 | return 0; |
| 818 | } |
| 819 | |
| 820 | /* |
Jens Axboe | 03ba378 | 2009-09-09 09:08:54 +0200 | [diff] [blame] | 821 | * Start writeback of `nr_pages' pages. If `nr_pages' is zero, write back |
| 822 | * the whole world. |
| 823 | */ |
| 824 | void wakeup_flusher_threads(long nr_pages) |
| 825 | { |
Christoph Hellwig | b8c2f34 | 2010-06-08 18:15:07 +0200 | [diff] [blame] | 826 | struct backing_dev_info *bdi; |
Christoph Hellwig | b8c2f34 | 2010-06-08 18:15:07 +0200 | [diff] [blame] | 827 | |
Christoph Hellwig | 83ba7b0 | 2010-07-06 08:59:53 +0200 | [diff] [blame] | 828 | if (!nr_pages) { |
| 829 | nr_pages = global_page_state(NR_FILE_DIRTY) + |
Jens Axboe | 03ba378 | 2009-09-09 09:08:54 +0200 | [diff] [blame] | 830 | global_page_state(NR_UNSTABLE_NFS); |
Christoph Hellwig | b8c2f34 | 2010-06-08 18:15:07 +0200 | [diff] [blame] | 831 | } |
| 832 | |
| 833 | rcu_read_lock(); |
| 834 | list_for_each_entry_rcu(bdi, &bdi_list, bdi_list) { |
| 835 | if (!bdi_has_dirty_io(bdi)) |
| 836 | continue; |
Christoph Hellwig | 83ba7b0 | 2010-07-06 08:59:53 +0200 | [diff] [blame] | 837 | __bdi_start_writeback(bdi, nr_pages, false, false); |
Christoph Hellwig | b8c2f34 | 2010-06-08 18:15:07 +0200 | [diff] [blame] | 838 | } |
| 839 | rcu_read_unlock(); |
Jens Axboe | 03ba378 | 2009-09-09 09:08:54 +0200 | [diff] [blame] | 840 | } |
| 841 | |
| 842 | static noinline void block_dump___mark_inode_dirty(struct inode *inode) |
| 843 | { |
| 844 | if (inode->i_ino || strcmp(inode->i_sb->s_id, "bdev")) { |
| 845 | struct dentry *dentry; |
| 846 | const char *name = "?"; |
| 847 | |
| 848 | dentry = d_find_alias(inode); |
| 849 | if (dentry) { |
| 850 | spin_lock(&dentry->d_lock); |
| 851 | name = (const char *) dentry->d_name.name; |
| 852 | } |
| 853 | printk(KERN_DEBUG |
| 854 | "%s(%d): dirtied inode %lu (%s) on %s\n", |
| 855 | current->comm, task_pid_nr(current), inode->i_ino, |
| 856 | name, inode->i_sb->s_id); |
| 857 | if (dentry) { |
| 858 | spin_unlock(&dentry->d_lock); |
| 859 | dput(dentry); |
| 860 | } |
| 861 | } |
| 862 | } |
| 863 | |
| 864 | /** |
| 865 | * __mark_inode_dirty - internal function |
| 866 | * @inode: inode to mark |
| 867 | * @flags: what kind of dirty (i.e. I_DIRTY_SYNC) |
| 868 | * Mark an inode as dirty. Callers should use mark_inode_dirty or |
| 869 | * mark_inode_dirty_sync. |
| 870 | * |
| 871 | * Put the inode on the super block's dirty list. |
| 872 | * |
| 873 | * CAREFUL! We mark it dirty unconditionally, but move it onto the |
| 874 | * dirty list only if it is hashed or if it refers to a blockdev. |
| 875 | * If it was not hashed, it will never be added to the dirty list |
| 876 | * even if it is later hashed, as it will have been marked dirty already. |
| 877 | * |
| 878 | * In short, make sure you hash any inodes _before_ you start marking |
| 879 | * them dirty. |
| 880 | * |
| 881 | * This function *must* be atomic for the I_DIRTY_PAGES case - |
| 882 | * set_page_dirty() is called under spinlock in several places. |
| 883 | * |
| 884 | * Note that for blockdevs, inode->dirtied_when represents the dirtying time of |
| 885 | * the block-special inode (/dev/hda1) itself. And the ->dirtied_when field of |
| 886 | * the kernel-internal blockdev inode represents the dirtying time of the |
| 887 | * blockdev's pages. This is why for I_DIRTY_PAGES we always use |
| 888 | * page->mapping->host, so the page-dirtying time is recorded in the internal |
| 889 | * blockdev inode. |
| 890 | */ |
| 891 | void __mark_inode_dirty(struct inode *inode, int flags) |
| 892 | { |
| 893 | struct super_block *sb = inode->i_sb; |
| 894 | |
| 895 | /* |
| 896 | * Don't do this for I_DIRTY_PAGES - that doesn't actually |
| 897 | * dirty the inode itself |
| 898 | */ |
| 899 | if (flags & (I_DIRTY_SYNC | I_DIRTY_DATASYNC)) { |
| 900 | if (sb->s_op->dirty_inode) |
| 901 | sb->s_op->dirty_inode(inode); |
| 902 | } |
| 903 | |
| 904 | /* |
| 905 | * make sure that changes are seen by all cpus before we test i_state |
| 906 | * -- mikulas |
| 907 | */ |
| 908 | smp_mb(); |
| 909 | |
| 910 | /* avoid the locking if we can */ |
| 911 | if ((inode->i_state & flags) == flags) |
| 912 | return; |
| 913 | |
| 914 | if (unlikely(block_dump)) |
| 915 | block_dump___mark_inode_dirty(inode); |
| 916 | |
| 917 | spin_lock(&inode_lock); |
| 918 | if ((inode->i_state & flags) != flags) { |
| 919 | const int was_dirty = inode->i_state & I_DIRTY; |
| 920 | |
| 921 | inode->i_state |= flags; |
| 922 | |
| 923 | /* |
| 924 | * If the inode is being synced, just update its dirty state. |
| 925 | * The unlocker will place the inode on the appropriate |
| 926 | * superblock list, based upon its state. |
| 927 | */ |
| 928 | if (inode->i_state & I_SYNC) |
| 929 | goto out; |
| 930 | |
| 931 | /* |
| 932 | * Only add valid (hashed) inodes to the superblock's |
| 933 | * dirty list. Add blockdev inodes as well. |
| 934 | */ |
| 935 | if (!S_ISBLK(inode->i_mode)) { |
| 936 | if (hlist_unhashed(&inode->i_hash)) |
| 937 | goto out; |
| 938 | } |
Al Viro | a4ffdde | 2010-06-02 17:38:30 -0400 | [diff] [blame] | 939 | if (inode->i_state & I_FREEING) |
Jens Axboe | 03ba378 | 2009-09-09 09:08:54 +0200 | [diff] [blame] | 940 | goto out; |
| 941 | |
| 942 | /* |
| 943 | * If the inode was already on b_dirty/b_io/b_more_io, don't |
| 944 | * reposition it (that would break b_dirty time-ordering). |
| 945 | */ |
| 946 | if (!was_dirty) { |
| 947 | struct bdi_writeback *wb = &inode_to_bdi(inode)->wb; |
Jens Axboe | 500b067 | 2009-09-09 09:10:25 +0200 | [diff] [blame] | 948 | struct backing_dev_info *bdi = wb->bdi; |
| 949 | |
| 950 | if (bdi_cap_writeback_dirty(bdi) && |
| 951 | !test_bit(BDI_registered, &bdi->state)) { |
| 952 | WARN_ON(1); |
| 953 | printk(KERN_ERR "bdi-%s not registered\n", |
| 954 | bdi->name); |
| 955 | } |
Jens Axboe | 03ba378 | 2009-09-09 09:08:54 +0200 | [diff] [blame] | 956 | |
| 957 | inode->dirtied_when = jiffies; |
| 958 | list_move(&inode->i_list, &wb->b_dirty); |
| 959 | } |
| 960 | } |
| 961 | out: |
| 962 | spin_unlock(&inode_lock); |
| 963 | } |
| 964 | EXPORT_SYMBOL(__mark_inode_dirty); |
| 965 | |
Jens Axboe | 66f3b8e | 2009-09-02 09:19:46 +0200 | [diff] [blame] | 966 | /* |
| 967 | * Write out a superblock's list of dirty inodes. A wait will be performed |
| 968 | * upon no inodes, all inodes or the final one, depending upon sync_mode. |
| 969 | * |
| 970 | * If older_than_this is non-NULL, then only write out inodes which |
| 971 | * had their first dirtying at a time earlier than *older_than_this. |
| 972 | * |
Jens Axboe | 66f3b8e | 2009-09-02 09:19:46 +0200 | [diff] [blame] | 973 | * If `bdi' is non-zero then we're being asked to writeback a specific queue. |
| 974 | * This function assumes that the blockdev superblock's inodes are backed by |
| 975 | * a variety of queues, so all inodes are searched. For other superblocks, |
| 976 | * assume that all inodes are backed by the same queue. |
| 977 | * |
Jens Axboe | 66f3b8e | 2009-09-02 09:19:46 +0200 | [diff] [blame] | 978 | * The inodes to be written are parked on bdi->b_io. They are moved back onto |
| 979 | * bdi->b_dirty as they are selected for writing. This way, none can be missed |
| 980 | * on the writer throttling path, and we get decent balancing between many |
| 981 | * throttled threads: we don't want them all piling up on inode_sync_wait. |
| 982 | */ |
Jens Axboe | b6e5131 | 2009-09-16 15:13:54 +0200 | [diff] [blame] | 983 | static void wait_sb_inodes(struct super_block *sb) |
Jens Axboe | 66f3b8e | 2009-09-02 09:19:46 +0200 | [diff] [blame] | 984 | { |
Jens Axboe | 03ba378 | 2009-09-09 09:08:54 +0200 | [diff] [blame] | 985 | struct inode *inode, *old_inode = NULL; |
Jens Axboe | 66f3b8e | 2009-09-02 09:19:46 +0200 | [diff] [blame] | 986 | |
Jens Axboe | 03ba378 | 2009-09-09 09:08:54 +0200 | [diff] [blame] | 987 | /* |
| 988 | * We need to be protected against the filesystem going from |
| 989 | * r/o to r/w or vice versa. |
| 990 | */ |
Jens Axboe | b6e5131 | 2009-09-16 15:13:54 +0200 | [diff] [blame] | 991 | WARN_ON(!rwsem_is_locked(&sb->s_umount)); |
Jens Axboe | 66f3b8e | 2009-09-02 09:19:46 +0200 | [diff] [blame] | 992 | |
Jens Axboe | 03ba378 | 2009-09-09 09:08:54 +0200 | [diff] [blame] | 993 | spin_lock(&inode_lock); |
| 994 | |
| 995 | /* |
| 996 | * Data integrity sync. Must wait for all pages under writeback, |
| 997 | * because there may have been pages dirtied before our sync |
| 998 | * call, but which had writeout started before we write it out. |
| 999 | * In which case, the inode may not be on the dirty list, but |
| 1000 | * we still have to wait for that writeout. |
| 1001 | */ |
Jens Axboe | b6e5131 | 2009-09-16 15:13:54 +0200 | [diff] [blame] | 1002 | list_for_each_entry(inode, &sb->s_inodes, i_sb_list) { |
Jens Axboe | 03ba378 | 2009-09-09 09:08:54 +0200 | [diff] [blame] | 1003 | struct address_space *mapping; |
| 1004 | |
Al Viro | a4ffdde | 2010-06-02 17:38:30 -0400 | [diff] [blame] | 1005 | if (inode->i_state & (I_FREEING|I_WILL_FREE|I_NEW)) |
Jens Axboe | 03ba378 | 2009-09-09 09:08:54 +0200 | [diff] [blame] | 1006 | continue; |
| 1007 | mapping = inode->i_mapping; |
| 1008 | if (mapping->nrpages == 0) |
| 1009 | continue; |
| 1010 | __iget(inode); |
| 1011 | spin_unlock(&inode_lock); |
| 1012 | /* |
| 1013 | * We hold a reference to 'inode' so it couldn't have |
| 1014 | * been removed from s_inodes list while we dropped the |
| 1015 | * inode_lock. We cannot iput the inode now as we can |
| 1016 | * be holding the last reference and we cannot iput it |
| 1017 | * under inode_lock. So we keep the reference and iput |
| 1018 | * it later. |
| 1019 | */ |
| 1020 | iput(old_inode); |
| 1021 | old_inode = inode; |
| 1022 | |
| 1023 | filemap_fdatawait(mapping); |
| 1024 | |
| 1025 | cond_resched(); |
Nick Piggin | 38f2197 | 2009-01-06 14:40:25 -0800 | [diff] [blame] | 1026 | |
Jens Axboe | 66f3b8e | 2009-09-02 09:19:46 +0200 | [diff] [blame] | 1027 | spin_lock(&inode_lock); |
Jens Axboe | 66f3b8e | 2009-09-02 09:19:46 +0200 | [diff] [blame] | 1028 | } |
Jens Axboe | 03ba378 | 2009-09-09 09:08:54 +0200 | [diff] [blame] | 1029 | spin_unlock(&inode_lock); |
| 1030 | iput(old_inode); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1031 | } |
| 1032 | |
Jens Axboe | d8a8559 | 2009-09-02 12:34:32 +0200 | [diff] [blame] | 1033 | /** |
| 1034 | * writeback_inodes_sb - writeback dirty inodes from given super_block |
| 1035 | * @sb: the superblock |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1036 | * |
Jens Axboe | d8a8559 | 2009-09-02 12:34:32 +0200 | [diff] [blame] | 1037 | * Start writeback on some inodes on this super_block. No guarantees are made |
| 1038 | * on how many (if any) will be written, and this function does not wait |
| 1039 | * for IO completion of submitted IO. The number of pages submitted is |
| 1040 | * returned. |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1041 | */ |
Jens Axboe | b6e5131 | 2009-09-16 15:13:54 +0200 | [diff] [blame] | 1042 | void writeback_inodes_sb(struct super_block *sb) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1043 | { |
Jens Axboe | 0e3c9a2 | 2010-06-01 11:08:43 +0200 | [diff] [blame] | 1044 | unsigned long nr_dirty = global_page_state(NR_FILE_DIRTY); |
| 1045 | unsigned long nr_unstable = global_page_state(NR_UNSTABLE_NFS); |
Christoph Hellwig | 83ba7b0 | 2010-07-06 08:59:53 +0200 | [diff] [blame] | 1046 | DECLARE_COMPLETION_ONSTACK(done); |
| 1047 | struct wb_writeback_work work = { |
Christoph Hellwig | 3c4d716 | 2010-06-08 18:14:43 +0200 | [diff] [blame] | 1048 | .sb = sb, |
| 1049 | .sync_mode = WB_SYNC_NONE, |
Christoph Hellwig | 83ba7b0 | 2010-07-06 08:59:53 +0200 | [diff] [blame] | 1050 | .done = &done, |
Christoph Hellwig | 3c4d716 | 2010-06-08 18:14:43 +0200 | [diff] [blame] | 1051 | }; |
Jens Axboe | 0e3c9a2 | 2010-06-01 11:08:43 +0200 | [diff] [blame] | 1052 | |
Christoph Hellwig | cf37e97 | 2010-06-08 18:14:51 +0200 | [diff] [blame] | 1053 | WARN_ON(!rwsem_is_locked(&sb->s_umount)); |
| 1054 | |
Christoph Hellwig | 83ba7b0 | 2010-07-06 08:59:53 +0200 | [diff] [blame] | 1055 | work.nr_pages = nr_dirty + nr_unstable + |
Jens Axboe | 0e3c9a2 | 2010-06-01 11:08:43 +0200 | [diff] [blame] | 1056 | (inodes_stat.nr_inodes - inodes_stat.nr_unused); |
| 1057 | |
Christoph Hellwig | 83ba7b0 | 2010-07-06 08:59:53 +0200 | [diff] [blame] | 1058 | bdi_queue_work(sb->s_bdi, &work); |
| 1059 | wait_for_completion(&done); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1060 | } |
Jens Axboe | d8a8559 | 2009-09-02 12:34:32 +0200 | [diff] [blame] | 1061 | EXPORT_SYMBOL(writeback_inodes_sb); |
| 1062 | |
| 1063 | /** |
Eric Sandeen | 17bd55d | 2009-12-23 07:57:07 -0500 | [diff] [blame] | 1064 | * writeback_inodes_sb_if_idle - start writeback if none underway |
| 1065 | * @sb: the superblock |
| 1066 | * |
| 1067 | * Invoke writeback_inodes_sb if no writeback is currently underway. |
| 1068 | * Returns 1 if writeback was started, 0 if not. |
| 1069 | */ |
| 1070 | int writeback_inodes_sb_if_idle(struct super_block *sb) |
| 1071 | { |
| 1072 | if (!writeback_in_progress(sb->s_bdi)) { |
Christoph Hellwig | cf37e97 | 2010-06-08 18:14:51 +0200 | [diff] [blame] | 1073 | down_read(&sb->s_umount); |
Eric Sandeen | 17bd55d | 2009-12-23 07:57:07 -0500 | [diff] [blame] | 1074 | writeback_inodes_sb(sb); |
Christoph Hellwig | cf37e97 | 2010-06-08 18:14:51 +0200 | [diff] [blame] | 1075 | up_read(&sb->s_umount); |
Eric Sandeen | 17bd55d | 2009-12-23 07:57:07 -0500 | [diff] [blame] | 1076 | return 1; |
| 1077 | } else |
| 1078 | return 0; |
| 1079 | } |
| 1080 | EXPORT_SYMBOL(writeback_inodes_sb_if_idle); |
| 1081 | |
| 1082 | /** |
Jens Axboe | d8a8559 | 2009-09-02 12:34:32 +0200 | [diff] [blame] | 1083 | * sync_inodes_sb - sync sb inode pages |
| 1084 | * @sb: the superblock |
| 1085 | * |
| 1086 | * This function writes and waits on any dirty inode belonging to this |
| 1087 | * super_block. The number of pages synced is returned. |
| 1088 | */ |
Jens Axboe | b6e5131 | 2009-09-16 15:13:54 +0200 | [diff] [blame] | 1089 | void sync_inodes_sb(struct super_block *sb) |
Jens Axboe | d8a8559 | 2009-09-02 12:34:32 +0200 | [diff] [blame] | 1090 | { |
Christoph Hellwig | 83ba7b0 | 2010-07-06 08:59:53 +0200 | [diff] [blame] | 1091 | DECLARE_COMPLETION_ONSTACK(done); |
| 1092 | struct wb_writeback_work work = { |
Christoph Hellwig | 3c4d716 | 2010-06-08 18:14:43 +0200 | [diff] [blame] | 1093 | .sb = sb, |
| 1094 | .sync_mode = WB_SYNC_ALL, |
| 1095 | .nr_pages = LONG_MAX, |
| 1096 | .range_cyclic = 0, |
Christoph Hellwig | 83ba7b0 | 2010-07-06 08:59:53 +0200 | [diff] [blame] | 1097 | .done = &done, |
Christoph Hellwig | 3c4d716 | 2010-06-08 18:14:43 +0200 | [diff] [blame] | 1098 | }; |
| 1099 | |
Christoph Hellwig | cf37e97 | 2010-06-08 18:14:51 +0200 | [diff] [blame] | 1100 | WARN_ON(!rwsem_is_locked(&sb->s_umount)); |
| 1101 | |
Christoph Hellwig | 83ba7b0 | 2010-07-06 08:59:53 +0200 | [diff] [blame] | 1102 | bdi_queue_work(sb->s_bdi, &work); |
| 1103 | wait_for_completion(&done); |
| 1104 | |
Jens Axboe | b6e5131 | 2009-09-16 15:13:54 +0200 | [diff] [blame] | 1105 | wait_sb_inodes(sb); |
Jens Axboe | d8a8559 | 2009-09-02 12:34:32 +0200 | [diff] [blame] | 1106 | } |
| 1107 | EXPORT_SYMBOL(sync_inodes_sb); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1108 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1109 | /** |
Andrea Arcangeli | 7f04c26 | 2005-10-30 15:03:05 -0800 | [diff] [blame] | 1110 | * write_inode_now - write an inode to disk |
| 1111 | * @inode: inode to write to disk |
| 1112 | * @sync: whether the write should be synchronous or not |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1113 | * |
Andrea Arcangeli | 7f04c26 | 2005-10-30 15:03:05 -0800 | [diff] [blame] | 1114 | * This function commits an inode to disk immediately if it is dirty. This is |
| 1115 | * primarily needed by knfsd. |
| 1116 | * |
| 1117 | * 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] | 1118 | */ |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1119 | int write_inode_now(struct inode *inode, int sync) |
| 1120 | { |
| 1121 | int ret; |
| 1122 | struct writeback_control wbc = { |
| 1123 | .nr_to_write = LONG_MAX, |
Mike Galbraith | 18914b1 | 2008-02-08 04:20:23 -0800 | [diff] [blame] | 1124 | .sync_mode = sync ? WB_SYNC_ALL : WB_SYNC_NONE, |
OGAWA Hirofumi | 111ebb6 | 2006-06-23 02:03:26 -0700 | [diff] [blame] | 1125 | .range_start = 0, |
| 1126 | .range_end = LLONG_MAX, |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1127 | }; |
| 1128 | |
| 1129 | if (!mapping_cap_writeback_dirty(inode->i_mapping)) |
Andrew Morton | 49364ce | 2005-11-07 00:59:15 -0800 | [diff] [blame] | 1130 | wbc.nr_to_write = 0; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1131 | |
| 1132 | might_sleep(); |
| 1133 | spin_lock(&inode_lock); |
Christoph Hellwig | 01c0319 | 2009-06-08 13:35:40 +0200 | [diff] [blame] | 1134 | ret = writeback_single_inode(inode, &wbc); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1135 | spin_unlock(&inode_lock); |
| 1136 | if (sync) |
Joern Engel | 1c0eeaf | 2007-10-16 23:30:44 -0700 | [diff] [blame] | 1137 | inode_sync_wait(inode); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1138 | return ret; |
| 1139 | } |
| 1140 | EXPORT_SYMBOL(write_inode_now); |
| 1141 | |
| 1142 | /** |
| 1143 | * sync_inode - write an inode and its pages to disk. |
| 1144 | * @inode: the inode to sync |
| 1145 | * @wbc: controls the writeback mode |
| 1146 | * |
| 1147 | * sync_inode() will write an inode and its pages to disk. It will also |
| 1148 | * correctly update the inode on its superblock's dirty inode lists and will |
| 1149 | * update inode->i_state. |
| 1150 | * |
| 1151 | * The caller must have a ref on the inode. |
| 1152 | */ |
| 1153 | int sync_inode(struct inode *inode, struct writeback_control *wbc) |
| 1154 | { |
| 1155 | int ret; |
| 1156 | |
| 1157 | spin_lock(&inode_lock); |
Christoph Hellwig | 01c0319 | 2009-06-08 13:35:40 +0200 | [diff] [blame] | 1158 | ret = writeback_single_inode(inode, wbc); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1159 | spin_unlock(&inode_lock); |
| 1160 | return ret; |
| 1161 | } |
| 1162 | EXPORT_SYMBOL(sync_inode); |