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Dave Kleikampac27a0e2006-10-11 01:20:50 -07001/*
Mingming Cao617ba132006-10-11 01:20:53 -07002 * linux/fs/ext4/fsync.c
Dave Kleikampac27a0e2006-10-11 01:20:50 -07003 *
4 * Copyright (C) 1993 Stephen Tweedie (sct@redhat.com)
5 * from
6 * Copyright (C) 1992 Remy Card (card@masi.ibp.fr)
7 * Laboratoire MASI - Institut Blaise Pascal
8 * Universite Pierre et Marie Curie (Paris VI)
9 * from
10 * linux/fs/minix/truncate.c Copyright (C) 1991, 1992 Linus Torvalds
11 *
Mingming Cao617ba132006-10-11 01:20:53 -070012 * ext4fs fsync primitive
Dave Kleikampac27a0e2006-10-11 01:20:50 -070013 *
14 * Big-endian to little-endian byte-swapping/bitmaps by
15 * David S. Miller (davem@caip.rutgers.edu), 1995
16 *
17 * Removed unnecessary code duplication for little endian machines
18 * and excessive __inline__s.
19 * Andi Kleen, 1997
20 *
21 * Major simplications and cleanup - we only need to do the metadata, because
22 * we can depend on generic_block_fdatasync() to sync the data blocks.
23 */
24
25#include <linux/time.h>
26#include <linux/fs.h>
27#include <linux/sched.h>
28#include <linux/writeback.h>
Mingming Caodab291a2006-10-11 01:21:01 -070029#include <linux/jbd2.h>
Eric Sandeend755fb32008-07-11 19:27:31 -040030#include <linux/blkdev.h>
Theodore Ts'o9bffad12009-06-17 11:48:11 -040031
Christoph Hellwig3dcf5452008-04-29 18:13:32 -040032#include "ext4.h"
33#include "ext4_jbd2.h"
Dave Kleikampac27a0e2006-10-11 01:20:50 -070034
Theodore Ts'o9bffad12009-06-17 11:48:11 -040035#include <trace/events/ext4.h>
36
Theodore Ts'o4a873a42010-10-27 21:30:14 -040037static void dump_completed_IO(struct inode * inode)
38{
39#ifdef EXT4_DEBUG
40 struct list_head *cur, *before, *after;
41 ext4_io_end_t *io, *io0, *io1;
42 unsigned long flags;
43
44 if (list_empty(&EXT4_I(inode)->i_completed_io_list)){
45 ext4_debug("inode %lu completed_io list is empty\n", inode->i_ino);
46 return;
47 }
48
49 ext4_debug("Dump inode %lu completed_io list \n", inode->i_ino);
50 spin_lock_irqsave(&EXT4_I(inode)->i_completed_io_lock, flags);
51 list_for_each_entry(io, &EXT4_I(inode)->i_completed_io_list, list){
52 cur = &io->list;
53 before = cur->prev;
54 io0 = container_of(before, ext4_io_end_t, list);
55 after = cur->next;
56 io1 = container_of(after, ext4_io_end_t, list);
57
58 ext4_debug("io 0x%p from inode %lu,prev 0x%p,next 0x%p\n",
59 io, inode->i_ino, io0, io1);
60 }
61 spin_unlock_irqrestore(&EXT4_I(inode)->i_completed_io_lock, flags);
62#endif
63}
64
65/*
66 * This function is called from ext4_sync_file().
67 *
68 * When IO is completed, the work to convert unwritten extents to
69 * written is queued on workqueue but may not get immediately
70 * scheduled. When fsync is called, we need to ensure the
71 * conversion is complete before fsync returns.
72 * The inode keeps track of a list of pending/completed IO that
73 * might needs to do the conversion. This function walks through
74 * the list and convert the related unwritten extents for completed IO
75 * to written.
76 * The function return the number of pending IOs on success.
77 */
Jiaying Zhang3889fd52011-01-10 12:47:05 -050078extern int ext4_flush_completed_IO(struct inode *inode)
Theodore Ts'o4a873a42010-10-27 21:30:14 -040079{
80 ext4_io_end_t *io;
81 struct ext4_inode_info *ei = EXT4_I(inode);
82 unsigned long flags;
83 int ret = 0;
84 int ret2 = 0;
85
86 if (list_empty(&ei->i_completed_io_list))
87 return ret;
88
89 dump_completed_IO(inode);
90 spin_lock_irqsave(&ei->i_completed_io_lock, flags);
91 while (!list_empty(&ei->i_completed_io_list)){
92 io = list_entry(ei->i_completed_io_list.next,
93 ext4_io_end_t, list);
94 /*
95 * Calling ext4_end_io_nolock() to convert completed
96 * IO to written.
97 *
98 * When ext4_sync_file() is called, run_queue() may already
99 * about to flush the work corresponding to this io structure.
100 * It will be upset if it founds the io structure related
101 * to the work-to-be schedule is freed.
102 *
103 * Thus we need to keep the io structure still valid here after
Lucas De Marchi25985ed2011-03-30 22:57:33 -0300104 * conversion finished. The io structure has a flag to
Theodore Ts'o4a873a42010-10-27 21:30:14 -0400105 * avoid double converting from both fsync and background work
106 * queue work.
107 */
108 spin_unlock_irqrestore(&ei->i_completed_io_lock, flags);
109 ret = ext4_end_io_nolock(io);
110 spin_lock_irqsave(&ei->i_completed_io_lock, flags);
111 if (ret < 0)
112 ret2 = ret;
113 else
114 list_del_init(&io->list);
115 }
116 spin_unlock_irqrestore(&ei->i_completed_io_lock, flags);
117 return (ret2 < 0) ? ret2 : 0;
118}
119
Dave Kleikampac27a0e2006-10-11 01:20:50 -0700120/*
Frank Mayhar14ece102010-05-17 08:00:00 -0400121 * If we're not journaling and this is a just-created file, we have to
122 * sync our parent directory (if it was freshly created) since
123 * otherwise it will only be written by writeback, leaving a huge
124 * window during which a crash may lose the file. This may apply for
125 * the parent directory's parent as well, and so on recursively, if
126 * they are also freshly created.
127 */
Curt Wohlgemuth0893ed42011-04-10 22:05:31 -0400128static int ext4_sync_parent(struct inode *inode)
Frank Mayhar14ece102010-05-17 08:00:00 -0400129{
Curt Wohlgemuth0893ed42011-04-10 22:05:31 -0400130 struct writeback_control wbc;
Frank Mayhar14ece102010-05-17 08:00:00 -0400131 struct dentry *dentry = NULL;
Curt Wohlgemuth0893ed42011-04-10 22:05:31 -0400132 int ret = 0;
Frank Mayhar14ece102010-05-17 08:00:00 -0400133
134 while (inode && ext4_test_inode_state(inode, EXT4_STATE_NEWENTRY)) {
135 ext4_clear_inode_state(inode, EXT4_STATE_NEWENTRY);
136 dentry = list_entry(inode->i_dentry.next,
137 struct dentry, d_alias);
138 if (!dentry || !dentry->d_parent || !dentry->d_parent->d_inode)
139 break;
140 inode = dentry->d_parent->d_inode;
Curt Wohlgemuth0893ed42011-04-10 22:05:31 -0400141 ret = sync_mapping_buffers(inode->i_mapping);
142 if (ret)
143 break;
144 memset(&wbc, 0, sizeof(wbc));
145 wbc.sync_mode = WB_SYNC_ALL;
146 wbc.nr_to_write = 0; /* only write out the inode */
147 ret = sync_inode(inode, &wbc);
148 if (ret)
149 break;
Frank Mayhar14ece102010-05-17 08:00:00 -0400150 }
Curt Wohlgemuth0893ed42011-04-10 22:05:31 -0400151 return ret;
Frank Mayhar14ece102010-05-17 08:00:00 -0400152}
153
154/*
Mingming Cao617ba132006-10-11 01:20:53 -0700155 * akpm: A new design for ext4_sync_file().
Dave Kleikampac27a0e2006-10-11 01:20:50 -0700156 *
157 * This is only called from sys_fsync(), sys_fdatasync() and sys_msync().
158 * There cannot be a transaction open by this task.
159 * Another task could have dirtied this inode. Its data can be in any
160 * state in the journalling system.
161 *
162 * What we do is just kick off a commit and wait on it. This will snapshot the
163 * inode to disk.
Mingming Cao8d5d02e2009-09-28 15:48:29 -0400164 *
165 * i_mutex lock is held when entering and exiting this function
Dave Kleikampac27a0e2006-10-11 01:20:50 -0700166 */
167
Christoph Hellwig7ea80852010-05-26 17:53:25 +0200168int ext4_sync_file(struct file *file, int datasync)
Dave Kleikampac27a0e2006-10-11 01:20:50 -0700169{
Christoph Hellwig7ea80852010-05-26 17:53:25 +0200170 struct inode *inode = file->f_mapping->host;
Jan Karab436b9b2009-12-08 23:51:10 -0500171 struct ext4_inode_info *ei = EXT4_I(inode);
Eric Sandeend755fb32008-07-11 19:27:31 -0400172 journal_t *journal = EXT4_SB(inode->i_sb)->s_journal;
Jan Karab436b9b2009-12-08 23:51:10 -0500173 int ret;
174 tid_t commit_tid;
Dave Kleikampac27a0e2006-10-11 01:20:50 -0700175
Aneesh Kumar K.Vac398492007-10-16 18:38:25 -0400176 J_ASSERT(ext4_journal_current_handle() == NULL);
Dave Kleikampac27a0e2006-10-11 01:20:50 -0700177
Jiaying Zhang0562e0b2011-03-21 21:38:05 -0400178 trace_ext4_sync_file_enter(file, datasync);
Theodore Ts'oede86cc2008-10-05 20:50:06 -0400179
Jan Karab436b9b2009-12-08 23:51:10 -0500180 if (inode->i_sb->s_flags & MS_RDONLY)
181 return 0;
182
Jiaying Zhang3889fd52011-01-10 12:47:05 -0500183 ret = ext4_flush_completed_IO(inode);
Mingming Cao8d5d02e2009-09-28 15:48:29 -0400184 if (ret < 0)
Jiaying Zhang0562e0b2011-03-21 21:38:05 -0400185 goto out;
Theodore Ts'o60e66792010-05-17 07:00:00 -0400186
Frank Mayhar14ece102010-05-17 08:00:00 -0400187 if (!journal) {
Christoph Hellwig1b061d92010-05-26 17:53:41 +0200188 ret = generic_file_fsync(file, datasync);
Frank Mayhar14ece102010-05-17 08:00:00 -0400189 if (!ret && !list_empty(&inode->i_dentry))
Curt Wohlgemuth0893ed42011-04-10 22:05:31 -0400190 ret = ext4_sync_parent(inode);
Jiaying Zhang0562e0b2011-03-21 21:38:05 -0400191 goto out;
Frank Mayhar14ece102010-05-17 08:00:00 -0400192 }
Jan Karab436b9b2009-12-08 23:51:10 -0500193
Dave Kleikampac27a0e2006-10-11 01:20:50 -0700194 /*
Jan Karab436b9b2009-12-08 23:51:10 -0500195 * data=writeback,ordered:
Dave Kleikampac27a0e2006-10-11 01:20:50 -0700196 * The caller's filemap_fdatawrite()/wait will sync the data.
Jan Karab436b9b2009-12-08 23:51:10 -0500197 * Metadata is in the journal, we wait for proper transaction to
198 * commit here.
Dave Kleikampac27a0e2006-10-11 01:20:50 -0700199 *
200 * data=journal:
201 * filemap_fdatawrite won't do anything (the buffers are clean).
Mingming Cao617ba132006-10-11 01:20:53 -0700202 * ext4_force_commit will write the file data into the journal and
Dave Kleikampac27a0e2006-10-11 01:20:50 -0700203 * will wait on that.
204 * filemap_fdatawait() will encounter a ton of newly-dirtied pages
205 * (they were dirtied by commit). But that's OK - the blocks are
206 * safe in-journal, which is all fsync() needs to ensure.
207 */
Jiaying Zhang0562e0b2011-03-21 21:38:05 -0400208 if (ext4_should_journal_data(inode)) {
209 ret = ext4_force_commit(inode->i_sb);
210 goto out;
211 }
Dave Kleikampac27a0e2006-10-11 01:20:50 -0700212
Jan Karab436b9b2009-12-08 23:51:10 -0500213 commit_tid = datasync ? ei->i_datasync_tid : ei->i_sync_tid;
Theodore Ts'occ3e1be2009-12-23 06:52:08 -0500214 if (jbd2_log_start_commit(journal, commit_tid)) {
215 /*
216 * When the journal is on a different device than the
217 * fs data disk, we need to issue the barrier in
218 * writeback mode. (In ordered mode, the jbd2 layer
219 * will take care of issuing the barrier. In
220 * data=journal, all of the data blocks are written to
221 * the journal device.)
222 */
223 if (ext4_should_writeback_data(inode) &&
224 (journal->j_fs_dev != journal->j_dev) &&
225 (journal->j_flags & JBD2_BARRIER))
Dmitry Monakhovfbd9b092010-04-28 17:55:06 +0400226 blkdev_issue_flush(inode->i_sb->s_bdev, GFP_KERNEL,
Christoph Hellwigdd3932e2010-09-16 20:51:46 +0200227 NULL);
Dmitry Monakhov0671e702010-05-10 00:00:00 -0400228 ret = jbd2_log_wait_commit(journal, commit_tid);
Theodore Ts'occ3e1be2009-12-23 06:52:08 -0500229 } else if (journal->j_flags & JBD2_BARRIER)
Christoph Hellwigdd3932e2010-09-16 20:51:46 +0200230 blkdev_issue_flush(inode->i_sb->s_bdev, GFP_KERNEL, NULL);
Jiaying Zhang0562e0b2011-03-21 21:38:05 -0400231 out:
232 trace_ext4_sync_file_exit(inode, ret);
Dave Kleikampac27a0e2006-10-11 01:20:50 -0700233 return ret;
234}