Branch data Line data Source code
1 : : /*
2 : : * linux/fs/ext4/fsync.c
3 : : *
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 : : *
12 : : * ext4fs fsync primitive
13 : : *
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>
29 : : #include <linux/jbd2.h>
30 : : #include <linux/blkdev.h>
31 : :
32 : : #include "ext4.h"
33 : : #include "ext4_jbd2.h"
34 : :
35 : : #include <trace/events/ext4.h>
36 : :
37 : : /*
38 : : * If we're not journaling and this is a just-created file, we have to
39 : : * sync our parent directory (if it was freshly created) since
40 : : * otherwise it will only be written by writeback, leaving a huge
41 : : * window during which a crash may lose the file. This may apply for
42 : : * the parent directory's parent as well, and so on recursively, if
43 : : * they are also freshly created.
44 : : */
45 : 0 : static int ext4_sync_parent(struct inode *inode)
46 : : {
47 : : struct dentry *dentry = NULL;
48 : : struct inode *next;
49 : : int ret = 0;
50 : :
51 [ # # ]: 0 : if (!ext4_test_inode_state(inode, EXT4_STATE_NEWENTRY))
52 : : return 0;
53 : 0 : inode = igrab(inode);
54 [ # # ]: 0 : while (ext4_test_inode_state(inode, EXT4_STATE_NEWENTRY)) {
55 : : ext4_clear_inode_state(inode, EXT4_STATE_NEWENTRY);
56 : 0 : dentry = d_find_any_alias(inode);
57 [ # # ]: 0 : if (!dentry)
58 : : break;
59 : 0 : next = igrab(dentry->d_parent->d_inode);
60 : 0 : dput(dentry);
61 [ # # ]: 0 : if (!next)
62 : : break;
63 : 0 : iput(inode);
64 : : inode = next;
65 : 0 : ret = sync_mapping_buffers(inode->i_mapping);
66 [ # # ]: 0 : if (ret)
67 : : break;
68 : 0 : ret = sync_inode_metadata(inode, 1);
69 [ # # ]: 0 : if (ret)
70 : : break;
71 : : }
72 : 0 : iput(inode);
73 : 0 : return ret;
74 : : }
75 : :
76 : : /*
77 : : * akpm: A new design for ext4_sync_file().
78 : : *
79 : : * This is only called from sys_fsync(), sys_fdatasync() and sys_msync().
80 : : * There cannot be a transaction open by this task.
81 : : * Another task could have dirtied this inode. Its data can be in any
82 : : * state in the journalling system.
83 : : *
84 : : * What we do is just kick off a commit and wait on it. This will snapshot the
85 : : * inode to disk.
86 : : */
87 : :
88 : 0 : int ext4_sync_file(struct file *file, loff_t start, loff_t end, int datasync)
89 : : {
90 : 28770 : struct inode *inode = file->f_mapping->host;
91 : : struct ext4_inode_info *ei = EXT4_I(inode);
92 : 28770 : journal_t *journal = EXT4_SB(inode->i_sb)->s_journal;
93 : : int ret = 0, err;
94 : : tid_t commit_tid;
95 : : bool needs_barrier = false;
96 : :
97 [ - + ]: 28770 : J_ASSERT(ext4_journal_current_handle() == NULL);
98 : :
99 : : trace_ext4_sync_file_enter(file, datasync);
100 : :
101 [ - + ]: 28759 : if (inode->i_sb->s_flags & MS_RDONLY) {
102 : : /* Make sure that we read updated s_mount_flags value */
103 : 0 : smp_rmb();
104 [ # # ]: 0 : if (EXT4_SB(inode->i_sb)->s_mount_flags & EXT4_MF_FS_ABORTED)
105 : : ret = -EROFS;
106 : : goto out;
107 : : }
108 : :
109 [ - + ]: 28759 : if (!journal) {
110 : 0 : ret = generic_file_fsync(file, start, end, datasync);
111 [ # # ][ # # ]: 0 : if (!ret && !hlist_empty(&inode->i_dentry))
112 : 0 : ret = ext4_sync_parent(inode);
113 : : goto out;
114 : : }
115 : :
116 : 28759 : ret = filemap_write_and_wait_range(inode->i_mapping, start, end);
117 [ + - ]: 28775 : if (ret)
118 : : return ret;
119 : : /*
120 : : * data=writeback,ordered:
121 : : * The caller's filemap_fdatawrite()/wait will sync the data.
122 : : * Metadata is in the journal, we wait for proper transaction to
123 : : * commit here.
124 : : *
125 : : * data=journal:
126 : : * filemap_fdatawrite won't do anything (the buffers are clean).
127 : : * ext4_force_commit will write the file data into the journal and
128 : : * will wait on that.
129 : : * filemap_fdatawait() will encounter a ton of newly-dirtied pages
130 : : * (they were dirtied by commit). But that's OK - the blocks are
131 : : * safe in-journal, which is all fsync() needs to ensure.
132 : : */
133 [ + + ]: 28775 : if (ext4_should_journal_data(inode)) {
134 : 82 : ret = ext4_force_commit(inode->i_sb);
135 : 82 : goto out;
136 : : }
137 : :
138 [ + + ]: 28693 : commit_tid = datasync ? ei->i_datasync_tid : ei->i_sync_tid;
139 [ + + + + ]: 57385 : if (journal->j_flags & JBD2_BARRIER &&
140 : 28684 : !jbd2_trans_will_send_data_barrier(journal, commit_tid))
141 : : needs_barrier = true;
142 : 28701 : ret = jbd2_complete_transaction(journal, commit_tid);
143 [ + + ]: 28690 : if (needs_barrier) {
144 : 1736 : err = blkdev_issue_flush(inode->i_sb->s_bdev, GFP_KERNEL, NULL);
145 [ + ]: 1736 : if (!ret)
146 : : ret = err;
147 : : }
148 : : out:
149 : : trace_ext4_sync_file_exit(inode, ret);
150 : 28774 : return ret;
151 : : }
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