1/* 2 * linux/fs/ext3/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 * ext3fs 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/blkdev.h> 27#include <linux/fs.h> 28#include <linux/sched.h> 29#include <linux/writeback.h> 30#include <linux/jbd.h> 31#include <linux/ext3_fs.h> 32#include <linux/ext3_jbd.h> 33 34/* 35 * akpm: A new design for ext3_sync_file(). 36 * 37 * This is only called from sys_fsync(), sys_fdatasync() and sys_msync(). 38 * There cannot be a transaction open by this task. 39 * Another task could have dirtied this inode. Its data can be in any 40 * state in the journalling system. 41 * 42 * What we do is just kick off a commit and wait on it. This will snapshot the 43 * inode to disk. 44 */ 45 46int ext3_sync_file(struct file * file, struct dentry *dentry, int datasync) 47{ 48 struct inode *inode = dentry->d_inode; 49 struct ext3_inode_info *ei = EXT3_I(inode); 50 journal_t *journal = EXT3_SB(inode->i_sb)->s_journal; 51 int ret = 0; 52 tid_t commit_tid; 53 54 if (inode->i_sb->s_flags & MS_RDONLY) 55 return 0; 56 57 J_ASSERT(ext3_journal_current_handle() == NULL); 58 59 /* 60 * data=writeback,ordered: 61 * The caller's filemap_fdatawrite()/wait will sync the data. 62 * Metadata is in the journal, we wait for a proper transaction 63 * to commit here. 64 * 65 * data=journal: 66 * filemap_fdatawrite won't do anything (the buffers are clean). 67 * ext3_force_commit will write the file data into the journal and 68 * will wait on that. 69 * filemap_fdatawait() will encounter a ton of newly-dirtied pages 70 * (they were dirtied by commit). But that's OK - the blocks are 71 * safe in-journal, which is all fsync() needs to ensure. 72 */ 73 if (ext3_should_journal_data(inode)) { 74 ret = ext3_force_commit(inode->i_sb); 75 goto out; 76 } 77 78 if (datasync) 79 commit_tid = atomic_read(&ei->i_datasync_tid); 80 else 81 commit_tid = atomic_read(&ei->i_sync_tid); 82 83 if (log_start_commit(journal, commit_tid)) { 84 log_wait_commit(journal, commit_tid); 85 goto out; 86 } 87 88 /* 89 * In case we didn't commit a transaction, we have to flush 90 * disk caches manually so that data really is on persistent 91 * storage 92 */ 93 if (test_opt(inode->i_sb, BARRIER)) 94 blkdev_issue_flush(inode->i_sb->s_bdev, NULL); 95out: 96 return ret; 97} 98