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/blkdev.h> 26#include <linux/writeback.h> 27#include "ext3.h" 28 29/* 30 * akpm: A new design for ext3_sync_file(). 31 * 32 * This is only called from sys_fsync(), sys_fdatasync() and sys_msync(). 33 * There cannot be a transaction open by this task. 34 * Another task could have dirtied this inode. Its data can be in any 35 * state in the journalling system. 36 * 37 * What we do is just kick off a commit and wait on it. This will snapshot the 38 * inode to disk. 39 */ 40 41int ext3_sync_file(struct file *file, loff_t start, loff_t end, int datasync) 42{ 43 struct inode *inode = file->f_mapping->host; 44 struct ext3_inode_info *ei = EXT3_I(inode); 45 journal_t *journal = EXT3_SB(inode->i_sb)->s_journal; 46 int ret, needs_barrier = 0; 47 tid_t commit_tid; 48 49 trace_ext3_sync_file_enter(file, datasync); 50 51 if (inode->i_sb->s_flags & MS_RDONLY) 52 return 0; 53 54 ret = filemap_write_and_wait_range(inode->i_mapping, start, end); 55 if (ret) 56 goto out; 57 58 J_ASSERT(ext3_journal_current_handle() == NULL); 59 60 /* 61 * data=writeback,ordered: 62 * The caller's filemap_fdatawrite()/wait will sync the data. 63 * Metadata is in the journal, we wait for a proper transaction 64 * to commit here. 65 * 66 * data=journal: 67 * filemap_fdatawrite won't do anything (the buffers are clean). 68 * ext3_force_commit will write the file data into the journal and 69 * will wait on that. 70 * filemap_fdatawait() will encounter a ton of newly-dirtied pages 71 * (they were dirtied by commit). But that's OK - the blocks are 72 * safe in-journal, which is all fsync() needs to ensure. 73 */ 74 if (ext3_should_journal_data(inode)) { 75 ret = ext3_force_commit(inode->i_sb); 76 goto out; 77 } 78 79 if (datasync) 80 commit_tid = atomic_read(&ei->i_datasync_tid); 81 else 82 commit_tid = atomic_read(&ei->i_sync_tid); 83 84 if (test_opt(inode->i_sb, BARRIER) && 85 !journal_trans_will_send_data_barrier(journal, commit_tid)) 86 needs_barrier = 1; 87 log_start_commit(journal, commit_tid); 88 ret = log_wait_commit(journal, commit_tid); 89 90 /* 91 * In case we didn't commit a transaction, we have to flush 92 * disk caches manually so that data really is on persistent 93 * storage 94 */ 95 if (needs_barrier) { 96 int err; 97 98 err = blkdev_issue_flush(inode->i_sb->s_bdev, GFP_KERNEL, NULL); 99 if (!ret) 100 ret = err; 101 } 102out: 103 trace_ext3_sync_file_exit(inode, ret); 104 return ret; 105} 106