1ac27a0ecSDave Kleikamp /* 2617ba13bSMingming Cao * linux/fs/ext4/fsync.c 3ac27a0ecSDave Kleikamp * 4ac27a0ecSDave Kleikamp * Copyright (C) 1993 Stephen Tweedie (sct@redhat.com) 5ac27a0ecSDave Kleikamp * from 6ac27a0ecSDave Kleikamp * Copyright (C) 1992 Remy Card (card@masi.ibp.fr) 7ac27a0ecSDave Kleikamp * Laboratoire MASI - Institut Blaise Pascal 8ac27a0ecSDave Kleikamp * Universite Pierre et Marie Curie (Paris VI) 9ac27a0ecSDave Kleikamp * from 10ac27a0ecSDave Kleikamp * linux/fs/minix/truncate.c Copyright (C) 1991, 1992 Linus Torvalds 11ac27a0ecSDave Kleikamp * 12617ba13bSMingming Cao * ext4fs fsync primitive 13ac27a0ecSDave Kleikamp * 14ac27a0ecSDave Kleikamp * Big-endian to little-endian byte-swapping/bitmaps by 15ac27a0ecSDave Kleikamp * David S. Miller (davem@caip.rutgers.edu), 1995 16ac27a0ecSDave Kleikamp * 17ac27a0ecSDave Kleikamp * Removed unnecessary code duplication for little endian machines 18ac27a0ecSDave Kleikamp * and excessive __inline__s. 19ac27a0ecSDave Kleikamp * Andi Kleen, 1997 20ac27a0ecSDave Kleikamp * 21ac27a0ecSDave Kleikamp * Major simplications and cleanup - we only need to do the metadata, because 22ac27a0ecSDave Kleikamp * we can depend on generic_block_fdatasync() to sync the data blocks. 23ac27a0ecSDave Kleikamp */ 24ac27a0ecSDave Kleikamp 25ac27a0ecSDave Kleikamp #include <linux/time.h> 26ac27a0ecSDave Kleikamp #include <linux/fs.h> 27ac27a0ecSDave Kleikamp #include <linux/sched.h> 28ac27a0ecSDave Kleikamp #include <linux/writeback.h> 29dab291afSMingming Cao #include <linux/jbd2.h> 30d755fb38SEric Sandeen #include <linux/blkdev.h> 319bffad1eSTheodore Ts'o 323dcf5451SChristoph Hellwig #include "ext4.h" 333dcf5451SChristoph Hellwig #include "ext4_jbd2.h" 34ac27a0ecSDave Kleikamp 359bffad1eSTheodore Ts'o #include <trace/events/ext4.h> 369bffad1eSTheodore Ts'o 37ac27a0ecSDave Kleikamp /* 38617ba13bSMingming Cao * akpm: A new design for ext4_sync_file(). 39ac27a0ecSDave Kleikamp * 40ac27a0ecSDave Kleikamp * This is only called from sys_fsync(), sys_fdatasync() and sys_msync(). 41ac27a0ecSDave Kleikamp * There cannot be a transaction open by this task. 42ac27a0ecSDave Kleikamp * Another task could have dirtied this inode. Its data can be in any 43ac27a0ecSDave Kleikamp * state in the journalling system. 44ac27a0ecSDave Kleikamp * 45ac27a0ecSDave Kleikamp * What we do is just kick off a commit and wait on it. This will snapshot the 46ac27a0ecSDave Kleikamp * inode to disk. 478d5d02e6SMingming Cao * 488d5d02e6SMingming Cao * i_mutex lock is held when entering and exiting this function 49ac27a0ecSDave Kleikamp */ 50ac27a0ecSDave Kleikamp 51617ba13bSMingming Cao int ext4_sync_file(struct file *file, struct dentry *dentry, int datasync) 52ac27a0ecSDave Kleikamp { 53ac27a0ecSDave Kleikamp struct inode *inode = dentry->d_inode; 54d755fb38SEric Sandeen journal_t *journal = EXT4_SB(inode->i_sb)->s_journal; 55fe188c0eSTheodore Ts'o int err, ret = 0; 56ac27a0ecSDave Kleikamp 57ac39849dSAneesh Kumar K.V J_ASSERT(ext4_journal_current_handle() == NULL); 58ac27a0ecSDave Kleikamp 599bffad1eSTheodore Ts'o trace_ext4_sync_file(file, dentry, datasync); 60ede86cc4STheodore Ts'o 618d5d02e6SMingming Cao ret = flush_aio_dio_completed_IO(inode); 628d5d02e6SMingming Cao if (ret < 0) 638d5d02e6SMingming Cao goto out; 64ac27a0ecSDave Kleikamp /* 65ac27a0ecSDave Kleikamp * data=writeback: 66ac27a0ecSDave Kleikamp * The caller's filemap_fdatawrite()/wait will sync the data. 67ac27a0ecSDave Kleikamp * sync_inode() will sync the metadata 68ac27a0ecSDave Kleikamp * 69ac27a0ecSDave Kleikamp * data=ordered: 70ac27a0ecSDave Kleikamp * The caller's filemap_fdatawrite() will write the data and 71ac27a0ecSDave Kleikamp * sync_inode() will write the inode if it is dirty. Then the caller's 72ac27a0ecSDave Kleikamp * filemap_fdatawait() will wait on the pages. 73ac27a0ecSDave Kleikamp * 74ac27a0ecSDave Kleikamp * data=journal: 75ac27a0ecSDave Kleikamp * filemap_fdatawrite won't do anything (the buffers are clean). 76617ba13bSMingming Cao * ext4_force_commit will write the file data into the journal and 77ac27a0ecSDave Kleikamp * will wait on that. 78ac27a0ecSDave Kleikamp * filemap_fdatawait() will encounter a ton of newly-dirtied pages 79ac27a0ecSDave Kleikamp * (they were dirtied by commit). But that's OK - the blocks are 80ac27a0ecSDave Kleikamp * safe in-journal, which is all fsync() needs to ensure. 81ac27a0ecSDave Kleikamp */ 82617ba13bSMingming Cao if (ext4_should_journal_data(inode)) { 83617ba13bSMingming Cao ret = ext4_force_commit(inode->i_sb); 84ac27a0ecSDave Kleikamp goto out; 85ac27a0ecSDave Kleikamp } 86ac27a0ecSDave Kleikamp 87fe188c0eSTheodore Ts'o if (!journal) 88fe188c0eSTheodore Ts'o ret = sync_mapping_buffers(inode->i_mapping); 89fe188c0eSTheodore Ts'o 9053c550e9SHisashi Hifumi if (datasync && !(inode->i_state & I_DIRTY_DATASYNC)) 9153c550e9SHisashi Hifumi goto out; 9253c550e9SHisashi Hifumi 93ac27a0ecSDave Kleikamp /* 94ac27a0ecSDave Kleikamp * The VFS has written the file data. If the inode is unaltered 95ac27a0ecSDave Kleikamp * then we need not start a commit. 96ac27a0ecSDave Kleikamp */ 97ac27a0ecSDave Kleikamp if (inode->i_state & (I_DIRTY_SYNC|I_DIRTY_DATASYNC)) { 98ac27a0ecSDave Kleikamp struct writeback_control wbc = { 99ac27a0ecSDave Kleikamp .sync_mode = WB_SYNC_ALL, 100ac27a0ecSDave Kleikamp .nr_to_write = 0, /* sys_fsync did this */ 101ac27a0ecSDave Kleikamp }; 102fe188c0eSTheodore Ts'o err = sync_inode(inode, &wbc); 103fe188c0eSTheodore Ts'o if (ret == 0) 104fe188c0eSTheodore Ts'o ret = err; 105ac27a0ecSDave Kleikamp } 106ac27a0ecSDave Kleikamp out: 1075f3481e9SChristoph Hellwig if (journal && (journal->j_flags & JBD2_BARRIER)) 1085f3481e9SChristoph Hellwig blkdev_issue_flush(inode->i_sb->s_bdev, NULL); 109ac27a0ecSDave Kleikamp return ret; 110ac27a0ecSDave Kleikamp } 111