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> 313dcf5451SChristoph Hellwig #include "ext4.h" 323dcf5451SChristoph Hellwig #include "ext4_jbd2.h" 33ac27a0ecSDave Kleikamp 34ac27a0ecSDave Kleikamp /* 35617ba13bSMingming Cao * akpm: A new design for ext4_sync_file(). 36ac27a0ecSDave Kleikamp * 37ac27a0ecSDave Kleikamp * This is only called from sys_fsync(), sys_fdatasync() and sys_msync(). 38ac27a0ecSDave Kleikamp * There cannot be a transaction open by this task. 39ac27a0ecSDave Kleikamp * Another task could have dirtied this inode. Its data can be in any 40ac27a0ecSDave Kleikamp * state in the journalling system. 41ac27a0ecSDave Kleikamp * 42ac27a0ecSDave Kleikamp * What we do is just kick off a commit and wait on it. This will snapshot the 43ac27a0ecSDave Kleikamp * inode to disk. 44ac27a0ecSDave Kleikamp */ 45ac27a0ecSDave Kleikamp 46617ba13bSMingming Cao int ext4_sync_file(struct file * file, struct dentry *dentry, int datasync) 47ac27a0ecSDave Kleikamp { 48ac27a0ecSDave Kleikamp struct inode *inode = dentry->d_inode; 49d755fb38SEric Sandeen journal_t *journal = EXT4_SB(inode->i_sb)->s_journal; 50ac27a0ecSDave Kleikamp int ret = 0; 51ac27a0ecSDave Kleikamp 52ac39849dSAneesh Kumar K.V J_ASSERT(ext4_journal_current_handle() == NULL); 53ac27a0ecSDave Kleikamp 54ac27a0ecSDave Kleikamp /* 55ac27a0ecSDave Kleikamp * data=writeback: 56ac27a0ecSDave Kleikamp * The caller's filemap_fdatawrite()/wait will sync the data. 57ac27a0ecSDave Kleikamp * sync_inode() will sync the metadata 58ac27a0ecSDave Kleikamp * 59ac27a0ecSDave Kleikamp * data=ordered: 60ac27a0ecSDave Kleikamp * The caller's filemap_fdatawrite() will write the data and 61ac27a0ecSDave Kleikamp * sync_inode() will write the inode if it is dirty. Then the caller's 62ac27a0ecSDave Kleikamp * filemap_fdatawait() will wait on the pages. 63ac27a0ecSDave Kleikamp * 64ac27a0ecSDave Kleikamp * data=journal: 65ac27a0ecSDave Kleikamp * filemap_fdatawrite won't do anything (the buffers are clean). 66617ba13bSMingming Cao * ext4_force_commit will write the file data into the journal and 67ac27a0ecSDave Kleikamp * will wait on that. 68ac27a0ecSDave Kleikamp * filemap_fdatawait() will encounter a ton of newly-dirtied pages 69ac27a0ecSDave Kleikamp * (they were dirtied by commit). But that's OK - the blocks are 70ac27a0ecSDave Kleikamp * safe in-journal, which is all fsync() needs to ensure. 71ac27a0ecSDave Kleikamp */ 72617ba13bSMingming Cao if (ext4_should_journal_data(inode)) { 73617ba13bSMingming Cao ret = ext4_force_commit(inode->i_sb); 74ac27a0ecSDave Kleikamp goto out; 75ac27a0ecSDave Kleikamp } 76ac27a0ecSDave Kleikamp 7753c550e9SHisashi Hifumi if (datasync && !(inode->i_state & I_DIRTY_DATASYNC)) 7853c550e9SHisashi Hifumi goto out; 7953c550e9SHisashi Hifumi 80ac27a0ecSDave Kleikamp /* 81ac27a0ecSDave Kleikamp * The VFS has written the file data. If the inode is unaltered 82ac27a0ecSDave Kleikamp * then we need not start a commit. 83ac27a0ecSDave Kleikamp */ 84ac27a0ecSDave Kleikamp if (inode->i_state & (I_DIRTY_SYNC|I_DIRTY_DATASYNC)) { 85ac27a0ecSDave Kleikamp struct writeback_control wbc = { 86ac27a0ecSDave Kleikamp .sync_mode = WB_SYNC_ALL, 87ac27a0ecSDave Kleikamp .nr_to_write = 0, /* sys_fsync did this */ 88ac27a0ecSDave Kleikamp }; 89ac27a0ecSDave Kleikamp ret = sync_inode(inode, &wbc); 90d755fb38SEric Sandeen if (journal && (journal->j_flags & JBD2_BARRIER)) 91d755fb38SEric Sandeen blkdev_issue_flush(inode->i_sb->s_bdev, NULL); 92ac27a0ecSDave Kleikamp } 93ac27a0ecSDave Kleikamp out: 94ac27a0ecSDave Kleikamp return ret; 95ac27a0ecSDave Kleikamp } 96