/* * linux/fs/ext3/fsync.c * * Copyright (C) 1993 Stephen Tweedie (sct@redhat.com) * from * Copyright (C) 1992 Remy Card (card@masi.ibp.fr) * Laboratoire MASI - Institut Blaise Pascal * Universite Pierre et Marie Curie (Paris VI) * from * linux/fs/minix/truncate.c Copyright (C) 1991, 1992 Linus Torvalds * * ext3fs fsync primitive * * Big-endian to little-endian byte-swapping/bitmaps by * David S. Miller (davem@caip.rutgers.edu), 1995 * * Removed unnecessary code duplication for little endian machines * and excessive __inline__s. * Andi Kleen, 1997 * * Major simplications and cleanup - we only need to do the metadata, because * we can depend on generic_block_fdatasync() to sync the data blocks. */ #include <linux/time.h> #include <linux/blkdev.h> #include <linux/fs.h> #include <linux/sched.h> #include <linux/writeback.h> #include <linux/jbd.h> #include <linux/ext3_fs.h> #include <linux/ext3_jbd.h> /* * akpm: A new design for ext3_sync_file(). * * This is only called from sys_fsync(), sys_fdatasync() and sys_msync(). * There cannot be a transaction open by this task. * Another task could have dirtied this inode. Its data can be in any * state in the journalling system. * * What we do is just kick off a commit and wait on it. This will snapshot the * inode to disk. */ int ext3_sync_file(struct file * file, struct dentry *dentry, int datasync) { struct inode *inode = dentry->d_inode; struct ext3_inode_info *ei = EXT3_I(inode); journal_t *journal = EXT3_SB(inode->i_sb)->s_journal; int ret, needs_barrier = 0; tid_t commit_tid; if (inode->i_sb->s_flags & MS_RDONLY) return 0; J_ASSERT(ext3_journal_current_handle() == NULL); /* * data=writeback,ordered: * The caller's filemap_fdatawrite()/wait will sync the data. * Metadata is in the journal, we wait for a proper transaction * to commit here. * * data=journal: * filemap_fdatawrite won't do anything (the buffers are clean). * ext3_force_commit will write the file data into the journal and * will wait on that. * filemap_fdatawait() will encounter a ton of newly-dirtied pages * (they were dirtied by commit). But that's OK - the blocks are * safe in-journal, which is all fsync() needs to ensure. */ if (ext3_should_journal_data(inode)) return ext3_force_commit(inode->i_sb); if (datasync) commit_tid = atomic_read(&ei->i_datasync_tid); else commit_tid = atomic_read(&ei->i_sync_tid); if (test_opt(inode->i_sb, BARRIER) && !journal_trans_will_send_data_barrier(journal, commit_tid)) needs_barrier = 1; log_start_commit(journal, commit_tid); ret = log_wait_commit(journal, commit_tid); /* * In case we didn't commit a transaction, we have to flush * disk caches manually so that data really is on persistent * storage */ if (needs_barrier) blkdev_issue_flush(inode->i_sb->s_bdev, GFP_KERNEL, NULL, BLKDEV_IFL_WAIT); return ret; }