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| 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 | |
| 46 | int ext3_sync_file(struct file *file, int datasync) |
| 47 | { |
| 48 | struct inode *inode = file->f_mapping->host; |
| 49 | struct ext3_inode_info *ei = EXT3_I(inode); |
| 50 | journal_t *journal = EXT3_SB(inode->i_sb)->s_journal; |
| 51 | int ret, needs_barrier = 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 | return ext3_force_commit(inode->i_sb); |
| 75 | |
| 76 | if (datasync) |
| 77 | commit_tid = atomic_read(&ei->i_datasync_tid); |
| 78 | else |
| 79 | commit_tid = atomic_read(&ei->i_sync_tid); |
| 80 | |
| 81 | if (test_opt(inode->i_sb, BARRIER) && |
| 82 | !journal_trans_will_send_data_barrier(journal, commit_tid)) |
| 83 | needs_barrier = 1; |
| 84 | log_start_commit(journal, commit_tid); |
| 85 | ret = log_wait_commit(journal, commit_tid); |
| 86 | |
| 87 | /* |
| 88 | * In case we didn't commit a transaction, we have to flush |
| 89 | * disk caches manually so that data really is on persistent |
| 90 | * storage |
| 91 | */ |
| 92 | if (needs_barrier) |
| 93 | blkdev_issue_flush(inode->i_sb->s_bdev, GFP_KERNEL, NULL); |
| 94 | return ret; |
| 95 | } |
| 96 |
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