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authorAndré Fabian Silva Delgado <emulatorman@parabola.nu>2015-08-05 17:04:01 -0300
committerAndré Fabian Silva Delgado <emulatorman@parabola.nu>2015-08-05 17:04:01 -0300
commit57f0f512b273f60d52568b8c6b77e17f5636edc0 (patch)
tree5e910f0e82173f4ef4f51111366a3f1299037a7b /fs/ext3/fsync.c
Initial import
Diffstat (limited to 'fs/ext3/fsync.c')
-rw-r--r--fs/ext3/fsync.c109
1 files changed, 109 insertions, 0 deletions
diff --git a/fs/ext3/fsync.c b/fs/ext3/fsync.c
new file mode 100644
index 000000000..1cb9c7e10
--- /dev/null
+++ b/fs/ext3/fsync.c
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+/*
+ * 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/blkdev.h>
+#include <linux/writeback.h>
+#include "ext3.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, loff_t start, loff_t end, int datasync)
+{
+ struct inode *inode = file->f_mapping->host;
+ 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;
+
+ trace_ext3_sync_file_enter(file, datasync);
+
+ if (inode->i_sb->s_flags & MS_RDONLY) {
+ /* Make sure that we read updated state */
+ smp_rmb();
+ if (EXT3_SB(inode->i_sb)->s_mount_state & EXT3_ERROR_FS)
+ return -EROFS;
+ return 0;
+ }
+ ret = filemap_write_and_wait_range(inode->i_mapping, start, end);
+ if (ret)
+ goto out;
+
+ 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)) {
+ ret = ext3_force_commit(inode->i_sb);
+ goto out;
+ }
+
+ 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) {
+ int err;
+
+ err = blkdev_issue_flush(inode->i_sb->s_bdev, GFP_KERNEL, NULL);
+ if (!ret)
+ ret = err;
+ }
+out:
+ trace_ext3_sync_file_exit(inode, ret);
+ return ret;
+}