[PATCH] add -o flush for fat
Fat is commonly used on removable media. Mounting with -o flush tells the
FS to write things to disk as quickly as possible. It is like -o sync, but
much faster (and not as safe).
Signed-off-by: Chris Mason <mason@suse.com>
Cc: OGAWA Hirofumi <hirofumi@mail.parknet.co.jp>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
diff --git a/fs/fat/inode.c b/fs/fat/inode.c
index ab96ae8..0457380 100644
--- a/fs/fat/inode.c
+++ b/fs/fat/inode.c
@@ -24,6 +24,7 @@
#include <linux/vfs.h>
#include <linux/parser.h>
#include <linux/uio.h>
+#include <linux/writeback.h>
#include <asm/unaligned.h>
#ifndef CONFIG_FAT_DEFAULT_IOCHARSET
@@ -853,7 +854,7 @@
Opt_charset, Opt_shortname_lower, Opt_shortname_win95,
Opt_shortname_winnt, Opt_shortname_mixed, Opt_utf8_no, Opt_utf8_yes,
Opt_uni_xl_no, Opt_uni_xl_yes, Opt_nonumtail_no, Opt_nonumtail_yes,
- Opt_obsolate, Opt_err,
+ Opt_obsolate, Opt_flush, Opt_err,
};
static match_table_t fat_tokens = {
@@ -885,7 +886,8 @@
{Opt_obsolate, "cvf_format=%20s"},
{Opt_obsolate, "cvf_options=%100s"},
{Opt_obsolate, "posix"},
- {Opt_err, NULL}
+ {Opt_flush, "flush"},
+ {Opt_err, NULL},
};
static match_table_t msdos_tokens = {
{Opt_nodots, "nodots"},
@@ -1026,6 +1028,9 @@
return 0;
opts->codepage = option;
break;
+ case Opt_flush:
+ opts->flush = 1;
+ break;
/* msdos specific */
case Opt_dots:
@@ -1425,6 +1430,56 @@
EXPORT_SYMBOL_GPL(fat_fill_super);
+/*
+ * helper function for fat_flush_inodes. This writes both the inode
+ * and the file data blocks, waiting for in flight data blocks before
+ * the start of the call. It does not wait for any io started
+ * during the call
+ */
+static int writeback_inode(struct inode *inode)
+{
+
+ int ret;
+ struct address_space *mapping = inode->i_mapping;
+ struct writeback_control wbc = {
+ .sync_mode = WB_SYNC_NONE,
+ .nr_to_write = 0,
+ };
+ /* if we used WB_SYNC_ALL, sync_inode waits for the io for the
+ * inode to finish. So WB_SYNC_NONE is sent down to sync_inode
+ * and filemap_fdatawrite is used for the data blocks
+ */
+ ret = sync_inode(inode, &wbc);
+ if (!ret)
+ ret = filemap_fdatawrite(mapping);
+ return ret;
+}
+
+/*
+ * write data and metadata corresponding to i1 and i2. The io is
+ * started but we do not wait for any of it to finish.
+ *
+ * filemap_flush is used for the block device, so if there is a dirty
+ * page for a block already in flight, we will not wait and start the
+ * io over again
+ */
+int fat_flush_inodes(struct super_block *sb, struct inode *i1, struct inode *i2)
+{
+ int ret = 0;
+ if (!MSDOS_SB(sb)->options.flush)
+ return 0;
+ if (i1)
+ ret = writeback_inode(i1);
+ if (!ret && i2)
+ ret = writeback_inode(i2);
+ if (!ret && sb) {
+ struct address_space *mapping = sb->s_bdev->bd_inode->i_mapping;
+ ret = filemap_flush(mapping);
+ }
+ return ret;
+}
+EXPORT_SYMBOL_GPL(fat_flush_inodes);
+
static int __init init_fat_fs(void)
{
int err;