[PATCH 1/3] block_write_full_page: Use synchronous writes for WBC_SYNC_ALL writebacks

Theodore Ts'o
2009-03-27T20:24:52Z

When doing synchronous writes because wbc->sync_mode is set to
WBC_SYNC_ALL, send the write request using WRITE_SYNC, so that we
don't unduly block system calls such as fsync().

Signed-off-by: "Theodore Ts'o" <tytso@mit.edu>
---
fs/buffer.c | 5 +++--
1 files changed, 3 insertions(+), 2 deletions(-)

diff --git a/fs/buffer.c b/fs/buffer.c
index 891e1c7..e7ebd95 100644
--- a/fs/buffer.c
+++ b/fs/buffer.c
@@ -1714,6 +1714,7 @@ static int __block_write_full_page(struct inode *inode, struct page *page,
struct buffer_head *bh, *head;
const unsigned blocksize = 1 << inode->i_blkbits;
int nr_underway = 0;
+ int write_op = (wbc->sync_mode == WB_SYNC_ALL ? WRITE_SYNC : WRITE);

BUG_ON(!PageLocked(page));

@@ -1805,7 +1806,7 @@ static int __block_write_full_page(struct inode *inode, struct page *page,
do {
struct buffer_head *next = bh->b_this_page;
if (buffer_async_write(bh)) {
- submit_bh(WRITE, bh);
+ submit_bh(write_op, bh);
nr_underway++;
}
bh = next;
@@ -1859,7 +1860,7 @@ recover:
struct buffer_head *next = bh->b_this_page;
if (buffer_async_write(bh)) {
clear_buffer_dirty(bh);
- submit_bh(WRITE, bh);
+ submit_bh(write_op, bh);
nr_underway++;
}
bh = next;
--
1.5.6.3