aboutsummaryrefslogtreecommitdiffstats
path: root/fs/buffer.c
diff options
context:
space:
mode:
authorChristoph Hellwig <hch@lst.de>2010-08-11 17:06:24 +0200
committerAl Viro <viro@zeniv.linux.org.uk>2010-08-18 01:09:01 -0400
commit9cb569d601e0b93e01c20a22872270ec663b75f6 (patch)
tree80b2568fae48018806e82f8884062dae8a5494ae /fs/buffer.c
parent87e99511ea54510ffb60b98001d108794d5037f8 (diff)
downloadmrst-s0i3-test-9cb569d601e0b93e01c20a22872270ec663b75f6.tar.gz
mrst-s0i3-test-9cb569d601e0b93e01c20a22872270ec663b75f6.tar.xz
mrst-s0i3-test-9cb569d601e0b93e01c20a22872270ec663b75f6.zip
remove SWRITE* I/O types
These flags aren't real I/O types, but tell ll_rw_block to always lock the buffer instead of giving up on a failed trylock. Instead add a new write_dirty_buffer helper that implements this semantic and use it from the existing SWRITE* callers. Note that the ll_rw_block code had a bug where it didn't promote WRITE_SYNC_PLUG properly, which this patch fixes. In the ufs code clean up the helper that used to call ll_rw_block to mirror sync_dirty_buffer, which is the function it implements for compound buffers. Signed-off-by: Christoph Hellwig <hch@lst.de> Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
Diffstat (limited to 'fs/buffer.c')
-rw-r--r--fs/buffer.c52
1 files changed, 29 insertions, 23 deletions
diff --git a/fs/buffer.c b/fs/buffer.c
index 6c8ad977f3d..3e7dca279d1 100644
--- a/fs/buffer.c
+++ b/fs/buffer.c
@@ -770,11 +770,12 @@ static int fsync_buffers_list(spinlock_t *lock, struct list_head *list)
spin_unlock(lock);
/*
* Ensure any pending I/O completes so that
- * ll_rw_block() actually writes the current
- * contents - it is a noop if I/O is still in
- * flight on potentially older contents.
+ * write_dirty_buffer() actually writes the
+ * current contents - it is a noop if I/O is
+ * still in flight on potentially older
+ * contents.
*/
- ll_rw_block(SWRITE_SYNC_PLUG, 1, &bh);
+ write_dirty_buffer(bh, WRITE_SYNC_PLUG);
/*
* Kick off IO for the previous mapping. Note
@@ -2949,22 +2950,21 @@ EXPORT_SYMBOL(submit_bh);
/**
* ll_rw_block: low-level access to block devices (DEPRECATED)
- * @rw: whether to %READ or %WRITE or %SWRITE or maybe %READA (readahead)
+ * @rw: whether to %READ or %WRITE or maybe %READA (readahead)
* @nr: number of &struct buffer_heads in the array
* @bhs: array of pointers to &struct buffer_head
*
* ll_rw_block() takes an array of pointers to &struct buffer_heads, and
* requests an I/O operation on them, either a %READ or a %WRITE. The third
- * %SWRITE is like %WRITE only we make sure that the *current* data in buffers
- * are sent to disk. The fourth %READA option is described in the documentation
- * for generic_make_request() which ll_rw_block() calls.
+ * %READA option is described in the documentation for generic_make_request()
+ * which ll_rw_block() calls.
*
* This function drops any buffer that it cannot get a lock on (with the
- * BH_Lock state bit) unless SWRITE is required, any buffer that appears to be
- * clean when doing a write request, and any buffer that appears to be
- * up-to-date when doing read request. Further it marks as clean buffers that
- * are processed for writing (the buffer cache won't assume that they are
- * actually clean until the buffer gets unlocked).
+ * BH_Lock state bit), any buffer that appears to be clean when doing a write
+ * request, and any buffer that appears to be up-to-date when doing read
+ * request. Further it marks as clean buffers that are processed for
+ * writing (the buffer cache won't assume that they are actually clean
+ * until the buffer gets unlocked).
*
* ll_rw_block sets b_end_io to simple completion handler that marks
* the buffer up-to-date (if approriate), unlocks the buffer and wakes
@@ -2980,20 +2980,13 @@ void ll_rw_block(int rw, int nr, struct buffer_head *bhs[])
for (i = 0; i < nr; i++) {
struct buffer_head *bh = bhs[i];
- if (rw == SWRITE || rw == SWRITE_SYNC || rw == SWRITE_SYNC_PLUG)
- lock_buffer(bh);
- else if (!trylock_buffer(bh))
+ if (!trylock_buffer(bh))
continue;
-
- if (rw == WRITE || rw == SWRITE || rw == SWRITE_SYNC ||
- rw == SWRITE_SYNC_PLUG) {
+ if (rw == WRITE) {
if (test_clear_buffer_dirty(bh)) {
bh->b_end_io = end_buffer_write_sync;
get_bh(bh);
- if (rw == SWRITE_SYNC)
- submit_bh(WRITE_SYNC, bh);
- else
- submit_bh(WRITE, bh);
+ submit_bh(WRITE, bh);
continue;
}
} else {
@@ -3009,6 +3002,19 @@ void ll_rw_block(int rw, int nr, struct buffer_head *bhs[])
}
EXPORT_SYMBOL(ll_rw_block);
+void write_dirty_buffer(struct buffer_head *bh, int rw)
+{
+ lock_buffer(bh);
+ if (!test_clear_buffer_dirty(bh)) {
+ unlock_buffer(bh);
+ return;
+ }
+ bh->b_end_io = end_buffer_write_sync;
+ get_bh(bh);
+ submit_bh(rw, bh);
+}
+EXPORT_SYMBOL(write_dirty_buffer);
+
/*
* For a data-integrity writeout, we need to wait upon any in-progress I/O
* and then start new I/O and then wait upon it. The caller must have a ref on