NFS: Reduce the number of unnecessary COMMIT calls

If the caller is doing a non-blocking flush, and there are still writebacks
pending on the wire, we can usually defer the COMMIT call until those
writes are done.

Also ensure that we honour the wbc->nonblocking flag.

Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>
This commit is contained in:
Trond Myklebust 2010-02-19 17:00:02 -08:00
parent ff778d02bf
commit 420e3646bb

View File

@ -1415,12 +1415,30 @@ static int nfs_commit_inode(struct inode *inode, int how)
static int nfs_commit_unstable_pages(struct inode *inode, struct writeback_control *wbc)
{
int ret;
struct nfs_inode *nfsi = NFS_I(inode);
int flags = FLUSH_SYNC;
int ret = 0;
ret = nfs_commit_inode(inode,
wbc->sync_mode == WB_SYNC_ALL ? FLUSH_SYNC : 0);
if (ret >= 0)
/* Don't commit yet if this is a non-blocking flush and there are
* lots of outstanding writes for this mapping.
*/
if (wbc->sync_mode == WB_SYNC_NONE &&
nfsi->ncommit <= (nfsi->npages >> 1))
goto out_mark_dirty;
if (wbc->nonblocking)
flags = 0;
ret = nfs_commit_inode(inode, flags);
if (ret >= 0) {
if (wbc->sync_mode == WB_SYNC_NONE) {
if (ret < wbc->nr_to_write)
wbc->nr_to_write -= ret;
else
wbc->nr_to_write = 0;
}
return 0;
}
out_mark_dirty:
__mark_inode_dirty(inode, I_DIRTY_DATASYNC);
return ret;
}