nfs: take i_mutex during direct I/O reads
We'll need the i_mutex to prevent i_dio_count from incrementing while
truncate is waiting for it to reach zero, and protects against having
the pagecache repopulated after we flushed it.
Signed-off-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Trond Myklebust <trond.myklebust@primarydata.com>
diff --git a/fs/nfs/direct.c b/fs/nfs/direct.c
index cbfbd17..85e4e4b 100644
--- a/fs/nfs/direct.c
+++ b/fs/nfs/direct.c
@@ -500,16 +500,17 @@
if (!count)
goto out;
+ mutex_lock(&inode->i_mutex);
result = nfs_sync_mapping(mapping);
if (result)
- goto out;
+ goto out_unlock;
task_io_account_read(count);
result = -ENOMEM;
dreq = nfs_direct_req_alloc();
if (dreq == NULL)
- goto out;
+ goto out_unlock;
dreq->inode = inode;
dreq->bytes_left = iov_length(iov, nr_segs);
@@ -525,13 +526,22 @@
NFS_I(inode)->read_io += iov_length(iov, nr_segs);
result = nfs_direct_read_schedule_iovec(dreq, iov, nr_segs, pos, uio);
+
+ mutex_unlock(&inode->i_mutex);
+
if (!result) {
result = nfs_direct_wait(dreq);
if (result > 0)
iocb->ki_pos = pos + result;
}
+
+ nfs_direct_req_release(dreq);
+ return result;
+
out_release:
nfs_direct_req_release(dreq);
+out_unlock:
+ mutex_unlock(&inode->i_mutex);
out:
return result;
}