ceph: perform lazy reads when file mode and caps permit

If the file mode is marked as "lazy," perform cached/buffered reads when
the caps permit it.  Adjust the rdcache_gen and invalidation logic
accordingly so that we manage our cache based on the FILE_CACHE -or-
FILE_LAZYIO cap bits.

Signed-off-by: Sage Weil <sage@newdream.net>

1 files changed, 8 insertions, 4 deletions

diff --git a/fs/ceph/file.c b/fs/ceph/file.c
index 85c86ed5f4c0..2329244f427b 100644
--- a/fs/ceph/file.c
+++ b/fs/ceph/file.c
@@ -740,28 +740,32 @@ static ssize_t ceph_aio_read(struct kiocb *iocb, const struct iovec *iov,
                              unsigned long nr_segs, loff_t pos)
 {
         struct file *filp = iocb->ki_filp;
+        struct ceph_file_info *fi = filp->private_data;
         loff_t *ppos = &iocb->ki_pos;
         size_t len = iov->iov_len;
         struct inode *inode = filp->f_dentry->d_inode;
         struct ceph_inode_info *ci = ceph_inode(inode);
         void *base = iov->iov_base;
         ssize_t ret;
-        int got = 0;
+        int want, got = 0;
         int checkeof = 0, read = 0;
 
         dout("aio_read %p %llx.%llx %llu~%u trying to get caps on %p\n",
              inode, ceph_vinop(inode), pos, (unsigned)len, inode);
 again:
         __ceph_do_pending_vmtruncate(inode);
-        ret = ceph_get_caps(ci, CEPH_CAP_FILE_RD, CEPH_CAP_FILE_CACHE,
-                            &got, -1);
+        if (fi->fmode & CEPH_FILE_MODE_LAZY)
+                want = CEPH_CAP_FILE_CACHE | CEPH_CAP_FILE_LAZYIO;
+        else
+                want = CEPH_CAP_FILE_CACHE;
+        ret = ceph_get_caps(ci, CEPH_CAP_FILE_RD, want, &got, -1);
         if (ret < 0)
                 goto out;
         dout("aio_read %p %llx.%llx %llu~%u got cap refs on %s\n",
              inode, ceph_vinop(inode), pos, (unsigned)len,
              ceph_cap_string(got));
 
-        if ((got & CEPH_CAP_FILE_CACHE) == 0 ||
+        if ((got & (CEPH_CAP_FILE_CACHE|CEPH_CAP_FILE_LAZYIO)) == 0 ||
             (iocb->ki_filp->f_flags & O_DIRECT) ||
             (inode->i_sb->s_flags & MS_SYNCHRONOUS))
                 /* hmm, this isn't really async... */