[Ocfs2-devel] [PATCH 3/4] ocfs2: Add splice read/write support
Tiger Yang
tiger.yang at oracle.com
Thu May 15 23:04:22 PDT 2008
commit 40bee44eaef91b6030037c8bb47f909181fb1edc in mainline
exported __splice_from_pipe(). This patch copied pipe_wait()
and __splice_from_pipe() from mainline to allow support for
splice io with enterprise kernels based on 2.6.18.
Signed-off-by: Tiger Yang <tiger.yang at oracle.com>
---
configure.in | 1 +
fs/ocfs2/Makefile | 1 +
fs/ocfs2/compat_splice.c | 129 ++++++++++++++++++++++++++++++++++++++++++
fs/ocfs2/file.c | 12 ++--
kapi-compat/include/splice.h | 16 +++++
5 files changed, 152 insertions(+), 7 deletions(-)
create mode 100644 fs/ocfs2/compat_splice.c
create mode 100644 kapi-compat/include/splice.h
diff --git a/configure.in b/configure.in
index 1a7b2b5..14a0316 100644
--- a/configure.in
+++ b/configure.in
@@ -268,6 +268,7 @@ NO_SPLICE_HEADER=
OCFS2_CHECK_KERNEL([struct splice_desc in splice.h], splice.h,
, NO_SPLICE_HEADER=yes, [^struct splice_desc ])
AC_SUBST(NO_SPLICE_HEADER)
+KAPI_COMPAT_HEADERS="$KAPI_COMPAT_HEADERS splice.h"
relatime_compat_header=""
OCFS2_CHECK_KERNEL([MNT_RELATIME in mount.h], mount.h,
diff --git a/fs/ocfs2/Makefile b/fs/ocfs2/Makefile
index dd1a8bc..f43da58 100644
--- a/fs/ocfs2/Makefile
+++ b/fs/ocfs2/Makefile
@@ -97,6 +97,7 @@ CFLAGS_file.o += -DNO_VECTORIZED_AIO
endif
ifdef NO_SPLICE_FROM_PIPE
+SOURCES += compat_splice.c
EXTRA_CFLAGS += -DNO_SPLICE_FROM_PIPE
endif
diff --git a/fs/ocfs2/compat_splice.c b/fs/ocfs2/compat_splice.c
new file mode 100644
index 0000000..31da274
--- /dev/null
+++ b/fs/ocfs2/compat_splice.c
@@ -0,0 +1,129 @@
+/*
+ * compat_splice.c
+ *
+ * This code has been copied from mainline linux kernel git commit
+ * 40bee44eaef91b6030037c8bb47f909181fb1edc to allow ocfs2 to build
+ * against older kernels. For license, refer to fs/splice.c in mainline
+ * linux kernel.
+ *
+ */
+
+void pipe_wait(struct pipe_inode_info *pipe)
+{
+ DEFINE_WAIT(wait);
+
+ /*
+ * Pipes are system-local resources, so sleeping on them
+ * is considered a noninteractive wait:
+ */
+ prepare_to_wait(&pipe->wait, &wait, TASK_INTERRUPTIBLE);
+ if (pipe->inode)
+ mutex_unlock(&pipe->inode->i_mutex);
+ schedule();
+ finish_wait(&pipe->wait, &wait);
+ if (pipe->inode)
+ mutex_lock(&pipe->inode->i_mutex);
+}
+
+/**
+ * __splice_from_pipe - splice data from a pipe to given actor
+ * @pipe: pipe to splice from
+ * @sd: information to @actor
+ * @actor: handler that splices the data
+ *
+ * Description:
+ * This function does little more than loop over the pipe and call
+ * @actor to do the actual moving of a single struct pipe_buffer to
+ * the desired destination. See pipe_to_file, pipe_to_sendpage, or
+ * pipe_to_user.
+ *
+ */
+ssize_t __splice_from_pipe(struct pipe_inode_info *pipe, struct splice_desc *sd,
+ splice_actor *actor)
+{
+ int ret, do_wakeup, err;
+
+ ret = 0;
+ do_wakeup = 0;
+
+ for (;;) {
+ if (pipe->nrbufs) {
+ struct pipe_buffer *buf = pipe->bufs + pipe->curbuf;
+ const struct pipe_buf_operations *ops = buf->ops;
+
+ sd->len = buf->len;
+ if (sd->len > sd->total_len)
+ sd->len = sd->total_len;
+
+ err = actor(pipe, buf, sd);
+ if (err <= 0) {
+ if (!ret && err != -ENODATA)
+ ret = err;
+
+ break;
+ }
+
+ ret += err;
+ buf->offset += err;
+ buf->len -= err;
+
+ sd->len -= err;
+ sd->pos += err;
+ sd->total_len -= err;
+ if (sd->len)
+ continue;
+
+ if (!buf->len) {
+ buf->ops = NULL;
+ ops->release(pipe, buf);
+ pipe->curbuf = (pipe->curbuf + 1) & (PIPE_BUFFERS - 1);
+ pipe->nrbufs--;
+ if (pipe->inode)
+ do_wakeup = 1;
+ }
+
+ if (!sd->total_len)
+ break;
+ }
+
+ if (pipe->nrbufs)
+ continue;
+ if (!pipe->writers)
+ break;
+ if (!pipe->waiting_writers) {
+ if (ret)
+ break;
+ }
+
+ if (sd->flags & SPLICE_F_NONBLOCK) {
+ if (!ret)
+ ret = -EAGAIN;
+ break;
+ }
+
+ if (signal_pending(current)) {
+ if (!ret)
+ ret = -ERESTARTSYS;
+ break;
+ }
+
+ if (do_wakeup) {
+ smp_mb();
+ if (waitqueue_active(&pipe->wait))
+ wake_up_interruptible_sync(&pipe->wait);
+ kill_fasync(&pipe->fasync_writers, SIGIO, POLL_OUT);
+ do_wakeup = 0;
+ }
+
+ pipe_wait(pipe);
+ }
+
+ if (do_wakeup) {
+ smp_mb();
+ if (waitqueue_active(&pipe->wait))
+ wake_up_interruptible(&pipe->wait);
+ kill_fasync(&pipe->fasync_writers, SIGIO, POLL_OUT);
+ }
+
+ return ret;
+}
diff --git a/fs/ocfs2/file.c b/fs/ocfs2/file.c
index af1a037..422c5f1 100644
--- a/fs/ocfs2/file.c
+++ b/fs/ocfs2/file.c
@@ -33,6 +33,8 @@
#include <linux/sched.h>
#ifndef NO_SPLICE_HEADER
#include <linux/splice.h>
+#else
+#include <linux/pipe_fs_i.h>
#endif
#include <linux/mount.h>
#include <linux/writeback.h>
@@ -2241,20 +2243,19 @@ out_sems:
return written ? written : ret;
}
-#ifndef NO_SPLICE_FROM_PIPE
static int ocfs2_splice_write_actor(struct pipe_inode_info *pipe,
struct pipe_buffer *buf,
struct splice_desc *sd)
{
int ret, count;
ssize_t copied = 0;
- struct file *file = sd->u.file;
+ struct file *file = sd_file(sd);
unsigned int offset;
struct page *page = NULL;
void *fsdata;
char *src, *dst;
- ret = buf->ops->confirm(pipe, buf);
+ ret = buf->ops->kapi_confirm(pipe, buf);
if (ret)
goto out;
@@ -2301,9 +2302,9 @@ static ssize_t __ocfs2_file_splice_write(struct pipe_inode_info *pipe,
.total_len = len,
.flags = flags,
.pos = *ppos,
- .u.file = out,
};
+ sd_file(&sd) = out;
ret = __splice_from_pipe(pipe, &sd, ocfs2_splice_write_actor);
if (ret > 0) {
*ppos += ret;
@@ -2390,7 +2391,6 @@ bail:
mlog_exit(ret);
return ret;
}
-#endif
static ssize_t __ocfs2_file_aio_read(struct kiocb *iocb,
const struct iovec *iov,
@@ -2550,10 +2550,8 @@ const struct file_operations ocfs2_fops = {
.compat_ioctl = ocfs2_compat_ioctl,
#endif
.flock = ocfs2_flock,
-#ifndef NO_SPLICE_FROM_PIPE
.splice_read = ocfs2_file_splice_read,
.splice_write = ocfs2_file_splice_write,
-#endif
#ifdef HAS_FOPS_SENDFILE
.sendfile = ocfs2_file_sendfile,
#endif
diff --git a/kapi-compat/include/splice.h b/kapi-compat/include/splice.h
new file mode 100644
index 0000000..f1fcdc0
--- /dev/null
+++ b/kapi-compat/include/splice.h
@@ -0,0 +1,16 @@
+#ifndef KAPI_SPLICE_H
+#define KAPI_SPLICE_H
+
+#ifdef NO_SPLICE_FROM_PIPE
+#include <linux/pipe_fs_i.h>
+ssize_t __splice_from_pipe(struct pipe_inode_info *pipe, struct splice_desc *sd,
+ splice_actor *actor);
+#endif
+
+#ifdef NO_SPLICE_HEADER
+# define sd_file(i) (i)->file
+#else
+# define sd_file(i) (i)->u.file
+#endif
+
+#endif
--
1.5.4.4
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