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Date: Thu, 17 Feb 2011 23:31:53 +0530
From: "Aneesh Kumar K.V" <aneesh.kumar@...ux.vnet.ibm.com>
To: v9fs-developer@...ts.sourceforge.net
Cc: linux-fsdevel@...r.kernel.org, linux-kernel@...r.kernel.org,
"Aneesh Kumar K.V" <aneesh.kumar@...ux.vnet.ibm.com>
Subject: [PATCH 02/14] fs/9p: Add direct IO support in cached mode
Signed-off-by: Aneesh Kumar K.V <aneesh.kumar@...ux.vnet.ibm.com>
---
fs/9p/vfs_file.c | 118 ++++++++++++++++++++++++++++++++++++++++++++++++++++--
1 files changed, 114 insertions(+), 4 deletions(-)
diff --git a/fs/9p/vfs_file.c b/fs/9p/vfs_file.c
index a56a33b..5de87e2 100644
--- a/fs/9p/vfs_file.c
+++ b/fs/9p/vfs_file.c
@@ -590,15 +590,125 @@ out_unlock:
return VM_FAULT_NOPAGE;
}
+static ssize_t
+v9fs_direct_read(struct file *filp, char __user *udata, size_t count,
+ loff_t *offsetp)
+{
+ loff_t size, offset;
+ struct inode *inode;
+ struct address_space *mapping;
+
+ offset = *offsetp;
+ mapping = filp->f_mapping;
+ inode = mapping->host;
+ if (!count)
+ return 0;
+ size = i_size_read(inode);
+ if (offset < size)
+ filemap_write_and_wait_range(mapping, offset,
+ offset + count - 1);
+
+ return v9fs_file_read(filp, udata, count, offsetp);
+}
+
+/**
+ * v9fs_cached_file_read - read from a file
+ * @filp: file pointer to read
+ * @udata: user data buffer to read data into
+ * @count: size of buffer
+ * @offset: offset at which to read data
+ *
+ */
+static ssize_t
+v9fs_cached_file_read(struct file *filp, char __user *data, size_t count,
+ loff_t *offset)
+{
+ if (filp->f_flags & O_DIRECT)
+ return v9fs_direct_read(filp, data, count, offset);
+ return do_sync_read(filp, data, count, offset);
+}
+
+static ssize_t
+v9fs_direct_write(struct file *filp, const char __user * data,
+ size_t count, loff_t *offsetp)
+{
+ loff_t offset;
+ ssize_t retval;
+ struct inode *inode;
+ struct address_space *mapping;
+
+ offset = *offsetp;
+ mapping = filp->f_mapping;
+ inode = mapping->host;
+ if (!count)
+ return 0;
+
+ mutex_lock(&inode->i_mutex);
+ retval = filemap_write_and_wait_range(mapping, offset,
+ offset + count - 1);
+ if (retval)
+ goto err_out;
+ /*
+ * After a write we want buffered reads to be sure to go to disk to get
+ * the new data. We invalidate clean cached page from the region we're
+ * about to write. We do this *before* the write so that if we fail
+ * here we fall back to buffered write
+ */
+ if (mapping->nrpages) {
+ pgoff_t pg_start = offset >> PAGE_CACHE_SHIFT;
+ pgoff_t pg_end = (offset + count - 1) >> PAGE_CACHE_SHIFT;
+
+ retval = invalidate_inode_pages2_range(mapping,
+ pg_start, pg_end);
+ /*
+ * If a page can not be invalidated, return 0 to fall back
+ * to buffered write.
+ */
+ if (retval) {
+ if (retval == -EBUSY) {
+ retval = 0;
+ goto buff_write;
+ }
+ goto err_out;
+ }
+ }
+ retval = v9fs_file_write(filp, data, count, offsetp);
+err_out:
+ mutex_unlock(&inode->i_mutex);
+ return retval;
+
+buff_write:
+ return do_sync_write(filp, data, count, offsetp);
+}
+
+/**
+ * v9fs_cached_file_write - write to a file
+ * @filp: file pointer to write
+ * @data: data buffer to write data from
+ * @count: size of buffer
+ * @offset: offset at which to write data
+ *
+ */
+static ssize_t
+v9fs_cached_file_write(struct file *filp, const char __user * data,
+ size_t count, loff_t *offset)
+{
+
+ if (filp->f_flags & O_DIRECT)
+ return v9fs_direct_write(filp, data, count, offset);
+ return do_sync_write(filp, data, count, offset);
+}
+
static const struct vm_operations_struct v9fs_file_vm_ops = {
.fault = filemap_fault,
.page_mkwrite = v9fs_vm_page_mkwrite,
};
+
const struct file_operations v9fs_cached_file_operations = {
.llseek = generic_file_llseek,
- .read = do_sync_read,
- .write = do_sync_write,
+ .read = v9fs_cached_file_read,
+ .write = v9fs_cached_file_write,
.aio_read = generic_file_aio_read,
.aio_write = generic_file_aio_write,
.open = v9fs_file_open,
@@ -610,8 +720,8 @@ const struct file_operations v9fs_cached_file_operations = {
const struct file_operations v9fs_cached_file_operations_dotl = {
.llseek = generic_file_llseek,
- .read = do_sync_read,
- .write = do_sync_write,
+ .read = v9fs_cached_file_read,
+ .write = v9fs_cached_file_write,
.aio_read = generic_file_aio_read,
.aio_write = generic_file_aio_write,
.open = v9fs_file_open,
--
1.7.1
--
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