fs/9p: Consolidate file operations and add readahead and writeback

We had 3 different sets of file operations across 2 different protocol
variants differentiated by cache which really only changed 3
functions.  But the real problem is that certain file modes, mount
options, and other factors weren't being considered when we
decided whether or not to use caches.

This consolidates all the operations and switches
to conditionals within a common set to decide whether or not
to do different aspects of caching.

Signed-off-by: Eric Van Hensbergen <ericvh@kernel.org>
Reviewed-by: Dominique Martinet <asmadeus@codewreck.org>

1 files changed, 20 insertions, 111 deletions

diff --git a/fs/9p/vfs_file.c b/fs/9p/vfs_file.c
index 44c15eb2b908..cd1f3f4079d7 100644
--- a/fs/9p/vfs_file.c
+++ b/fs/9p/vfs_file.c
@@ -29,7 +29,6 @@
 #include "fid.h"
 #include "cache.h"
 
-static const struct vm_operations_struct v9fs_file_vm_ops;
 static const struct vm_operations_struct v9fs_mmap_file_vm_ops;
 
 /**
@@ -74,7 +73,7 @@ int v9fs_file_open(struct inode *inode, struct file *file)
 	}
 
 	mutex_lock(&v9inode->v_mutex);
-	if ((v9ses->cache) && !v9inode->writeback_fid &&
+	if ((v9ses->cache >= CACHE_WRITEBACK) && !v9inode->writeback_fid &&
 	    ((file->f_flags & O_ACCMODE) != O_RDONLY)) {
 		/*
 		 * clone a fid and add it to writeback_fid
@@ -368,10 +367,15 @@ v9fs_file_read_iter(struct kiocb *iocb, struct iov_iter *to)
 {
 	struct p9_fid *fid = iocb->ki_filp->private_data;
 	int ret, err = 0;
+	struct inode *inode = file_inode(iocb->ki_filp);
+	struct v9fs_session_info *v9ses = v9fs_inode2v9ses(inode);
 
 	p9_debug(P9_DEBUG_VFS, "count %zu offset %lld\n",
 		 iov_iter_count(to), iocb->ki_pos);
 
+	if (v9ses->cache > CACHE_MMAP)
+		return generic_file_read_iter(iocb, to);
+
 	if (iocb->ki_filp->f_flags & O_NONBLOCK)
 		ret = p9_client_read_once(fid, iocb->ki_pos, to, &err);
 	else
@@ -396,6 +400,11 @@ v9fs_file_write_iter(struct kiocb *iocb, struct iov_iter *from)
 	ssize_t retval;
 	loff_t origin;
 	int err = 0;
+	struct inode *inode = file_inode(iocb->ki_filp);
+	struct v9fs_session_info *v9ses = v9fs_inode2v9ses(inode);
+
+	if (v9ses->cache >= CACHE_WRITEBACK)
+		return generic_file_write_iter(iocb, from);
 
 	retval = generic_write_checks(iocb, from);
 	if (retval <= 0)
@@ -478,25 +487,16 @@ static int
 v9fs_file_mmap(struct file *filp, struct vm_area_struct *vma)
 {
 	int retval;
-
-
-	retval = generic_file_mmap(filp, vma);
-	if (!retval)
-		vma->vm_ops = &v9fs_file_vm_ops;
-
-	return retval;
-}
-
-static int
-v9fs_mmap_file_mmap(struct file *filp, struct vm_area_struct *vma)
-{
-	int retval;
-	struct inode *inode;
-	struct v9fs_inode *v9inode;
+	struct inode *inode = file_inode(filp);
+	struct v9fs_inode *v9inode = V9FS_I(inode);
+	struct v9fs_session_info *v9ses = v9fs_inode2v9ses(inode);
 	struct p9_fid *fid;
 
-	inode = file_inode(filp);
-	v9inode = V9FS_I(inode);
+	if (v9ses->cache < CACHE_MMAP) {
+		invalidate_inode_pages2(filp->f_mapping);
+		return generic_file_readonly_mmap(filp, vma);
+	}
+
 	mutex_lock(&v9inode->v_mutex);
 	if (!v9inode->writeback_fid &&
 	    (vma->vm_flags & VM_SHARED) &&
@@ -564,35 +564,6 @@ out_unlock:
 	return VM_FAULT_NOPAGE;
 }
 
-/**
- * v9fs_mmap_file_read_iter - read from a file
- * @iocb: The operation parameters
- * @to: The buffer to read into
- *
- */
-static ssize_t
-v9fs_mmap_file_read_iter(struct kiocb *iocb, struct iov_iter *to)
-{
-	/* TODO: Check if there are dirty pages */
-	return v9fs_file_read_iter(iocb, to);
-}
-
-/**
- * v9fs_mmap_file_write_iter - write to a file
- * @iocb: The operation parameters
- * @from: The data to write
- *
- */
-static ssize_t
-v9fs_mmap_file_write_iter(struct kiocb *iocb, struct iov_iter *from)
-{
-	/*
-	 * TODO: invalidate mmaps on filp's inode between
-	 * offset and offset+count
-	 */
-	return v9fs_file_write_iter(iocb, from);
-}
-
 static void v9fs_mmap_vm_close(struct vm_area_struct *vma)
 {
 	struct inode *inode;
@@ -615,13 +586,6 @@ static void v9fs_mmap_vm_close(struct vm_area_struct *vma)
 	filemap_fdatawrite_wbc(inode->i_mapping, &wbc);
 }
 
-
-static const struct vm_operations_struct v9fs_file_vm_ops = {
-	.fault = filemap_fault,
-	.map_pages = filemap_map_pages,
-	.page_mkwrite = v9fs_vm_page_mkwrite,
-};
-
 static const struct vm_operations_struct v9fs_mmap_file_vm_ops = {
 	.close = v9fs_mmap_vm_close,
 	.fault = filemap_fault,
@@ -629,34 +593,6 @@ static const struct vm_operations_struct v9fs_mmap_file_vm_ops = {
 	.page_mkwrite = v9fs_vm_page_mkwrite,
 };
 
-
-const struct file_operations v9fs_cached_file_operations = {
-	.llseek = generic_file_llseek,
-	.read_iter = generic_file_read_iter,
-	.write_iter = generic_file_write_iter,
-	.open = v9fs_file_open,
-	.release = v9fs_dir_release,
-	.lock = v9fs_file_lock,
-	.mmap = v9fs_file_mmap,
-	.splice_read = generic_file_splice_read,
-	.splice_write = iter_file_splice_write,
-	.fsync = v9fs_file_fsync,
-};
-
-const struct file_operations v9fs_cached_file_operations_dotl = {
-	.llseek = generic_file_llseek,
-	.read_iter = generic_file_read_iter,
-	.write_iter = generic_file_write_iter,
-	.open = v9fs_file_open,
-	.release = v9fs_dir_release,
-	.lock = v9fs_file_lock_dotl,
-	.flock = v9fs_file_flock_dotl,
-	.mmap = v9fs_file_mmap,
-	.splice_read = generic_file_splice_read,
-	.splice_write = iter_file_splice_write,
-	.fsync = v9fs_file_fsync_dotl,
-};
-
 const struct file_operations v9fs_file_operations = {
 	.llseek = generic_file_llseek,
 	.read_iter = v9fs_file_read_iter,
@@ -678,34 +614,7 @@ const struct file_operations v9fs_file_operations_dotl = {
 	.release = v9fs_dir_release,
 	.lock = v9fs_file_lock_dotl,
 	.flock = v9fs_file_flock_dotl,
-	.mmap = generic_file_readonly_mmap,
-	.splice_read = generic_file_splice_read,
-	.splice_write = iter_file_splice_write,
-	.fsync = v9fs_file_fsync_dotl,
-};
-
-const struct file_operations v9fs_mmap_file_operations = {
-	.llseek = generic_file_llseek,
-	.read_iter = v9fs_mmap_file_read_iter,
-	.write_iter = v9fs_mmap_file_write_iter,
-	.open = v9fs_file_open,
-	.release = v9fs_dir_release,
-	.lock = v9fs_file_lock,
-	.mmap = v9fs_mmap_file_mmap,
-	.splice_read = generic_file_splice_read,
-	.splice_write = iter_file_splice_write,
-	.fsync = v9fs_file_fsync,
-};
-
-const struct file_operations v9fs_mmap_file_operations_dotl = {
-	.llseek = generic_file_llseek,
-	.read_iter = v9fs_mmap_file_read_iter,
-	.write_iter = v9fs_mmap_file_write_iter,
-	.open = v9fs_file_open,
-	.release = v9fs_dir_release,
-	.lock = v9fs_file_lock_dotl,
-	.flock = v9fs_file_flock_dotl,
-	.mmap = v9fs_mmap_file_mmap,
+	.mmap = v9fs_file_mmap,
 	.splice_read = generic_file_splice_read,
 	.splice_write = iter_file_splice_write,
 	.fsync = v9fs_file_fsync_dotl,