afs: Implement shared-writeable mmap (1cf7a151) · Commits · e / devices / android_kernel_oneplus_sm7250

fs/afs/file.c

+21 −1

Original line number	Diff line number	Diff line
		@@ -19,6 +19,7 @@
		#include <linux/task_io_accounting_ops.h>
		#include "internal.h"

		static int afs_file_mmap(struct file file, struct vm_area_struct vma);
		static int afs_readpage(struct file file, struct page page);
		static void afs_invalidatepage(struct page *page, unsigned int offset,
		unsigned int length);
		@@ -34,7 +35,7 @@ const struct file_operations afs_file_operations = {
		.llseek = generic_file_llseek,
		.read_iter = generic_file_read_iter,
		.write_iter = afs_file_write,
		.mmap = generic_file_readonly_mmap,
		.mmap = afs_file_mmap,
		.splice_read = generic_file_splice_read,
		.fsync = afs_fsync,
		.lock = afs_lock,
		@@ -61,6 +62,12 @@ const struct address_space_operations afs_fs_aops = {
		.writepages = afs_writepages,
		};

		static const struct vm_operations_struct afs_vm_ops = {
		.fault = filemap_fault,
		.map_pages = filemap_map_pages,
		.page_mkwrite = afs_page_mkwrite,
		};

		/*
		* Discard a pin on a writeback key.
		*/
		@@ -629,3 +636,16 @@ static int afs_releasepage(struct page *page, gfp_t gfp_flags)
		_leave(" = T");
		return 1;
		}

		/*
		* Handle setting up a memory mapping on an AFS file.
		*/
		static int afs_file_mmap(struct file file, struct vm_area_struct vma)
		{
		int ret;

		ret = generic_file_mmap(file, vma);
		if (ret == 0)
		vma->vm_ops = &afs_vm_ops;
		return ret;
		}

fs/afs/internal.h

+1 −0

Original line number	Diff line number	Diff line
		@@ -886,6 +886,7 @@ extern void afs_pages_written_back(struct afs_vnode , struct afs_call );
		extern ssize_t afs_file_write(struct kiocb , struct iov_iter );
		extern int afs_flush(struct file *, fl_owner_t);
		extern int afs_fsync(struct file *, loff_t, loff_t, int);
		extern int afs_page_mkwrite(struct vm_fault *);
		extern void afs_prune_wb_keys(struct afs_vnode *);
		extern int afs_launder_page(struct page *);

fs/afs/write.c

+32 −8

Original line number	Diff line number	Diff line
		@@ -749,21 +749,45 @@ int afs_flush(struct file *file, fl_owner_t id)
		* notification that a previously read-only page is about to become writable
		* - if it returns an error, the caller will deliver a bus error signal
		*/
		int afs_page_mkwrite(struct vm_area_struct vma, struct page page)
		int afs_page_mkwrite(struct vm_fault *vmf)
		{
		struct afs_vnode *vnode = AFS_FS_I(vma->vm_file->f_mapping->host);
		struct file *file = vmf->vma->vm_file;
		struct inode *inode = file_inode(file);
		struct afs_vnode *vnode = AFS_FS_I(inode);
		unsigned long priv;

		_enter("{{%x:%u}},{%lx}",
		vnode->fid.vid, vnode->fid.vnode, page->index);
		vnode->fid.vid, vnode->fid.vnode, vmf->page->index);

		/* wait for the page to be written to the cache before we allow it to
		* be modified */
		sb_start_pagefault(inode->i_sb);

		/* Wait for the page to be written to the cache before we allow it to
		* be modified. We then assume the entire page will need writing back.
		*/
		#ifdef CONFIG_AFS_FSCACHE
		fscache_wait_on_page_write(vnode->cache, page);
		fscache_wait_on_page_write(vnode->cache, vmf->page);
		#endif

		_leave(" = 0");
		return 0;
		if (PageWriteback(vmf->page) &&
		wait_on_page_bit_killable(vmf->page, PG_writeback) < 0)
		return VM_FAULT_RETRY;

		if (lock_page_killable(vmf->page) < 0)
		return VM_FAULT_RETRY;

		/* We mustn't change page->private until writeback is complete as that
		* details the portion of the page we need to write back and we might
		* need to redirty the page if there's a problem.
		*/
		wait_on_page_writeback(vmf->page);

		priv = (unsigned long)PAGE_SIZE << AFS_PRIV_SHIFT; /* To */
		priv \|= 0; /* From */
		SetPagePrivate(vmf->page);
		set_page_private(vmf->page, priv);

		sb_end_pagefault(inode->i_sb);
		return VM_FAULT_LOCKED;
		}

		/*