Commit 7307de80 authored by Mark Fasheh's avatar Mark Fasheh
Browse files

ocfs2: shared writeable mmap 



Implement cluster consistent shared writeable mappings using the
->page_mkwrite() callback.

Signed-off-by: default avatarMark Fasheh <mark.fasheh@oracle.com>
parent 607d44aa

fs/ocfs2/aops.c

+41 −15
Original line number Diff line number Diff line
@@ -1034,7 +1034,8 @@ static int ocfs2_prepare_page_for_write(struct inode *inode, u64 *p_blkno, 
 */

static int ocfs2_grab_pages_for_write(struct address_space *mapping,

				      struct ocfs2_write_ctxt *wc,

				      u32 cpos, loff_t user_pos, int new)

				      u32 cpos, loff_t user_pos, int new,

				      struct page *mmap_page)

{

	int ret = 0, i;

	unsigned long start, target_index, index;
@@ -1058,12 +1059,37 @@ static int ocfs2_grab_pages_for_write(struct address_space *mapping, 
	for(i = 0; i < wc->w_num_pages; i++) {

		index = start + i;



		wc->w_pages[i] = find_or_create_page(mapping, index, GFP_NOFS);

		if (index == target_index && mmap_page) {

			/*

			 * ocfs2_pagemkwrite() is a little different

			 * and wants us to directly use the page

			 * passed in.

			 */

			lock_page(mmap_page);



			if (mmap_page->mapping != mapping) {

				unlock_page(mmap_page);

				/*

				 * Sanity check - the locking in

				 * ocfs2_pagemkwrite() should ensure

				 * that this code doesn't trigger.

				 */

				ret = -EINVAL;

				mlog_errno(ret);

				goto out;

			}



			page_cache_get(mmap_page);

			wc->w_pages[i] = mmap_page;

		} else {

			wc->w_pages[i] = find_or_create_page(mapping, index,

							     GFP_NOFS);

			if (!wc->w_pages[i]) {

				ret = -ENOMEM;

				mlog_errno(ret);

				goto out;

			}

		}



		if (index == target_index)

			wc->w_target_page = wc->w_pages[i];
@@ -1213,10 +1239,10 @@ static void ocfs2_set_target_boundaries(struct ocfs2_super *osb, 
	}

}



static int ocfs2_write_begin_nolock(struct address_space *mapping,

int ocfs2_write_begin_nolock(struct address_space *mapping,

			     loff_t pos, unsigned len, unsigned flags,

			     struct page **pagep, void **fsdata,

				    struct buffer_head *di_bh)

			     struct buffer_head *di_bh, struct page *mmap_page)

{

	int ret, i, credits = OCFS2_INODE_UPDATE_CREDITS;

	unsigned int num_clusters = 0, clusters_to_alloc = 0;
@@ -1318,7 +1344,7 @@ static int ocfs2_write_begin_nolock(struct address_space *mapping, 
	 * extent.

	 */

	ret = ocfs2_grab_pages_for_write(mapping, wc, wc->w_cpos, pos,

					 clusters_to_alloc);

					 clusters_to_alloc, mmap_page);

	if (ret) {

		mlog_errno(ret);

		goto out_commit;
@@ -1386,7 +1412,7 @@ int ocfs2_write_begin(struct file *file, struct address_space *mapping, 
	}



	ret = ocfs2_write_begin_nolock(mapping, pos, len, flags, pagep,

				       fsdata, di_bh);

				       fsdata, di_bh, NULL);

	if (ret) {

		mlog_errno(ret);

		goto out_fail_data;
@@ -1407,7 +1433,7 @@ int ocfs2_write_begin(struct file *file, struct address_space *mapping, 
	return ret;

}



static int ocfs2_write_end_nolock(struct address_space *mapping,

int ocfs2_write_end_nolock(struct address_space *mapping,

			   loff_t pos, unsigned len, unsigned copied,

			   struct page *page, void *fsdata)

{

fs/ocfs2/aops.h

+9 −0
Original line number Diff line number Diff line
@@ -50,6 +50,15 @@ int ocfs2_write_end(struct file *file, struct address_space *mapping, 
		    loff_t pos, unsigned len, unsigned copied,

		    struct page *page, void *fsdata);



int ocfs2_write_end_nolock(struct address_space *mapping,

			   loff_t pos, unsigned len, unsigned copied,

			   struct page *page, void *fsdata);



int ocfs2_write_begin_nolock(struct address_space *mapping,

			     loff_t pos, unsigned len, unsigned flags,

			     struct page **pagep, void **fsdata,

			     struct buffer_head *di_bh, struct page *mmap_page);



/* all ocfs2_dio_end_io()'s fault */

#define ocfs2_iocb_is_rw_locked(iocb) \

	test_bit(0, (unsigned long *)&iocb->private)

fs/ocfs2/file.c

+7 −0
Original line number Diff line number Diff line
@@ -1001,6 +1001,13 @@ int ocfs2_setattr(struct dentry *dentry, struct iattr *attr) 
		goto bail_unlock;

	}



	/*

	 * This will intentionally not wind up calling vmtruncate(),

	 * since all the work for a size change has been done above.

	 * Otherwise, we could get into problems with truncate as

	 * ip_alloc_sem is used there to protect against i_size

	 * changes.

	 */

	status = inode_setattr(inode, attr);

	if (status < 0) {

		mlog_errno(status);

fs/ocfs2/mmap.c

+143 −24
Original line number Diff line number Diff line
@@ -37,11 +37,29 @@ 


#include "ocfs2.h"



#include "aops.h"

#include "dlmglue.h"

#include "file.h"

#include "inode.h"

#include "mmap.h"



static inline int ocfs2_vm_op_block_sigs(sigset_t *blocked, sigset_t *oldset)

{

	/* The best way to deal with signals in the vm path is

	 * to block them upfront, rather than allowing the

	 * locking paths to return -ERESTARTSYS. */

	sigfillset(blocked);



	/* We should technically never get a bad return value

	 * from sigprocmask */

	return sigprocmask(SIG_BLOCK, blocked, oldset);

}



static inline int ocfs2_vm_op_unblock_sigs(sigset_t *oldset)

{

	return sigprocmask(SIG_SETMASK, oldset, NULL);

}



static struct page *ocfs2_nopage(struct vm_area_struct * area,

				 unsigned long address,

				 int *type)
@@ -53,14 +71,7 @@ static struct page *ocfs2_nopage(struct vm_area_struct * area, 
	mlog_entry("(area=%p, address=%lu, type=%p)\n", area, address,

		   type);



	/* The best way to deal with signals in this path is

	 * to block them upfront, rather than allowing the

	 * locking paths to return -ERESTARTSYS. */

	sigfillset(&blocked);



	/* We should technically never get a bad ret return

	 * from sigprocmask */

	ret = sigprocmask(SIG_BLOCK, &blocked, &oldset);

	ret = ocfs2_vm_op_block_sigs(&blocked, &oldset);

	if (ret < 0) {

		mlog_errno(ret);

		goto out;
@@ -68,7 +79,7 @@ static struct page *ocfs2_nopage(struct vm_area_struct * area, 


	page = filemap_nopage(area, address, type);



	ret = sigprocmask(SIG_SETMASK, &oldset, NULL);

	ret = ocfs2_vm_op_unblock_sigs(&oldset);

	if (ret < 0)

		mlog_errno(ret);

out:
@@ -76,27 +87,135 @@ static struct page *ocfs2_nopage(struct vm_area_struct * area, 
	return page;

}



static int __ocfs2_page_mkwrite(struct inode *inode, struct buffer_head *di_bh,

				struct page *page)

{

	int ret;

	struct address_space *mapping = inode->i_mapping;

	loff_t pos = page->index << PAGE_CACHE_SHIFT;

	unsigned int len = PAGE_CACHE_SIZE;

	pgoff_t last_index;

	struct page *locked_page = NULL;

	void *fsdata;

	loff_t size = i_size_read(inode);



	/*

	 * Another node might have truncated while we were waiting on

	 * cluster locks.

	 */

	last_index = size >> PAGE_CACHE_SHIFT;

	if (page->index > last_index) {

		ret = -EINVAL;

		goto out;

	}



	/*

	 * The i_size check above doesn't catch the case where nodes

	 * truncated and then re-extended the file. We'll re-check the

	 * page mapping after taking the page lock inside of

	 * ocfs2_write_begin_nolock().

	 */

	if (!PageUptodate(page) || page->mapping != inode->i_mapping) {

		ret = -EINVAL;

		goto out;

	}



	/*

	 * Call ocfs2_write_begin() and ocfs2_write_end() to take

	 * advantage of the allocation code there. We pass a write

	 * length of the whole page (chopped to i_size) to make sure

	 * the whole thing is allocated.

	 *

	 * Since we know the page is up to date, we don't have to

	 * worry about ocfs2_write_begin() skipping some buffer reads

	 * because the "write" would invalidate their data.

	 */

	if (page->index == last_index)

		len = size & ~PAGE_CACHE_MASK;



	ret = ocfs2_write_begin_nolock(mapping, pos, len, 0, &locked_page,

				       &fsdata, di_bh, page);

	if (ret) {

		if (ret != -ENOSPC)

			mlog_errno(ret);

		goto out;

	}



	ret = ocfs2_write_end_nolock(mapping, pos, len, len, locked_page,

				     fsdata);

	if (ret < 0) {

		mlog_errno(ret);

		goto out;

	}

	BUG_ON(ret != len);

	ret = 0;

out:

	return ret;

}



static int ocfs2_page_mkwrite(struct vm_area_struct *vma, struct page *page)

{

	struct inode *inode = vma->vm_file->f_path.dentry->d_inode;

	struct buffer_head *di_bh = NULL;

	sigset_t blocked, oldset;

	int ret, ret2;



	ret = ocfs2_vm_op_block_sigs(&blocked, &oldset);

	if (ret < 0) {

		mlog_errno(ret);

		return ret;

	}



	/*

	 * The cluster locks taken will block a truncate from another

	 * node. Taking the data lock will also ensure that we don't

	 * attempt page truncation as part of a downconvert.

	 */

	ret = ocfs2_meta_lock(inode, &di_bh, 1);

	if (ret < 0) {

		mlog_errno(ret);

		goto out;

	}



	/*

	 * The alloc sem should be enough to serialize with

	 * ocfs2_truncate_file() changing i_size as well as any thread

	 * modifying the inode btree.

	 */

	down_write(&OCFS2_I(inode)->ip_alloc_sem);



	ret = ocfs2_data_lock(inode, 1);

	if (ret < 0) {

		mlog_errno(ret);

		goto out_meta_unlock;

	}



	ret = __ocfs2_page_mkwrite(inode, di_bh, page);



	ocfs2_data_unlock(inode, 1);



out_meta_unlock:

	up_write(&OCFS2_I(inode)->ip_alloc_sem);



	brelse(di_bh);

	ocfs2_meta_unlock(inode, 1);



out:

	ret2 = ocfs2_vm_op_unblock_sigs(&oldset);

	if (ret2 < 0)

		mlog_errno(ret2);



	return ret;

}



static struct vm_operations_struct ocfs2_file_vm_ops = {

	.nopage		= ocfs2_nopage,

	.page_mkwrite	= ocfs2_page_mkwrite,

};



int ocfs2_mmap(struct file *file, struct vm_area_struct *vma)

{

	int ret = 0, lock_level = 0;

	struct ocfs2_super *osb = OCFS2_SB(file->f_dentry->d_inode->i_sb);



	/*

	 * Only support shared writeable mmap for local mounts which

	 * don't know about holes.

	 */

	if ((!ocfs2_mount_local(osb) || ocfs2_sparse_alloc(osb)) &&

	    ((vma->vm_flags & VM_SHARED) || (vma->vm_flags & VM_MAYSHARE)) &&

	    ((vma->vm_flags & VM_WRITE) || (vma->vm_flags & VM_MAYWRITE))) {

		mlog(0, "disallow shared writable mmaps %lx\n", vma->vm_flags);

		/* This is -EINVAL because generic_file_readonly_mmap

		 * returns it in a similar situation. */

		return -EINVAL;

	}



	ret = ocfs2_meta_lock_atime(file->f_dentry->d_inode,

				    file->f_vfsmnt, &lock_level);