ocfs2: shared writeable mmap (7307de80) · Commits · e / devices / android_kernel_teracube_emerald

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);