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Commit 328eaaba authored by Miklos Szeredi's avatar Miklos Szeredi Committed by Jens Axboe
Browse files

ocfs2: fix i_mutex locking in ocfs2_splice_to_file() 



Rearrange locking of i_mutex on destination and call to
ocfs2_rw_lock() so locks are only held while buffers are copied with
the pipe_to_file() actor, and not while waiting for more data on the
pipe.

Signed-off-by: default avatarMiklos Szeredi <mszeredi@suse.cz>
Signed-off-by: default avatarJens Axboe <jens.axboe@oracle.com>
parent eb443e5a

fs/ocfs2/file.c

+74 −20
Original line number Diff line number Diff line
@@ -1912,6 +1912,22 @@ static ssize_t ocfs2_file_aio_write(struct kiocb *iocb, 
	return written ? written : ret;

}



static int ocfs2_splice_to_file(struct pipe_inode_info *pipe,

				struct file *out,

				struct splice_desc *sd)

{

	int ret;



	ret = ocfs2_prepare_inode_for_write(out->f_path.dentry,	&sd->pos,

					    sd->total_len, 0, NULL);

	if (ret < 0) {

		mlog_errno(ret);

		return ret;

	}



	return splice_from_pipe_feed(pipe, sd, pipe_to_file);

}



static ssize_t ocfs2_file_splice_write(struct pipe_inode_info *pipe,

				       struct file *out,

				       loff_t *ppos,
@@ -1919,39 +1935,77 @@ static ssize_t ocfs2_file_splice_write(struct pipe_inode_info *pipe, 
				       unsigned int flags)

{

	int ret;

	struct inode *inode = out->f_path.dentry->d_inode;

	struct address_space *mapping = out->f_mapping;

	struct inode *inode = mapping->host;

	struct splice_desc sd = {

		.total_len = len,

		.flags = flags,

		.pos = *ppos,

		.u.file = out,

	};



	mlog_entry("(0x%p, 0x%p, %u, '%.*s')\n", out, pipe,

		   (unsigned int)len,

		   out->f_path.dentry->d_name.len,

		   out->f_path.dentry->d_name.name);



	mutex_lock_nested(&inode->i_mutex, I_MUTEX_PARENT);

	if (pipe->inode)

		mutex_lock_nested(&pipe->inode->i_mutex, I_MUTEX_PARENT);



	ret = ocfs2_rw_lock(inode, 1);

	if (ret < 0) {

		mlog_errno(ret);

		goto out;

	}

	splice_from_pipe_begin(&sd);

	do {

		ret = splice_from_pipe_next(pipe, &sd);

		if (ret <= 0)

			break;



	ret = ocfs2_prepare_inode_for_write(out->f_path.dentry, ppos, len, 0,

					    NULL);

	if (ret < 0) {

		mutex_lock_nested(&inode->i_mutex, I_MUTEX_CHILD);

		ret = ocfs2_rw_lock(inode, 1);

		if (ret < 0)

			mlog_errno(ret);

		goto out_unlock;

		else {

			ret = ocfs2_splice_to_file(pipe, out, &sd);

			ocfs2_rw_unlock(inode, 1);

		}

		mutex_unlock(&inode->i_mutex);

	} while (ret > 0);

	splice_from_pipe_end(pipe, &sd);



	if (pipe->inode)

		mutex_lock_nested(&pipe->inode->i_mutex, I_MUTEX_CHILD);

	ret = generic_file_splice_write_nolock(pipe, out, ppos, len, flags);

	if (pipe->inode)

		mutex_unlock(&pipe->inode->i_mutex);



out_unlock:

	if (sd.num_spliced)

		ret = sd.num_spliced;



	if (ret > 0) {

		unsigned long nr_pages;



		*ppos += ret;

		nr_pages = (ret + PAGE_CACHE_SIZE - 1) >> PAGE_CACHE_SHIFT;



		/*

		 * If file or inode is SYNC and we actually wrote some data,

		 * sync it.

		 */

		if (unlikely((out->f_flags & O_SYNC) || IS_SYNC(inode))) {

			int err;



			mutex_lock(&inode->i_mutex);

			err = ocfs2_rw_lock(inode, 1);

			if (err < 0) {

				mlog_errno(err);

			} else {

				err = generic_osync_inode(inode, mapping,

						  OSYNC_METADATA|OSYNC_DATA);

				ocfs2_rw_unlock(inode, 1);

out:

			}

			mutex_unlock(&inode->i_mutex);



			if (err)

				ret = err;

		}

		balance_dirty_pages_ratelimited_nr(mapping, nr_pages);

	}



	mlog_exit(ret);

	return ret;

}

fs/splice.c

+3 −2
Original line number Diff line number Diff line
@@ -555,7 +555,7 @@ static int pipe_to_sendpage(struct pipe_inode_info *pipe, 
 * SPLICE_F_MOVE isn't set, or we cannot move the page, we simply create

 * a new page in the output file page cache and fill/dirty that.

 */

static int pipe_to_file(struct pipe_inode_info *pipe, struct pipe_buffer *buf,

int pipe_to_file(struct pipe_inode_info *pipe, struct pipe_buffer *buf,

		 struct splice_desc *sd)

{

	struct file *file = sd->u.file;
@@ -600,6 +600,7 @@ static int pipe_to_file(struct pipe_inode_info *pipe, struct pipe_buffer *buf, 
out:

	return ret;

}

EXPORT_SYMBOL(pipe_to_file);



static void wakeup_pipe_writers(struct pipe_inode_info *pipe)

{

include/linux/splice.h

+2 −0
Original line number Diff line number Diff line
@@ -75,6 +75,8 @@ extern int splice_from_pipe_next(struct pipe_inode_info *, 
extern void splice_from_pipe_begin(struct splice_desc *);

extern void splice_from_pipe_end(struct pipe_inode_info *,

				 struct splice_desc *);

extern int pipe_to_file(struct pipe_inode_info *, struct pipe_buffer *,

			struct splice_desc *);



extern ssize_t splice_to_pipe(struct pipe_inode_info *,

			      struct splice_pipe_desc *);