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splice: fix i_mutex locking in generic_splice_write() 

Rearrange locking of i_mutex on destination so it's 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: Miklos Szeredi <mszeredi@suse.cz>
Signed-off-by: Jens Axboe <jens.axboe@oracle.com>
This commit is contained in:
Miklos Szeredi 2009-04-14 19:48:38 +02:00 committed by Jens Axboe
parent 2933970b96
commit eb443e5a25
1 changed files with 23 additions and 11 deletions
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34
fs/splice.c
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@ -895,17 +895,29 @@ generic_file_splice_write(struct pipe_inode_info *pipe, struct file *out,
};
ssize_t ret;
WARN_ON(S_ISFIFO(inode->i_mode));
mutex_lock_nested(&inode->i_mutex, I_MUTEX_PARENT);
ret = file_remove_suid(out);
if (likely(!ret)) {
if (pipe->inode)
mutex_lock_nested(&pipe->inode->i_mutex, I_MUTEX_CHILD);
ret = __splice_from_pipe(pipe, &sd, pipe_to_file);
if (pipe->inode)
mutex_unlock(&pipe->inode->i_mutex);
}
mutex_unlock(&inode->i_mutex);
if (pipe->inode)
mutex_lock_nested(&pipe->inode->i_mutex, I_MUTEX_PARENT);
splice_from_pipe_begin(&sd);
do {
ret = splice_from_pipe_next(pipe, &sd);
if (ret <= 0)
break;
mutex_lock_nested(&inode->i_mutex, I_MUTEX_CHILD);
ret = file_remove_suid(out);
if (!ret)
ret = splice_from_pipe_feed(pipe, &sd, pipe_to_file);
mutex_unlock(&inode->i_mutex);
} while (ret > 0);
splice_from_pipe_end(pipe, &sd);
if (pipe->inode)
mutex_unlock(&pipe->inode->i_mutex);
if (sd.num_spliced)
ret = sd.num_spliced;
if (ret > 0) {
unsigned long nr_pages;