diff options
Diffstat (limited to 'fs/splice.c')
| -rw-r--r-- | fs/splice.c | 150 |
1 files changed, 112 insertions, 38 deletions
diff --git a/fs/splice.c b/fs/splice.c index a567010b62a..2fca6ebf4cc 100644 --- a/fs/splice.c +++ b/fs/splice.c @@ -42,7 +42,7 @@ struct splice_pipe_desc { struct partial_page *partial; /* pages[] may not be contig */ int nr_pages; /* number of pages in map */ unsigned int flags; /* splice flags */ - struct pipe_buf_operations *ops;/* ops associated with output pipe */ + const struct pipe_buf_operations *ops;/* ops associated with output pipe */ }; /* @@ -74,7 +74,7 @@ static int page_cache_pipe_buf_steal(struct pipe_inode_info *pipe, wait_on_page_writeback(page); if (PagePrivate(page)) - try_to_release_page(page, mapping_gfp_mask(mapping)); + try_to_release_page(page, GFP_KERNEL); /* * If we succeeded in removing the mapping, set LRU flag @@ -139,7 +139,7 @@ error: return err; } -static struct pipe_buf_operations page_cache_pipe_buf_ops = { +static const struct pipe_buf_operations page_cache_pipe_buf_ops = { .can_merge = 0, .map = generic_pipe_buf_map, .unmap = generic_pipe_buf_unmap, @@ -159,7 +159,7 @@ static int user_page_pipe_buf_steal(struct pipe_inode_info *pipe, return generic_pipe_buf_steal(pipe, buf); } -static struct pipe_buf_operations user_page_pipe_buf_ops = { +static const struct pipe_buf_operations user_page_pipe_buf_ops = { .can_merge = 0, .map = generic_pipe_buf_map, .unmap = generic_pipe_buf_unmap, @@ -333,7 +333,7 @@ __generic_file_splice_read(struct file *in, loff_t *ppos, break; error = add_to_page_cache_lru(page, mapping, index, - mapping_gfp_mask(mapping)); + GFP_KERNEL); if (unlikely(error)) { page_cache_release(page); if (error == -EEXIST) @@ -557,7 +557,6 @@ static int pipe_to_file(struct pipe_inode_info *pipe, struct pipe_buffer *buf, { struct file *file = sd->file; struct address_space *mapping = file->f_mapping; - gfp_t gfp_mask = mapping_gfp_mask(mapping); unsigned int offset, this_len; struct page *page; pgoff_t index; @@ -591,7 +590,7 @@ static int pipe_to_file(struct pipe_inode_info *pipe, struct pipe_buffer *buf, goto find_page; page = buf->page; - if (add_to_page_cache(page, mapping, index, gfp_mask)) { + if (add_to_page_cache(page, mapping, index, GFP_KERNEL)) { unlock_page(page); goto find_page; } @@ -613,7 +612,7 @@ find_page: * This will also lock the page */ ret = add_to_page_cache_lru(page, mapping, index, - gfp_mask); + GFP_KERNEL); if (unlikely(ret)) goto out; } @@ -707,9 +706,9 @@ out_ret: * key here is the 'actor' worker passed in that actually moves the data * to the wanted destination. See pipe_to_file/pipe_to_sendpage above. */ -ssize_t splice_from_pipe(struct pipe_inode_info *pipe, struct file *out, - loff_t *ppos, size_t len, unsigned int flags, - splice_actor *actor) +static ssize_t __splice_from_pipe(struct pipe_inode_info *pipe, + struct file *out, loff_t *ppos, size_t len, + unsigned int flags, splice_actor *actor) { int ret, do_wakeup, err; struct splice_desc sd; @@ -722,13 +721,10 @@ ssize_t splice_from_pipe(struct pipe_inode_info *pipe, struct file *out, sd.file = out; sd.pos = *ppos; - if (pipe->inode) - mutex_lock(&pipe->inode->i_mutex); - for (;;) { if (pipe->nrbufs) { struct pipe_buffer *buf = pipe->bufs + pipe->curbuf; - struct pipe_buf_operations *ops = buf->ops; + const struct pipe_buf_operations *ops = buf->ops; sd.len = buf->len; if (sd.len > sd.total_len) @@ -797,9 +793,6 @@ ssize_t splice_from_pipe(struct pipe_inode_info *pipe, struct file *out, pipe_wait(pipe); } - if (pipe->inode) - mutex_unlock(&pipe->inode->i_mutex); - if (do_wakeup) { smp_mb(); if (waitqueue_active(&pipe->wait)) @@ -810,6 +803,73 @@ ssize_t splice_from_pipe(struct pipe_inode_info *pipe, struct file *out, return ret; } +ssize_t splice_from_pipe(struct pipe_inode_info *pipe, struct file *out, + loff_t *ppos, size_t len, unsigned int flags, + splice_actor *actor) +{ + ssize_t ret; + struct inode *inode = out->f_mapping->host; + + /* + * The actor worker might be calling ->prepare_write and + * ->commit_write. Most of the time, these expect i_mutex to + * be held. Since this may result in an ABBA deadlock with + * pipe->inode, we have to order lock acquiry here. + */ + inode_double_lock(inode, pipe->inode); + ret = __splice_from_pipe(pipe, out, ppos, len, flags, actor); + inode_double_unlock(inode, pipe->inode); + + return ret; +} + +/** + * generic_file_splice_write_nolock - generic_file_splice_write without mutexes + * @pipe: pipe info + * @out: file to write to + * @len: number of bytes to splice + * @flags: splice modifier flags + * + * Will either move or copy pages (determined by @flags options) from + * the given pipe inode to the given file. The caller is responsible + * for acquiring i_mutex on both inodes. + * + */ +ssize_t +generic_file_splice_write_nolock(struct pipe_inode_info *pipe, struct file *out, + loff_t *ppos, size_t len, unsigned int flags) +{ + struct address_space *mapping = out->f_mapping; + struct inode *inode = mapping->host; + ssize_t ret; + int err; + + err = remove_suid(out->f_path.dentry); + if (unlikely(err)) + return err; + + ret = __splice_from_pipe(pipe, out, ppos, len, flags, pipe_to_file); + if (ret > 0) { + *ppos += ret; + + /* + * If file or inode is SYNC and we actually wrote some data, + * sync it. + */ + if (unlikely((out->f_flags & O_SYNC) || IS_SYNC(inode))) { + err = generic_osync_inode(inode, mapping, + OSYNC_METADATA|OSYNC_DATA); + + if (err) + ret = err; + } + } + + return ret; +} + +EXPORT_SYMBOL(generic_file_splice_write_nolock); + /** * generic_file_splice_write - splice data from a pipe to a file * @pipe: pipe info @@ -826,12 +886,21 @@ generic_file_splice_write(struct pipe_inode_info *pipe, struct file *out, loff_t *ppos, size_t len, unsigned int flags) { struct address_space *mapping = out->f_mapping; + struct inode *inode = mapping->host; ssize_t ret; + int err; + + err = should_remove_suid(out->f_path.dentry); + if (unlikely(err)) { + mutex_lock(&inode->i_mutex); + err = __remove_suid(out->f_path.dentry, err); + mutex_unlock(&inode->i_mutex); + if (err) + return err; + } ret = splice_from_pipe(pipe, out, ppos, len, flags, pipe_to_file); if (ret > 0) { - struct inode *inode = mapping->host; - *ppos += ret; /* @@ -839,8 +908,6 @@ generic_file_splice_write(struct pipe_inode_info *pipe, struct file *out, * sync it. */ if (unlikely((out->f_flags & O_SYNC) || IS_SYNC(inode))) { - int err; - mutex_lock(&inode->i_mutex); err = generic_osync_inode(inode, mapping, OSYNC_METADATA|OSYNC_DATA); @@ -941,7 +1008,7 @@ long do_splice_direct(struct file *in, loff_t *ppos, struct file *out, * randomly drop data for eg socket -> socket splicing. Use the * piped splicing for that! */ - i_mode = in->f_dentry->d_inode->i_mode; + i_mode = in->f_path.dentry->d_inode->i_mode; if (unlikely(!S_ISREG(i_mode) && !S_ISBLK(i_mode))) return -EINVAL; @@ -1042,6 +1109,19 @@ out_release: EXPORT_SYMBOL(do_splice_direct); /* + * After the inode slimming patch, i_pipe/i_bdev/i_cdev share the same + * location, so checking ->i_pipe is not enough to verify that this is a + * pipe. + */ +static inline struct pipe_inode_info *pipe_info(struct inode *inode) +{ + if (S_ISFIFO(inode->i_mode)) + return inode->i_pipe; + + return NULL; +} + +/* * Determine where to splice to/from. */ static long do_splice(struct file *in, loff_t __user *off_in, @@ -1052,7 +1132,7 @@ static long do_splice(struct file *in, loff_t __user *off_in, loff_t offset, *off; long ret; - pipe = in->f_dentry->d_inode->i_pipe; + pipe = pipe_info(in->f_path.dentry->d_inode); if (pipe) { if (off_in) return -ESPIPE; @@ -1073,7 +1153,7 @@ static long do_splice(struct file *in, loff_t __user *off_in, return ret; } - pipe = out->f_dentry->d_inode->i_pipe; + pipe = pipe_info(out->f_path.dentry->d_inode); if (pipe) { if (off_out) return -ESPIPE; @@ -1231,7 +1311,7 @@ static int get_iovec_page_array(const struct iovec __user *iov, static long do_vmsplice(struct file *file, const struct iovec __user *iov, unsigned long nr_segs, unsigned int flags) { - struct pipe_inode_info *pipe = file->f_dentry->d_inode->i_pipe; + struct pipe_inode_info *pipe; struct page *pages[PIPE_BUFFERS]; struct partial_page partial[PIPE_BUFFERS]; struct splice_pipe_desc spd = { @@ -1241,7 +1321,8 @@ static long do_vmsplice(struct file *file, const struct iovec __user *iov, .ops = &user_page_pipe_buf_ops, }; - if (unlikely(!pipe)) + pipe = pipe_info(file->f_path.dentry->d_inode); + if (!pipe) return -EBADF; if (unlikely(nr_segs > UIO_MAXIOV)) return -EINVAL; @@ -1400,13 +1481,7 @@ static int link_pipe(struct pipe_inode_info *ipipe, * grabbing by inode address. Otherwise two different processes * could deadlock (one doing tee from A -> B, the other from B -> A). */ - if (ipipe->inode < opipe->inode) { - mutex_lock_nested(&ipipe->inode->i_mutex, I_MUTEX_PARENT); - mutex_lock_nested(&opipe->inode->i_mutex, I_MUTEX_CHILD); - } else { - mutex_lock_nested(&opipe->inode->i_mutex, I_MUTEX_PARENT); - mutex_lock_nested(&ipipe->inode->i_mutex, I_MUTEX_CHILD); - } + inode_double_lock(ipipe->inode, opipe->inode); do { if (!opipe->readers) { @@ -1450,8 +1525,7 @@ static int link_pipe(struct pipe_inode_info *ipipe, i++; } while (len); - mutex_unlock(&ipipe->inode->i_mutex); - mutex_unlock(&opipe->inode->i_mutex); + inode_double_unlock(ipipe->inode, opipe->inode); /* * If we put data in the output pipe, wakeup any potential readers. @@ -1475,8 +1549,8 @@ static int link_pipe(struct pipe_inode_info *ipipe, static long do_tee(struct file *in, struct file *out, size_t len, unsigned int flags) { - struct pipe_inode_info *ipipe = in->f_dentry->d_inode->i_pipe; - struct pipe_inode_info *opipe = out->f_dentry->d_inode->i_pipe; + struct pipe_inode_info *ipipe = pipe_info(in->f_path.dentry->d_inode); + struct pipe_inode_info *opipe = pipe_info(out->f_path.dentry->d_inode); int ret = -EINVAL; /* |