X-Git-Url: https://git.openpandora.org/cgi-bin/gitweb.cgi?p=pandora-kernel.git;a=blobdiff_plain;f=fs%2Fsplice.c;h=0559e7577a04164ececffdcdbd57089d980dd586;hp=6081cf7d2d1ba91c0b5d613904994cdd6876b8b9;hb=55308c3712f56279d5547ef6e97d365ac3ab9e6d;hpb=9c8680e2cfbb60d5075f8caaf9d98276120bcc78 diff --git a/fs/splice.c b/fs/splice.c index 6081cf7d2d1b..0559e7577a04 100644 --- a/fs/splice.c +++ b/fs/splice.c @@ -9,11 +9,12 @@ * that transfers data buffers to or from a pipe buffer. * * Named by Larry McVoy, original implementation from Linus, extended by - * Jens to support splicing to files and fixing the initial implementation - * bugs. + * Jens to support splicing to files, network, direct splicing, etc and + * fixing lots of bugs. * - * Copyright (C) 2005 Jens Axboe - * Copyright (C) 2005 Linus Torvalds + * Copyright (C) 2005-2006 Jens Axboe + * Copyright (C) 2005-2006 Linus Torvalds + * Copyright (C) 2006 Ingo Molnar * */ #include @@ -22,7 +23,10 @@ #include #include #include +#include +#include #include +#include /* * Passed to the actors @@ -34,28 +38,40 @@ struct splice_desc { loff_t pos; /* file position */ }; +/* + * Attempt to steal a page from a pipe buffer. This should perhaps go into + * a vm helper function, it's already simplified quite a bit by the + * addition of remove_mapping(). If success is returned, the caller may + * attempt to reuse this page for another destination. + */ static int page_cache_pipe_buf_steal(struct pipe_inode_info *info, struct pipe_buffer *buf) { struct page *page = buf->page; + struct address_space *mapping = page_mapping(page); + + lock_page(page); - WARN_ON(!PageLocked(page)); WARN_ON(!PageUptodate(page)); - if (!remove_mapping(page_mapping(page), page)) - return 1; + /* + * At least for ext2 with nobh option, we need to wait on writeback + * completing on this page, since we'll remove it from the pagecache. + * Otherwise truncate wont wait on the page, allowing the disk + * blocks to be reused by someone else before we actually wrote our + * data to them. fs corruption ensues. + */ + wait_on_page_writeback(page); - if (PageLRU(page)) { - struct zone *zone = page_zone(page); + if (PagePrivate(page)) + try_to_release_page(page, mapping_gfp_mask(mapping)); - spin_lock_irq(&zone->lru_lock); - BUG_ON(!PageLRU(page)); - __ClearPageLRU(page); - del_page_from_lru(zone, page); - spin_unlock_irq(&zone->lru_lock); + if (!remove_mapping(mapping, page)) { + unlock_page(page); + return 1; } - buf->stolen = 1; + buf->flags |= PIPE_BUF_FLAG_STOLEN | PIPE_BUF_FLAG_LRU; return 0; } @@ -64,7 +80,7 @@ static void page_cache_pipe_buf_release(struct pipe_inode_info *info, { page_cache_release(buf->page); buf->page = NULL; - buf->stolen = 0; + buf->flags &= ~(PIPE_BUF_FLAG_STOLEN | PIPE_BUF_FLAG_LRU); } static void *page_cache_pipe_buf_map(struct file *file, @@ -72,66 +88,89 @@ static void *page_cache_pipe_buf_map(struct file *file, struct pipe_buffer *buf) { struct page *page = buf->page; - - lock_page(page); + int err; if (!PageUptodate(page)) { - unlock_page(page); - return ERR_PTR(-EIO); - } + lock_page(page); - if (!page->mapping) { + /* + * Page got truncated/unhashed. This will cause a 0-byte + * splice, if this is the first page. + */ + if (!page->mapping) { + err = -ENODATA; + goto error; + } + + /* + * Uh oh, read-error from disk. + */ + if (!PageUptodate(page)) { + err = -EIO; + goto error; + } + + /* + * Page is ok afterall, fall through to mapping. + */ unlock_page(page); - return ERR_PTR(-ENODATA); } - return kmap(buf->page); + return kmap(page); +error: + unlock_page(page); + return ERR_PTR(err); } static void page_cache_pipe_buf_unmap(struct pipe_inode_info *info, struct pipe_buffer *buf) { - if (!buf->stolen) - unlock_page(buf->page); kunmap(buf->page); } +static void page_cache_pipe_buf_get(struct pipe_inode_info *info, + struct pipe_buffer *buf) +{ + page_cache_get(buf->page); +} + static struct pipe_buf_operations page_cache_pipe_buf_ops = { .can_merge = 0, .map = page_cache_pipe_buf_map, .unmap = page_cache_pipe_buf_unmap, .release = page_cache_pipe_buf_release, .steal = page_cache_pipe_buf_steal, + .get = page_cache_pipe_buf_get, }; -static ssize_t move_to_pipe(struct inode *inode, struct page **pages, - int nr_pages, unsigned long offset, - unsigned long len, unsigned int flags) +/* + * Pipe output worker. This sets up our pipe format with the page cache + * pipe buffer operations. Otherwise very similar to the regular pipe_writev(). + */ +static ssize_t move_to_pipe(struct pipe_inode_info *pipe, struct page **pages, + int nr_pages, unsigned long len, + unsigned int offset, unsigned int flags) { - struct pipe_inode_info *info; int ret, do_wakeup, i; ret = 0; do_wakeup = 0; i = 0; - mutex_lock(PIPE_MUTEX(*inode)); + if (pipe->inode) + mutex_lock(&pipe->inode->i_mutex); - info = inode->i_pipe; for (;;) { - int bufs; - - if (!PIPE_READERS(*inode)) { + if (!pipe->readers) { send_sig(SIGPIPE, current, 0); if (!ret) ret = -EPIPE; break; } - bufs = info->nrbufs; - if (bufs < PIPE_BUFFERS) { - int newbuf = (info->curbuf + bufs) & (PIPE_BUFFERS - 1); - struct pipe_buffer *buf = info->bufs + newbuf; + if (pipe->nrbufs < PIPE_BUFFERS) { + int newbuf = (pipe->curbuf + pipe->nrbufs) & (PIPE_BUFFERS - 1); + struct pipe_buffer *buf = pipe->bufs + newbuf; struct page *page = pages[i++]; unsigned long this_len; @@ -143,8 +182,9 @@ static ssize_t move_to_pipe(struct inode *inode, struct page **pages, buf->offset = offset; buf->len = this_len; buf->ops = &page_cache_pipe_buf_ops; - info->nrbufs = ++bufs; - do_wakeup = 1; + pipe->nrbufs++; + if (pipe->inode) + do_wakeup = 1; ret += this_len; len -= this_len; @@ -153,7 +193,7 @@ static ssize_t move_to_pipe(struct inode *inode, struct page **pages, break; if (!len) break; - if (bufs < PIPE_BUFFERS) + if (pipe->nrbufs < PIPE_BUFFERS) continue; break; @@ -172,22 +212,26 @@ static ssize_t move_to_pipe(struct inode *inode, struct page **pages, } if (do_wakeup) { - wake_up_interruptible_sync(PIPE_WAIT(*inode)); - kill_fasync(PIPE_FASYNC_READERS(*inode), SIGIO, - POLL_IN); + smp_mb(); + if (waitqueue_active(&pipe->wait)) + wake_up_interruptible_sync(&pipe->wait); + kill_fasync(&pipe->fasync_readers, SIGIO, POLL_IN); do_wakeup = 0; } - PIPE_WAITING_WRITERS(*inode)++; - pipe_wait(inode); - PIPE_WAITING_WRITERS(*inode)--; + pipe->waiting_writers++; + pipe_wait(pipe); + pipe->waiting_writers--; } - mutex_unlock(PIPE_MUTEX(*inode)); + if (pipe->inode) + mutex_unlock(&pipe->inode->i_mutex); if (do_wakeup) { - wake_up_interruptible(PIPE_WAIT(*inode)); - kill_fasync(PIPE_FASYNC_READERS(*inode), SIGIO, POLL_IN); + smp_mb(); + if (waitqueue_active(&pipe->wait)) + wake_up_interruptible(&pipe->wait); + kill_fasync(&pipe->fasync_readers, SIGIO, POLL_IN); } while (i < nr_pages) @@ -196,120 +240,193 @@ static ssize_t move_to_pipe(struct inode *inode, struct page **pages, return ret; } -static int __generic_file_splice_read(struct file *in, struct inode *pipe, - size_t len, unsigned int flags) +static int +__generic_file_splice_read(struct file *in, loff_t *ppos, + struct pipe_inode_info *pipe, size_t len, + unsigned int flags) { struct address_space *mapping = in->f_mapping; - unsigned int offset, nr_pages; - struct page *pages[PIPE_BUFFERS], *shadow[PIPE_BUFFERS]; + unsigned int loff, offset, nr_pages; + struct page *pages[PIPE_BUFFERS]; struct page *page; - pgoff_t index, pidx; - int i, j; + pgoff_t index, end_index; + loff_t isize; + size_t bytes; + int i, error; - index = in->f_pos >> PAGE_CACHE_SHIFT; - offset = in->f_pos & ~PAGE_CACHE_MASK; + index = *ppos >> PAGE_CACHE_SHIFT; + loff = offset = *ppos & ~PAGE_CACHE_MASK; nr_pages = (len + offset + PAGE_CACHE_SIZE - 1) >> PAGE_CACHE_SHIFT; if (nr_pages > PIPE_BUFFERS) nr_pages = PIPE_BUFFERS; /* - * initiate read-ahead on this page range + * Initiate read-ahead on this page range. however, don't call into + * read-ahead if this is a non-zero offset (we are likely doing small + * chunk splice and the page is already there) for a single page. */ - do_page_cache_readahead(mapping, in, index, nr_pages); + if (!offset || nr_pages > 1) + do_page_cache_readahead(mapping, in, index, nr_pages); /* - * Get as many pages from the page cache as possible.. - * Start IO on the page cache entries we create (we - * can assume that any pre-existing ones we find have - * already had IO started on them). + * Now fill in the holes: */ - i = find_get_pages(mapping, index, nr_pages, pages); + error = 0; + bytes = 0; + for (i = 0; i < nr_pages; i++, index++) { + unsigned int this_len; - /* - * common case - we found all pages and they are contiguous, - * kick them off - */ - if (i && (pages[i - 1]->index == index + i - 1)) - goto splice_them; + if (!len) + break; - /* - * fill shadow[] with pages at the right locations, so we only - * have to fill holes - */ - memset(shadow, 0, i * sizeof(struct page *)); - for (j = 0, pidx = index; j < i; pidx++, j++) - shadow[pages[j]->index - pidx] = pages[j]; + /* + * this_len is the max we'll use from this page + */ + this_len = min(len, PAGE_CACHE_SIZE - loff); +find_page: + /* + * lookup the page for this index + */ + page = find_get_page(mapping, index); + if (!page) { + /* + * page didn't exist, allocate one + */ + page = page_cache_alloc_cold(mapping); + if (!page) + break; - /* - * now fill in the holes - */ - for (i = 0, pidx = index; i < nr_pages; pidx++, i++) { - int error; + error = add_to_page_cache_lru(page, mapping, index, + mapping_gfp_mask(mapping)); + if (unlikely(error)) { + page_cache_release(page); + break; + } - if (shadow[i]) - continue; + goto readpage; + } /* - * no page there, look one up / create it + * If the page isn't uptodate, we may need to start io on it */ - page = find_or_create_page(mapping, pidx, - mapping_gfp_mask(mapping)); - if (!page) - break; + if (!PageUptodate(page)) { + /* + * If in nonblock mode then dont block on waiting + * for an in-flight io page + */ + if (flags & SPLICE_F_NONBLOCK) + break; + + lock_page(page); - if (PageUptodate(page)) - unlock_page(page); - else { + /* + * page was truncated, stop here. if this isn't the + * first page, we'll just complete what we already + * added + */ + if (!page->mapping) { + unlock_page(page); + page_cache_release(page); + break; + } + /* + * page was already under io and is now done, great + */ + if (PageUptodate(page)) { + unlock_page(page); + goto fill_it; + } + +readpage: + /* + * need to read in the page + */ error = mapping->a_ops->readpage(in, page); if (unlikely(error)) { + page_cache_release(page); + if (error == AOP_TRUNCATED_PAGE) + goto find_page; + break; + } + + /* + * i_size must be checked after ->readpage(). + */ + isize = i_size_read(mapping->host); + end_index = (isize - 1) >> PAGE_CACHE_SHIFT; + if (unlikely(!isize || index > end_index)) { page_cache_release(page); break; } - } - shadow[i] = page; - } - if (!i) { - for (i = 0; i < nr_pages; i++) { - if (shadow[i]) - page_cache_release(shadow[i]); + /* + * if this is the last page, see if we need to shrink + * the length and stop + */ + if (end_index == index) { + loff = PAGE_CACHE_SIZE - (isize & ~PAGE_CACHE_MASK); + if (bytes + loff > isize) { + page_cache_release(page); + break; + } + /* + * force quit after adding this page + */ + nr_pages = i; + this_len = min(this_len, loff); + } } - return 0; +fill_it: + pages[i] = page; + bytes += this_len; + len -= this_len; + loff = 0; } - memcpy(pages, shadow, i * sizeof(struct page *)); + if (i) + return move_to_pipe(pipe, pages, i, bytes, offset, flags); - /* - * Now we splice them into the pipe.. - */ -splice_them: - return move_to_pipe(pipe, pages, i, offset, len, flags); + return error; } -ssize_t generic_file_splice_read(struct file *in, struct inode *pipe, - size_t len, unsigned int flags) +/** + * generic_file_splice_read - splice data from file to a pipe + * @in: file to splice from + * @pipe: pipe to splice to + * @len: number of bytes to splice + * @flags: splice modifier flags + * + * Will read pages from given file and fill them into a pipe. + */ +ssize_t generic_file_splice_read(struct file *in, loff_t *ppos, + struct pipe_inode_info *pipe, size_t len, + unsigned int flags) { ssize_t spliced; int ret; ret = 0; spliced = 0; + while (len) { - ret = __generic_file_splice_read(in, pipe, len, flags); + ret = __generic_file_splice_read(in, ppos, pipe, len, flags); - if (ret <= 0) + if (ret < 0) break; + else if (!ret) { + if (spliced) + break; + if (flags & SPLICE_F_NONBLOCK) { + ret = -EAGAIN; + break; + } + } - in->f_pos += ret; + *ppos += ret; len -= ret; spliced += ret; - - if (!(flags & SPLICE_F_NONBLOCK)) - continue; - ret = -EAGAIN; - break; } if (spliced) @@ -318,8 +435,11 @@ ssize_t generic_file_splice_read(struct file *in, struct inode *pipe, return ret; } +EXPORT_SYMBOL(generic_file_splice_read); + /* - * Send 'len' bytes to socket from 'file' at position 'pos' using sendpage(). + * Send 'sd->len' bytes to socket from 'sd->file' at position 'sd->pos' + * using sendpage(). */ static int pipe_to_sendpage(struct pipe_inode_info *info, struct pipe_buffer *buf, struct splice_desc *sd) @@ -329,21 +449,22 @@ static int pipe_to_sendpage(struct pipe_inode_info *info, unsigned int offset; ssize_t ret; void *ptr; + int more; /* - * sub-optimal, but we are limited by the pipe ->map. we don't + * Sub-optimal, but we are limited by the pipe ->map. We don't * need a kmap'ed buffer here, we just want to make sure we * have the page pinned if the pipe page originates from the - * page cache + * page cache. */ ptr = buf->ops->map(file, info, buf); if (IS_ERR(ptr)) return PTR_ERR(ptr); offset = pos & ~PAGE_CACHE_MASK; + more = (sd->flags & SPLICE_F_MORE) || sd->len < sd->total_len; - ret = file->f_op->sendpage(file, buf->page, offset, sd->len, &pos, - sd->len < sd->total_len); + ret = file->f_op->sendpage(file, buf->page, offset, sd->len, &pos,more); buf->ops->unmap(info, buf); if (ret == sd->len) @@ -365,16 +486,19 @@ static int pipe_to_sendpage(struct pipe_inode_info *info, * - Destination page does not exist, we can add the pipe page to * the page cache and avoid the copy. * - * For now we just do the slower thing and always copy pages over, it's - * easier than migrating pages from the pipe to the target file. For the - * case of doing file | file splicing, the migrate approach had some LRU - * nastiness... + * If asked to move pages to the output file (SPLICE_F_MOVE is set in + * sd->flags), we attempt to migrate pages from the pipe to the output + * file address space page cache. This is possible if no one else has + * the pipe page referenced outside of the pipe and page cache. If + * 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 *info, struct pipe_buffer *buf, struct splice_desc *sd) { struct file *file = sd->file; struct address_space *mapping = file->f_mapping; + gfp_t gfp_mask = mapping_gfp_mask(mapping); unsigned int offset; struct page *page; pgoff_t index; @@ -382,7 +506,7 @@ static int pipe_to_file(struct pipe_inode_info *info, struct pipe_buffer *buf, int ret; /* - * after this, page will be locked and unmapped + * make sure the data in this buffer is uptodate */ src = buf->ops->map(file, info, buf); if (IS_ERR(src)) @@ -392,28 +516,46 @@ static int pipe_to_file(struct pipe_inode_info *info, struct pipe_buffer *buf, offset = sd->pos & ~PAGE_CACHE_MASK; /* - * reuse buf page, if SPLICE_F_MOVE is set + * Reuse buf page, if SPLICE_F_MOVE is set. */ if (sd->flags & SPLICE_F_MOVE) { + /* + * If steal succeeds, buf->page is now pruned from the vm + * side (LRU and page cache) and we can reuse it. The page + * will also be looked on successful return. + */ if (buf->ops->steal(info, buf)) goto find_page; page = buf->page; - if (add_to_page_cache_lru(page, mapping, index, - mapping_gfp_mask(mapping))) + if (add_to_page_cache(page, mapping, index, gfp_mask)) goto find_page; + + if (!(buf->flags & PIPE_BUF_FLAG_LRU)) + lru_cache_add(page); } else { find_page: - ret = -ENOMEM; - page = find_or_create_page(mapping, index, - mapping_gfp_mask(mapping)); - if (!page) - goto out; + page = find_lock_page(mapping, index); + if (!page) { + ret = -ENOMEM; + page = page_cache_alloc_cold(mapping); + if (unlikely(!page)) + goto out_nomem; + + /* + * This will also lock the page + */ + ret = add_to_page_cache_lru(page, mapping, index, + gfp_mask); + if (unlikely(ret)) + goto out; + } /* - * If the page is uptodate, it is also locked. If it isn't - * uptodate, we can mark it uptodate if we are filling the - * full page. Otherwise we need to read it in first... + * We get here with the page locked. If the page is also + * uptodate, we don't need to do more. If it isn't, we + * may need to bring it in if we are not going to overwrite + * the full page. */ if (!PageUptodate(page)) { if (sd->len < PAGE_CACHE_SIZE) { @@ -425,7 +567,7 @@ find_page: if (!PageUptodate(page)) { /* - * page got invalidated, repeat + * Page got invalidated, repeat. */ if (!page->mapping) { unlock_page(page); @@ -435,18 +577,19 @@ find_page: ret = -EIO; goto out; } - } else { - WARN_ON(!PageLocked(page)); + } else SetPageUptodate(page); - } } } ret = mapping->a_ops->prepare_write(file, page, 0, sd->len); - if (ret) + if (ret == AOP_TRUNCATED_PAGE) { + page_cache_release(page); + goto find_page; + } else if (ret) goto out; - if (!buf->stolen) { + if (!(buf->flags & PIPE_BUF_FLAG_STOLEN)) { char *dst = kmap_atomic(page, KM_USER0); memcpy(dst + offset, src + buf->offset, sd->len); @@ -455,16 +598,20 @@ find_page: } ret = mapping->a_ops->commit_write(file, page, 0, sd->len); - if (ret < 0) + if (ret == AOP_TRUNCATED_PAGE) { + page_cache_release(page); + goto find_page; + } else if (ret) goto out; - set_page_dirty(page); - ret = write_one_page(page, 0); + mark_page_accessed(page); + balance_dirty_pages_ratelimited(mapping); out: - if (ret < 0) - unlock_page(page); - if (!buf->stolen) + if (!(buf->flags & PIPE_BUF_FLAG_STOLEN)) page_cache_release(page); + + unlock_page(page); +out_nomem: buf->ops->unmap(info, buf); return ret; } @@ -472,11 +619,15 @@ out: typedef int (splice_actor)(struct pipe_inode_info *, struct pipe_buffer *, struct splice_desc *); -static ssize_t move_from_pipe(struct inode *inode, struct file *out, - size_t len, unsigned int flags, +/* + * Pipe input worker. Most of this logic works like a regular pipe, the + * 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. + */ +static ssize_t move_from_pipe(struct pipe_inode_info *pipe, struct file *out, + loff_t *ppos, size_t len, unsigned int flags, splice_actor *actor) { - struct pipe_inode_info *info; int ret, do_wakeup, err; struct splice_desc sd; @@ -486,24 +637,21 @@ static ssize_t move_from_pipe(struct inode *inode, struct file *out, sd.total_len = len; sd.flags = flags; sd.file = out; - sd.pos = out->f_pos; + sd.pos = *ppos; - mutex_lock(PIPE_MUTEX(*inode)); + if (pipe->inode) + mutex_lock(&pipe->inode->i_mutex); - info = inode->i_pipe; for (;;) { - int bufs = info->nrbufs; - - if (bufs) { - int curbuf = info->curbuf; - struct pipe_buffer *buf = info->bufs + curbuf; + if (pipe->nrbufs) { + struct pipe_buffer *buf = pipe->bufs + pipe->curbuf; struct pipe_buf_operations *ops = buf->ops; sd.len = buf->len; if (sd.len > sd.total_len) sd.len = sd.total_len; - err = actor(info, buf, &sd); + err = actor(pipe, buf, &sd); if (err) { if (!ret && err != -ENODATA) ret = err; @@ -514,13 +662,14 @@ static ssize_t move_from_pipe(struct inode *inode, struct file *out, ret += sd.len; buf->offset += sd.len; buf->len -= sd.len; + if (!buf->len) { buf->ops = NULL; - ops->release(info, buf); - curbuf = (curbuf + 1) & (PIPE_BUFFERS - 1); - info->curbuf = curbuf; - info->nrbufs = --bufs; - do_wakeup = 1; + ops->release(pipe, buf); + pipe->curbuf = (pipe->curbuf + 1) & (PIPE_BUFFERS - 1); + pipe->nrbufs--; + if (pipe->inode) + do_wakeup = 1; } sd.pos += sd.len; @@ -529,11 +678,11 @@ static ssize_t move_from_pipe(struct inode *inode, struct file *out, break; } - if (bufs) + if (pipe->nrbufs) continue; - if (!PIPE_WRITERS(*inode)) + if (!pipe->writers) break; - if (!PIPE_WAITING_WRITERS(*inode)) { + if (!pipe->waiting_writers) { if (ret) break; } @@ -551,108 +700,319 @@ static ssize_t move_from_pipe(struct inode *inode, struct file *out, } if (do_wakeup) { - wake_up_interruptible_sync(PIPE_WAIT(*inode)); - kill_fasync(PIPE_FASYNC_WRITERS(*inode),SIGIO,POLL_OUT); + smp_mb(); + if (waitqueue_active(&pipe->wait)) + wake_up_interruptible_sync(&pipe->wait); + kill_fasync(&pipe->fasync_writers, SIGIO, POLL_OUT); do_wakeup = 0; } - pipe_wait(inode); + pipe_wait(pipe); } - mutex_unlock(PIPE_MUTEX(*inode)); + if (pipe->inode) + mutex_unlock(&pipe->inode->i_mutex); if (do_wakeup) { - wake_up_interruptible(PIPE_WAIT(*inode)); - kill_fasync(PIPE_FASYNC_WRITERS(*inode), SIGIO, POLL_OUT); + smp_mb(); + if (waitqueue_active(&pipe->wait)) + wake_up_interruptible(&pipe->wait); + kill_fasync(&pipe->fasync_writers, SIGIO, POLL_OUT); } - mutex_lock(&out->f_mapping->host->i_mutex); - out->f_pos = sd.pos; - mutex_unlock(&out->f_mapping->host->i_mutex); return ret; - } -ssize_t generic_file_splice_write(struct inode *inode, struct file *out, - size_t len, unsigned int flags) +/** + * generic_file_splice_write - splice data from a pipe to a file + * @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. + * + */ +ssize_t +generic_file_splice_write(struct pipe_inode_info *pipe, struct file *out, + loff_t *ppos, size_t len, unsigned int flags) { - return move_from_pipe(inode, out, len, flags, pipe_to_file); + struct address_space *mapping = out->f_mapping; + ssize_t ret; + + ret = move_from_pipe(pipe, out, ppos, len, flags, pipe_to_file); + if (ret > 0) { + struct inode *inode = mapping->host; + + *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))) { + int err; + + mutex_lock(&inode->i_mutex); + err = generic_osync_inode(inode, mapping, + OSYNC_METADATA|OSYNC_DATA); + mutex_unlock(&inode->i_mutex); + + if (err) + ret = err; + } + } + + return ret; } -ssize_t generic_splice_sendpage(struct inode *inode, struct file *out, - size_t len, unsigned int flags) +EXPORT_SYMBOL(generic_file_splice_write); + +/** + * generic_splice_sendpage - splice data from a pipe to a socket + * @inode: pipe inode + * @out: socket to write to + * @len: number of bytes to splice + * @flags: splice modifier flags + * + * Will send @len bytes from the pipe to a network socket. No data copying + * is involved. + * + */ +ssize_t generic_splice_sendpage(struct pipe_inode_info *pipe, struct file *out, + loff_t *ppos, size_t len, unsigned int flags) { - return move_from_pipe(inode, out, len, flags, pipe_to_sendpage); + return move_from_pipe(pipe, out, ppos, len, flags, pipe_to_sendpage); } -EXPORT_SYMBOL(generic_file_splice_write); -EXPORT_SYMBOL(generic_file_splice_read); +EXPORT_SYMBOL(generic_splice_sendpage); -static long do_splice_from(struct inode *pipe, struct file *out, size_t len, - unsigned int flags) +/* + * Attempt to initiate a splice from pipe to file. + */ +static long do_splice_from(struct pipe_inode_info *pipe, struct file *out, + loff_t *ppos, size_t len, unsigned int flags) { - loff_t pos; int ret; - if (!out->f_op || !out->f_op->splice_write) + if (unlikely(!out->f_op || !out->f_op->splice_write)) return -EINVAL; - if (!(out->f_mode & FMODE_WRITE)) + if (unlikely(!(out->f_mode & FMODE_WRITE))) return -EBADF; - pos = out->f_pos; - ret = rw_verify_area(WRITE, out, &pos, len); + ret = rw_verify_area(WRITE, out, ppos, len); if (unlikely(ret < 0)) return ret; - return out->f_op->splice_write(pipe, out, len, flags); + return out->f_op->splice_write(pipe, out, ppos, len, flags); } -static long do_splice_to(struct file *in, struct inode *pipe, size_t len, +/* + * Attempt to initiate a splice from a file to a pipe. + */ +static long do_splice_to(struct file *in, loff_t *ppos, + struct pipe_inode_info *pipe, size_t len, unsigned int flags) { - loff_t pos, isize, left; + loff_t isize, left; int ret; - if (!in->f_op || !in->f_op->splice_read) + if (unlikely(!in->f_op || !in->f_op->splice_read)) return -EINVAL; - if (!(in->f_mode & FMODE_READ)) + if (unlikely(!(in->f_mode & FMODE_READ))) return -EBADF; - pos = in->f_pos; - ret = rw_verify_area(READ, in, &pos, len); + ret = rw_verify_area(READ, in, ppos, len); if (unlikely(ret < 0)) return ret; isize = i_size_read(in->f_mapping->host); - if (unlikely(in->f_pos >= isize)) + if (unlikely(*ppos >= isize)) return 0; - left = isize - in->f_pos; - if (left < len) + left = isize - *ppos; + if (unlikely(left < len)) len = left; - return in->f_op->splice_read(in, pipe, len, flags); + return in->f_op->splice_read(in, ppos, pipe, len, flags); +} + +long do_splice_direct(struct file *in, loff_t *ppos, struct file *out, + size_t len, unsigned int flags) +{ + struct pipe_inode_info *pipe; + long ret, bytes; + loff_t out_off; + umode_t i_mode; + int i; + + /* + * We require the input being a regular file, as we don't want to + * randomly drop data for eg socket -> socket splicing. Use the + * piped splicing for that! + */ + i_mode = in->f_dentry->d_inode->i_mode; + if (unlikely(!S_ISREG(i_mode) && !S_ISBLK(i_mode))) + return -EINVAL; + + /* + * neither in nor out is a pipe, setup an internal pipe attached to + * 'out' and transfer the wanted data from 'in' to 'out' through that + */ + pipe = current->splice_pipe; + if (unlikely(!pipe)) { + pipe = alloc_pipe_info(NULL); + if (!pipe) + return -ENOMEM; + + /* + * We don't have an immediate reader, but we'll read the stuff + * out of the pipe right after the move_to_pipe(). So set + * PIPE_READERS appropriately. + */ + pipe->readers = 1; + + current->splice_pipe = pipe; + } + + /* + * Do the splice. + */ + ret = 0; + bytes = 0; + out_off = 0; + + while (len) { + size_t read_len, max_read_len; + + /* + * Do at most PIPE_BUFFERS pages worth of transfer: + */ + max_read_len = min(len, (size_t)(PIPE_BUFFERS*PAGE_SIZE)); + + ret = do_splice_to(in, ppos, pipe, max_read_len, flags); + if (unlikely(ret < 0)) + goto out_release; + + read_len = ret; + + /* + * NOTE: nonblocking mode only applies to the input. We + * must not do the output in nonblocking mode as then we + * could get stuck data in the internal pipe: + */ + ret = do_splice_from(pipe, out, &out_off, read_len, + flags & ~SPLICE_F_NONBLOCK); + if (unlikely(ret < 0)) + goto out_release; + + bytes += ret; + len -= ret; + + /* + * In nonblocking mode, if we got back a short read then + * that was due to either an IO error or due to the + * pagecache entry not being there. In the IO error case + * the _next_ splice attempt will produce a clean IO error + * return value (not a short read), so in both cases it's + * correct to break out of the loop here: + */ + if ((flags & SPLICE_F_NONBLOCK) && (read_len < max_read_len)) + break; + } + + pipe->nrbufs = pipe->curbuf = 0; + + return bytes; + +out_release: + /* + * If we did an incomplete transfer we must release + * the pipe buffers in question: + */ + for (i = 0; i < PIPE_BUFFERS; i++) { + struct pipe_buffer *buf = pipe->bufs + i; + + if (buf->ops) { + buf->ops->release(pipe, buf); + buf->ops = NULL; + } + } + pipe->nrbufs = pipe->curbuf = 0; + + /* + * If we transferred some data, return the number of bytes: + */ + if (bytes > 0) + return bytes; + + return ret; } -static long do_splice(struct file *in, struct file *out, size_t len, - unsigned int flags) +EXPORT_SYMBOL(do_splice_direct); + +/* + * Determine where to splice to/from. + */ +static long do_splice(struct file *in, loff_t __user *off_in, + struct file *out, loff_t __user *off_out, + size_t len, unsigned int flags) { - struct inode *pipe; + struct pipe_inode_info *pipe; + loff_t offset, *off; + long ret; + + pipe = in->f_dentry->d_inode->i_pipe; + if (pipe) { + if (off_in) + return -ESPIPE; + if (off_out) { + if (out->f_op->llseek == no_llseek) + return -EINVAL; + if (copy_from_user(&offset, off_out, sizeof(loff_t))) + return -EFAULT; + off = &offset; + } else + off = &out->f_pos; + + ret = do_splice_from(pipe, out, off, len, flags); + + if (off_out && copy_to_user(off_out, off, sizeof(loff_t))) + ret = -EFAULT; + + return ret; + } - pipe = in->f_dentry->d_inode; - if (pipe->i_pipe) - return do_splice_from(pipe, out, len, flags); + pipe = out->f_dentry->d_inode->i_pipe; + if (pipe) { + if (off_out) + return -ESPIPE; + if (off_in) { + if (in->f_op->llseek == no_llseek) + return -EINVAL; + if (copy_from_user(&offset, off_in, sizeof(loff_t))) + return -EFAULT; + off = &offset; + } else + off = &in->f_pos; - pipe = out->f_dentry->d_inode; - if (pipe->i_pipe) - return do_splice_to(in, pipe, len, flags); + ret = do_splice_to(in, off, pipe, len, flags); + + if (off_in && copy_to_user(off_in, off, sizeof(loff_t))) + ret = -EFAULT; + + return ret; + } return -EINVAL; } -asmlinkage long sys_splice(int fdin, int fdout, size_t len, unsigned int flags) +asmlinkage long sys_splice(int fd_in, loff_t __user *off_in, + int fd_out, loff_t __user *off_out, + size_t len, unsigned int flags) { long error; struct file *in, *out; @@ -662,13 +1022,15 @@ asmlinkage long sys_splice(int fdin, int fdout, size_t len, unsigned int flags) return 0; error = -EBADF; - in = fget_light(fdin, &fput_in); + in = fget_light(fd_in, &fput_in); if (in) { if (in->f_mode & FMODE_READ) { - out = fget_light(fdout, &fput_out); + out = fget_light(fd_out, &fput_out); if (out) { if (out->f_mode & FMODE_WRITE) - error = do_splice(in, out, len, flags); + error = do_splice(in, off_in, + out, off_out, + len, flags); fput_light(out, fput_out); } } @@ -678,3 +1040,192 @@ asmlinkage long sys_splice(int fdin, int fdout, size_t len, unsigned int flags) return error; } + +/* + * Link contents of ipipe to opipe. + */ +static int link_pipe(struct pipe_inode_info *ipipe, + struct pipe_inode_info *opipe, + size_t len, unsigned int flags) +{ + struct pipe_buffer *ibuf, *obuf; + int ret, do_wakeup, i, ipipe_first; + + ret = do_wakeup = ipipe_first = 0; + + /* + * Potential ABBA deadlock, work around it by ordering lock + * 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) { + ipipe_first = 1; + mutex_lock(&ipipe->inode->i_mutex); + mutex_lock(&opipe->inode->i_mutex); + } else { + mutex_lock(&opipe->inode->i_mutex); + mutex_lock(&ipipe->inode->i_mutex); + } + + for (i = 0;; i++) { + if (!opipe->readers) { + send_sig(SIGPIPE, current, 0); + if (!ret) + ret = -EPIPE; + break; + } + if (ipipe->nrbufs - i) { + ibuf = ipipe->bufs + ((ipipe->curbuf + i) & (PIPE_BUFFERS - 1)); + + /* + * If we have room, fill this buffer + */ + if (opipe->nrbufs < PIPE_BUFFERS) { + int nbuf = (opipe->curbuf + opipe->nrbufs) & (PIPE_BUFFERS - 1); + + /* + * Get a reference to this pipe buffer, + * so we can copy the contents over. + */ + ibuf->ops->get(ipipe, ibuf); + + obuf = opipe->bufs + nbuf; + *obuf = *ibuf; + + if (obuf->len > len) + obuf->len = len; + + opipe->nrbufs++; + do_wakeup = 1; + ret += obuf->len; + len -= obuf->len; + + if (!len) + break; + if (opipe->nrbufs < PIPE_BUFFERS) + continue; + } + + /* + * We have input available, but no output room. + * If we already copied data, return that. If we + * need to drop the opipe lock, it must be ordered + * last to avoid deadlocks. + */ + if ((flags & SPLICE_F_NONBLOCK) || !ipipe_first) { + if (!ret) + ret = -EAGAIN; + break; + } + if (signal_pending(current)) { + if (!ret) + ret = -ERESTARTSYS; + break; + } + if (do_wakeup) { + smp_mb(); + if (waitqueue_active(&opipe->wait)) + wake_up_interruptible(&opipe->wait); + kill_fasync(&opipe->fasync_readers, SIGIO, POLL_IN); + do_wakeup = 0; + } + + opipe->waiting_writers++; + pipe_wait(opipe); + opipe->waiting_writers--; + continue; + } + + /* + * No input buffers, do the usual checks for available + * writers and blocking and wait if necessary + */ + if (!ipipe->writers) + break; + if (!ipipe->waiting_writers) { + if (ret) + break; + } + /* + * pipe_wait() drops the ipipe mutex. To avoid deadlocks + * with another process, we can only safely do that if + * the ipipe lock is ordered last. + */ + if ((flags & SPLICE_F_NONBLOCK) || ipipe_first) { + if (!ret) + ret = -EAGAIN; + break; + } + if (signal_pending(current)) { + if (!ret) + ret = -ERESTARTSYS; + break; + } + + if (waitqueue_active(&ipipe->wait)) + wake_up_interruptible_sync(&ipipe->wait); + kill_fasync(&ipipe->fasync_writers, SIGIO, POLL_OUT); + + pipe_wait(ipipe); + } + + mutex_unlock(&ipipe->inode->i_mutex); + mutex_unlock(&opipe->inode->i_mutex); + + if (do_wakeup) { + smp_mb(); + if (waitqueue_active(&opipe->wait)) + wake_up_interruptible(&opipe->wait); + kill_fasync(&opipe->fasync_readers, SIGIO, POLL_IN); + } + + return ret; +} + +/* + * This is a tee(1) implementation that works on pipes. It doesn't copy + * any data, it simply references the 'in' pages on the 'out' pipe. + * The 'flags' used are the SPLICE_F_* variants, currently the only + * applicable one is SPLICE_F_NONBLOCK. + */ +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; + + /* + * Link ipipe to the two output pipes, consuming as we go along. + */ + if (ipipe && opipe) + return link_pipe(ipipe, opipe, len, flags); + + return -EINVAL; +} + +asmlinkage long sys_tee(int fdin, int fdout, size_t len, unsigned int flags) +{ + struct file *in; + int error, fput_in; + + if (unlikely(!len)) + return 0; + + error = -EBADF; + in = fget_light(fdin, &fput_in); + if (in) { + if (in->f_mode & FMODE_READ) { + int fput_out; + struct file *out = fget_light(fdout, &fput_out); + + if (out) { + if (out->f_mode & FMODE_WRITE) + error = do_tee(in, out, len, flags); + fput_light(out, fput_out); + } + } + fput_light(in, fput_in); + } + + return error; +}