* Jens to support splicing to files, network, direct splicing, etc and
* fixing lots of bugs.
*
- * Copyright (C) 2005-2006 Jens Axboe <axboe@suse.de>
+ * Copyright (C) 2005-2006 Jens Axboe <axboe@kernel.dk>
* Copyright (C) 2005-2006 Linus Torvalds <torvalds@osdl.org>
* Copyright (C) 2006 Ingo Molnar <mingo@elte.hu>
*
struct pipe_buffer *buf)
{
struct page *page = buf->page;
- struct address_space *mapping = page_mapping(page);
+ struct address_space *mapping;
lock_page(page);
- WARN_ON(!PageUptodate(page));
+ mapping = page_mapping(page);
+ if (mapping) {
+ WARN_ON(!PageUptodate(page));
- /*
- * 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);
+ /*
+ * 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 (PagePrivate(page))
- try_to_release_page(page, mapping_gfp_mask(mapping));
+ if (PagePrivate(page))
+ try_to_release_page(page, GFP_KERNEL);
- if (!remove_mapping(mapping, page)) {
- unlock_page(page);
- return 1;
+ /*
+ * If we succeeded in removing the mapping, set LRU flag
+ * and return good.
+ */
+ if (remove_mapping(mapping, page)) {
+ buf->flags |= PIPE_BUF_FLAG_LRU;
+ return 0;
+ }
}
- buf->flags |= PIPE_BUF_FLAG_LRU;
- return 0;
+ /*
+ * Raced with truncate or failed to remove page from current
+ * address space, unlock and return failure.
+ */
+ unlock_page(page);
+ return 1;
}
static void page_cache_pipe_buf_release(struct pipe_inode_info *pipe,
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)
{
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;
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;
}
ret = -ENOMEM;
page = page_cache_alloc_cold(mapping);
if (unlikely(!page))
- goto out_nomem;
+ goto out_ret;
/*
* This will also lock the page
*/
ret = add_to_page_cache_lru(page, mapping, index,
- gfp_mask);
+ GFP_KERNEL);
if (unlikely(ret))
goto out;
}
if (sd->pos + this_len > isize)
vmtruncate(mapping->host, isize);
- goto out;
+ goto out_ret;
}
if (buf->page != page) {
out:
page_cache_release(page);
unlock_page(page);
-out_nomem:
+out_ret:
return 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;
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;
pipe_wait(pipe);
}
- if (pipe->inode)
- mutex_unlock(&pipe->inode->i_mutex);
-
if (do_wakeup) {
smp_mb();
if (waitqueue_active(&pipe->wait))
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_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
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_dentry);
+ if (unlikely(err)) {
+ mutex_lock(&inode->i_mutex);
+ err = __remove_suid(out->f_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;
/*
* 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);
return error;
}
+/*
+ * Make sure there's data to read. Wait for input if we can, otherwise
+ * return an appropriate error.
+ */
+static int link_ipipe_prep(struct pipe_inode_info *pipe, unsigned int flags)
+{
+ int ret;
+
+ /*
+ * Check ->nrbufs without the inode lock first. This function
+ * is speculative anyways, so missing one is ok.
+ */
+ if (pipe->nrbufs)
+ return 0;
+
+ ret = 0;
+ mutex_lock(&pipe->inode->i_mutex);
+
+ while (!pipe->nrbufs) {
+ if (signal_pending(current)) {
+ ret = -ERESTARTSYS;
+ break;
+ }
+ if (!pipe->writers)
+ break;
+ if (!pipe->waiting_writers) {
+ if (flags & SPLICE_F_NONBLOCK) {
+ ret = -EAGAIN;
+ break;
+ }
+ }
+ pipe_wait(pipe);
+ }
+
+ mutex_unlock(&pipe->inode->i_mutex);
+ return ret;
+}
+
+/*
+ * Make sure there's writeable room. Wait for room if we can, otherwise
+ * return an appropriate error.
+ */
+static int link_opipe_prep(struct pipe_inode_info *pipe, unsigned int flags)
+{
+ int ret;
+
+ /*
+ * Check ->nrbufs without the inode lock first. This function
+ * is speculative anyways, so missing one is ok.
+ */
+ if (pipe->nrbufs < PIPE_BUFFERS)
+ return 0;
+
+ ret = 0;
+ mutex_lock(&pipe->inode->i_mutex);
+
+ while (pipe->nrbufs >= PIPE_BUFFERS) {
+ if (!pipe->readers) {
+ send_sig(SIGPIPE, current, 0);
+ ret = -EPIPE;
+ break;
+ }
+ if (flags & SPLICE_F_NONBLOCK) {
+ ret = -EAGAIN;
+ break;
+ }
+ if (signal_pending(current)) {
+ ret = -ERESTARTSYS;
+ break;
+ }
+ pipe->waiting_writers++;
+ pipe_wait(pipe);
+ pipe->waiting_writers--;
+ }
+
+ mutex_unlock(&pipe->inode->i_mutex);
+ return ret;
+}
+
/*
* Link contents of ipipe to 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;
+ int ret = 0, i = 0, nbuf;
/*
* 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);
- }
+ inode_double_lock(ipipe->inode, opipe->inode);
- for (i = 0;; i++) {
+ do {
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;
-
- /*
- * Don't inherit the gift flag, we need to
- * prevent multiple steals of this page.
- */
- obuf->flags &= ~PIPE_BUF_FLAG_GIFT;
- 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;
- }
+ /*
+ * If we have iterated all input buffers or ran out of
+ * output room, break.
+ */
+ if (i >= ipipe->nrbufs || opipe->nrbufs >= PIPE_BUFFERS)
+ break;
- opipe->waiting_writers++;
- pipe_wait(opipe);
- opipe->waiting_writers--;
- continue;
- }
+ ibuf = ipipe->bufs + ((ipipe->curbuf + i) & (PIPE_BUFFERS - 1));
+ nbuf = (opipe->curbuf + opipe->nrbufs) & (PIPE_BUFFERS - 1);
/*
- * No input buffers, do the usual checks for available
- * writers and blocking and wait if necessary
+ * Get a reference to this pipe buffer,
+ * so we can copy the contents over.
*/
- if (!ipipe->writers)
- break;
- if (!ipipe->waiting_writers) {
- if (ret)
- break;
- }
+ ibuf->ops->get(ipipe, ibuf);
+
+ obuf = opipe->bufs + nbuf;
+ *obuf = *ibuf;
+
/*
- * 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.
+ * Don't inherit the gift flag, we need to
+ * prevent multiple steals of this page.
*/
- if ((flags & SPLICE_F_NONBLOCK) || ipipe_first) {
- if (!ret)
- ret = -EAGAIN;
- break;
- }
- if (signal_pending(current)) {
- if (!ret)
- ret = -ERESTARTSYS;
- break;
- }
+ obuf->flags &= ~PIPE_BUF_FLAG_GIFT;
- if (waitqueue_active(&ipipe->wait))
- wake_up_interruptible_sync(&ipipe->wait);
- kill_fasync(&ipipe->fasync_writers, SIGIO, POLL_OUT);
+ if (obuf->len > len)
+ obuf->len = len;
- pipe_wait(ipipe);
- }
+ opipe->nrbufs++;
+ ret += obuf->len;
+ len -= obuf->len;
+ i++;
+ } while (len);
- mutex_unlock(&ipipe->inode->i_mutex);
- mutex_unlock(&opipe->inode->i_mutex);
+ inode_double_unlock(ipipe->inode, opipe->inode);
- if (do_wakeup) {
+ /*
+ * If we put data in the output pipe, wakeup any potential readers.
+ */
+ if (ret > 0) {
smp_mb();
if (waitqueue_active(&opipe->wait))
wake_up_interruptible(&opipe->wait);
{
struct pipe_inode_info *ipipe = in->f_dentry->d_inode->i_pipe;
struct pipe_inode_info *opipe = out->f_dentry->d_inode->i_pipe;
+ int ret = -EINVAL;
/*
- * Link ipipe to the two output pipes, consuming as we go along.
+ * Duplicate the contents of ipipe to opipe without actually
+ * copying the data.
*/
- if (ipipe && opipe)
- return link_pipe(ipipe, opipe, len, flags);
+ if (ipipe && opipe && ipipe != opipe) {
+ /*
+ * Keep going, unless we encounter an error. The ipipe/opipe
+ * ordering doesn't really matter.
+ */
+ ret = link_ipipe_prep(ipipe, flags);
+ if (!ret) {
+ ret = link_opipe_prep(opipe, flags);
+ if (!ret) {
+ ret = link_pipe(ipipe, opipe, len, flags);
+ if (!ret && (flags & SPLICE_F_NONBLOCK))
+ ret = -EAGAIN;
+ }
+ }
+ }
- return -EINVAL;
+ return ret;
}
asmlinkage long sys_tee(int fdin, int fdout, size_t len, unsigned int flags)
git.openpandora.org / pandora-kernel.git / blobdiff