1 files changed, 178 insertions, 128 deletions

diff --git a/fs/splice.c b/fs/splice.c
index 447ebc0a37f3..a285fd746dc0 100644
--- a/fs/splice.c
+++ b/fs/splice.c
@@ -51,7 +51,7 @@ struct splice_pipe_desc {
  * 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,
+static int page_cache_pipe_buf_steal(struct pipe_inode_info *pipe,
                                      struct pipe_buffer *buf)
 {
         struct page *page = buf->page;
@@ -78,21 +78,19 @@ static int page_cache_pipe_buf_steal(struct pipe_inode_info *info,
                 return 1;
         }
 
-        buf->flags |= PIPE_BUF_FLAG_STOLEN | PIPE_BUF_FLAG_LRU;
+        buf->flags |= PIPE_BUF_FLAG_LRU;
         return 0;
 }
 
-static void page_cache_pipe_buf_release(struct pipe_inode_info *info,
+static void page_cache_pipe_buf_release(struct pipe_inode_info *pipe,
                                         struct pipe_buffer *buf)
 {
         page_cache_release(buf->page);
-        buf->page = NULL;
-        buf->flags &= ~(PIPE_BUF_FLAG_STOLEN | PIPE_BUF_FLAG_LRU);
+        buf->flags &= ~PIPE_BUF_FLAG_LRU;
 }
 
-static void *page_cache_pipe_buf_map(struct file *file,
-                                     struct pipe_inode_info *info,
-                                     struct pipe_buffer *buf)
+static int page_cache_pipe_buf_pin(struct pipe_inode_info *pipe,
+                                   struct pipe_buffer *buf)
 {
         struct page *page = buf->page;
         int err;
@@ -118,64 +116,45 @@ static void *page_cache_pipe_buf_map(struct file *file,
                 }
 
                 /*
-                 * Page is ok afterall, fall through to mapping.
+                 * Page is ok afterall, we are done.
                  */
                 unlock_page(page);
         }
 
-        return kmap(page);
+        return 0;
 error:
         unlock_page(page);
-        return ERR_PTR(err);
-}
-
-static void page_cache_pipe_buf_unmap(struct pipe_inode_info *info,
-                                      struct pipe_buffer *buf)
-{
-        kunmap(buf->page);
-}
-
-static void *user_page_pipe_buf_map(struct file *file,
-                                    struct pipe_inode_info *pipe,
-                                    struct pipe_buffer *buf)
-{
-        return kmap(buf->page);
-}
-
-static void user_page_pipe_buf_unmap(struct pipe_inode_info *pipe,
-                                     struct pipe_buffer *buf)
-{
-        kunmap(buf->page);
-}
-
-static void page_cache_pipe_buf_get(struct pipe_inode_info *info,
-                                    struct pipe_buffer *buf)
-{
-        page_cache_get(buf->page);
+        return err;
 }
 
 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,
+        .map = generic_pipe_buf_map,
+        .unmap = generic_pipe_buf_unmap,
+        .pin = page_cache_pipe_buf_pin,
         .release = page_cache_pipe_buf_release,
         .steal = page_cache_pipe_buf_steal,
-        .get = page_cache_pipe_buf_get,
+        .get = generic_pipe_buf_get,
 };
 
 static int user_page_pipe_buf_steal(struct pipe_inode_info *pipe,
                                     struct pipe_buffer *buf)
 {
-        return 1;
+        if (!(buf->flags & PIPE_BUF_FLAG_GIFT))
+                return 1;
+
+        buf->flags |= PIPE_BUF_FLAG_LRU;
+        return generic_pipe_buf_steal(pipe, buf);
 }
 
 static struct pipe_buf_operations user_page_pipe_buf_ops = {
         .can_merge = 0,
-        .map = user_page_pipe_buf_map,
-        .unmap = user_page_pipe_buf_unmap,
+        .map = generic_pipe_buf_map,
+        .unmap = generic_pipe_buf_unmap,
+        .pin = generic_pipe_buf_pin,
         .release = page_cache_pipe_buf_release,
         .steal = user_page_pipe_buf_steal,
-        .get = page_cache_pipe_buf_get,
+        .get = generic_pipe_buf_get,
 };
 
 /*
@@ -210,6 +189,9 @@ static ssize_t splice_to_pipe(struct pipe_inode_info *pipe,
                         buf->offset = spd->partial[page_nr].offset;
                         buf->len = spd->partial[page_nr].len;
                         buf->ops = spd->ops;
+                        if (spd->flags & SPLICE_F_GIFT)
+                                buf->flags |= PIPE_BUF_FLAG_GIFT;
+
                         pipe->nrbufs++;
                         page_nr++;
                         ret += buf->len;
@@ -279,7 +261,7 @@ __generic_file_splice_read(struct file *in, loff_t *ppos,
         pgoff_t index, end_index;
         loff_t isize;
         size_t total_len;
-        int error;
+        int error, page_nr;
         struct splice_pipe_desc spd = {
                 .pages = pages,
                 .partial = partial,
@@ -299,47 +281,83 @@ __generic_file_splice_read(struct file *in, loff_t *ppos,
          * 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.
          */
-        if (!loff || spd.nr_pages > 1)
-                do_page_cache_readahead(mapping, in, index, spd.nr_pages);
+        if (!loff || nr_pages > 1)
+                page_cache_readahead(mapping, &in->f_ra, in, index, nr_pages);
 
         /*
          * Now fill in the holes:
          */
         error = 0;
         total_len = 0;
-        for (spd.nr_pages = 0; spd.nr_pages < nr_pages; spd.nr_pages++, index++) {
-                unsigned int this_len;
 
-                if (!len)
-                        break;
+        /*
+         * Lookup the (hopefully) full range of pages we need.
+         */
+        spd.nr_pages = find_get_pages_contig(mapping, index, nr_pages, pages);
 
+        /*
+         * If find_get_pages_contig() returned fewer pages than we needed,
+         * allocate the rest.
+         */
+        index += spd.nr_pages;
+        while (spd.nr_pages < nr_pages) {
                 /*
-                 * this_len is the max we'll use from this page
-                 */
-                this_len = min_t(unsigned long, len, PAGE_CACHE_SIZE - loff);
-find_page:
-                /*
-                 * lookup the page for this index
+                 * Page could be there, find_get_pages_contig() breaks on
+                 * the first hole.
                  */
                 page = find_get_page(mapping, index);
                 if (!page) {
                         /*
-                         * page didn't exist, allocate one
+                         * Make sure the read-ahead engine is notified
+                         * about this failure.
+                         */
+                        handle_ra_miss(mapping, &in->f_ra, index);
+
+                        /*
+                         * page didn't exist, allocate one.
                          */
                         page = page_cache_alloc_cold(mapping);
                         if (!page)
                                 break;
 
                         error = add_to_page_cache_lru(page, mapping, index,
-                                                mapping_gfp_mask(mapping));
+                                              mapping_gfp_mask(mapping));
                         if (unlikely(error)) {
                                 page_cache_release(page);
+                                if (error == -EEXIST)
+                                        continue;
                                 break;
                         }
-
-                        goto readpage;
+                        /*
+                         * add_to_page_cache() locks the page, unlock it
+                         * to avoid convoluting the logic below even more.
+                         */
+                        unlock_page(page);
                 }
 
+                pages[spd.nr_pages++] = page;
+                index++;
+        }
+
+        /*
+         * Now loop over the map and see if we need to start IO on any
+         * pages, fill in the partial map, etc.
+         */
+        index = *ppos >> PAGE_CACHE_SHIFT;
+        nr_pages = spd.nr_pages;
+        spd.nr_pages = 0;
+        for (page_nr = 0; page_nr < nr_pages; page_nr++) {
+                unsigned int this_len;
+
+                if (!len)
+                        break;
+
+                /*
+                 * this_len is the max we'll use from this page
+                 */
+                this_len = min_t(unsigned long, len, PAGE_CACHE_SIZE - loff);
+                page = pages[page_nr];
+
                 /*
                  * If the page isn't uptodate, we may need to start io on it
                  */
@@ -360,7 +378,6 @@ find_page:
                          */
                         if (!page->mapping) {
                                 unlock_page(page);
-                                page_cache_release(page);
                                 break;
                         }
                         /*
@@ -371,16 +388,20 @@ find_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);
+                                /*
+                                 * We really should re-lookup the page here,
+                                 * but it complicates things a lot. Instead
+                                 * lets just do what we already stored, and
+                                 * we'll get it the next time we are called.
+                                 */
                                 if (error == AOP_TRUNCATED_PAGE)
-                                        goto find_page;
+                                        error = 0;
+
                                 break;
                         }
 
@@ -389,10 +410,8 @@ readpage:
                          */
                         isize = i_size_read(mapping->host);
                         end_index = (isize - 1) >> PAGE_CACHE_SHIFT;
-                        if (unlikely(!isize || index > end_index)) {
-                                page_cache_release(page);
+                        if (unlikely(!isize || index > end_index))
                                 break;
-                        }
 
                         /*
                          * if this is the last page, see if we need to shrink
@@ -400,27 +419,33 @@ readpage:
                          */
                         if (end_index == index) {
                                 loff = PAGE_CACHE_SIZE - (isize & ~PAGE_CACHE_MASK);
-                                if (total_len + loff > isize) {
-                                        page_cache_release(page);
+                                if (total_len + loff > isize)
                                         break;
-                                }
                                 /*
                                  * force quit after adding this page
                                  */
-                                nr_pages = spd.nr_pages;
+                                len = this_len;
                                 this_len = min(this_len, loff);
                                 loff = 0;
                         }
                 }
 fill_it:
-                pages[spd.nr_pages] = page;
-                partial[spd.nr_pages].offset = loff;
-                partial[spd.nr_pages].len = this_len;
+                partial[page_nr].offset = loff;
+                partial[page_nr].len = this_len;
                 len -= this_len;
                 total_len += this_len;
                 loff = 0;
+                spd.nr_pages++;
+                index++;
         }
 
+        /*
+         * Release any pages at the end, if we quit early. 'i' is how far
+         * we got, 'nr_pages' is how many pages are in the map.
+         */
+        while (page_nr < nr_pages)
+                page_cache_release(pages[page_nr++]);
+
         if (spd.nr_pages)
                 return splice_to_pipe(pipe, &spd);
 
@@ -477,31 +502,21 @@ EXPORT_SYMBOL(generic_file_splice_read);
  * Send 'sd->len' bytes to socket from 'sd->file' at position 'sd->pos'
  * using sendpage(). Return the number of bytes sent.
  */
-static int pipe_to_sendpage(struct pipe_inode_info *info,
+static int pipe_to_sendpage(struct pipe_inode_info *pipe,
                             struct pipe_buffer *buf, struct splice_desc *sd)
 {
         struct file *file = sd->file;
         loff_t pos = sd->pos;
-        ssize_t ret;
-        void *ptr;
-        int more;
-
-        /*
-         * 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.
-         */
-        ptr = buf->ops->map(file, info, buf);
-        if (IS_ERR(ptr))
-                return PTR_ERR(ptr);
+        int ret, more;
 
-        more = (sd->flags & SPLICE_F_MORE) || sd->len < sd->total_len;
+        ret = buf->ops->pin(pipe, buf);
+        if (!ret) {
+                more = (sd->flags & SPLICE_F_MORE) || sd->len < sd->total_len;
 
-        ret = file->f_op->sendpage(file, buf->page, buf->offset, sd->len,
-                                   &pos, more);
+                ret = file->f_op->sendpage(file, buf->page, buf->offset,
+                                           sd->len, &pos, more);
+        }
 
-        buf->ops->unmap(info, buf);
         return ret;
 }
 
@@ -525,7 +540,7 @@ static int pipe_to_sendpage(struct pipe_inode_info *info,
  * 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,
+static int pipe_to_file(struct pipe_inode_info *pipe, struct pipe_buffer *buf,
                         struct splice_desc *sd)
 {
         struct file *file = sd->file;
@@ -534,15 +549,14 @@ static int pipe_to_file(struct pipe_inode_info *info, struct pipe_buffer *buf,
         unsigned int offset, this_len;
         struct page *page;
         pgoff_t index;
-        char *src;
         int ret;
 
         /*
          * make sure the data in this buffer is uptodate
          */
-        src = buf->ops->map(file, info, buf);
-        if (IS_ERR(src))
-                return PTR_ERR(src);
+        ret = buf->ops->pin(pipe, buf);
+        if (unlikely(ret))
+                return ret;
 
         index = sd->pos >> PAGE_CACHE_SHIFT;
         offset = sd->pos & ~PAGE_CACHE_MASK;
@@ -552,20 +566,25 @@ static int pipe_to_file(struct pipe_inode_info *info, struct pipe_buffer *buf,
                 this_len = PAGE_CACHE_SIZE - offset;
 
         /*
-         * Reuse buf page, if SPLICE_F_MOVE is set.
+         * Reuse buf page, if SPLICE_F_MOVE is set and we are doing a full
+         * page.
          */
-        if (sd->flags & SPLICE_F_MOVE) {
+        if ((sd->flags & SPLICE_F_MOVE) && this_len == PAGE_CACHE_SIZE) {
                 /*
-                 * 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 steal succeeds, buf->page is now pruned from the
+                 * pagecache and we can reuse it. The page will also be
+                 * locked on successful return.
                  */
-                if (buf->ops->steal(info, buf))
+                if (buf->ops->steal(pipe, 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_mask)) {
+                        unlock_page(page);
                         goto find_page;
+                }
+
+                page_cache_get(page);
 
                 if (!(buf->flags & PIPE_BUF_FLAG_LRU))
                         lru_cache_add(page);
@@ -619,40 +638,55 @@ find_page:
         }
 
         ret = mapping->a_ops->prepare_write(file, page, offset, offset+this_len);
-        if (ret == AOP_TRUNCATED_PAGE) {
+        if (unlikely(ret)) {
+                loff_t isize = i_size_read(mapping->host);
+
+                if (ret != AOP_TRUNCATED_PAGE)
+                        unlock_page(page);
                 page_cache_release(page);
-                goto find_page;
-        } else if (ret)
+                if (ret == AOP_TRUNCATED_PAGE)
+                        goto find_page;
+
+                /*
+                 * prepare_write() may have instantiated a few blocks
+                 * outside i_size.  Trim these off again.
+                 */
+                if (sd->pos + this_len > isize)
+                        vmtruncate(mapping->host, isize);
+
                 goto out;
+        }
 
-        if (!(buf->flags & PIPE_BUF_FLAG_STOLEN)) {
-                char *dst = kmap_atomic(page, KM_USER0);
+        if (buf->page != page) {
+                /*
+                 * Careful, ->map() uses KM_USER0!
+                 */
+                char *src = buf->ops->map(pipe, buf, 1);
+                char *dst = kmap_atomic(page, KM_USER1);
 
                 memcpy(dst + offset, src + buf->offset, this_len);
                 flush_dcache_page(page);
-                kunmap_atomic(dst, KM_USER0);
+                kunmap_atomic(dst, KM_USER1);
+                buf->ops->unmap(pipe, buf, src);
         }
 
         ret = mapping->a_ops->commit_write(file, page, offset, offset+this_len);
-        if (ret == AOP_TRUNCATED_PAGE) {
+        if (!ret) {
+                /*
+                 * Return the number of bytes written and mark page as
+                 * accessed, we are now done!
+                 */
+                ret = this_len;
+                mark_page_accessed(page);
+                balance_dirty_pages_ratelimited(mapping);
+        } else if (ret == AOP_TRUNCATED_PAGE) {
                 page_cache_release(page);
                 goto find_page;
-        } else if (ret)
-                goto out;
-
-        /*
-         * Return the number of bytes written.
-         */
-        ret = this_len;
-        mark_page_accessed(page);
-        balance_dirty_pages_ratelimited(mapping);
+        }
 out:
-        if (!(buf->flags & PIPE_BUF_FLAG_STOLEN))
-                page_cache_release(page);
-
+        page_cache_release(page);
         unlock_page(page);
 out_nomem:
-        buf->ops->unmap(info, buf);
         return ret;
 }
 
@@ -1060,7 +1094,7 @@ static long do_splice(struct file *in, loff_t __user *off_in,
  */
 static int get_iovec_page_array(const struct iovec __user *iov,
                                 unsigned int nr_vecs, struct page **pages,
-                                struct partial_page *partial)
+                                struct partial_page *partial, int aligned)
 {
         int buffers = 0, error = 0;
 
@@ -1100,6 +1134,15 @@ static int get_iovec_page_array(const struct iovec __user *iov,
                  * in the user pages.
                  */
                 off = (unsigned long) base & ~PAGE_MASK;
+
+                /*
+                 * If asked for alignment, the offset must be zero and the
+                 * length a multiple of the PAGE_SIZE.
+                 */
+                error = -EINVAL;
+                if (aligned && (off || len & ~PAGE_MASK))
+                        break;
+
                 npages = (off + len + PAGE_SIZE - 1) >> PAGE_SHIFT;
                 if (npages > PIPE_BUFFERS - buffers)
                         npages = PIPE_BUFFERS - buffers;
@@ -1115,7 +1158,7 @@ static int get_iovec_page_array(const struct iovec __user *iov,
                  * Fill this contiguous range into the partial page map.
                  */
                 for (i = 0; i < error; i++) {
-                        const int plen = min_t(size_t, len, PAGE_SIZE) - off;
+                        const int plen = min_t(size_t, len, PAGE_SIZE - off);
 
                         partial[buffers].offset = off;
                         partial[buffers].len = plen;
@@ -1193,7 +1236,8 @@ static long do_vmsplice(struct file *file, const struct iovec __user *iov,
         else if (unlikely(!nr_segs))
                 return 0;
 
-        spd.nr_pages = get_iovec_page_array(iov, nr_segs, pages, partial);
+        spd.nr_pages = get_iovec_page_array(iov, nr_segs, pages, partial,
+                                            flags & SPLICE_F_GIFT);
         if (spd.nr_pages <= 0)
                 return spd.nr_pages;
 
@@ -1301,6 +1345,12 @@ static int link_pipe(struct pipe_inode_info *ipipe,
                                 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;