1 files changed, 128 insertions, 256 deletions

diff --git a/fs/ext4/inode.c b/fs/ext4/inode.c
index 60a26f3a6f8b..f9c642b22efa 100644
--- a/fs/ext4/inode.c
+++ b/fs/ext4/inode.c
@@ -78,16 +78,14 @@ static int ext4_inode_is_fast_symlink(struct inode *inode)
  * but there may still be a record of it in the journal, and that record
  * still needs to be revoked.
  *
- * If the handle isn't valid we're not journaling so there's nothing to do.
+ * If the handle isn't valid we're not journaling, but we still need to
+ * call into ext4_journal_revoke() to put the buffer head.
  */
 int ext4_forget(handle_t *handle, int is_metadata, struct inode *inode,
                 struct buffer_head *bh, ext4_fsblk_t blocknr)
 {
         int err;
 
-        if (!ext4_handle_valid(handle))
-                return 0;
-
         might_sleep();
 
         BUFFER_TRACE(bh, "enter");
@@ -1513,14 +1511,14 @@ retry:
                  * Add inode to orphan list in case we crash before
                  * truncate finishes
                  */
-                if (pos + len > inode->i_size)
+                if (pos + len > inode->i_size && ext4_can_truncate(inode))
                         ext4_orphan_add(handle, inode);
 
                 ext4_journal_stop(handle);
                 if (pos + len > inode->i_size) {
-                        vmtruncate(inode, inode->i_size);
+                        ext4_truncate(inode);
                         /*
-                         * If vmtruncate failed early the inode might
+                         * If truncate failed early the inode might
                          * still be on the orphan list; we need to
                          * make sure the inode is removed from the
                          * orphan list in that case.
@@ -1614,7 +1612,7 @@ static int ext4_ordered_write_end(struct file *file,
                 ret2 = ext4_generic_write_end(file, mapping, pos, len, copied,
                                                         page, fsdata);
                 copied = ret2;
-                if (pos + len > inode->i_size)
+                if (pos + len > inode->i_size && ext4_can_truncate(inode))
                         /* if we have allocated more blocks and copied
                          * less. We will have blocks allocated outside
                          * inode->i_size. So truncate them
@@ -1628,9 +1626,9 @@ static int ext4_ordered_write_end(struct file *file,
                 ret = ret2;
 
         if (pos + len > inode->i_size) {
-                vmtruncate(inode, inode->i_size);
+                ext4_truncate(inode);
                 /*
-                 * If vmtruncate failed early the inode might still be
+                 * If truncate failed early the inode might still be
                  * on the orphan list; we need to make sure the inode
                  * is removed from the orphan list in that case.
                  */
@@ -1655,7 +1653,7 @@ static int ext4_writeback_write_end(struct file *file,
         ret2 = ext4_generic_write_end(file, mapping, pos, len, copied,
                                                         page, fsdata);
         copied = ret2;
-        if (pos + len > inode->i_size)
+        if (pos + len > inode->i_size && ext4_can_truncate(inode))
                 /* if we have allocated more blocks and copied
                  * less. We will have blocks allocated outside
                  * inode->i_size. So truncate them
@@ -1670,9 +1668,9 @@ static int ext4_writeback_write_end(struct file *file,
                 ret = ret2;
 
         if (pos + len > inode->i_size) {
-                vmtruncate(inode, inode->i_size);
+                ext4_truncate(inode);
                 /*
-                 * If vmtruncate failed early the inode might still be
+                 * If truncate failed early the inode might still be
                  * on the orphan list; we need to make sure the inode
                  * is removed from the orphan list in that case.
                  */
@@ -1722,7 +1720,7 @@ static int ext4_journalled_write_end(struct file *file,
 
         unlock_page(page);
         page_cache_release(page);
-        if (pos + len > inode->i_size)
+        if (pos + len > inode->i_size && ext4_can_truncate(inode))
                 /* if we have allocated more blocks and copied
                  * less. We will have blocks allocated outside
                  * inode->i_size. So truncate them
@@ -1733,9 +1731,9 @@ static int ext4_journalled_write_end(struct file *file,
         if (!ret)
                 ret = ret2;
         if (pos + len > inode->i_size) {
-                vmtruncate(inode, inode->i_size);
+                ext4_truncate(inode);
                 /*
-                 * If vmtruncate failed early the inode might still be
+                 * If truncate failed early the inode might still be
                  * on the orphan list; we need to make sure the inode
                  * is removed from the orphan list in that case.
                  */
@@ -2305,15 +2303,9 @@ flush_it:
         return;
 }
 
-static int ext4_bh_unmapped_or_delay(handle_t *handle, struct buffer_head *bh)
+static int ext4_bh_delay_or_unwritten(handle_t *handle, struct buffer_head *bh)
 {
-        /*
-         * unmapped buffer is possible for holes.
-         * delay buffer is possible with delayed allocation.
-         * We also need to consider unwritten buffer as unmapped.
-         */
-        return (!buffer_mapped(bh) || buffer_delay(bh) ||
-                                buffer_unwritten(bh)) && buffer_dirty(bh);
+        return (buffer_delay(bh) || buffer_unwritten(bh)) && buffer_dirty(bh);
 }
 
 /*
@@ -2398,9 +2390,9 @@ static int __mpage_da_writepage(struct page *page,
                          * We need to try to allocate
                          * unmapped blocks in the same page.
                          * Otherwise we won't make progress
-                         * with the page in ext4_da_writepage
+                         * with the page in ext4_writepage
                          */
-                        if (ext4_bh_unmapped_or_delay(NULL, bh)) {
+                        if (ext4_bh_delay_or_unwritten(NULL, bh)) {
                                 mpage_add_bh_to_extent(mpd, logical,
                                                        bh->b_size,
                                                        bh->b_state);
@@ -2517,7 +2509,6 @@ static int noalloc_get_block_write(struct inode *inode, sector_t iblock,
          * so call get_block_wrap with create = 0
          */
         ret = ext4_get_blocks(NULL, inode, iblock, max_blocks, bh_result, 0);
-        BUG_ON(create && ret == 0);
         if (ret > 0) {
                 bh_result->b_size = (ret << inode->i_blkbits);
                 ret = 0;
@@ -2525,15 +2516,102 @@ static int noalloc_get_block_write(struct inode *inode, sector_t iblock,
         return ret;
 }
 
+static int bget_one(handle_t *handle, struct buffer_head *bh)
+{
+        get_bh(bh);
+        return 0;
+}
+
+static int bput_one(handle_t *handle, struct buffer_head *bh)
+{
+        put_bh(bh);
+        return 0;
+}
+
+static int __ext4_journalled_writepage(struct page *page,
+                                       struct writeback_control *wbc,
+                                       unsigned int len)
+{
+        struct address_space *mapping = page->mapping;
+        struct inode *inode = mapping->host;
+        struct buffer_head *page_bufs;
+        handle_t *handle = NULL;
+        int ret = 0;
+        int err;
+
+        page_bufs = page_buffers(page);
+        BUG_ON(!page_bufs);
+        walk_page_buffers(handle, page_bufs, 0, len, NULL, bget_one);
+        /* As soon as we unlock the page, it can go away, but we have
+         * references to buffers so we are safe */
+        unlock_page(page);
+
+        handle = ext4_journal_start(inode, ext4_writepage_trans_blocks(inode));
+        if (IS_ERR(handle)) {
+                ret = PTR_ERR(handle);
+                goto out;
+        }
+
+        ret = walk_page_buffers(handle, page_bufs, 0, len, NULL,
+                                do_journal_get_write_access);
+
+        err = walk_page_buffers(handle, page_bufs, 0, len, NULL,
+                                write_end_fn);
+        if (ret == 0)
+                ret = err;
+        err = ext4_journal_stop(handle);
+        if (!ret)
+                ret = err;
+
+        walk_page_buffers(handle, page_bufs, 0, len, NULL, bput_one);
+        EXT4_I(inode)->i_state |= EXT4_STATE_JDATA;
+out:
+        return ret;
+}
+
 /*
+ * Note that we don't need to start a transaction unless we're journaling data
+ * because we should have holes filled from ext4_page_mkwrite(). We even don't
+ * need to file the inode to the transaction's list in ordered mode because if
+ * we are writing back data added by write(), the inode is already there and if
+ * we are writing back data modified via mmap(), noone guarantees in which
+ * transaction the data will hit the disk. In case we are journaling data, we
+ * cannot start transaction directly because transaction start ranks above page
+ * lock so we have to do some magic.
+ *
  * This function can get called via...
  *   - ext4_da_writepages after taking page lock (have journal handle)
  *   - journal_submit_inode_data_buffers (no journal handle)
  *   - shrink_page_list via pdflush (no journal handle)
  *   - grab_page_cache when doing write_begin (have journal handle)
+ *
+ * We don't do any block allocation in this function. If we have page with
+ * multiple blocks we need to write those buffer_heads that are mapped. This
+ * is important for mmaped based write. So if we do with blocksize 1K
+ * truncate(f, 1024);
+ * a = mmap(f, 0, 4096);
+ * a[0] = 'a';
+ * truncate(f, 4096);
+ * we have in the page first buffer_head mapped via page_mkwrite call back
+ * but other bufer_heads would be unmapped but dirty(dirty done via the
+ * do_wp_page). So writepage should write the first block. If we modify
+ * the mmap area beyond 1024 we will again get a page_fault and the
+ * page_mkwrite callback will do the block allocation and mark the
+ * buffer_heads mapped.
+ *
+ * We redirty the page if we have any buffer_heads that is either delay or
+ * unwritten in the page.
+ *
+ * We can get recursively called as show below.
+ *
+ *      ext4_writepage() -> kmalloc() -> __alloc_pages() -> page_launder() ->
+ *              ext4_writepage()
+ *
+ * But since we don't do any block allocation we should not deadlock.
+ * Page also have the dirty flag cleared so we don't get recurive page_lock.
  */
-static int ext4_da_writepage(struct page *page,
-                                struct writeback_control *wbc)
+static int ext4_writepage(struct page *page,
+                          struct writeback_control *wbc)
 {
         int ret = 0;
         loff_t size;
@@ -2541,7 +2619,7 @@ static int ext4_da_writepage(struct page *page,
         struct buffer_head *page_bufs;
         struct inode *inode = page->mapping->host;
 
-        trace_ext4_da_writepage(inode, page);
+        trace_ext4_writepage(inode, page);
         size = i_size_read(inode);
         if (page->index == size >> PAGE_CACHE_SHIFT)
                 len = size & ~PAGE_CACHE_MASK;
@@ -2551,7 +2629,7 @@ static int ext4_da_writepage(struct page *page,
         if (page_has_buffers(page)) {
                 page_bufs = page_buffers(page);
                 if (walk_page_buffers(NULL, page_bufs, 0, len, NULL,
-                                        ext4_bh_unmapped_or_delay)) {
+                                        ext4_bh_delay_or_unwritten)) {
                         /*
                          * We don't want to do  block allocation
                          * So redirty the page and return
@@ -2578,13 +2656,13 @@ static int ext4_da_writepage(struct page *page,
                  * all are mapped and non delay. We don't want to
                  * do block allocation here.
                  */
-                ret = block_prepare_write(page, 0, PAGE_CACHE_SIZE,
+                ret = block_prepare_write(page, 0, len,
                                           noalloc_get_block_write);
                 if (!ret) {
                         page_bufs = page_buffers(page);
                         /* check whether all are mapped and non delay */
                         if (walk_page_buffers(NULL, page_bufs, 0, len, NULL,
-                                                ext4_bh_unmapped_or_delay)) {
+                                                ext4_bh_delay_or_unwritten)) {
                                 redirty_page_for_writepage(wbc, page);
                                 unlock_page(page);
                                 return 0;
@@ -2600,7 +2678,16 @@ static int ext4_da_writepage(struct page *page,
                         return 0;
                 }
                 /* now mark the buffer_heads as dirty and uptodate */
-                block_commit_write(page, 0, PAGE_CACHE_SIZE);
+                block_commit_write(page, 0, len);
+        }
+
+        if (PageChecked(page) && ext4_should_journal_data(inode)) {
+                /*
+                 * It's mmapped pagecache.  Add buffers and journal it.  There
+                 * doesn't seem much point in redirtying the page here.
+                 */
+                ClearPageChecked(page);
+                return __ext4_journalled_writepage(page, wbc, len);
         }
 
         if (test_opt(inode->i_sb, NOBH) && ext4_should_writeback_data(inode))
@@ -2907,7 +2994,7 @@ retry:
                  * i_size_read because we hold i_mutex.
                  */
                 if (pos + len > inode->i_size)
-                        vmtruncate(inode, inode->i_size);
+                        ext4_truncate(inode);
         }
 
         if (ret == -ENOSPC && ext4_should_retry_alloc(inode->i_sb, &retries))
@@ -3130,222 +3217,6 @@ static sector_t ext4_bmap(struct address_space *mapping, sector_t block)
         return generic_block_bmap(mapping, block, ext4_get_block);
 }
 
-static int bget_one(handle_t *handle, struct buffer_head *bh)
-{
-        get_bh(bh);
-        return 0;
-}
-
-static int bput_one(handle_t *handle, struct buffer_head *bh)
-{
-        put_bh(bh);
-        return 0;
-}
-
-/*
- * Note that we don't need to start a transaction unless we're journaling data
- * because we should have holes filled from ext4_page_mkwrite(). We even don't
- * need to file the inode to the transaction's list in ordered mode because if
- * we are writing back data added by write(), the inode is already there and if
- * we are writing back data modified via mmap(), noone guarantees in which
- * transaction the data will hit the disk. In case we are journaling data, we
- * cannot start transaction directly because transaction start ranks above page
- * lock so we have to do some magic.
- *
- * In all journaling modes block_write_full_page() will start the I/O.
- *
- * Problem:
- *
- *      ext4_writepage() -> kmalloc() -> __alloc_pages() -> page_launder() ->
- *              ext4_writepage()
- *
- * Similar for:
- *
- *      ext4_file_write() -> generic_file_write() -> __alloc_pages() -> ...
- *
- * Same applies to ext4_get_block().  We will deadlock on various things like
- * lock_journal and i_data_sem
- *
- * Setting PF_MEMALLOC here doesn't work - too many internal memory
- * allocations fail.
- *
- * 16May01: If we're reentered then journal_current_handle() will be
- *          non-zero. We simply *return*.
- *
- * 1 July 2001: @@@ FIXME:
- *   In journalled data mode, a data buffer may be metadata against the
- *   current transaction.  But the same file is part of a shared mapping
- *   and someone does a writepage() on it.
- *
- *   We will move the buffer onto the async_data list, but *after* it has
- *   been dirtied. So there's a small window where we have dirty data on
- *   BJ_Metadata.
- *
- *   Note that this only applies to the last partial page in the file.  The
- *   bit which block_write_full_page() uses prepare/commit for.  (That's
- *   broken code anyway: it's wrong for msync()).
- *
- *   It's a rare case: affects the final partial page, for journalled data
- *   where the file is subject to bith write() and writepage() in the same
- *   transction.  To fix it we'll need a custom block_write_full_page().
- *   We'll probably need that anyway for journalling writepage() output.
- *
- * We don't honour synchronous mounts for writepage().  That would be
- * disastrous.  Any write() or metadata operation will sync the fs for
- * us.
- *
- */
-static int __ext4_normal_writepage(struct page *page,
-                                   struct writeback_control *wbc)
-{
-        struct inode *inode = page->mapping->host;
-
-        if (test_opt(inode->i_sb, NOBH))
-                return nobh_writepage(page, noalloc_get_block_write, wbc);
-        else
-                return block_write_full_page(page, noalloc_get_block_write,
-                                             wbc);
-}
-
-static int ext4_normal_writepage(struct page *page,
-                                 struct writeback_control *wbc)
-{
-        struct inode *inode = page->mapping->host;
-        loff_t size = i_size_read(inode);
-        loff_t len;
-
-        trace_ext4_normal_writepage(inode, page);
-        J_ASSERT(PageLocked(page));
-        if (page->index == size >> PAGE_CACHE_SHIFT)
-                len = size & ~PAGE_CACHE_MASK;
-        else
-                len = PAGE_CACHE_SIZE;
-
-        if (page_has_buffers(page)) {
-                /* if page has buffers it should all be mapped
-                 * and allocated. If there are not buffers attached
-                 * to the page we know the page is dirty but it lost
-                 * buffers. That means that at some moment in time
-                 * after write_begin() / write_end() has been called
-                 * all buffers have been clean and thus they must have been
-                 * written at least once. So they are all mapped and we can
-                 * happily proceed with mapping them and writing the page.
-                 */
-                BUG_ON(walk_page_buffers(NULL, page_buffers(page), 0, len, NULL,
-                                        ext4_bh_unmapped_or_delay));
-        }
-
-        if (!ext4_journal_current_handle())
-                return __ext4_normal_writepage(page, wbc);
-
-        redirty_page_for_writepage(wbc, page);
-        unlock_page(page);
-        return 0;
-}
-
-static int __ext4_journalled_writepage(struct page *page,
-                                       struct writeback_control *wbc)
-{
-        struct address_space *mapping = page->mapping;
-        struct inode *inode = mapping->host;
-        struct buffer_head *page_bufs;
-        handle_t *handle = NULL;
-        int ret = 0;
-        int err;
-
-        ret = block_prepare_write(page, 0, PAGE_CACHE_SIZE,
-                                  noalloc_get_block_write);
-        if (ret != 0)
-                goto out_unlock;
-
-        page_bufs = page_buffers(page);
-        walk_page_buffers(handle, page_bufs, 0, PAGE_CACHE_SIZE, NULL,
-                                                                bget_one);
-        /* As soon as we unlock the page, it can go away, but we have
-         * references to buffers so we are safe */
-        unlock_page(page);
-
-        handle = ext4_journal_start(inode, ext4_writepage_trans_blocks(inode));
-        if (IS_ERR(handle)) {
-                ret = PTR_ERR(handle);
-                goto out;
-        }
-
-        ret = walk_page_buffers(handle, page_bufs, 0,
-                        PAGE_CACHE_SIZE, NULL, do_journal_get_write_access);
-
-        err = walk_page_buffers(handle, page_bufs, 0,
-                                PAGE_CACHE_SIZE, NULL, write_end_fn);
-        if (ret == 0)
-                ret = err;
-        err = ext4_journal_stop(handle);
-        if (!ret)
-                ret = err;
-
-        walk_page_buffers(handle, page_bufs, 0,
-                                PAGE_CACHE_SIZE, NULL, bput_one);
-        EXT4_I(inode)->i_state |= EXT4_STATE_JDATA;
-        goto out;
-
-out_unlock:
-        unlock_page(page);
-out:
-        return ret;
-}
-
-static int ext4_journalled_writepage(struct page *page,
-                                     struct writeback_control *wbc)
-{
-        struct inode *inode = page->mapping->host;
-        loff_t size = i_size_read(inode);
-        loff_t len;
-
-        trace_ext4_journalled_writepage(inode, page);
-        J_ASSERT(PageLocked(page));
-        if (page->index == size >> PAGE_CACHE_SHIFT)
-                len = size & ~PAGE_CACHE_MASK;
-        else
-                len = PAGE_CACHE_SIZE;
-
-        if (page_has_buffers(page)) {
-                /* if page has buffers it should all be mapped
-                 * and allocated. If there are not buffers attached
-                 * to the page we know the page is dirty but it lost
-                 * buffers. That means that at some moment in time
-                 * after write_begin() / write_end() has been called
-                 * all buffers have been clean and thus they must have been
-                 * written at least once. So they are all mapped and we can
-                 * happily proceed with mapping them and writing the page.
-                 */
-                BUG_ON(walk_page_buffers(NULL, page_buffers(page), 0, len, NULL,
-                                        ext4_bh_unmapped_or_delay));
-        }
-
-        if (ext4_journal_current_handle())
-                goto no_write;
-
-        if (PageChecked(page)) {
-                /*
-                 * It's mmapped pagecache.  Add buffers and journal it.  There
-                 * doesn't seem much point in redirtying the page here.
-                 */
-                ClearPageChecked(page);
-                return __ext4_journalled_writepage(page, wbc);
-        } else {
-                /*
-                 * It may be a page full of checkpoint-mode buffers.  We don't
-                 * really know unless we go poke around in the buffer_heads.
-                 * But block_write_full_page will do the right thing.
-                 */
-                return block_write_full_page(page, noalloc_get_block_write,
-                                             wbc);
-        }
-no_write:
-        redirty_page_for_writepage(wbc, page);
-        unlock_page(page);
-        return 0;
-}
-
 static int ext4_readpage(struct file *file, struct page *page)
 {
         return mpage_readpage(page, ext4_get_block);
@@ -3492,7 +3363,7 @@ static int ext4_journalled_set_page_dirty(struct page *page)
 static const struct address_space_operations ext4_ordered_aops = {
         .readpage               = ext4_readpage,
         .readpages              = ext4_readpages,
-        .writepage              = ext4_normal_writepage,
+        .writepage              = ext4_writepage,
         .sync_page              = block_sync_page,
         .write_begin            = ext4_write_begin,
         .write_end              = ext4_ordered_write_end,
@@ -3507,7 +3378,7 @@ static const struct address_space_operations ext4_ordered_aops = {
 static const struct address_space_operations ext4_writeback_aops = {
         .readpage               = ext4_readpage,
         .readpages              = ext4_readpages,
-        .writepage              = ext4_normal_writepage,
+        .writepage              = ext4_writepage,
         .sync_page              = block_sync_page,
         .write_begin            = ext4_write_begin,
         .write_end              = ext4_writeback_write_end,
@@ -3522,7 +3393,7 @@ static const struct address_space_operations ext4_writeback_aops = {
 static const struct address_space_operations ext4_journalled_aops = {
         .readpage               = ext4_readpage,
         .readpages              = ext4_readpages,
-        .writepage              = ext4_journalled_writepage,
+        .writepage              = ext4_writepage,
         .sync_page              = block_sync_page,
         .write_begin            = ext4_write_begin,
         .write_end              = ext4_journalled_write_end,
@@ -3536,7 +3407,7 @@ static const struct address_space_operations ext4_journalled_aops = {
 static const struct address_space_operations ext4_da_aops = {
         .readpage               = ext4_readpage,
         .readpages              = ext4_readpages,
-        .writepage              = ext4_da_writepage,
+        .writepage              = ext4_writepage,
         .writepages             = ext4_da_writepages,
         .sync_page              = block_sync_page,
         .write_begin            = ext4_da_write_begin,
@@ -3583,7 +3454,8 @@ int ext4_block_truncate_page(handle_t *handle,
         struct page *page;
         int err = 0;
 
-        page = grab_cache_page(mapping, from >> PAGE_CACHE_SHIFT);
+        page = find_or_create_page(mapping, from >> PAGE_CACHE_SHIFT,
+                                   mapping_gfp_mask(mapping) & ~__GFP_FS);
         if (!page)
                 return -EINVAL;