* 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");
* 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.
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
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.
*/
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
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.
*/
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
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.
*/
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);
}
/*
* 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);
* 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;
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;
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;
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
* 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;
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))
* 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))
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);
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,
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,
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,
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,
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;
git.openpandora.org / pandora-kernel.git / blobdiff