introduce __block_write_begin

Split up the block_write_begin implementation - __block_write_begin is a new trivial wrapper for block_prepare_write that always takes an already allocated page and can be either called from block_write_begin or filesystem code that already has a page allocated. Remove the handling of already allocated pages from block_write_begin after switching all callers that do it to __block_write_begin. Signed-off-by: Christoph Hellwig <hch@lst.de> Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>

introduce __block_write_begin
Split up the block_write_begin implementation - __block_write_begin is a new trivial wrapper for block_prepare_write that always takes an already allocated page and can be either called from block_write_begin or filesystem code that already has a page allocated. Remove the handling of already allocated pages from block_write_begin after switching all callers that do it to __block_write_begin. Signed-off-by: Christoph Hellwig <hch@lst.de> Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
Christoph Hellwig · Al Viro
1 parent f4e420dc42
Showing 10 changed files with 39 additions and 64 deletions Side-by-side Diff
fs/buffer.c
fs/ext2/dir.c
fs/ext3/inode.c
fs/ext4/inode.c
fs/minix/inode.c
fs/nilfs2/dir.c
fs/reiserfs/inode.c
fs/sysv/itree.c
fs/ufs/inode.c
include/linux/buffer_head.h
@@ -1833,9 +1833,10 @@
 }
 EXPORT_SYMBOL(page_zero_new_buffers);
  
-static int __block_prepare_write(struct inode *inode, struct page *page,
-		unsigned from, unsigned to, get_block_t *get_block)
+int block_prepare_write(struct page *page, unsigned from, unsigned to,
+		get_block_t *get_block)
 {
+	struct inode *inode = page->mapping->host;
 	unsigned block_start, block_end;
 	sector_t block;
 	int err = 0;
  
  
@@ -1908,10 +1909,13 @@
 		if (!buffer_uptodate(*wait_bh))
 			err = -EIO;
 	}
-	if (unlikely(err))
+	if (unlikely(err)) {
 		page_zero_new_buffers(page, from, to);
+		ClearPageUptodate(page);
+	}
 	return err;
 }
+EXPORT_SYMBOL(block_prepare_write);
  
 static int __block_commit_write(struct inode *inode, struct page *page,
 		unsigned from, unsigned to)
@@ -1948,6 +1952,15 @@
 	return 0;
 }
  
+int __block_write_begin(struct page *page, loff_t pos, unsigned len,
+		get_block_t *get_block)
+{
+	unsigned start = pos & (PAGE_CACHE_SIZE - 1);
+
+	return block_prepare_write(page, start, start + len, get_block);
+}
+EXPORT_SYMBOL(__block_write_begin);
+
 /*
  * Filesystems implementing the new truncate sequence should use the
  * _newtrunc postfix variant which won't incorrectly call vmtruncate.
  
  
  
  
  
@@ -1958,41 +1971,22 @@
 			struct page **pagep, void **fsdata,
 			get_block_t *get_block)
 {
-	struct inode *inode = mapping->host;
-	int status = 0;
+	pgoff_t index = pos >> PAGE_CACHE_SHIFT;
 	struct page *page;
-	pgoff_t index;
-	unsigned start, end;
-	int ownpage = 0;
+	int status;
  
-	index = pos >> PAGE_CACHE_SHIFT;
-	start = pos & (PAGE_CACHE_SIZE - 1);
-	end = start + len;
+	page = grab_cache_page_write_begin(mapping, index, flags);
+	if (!page)
+		return -ENOMEM;
  
-	page = *pagep;
-	if (page == NULL) {
-		ownpage = 1;
-		page = grab_cache_page_write_begin(mapping, index, flags);
-		if (!page) {
-			status = -ENOMEM;
-			goto out;
-		}
-		*pagep = page;
-	} else
-		BUG_ON(!PageLocked(page));
-
-	status = __block_prepare_write(inode, page, start, end, get_block);
+	status = __block_write_begin(page, pos, len, get_block);
 	if (unlikely(status)) {
-		ClearPageUptodate(page);
-
-		if (ownpage) {
-			unlock_page(page);
-			page_cache_release(page);
-			*pagep = NULL;
-		}
+		unlock_page(page);
+		page_cache_release(page);
+		page = NULL;
 	}
  
-out:
+	*pagep = page;
 	return status;
 }
 EXPORT_SYMBOL(block_write_begin_newtrunc);
@@ -2378,17 +2372,6 @@
 	return err;
 }
 EXPORT_SYMBOL(cont_write_begin);
-
-int block_prepare_write(struct page *page, unsigned from, unsigned to,
-			get_block_t *get_block)
-{
-	struct inode *inode = page->mapping->host;
-	int err = __block_prepare_write(inode, page, from, to, get_block);
-	if (err)
-		ClearPageUptodate(page);
-	return err;
-}
-EXPORT_SYMBOL(block_prepare_write);
  
 int block_commit_write(struct page *page, unsigned from, unsigned to)
 {
@@ -450,8 +450,7 @@
  
 static int ext2_prepare_chunk(struct page *page, loff_t pos, unsigned len)
 {
-	return block_write_begin_newtrunc(NULL, page->mapping, pos, len, 0,
-					  &page, NULL, ext2_get_block);
+	return __block_write_begin(page, pos, len, ext2_get_block);
 }
  
 /* Releases the page */
@@ -1196,8 +1196,7 @@
 		ret = PTR_ERR(handle);
 		goto out;
 	}
-	ret = block_write_begin(file, mapping, pos, len, flags, pagep, fsdata,
-							ext3_get_block);
+	ret = __block_write_begin(page, pos, len, ext3_get_block);
 	if (ret)
 		goto write_begin_failed;
  
@@ -1578,11 +1578,9 @@
 	*pagep = page;
  
 	if (ext4_should_dioread_nolock(inode))
-		ret = block_write_begin(file, mapping, pos, len, flags, pagep,
-				fsdata, ext4_get_block_write);
+		ret = __block_write_begin(page, pos, len, ext4_get_block_write);
 	else
-		ret = block_write_begin(file, mapping, pos, len, flags, pagep,
-				fsdata, ext4_get_block);
+		ret = __block_write_begin(page, pos, len, ext4_get_block);
  
 	if (!ret && ext4_should_journal_data(inode)) {
 		ret = walk_page_buffers(handle, page_buffers(page),
@@ -1593,7 +1591,7 @@
 		unlock_page(page);
 		page_cache_release(page);
 		/*
-		 * block_write_begin may have instantiated a few blocks
+		 * __block_write_begin may have instantiated a few blocks
 		 * outside i_size.  Trim these off again. Don't need
 		 * i_size_read because we hold i_mutex.
 		 *
@@ -3185,8 +3183,7 @@
 	}
 	*pagep = page;
  
-	ret = block_write_begin(file, mapping, pos, len, flags, pagep, fsdata,
-				ext4_da_get_block_prep);
+	ret = __block_write_begin(page, pos, len, ext4_da_get_block_prep);
 	if (ret < 0) {
 		unlock_page(page);
 		ext4_journal_stop(handle);
@@ -359,8 +359,7 @@
  
 int minix_prepare_chunk(struct page *page, loff_t pos, unsigned len)
 {
-	return block_write_begin_newtrunc(NULL, page->mapping, pos, len, 0,
-					  &page, NULL, minix_get_block);
+	return __block_write_begin(page, pos, len, minix_get_block);
 }
  
 static int minix_write_begin(struct file *file, struct address_space *mapping,
@@ -83,8 +83,7 @@
 static int nilfs_prepare_chunk(struct page *page, unsigned from, unsigned to)
 {
 	loff_t pos = page_offset(page) + from;
-	return block_write_begin_newtrunc(NULL, page->mapping, pos, to - from,
-					  0, &page, NULL, nilfs_get_block);
+	return __block_write_begin(page, pos, to - from, nilfs_get_block);
 }
  
 static void nilfs_commit_chunk(struct page *page,
@@ -2585,8 +2585,7 @@
 		old_ref = th->t_refcount;
 		th->t_refcount++;
 	}
-	ret = block_write_begin(file, mapping, pos, len, flags, pagep, fsdata,
-				reiserfs_get_block);
+	ret = __block_write_begin(page, pos, len, reiserfs_get_block);
 	if (ret && reiserfs_transaction_running(inode->i_sb)) {
 		struct reiserfs_transaction_handle *th = current->journal_info;
 		/* this gets a little ugly.  If reiserfs_get_block returned an
@@ -461,8 +461,7 @@
  
 int sysv_prepare_chunk(struct page *page, loff_t pos, unsigned len)
 {
-	return block_write_begin_newtrunc(NULL, page->mapping, pos, len, 0,
-					  &page, NULL, get_block);
+	return __block_write_begin(page, pos, len, get_block);
 }
  
 static int sysv_write_begin(struct file *file, struct address_space *mapping,
@@ -560,8 +560,7 @@
  
 int ufs_prepare_chunk(struct page *page, loff_t pos, unsigned len)
 {
-	return block_write_begin_newtrunc(NULL, page->mapping, pos, len, 0,
-					  &page, NULL, ufs_getfrag_block);
+	return __block_write_begin(page, pos, len, ufs_getfrag_block);
 }
  
 static int ufs_write_begin(struct file *file, struct address_space *mapping,
@@ -209,6 +209,8 @@
 int block_write_begin(struct file *, struct address_space *,
 				loff_t, unsigned, unsigned,
 				struct page **, void **, get_block_t*);
+int __block_write_begin(struct page *page, loff_t pos, unsigned len,
+		get_block_t *get_block);
 int block_write_end(struct file *, struct address_space *,
 				loff_t, unsigned, unsigned,
 				struct page *, void *);
...	...	@@ -1833,9 +1833,10 @@
1833	1833	}
1834	1834	EXPORT_SYMBOL(page_zero_new_buffers);
1835	1835
1836		-static int __block_prepare_write(struct inode inode, struct page page,
1837		- unsigned from, unsigned to, get_block_t *get_block)
	1836	+int block_prepare_write(struct page *page, unsigned from, unsigned to,
	1837	+ get_block_t *get_block)
1838	1838	{
	1839	+ struct inode *inode = page->mapping->host;
1839	1840	unsigned block_start, block_end;
1840	1841	sector_t block;
1841	1842	int err = 0;
1842	1843
1843	1844
...	...	@@ -1908,10 +1909,13 @@
1908	1909	if (!buffer_uptodate(*wait_bh))
1909	1910	err = -EIO;
1910	1911	}
1911		- if (unlikely(err))
	1912	+ if (unlikely(err)) {
1912	1913	page_zero_new_buffers(page, from, to);
	1914	+ ClearPageUptodate(page);
	1915	+ }
1913	1916	return err;
1914	1917	}
	1918	+EXPORT_SYMBOL(block_prepare_write);
1915	1919
1916	1920	static int __block_commit_write(struct inode inode, struct page page,
1917	1921	unsigned from, unsigned to)
...	...	@@ -1948,6 +1952,15 @@
1948	1952	return 0;
1949	1953	}
1950	1954
	1955	+int __block_write_begin(struct page *page, loff_t pos, unsigned len,
	1956	+ get_block_t *get_block)
	1957	+{
	1958	+ unsigned start = pos & (PAGE_CACHE_SIZE - 1);
	1959	+
	1960	+ return block_prepare_write(page, start, start + len, get_block);
	1961	+}
	1962	+EXPORT_SYMBOL(__block_write_begin);
	1963	+
1951	1964	/*
1952	1965	* Filesystems implementing the new truncate sequence should use the
1953	1966	* _newtrunc postfix variant which won't incorrectly call vmtruncate.
1954	1967
1955	1968
1956	1969
1957	1970
1958	1971
...	...	@@ -1958,41 +1971,22 @@
1958	1971	struct page pagep, void fsdata,
1959	1972	get_block_t *get_block)
1960	1973	{
1961		- struct inode *inode = mapping->host;
1962		- int status = 0;
	1974	+ pgoff_t index = pos >> PAGE_CACHE_SHIFT;
1963	1975	struct page *page;
1964		- pgoff_t index;
1965		- unsigned start, end;
1966		- int ownpage = 0;
	1976	+ int status;
1967	1977
1968		- index = pos >> PAGE_CACHE_SHIFT;
1969		- start = pos & (PAGE_CACHE_SIZE - 1);
1970		- end = start + len;
	1978	+ page = grab_cache_page_write_begin(mapping, index, flags);
	1979	+ if (!page)
	1980	+ return -ENOMEM;
1971	1981
1972		- page = *pagep;
1973		- if (page == NULL) {
1974		- ownpage = 1;
1975		- page = grab_cache_page_write_begin(mapping, index, flags);
1976		- if (!page) {
1977		- status = -ENOMEM;
1978		- goto out;
1979		- }
1980		- *pagep = page;
1981		- } else
1982		- BUG_ON(!PageLocked(page));
1983		-
1984		- status = __block_prepare_write(inode, page, start, end, get_block);
	1982	+ status = __block_write_begin(page, pos, len, get_block);
1985	1983	if (unlikely(status)) {
1986		- ClearPageUptodate(page);
1987		-
1988		- if (ownpage) {
1989		- unlock_page(page);
1990		- page_cache_release(page);
1991		- *pagep = NULL;
1992		- }
	1984	+ unlock_page(page);
	1985	+ page_cache_release(page);
	1986	+ page = NULL;
1993	1987	}
1994	1988
1995		-out:
	1989	+ *pagep = page;
1996	1990	return status;
1997	1991	}
1998	1992	EXPORT_SYMBOL(block_write_begin_newtrunc);
...	...	@@ -2378,17 +2372,6 @@
2378	2372	return err;
2379	2373	}
2380	2374	EXPORT_SYMBOL(cont_write_begin);
2381		-
2382		-int block_prepare_write(struct page *page, unsigned from, unsigned to,
2383		- get_block_t *get_block)
2384		-{
2385		- struct inode *inode = page->mapping->host;
2386		- int err = __block_prepare_write(inode, page, from, to, get_block);
2387		- if (err)
2388		- ClearPageUptodate(page);
2389		- return err;
2390		-}
2391		-EXPORT_SYMBOL(block_prepare_write);
2392	2375
2393	2376	int block_commit_write(struct page *page, unsigned from, unsigned to)
2394	2377	{
...	...	@@ -450,8 +450,7 @@
450	450
451	451	static int ext2_prepare_chunk(struct page *page, loff_t pos, unsigned len)
452	452	{
453		- return block_write_begin_newtrunc(NULL, page->mapping, pos, len, 0,
454		- &page, NULL, ext2_get_block);
	453	+ return __block_write_begin(page, pos, len, ext2_get_block);
455	454	}
456	455
457	456	/* Releases the page */
...	...	@@ -1196,8 +1196,7 @@
1196	1196	ret = PTR_ERR(handle);
1197	1197	goto out;
1198	1198	}
1199		- ret = block_write_begin(file, mapping, pos, len, flags, pagep, fsdata,
1200		- ext3_get_block);
	1199	+ ret = __block_write_begin(page, pos, len, ext3_get_block);
1201	1200	if (ret)
1202	1201	goto write_begin_failed;
1203	1202
...	...	@@ -1578,11 +1578,9 @@
1578	1578	*pagep = page;
1579	1579
1580	1580	if (ext4_should_dioread_nolock(inode))
1581		- ret = block_write_begin(file, mapping, pos, len, flags, pagep,
1582		- fsdata, ext4_get_block_write);
	1581	+ ret = __block_write_begin(page, pos, len, ext4_get_block_write);
1583	1582	else
1584		- ret = block_write_begin(file, mapping, pos, len, flags, pagep,
1585		- fsdata, ext4_get_block);
	1583	+ ret = __block_write_begin(page, pos, len, ext4_get_block);
1586	1584
1587	1585	if (!ret && ext4_should_journal_data(inode)) {
1588	1586	ret = walk_page_buffers(handle, page_buffers(page),
...	...	@@ -1593,7 +1591,7 @@
1593	1591	unlock_page(page);
1594	1592	page_cache_release(page);
1595	1593	/*
1596		- * block_write_begin may have instantiated a few blocks
	1594	+ * __block_write_begin may have instantiated a few blocks
1597	1595	* outside i_size. Trim these off again. Don't need
1598	1596	* i_size_read because we hold i_mutex.
1599	1597	*
...	...	@@ -3185,8 +3183,7 @@
3185	3183	}
3186	3184	*pagep = page;
3187	3185
3188		- ret = block_write_begin(file, mapping, pos, len, flags, pagep, fsdata,
3189		- ext4_da_get_block_prep);
	3186	+ ret = __block_write_begin(page, pos, len, ext4_da_get_block_prep);
3190	3187	if (ret < 0) {
3191	3188	unlock_page(page);
3192	3189	ext4_journal_stop(handle);
...	...	@@ -359,8 +359,7 @@
359	359
360	360	int minix_prepare_chunk(struct page *page, loff_t pos, unsigned len)
361	361	{
362		- return block_write_begin_newtrunc(NULL, page->mapping, pos, len, 0,
363		- &page, NULL, minix_get_block);
	362	+ return __block_write_begin(page, pos, len, minix_get_block);
364	363	}
365	364
366	365	static int minix_write_begin(struct file file, struct address_space mapping,
...	...	@@ -83,8 +83,7 @@
83	83	static int nilfs_prepare_chunk(struct page *page, unsigned from, unsigned to)
84	84	{
85	85	loff_t pos = page_offset(page) + from;
86		- return block_write_begin_newtrunc(NULL, page->mapping, pos, to - from,
87		- 0, &page, NULL, nilfs_get_block);
	86	+ return __block_write_begin(page, pos, to - from, nilfs_get_block);
88	87	}
89	88
90	89	static void nilfs_commit_chunk(struct page *page,
...	...	@@ -2585,8 +2585,7 @@
2585	2585	old_ref = th->t_refcount;
2586	2586	th->t_refcount++;
2587	2587	}
2588		- ret = block_write_begin(file, mapping, pos, len, flags, pagep, fsdata,
2589		- reiserfs_get_block);
	2588	+ ret = __block_write_begin(page, pos, len, reiserfs_get_block);
2590	2589	if (ret && reiserfs_transaction_running(inode->i_sb)) {
2591	2590	struct reiserfs_transaction_handle *th = current->journal_info;
2592	2591	/* this gets a little ugly. If reiserfs_get_block returned an
...	...	@@ -461,8 +461,7 @@
461	461
462	462	int sysv_prepare_chunk(struct page *page, loff_t pos, unsigned len)
463	463	{
464		- return block_write_begin_newtrunc(NULL, page->mapping, pos, len, 0,
465		- &page, NULL, get_block);
	464	+ return __block_write_begin(page, pos, len, get_block);
466	465	}
467	466
468	467	static int sysv_write_begin(struct file file, struct address_space mapping,
...	...	@@ -560,8 +560,7 @@
560	560
561	561	int ufs_prepare_chunk(struct page *page, loff_t pos, unsigned len)
562	562	{
563		- return block_write_begin_newtrunc(NULL, page->mapping, pos, len, 0,
564		- &page, NULL, ufs_getfrag_block);
	563	+ return __block_write_begin(page, pos, len, ufs_getfrag_block);
565	564	}
566	565
567	566	static int ufs_write_begin(struct file file, struct address_space mapping,
...	...	@@ -209,6 +209,8 @@
209	209	int block_write_begin(struct file , struct address_space ,
210	210	loff_t, unsigned, unsigned,
211	211	struct page , void , get_block_t*);
	212	+int __block_write_begin(struct page *page, loff_t pos, unsigned len,
	213	+ get_block_t *get_block);
212	214	int block_write_end(struct file , struct address_space ,
213	215	loff_t, unsigned, unsigned,
214	216	struct page , void );