NTFS: 2.0.12 - Initial cleanup of address space operations following 2.0.11 changes.

- Merge fs/ntfs/aops.c::end_buffer_read_mst_async() and
  fs/ntfs/aops.c::end_buffer_read_file_async() into one function
  fs/ntfs/aops.c::end_buffer_read_attr_async() using NInoMstProtected()
  to determine whether to apply mst fixups or not.
- Above change allows merging fs/ntfs/aops.c::ntfs_file_read_block()
  and fs/ntfs/aops.c::ntfs_mst_readpage() into one function
  fs/ntfs/aops.c::ntfs_attr_read_block(). Also, create a tiny wrapper
  fs/ntfs/aops.c::ntfs_mst_readpage() to transform the parameters from
  the VFS readpage function prototype to the ntfs_attr_read_block()
  function prototype.

Documentation/filesystems/ntfs.txt

@@ -247,6 +247,9 @@ ChangeLog
 
 Note, a technical ChangeLog aimed at kernel hackers is in fs/ntfs/ChangeLog.
 
+2.0.12:
+	- Internal cleanups in address space operations made possible by the
+	  changes introduced in the previous release.
 2.0.11:
 	- Internal updates and cleanups introducing the first step towards
 	  fake inode based attribute i/o.

fs/ntfs/ChangeLog

@@ -6,7 +6,7 @@ ToDo:
 	  user open()s a file with i_size > s_maxbytes? Should read_inode()
 	  truncate the visible i_size? Will the user just get -E2BIG (or
 	  whatever) on open()? Or will (s)he be able to open() but lseek() and
-	  read() will fail when s_maxbytes is reached? -> Investigate this!
+	  read() will fail when s_maxbytes is reached? -> Investigate this.
 	- Implement/allow non-resident index bitmaps in dir.c::ntfs_readdir()
 	  and then also consider initialized_size w.r.t. the bitmaps, etc.
 	- vcn_to_lcn() should somehow return the correct pointer within the
@@ -17,14 +17,28 @@ ToDo:
 	- Consider if ntfs_file_read_compressed_block() shouldn't be coping
 	  with initialized_size < data_size. I don't think it can happen but
 	  it requires more careful consideration.
-	- CLEANUP: Modularise and reuse code in aops.c. At the moment we have
-	  several copies of almost identicall functions and the functions are
-	  quite big. Modularising them a bit, e.g. a-la get_block(), will make
-	  them cleaner and make code reuse easier.
+	- CLEANUP: At the moment we have two copies of almost identical
+	  functions in aops.c, can merge them once fake inode address space
+	  based attribute i/o is further developed.
+	- CLEANUP: Modularising code in aops.c a bit, e.g. a-la get_block(),
+	  will be cleaner and make code reuse easier.
 	- Enable NFS exporting of NTFS.
 	- Use iget5_locked() and friends instead of conventional iget().
 	- Use fake inodes for address space i/o.
 
+2.0.12 - Initial cleanup of address space operations following 2.0.11 changes.
+
+	- Merge fs/ntfs/aops.c::end_buffer_read_mst_async() and
+	  fs/ntfs/aops.c::end_buffer_read_file_async() into one function
+	  fs/ntfs/aops.c::end_buffer_read_attr_async() using NInoMstProtected()
+	  to determine whether to apply mst fixups or not.
+	- Above change allows merging fs/ntfs/aops.c::ntfs_file_read_block()
+	  and fs/ntfs/aops.c::ntfs_mst_readpage() into one function
+	  fs/ntfs/aops.c::ntfs_attr_read_block(). Also, create a tiny wrapper
+	  fs/ntfs/aops.c::ntfs_mst_readpage() to transform the parameters from
+	  the VFS readpage function prototype to the ntfs_attr_read_block()
+	  function prototype.
+
 2.0.11 - Initial preparations for fake inode based attribute i/o.
 
 	- Move definition of ntfs_inode_state_bits to fs/ntfs/inode.h and

fs/ntfs/Makefile

@@ -5,7 +5,7 @@ obj-$(CONFIG_NTFS_FS) += ntfs.o
 ntfs-objs := aops.o attrib.o compress.o debug.o dir.o file.o inode.o mft.o \
 	     mst.o namei.o super.o sysctl.o time.o unistr.o upcase.o
 
-EXTRA_CFLAGS = -DNTFS_VERSION=\"2.0.11\"
+EXTRA_CFLAGS = -DNTFS_VERSION=\"2.0.12\"
 
 ifeq ($(CONFIG_NTFS_DEBUG),y)
 EXTRA_CFLAGS += -DDEBUG

fs/ntfs/aops.c

@@ -3,7 +3,7 @@
  * 	    Part of the Linux-NTFS project.
  *
  * Copyright (c) 2001,2002 Anton Altaparmakov.
- * Copyright (C) 2002 Richard Russon.
+ * Copyright (c) 2002 Richard Russon.
  *
  * This program/include file is free software; you can redistribute it and/or
  * modify it under the terms of the GNU General Public License as published
@@ -30,31 +30,43 @@
 #include "ntfs.h"
 
 /**
- * end_buffer_read_file_async -
+ * end_buffer_read_attr_async - async io completion for reading attributes
+ * @bh:		buffer head on which io is completed
+ * @uptodate:	whether @bh is now uptodate or not
  *
- * Async io completion handler for accessing files. Adapted from
- * end_buffer_read_mst_async().
+ * Asynchronous I/O completion handler for reading pages belonging to the
+ * attribute address space of an inode. The inodes can either be files or
+ * directories or they can be fake inodes describing some attribute.
+ *
+ * If NInoMstProtected(), perform the post read mst fixups when all IO on the
+ * page has been completed and mark the page uptodate or set the error bit on
+ * the page. To determine the size of the records that need fixing up, we cheat
+ * a little bit by setting the index_block_size in ntfs_inode to the ntfs
+ * record size, and index_block_size_bits, to the log(base 2) of the ntfs
+ * record size.
  */
-static void end_buffer_read_file_async(struct buffer_head *bh, int uptodate)
+static void end_buffer_read_attr_async(struct buffer_head *bh, int uptodate)
 {
 	static spinlock_t page_uptodate_lock = SPIN_LOCK_UNLOCKED;
 	unsigned long flags;
 	struct buffer_head *tmp;
 	struct page *page;
+	ntfs_inode *ni;
 
-	if (uptodate)
+	if (likely(uptodate))
 		set_buffer_uptodate(bh);
 	else
 		clear_buffer_uptodate(bh);
 
 	page = bh->b_page;
 
+	ni = NTFS_I(page->mapping->host);
+
 	if (likely(uptodate)) {
 		s64 file_ofs;
 
-		ntfs_inode *ni = NTFS_I(page->mapping->host);
-
 		file_ofs = (page->index << PAGE_CACHE_SHIFT) + bh_offset(bh);
+		/* Check for the current buffer head overflowing. */
 		if (file_ofs + bh->b_size > ni->initialized_size) {
 			char *addr;
 			int ofs = 0;
@@ -82,10 +94,47 @@ static void end_buffer_read_file_async(struct buffer_head *bh, int uptodate)
 			SetPageError(page);
 		tmp = tmp->b_this_page;
 	}
-
 	spin_unlock_irqrestore(&page_uptodate_lock, flags);
-	if (!PageError(page))
+	/*
+	 * If none of the buffers had errors then we can set the page uptodate,
+	 * but we first have to perform the post read mst fixups, if the
+	 * attribute is mst protected, i.e. if NInoMstProteced(ni) is true.
+	 */
+	if (!NInoMstProtected(ni)) {
+		if (likely(!PageError(page)))
+			SetPageUptodate(page);
+		unlock_page(page);
+		return;
+	} else {
+		char *addr;
+		unsigned int i, recs, nr_err;
+		u32 rec_size;
+
+		rec_size = ni->_IDM(index_block_size);
+		recs = PAGE_CACHE_SIZE / rec_size;
+		addr = kmap_atomic(page, KM_BIO_SRC_IRQ);
+		for (i = nr_err = 0; i < recs; i++) {
+			if (likely(!post_read_mst_fixup((NTFS_RECORD*)(addr +
+					i * rec_size), rec_size)))
+				continue;
+			nr_err++;
+			ntfs_error(ni->vol->sb, "post_read_mst_fixup() failed, "
+					"corrupt %s record 0x%Lx. Run chkdsk.",
+					ni->mft_no ? "index" : "mft",
+					(long long)(((s64)page->index <<
+					PAGE_CACHE_SHIFT >>
+					ni->_IDM(index_block_size_bits)) + i));
+		}
+		flush_dcache_page(page);
+		kunmap_atomic(addr, KM_BIO_SRC_IRQ);
+		if (likely(!nr_err && recs))
 			SetPageUptodate(page);
+		else {
+			ntfs_error(ni->vol->sb, "Setting page error, index "
+					"0x%lx.", page->index);
+			SetPageError(page);
+		}
+	}
 	unlock_page(page);
 	return;
 still_busy:
@@ -94,11 +143,20 @@ static void end_buffer_read_file_async(struct buffer_head *bh, int uptodate)
 }
 
 /**
- * ntfs_file_read_block -
+ * ntfs_attr_read_block - fill a @page of an address space with data
+ * @page:	page cache page to fill with data
  *
- * NTFS version of block_read_full_page(). Adapted from ntfs_mst_readpage().
+ * Fill the page @page of the address space belonging to the @page->host inode.
+ * We read each buffer asynchronously and when all buffers are read in, our io
+ * completion handler end_buffer_read_attr_async(), if required, automatically
+ * applies the mst fixups to the page before finally marking it uptodate and
+ * unlocking it.
+ *
+ * Return 0 on success and -errno on error.
+ *
+ * Contains an adapted version of fs/buffer.c::block_read_full_page().
  */
-static int ntfs_file_read_block(struct page *page)
+static int ntfs_attr_read_block(struct page *page)
 {
 	VCN vcn;
 	LCN lcn;
@@ -119,7 +177,7 @@ static int ntfs_file_read_block(struct page *page)
 	if (!page_has_buffers(page))
 		create_empty_buffers(page, blocksize, 0);
 	bh = head = page_buffers(page);
-	if (!bh)
+	if (unlikely(!bh))
 		return -ENOMEM;
 
 	blocks = PAGE_CACHE_SIZE >> blocksize_bits;
@@ -128,11 +186,9 @@ static int ntfs_file_read_block(struct page *page)
 	zblock = (ni->initialized_size + blocksize - 1) >> blocksize_bits;
 
 #ifdef DEBUG
-	if (unlikely(!ni->mft_no)) {
-		ntfs_error(vol->sb, "NTFS: Attempt to access $MFT! This is a "
-				"very serious bug! Denying access...");
-		return -EACCES;
-	}
+	if (unlikely(!ni->run_list.rl && !ni->mft_no))
+		panic("NTFS: $MFT/$DATA run list has been unmapped! This is a "
+				"very serious bug! Cannot continue...");
 #endif
 
 	/* Loop through all the buffers in the page. */
@@ -211,7 +267,7 @@ static int ntfs_file_read_block(struct page *page)
 		for (i = 0; i < nr; i++) {
 			struct buffer_head *tbh = arr[i];
 			lock_buffer(tbh);
-			tbh->b_end_io = end_buffer_read_file_async;
+			tbh->b_end_io = end_buffer_read_attr_async;
 			set_buffer_async_read(tbh);
 		}
 		/* Finally, start i/o on the buffers. */
@@ -220,7 +276,7 @@ static int ntfs_file_read_block(struct page *page)
 		return 0;
 	}
 	/* No i/o was scheduled on any of the buffers. */
-	if (!PageError(page))
+	if (likely(!PageError(page)))
 		SetPageUptodate(page);
 	else /* Signal synchronous i/o error. */
 		nr = -EIO;
@@ -234,17 +290,17 @@ static int ntfs_file_read_block(struct page *page)
  * @page:	page cache page to fill with data
  *
  * For non-resident attributes, ntfs_file_readpage() fills the @page of the open
- * file @file by calling the generic block_read_full_page() function provided by
- * the kernel which in turn invokes our ntfs_file_get_block() callback in order
- * to create and read in the buffers associated with the page asynchronously.
+ * file @file by calling the ntfs version of the generic block_read_full_page()
+ * function provided by the kernel, ntfs_attr_read_block(), which in turn
+ * creates and reads in the buffers associated with the page asynchronously.
  *
  * For resident attributes, OTOH, ntfs_file_readpage() fills @page by copying
  * the data from the mft record (which at this stage is most likely in memory)
- * and fills the remainder with zeroes. Thus, in this case I/O is synchronous,
+ * and fills the remainder with zeroes. Thus, in this case, I/O is synchronous,
  * as even if the mft record is not cached at this point in time, we need to
  * wait for it to be read in before we can do the copy.
  *
- * Return zero on success or -errno on error.
+ * Return 0 on success or -errno on error.
  */
 static int ntfs_file_readpage(struct file *file, struct page *page)
 {
@@ -256,43 +312,43 @@ static int ntfs_file_readpage(struct file *file, struct page *page)
 	u32 attr_len;
 	int err = 0;
 
-	if (!PageLocked(page))
+	if (unlikely(!PageLocked(page)))
 		PAGE_BUG(page);
 
 	ni = NTFS_I(page->mapping->host);
 
 	/* Is the unnamed $DATA attribute resident? */
-	if (test_bit(NI_NonResident, &ni->state)) {
+	if (NInoNonResident(ni)) {
 		/* Attribute is not resident. */
 
 		/* If the file is encrypted, we deny access, just like NT4. */
-		if (test_bit(NI_Encrypted, &ni->state)) {
+		if (NInoEncrypted(ni)) {
 			err = -EACCES;
 			goto unl_err_out;
 		}
 		/* Compressed data stream. Handled in compress.c. */
-		if (test_bit(NI_Compressed, &ni->state))
+		if (NInoCompressed(ni))
 			return ntfs_file_read_compressed_block(page);
 		/* Normal data stream. */
-		return ntfs_file_read_block(page);
+		return ntfs_attr_read_block(page);
 	}
 	/* Attribute is resident, implying it is not compressed or encrypted. */
 
 	/* Map, pin and lock the mft record for reading. */
 	mrec = map_mft_record(READ, ni);
-	if (IS_ERR(mrec)) {
+	if (unlikely(IS_ERR(mrec))) {
 		err = PTR_ERR(mrec);
 		goto unl_err_out;
 	}
 
 	ctx = get_attr_search_ctx(ni, mrec);
-	if (!ctx) {
+	if (unlikely(!ctx)) {
 		err = -ENOMEM;
 		goto unm_unl_err_out;
 	}
 
 	/* Find the data attribute in the mft record. */
-	if (!lookup_attr(AT_DATA, NULL, 0, 0, 0, NULL, 0, ctx)) {
+	if (unlikely(!lookup_attr(AT_DATA, NULL, 0, 0, 0, NULL, 0, ctx))) {
 		err = -ENOENT;
 		goto put_unm_unl_err_out;
 	}
@@ -330,6 +386,25 @@ static int ntfs_file_readpage(struct file *file, struct page *page)
 	return err;
 }
 
+/**
+ * ntfs_mst_readpage - fill a @page of the mft or a directory with data
+ * @file:	open file/directory to which the @page belongs or NULL
+ * @page:	page cache page to fill with data
+ *
+ * Readpage method for the VFS address space operations of directory inodes
+ * and the $MFT/$DATA attribute.
+ *
+ * We just call ntfs_attr_read_block() here, in fact we only need this wrapper
+ * because of the difference in function parameters.
+ */
+int ntfs_mst_readpage(struct file *file, struct page *page)
+{
+	if (unlikely(!PageLocked(page)))
+		PAGE_BUG(page);
+
+	return ntfs_attr_read_block(page);
+}
+
 /**
  * end_buffer_read_mftbmp_async -
  *
@@ -343,7 +418,7 @@ static void end_buffer_read_mftbmp_async(struct buffer_head *bh, int uptodate)
 	struct buffer_head *tmp;
 	struct page *page;
 
-	if (uptodate)
+	if (likely(uptodate))
 		set_buffer_uptodate(bh);
 	else
 		clear_buffer_uptodate(bh);
@@ -386,7 +461,7 @@ static void end_buffer_read_mftbmp_async(struct buffer_head *bh, int uptodate)
 	}
 
 	spin_unlock_irqrestore(&page_uptodate_lock, flags);
-	if (!PageError(page))
+	if (likely(!PageError(page)))
 		SetPageUptodate(page);
 	unlock_page(page);
 	return;
@@ -410,7 +485,7 @@ static int ntfs_mftbmp_readpage(ntfs_volume *vol, struct page *page)
 	int nr, i;
 	unsigned char blocksize_bits;
 
-	if (!PageLocked(page))
+	if (unlikely(!PageLocked(page)))
 		PAGE_BUG(page);
 
 	blocksize = vol->sb->s_blocksize;
@@ -419,7 +494,7 @@ static int ntfs_mftbmp_readpage(ntfs_volume *vol, struct page *page)
 	if (!page_has_buffers(page))
 		create_empty_buffers(page, blocksize, 0);
 	bh = head = page_buffers(page);
-	if (!bh)
+	if (unlikely(!bh))
 		return -ENOMEM;
 
 	blocks = PAGE_CACHE_SIZE >> blocksize_bits;
@@ -503,264 +578,7 @@ static int ntfs_mftbmp_readpage(ntfs_volume *vol, struct page *page)
 		return 0;
 	}
 	/* No i/o was scheduled on any of the buffers. */
-	if (!PageError(page))
-		SetPageUptodate(page);
-	else /* Signal synchronous i/o error. */
-		nr = -EIO;
-	unlock_page(page);
-	return nr;
-}
-
-/**
- * end_buffer_read_mst_async - async io completion for reading index records
- * @bh:		buffer head on which io is completed
- * @uptodate:	whether @bh is now uptodate or not
- *
- * Asynchronous I/O completion handler for reading pages belonging to the
- * index allocation attribute address space of directory inodes.
- *
- * Perform the post read mst fixups when all IO on the page has been completed
- * and marks the page uptodate or sets the error bit on the page.
- *
- * Adapted from fs/buffer.c.
- *
- * NOTE: We use this function as async io completion handler for reading pages
- * belonging to the mft data attribute address space, too as this saves
- * duplicating an almost identical function. We do this by cheating a little
- * bit in setting the index_block_size in the mft ntfs_inode to the mft record
- * size of the volume (vol->mft_record_size), and index_block_size_bits to
- * mft_record_size_bits, respectively.
- */
-static void end_buffer_read_mst_async(struct buffer_head *bh, int uptodate)
-{
-	static spinlock_t page_uptodate_lock = SPIN_LOCK_UNLOCKED;
-	unsigned long flags;
-	struct buffer_head *tmp;
-	struct page *page;
-	ntfs_inode *ni;
-
-	if (uptodate)
-		set_buffer_uptodate(bh);
-	else
-		clear_buffer_uptodate(bh);
-
-	page = bh->b_page;
-
-	ni = NTFS_I(page->mapping->host);
-
-	if (likely(uptodate)) {
-		s64 file_ofs;
-
-		file_ofs = (page->index << PAGE_CACHE_SHIFT) + bh_offset(bh);
-		/* Check for the current buffer head overflowing. */
-		if (file_ofs + bh->b_size > ni->initialized_size) {
-			char *addr;
-			int ofs = 0;
-
-			if (file_ofs < ni->initialized_size)
-				ofs = ni->initialized_size - file_ofs;
-			addr = kmap_atomic(page, KM_BIO_SRC_IRQ);
-			memset(addr + bh_offset(bh) + ofs, 0, bh->b_size - ofs);
-			flush_dcache_page(page);
-			kunmap_atomic(addr, KM_BIO_SRC_IRQ);
-		}
-	} else
-		SetPageError(page);
-
-	spin_lock_irqsave(&page_uptodate_lock, flags);
-	clear_buffer_async_read(bh);
-	unlock_buffer(bh);
-
-	tmp = bh->b_this_page;
-	while (tmp != bh) {
-		if (buffer_locked(tmp)) {
-			if (buffer_async_read(tmp))
-				goto still_busy;
-		} else if (!buffer_uptodate(tmp))
-			SetPageError(page);
-		tmp = tmp->b_this_page;
-	}
-
-	spin_unlock_irqrestore(&page_uptodate_lock, flags);
-	/*
-	 * If none of the buffers had errors then we can set the page uptodate,
-	 * but we first have to perform the post read mst fixups.
-	 */
-	if (!PageError(page)) {
-		char *addr;
-		unsigned int i, recs, nr_err = 0;
-		u32 rec_size;
-
-		rec_size = ni->_IDM(index_block_size);
-		recs = PAGE_CACHE_SIZE / rec_size;
-		addr = kmap_atomic(page, KM_BIO_SRC_IRQ);
-		for (i = 0; i < recs; i++) {
-			if (!post_read_mst_fixup((NTFS_RECORD*)(addr +
-					i * rec_size), rec_size))
-				continue;
-			nr_err++;
-			ntfs_error(ni->vol->sb, "post_read_mst_fixup() failed, "
-					"corrupt %s record 0x%Lx. Run chkdsk.",
-					ni->mft_no ? "index" : "mft",
-					(long long)((page->index <<
-					PAGE_CACHE_SHIFT >>
-					ni->_IDM(index_block_size_bits)) + i));
-		}
-		flush_dcache_page(page);
-		kunmap_atomic(addr, KM_BIO_SRC_IRQ);
-		if (likely(!nr_err && recs))
-			SetPageUptodate(page);
-		else {
-			ntfs_error(ni->vol->sb, "Setting page error, index "
-					"0x%lx.", page->index);
-			SetPageError(page);
-		}
-	}
-	unlock_page(page);
-	return;
-still_busy:
-	spin_unlock_irqrestore(&page_uptodate_lock, flags);
-	return;
-}
-
-/**
- * ntfs_mst_readpage - fill a @page of the mft or a directory with data
- * @file:	open file/directory to which the page @page belongs or NULL
- * @page:	page cache page to fill with data
- *
- * Readpage method for the VFS address space operations.
- *
- * Fill the page @page of the $MFT or the open directory @dir. We read each
- * buffer asynchronously and when all buffers are read in our io completion
- * handler end_buffer_read_mst_async() automatically applies the mst fixups to
- * the page before finally marking it uptodate and unlocking it.
- *
- * Contains an adapted version of fs/buffer.c::block_read_full_page().
- */
-int ntfs_mst_readpage(struct file *dir, struct page *page)
-{
-	VCN vcn;
-	LCN lcn;
-	ntfs_inode *ni;
-	ntfs_volume *vol;
-	struct buffer_head *bh, *head, *arr[MAX_BUF_PER_PAGE];
-	sector_t iblock, lblock, zblock;
-	unsigned int blocksize, blocks, vcn_ofs;
-	int i, nr;
-	unsigned char blocksize_bits;
-
-	if (!PageLocked(page))
-		PAGE_BUG(page);
-
-	ni = NTFS_I(page->mapping->host);
-	vol = ni->vol;
-
-	blocksize_bits = VFS_I(ni)->i_blkbits;
-	blocksize = 1 << blocksize_bits;
-
-	if (!page_has_buffers(page))
-		create_empty_buffers(page, blocksize, 0);
-	bh = head = page_buffers(page);
-	if (!bh)
-		return -ENOMEM;
-
-	blocks = PAGE_CACHE_SIZE >> blocksize_bits;
-	iblock = page->index << (PAGE_CACHE_SHIFT - blocksize_bits);
-	lblock = (ni->allocated_size + blocksize - 1) >> blocksize_bits;
-	zblock = (ni->initialized_size + blocksize - 1) >> blocksize_bits;
-
-#ifdef DEBUG
-	if (unlikely(!ni->run_list.rl && !ni->mft_no))
-		panic("NTFS: $MFT/$DATA run list has been unmapped! This is a "
-				"very serious bug! Cannot continue...");
-#endif
-
-	/* Loop through all the buffers in the page. */
-	nr = i = 0;
-	do {
-		if (unlikely(buffer_uptodate(bh)))
-			continue;
-		if (unlikely(buffer_mapped(bh))) {
-			arr[nr++] = bh;
-			continue;
-		}
-		bh->b_bdev = vol->sb->s_bdev;
-		/* Is the block within the allowed limits? */
-		if (iblock < lblock) {
-			BOOL is_retry = FALSE;
-
-			/* Convert iblock into corresponding vcn and offset. */
-			vcn = (VCN)iblock << blocksize_bits >>
-					vol->cluster_size_bits;
-			vcn_ofs = ((VCN)iblock << blocksize_bits) &
-					vol->cluster_size_mask;
-retry_remap:
-			/* Convert the vcn to the corresponding lcn. */
-			down_read(&ni->run_list.lock);
-			lcn = vcn_to_lcn(ni->run_list.rl, vcn);
-			up_read(&ni->run_list.lock);
-			/* Successful remap. */
-			if (lcn >= 0) {
-				/* Setup buffer head to correct block. */
-				bh->b_blocknr = ((lcn << vol->cluster_size_bits)
-						+ vcn_ofs) >> blocksize_bits;
-				set_buffer_mapped(bh);
-				/* Only read initialized data blocks. */
-				if (iblock < zblock) {
-					arr[nr++] = bh;
-					continue;
-				}
-				/* Fully non-initialized data block, zero it. */
-				goto handle_zblock;
-			}
-			/* It is a hole, need to zero it. */
-			if (lcn == LCN_HOLE)
-				goto handle_hole;
-			/* If first try and run list unmapped, map and retry. */
-			if (!is_retry && lcn == LCN_RL_NOT_MAPPED) {
-				is_retry = TRUE;
-				if (!map_run_list(ni, vcn))
-					goto retry_remap;
-			}
-			/* Hard error, zero out region. */
-			SetPageError(page);
-			ntfs_error(vol->sb, "vcn_to_lcn(vcn = 0x%Lx) failed "
-					"with error code 0x%Lx%s.",
-					(long long)vcn, (long long)-lcn,
-					is_retry ? " even after retrying" : "");
-			// FIXME: Depending on vol->on_errors, do something.
-		}
-		/*
-		 * Either iblock was outside lblock limits or vcn_to_lcn()
-		 * returned error. Just zero that portion of the page and set
-		 * the buffer uptodate.
-		 */
-handle_hole:
-		bh->b_blocknr = -1UL;
-		clear_buffer_mapped(bh);
-handle_zblock:
-		memset(kmap(page) + i * blocksize, 0, blocksize);
-		flush_dcache_page(page);
-		kunmap(page);
-		set_buffer_uptodate(bh);
-	} while (i++, iblock++, (bh = bh->b_this_page) != head);
-
-	/* Check we have at least one buffer ready for i/o. */
-	if (nr) {
-		/* Lock the buffers. */
-		for (i = 0; i < nr; i++) {
-			struct buffer_head *tbh = arr[i];
-			lock_buffer(tbh);
-			tbh->b_end_io = end_buffer_read_mst_async;
-			set_buffer_async_read(tbh);
-		}
-		/* Finally, start i/o on the buffers. */
-		for (i = 0; i < nr; i++)
-			submit_bh(READ, arr[i]);
-		return 0;
-	}
-	/* No i/o was scheduled on any of the buffers. */
-	if (!PageError(page))
+	if (likely(!PageError(page)))
 		SetPageUptodate(page);
 	else /* Signal synchronous i/o error. */
 		nr = -EIO;

fs/ntfs/mft.c

@@ -102,7 +102,7 @@ extern int ntfs_mst_readpage(struct file *, struct page *);
  * ntfs_mft_aops - address space operations for access to $MFT
  *
  * Address space operations for access to $MFT. This allows us to simply use
- * read_cache_page() in map_mft_record().
+ * ntfs_map_page() in map_mft_record_page().
  */
 struct address_space_operations ntfs_mft_aops = {
 	writepage:	NULL,			/* Write dirty page to disk. */