ext4: rename uninitialized extents to unwritten

Currently in ext4 there is quite a mess when it comes to naming
unwritten extents. Sometimes we call it uninitialized and sometimes we
refer to it as unwritten.

The right name for the extent which has been allocated but does not
contain any written data is _unwritten_. Other file systems are
using this name consistently, even the buffer head state refers to it as
unwritten. We need to fix this confusion in ext4.

This commit changes every reference to an uninitialized extent (meaning
allocated but unwritten) to unwritten extent. This includes comments,
function names and variable names. It even covers abbreviation of the
word uninitialized (such as uninit) and some misspellings.

This commit does not change any of the code paths at all. This has been
confirmed by comparing md5sums of the assembly code of each object file
after all the function names were stripped from it.
Signed-off-by: Lukas Czerner <lczerner@redhat.com>
Signed-off-by: "Theodore Ts'o" <tytso@mit.edu>

fs/ext4/ext4.h

@@ -183,7 +183,7 @@ struct ext4_map_blocks {
 #define	EXT4_IO_END_UNWRITTEN	0x0001
 
 /*
- * For converting uninitialized extents on a work queue. 'handle' is used for
+ * For converting unwritten extents on a work queue. 'handle' is used for
  * buffered writeback.
  */
 typedef struct ext4_io_end {
@@ -536,26 +536,26 @@ enum {
 /*
  * Flags used by ext4_map_blocks()
  */
-	/* Allocate any needed blocks and/or convert an unitialized
+	/* Allocate any needed blocks and/or convert an unwritten
 	   extent to be an initialized ext4 */
 #define EXT4_GET_BLOCKS_CREATE			0x0001
-	/* Request the creation of an unitialized extent */
-#define EXT4_GET_BLOCKS_UNINIT_EXT		0x0002
-#define EXT4_GET_BLOCKS_CREATE_UNINIT_EXT	(EXT4_GET_BLOCKS_UNINIT_EXT|\
+	/* Request the creation of an unwritten extent */
+#define EXT4_GET_BLOCKS_UNWRIT_EXT		0x0002
+#define EXT4_GET_BLOCKS_CREATE_UNWRIT_EXT	(EXT4_GET_BLOCKS_UNWRIT_EXT|\
 						 EXT4_GET_BLOCKS_CREATE)
 	/* Caller is from the delayed allocation writeout path
 	 * finally doing the actual allocation of delayed blocks */
 #define EXT4_GET_BLOCKS_DELALLOC_RESERVE	0x0004
 	/* caller is from the direct IO path, request to creation of an
-	unitialized extents if not allocated, split the uninitialized
+	unwritten extents if not allocated, split the unwritten
 	extent if blocks has been preallocated already*/
 #define EXT4_GET_BLOCKS_PRE_IO			0x0008
 #define EXT4_GET_BLOCKS_CONVERT			0x0010
 #define EXT4_GET_BLOCKS_IO_CREATE_EXT		(EXT4_GET_BLOCKS_PRE_IO|\
-					 EXT4_GET_BLOCKS_CREATE_UNINIT_EXT)
+					 EXT4_GET_BLOCKS_CREATE_UNWRIT_EXT)
 	/* Convert extent to initialized after IO complete */
 #define EXT4_GET_BLOCKS_IO_CONVERT_EXT		(EXT4_GET_BLOCKS_CONVERT|\
-					 EXT4_GET_BLOCKS_CREATE_UNINIT_EXT)
+					 EXT4_GET_BLOCKS_CREATE_UNWRIT_EXT)
 	/* Eventual metadata allocation (due to growing extent tree)
 	 * should not fail, so try to use reserved blocks for that.*/
 #define EXT4_GET_BLOCKS_METADATA_NOFAIL		0x0020

fs/ext4/ext4_extents.h

@@ -137,21 +137,21 @@ struct ext4_ext_path {
  * EXT_INIT_MAX_LEN is the maximum number of blocks we can have in an
  * initialized extent. This is 2^15 and not (2^16 - 1), since we use the
  * MSB of ee_len field in the extent datastructure to signify if this
- * particular extent is an initialized extent or an uninitialized (i.e.
+ * particular extent is an initialized extent or an unwritten (i.e.
  * preallocated).
- * EXT_UNINIT_MAX_LEN is the maximum number of blocks we can have in an
- * uninitialized extent.
+ * EXT_UNWRITTEN_MAX_LEN is the maximum number of blocks we can have in an
+ * unwritten extent.
  * If ee_len is <= 0x8000, it is an initialized extent. Otherwise, it is an
- * uninitialized one. In other words, if MSB of ee_len is set, it is an
- * uninitialized extent with only one special scenario when ee_len = 0x8000.
- * In this case we can not have an uninitialized extent of zero length and
+ * unwritten one. In other words, if MSB of ee_len is set, it is an
+ * unwritten extent with only one special scenario when ee_len = 0x8000.
+ * In this case we can not have an unwritten extent of zero length and
  * thus we make it as a special case of initialized extent with 0x8000 length.
  * This way we get better extent-to-group alignment for initialized extents.
  * Hence, the maximum number of blocks we can have in an *initialized*
- * extent is 2^15 (32768) and in an *uninitialized* extent is 2^15-1 (32767).
+ * extent is 2^15 (32768) and in an *unwritten* extent is 2^15-1 (32767).
  */
 #define EXT_INIT_MAX_LEN	(1UL << 15)
-#define EXT_UNINIT_MAX_LEN	(EXT_INIT_MAX_LEN - 1)
+#define EXT_UNWRITTEN_MAX_LEN	(EXT_INIT_MAX_LEN - 1)
 
 
 #define EXT_FIRST_EXTENT(__hdr__) \
@@ -187,14 +187,14 @@ static inline unsigned short ext_depth(struct inode *inode)
 	return le16_to_cpu(ext_inode_hdr(inode)->eh_depth);
 }
 
-static inline void ext4_ext_mark_uninitialized(struct ext4_extent *ext)
+static inline void ext4_ext_mark_unwritten(struct ext4_extent *ext)
 {
-	/* We can not have an uninitialized extent of zero length! */
+	/* We can not have an unwritten extent of zero length! */
 	BUG_ON((le16_to_cpu(ext->ee_len) & ~EXT_INIT_MAX_LEN) == 0);
 	ext->ee_len |= cpu_to_le16(EXT_INIT_MAX_LEN);
 }
 
-static inline int ext4_ext_is_uninitialized(struct ext4_extent *ext)
+static inline int ext4_ext_is_unwritten(struct ext4_extent *ext)
 {
 	/* Extent with ee_len of 0x8000 is treated as an initialized extent */
 	return (le16_to_cpu(ext->ee_len) > EXT_INIT_MAX_LEN);

fs/ext4/extents_status.c

@@ -433,7 +433,7 @@ static void ext4_es_insert_extent_ext_check(struct inode *inode,
 		ee_start = ext4_ext_pblock(ex);
 		ee_len = ext4_ext_get_actual_len(ex);
 
-		ee_status = ext4_ext_is_uninitialized(ex) ? 1 : 0;
+		ee_status = ext4_ext_is_unwritten(ex) ? 1 : 0;
 		es_status = ext4_es_is_unwritten(es) ? 1 : 0;
 
 		/*

fs/ext4/file.c

@@ -136,7 +136,7 @@ ext4_file_dio_write(struct kiocb *iocb, const struct iovec *iov,
 		/*
 		 * 'err==len' means that all of blocks has been preallocated no
 		 * matter they are initialized or not.  For excluding
-		 * uninitialized extents, we need to check m_flags.  There are
+		 * unwritten extents, we need to check m_flags.  There are
 		 * two conditions that indicate for initialized extents.
 		 * 1) If we hit extent cache, EXT4_MAP_MAPPED flag is returned;
 		 * 2) If we do a real lookup, non-flags are returned.

fs/ext4/inode.c

@@ -489,8 +489,8 @@ static void ext4_map_blocks_es_recheck(handle_t *handle,
  * Otherwise, call with ext4_ind_map_blocks() to handle indirect mapping
  * based files
  *
- * On success, it returns the number of blocks being mapped or allocate.
- * if create==0 and the blocks are pre-allocated and uninitialized block,
+ * On success, it returns the number of blocks being mapped or allocated.
+ * if create==0 and the blocks are pre-allocated and unwritten block,
  * the result buffer head is unmapped. If the create ==1, it will make sure
  * the buffer head is mapped.
  *
@@ -622,7 +622,7 @@ int ext4_map_blocks(handle_t *handle, struct inode *inode,
 	map->m_flags &= ~EXT4_MAP_FLAGS;
 
 	/*
-	 * New blocks allocate and/or writing to uninitialized extent
+	 * New blocks allocate and/or writing to unwritten extent
 	 * will possibly result in updating i_data, so we take
 	 * the write lock of i_data_sem, and call get_blocks()
 	 * with create == 1 flag.
@@ -2032,7 +2032,7 @@ static int mpage_process_page_bufs(struct mpage_da_data *mpd,
  * Scan buffers corresponding to changed extent (we expect corresponding pages
  * to be already locked) and update buffer state according to new extent state.
  * We map delalloc buffers to their physical location, clear unwritten bits,
- * and mark buffers as uninit when we perform writes to uninitialized extents
+ * and mark buffers as uninit when we perform writes to unwritten extents
  * and do extent conversion after IO is finished. If the last page is not fully
  * mapped, we update @map to the next extent in the last page that needs
  * mapping. Otherwise we submit the page for IO.
@@ -2131,7 +2131,7 @@ static int mpage_map_one_extent(handle_t *handle, struct mpage_da_data *mpd)
 	trace_ext4_da_write_pages_extent(inode, map);
 	/*
 	 * Call ext4_map_blocks() to allocate any delayed allocation blocks, or
-	 * to convert an uninitialized extent to be initialized (in the case
+	 * to convert an unwritten extent to be initialized (in the case
 	 * where we have written into one or more preallocated blocks).  It is
 	 * possible that we're going to need more metadata blocks than
 	 * previously reserved. However we must not fail because we're in
@@ -3071,9 +3071,9 @@ static void ext4_end_io_dio(struct kiocb *iocb, loff_t offset,
  * preallocated extents, and those write extend the file, no need to
  * fall back to buffered IO.
  *
- * For holes, we fallocate those blocks, mark them as uninitialized
+ * For holes, we fallocate those blocks, mark them as unwritten
  * If those blocks were preallocated, we mark sure they are split, but
- * still keep the range to write as uninitialized.
+ * still keep the range to write as unwritten.
  *
  * The unwritten extents will be converted to written when DIO is completed.
  * For async direct IO, since the IO may still pending when return, we
@@ -3125,12 +3125,12 @@ static ssize_t ext4_ext_direct_IO(int rw, struct kiocb *iocb,
 	 * We could direct write to holes and fallocate.
 	 *
 	 * Allocated blocks to fill the hole are marked as
-	 * uninitialized to prevent parallel buffered read to expose
+	 * unwritten to prevent parallel buffered read to expose
 	 * the stale data before DIO complete the data IO.
 	 *
 	 * As to previously fallocated extents, ext4 get_block will
 	 * just simply mark the buffer mapped but still keep the
-	 * extents uninitialized.
+	 * extents unwritten.
 	 *
 	 * For non AIO case, we will convert those unwritten extents
 	 * to written after return back from blockdev_direct_IO.

fs/ext4/move_extent.c

@@ -57,8 +57,8 @@ get_ext_path(struct inode *inode, ext4_lblk_t lblock,
 static void
 copy_extent_status(struct ext4_extent *src, struct ext4_extent *dest)
 {
-	if (ext4_ext_is_uninitialized(src))
-		ext4_ext_mark_uninitialized(dest);
+	if (ext4_ext_is_unwritten(src))
+		ext4_ext_mark_unwritten(dest);
 	else
 		dest->ee_len = cpu_to_le16(ext4_ext_get_actual_len(dest));
 }
@@ -593,14 +593,14 @@ mext_calc_swap_extents(struct ext4_extent *tmp_dext,
  * @inode:		inode in question
  * @from:		block offset of inode
  * @count:		block count to be checked
- * @uninit:		extents expected to be uninitialized
+ * @unwritten:		extents expected to be unwritten
  * @err:		pointer to save error value
  *
  * Return 1 if all extents in range has expected type, and zero otherwise.
  */
 static int
 mext_check_coverage(struct inode *inode, ext4_lblk_t from, ext4_lblk_t count,
-			  int uninit, int *err)
+		    int unwritten, int *err)
 {
 	struct ext4_ext_path *path = NULL;
 	struct ext4_extent *ext;
@@ -611,7 +611,7 @@ mext_check_coverage(struct inode *inode, ext4_lblk_t from, ext4_lblk_t count,
 		if (*err)
 			goto out;
 		ext = path[ext_depth(inode)].p_ext;
-		if (uninit != ext4_ext_is_uninitialized(ext))
+		if (unwritten != ext4_ext_is_unwritten(ext))
 			goto out;
 		from += ext4_ext_get_actual_len(ext);
 		ext4_ext_drop_refs(path);
@@ -894,7 +894,7 @@ mext_page_mkuptodate(struct page *page, unsigned from, unsigned to)
  * @orig_page_offset:		page index on original file
  * @data_offset_in_page:	block index where data swapping starts
  * @block_len_in_page:		the number of blocks to be swapped
- * @uninit:			orig extent is uninitialized or not
+ * @unwritten:			orig extent is unwritten or not
  * @err:			pointer to save return value
  *
  * Save the data in original inode blocks and replace original inode extents
@@ -905,7 +905,7 @@ mext_page_mkuptodate(struct page *page, unsigned from, unsigned to)
 static int
 move_extent_per_page(struct file *o_filp, struct inode *donor_inode,
 		  pgoff_t orig_page_offset, int data_offset_in_page,
-		  int block_len_in_page, int uninit, int *err)
+		  int block_len_in_page, int unwritten, int *err)
 {
 	struct inode *orig_inode = file_inode(o_filp);
 	struct page *pagep[2] = {NULL, NULL};
@@ -962,27 +962,27 @@ move_extent_per_page(struct file *o_filp, struct inode *donor_inode,
 	if (unlikely(*err < 0))
 		goto stop_journal;
 	/*
-	 * If orig extent was uninitialized it can become initialized
+	 * If orig extent was unwritten it can become initialized
 	 * at any time after i_data_sem was dropped, in order to
 	 * serialize with delalloc we have recheck extent while we
 	 * hold page's lock, if it is still the case data copy is not
 	 * necessary, just swap data blocks between orig and donor.
 	 */
-	if (uninit) {
+	if (unwritten) {
 		ext4_double_down_write_data_sem(orig_inode, donor_inode);
 		/* If any of extents in range became initialized we have to
 		 * fallback to data copying */
-		uninit = mext_check_coverage(orig_inode, orig_blk_offset,
-					     block_len_in_page, 1, err);
+		unwritten = mext_check_coverage(orig_inode, orig_blk_offset,
+						block_len_in_page, 1, err);
 		if (*err)
 			goto drop_data_sem;
 
-		uninit &= mext_check_coverage(donor_inode, orig_blk_offset,
-					      block_len_in_page, 1, err);
+		unwritten &= mext_check_coverage(donor_inode, orig_blk_offset,
+						 block_len_in_page, 1, err);
 		if (*err)
 			goto drop_data_sem;
 
-		if (!uninit) {
+		if (!unwritten) {
 			ext4_double_up_write_data_sem(orig_inode, donor_inode);
 			goto data_copy;
 		}
@@ -1259,7 +1259,7 @@ ext4_move_extents(struct file *o_filp, struct file *d_filp,
 	int blocks_per_page = PAGE_CACHE_SIZE >> orig_inode->i_blkbits;
 	int data_offset_in_page;
 	int block_len_in_page;
-	int uninit;
+	int unwritten;
 
 	if (orig_inode->i_sb != donor_inode->i_sb) {
 		ext4_debug("ext4 move extent: The argument files "
@@ -1391,8 +1391,8 @@ ext4_move_extents(struct file *o_filp, struct file *d_filp,
 		    !last_extent)
 			continue;
 
-		/* Is original extent is uninitialized */
-		uninit = ext4_ext_is_uninitialized(ext_prev);
+		/* Is original extent is unwritten */
+		unwritten = ext4_ext_is_unwritten(ext_prev);
 
 		data_offset_in_page = seq_start % blocks_per_page;
 
@@ -1432,8 +1432,8 @@ ext4_move_extents(struct file *o_filp, struct file *d_filp,
 						o_filp, donor_inode,
 						orig_page_offset,
 						data_offset_in_page,
-						block_len_in_page, uninit,
-						&ret);
+						block_len_in_page,
+						unwritten, &ret);
 
 			/* Count how many blocks we have exchanged */
 			*moved_len += block_len_in_page;

fs/ext4/super.c

@@ -3337,7 +3337,7 @@ static ext4_fsblk_t ext4_calculate_resv_clusters(struct super_block *sb)
 	 * By default we reserve 2% or 4096 clusters, whichever is smaller.
 	 * This should cover the situations where we can not afford to run
 	 * out of space like for example punch hole, or converting
-	 * uninitialized extents in delalloc path. In most cases such
+	 * unwritten extents in delalloc path. In most cases such
 	 * allocation would require 1, or 2 blocks, higher numbers are
 	 * very rare.
 	 */

include/trace/events/ext4.h

@@ -36,7 +36,7 @@ struct extent_status;
 
 #define show_map_flags(flags) __print_flags(flags, "|",			\
 	{ EXT4_GET_BLOCKS_CREATE,		"CREATE" },		\
-	{ EXT4_GET_BLOCKS_UNINIT_EXT,		"UNINIT" },		\
+	{ EXT4_GET_BLOCKS_UNWRIT_EXT,		"UNWRIT" },		\
 	{ EXT4_GET_BLOCKS_DELALLOC_RESERVE,	"DELALLOC" },		\
 	{ EXT4_GET_BLOCKS_PRE_IO,		"PRE_IO" },		\
 	{ EXT4_GET_BLOCKS_CONVERT,		"CONVERT" },		\
@@ -1496,7 +1496,7 @@ DEFINE_EVENT(ext4__truncate, ext4_truncate_exit,
 	TP_ARGS(inode)
 );
 
-/* 'ux' is the uninitialized extent. */
+/* 'ux' is the unwritten extent. */
 TRACE_EVENT(ext4_ext_convert_to_initialized_enter,
 	TP_PROTO(struct inode *inode, struct ext4_map_blocks *map,
 		 struct ext4_extent *ux),
@@ -1532,7 +1532,7 @@ TRACE_EVENT(ext4_ext_convert_to_initialized_enter,
 );
 
 /*
- * 'ux' is the uninitialized extent.
+ * 'ux' is the unwritten extent.
  * 'ix' is the initialized extent to which blocks are transferred.
  */
 TRACE_EVENT(ext4_ext_convert_to_initialized_fastpath,
@@ -1810,7 +1810,7 @@ DEFINE_EVENT(ext4__trim, ext4_trim_all_free,
 	TP_ARGS(sb, group, start, len)
 );
 
-TRACE_EVENT(ext4_ext_handle_uninitialized_extents,
+TRACE_EVENT(ext4_ext_handle_unwritten_extents,
 	TP_PROTO(struct inode *inode, struct ext4_map_blocks *map, int flags,
 		 unsigned int allocated, ext4_fsblk_t newblock),