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Commit 556615dc authored by Lukas Czerner's avatar Lukas Czerner Committed by Theodore Ts'o
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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: default avatarLukas Czerner <lczerner@redhat.com>
Signed-off-by: default avatar"Theodore Ts'o" <tytso@mit.edu>
parent 090f32ee

fs/ext4/ext4.h

+8 −8
Original line number Diff line number Diff line
@@ -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

+11 −11
Original line number Diff line number Diff line
@@ -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.c

+109 −109

File changed.

Preview size limit exceeded, changes collapsed.

fs/ext4/extents_status.c

+1 −1
Original line number Diff line number Diff line
@@ -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

+1 −1
Original line number Diff line number Diff line
@@ -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.