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Commit 996bb9fd authored by Theodore Ts'o's avatar Theodore Ts'o
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ext4: support simple conversion of extent-mapped inodes to use i_blocks 



In order to make it simpler to test the code which support
i_blocks/indirect-mapped inodes, support the conversion of inodes
which are less than 12 blocks and which are contained in no more than
a single extent.

The primary intended use of this code is to converting freshly created
zero-length files and empty directories.

Note that the version of chattr in e2fsprogs 1.42.7 and earlier has a
check that prevents the clearing of the extent flag.  A simple patch
which allows "chattr -e <file>" to work will be checked into the
e2fsprogs git repository.

Signed-off-by: default avatar"Theodore Ts'o" <tytso@mit.edu>
parent d76a3a77

fs/ext4/ext4.h

+2 −1
Original line number Diff line number Diff line
@@ -403,7 +403,7 @@ struct flex_groups { 
#define EXT4_RESERVED_FL		0x80000000 /* reserved for ext4 lib */



#define EXT4_FL_USER_VISIBLE		0x004BDFFF /* User visible flags */

#define EXT4_FL_USER_MODIFIABLE		0x004B80FF /* User modifiable flags */

#define EXT4_FL_USER_MODIFIABLE		0x004380FF /* User modifiable flags */



/* Flags that should be inherited by new inodes from their parent. */

#define EXT4_FL_INHERITED (EXT4_SECRM_FL | EXT4_UNRM_FL | EXT4_COMPR_FL |\
@@ -2608,6 +2608,7 @@ extern int ext4_find_delalloc_range(struct inode *inode, 
extern int ext4_find_delalloc_cluster(struct inode *inode, ext4_lblk_t lblk);

extern int ext4_fiemap(struct inode *inode, struct fiemap_extent_info *fieinfo,

			__u64 start, __u64 len);

extern int ext4_ind_migrate(struct inode *inode);





/* move_extent.c */

fs/ext4/extents.c

+59 −0
Original line number Diff line number Diff line
@@ -4610,3 +4610,62 @@ int ext4_fiemap(struct inode *inode, struct fiemap_extent_info *fieinfo, 


	return error;

}



/*

 * Migrate a simple extent-based inode to use the i_blocks[] array

 */

int ext4_ind_migrate(struct inode *inode)

{

	struct ext4_extent_header	*eh;

	struct ext4_super_block		*es = EXT4_SB(inode->i_sb)->s_es;

	struct ext4_inode_info		*ei = EXT4_I(inode);

	struct ext4_extent		*ex;

	unsigned int			i, len;

	ext4_fsblk_t			blk;

	handle_t			*handle;

	int				ret;



	if (!EXT4_HAS_INCOMPAT_FEATURE(inode->i_sb,

				       EXT4_FEATURE_INCOMPAT_EXTENTS) ||

	    (!ext4_test_inode_flag(inode, EXT4_INODE_EXTENTS)))

		return -EINVAL;



	down_write(&EXT4_I(inode)->i_data_sem);

	ret = ext4_ext_check_inode(inode);

	if (ret)

		goto errout;



	eh = ext_inode_hdr(inode);

	ex  = EXT_FIRST_EXTENT(eh);

	if (ext4_blocks_count(es) > EXT4_MAX_BLOCK_FILE_PHYS ||

	    eh->eh_depth != 0 || eh->eh_entries > 1) {

		ret = -EOPNOTSUPP;

		goto errout;

	}

	if (eh->eh_entries == 0)

		blk = len = 0;

	else {

		len = le16_to_cpu(ex->ee_len);

		blk = ext4_ext_pblock(ex);

		if (len > EXT4_NDIR_BLOCKS) {

			ret = -EOPNOTSUPP;

			goto errout;

		}

	}



	handle = ext4_journal_start(inode, EXT4_HT_MIGRATE, 1);

	if (IS_ERR(handle)) {

		ret = PTR_ERR(handle);

		goto errout;

	}



	ext4_clear_inode_flag(inode, EXT4_INODE_EXTENTS);

	memset(ei->i_data, 0, sizeof(ei->i_data));

	for (i=0; i < len; i++)

		ei->i_data[i] = cpu_to_le32(blk++);

	ext4_mark_inode_dirty(handle, inode);

	ext4_journal_stop(handle);

errout:

	up_write(&EXT4_I(inode)->i_data_sem);

	return ret;

}

fs/ext4/ioctl.c

+8 −12
Original line number Diff line number Diff line
@@ -83,17 +83,8 @@ long ext4_ioctl(struct file *filp, unsigned int cmd, unsigned long arg) 
			if (!capable(CAP_SYS_RESOURCE))

				goto flags_out;

		}

		if (oldflags & EXT4_EXTENTS_FL) {

			/* We don't support clearning extent flags */

			if (!(flags & EXT4_EXTENTS_FL)) {

				err = -EOPNOTSUPP;

				goto flags_out;

			}

		} else if (flags & EXT4_EXTENTS_FL) {

			/* migrate the file */

		if ((flags ^ oldflags) & EXT4_EXTENTS_FL)

			migrate = 1;

			flags &= ~EXT4_EXTENTS_FL;

		}



		if (flags & EXT4_EOFBLOCKS_FL) {

			/* we don't support adding EOFBLOCKS flag */
@@ -137,8 +128,13 @@ long ext4_ioctl(struct file *filp, unsigned int cmd, unsigned long arg) 
			err = ext4_change_inode_journal_flag(inode, jflag);

		if (err)

			goto flags_out;

		if (migrate)

		if (migrate) {

			if (flags & EXT4_EXTENTS_FL)

				err = ext4_ext_migrate(inode);

			else

				err = ext4_ind_migrate(inode);

		}



flags_out:

		mutex_unlock(&inode->i_mutex);

		mnt_drop_write_file(filp);