Donate to e Foundation | Murena handsets with /e/OS | Own a part of Murena! Learn more

Commit 267378d4 authored by Chao Yu's avatar Chao Yu Committed by Jaegeuk Kim
Browse files

f2fs: introduce f2fs_seek_block to support SEEK_{DATA, HOLE} in llseek 



In This patch we introduce f2fs_seek_block to support SEEK_{DATA,HOLE} of
lseek(2).

change log from v1:
 o fix bug when lseek from middle of page and fix wrong calculation of
PGOFS_OF_NEXT_DNODE macro.

Signed-off-by: default avatarChao Yu <chao2.yu@samsung.com>
Signed-off-by: default avatarJaegeuk Kim <jaegeuk.kim@samsung.com>
parent 2163d198

fs/f2fs/f2fs.h

+6 −0
Original line number Diff line number Diff line
@@ -1079,6 +1079,12 @@ static inline void f2fs_stop_checkpoint(struct f2fs_sb_info *sbi) 
	((is_inode_flag_set(F2FS_I(i), FI_ACL_MODE)) ? \

	 (F2FS_I(i)->i_acl_mode) : ((i)->i_mode))



/* get offset of first page in next direct node */

#define PGOFS_OF_NEXT_DNODE(pgofs, fi)				\

	((pgofs < ADDRS_PER_INODE(fi)) ? ADDRS_PER_INODE(fi) :	\

	(pgofs - ADDRS_PER_INODE(fi) + ADDRS_PER_BLOCK) /	\

	ADDRS_PER_BLOCK * ADDRS_PER_BLOCK + ADDRS_PER_INODE(fi))



/*

 * file.c

 */

fs/f2fs/file.c

+91 −1
Original line number Diff line number Diff line
@@ -194,6 +194,96 @@ out: 
	return ret;

}



static loff_t f2fs_seek_block(struct file *file, loff_t offset, int whence)

{

	struct inode *inode = file->f_mapping->host;

	loff_t maxbytes = inode->i_sb->s_maxbytes;

	struct dnode_of_data dn;

	pgoff_t pgofs, end_offset;

	loff_t data_ofs = offset, isize;

	int err = 0;



	mutex_lock(&inode->i_mutex);



	isize = i_size_read(inode);

	if (offset >= isize)

		goto fail;



	/* handle inline data case */

	if (f2fs_has_inline_data(inode)) {

		if (whence == SEEK_HOLE)

			data_ofs = isize;

		goto found;

	}



	pgofs = (pgoff_t)(offset >> PAGE_CACHE_SHIFT);



	for (; data_ofs < isize; data_ofs = pgofs << PAGE_CACHE_SHIFT) {

		set_new_dnode(&dn, inode, NULL, NULL, 0);

		err = get_dnode_of_data(&dn, pgofs, LOOKUP_NODE_RA);

		if (err && err != -ENOENT) {

			goto fail;

		} else if (err == -ENOENT) {

			/* direct node is not exist */

			if (whence == SEEK_DATA) {

				pgofs = PGOFS_OF_NEXT_DNODE(pgofs,

							F2FS_I(inode));

				continue;

			} else {

				goto found;

			}

		}



		end_offset = IS_INODE(dn.node_page) ?

			ADDRS_PER_INODE(F2FS_I(inode)) : ADDRS_PER_BLOCK;



		/* find data/hole in dnode block */

		for (; dn.ofs_in_node < end_offset;

				dn.ofs_in_node++, pgofs++,

				data_ofs = pgofs << PAGE_CACHE_SHIFT) {

			block_t blkaddr;

			blkaddr = datablock_addr(dn.node_page, dn.ofs_in_node);



			if ((whence == SEEK_DATA && blkaddr != NULL_ADDR) ||

				(whence == SEEK_HOLE && blkaddr == NULL_ADDR)) {

				f2fs_put_dnode(&dn);

				goto found;

			}

		}

		f2fs_put_dnode(&dn);

	}



	if (whence == SEEK_DATA)

		goto fail;

	else

		data_ofs = isize;

found:

	mutex_unlock(&inode->i_mutex);

	return vfs_setpos(file, data_ofs, maxbytes);

fail:

	mutex_unlock(&inode->i_mutex);

	return -ENXIO;

}



static loff_t f2fs_llseek(struct file *file, loff_t offset, int whence)

{

	struct inode *inode = file->f_mapping->host;

	loff_t maxbytes = inode->i_sb->s_maxbytes;



	switch (whence) {

	case SEEK_SET:

	case SEEK_CUR:

	case SEEK_END:

		return generic_file_llseek_size(file, offset, whence,

						maxbytes, i_size_read(inode));

	case SEEK_DATA:

	case SEEK_HOLE:

		return f2fs_seek_block(file, offset, whence);

	}



	return -EINVAL;

}



static int f2fs_file_mmap(struct file *file, struct vm_area_struct *vma)

{

	file_accessed(file);
@@ -675,7 +765,7 @@ long f2fs_compat_ioctl(struct file *file, unsigned int cmd, unsigned long arg) 
#endif



const struct file_operations f2fs_file_operations = {

	.llseek		= generic_file_llseek,

	.llseek		= f2fs_llseek,

	.read		= do_sync_read,

	.write		= do_sync_write,

	.aio_read	= generic_file_aio_read,