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Commit 8be9f564 authored by Christoph Hellwig's avatar Christoph Hellwig Committed by Dave Chinner
Browse files

fs: iomap based fiemap implementation 



Add a simple fiemap implementation based on iomap_ops, partially based
on a previous implementation from Bob Peterson <rpeterso@redhat.com>.

Signed-off-by: default avatarChristoph Hellwig <hch@lst.de>
Reviewed-by: default avatarDave Chinner <dchinner@redhat.com>
Signed-off-by: default avatarDave Chinner <david@fromorbit.com>
parent 9a286f0e

fs/iomap.c

+90 −0
Original line number Diff line number Diff line
@@ -405,3 +405,93 @@ int iomap_page_mkwrite(struct vm_area_struct *vma, struct vm_fault *vmf, 
	return ret;

}

EXPORT_SYMBOL_GPL(iomap_page_mkwrite);



struct fiemap_ctx {

	struct fiemap_extent_info *fi;

	struct iomap prev;

};



static int iomap_to_fiemap(struct fiemap_extent_info *fi,

		struct iomap *iomap, u32 flags)

{

	switch (iomap->type) {

	case IOMAP_HOLE:

		/* skip holes */

		return 0;

	case IOMAP_DELALLOC:

		flags |= FIEMAP_EXTENT_DELALLOC | FIEMAP_EXTENT_UNKNOWN;

		break;

	case IOMAP_UNWRITTEN:

		flags |= FIEMAP_EXTENT_UNWRITTEN;

		break;

	case IOMAP_MAPPED:

		break;

	}



	return fiemap_fill_next_extent(fi, iomap->offset,

			iomap->blkno != IOMAP_NULL_BLOCK ? iomap->blkno << 9: 0,

			iomap->length, flags | FIEMAP_EXTENT_MERGED);



}



static loff_t

iomap_fiemap_actor(struct inode *inode, loff_t pos, loff_t length, void *data,

		struct iomap *iomap)

{

	struct fiemap_ctx *ctx = data;

	loff_t ret = length;



	if (iomap->type == IOMAP_HOLE)

		return length;



	ret = iomap_to_fiemap(ctx->fi, &ctx->prev, 0);

	ctx->prev = *iomap;

	switch (ret) {

	case 0:		/* success */

		return length;

	case 1:		/* extent array full */

		return 0;

	default:

		return ret;

	}

}



int iomap_fiemap(struct inode *inode, struct fiemap_extent_info *fi,

		loff_t start, loff_t len, struct iomap_ops *ops)

{

	struct fiemap_ctx ctx;

	loff_t ret;



	memset(&ctx, 0, sizeof(ctx));

	ctx.fi = fi;

	ctx.prev.type = IOMAP_HOLE;



	ret = fiemap_check_flags(fi, FIEMAP_FLAG_SYNC);

	if (ret)

		return ret;



	ret = filemap_write_and_wait(inode->i_mapping);

	if (ret)

		return ret;



	while (len > 0) {

		ret = iomap_apply(inode, start, len, 0, ops, &ctx,

				iomap_fiemap_actor);

		if (ret < 0)

			return ret;

		if (ret == 0)

			break;



		start += ret;

		len -= ret;

	}



	if (ctx.prev.type != IOMAP_HOLE) {

		ret = iomap_to_fiemap(fi, &ctx.prev, FIEMAP_EXTENT_LAST);

		if (ret < 0)

			return ret;

	}



	return 0;

}

EXPORT_SYMBOL_GPL(iomap_fiemap);

include/linux/iomap.h

+3 −0
Original line number Diff line number Diff line
@@ -3,6 +3,7 @@ 


#include <linux/types.h>



struct fiemap_extent_info;

struct inode;

struct iov_iter;

struct kiocb;
@@ -63,5 +64,7 @@ int iomap_truncate_page(struct inode *inode, loff_t pos, bool *did_zero, 
		struct iomap_ops *ops);

int iomap_page_mkwrite(struct vm_area_struct *vma, struct vm_fault *vmf,

		struct iomap_ops *ops);

int iomap_fiemap(struct inode *inode, struct fiemap_extent_info *fieinfo,

		loff_t start, loff_t len, struct iomap_ops *ops);



#endif /* LINUX_IOMAP_H */