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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: Christoph Hellwig <hch@lst.de>
Reviewed-by: Dave Chinner <dchinner@redhat.com>
Signed-off-by: Dave Chinner <david@fromorbit.com>
This commit is contained in:
Christoph Hellwig 2016-06-21 09:38:45 +10:00 committed by Dave Chinner
parent 9a286f0e52
commit 8be9f564d2
2 changed files with 93 additions and 0 deletions
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90
fs/iomap.c
View File

@ -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);

3
include/linux/iomap.h
View File

@ -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 */