[PATCH 09/15] fs: iomap based fiemap implementation

Christoph Hellwig
2016-05-09T08:48:04Z

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>
---
fs/iomap.c | 90 +++++++++++++++++++++++++++++++++++++++++++++++++++
include/linux/iomap.h | 3 ++
2 files changed, 93 insertions(+)

diff --git a/fs/iomap.c b/fs/iomap.c
index f84c6eb..7e639bf 100644
--- a/fs/iomap.c
+++ b/fs/iomap.c
@@ -405,3 +405,93 @@ out_unlock:
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);
diff --git a/include/linux/iomap.h b/include/linux/iomap.h
index 854766f..b3deee1 100644
--- a/include/linux/iomap.h
+++ b/include/linux/iomap.h
@@ -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 */