This patch moves the iomap infrastructure from its current location in
exportfs.h to a new iomap.h. This may be used not only by nfs, but also by
other file systems. This also adds an iomap function call to the
address_space_operations. This will facilitate future improvements such
as a more efficient fiemap for holey files. Hopefully it will one day be
used for multipage writes as well.
Signed-off-by: Bob Peterson <rpeterso@xxxxxxxxxx>
---
include/linux/exportfs.h | 16 +---------------
include/linux/fs.h | 4 ++++
include/linux/iomap.h | 39 +++++++++++++++++++++++++++++++++++++++
3 files changed, 44 insertions(+), 15 deletions(-)
create mode 100644 include/linux/iomap.h
diff --git a/include/linux/exportfs.h b/include/linux/exportfs.h
index fa05e04..bb564c1 100644
--- a/include/linux/exportfs.h
+++ b/include/linux/exportfs.h
@@ -2,6 +2,7 @@
#define LINUX_EXPORTFS_H 1
#include <linux/types.h>
+#include <linux/iomap.h>
struct dentry;
struct iattr;
@@ -181,21 +182,6 @@ struct fid {
* get_name is not (which is possibly inconsistent)
*/
-/* types of block ranges for multipage write mappings. */
-#define IOMAP_HOLE 0x01 /* no blocks allocated, need allocation */
-#define IOMAP_DELALLOC 0x02 /* delayed allocation blocks */
-#define IOMAP_MAPPED 0x03 /* blocks allocated @blkno */
-#define IOMAP_UNWRITTEN 0x04 /* blocks allocated @blkno in unwritten state */
-
-#define IOMAP_NULL_BLOCK -1LL /* blkno is not valid */
-
-struct iomap {
- sector_t blkno; /* first sector of mapping */
- loff_t offset; /* file offset of mapping, bytes */
- u64 length; /* length of mapping, bytes */
- int type; /* type of mapping */
-};
-
struct export_operations {
int (*encode_fh)(struct inode *inode, __u32 *fh, int *max_len,
struct inode *parent);
diff --git a/include/linux/fs.h b/include/linux/fs.h
index daf399d..8bafb11 100644
--- a/include/linux/fs.h
+++ b/include/linux/fs.h
@@ -21,6 +21,7 @@
#include <linux/capability.h>
#include <linux/semaphore.h>
#include <linux/fiemap.h>
+#include <linux/iomap.h>
#include <linux/rculist_bl.h>
#include <linux/atomic.h>
#include <linux/shrinker.h>
@@ -316,6 +317,7 @@ enum positive_aop_returns {
struct page;
struct address_space;
struct writeback_control;
+struct iomap;
#define IOCB_EVENTFD (1 << 0)
#define IOCB_APPEND (1 << 1)
@@ -403,6 +405,8 @@ struct address_space_operations {
unsigned long);
void (*is_dirty_writeback) (struct page *, bool *, bool *);
int (*error_remove_page)(struct address_space *, struct page *);
+ int (*iomap)(struct address_space *mapping, loff_t pos,
+ ssize_t length, struct iomap *iomap, int cmd);
/* swapfile support */
int (*swap_activate)(struct swap_info_struct *sis, struct file *file,
diff --git a/include/linux/iomap.h b/include/linux/iomap.h
new file mode 100644
index 0000000..8da4c1e
--- /dev/null
+++ b/include/linux/iomap.h
@@ -0,0 +1,39 @@
+#ifndef _IOMAP_H
+#define _IOMAP_H
+
+/* ->iomap a_op command types */
+#define IOMAP_READ 0x01 /* read the current mapping starting at the
+ given position, trimmed to a maximum length.
+ FS's should use this to obtain and lock
+ resources within this range */
+#define IOMAP_RESERVE 0x02 /* reserve space for an allocation that spans
+ the given iomap */
+#define IOMAP_ALLOCATE 0x03 /* allocate space in a given iomap - must have
+ first been reserved */
+#define IOMAP_UNRESERVE 0x04 /* return unused reserved space for the given
+ iomap and used space. This will always be
+ called after a IOMAP_READ so as to allow the
+ FS to release held resources. */
+
+/* types of block ranges for multipage write mappings. */
+#define IOMAP_HOLE 0x01 /* no blocks allocated, need allocation */
+#define IOMAP_DELALLOC 0x02 /* delayed allocation blocks */
+#define IOMAP_MAPPED 0x03 /* blocks allocated @blkno */
+#define IOMAP_UNWRITTEN 0x04 /* blocks allocated @blkno in unwritten state */
+
+#define IOMAP_NULL_BLOCK -1LL /* blkno is not valid */
+
+struct iomap {
+ sector_t blkno; /* first sector of mapping */
+ loff_t offset; /* file offset of mapping, bytes */
+ ssize_t length; /* length of mapping, bytes */
+ int type; /* type of mapping */
+ void *priv; /* fs private data associated with map */
+};
+
+static inline bool iomap_needs_allocation(struct iomap *iomap)
+{
+ return iomap->type == IOMAP_HOLE;
+}
+
+#endif /* _IOMAP_H */
--
2.5.0
--
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