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authorIlya Dryomov <idryomov@gmail.com>2018-02-17 10:41:20 +0100
committerIlya Dryomov <idryomov@gmail.com>2018-04-02 10:12:43 +0200
commit08c1ac508b6dc20ac866e7cdb7279245437c7d26 (patch)
tree5b1eee491292e772b446ceba9729fb6ba4d899f1 /net/ceph/striper.c
parented0811d2d243c4195580a9671266031907c02ca7 (diff)
downloadlinux-08c1ac508b6dc20ac866e7cdb7279245437c7d26.tar.bz2
libceph, ceph: move ceph_calc_file_object_mapping() to striper.c
ceph_calc_file_object_mapping() has nothing to do with osdmaps. Signed-off-by: Ilya Dryomov <idryomov@gmail.com>
Diffstat (limited to 'net/ceph/striper.c')
-rw-r--r--net/ceph/striper.c37
1 files changed, 36 insertions, 1 deletions
diff --git a/net/ceph/striper.c b/net/ceph/striper.c
index bc1e4de30df9..c36462dc86b7 100644
--- a/net/ceph/striper.c
+++ b/net/ceph/striper.c
@@ -5,11 +5,46 @@
#include <linux/math64.h>
#include <linux/slab.h>
-#include <linux/ceph/osdmap.h>
#include <linux/ceph/striper.h>
#include <linux/ceph/types.h>
/*
+ * Map a file extent to a stripe unit within an object.
+ * Fill in objno, offset into object, and object extent length (i.e. the
+ * number of bytes mapped, less than or equal to @l->stripe_unit).
+ *
+ * Example for stripe_count = 3, stripes_per_object = 4:
+ *
+ * blockno | 0 3 6 9 | 1 4 7 10 | 2 5 8 11 | 12 15 18 21 | 13 16 19
+ * stripeno | 0 1 2 3 | 0 1 2 3 | 0 1 2 3 | 4 5 6 7 | 4 5 6
+ * stripepos | 0 | 1 | 2 | 0 | 1
+ * objno | 0 | 1 | 2 | 3 | 4
+ * objsetno | 0 | 1
+ */
+void ceph_calc_file_object_mapping(struct ceph_file_layout *l,
+ u64 off, u64 len,
+ u64 *objno, u64 *objoff, u32 *xlen)
+{
+ u32 stripes_per_object = l->object_size / l->stripe_unit;
+ u64 blockno; /* which su in the file (i.e. globally) */
+ u32 blockoff; /* offset into su */
+ u64 stripeno; /* which stripe */
+ u32 stripepos; /* which su in the stripe,
+ which object in the object set */
+ u64 objsetno; /* which object set */
+ u32 objsetpos; /* which stripe in the object set */
+
+ blockno = div_u64_rem(off, l->stripe_unit, &blockoff);
+ stripeno = div_u64_rem(blockno, l->stripe_count, &stripepos);
+ objsetno = div_u64_rem(stripeno, stripes_per_object, &objsetpos);
+
+ *objno = objsetno * l->stripe_count + stripepos;
+ *objoff = objsetpos * l->stripe_unit + blockoff;
+ *xlen = min_t(u64, len, l->stripe_unit - blockoff);
+}
+EXPORT_SYMBOL(ceph_calc_file_object_mapping);
+
+/*
* Return the last extent with given objno (@object_extents is sorted
* by objno). If not found, return NULL and set @add_pos so that the
* new extent can be added with list_add(add_pos, new_ex).