diff options
Diffstat (limited to 'net/ceph/striper.c')
| -rw-r--r-- | net/ceph/striper.c | 37 |
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). |