diff options
Diffstat (limited to 'net/ceph/striper.c')
| -rw-r--r-- | net/ceph/striper.c | 226 |
1 files changed, 226 insertions, 0 deletions
diff --git a/net/ceph/striper.c b/net/ceph/striper.c new file mode 100644 index 000000000000..bc1e4de30df9 --- /dev/null +++ b/net/ceph/striper.c @@ -0,0 +1,226 @@ +/* SPDX-License-Identifier: GPL-2.0 */ + +#include <linux/ceph/ceph_debug.h> + +#include <linux/math64.h> +#include <linux/slab.h> + +#include <linux/ceph/osdmap.h> +#include <linux/ceph/striper.h> +#include <linux/ceph/types.h> + +/* + * 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). + */ +static struct ceph_object_extent * +lookup_last(struct list_head *object_extents, u64 objno, + struct list_head **add_pos) +{ + struct list_head *pos; + + list_for_each_prev(pos, object_extents) { + struct ceph_object_extent *ex = + list_entry(pos, typeof(*ex), oe_item); + + if (ex->oe_objno == objno) + return ex; + + if (ex->oe_objno < objno) + break; + } + + *add_pos = pos; + return NULL; +} + +static struct ceph_object_extent * +lookup_containing(struct list_head *object_extents, u64 objno, + u64 objoff, u32 xlen) +{ + struct ceph_object_extent *ex; + + list_for_each_entry(ex, object_extents, oe_item) { + if (ex->oe_objno == objno && + ex->oe_off <= objoff && + ex->oe_off + ex->oe_len >= objoff + xlen) /* paranoia */ + return ex; + + if (ex->oe_objno > objno) + break; + } + + return NULL; +} + +/* + * Map a file extent to a sorted list of object extents. + * + * We want only one (or as few as possible) object extents per object. + * Adjacent object extents will be merged together, each returned object + * extent may reverse map to multiple different file extents. + * + * Call @alloc_fn for each new object extent and @action_fn for each + * mapped stripe unit, whether it was merged into an already allocated + * object extent or started a new object extent. + * + * Newly allocated object extents are added to @object_extents. + * To keep @object_extents sorted, successive calls to this function + * must map successive file extents (i.e. the list of file extents that + * are mapped using the same @object_extents must be sorted). + * + * The caller is responsible for @object_extents. + */ +int ceph_file_to_extents(struct ceph_file_layout *l, u64 off, u64 len, + struct list_head *object_extents, + struct ceph_object_extent *alloc_fn(void *arg), + void *alloc_arg, + ceph_object_extent_fn_t action_fn, + void *action_arg) +{ + struct ceph_object_extent *last_ex, *ex; + + while (len) { + struct list_head *add_pos = NULL; + u64 objno, objoff; + u32 xlen; + + ceph_calc_file_object_mapping(l, off, len, &objno, &objoff, + &xlen); + + last_ex = lookup_last(object_extents, objno, &add_pos); + if (!last_ex || last_ex->oe_off + last_ex->oe_len != objoff) { + ex = alloc_fn(alloc_arg); + if (!ex) + return -ENOMEM; + + ex->oe_objno = objno; + ex->oe_off = objoff; + ex->oe_len = xlen; + if (action_fn) + action_fn(ex, xlen, action_arg); + + if (!last_ex) + list_add(&ex->oe_item, add_pos); + else + list_add(&ex->oe_item, &last_ex->oe_item); + } else { + last_ex->oe_len += xlen; + if (action_fn) + action_fn(last_ex, xlen, action_arg); + } + + off += xlen; + len -= xlen; + } + + for (last_ex = list_first_entry(object_extents, typeof(*ex), oe_item), + ex = list_next_entry(last_ex, oe_item); + &ex->oe_item != object_extents; + last_ex = ex, ex = list_next_entry(ex, oe_item)) { + if (last_ex->oe_objno > ex->oe_objno || + (last_ex->oe_objno == ex->oe_objno && + last_ex->oe_off + last_ex->oe_len >= ex->oe_off)) { + WARN(1, "%s: object_extents list not sorted!\n", + __func__); + return -EINVAL; + } + } + + return 0; +} +EXPORT_SYMBOL(ceph_file_to_extents); + +/* + * A stripped down, non-allocating version of ceph_file_to_extents(), + * for when @object_extents is already populated. + */ +int ceph_iterate_extents(struct ceph_file_layout *l, u64 off, u64 len, + struct list_head *object_extents, + ceph_object_extent_fn_t action_fn, + void *action_arg) +{ + while (len) { + struct ceph_object_extent *ex; + u64 objno, objoff; + u32 xlen; + + ceph_calc_file_object_mapping(l, off, len, &objno, &objoff, + &xlen); + + ex = lookup_containing(object_extents, objno, objoff, xlen); + if (!ex) { + WARN(1, "%s: objno %llu %llu~%u not found!\n", + __func__, objno, objoff, xlen); + return -EINVAL; + } + + action_fn(ex, xlen, action_arg); + + off += xlen; + len -= xlen; + } + + return 0; +} +EXPORT_SYMBOL(ceph_iterate_extents); + +/* + * Reverse map an object extent to a sorted list of file extents. + * + * On success, the caller is responsible for: + * + * kfree(file_extents) + */ +int ceph_extent_to_file(struct ceph_file_layout *l, + u64 objno, u64 objoff, u64 objlen, + struct ceph_file_extent **file_extents, + u32 *num_file_extents) +{ + u32 stripes_per_object = l->object_size / l->stripe_unit; + u64 blockno; /* which su */ + 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 i = 0; + + if (!objlen) { + *file_extents = NULL; + *num_file_extents = 0; + return 0; + } + + *num_file_extents = DIV_ROUND_UP_ULL(objoff + objlen, l->stripe_unit) - + DIV_ROUND_DOWN_ULL(objoff, l->stripe_unit); + *file_extents = kmalloc_array(*num_file_extents, sizeof(**file_extents), + GFP_NOIO); + if (!*file_extents) + return -ENOMEM; + + div_u64_rem(objoff, l->stripe_unit, &blockoff); + while (objlen) { + u64 off, len; + + objsetno = div_u64_rem(objno, l->stripe_count, &stripepos); + stripeno = div_u64(objoff, l->stripe_unit) + + objsetno * stripes_per_object; + blockno = stripeno * l->stripe_count + stripepos; + off = blockno * l->stripe_unit + blockoff; + len = min_t(u64, objlen, l->stripe_unit - blockoff); + + (*file_extents)[i].fe_off = off; + (*file_extents)[i].fe_len = len; + + blockoff = 0; + objoff += len; + objlen -= len; + i++; + } + + BUG_ON(i != *num_file_extents); + return 0; +} +EXPORT_SYMBOL(ceph_extent_to_file); |