From db2196a58939c0b75b9b7ea5ab1fec4081d48661 Mon Sep 17 00:00:00 2001 From: Ilya Dryomov Date: Tue, 16 Jan 2018 12:15:02 +0100 Subject: libceph: eliminate overflows in ceph_calc_file_object_mapping() bl, stripeno and objsetno should be u64 -- otherwise large enough files get corrupted. How large depends on file layout: - 4M-objects layout (default): any file over 16P - 64K-objects layout (smallest possible object size): any file over 512T Only CephFS is affected, rbd doesn't use ceph_calc_file_object_mapping() yet. Fortunately, CephFS has a max_file_size configurable, the default for which is way below both of the above numbers. Reimplement the logic from scratch with no layout validation -- it's done on the MDS side. Signed-off-by: Ilya Dryomov Reviewed-by: Alex Elder --- net/ceph/osdmap.c | 88 ++++++++++++++++++------------------------------------- 1 file changed, 28 insertions(+), 60 deletions(-) (limited to 'net/ceph/osdmap.c') diff --git a/net/ceph/osdmap.c b/net/ceph/osdmap.c index 0da27c66349a..3faa9e701518 100644 --- a/net/ceph/osdmap.c +++ b/net/ceph/osdmap.c @@ -2141,72 +2141,40 @@ bool ceph_osds_changed(const struct ceph_osds *old_acting, } /* - * calculate file layout from given offset, length. - * fill in correct oid, logical length, and object extent - * offset, length. + * 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). * - * for now, we write only a single su, until we can - * pass a stride back to the caller. + * 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 */ -int ceph_calc_file_object_mapping(struct ceph_file_layout *layout, +int ceph_calc_file_object_mapping(struct ceph_file_layout *l, u64 off, u64 len, - u64 *ono, - u64 *oxoff, u64 *oxlen) -{ - u32 osize = layout->object_size; - u32 su = layout->stripe_unit; - u32 sc = layout->stripe_count; - u32 bl, stripeno, stripepos, objsetno; - u32 su_per_object; - u64 t, su_offset; - - dout("mapping %llu~%llu osize %u fl_su %u\n", off, len, - osize, su); - if (su == 0 || sc == 0) - goto invalid; - su_per_object = osize / su; - if (su_per_object == 0) - goto invalid; - dout("osize %u / su %u = su_per_object %u\n", osize, su, - su_per_object); - - if ((su & ~PAGE_MASK) != 0) - goto invalid; - - /* bl = *off / su; */ - t = off; - do_div(t, su); - bl = t; - dout("off %llu / su %u = bl %u\n", off, su, bl); - - stripeno = bl / sc; - stripepos = bl % sc; - objsetno = stripeno / su_per_object; - - *ono = objsetno * sc + stripepos; - dout("objset %u * sc %u = ono %u\n", objsetno, sc, (unsigned int)*ono); - - /* *oxoff = *off % layout->fl_stripe_unit; # offset in su */ - t = off; - su_offset = do_div(t, su); - *oxoff = su_offset + (stripeno % su_per_object) * su; + u64 *objno, u64 *objoff, u64 *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 */ - /* - * Calculate the length of the extent being written to the selected - * object. This is the minimum of the full length requested (len) or - * the remainder of the current stripe being written to. - */ - *oxlen = min_t(u64, len, su - su_offset); + 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); - dout(" obj extent %llu~%llu\n", *oxoff, *oxlen); - return 0; + *objno = objsetno * l->stripe_count + stripepos; + *objoff = objsetpos * l->stripe_unit + blockoff; + *xlen = min_t(u64, len, l->stripe_unit - blockoff); -invalid: - dout(" invalid layout\n"); - *ono = 0; - *oxoff = 0; - *oxlen = 0; - return -EINVAL; + return 0; } EXPORT_SYMBOL(ceph_calc_file_object_mapping); -- cgit v1.2.3