Gitweb: https://sourceware.org/git/?p=lvm2.git;a=commitdiff;h=14b1e5270dbca71870a79b... Commit: 14b1e5270dbca71870a79b37d6614e2cb96b180f Parent: 4c88c4626d9870d4fa146f7596a37853cf965a39 Author: Alasdair G Kergon agk@redhat.com AuthorDate: Fri Dec 8 01:11:34 2017 +0000 Committer: Alasdair G Kergon agk@redhat.com CommitterDate: Fri Dec 8 01:18:46 2017 +0000

format_text: Use explicit alignment in wrapping calc.

Expand out the metadata wrapping calculations to prepare to support a larger alignment.

The current alignment is 512 bytes so (mdac_area_start + rlocn->offset) % alignment is zero. --- lib/format_text/format-text.c | 29 +++++++++++++++++------------ lib/format_text/layout.h | 1 + 2 files changed, 18 insertions(+), 12 deletions(-)

diff --git a/lib/format_text/format-text.c b/lib/format_text/format-text.c index 09ce693..c96fad9 100644 --- a/lib/format_text/format-text.c +++ b/lib/format_text/format-text.c @@ -472,19 +472,24 @@ static struct raw_locn *_find_vg_rlocn(struct device_area *dev_area, /* * Determine offset for uncommitted metadata */ -static uint64_t _next_rlocn_offset(struct raw_locn *rlocn, - struct mda_header *mdah) +static uint64_t _next_rlocn_offset(struct raw_locn *rlocn, struct mda_header *mdah, uint64_t mdac_area_start, uint64_t alignment) { + uint64_t new_start_offset; + if (!rlocn) /* Find an empty slot */ /* FIXME Assume only one VG per mdah for now */ - return MDA_HEADER_SIZE; + return alignment; + + /* Calculate new start position within buffer rounded up to absolute alignment */ + new_start_offset = rlocn->offset + rlocn->size + + (alignment - (mdac_area_start + rlocn->offset + rlocn->size) % alignment);

- /* Start of free space - round up to next sector; circular */ - return ((rlocn->offset + rlocn->size + - (SECTOR_SIZE - rlocn->size % SECTOR_SIZE) - - MDA_HEADER_SIZE) % (mdah->size - MDA_HEADER_SIZE)) - + MDA_HEADER_SIZE; + /* If new location is beyond the end of the buffer, wrap around back to start of circular buffer */ + if (new_start_offset > mdah->size - MDA_HEADER_SIZE) + new_start_offset -= (mdah->size - MDA_HEADER_SIZE); + + return new_start_offset; }

static int _raw_holds_vgname(struct format_instance *fid, @@ -643,9 +648,6 @@ static int _vg_write_raw(struct format_instance *fid, struct volume_group *vg, if (!(mdah = raw_read_mda_header(fid->fmt, &mdac->area, mda_is_primary(mda)))) goto_out;

- rlocn = _find_vg_rlocn(&mdac->area, mdah, mda_is_primary(mda), old_vg_name ? : vg->name, &noprecommit); - mdac->rlocn.offset = _next_rlocn_offset(rlocn, mdah); - if (!fidtc->raw_metadata_buf && !(fidtc->raw_metadata_buf_size = text_vg_export_raw(vg, "", &fidtc->raw_metadata_buf))) { @@ -653,6 +655,9 @@ static int _vg_write_raw(struct format_instance *fid, struct volume_group *vg, goto out; }

+ rlocn = _find_vg_rlocn(&mdac->area, mdah, mda_is_primary(mda), old_vg_name ? : vg->name, &noprecommit); + + mdac->rlocn.offset = _next_rlocn_offset(rlocn, mdah, mdac->area.start, MDA_ORIGINAL_ALIGNMENT); mdac->rlocn.size = fidtc->raw_metadata_buf_size;

if (mdac->rlocn.offset + mdac->rlocn.size > mdah->size) @@ -683,7 +688,7 @@ static int _vg_write_raw(struct format_instance *fid, struct volume_group *vg, goto_out;

if (new_wrap) { - log_debug_metadata("Writing metadata to %s at %" PRIu64 " len %" PRIu64, + log_debug_metadata("Writing wrapped metadata to %s at %" PRIu64 " len %" PRIu64, dev_name(mdac->area.dev), mdac->area.start + MDA_HEADER_SIZE, new_wrap);

diff --git a/lib/format_text/layout.h b/lib/format_text/layout.h index c88812f..1746b9c 100644 --- a/lib/format_text/layout.h +++ b/lib/format_text/layout.h @@ -102,6 +102,7 @@ struct mda_context { #define MDA_HEADER_SIZE 512 #define LVM2_LABEL "LVM2 001" #define MDA_SIZE_MIN (8 * (unsigned) lvm_getpagesize()) +#define MDA_ORIGINAL_ALIGNMENT 512 /* Original alignment used for start of VG metadata content */

int vgname_from_mda(const struct format_type *fmt, struct mda_header *mdah, int primary_mda, struct device_area *dev_area, struct lvmcache_vgsummary *vgsummary,