Gitweb: https://sourceware.org/git/?p=lvm2.git;a=commitdiff;h=2db67a8ea09a6f1073583e... Commit: 2db67a8ea09a6f1073583e135bfb7b66228d3526 Parent: 46393bfca0692ebddbecdfb1f3b8699c3caa4f16 Author: Alasdair G Kergon agk@redhat.com AuthorDate: Mon Dec 11 17:08:29 2017 +0000 Committer: Alasdair G Kergon agk@redhat.com CommitterDate: Mon Dec 11 17:08:29 2017 +0000

format_text: Move metadata size checking into separate fn.

Move checks into _metadata_fits_into_buffer() and add macro for alignment. --- lib/format_text/format-text.c | 55 +++++++++++++++++++++++++++++++--------- 1 files changed, 42 insertions(+), 13 deletions(-)

diff --git a/lib/format_text/format-text.c b/lib/format_text/format-text.c index 0dbab11..881fd4d 100644 --- a/lib/format_text/format-text.c +++ b/lib/format_text/format-text.c @@ -37,6 +37,12 @@ #include <dirent.h> #include <ctype.h>

+/* + * Round up offset within buffer to next location that is an exact multiple of alignment. + * (We shouldn't assume the start of the metadata area was aligned the same way when it was created.) + */ +#define ALIGN_ABSOLUTE(offset, buffer_start, alignment) ((offset) + (alignment) - UINT64_C(1) - ((buffer_start) + (offset) + (alignment) - UINT64_C(1)) % (alignment)) + static struct format_instance *_text_create_text_instance(const struct format_type *fmt, const struct format_instance_ctx *fic);

@@ -615,6 +621,34 @@ static struct volume_group *_vg_read_precommit_raw(struct format_instance *fid, return vg; }

+static int _metadata_fits_into_buffer(struct mda_context *mdac, struct mda_header *mdah, + struct raw_locn *rlocn, uint64_t new_wrap) +{ + uint64_t old_wrap = 0; /* Amount of wrap around in existing metadata */ + uint64_t new_end; /* The end location of the new metadata */ + + /* Do we have existing metadata that ends beyond the end of the buffer? */ + if (rlocn && (rlocn->offset + rlocn->size > mdah->size)) + old_wrap = (rlocn->offset + rlocn->size) - mdah->size; + + new_end = new_wrap ? new_wrap + MDA_HEADER_SIZE : + mdac->rlocn.offset + mdac->rlocn.size; + + /* If both wrap around, there's necessarily overlap */ + if (new_wrap && old_wrap) + return_0; + + /* If either wraps around, does the new end fall beyond the old start? */ + if (rlocn && (new_wrap || old_wrap) && (new_end > rlocn->offset)) + return_0; + + /* Does the total amount of metadata, old and new, fit inside the buffer? */ + if (MDA_HEADER_SIZE + (rlocn ? rlocn->size : 0) + mdac->rlocn.size >= mdah->size) + return_0; + + return 1; +} + static int _vg_write_raw(struct format_instance *fid, struct volume_group *vg, struct metadata_area *mda) { @@ -624,7 +658,7 @@ static int _vg_write_raw(struct format_instance *fid, struct volume_group *vg, struct mda_header *mdah; struct pv_list *pvl; int r = 0; - uint64_t new_wrap = 0, old_wrap = 0, new_end; + uint64_t new_wrap; /* Number of bytes of new metadata that wrap around to start of buffer */ int found = 0; int noprecommit = 0; const char *old_vg_name = NULL; @@ -657,21 +691,16 @@ static int _vg_write_raw(struct format_instance *fid, struct volume_group *vg,

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;

+ mdac->rlocn.offset = _next_rlocn_offset(rlocn, mdah, mdac->area.start, MDA_ORIGINAL_ALIGNMENT); + if (mdac->rlocn.offset + mdac->rlocn.size > mdah->size) new_wrap = (mdac->rlocn.offset + mdac->rlocn.size) - mdah->size; + else + new_wrap = 0;

- if (rlocn && (rlocn->offset + rlocn->size > mdah->size)) - old_wrap = (rlocn->offset + rlocn->size) - mdah->size; - - new_end = new_wrap ? new_wrap + MDA_HEADER_SIZE : - mdac->rlocn.offset + mdac->rlocn.size; - - if ((new_wrap && old_wrap) || - (rlocn && (new_wrap || old_wrap) && (new_end > rlocn->offset)) || - (MDA_HEADER_SIZE + (rlocn ? rlocn->size : 0) + mdac->rlocn.size >= mdah->size)) { + if (!_metadata_fits_into_buffer(mdac, mdah, rlocn, new_wrap)) { log_error("VG %s metadata on %s (" FMTu64 " bytes) too large for circular buffer (" FMTu64 " bytes with " FMTu64 " used)", vg->name, dev_name(mdac->area.dev), mdac->rlocn.size, mdah->size - MDA_HEADER_SIZE, rlocn ? rlocn->size : 0); goto out; @@ -1263,8 +1292,8 @@ int vgname_from_mda(const struct format_type *fmt, (char *)&vgsummary->vgid);

if (mda_free_sectors) { - current_usage = (rlocn->size + SECTOR_SIZE - UINT64_C(1)) - - (rlocn->size + SECTOR_SIZE - UINT64_C(1)) % SECTOR_SIZE; + current_usage = ALIGN_ABSOLUTE(rlocn->size, 0, MDA_ORIGINAL_ALIGNMENT); + buffer_size = mdah->size - MDA_HEADER_SIZE;

if (current_usage * 2 >= buffer_size)