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format_text: More refactoring of metadata offset calcs

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This commit is contained in:
Alasdair G Kergon 2017-12-12 18:46:25 +00:00
parent 4002f5e206
commit 643df602c7
1 changed files with 23 additions and 7 deletions
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30
lib/format_text/format-text.c
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@ -482,15 +482,24 @@ static struct raw_locn *_find_vg_rlocn(struct device_area *dev_area,
*/
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;
uint64_t old_end, new_start_offset;
int old_wrapped = 0; /* Does the old metadata wrap around? */
if (!rlocn)
/* Find an empty slot */
/* FIXME Assumes only one VG per mdah for now */
return alignment;
/* First find the end of the old metadata */
old_end = rlocn->offset + rlocn->size;
if (old_end > mdah->size) {
old_wrapped = 1;
old_end -= (mdah->size - MDA_HEADER_SIZE);
}
/* Calculate new start position relative to start of buffer rounded up to absolute alignment */
new_start_offset = ALIGN_ABSOLUTE(rlocn->offset + rlocn->size, mdac_area_start, alignment);
new_start_offset = ALIGN_ABSOLUTE(old_end, mdac_area_start, alignment);
/* If new location is beyond the end of the buffer, wrap around back to start of circular buffer */
if (new_start_offset >= mdah->size)
@ -626,16 +635,23 @@ static int _metadata_fits_into_buffer(struct mda_context *mdac, struct mda_heade
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 */
uint64_t old_end = 0; /* The (byte after the) end of the existing metadata */
uint64_t new_end; /* The (byte after the) end of the new metadata */
uint64_t old_start = 0; /* The start of the existing metadata */
uint64_t new_start = mdac->rlocn.offset; /* The proposed start of the new metadata */
/* 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;
/* Does the existing metadata wrap around the end of the buffer? */
/* If there's existing metadata, set old_start, old_end and old_wrap. */
if (rlocn) {
if (rlocn->offset + rlocn->size > mdah->size)
old_wrap = (rlocn->offset + rlocn->size) - mdah->size;
old_start = rlocn->offset;
old_end = old_start + rlocn->size;
/* Does the existing metadata wrap around the end of the buffer? */
if (old_end > mdah->size)
old_wrap = old_end - mdah->size;
}
new_end = new_wrap ? new_wrap + MDA_HEADER_SIZE : (mdac->rlocn.offset + mdac->rlocn.size);
@ -649,7 +665,7 @@ static int _metadata_fits_into_buffer(struct mda_context *mdac, struct mda_heade
return 1;
/* If either wraps around, there's overlap if the new end falls beyond the old start */
if ((new_wrap || old_wrap) && (new_end > rlocn->offset))
if ((new_wrap || old_wrap) && (new_end > old_start))
return_0;
return 1;