shaba/lvm2
1
0
Fork 0
mirror of git://sourceware.org/git/lvm2.git synced 2024-12-21 13:34:40 +03:00
Code Releases Activity

Improve the discard documentation. Also improve discard code in

Browse Source 
pv_manip.c to properly account for case when pe_start=0 and the first
physical extent is to be released (currently skip the first extent to
avoid discarding the PV label).
This commit is contained in:
Mike Snitzer 2011-04-13 18:26:39 +00:00
parent 727373c176
commit ffcb1b9c2c
4 changed files with 31 additions and 20 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

2
WHATS_NEW
View File

@ -1,7 +1,7 @@
Version 2.02.85 -
===================================
Add "devices/issue_discards" to lvm.conf.
Issue discards on lvremove if enabled and both storage and kernel have support.
Issue discards on lvremove, lvreduce, etc if enabled and supported.
Fix incorrect tests for dm_snprintf() failure.
Fix some unmatching sign comparation gcc warnings in the code.
Allow lv_extend() to work on zero length intrinsically layered LVs.

12
doc/example.conf.in
View File

@ -152,11 +152,15 @@ devices {
# pv_min_size = 2048
pv_min_size = 512
# Issue discards to an LV's underlying PV(s) when the LV is removed.
# Discards inform the storage that a region is no longer in use. If set
# Issue discards to a logical volumes's underlying physical volume(s) when
# the logical volume is no longer using the physical volumes' space (e.g.
# lvremove, lvreduce, etc). Discards inform the storage that a region is
# no longer in use. Storage that supports discards advertise the protocol
# specific way discards should be issued by the kernel (TRIM, UNMAP, or
# WRITE SAME with UNMAP bit set). Not all storage will support or benefit
# from discards but SSDs and thinly provisioned LUNs generally do. If set
# to 1, discards will only be issued if both the storage and kernel provide
# support. Not all storage will support or benefit from discards but SSDs
# or thinly provisioned LUNs generally do.
# support.
# 1 enables; 0 disables.
issue_discards = 0
}

24
lib/metadata/pv_manip.c
View File

@ -191,9 +191,9 @@ struct pv_segment *assign_peg_to_lvseg(struct physical_volume *pv,
int release_pv_segment(struct pv_segment *peg, uint32_t area_reduction)
{
uint64_t discard_offset;
uint64_t discard_offset_sectors;
uint64_t pe_start = peg->pv->pe_start;
uint32_t discard_area_reduction = area_reduction;
uint64_t discard_area_reduction = area_reduction;
if (!peg->lvseg) {
log_error("release_pv_segment with unallocated segment: "
@ -209,16 +209,20 @@ int release_pv_segment(struct pv_segment *peg, uint32_t area_reduction)
"devices/issue_discards", DEFAULT_ISSUE_DISCARDS) &&
dev_discard_max_bytes(peg->pv->fmt->cmd->sysfs_dir, peg->pv->dev) &&
dev_discard_granularity(peg->pv->fmt->cmd->sysfs_dir, peg->pv->dev)) {
if (!pe_start) {
/* skip the first extent */
pe_start = peg->pv->vg->extent_size;
discard_offset_sectors = (peg->pe + peg->lvseg->area_len - area_reduction) *
peg->pv->vg->extent_size + pe_start;
if (!discard_offset_sectors) {
/*
* pe_start=0 and the PV's first extent contains the label.
* Must skip past the first extent.
*/
discard_offset_sectors = peg->pv->vg->extent_size;
discard_area_reduction--;
}
discard_offset = peg->pe + peg->lvseg->area_len - area_reduction;
discard_offset = (discard_offset * peg->pv->vg->extent_size) + pe_start;
log_debug("Discarding %" PRIu32 " extents offset %" PRIu64 " sectors on %s.",
discard_area_reduction, discard_offset, dev_name(peg->pv->dev));
if (!dev_discard_blocks(peg->pv->dev, discard_offset << SECTOR_SHIFT,
log_debug("Discarding %" PRIu64 " extents offset %" PRIu64 " sectors on %s.",
discard_area_reduction, discard_offset_sectors, dev_name(peg->pv->dev));
if (discard_area_reduction &&
!dev_discard_blocks(peg->pv->dev, discard_offset_sectors << SECTOR_SHIFT,
discard_area_reduction * peg->pv->vg->extent_size * SECTOR_SIZE))
return_0;
}

13
man/lvm.conf.5.in
View File

@ -181,11 +181,14 @@ ignore devices smaller than 2MB (i.e. floppy drives):
pv_min_size = 2048
.IP
\fBissue_discards\fP \(em
Issue discards to an LV's underlying PV(s) when the LV is removed. Discards
inform the storage that a region is no longer in use. If set to 1, discards will
only be issued if both the storage and kernel provide support. Not all storage
will support or benefit from discards but SSDs or thinly provisioned LUNs
generally do.
Issue discards to a logical volumes's underlying physical volume(s) when the
logical volume is no longer using the physical volumes' space (e.g. lvremove,
lvreduce, etc). Discards inform the storage that a region is no longer in use.
Storage that supports discards advertise the protocol specific way discards
should be issued by the kernel (TRIM, UNMAP, or WRITE SAME with UNMAP bit set).
Not all storage will support or benefit from discards but SSDs and thinly
provisioned LUNs generally do. If set to 1, discards will only be issued if
both the storage and kernel provide support.
.IP
.TP
\fBallocation\fP \(em Space allocation policies