----- Original Message ----- > This is a revised version of the patches required to properly fix the > fallocate quota issue described in bz1174295 > > patch1: This patch supplies gfs2_quota_check() with the number of blocks > the caller intends to allocate in the current operation, resulting > in a more accurate quota check. > > patch2: gfs2_quota_check() and gfs2_inplace_reserve() return the number > of blocks available subject to quota limits and rgrp size > respectively. The difference from previous versions of this patch > is that we return the available blocks even on success. > > patch3: The fallocate() function uses the features of patch2 to determine > how many total blocks are available for allocation and uses them > right away, instead of guessing inefficiently. > > The behavior of quota enforcement is altered by this patchset. > i. Quotas are exceeded (a warning message is also issued to syslog) before > the actual usage blocks exceed the imposed limit. In fact, the actual > usage can never exceed the limit. Whenever it is determined that the > completion of an operation will cause a quota to exceed its limit, such > an operation is aborted with -EDQUOT and a 'quota exceeded' message is > dispatched. > ii. The gfs2_write_calc_reserv()/calc_max_reserv() functions are used to > map between available blocks and the data bytes that can be written > using them. Typically, for large files, some blocks are used up for > metadata and only the remaining blocks can be used for data. Example: > To write only a handful of bytes that would easily fit in one block, we > might have to allocate an extra bunch of intermediate metadata blocks. > If we had only 1 block left in our allotted quota, this operation would > likely fail. > > The functions mentioned in ii. are not very efficient. They always compute > the worst case number of extra blocks required and it is often the case that > not all those extra blocks are used. We need to find a better algorithm to > get a tighter estimate on the blocks needed for a given number of bytes. > > I've run some basic tests and things seem to be holding up. The failing case > in bz1174295 is fixed using this patchset. I'll do test build and pass it on > to Nate to test with. > > Abhi Das (3): > gfs2: perform quota checks against allocation parameters > gfs2: allow quota_check and inplace_reserve to return available blocks > gfs2: allow fallocate to max out quotas/fs efficiently > > fs/gfs2/aops.c | 6 ++--- > fs/gfs2/bmap.c | 2 +- > fs/gfs2/file.c | 75 > ++++++++++++++++++++++++++++++++++++++------------------ > fs/gfs2/incore.h | 3 ++- > fs/gfs2/inode.c | 18 ++++++++------ > fs/gfs2/quota.c | 40 ++++++++++++++++++++++-------- > fs/gfs2/quota.h | 8 +++--- > fs/gfs2/rgrp.c | 12 +++++++-- > fs/gfs2/rgrp.h | 6 +++-- > fs/gfs2/xattr.c | 2 +- > 10 files changed, 117 insertions(+), 55 deletions(-) > > -- > 1.8.1.4
Looks good to me. ACK to the series. Regards, Bob Peterson Red Hat File Systems
