git: hammer2 - Finally fix the 'file winds up with some zeros' bug
dillon at crater.dragonflybsd.org
Tue Nov 19 12:06:32 PST 2019
Author: Matthew Dillon <dillon at apollo.backplane.com>
Date: Tue Nov 19 12:02:39 2019 -0800
hammer2 - Finally fix the 'file winds up with some zeros' bug
* Fix this bug, which has been reported several times this year
but until nikita's hands-on I couldn't find it.
* The bug occurs when H2 must transition from the 512 bytes of
file data directly embedded in the inode to a block table as
a file grows past 512 bytes.
Basically what happens is that the buffer cache buffer holding
the data in-transition can get lost.
The result is that the first write() that overlaps seek offset
512 in a small file can sometimes cause the prior data at the
start of the file to be lost.
* To solve the problem the buffer is now held across the transition
and explicitly dirtied to force it to be flushed to the now-
realized block table.
Reported-by: nikita and several others this year
Summary of changes:
sys/vfs/hammer2/hammer2_vnops.c | 30 +++++++++++++++++++++++++-----
1 file changed, 25 insertions(+), 5 deletions(-)
DragonFly BSD source repository
More information about the Commits