| Message ID | 20180228131315.30194-1-mreitz@redhat.com |
|---|---|
| Headers | show |
| Series | block/file-posix: Fix fully preallocated truncate | expand |
On 02/28/2018 07:13 AM, Max Reitz wrote: > Fully preallocated truncation has a 50 % chance of working on images > files over file-posix. It works if $SIZE % 4G < 2G, and it fails > otherwise. To make things even more interesting, often you would not > even notice because qemu reported success even though it did nothing > (because after the successful lseek(), errno was still 0, so when the > file-posix driver tried to return a negative error code, it actually > reported success). > > This issue is fixed by patch 1 in this series. Thanks to Daniel for > reporting! > > > Max Reitz (2): > block/file-posix: Fix fully preallocated truncate > iotests: Test preallocated truncate of 2G image Good catch. Series: Reviewed-by: Eric Blake <eblake@redhat.com> gluster.c has similar code, but it assigns glfs_lseek() to an int64_t, so it does not have the bug.
On 2018-02-28 14:13, Max Reitz wrote: > Fully preallocated truncation has a 50 % chance of working on images > files over file-posix. It works if $SIZE % 4G < 2G, and it fails > otherwise. To make things even more interesting, often you would not > even notice because qemu reported success even though it did nothing > (because after the successful lseek(), errno was still 0, so when the > file-posix driver tried to return a negative error code, it actually > reported success). > > This issue is fixed by patch 1 in this series. Thanks to Daniel for > reporting! > > > Max Reitz (2): > block/file-posix: Fix fully preallocated truncate > iotests: Test preallocated truncate of 2G image > > block/file-posix.c | 5 +++-- > tests/qemu-iotests/106 | 24 ++++++++++++++++++++++++ > tests/qemu-iotests/106.out | 10 ++++++++++ > 3 files changed, 37 insertions(+), 2 deletions(-) Applied to my block tree... (*cough* *cough* -- I'm the worst when it comes to keeping track of my own patches.) Max