9371e3e...
by
Artem Bityutskiy <email address hidden>
Bmap: sync with the latest bmap-tools
This patch syncs MIC's copy of BmapCreate with the latest contents of the
bmap-tools project. The reason for syncing is to fix DEVT-139. The bugreport
tells that MIC cannot generate the bmap file when the image resides on tmpfs.
And now this is fixed.
We also re-named the Fiemap module to Filemap, because now this module supports
both FIEMAP ioctl and the SEEK_HOLE method. Here is some more description from
the bmap-tools release notes.
"
Make 'bmaptool create' (and hence, the BmapCreate module) work with the
"tmpfs" file-system. This file-system does not, unfortunately, support the
"FIEMAP" ioctl, but it supports the "SEEK_HOLE" option of the "lseek" system
call, which can also be used to find where the holes are. In this release we
have implemented support for "SEEK_HOLE" to cover tmpfs. Generally, FIEMAP
is faster than "SEEK_HOLE" for large files, so we always try to start with
using FIEMAP, and if it is not supported, we fall-back to using "SEEK_HOLE".
Therefore, the "Fiemap" module was re-named to "Filemap", since it is now
supports more than just the FIEMAP ioctl.
Unfortunately, the SEEK_HOLE method requires the directory where the image
resides to be accessible for writing, because in current implementation we
need to create a temporary file there for a short time. The temporary file
is used to detect whether SEEK_HOLE is really implemented, or the system
just fakes it by always returning EOF.
"
