[Unionfs] [ANNOUNCE] Unionfs 2.0 releases for 2.6.9--2.6.22
Erez Zadok
ezk at cs.sunysb.edu
Sat Jul 14 14:26:47 EDT 2007
The following new releases of Unionfs 2.0 are now available on
<http://unionfs.filesystems.org/>
linux-2.6.22.1-u2.diff
linux-2.6.21.6-u2.diff
linux-2.6.20.14-u4.diff
linux-2.6.19.7-u4.diff
linux-2.6.18.8-u4.diff
linux-2.6.9.u2.diff
There's only one change in these releases from the previous set: a VERY
important bug fix to a NULL pointer dereference inside unionfs_readpage.
If you use Unionfs with tmpfs or vfat, this affects you.
Details:
In do_unionfs_readpage, we used to call the lower file system's
->readpage. However, some file systems (e.g., tmpfs and vfat) don't
implement ->readpage, causing a NULL pointer dereference under *certain*
conditions. The oops does not happen always, but esp. under severe
memory pressure when pages that existed in memory before got flushed and
had to be re-gotten. This fix reimplements do_unionfs_readpage using
vfs_read, which makes the code simpler and more reliable, as we depend
on the VFS to do most of the hard work.
As usual, feel free to report all problems you find to
<https://bugzilla.filesystems.org/>
Enjoy.
Erez, on behalf of the Unionfs team.
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