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c3702afa8c
Currently, the FBSD afs_vop_putpages uses the credentials of the
current process for writing data back to the fileserver. Usually this
works, but sometimes we're being called from syncer(4), which runs as
root instead of as the user accessing the relevant file.
This means that instead of using the tokens from the user that wrote
to the relevant file, we use whatever tokens belong to uid 0. This
usually causes an EACCES error when trying to write the data back to
the fileserver, causing us to store EACCES (13) in avc->vc_error, and
possibly causing a message in the kernel log like so:
afs: failed to store file (0/13)
Since we set vc_error during these errors, this can also cause access
to the file to fail for the normal user process until vc_error is
cleared (such as when the file is closed).
To avoid this, store the credentials of the current user that
successfully opens the file for writing (in avc->cred), and use those
creds for writing back data to the fileserver. This is the same
approach that LINUX uses as of commit 70c8deab (Use user credentials
for Linux writepage()), and the NFS client code in FreeBSD itself (see
the usage of n_writecred in struct nfsnode as of 12.1-RELEASE).
Change-Id: I592d709b68d746bbdb326dfd7d012d6de829b905
Reviewed-on: https://gerrit.openafs.org/14164
Tested-by: BuildBot <buildbot@rampaginggeek.com>
Reviewed-by: Benjamin Kaduk <kaduk@mit.edu>
AFS is a distributed file system that enables users to share and access all of the files stored in a network of computers as easily as they access the files stored on their local machines. The file system is called distributed for this exact reason: files can reside on many different machines, but are available to users on every machine. OpenAFS 1.0 was originally released by IBM under the terms of the IBM Public License 1.0 (IPL10). For details on IPL10 see the LICENSE file in this directory. The current OpenAFS distribution is licensed under a combination of the IPL10 and many other licenses as granted by the relevant copyright holders. The LICENSE file in this directory contains more details, thought it is not a comprehensive statement. See INSTALL for information about building and installing OpenAFS on various platforms. See CODING for developer information and guidelines. See NEWS for recent changes to OpenAFS.