Fix RedHat bug 329431
The idea here is separate "conscious" from "unconscious" flushes.
Conscious flushes are those due to a fsync() or close(). Unconscious
ones are flushes that occur as a side effect of some other operation or
due to memory pressure.
Currently, when an error occurs during an unconscious flush (ENOSPC or
EIO), we toss out the page and don't preserve that error to report to
the user when a conscious flush occurs. If after the unconscious flush,
there are no more dirty pages for the inode, the conscious flush will
simply return success even though there were previous errors when writing
out pages. This can lead to data corruption.
The easiest way to reproduce this is to mount up a CIFS share that's
very close to being full or where the user is very close to quota. mv
a file to the share that's slightly larger than the quota allows. The
writes will all succeed (since they go to pagecache). The mv will do a
setattr to set the new file's attributes. This calls
filemap_write_and_wait,
which will return an error since all of the pages can't be written out.
Then later, when the flush and release ops occur, there are no more
dirty pages in pagecache for the file and those operations return 0. mv
then assumes that the file was written out correctly and deletes the
original.
CIFS already has a write_behind_rc variable where it stores the results
from earlier flushes, but that value is only reported in cifs_close.
Since the VFS ignores the return value from the release operation, this
isn't helpful. We should be reporting this error during the flush
operation.
This patch does the following:
1) changes cifs_fsync to use filemap_write_and_wait and cifs_flush and also
sync to check its return code. If it returns successful, they then check
the value of write_behind_rc to see if an earlier flush had reported any
errors. If so, they return that error and clear write_behind_rc.
2) sets write_behind_rc in a few other places where pages are written
out as a side effect of other operations and the code waits on them.
3) changes cifs_setattr to only call filemap_write_and_wait for
ATTR_SIZE changes.
4) makes cifs_writepages accurately distinguish between EIO and ENOSPC
errors when writing out pages.
Some simple testing indicates that the patch works as expected and that
it fixes the reproduceable known problem.
Acked-by: Dave Kleikamp <shaggy@austin.rr.com>
Signed-off-by: Jeff Layton <jlayton@redhat.com>
Signed-off-by: Steve French <sfrench@us.ibm.com>
Caused by unneeded reopen during reconnect while spinlock held.
Fixes kernel bugzilla bug #7903
Thanks to Lin Feng Shen for testing this, and Amit Arora for
some nice problem determination to narrow this down.
Acked-by: Dave Kleikamp <shaggy@us.ibm.com>
Signed-off-by: Steve French <sfrench@us.ibm.com>
nfsd is passing null nameidata (probably the only one doing that)
on call to create - cifs was missing one check for this.
Note that running nfsd over a cifs mount requires specifying fsid on
the nfs exports entry and requires mounting cifs with serverino mount
option.
Signed-off-by: Steve French <sfrench@us.ibm.com>
We had a customer report that attempting to make CIFS mount with a null
username (i.e. doing an anonymous mount) doesn't work. Looking through the
code, it looks like CIFS expects a NULL username from userspace in order
to trigger an anonymous mount. The mount.cifs code doesn't seem to ever
pass a null username to the kernel, however.
It looks also like the kernel can take a sec=none option, but it only seems
to look at it if the username is already NULL. This seems redundant and
effectively makes sec=none useless.
The following patch makes sec=none force an anonymous mount.
Signed-off-by: Steve French <sfrench@us.ibm.com>
When CIFS Unix Extensions are negotiated we get the Unix uid and gid
owners of the file from the server (on the Unix Query Path Info
levels), but if the server's uids don't match the client uid's users
were having to disable the Unix Extensions (which turned off features
they still wanted). The changeset patch allows users to override uid
and/or gid for file/directory owner with a default uid and/or gid
specified at mount (as is often done when mounting from Linux cifs
client to Windows server). This changeset also displays the uid
and gid used by default in /proc/mounts (if applicable).
Also cleans up code by adding some of the missing spaces after
"if" keywords per-kernel style guidelines (as suggested by Randy Dunlap
when he reviewed the patch).
Signed-off-by: Steve French <sfrench@us.ibm.com>
in directory
Also includes first part of fix to compensate for servers which forget
to return . and .. as well as updates to changelog and cifs readme.
Signed-off-by: Steve French <sfrench@us.ibm.com>
disabled. Also set mode, uid, gid better on mkdir and create for the
case when Unix Extensions is not enabled and setuids is enabled. This is
necessary to fix the hole in which chown could be allowed for non-root
users in some cases if root mounted, and also to display the mode and uid
properly in some cases.
Signed-off-by: Steve French <sfrench@us.ibm.com>
New cifs_writepages routine was not updated bytes written in cifs stats.
Also added ability to clear /proc/fs/cifs/Stats by writing (0 or 1) to it.
Signed-off-by: Steve French <sfrench@us.ibm.com>
over the wire (to help the case when applications break with cifs mandatory
lock behavior. Add part one of mount option for requesting case
insensitive path name matching.
Signed-off-by: Steve French (sfrench@us.ibm.com)
There's no longer a reason to document the obsolete BK usage.
Signed-off-by: Adrian Bunk <bunk@stusta.de>
Cc: Jeff Garzik <jgarzik@pobox.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
.. since it can be due to pending kill.
Update readme information to better describe cifs umount
Signed-off-by: Steve French (sfrench@us.ibm.com)
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
For handling seven special characters that shells use for filenames.
This first parts implements conversions from Unicode.
Signed-off-by: Steve French
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
Initial git repository build. I'm not bothering with the full history,
even though we have it. We can create a separate "historical" git
archive of that later if we want to, and in the meantime it's about
3.2GB when imported into git - space that would just make the early
git days unnecessarily complicated, when we don't have a lot of good
infrastructure for it.
Let it rip!
Steve French