Commit graph

35183 commits

Author SHA1 Message Date
Yan, Zheng ab866549b3 ceph: drop extra open file reference in ceph_atomic_open()
ceph_atomic_open() calls ceph_open() after receiving the MDS reply.
ceph_open() grabs an extra open file reference. (The open request
already holds an open file reference)

Signed-off-by: Yan, Zheng <zheng.z.yan@intel.com>
2014-04-04 21:08:23 -07:00
Yan, Zheng 54008399dc ceph: preallocate buffer for readdir reply
Preallocate buffer for readdir reply. Limit number of entries in
readdir reply according to the buffer size.

Signed-off-by: Yan, Zheng <zheng.z.yan@intel.com>
2014-04-04 21:08:22 -07:00
Yan, Zheng cc48c3e85f ceph: don't include ceph.{file,dir}.layout vxattr in listxattr()
This avoids 'cp -a' modifying layout of new files/directories.

Signed-off-by: Yan, Zheng <zheng.z.yan@intel.com>
2014-04-04 21:07:21 -07:00
Yan, Zheng 1e5c6649ff ceph: check buffer size in ceph_vxattrcb_layout()
If buffer size is zero, return the size of layout vxattr. If buffer
size is not zero, check if it is large enough for layout vxattr.

Signed-off-by: Yan, Zheng <zheng.z.yan@intel.com>
2014-04-04 21:07:19 -07:00
Yan, Zheng 00bd8edb86 ceph: fix null pointer dereference in discard_cap_releases()
send_mds_reconnect() may call discard_cap_releases() after all
release messages have been dropped by cleanup_cap_releases()

Signed-off-by: Yan, Zheng <zheng.z.yan@intel.com>
Reviewed-by: Sage Weil <sage@inktank.com>
2014-04-04 21:07:17 -07:00
Fabian Frederick 5f75ce5781 ceph: Remove get/set acl on symlinks
Remove unsupported symlink operations.

Signed-off-by: Fabian Frederick <fabf@skynet.be>
Signed-off-by: Ilya Dryomov <ilya.dryomov@inktank.com>
2014-04-04 21:07:14 -07:00
Yan, Zheng d9ffc4f770 ceph: set mds_wanted when MDS reply changes a cap to auth cap
When adjusting caps client wants, MDS does not record caps that are
not allowed. For non-auth MDS, it does not record WR caps. So when
a MDS reply changes a non-auth cap to auth cap, client needs to set
cap's mds_wanted according to the reply.

Signed-off-by: Yan, Zheng <zheng.z.yan@intel.com>
2014-04-04 21:07:12 -07:00
Yan, Zheng eb13e832f8 ceph: use fl->fl_file as owner identifier of flock and posix lock
flock and posix lock should use fl->fl_file instead of process ID
as owner identifier. (posix lock uses fl->fl_owner. fl->fl_owner
is usually equal to fl->fl_file, but it also can be a customized
value). The process ID of who holds the lock is just for F_GETLK
fcntl(2).

The fix is rename the 'pid' fields of struct ceph_mds_request_args
and struct ceph_filelock to 'owner', rename 'pid_namespace' fields
to 'pid'. Assign fl->fl_file to the 'owner' field of lock messages.
We also set the most significant bit of the 'owner' field. MDS can
use that bit to distinguish between old and new clients.

The MDS counterpart of this patch modifies the flock code to not
take the 'pid_namespace' into consideration when checking conflict
locks.

Signed-off-by: Yan, Zheng <zheng.z.yan@intel.com>
Reviewed-by: Sage Weil <sage@inktank.com>
2014-04-04 21:07:11 -07:00
Yan, Zheng eb70c0ce4e ceph: forbid mandatory file lock
Signed-off-by: Yan, Zheng <zheng.z.yan@intel.com>
2014-04-04 21:07:09 -07:00
Yan, Zheng 0e8e95d6d7 ceph: use fl->fl_type to decide flock operation
VFS does not directly pass flock's operation code to filesystem's
flock callback. It translates the operation code to the form how
posix lock's parameters are presented.

Signed-off-by: Yan, Zheng <zheng.z.yan@intel.com>
2014-04-04 21:07:08 -07:00
Yan, Zheng 8c93cd610c ceph: update i_max_size even if inode version does not change
handle following sequence of events:
 - client releases a inode with i_max_size > 0. The release message
   is queued. (is not sent to the auth MDS)
 - a 'lookup' request reply from non-auth MDS returns the same inode.
 - client opens the inode in write mode. The version of inode trace
   in 'open' request reply is equal to the cached inode's version.
 - client requests new max size. The MDS ignores the request because
   it does not affect client's write range

Signed-off-by: Yan, Zheng <zheng.z.yan@intel.com>
Reviewed-by: Sage Weil <sage@inktank.com>
2014-04-04 21:07:06 -07:00
Yan, Zheng a255060451 ceph: make sure write caps are registered with auth MDS
Only auth MDS can issue write caps to clients, so don't consider
write caps registered with non-auth MDS as valid.

Signed-off-by: Yan, Zheng <zheng.z.yan@intel.com>
2014-04-04 21:07:05 -07:00
Yan, Zheng c137a32a40 ceph: print inode number for LOOKUPINO request
Signed-off-by: Yan, Zheng <zheng.z.yan@intel.com>
Reviewed-by: Sage Weil <sage@inktank.com>
2014-04-03 10:33:54 +08:00
Yan, Zheng 19913b4eac ceph: add get_name() NFS export callback
Use the newly introduced LOOKUPNAME MDS request to connect child
inode to its parent directory.

Signed-off-by: Yan, Zheng <zheng.z.yan@intel.com>
Reviewed-by: Sage Weil <sage@inktank.com>
2014-04-03 10:33:53 +08:00
Yan, Zheng 8996f4f23d ceph: fix ceph_fh_to_parent()
ceph_fh_to_parent() returns dentry that corresponds to the 'ino' field
of struct ceph_nfs_confh. This is wrong, it should return dentry that
corresponds to the 'parent_ino' field.

Signed-off-by: Yan, Zheng <zheng.z.yan@intel.com>
Reviewed-by: Sage Weil <sage@inktank.com>
2014-04-03 10:33:53 +08:00
Yan, Zheng 9017c2ec78 ceph: add get_parent() NFS export callback
The callback uses LOOKUPPARENT MDS request to find parent.

Signed-off-by: Yan, Zheng <zheng.z.yan@intel.com>
Reviewed-by: Sage Weil <sage@inktank.com>
2014-04-03 10:33:53 +08:00
Yan, Zheng 4f32b42dca ceph: simplify ceph_fh_to_dentry()
MDS handles LOOKUPHASH and LOOKUPINO MDS requests in the same way.
So __cfh_to_dentry() is redundant.

Signed-off-by: Yan, Zheng <zheng.z.yan@intel.com>
Reviewed-by: Sage Weil <sage@inktank.com>
2014-04-03 10:33:53 +08:00
Yunchuan Wen f1fc4fee3b ceph: fscache: Wait for completion of object initialization
The object store limit needs to be updated after writing,
and this can be done provided the corresponding object has already
been initialized. Current object initialization is done asynchrously,
which introduce a race if a file is opened, then immediately followed
by a writing, the initialization may have not completed, the code will
reach the ASSERT in fscache_submit_exclusive_op() to cause kernel
bug.

Tested-by: Milosz Tanski <milosz@adfin.com>
Signed-off-by: Yunchuan Wen <yunchuanwen@ubuntukylin.com>
Signed-off-by: Min Chen <minchen@ubuntukylin.com>
Signed-off-by: Li Wang <liwang@ubuntukylin.com>
2014-04-03 10:33:53 +08:00
Yunchuan Wen 32d3e148dd ceph: fscache: Update object store limit after file writing
Synchronize object->store_limit[_l] with new inode->i_size after file writing.

Tested-by: Milosz Tanski <milosz@adfin.com>
Signed-off-by: Yunchuan Wen <yunchuanwen@ubuntukylin.com>
Signed-off-by: Min Chen <minchen@ubuntukylin.com>
Signed-off-by: Li Wang <liwang@ubuntukylin.com>
2014-04-03 10:33:53 +08:00
Yunchuan Wen 020c4bddc0 ceph: fscache: add an interface to synchronize object store limit
Add an interface to explicitly synchronize object->store_limit[_l]
with inode->i_size

Tested-by: Milosz Tanski <milosz@adfin.com>
Signed-off-by: Yunchuan Wen <yunchuanwen@ubuntukylin.com>
Signed-off-by: Min Chen <minchen@ubuntukylin.com>
Signed-off-by: Li Wang <liwang@ubuntukylin.com>
2014-04-03 10:33:53 +08:00
Sage Weil 4b58c9b19b ceph: do not set r_old_dentry_dir on link()
This is racy--we do not know whather d_parent has changed out from
underneath us because i_mutex is not held on the source inode's directory.

Also, taking this reference is useless.

Reported-by: Al Viro <viro@zeniv.linux.org.uk>
Signed-off-by: Sage Weil <sage@inktank.com>
Reviewed-by: Yan, Zheng <zheng.z.yan@intel.com>
2014-04-03 10:33:53 +08:00
Sage Weil 844d87c332 ceph: do not assume r_old_dentry[_dir] always set together
Do not assume that r_old_dentry implies that r_old_dentry_dir is also
true.  Separate out the ref cleanup and make the debugs dump behave when
it is NULL.

Signed-off-by: Sage Weil <sage@inktank.com>
Reviewed-by: Yan, Zheng <zheng.z.yan@intel.com>
2014-04-03 10:33:53 +08:00
Sage Weil 752c8bdcfe ceph: do not chain inode updates to parent fsync
The fsync(dirfd) only covers namespace operations, not inode updates.
We do not need to cover setattr variants or O_TRUNC.

Reported-by: Al Viro <viro@xeniv.linux.org.uk>
Signed-off-by: Sage Weil <sage@inktank.com>
Reviewed-by: Yan, Zheng <zheng.z.yan@intel.com>
2014-04-03 10:33:52 +08:00
Sage Weil 180061a58c ceph: avoid useless ceph_get_dentry_parent_inode() in ceph_rename()
This is just old_dir; no reason to abuse the dcache pointers.

Reported-by: Al Viro <viro.zeniv.linux.org.uk>
Signed-off-by: Sage Weil <sage@inktank.com>
Reviewed-by: Yan, Zheng <zheng.z.yan@intel.com>
2014-04-03 10:33:52 +08:00
Yan, Zheng 15289dc85b ceph: let MDS adjust readdir 'frag'
If readdir 'frag' is adjusted, readdir 'offset' should be reset.
Otherwise some dentries may be lost when readdir and fragmenting
directory happen at the some.

Another way to fix this issue is let MDS adjust readdir 'frag'.
The code that handles MDS reply reset the readdir 'offset' if
the readdir reply is different than the requested one.

Signed-off-by: Yan, Zheng <zheng.z.yan@intel.com>
2014-04-03 10:33:52 +08:00
Yan, Zheng dcd3cc05e5 ceph: fix reset_readdir()
When changing readdir postion, fi->next_offset should be set to 0
if the new postion is not in the first dirfrag.

Signed-off-by: Yan, Zheng <zheng.z.yan@intel.com>
Reviewed-by: Alex Elder <elder@linaro.org>
2014-04-03 10:33:52 +08:00
Yan, Zheng f049420607 ceph: fix ceph_dir_llseek()
Comparing offset with inode->i_sb->s_maxbytes doesn't make sense for
directory. For a fragmented directory, offset (frag_t, off) can be
larger than inode->i_sb->s_maxbytes.

At the very beginning of ceph_dir_llseek(), local variable old_offset
is initialized to parameter offset. This doesn't make sense neither.
Old_offset should be ceph_make_fpos(fi->frag, fi->next_offset).

Signed-off-by: Yan, Zheng <zheng.z.yan@intel.com>
Reviewed-by: Alex Elder <elder@linaro.org>
2014-04-03 10:33:52 +08:00
Linus Torvalds fedc1ed0f1 Merge branch 'for-linus-2' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs
Pull vfs fixes from Al Viro:
 "Switch mnt_hash to hlist, turning the races between __lookup_mnt() and
  hash modifications into false negatives from __lookup_mnt() (instead
  of hangs)"

On the false negatives from __lookup_mnt():
 "The *only* thing we care about is not getting stuck in __lookup_mnt().
  If it misses an entry because something in front of it just got moved
  around, etc, we are fine.  We'll notice that mount_lock mismatch and
  that'll be it"

* 'for-linus-2' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs:
  switch mnt_hash to hlist
  don't bother with propagate_mnt() unless the target is shared
  keep shadowed vfsmounts together
  resizable namespace.c hashes
2014-03-30 17:26:08 -07:00
Theodore Ts'o 00a1a053eb ext4: atomically set inode->i_flags in ext4_set_inode_flags()
Use cmpxchg() to atomically set i_flags instead of clearing out the
S_IMMUTABLE, S_APPEND, etc. flags and then setting them from the
EXT4_IMMUTABLE_FL, EXT4_APPEND_FL flags, since this opens up a race
where an immutable file has the immutable flag cleared for a brief
window of time.

Reported-by: John Sullivan <jsrhbz@kanargh.force9.co.uk>
Signed-off-by: "Theodore Ts'o" <tytso@mit.edu>
Cc: stable@kernel.org
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2014-03-30 17:02:06 -07:00
Al Viro 38129a13e6 switch mnt_hash to hlist
fixes RCU bug - walking through hlist is safe in face of element moves,
since it's self-terminating.  Cyclic lists are not - if we end up jumping
to another hash chain, we'll loop infinitely without ever hitting the
original list head.

[fix for dumb braino folded]

Spotted by: Max Kellermann <mk@cm4all.com>
Cc: stable@vger.kernel.org
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2014-03-30 19:18:51 -04:00
Al Viro 0b1b901b5a don't bother with propagate_mnt() unless the target is shared
If the dest_mnt is not shared, propagate_mnt() does nothing -
there's no mounts to propagate to and thus no copies to create.
Might as well don't bother calling it in that case.

Cc: stable@vger.kernel.org
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2014-03-30 19:18:50 -04:00
Al Viro 1d6a32acd7 keep shadowed vfsmounts together
preparation to switching mnt_hash to hlist

Cc: stable@vger.kernel.org
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2014-03-30 19:18:50 -04:00
Al Viro 0818bf27c0 resizable namespace.c hashes
* switch allocation to alloc_large_system_hash()
* make sizes overridable by boot parameters (mhash_entries=, mphash_entries=)
* switch mountpoint_hashtable from list_head to hlist_head

Cc: stable@vger.kernel.org
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2014-03-30 19:18:49 -04:00
Sasha Levin d9060742fb ocfs2: check if cluster name exists before deref
Commit c74a3bdd9b ("ocfs2: add clustername to cluster connection") is
trying to strlcpy a string which was explicitly passed as NULL in the
very same patch, triggering a NULL ptr deref.

  BUG: unable to handle kernel NULL pointer dereference at           (null)
  IP: strlcpy (lib/string.c:388 lib/string.c:151)
  CPU: 19 PID: 19426 Comm: trinity-c19 Tainted: G        W     3.14.0-rc7-next-20140325-sasha-00014-g9476368-dirty #274
  RIP:  strlcpy (lib/string.c:388 lib/string.c:151)
  Call Trace:
   ocfs2_cluster_connect (fs/ocfs2/stackglue.c:350)
   ocfs2_cluster_connect_agnostic (fs/ocfs2/stackglue.c:396)
   user_dlm_register (fs/ocfs2/dlmfs/userdlm.c:679)
   dlmfs_mkdir (fs/ocfs2/dlmfs/dlmfs.c:503)
   vfs_mkdir (fs/namei.c:3467)
   SyS_mkdirat (fs/namei.c:3488 fs/namei.c:3472)
   tracesys (arch/x86/kernel/entry_64.S:749)

akpm: this patch probably disables the feature.  A temporary thing to
avoid triviel oopses.

Signed-off-by: Sasha Levin <sasha.levin@oracle.com>
Cc: Goldwyn Rodrigues <rgoldwyn@suse.com>
Cc: Mark Fasheh <mfasheh@suse.de>
Cc: Joel Becker <jlbec@evilplan.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2014-03-28 13:56:58 -07:00
Jan Kara 75c5a52da3 vfs: Allocate anon_inode_inode in anon_inode_init()
Currently we allocated anon_inode_inode in anon_inodefs_mount. This is
somewhat fragile as if that function ever gets called again, it will
overwrite anon_inode_inode pointer. So move the initialization of
anon_inode_inode to anon_inode_init().

Signed-off-by: Jan Kara <jack@suse.cz>
[ Further simplified on suggestion from Dave Jones ]
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2014-03-27 09:52:54 -07:00
Linus Torvalds fce7fc79c8 fs: remove now stale label in anon_inode_init()
The previous commit removed the register_filesystem() call and the
associated error handling, but left the label for the error path that no
longer exists.  Remove that too.

Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2014-03-25 17:43:34 -07:00
Jan Kara d6f2589ad5 fs: Avoid userspace mounting anon_inodefs filesystem
anon_inodefs filesystem is a kernel internal filesystem userspace
shouldn't mess with. Remove registration of it so userspace cannot
even try to mount it (which would fail anyway because the filesystem is
MS_NOUSER).

This fixes an oops triggered by trinity when it tried mounting
anon_inodefs which overwrote anon_inode_inode pointer while other CPU
has been in anon_inode_getfile() between ihold() and d_instantiate().
Thus effectively creating dentry pointing to an inode without holding a
reference to it.

Reported-by: Sasha Levin <sasha.levin@oracle.com>
Signed-off-by: Jan Kara <jack@suse.cz>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2014-03-25 17:42:16 -07:00
Linus Torvalds 632b06aa28 Merge branch 'nfsd-next' of git://linux-nfs.org/~bfields/linux
Pull nfsd fix frm Bruce Fields:
 "J R Okajima sent this early and I was just slow to pass it along,
  apologies.  Fortunately it's a simple fix"

* 'nfsd-next' of git://linux-nfs.org/~bfields/linux:
  nfsd: fix lost nfserrno() call in nfsd_setattr()
2014-03-25 15:24:11 -07:00
Al Viro b37199e626 rcuwalk: recheck mount_lock after mountpoint crossing attempts
We can get false negative from __lookup_mnt() if an unrelated vfsmount
gets moved.  In that case legitimize_mnt() is guaranteed to fail,
and we will fall back to non-RCU walk... unless we end up running
into a hard error on a filesystem object we wouldn't have reached
if not for that false negative.  IOW, delaying that check until
the end of pathname resolution is wrong - we should recheck right
after we attempt to cross the mountpoint.  We don't need to recheck
unless we see d_mountpoint() being true - in that case even if
we have just raced with mount/umount, we can simply go on as if
we'd come at the moment when the sucker wasn't a mountpoint; if we
run into a hard error as the result, it was a legitimate outcome.
__lookup_mnt() returning NULL is different in that respect, since
it might've happened due to operation on completely unrelated
mountpoint.

Cc: stable@vger.kernel.org
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2014-03-23 00:32:55 -04:00
Al Viro e825196d48 make prepend_name() work correctly when called with negative *buflen
In all callchains leading to prepend_name(), the value left in *buflen
is eventually discarded unused if prepend_name() has returned a negative.
So we are free to do what prepend() does, and subtract from *buflen
*before* checking for underflow (which turns into checking the sign
of subtraction result, of course).

Cc: stable@vger.kernel.org
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2014-03-23 00:28:40 -04:00
Eric Biggers 99aea68134 vfs: Don't let __fdget_pos() get FMODE_PATH files
Commit bd2a31d522 ("get rid of fget_light()") introduced the
__fdget_pos() function, which returns the resulting file pointer and
fdput flags combined in an 'unsigned long'.  However, it also changed the
behavior to return files with FMODE_PATH set, which shouldn't happen
because read(), write(), lseek(), etc. aren't allowed on such files.
This commit restores the old behavior.

This regression actually had no effect on read() and write() since
FMODE_READ and FMODE_WRITE are not set on file descriptors opened with
O_PATH, but it did cause lseek() on a file descriptor opened with O_PATH
to fail with ESPIPE rather than EBADF.

Signed-off-by: Eric Biggers <ebiggers3@gmail.com>
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2014-03-23 00:03:12 -04:00
Eric Biggers d7a15f8d07 vfs: atomic f_pos access in llseek()
Commit 9c225f2655 ("vfs: atomic f_pos accesses as per POSIX") changed
several system calls to use fdget_pos() instead of fdget(), but missed
sys_llseek().  Fix it.

Signed-off-by: Eric Biggers <ebiggers3@gmail.com>
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2014-03-23 00:03:12 -04:00
Linus Torvalds 33807f4f0d Merge branch 'for-next' of git://git.samba.org/sfrench/cifs-2.6
Pull CIFS fixes from Steve French:
 "A fix for the problem which Al spotted in cifs_writev and a followup
  (noticed when fixing CVE-2014-0069) patch to ensure that cifs never
  sends more than the smb frame length over the socket (as we saw with
  that cifs_iovec_write problem that Jeff fixed last month)"

* 'for-next' of git://git.samba.org/sfrench/cifs-2.6:
  cifs: mask off top byte in get_rfc1002_length()
  cifs: sanity check length of data to send before sending
  CIFS: Fix wrong pos argument of cifs_find_lock_conflict
2014-03-11 11:53:42 -07:00
Linus Torvalds 8712a00514 Merge branch 'akpm' (patches from Andrew Morton)
Merge misc fixes from Andrew Morton:
 "Nine fixes"

* emailed patches from Andrew Morton akpm@linux-foundation.org>:
  cris: convert ffs from an object-like macro to a function-like macro
  hfsplus: add HFSX subfolder count support
  tools/testing/selftests/ipc/msgque.c: handle msgget failure return correctly
  MAINTAINERS: blackfin: add git repository
  revert "kallsyms: fix absolute addresses for kASLR"
  mm/Kconfig: fix URL for zsmalloc benchmark
  fs/proc/base.c: fix GPF in /proc/$PID/map_files
  mm/compaction: break out of loop on !PageBuddy in isolate_freepages_block
  mm: fix GFP_THISNODE callers and clarify
2014-03-10 17:26:36 -07:00
Sergei Antonov d7d673a591 hfsplus: add HFSX subfolder count support
Adds support for HFSX 'HasFolderCount' flag and a corresponding
'folderCount' field in folder records.  (For reference see
HFS_FOLDERCOUNT and kHFSHasFolderCountBit/kHFSHasFolderCountMask in
Apple's source code.)

Ignoring subfolder count leads to fs errors found by Mac:

  ...
  Checking catalog hierarchy.
  HasFolderCount flag needs to be set (id = 105)
  (It should be 0x10 instead of 0)
  Incorrect folder count in a directory (id = 2)
  (It should be 7 instead of 6)
  ...

Steps to reproduce:
 Format with "newfs_hfs -s /dev/diskXXX".
 Mount in Linux.
 Create a new directory in root.
 Unmount.
 Run "fsck_hfs /dev/diskXXX".

The patch handles directory creation, deletion, and rename.

Signed-off-by: Sergei Antonov <saproj@gmail.com>
Reviewed-by: Vyacheslav Dubeyko <slava@dubeyko.com>
Cc: Al Viro <viro@zeniv.linux.org.uk>
Cc: Christoph Hellwig <hch@infradead.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2014-03-10 17:26:21 -07:00
Artem Fetishev 70335abb26 fs/proc/base.c: fix GPF in /proc/$PID/map_files
The expected logic of proc_map_files_get_link() is either to return 0
and initialize 'path' or return an error and leave 'path' uninitialized.

By the time dname_to_vma_addr() returns 0 the corresponding vma may have
already be gone.  In this case the path is not initialized but the
return value is still 0.  This results in 'general protection fault'
inside d_path().

Steps to reproduce:

  CONFIG_CHECKPOINT_RESTORE=y

    fd = open(...);
    while (1) {
        mmap(fd, ...);
        munmap(fd, ...);
    }

  ls -la /proc/$PID/map_files

Addresses https://bugzilla.kernel.org/show_bug.cgi?id=68991

Signed-off-by: Artem Fetishev <artem_fetishev@epam.com>
Signed-off-by: Aleksandr Terekhov <aleksandr_terekhov@epam.com>
Reported-by: <wiebittewas@gmail.com>
Acked-by: Pavel Emelyanov <xemul@parallels.com>
Acked-by: Cyrill Gorcunov <gorcunov@openvz.org>
Reviewed-by: "Eric W. Biederman" <ebiederm@xmission.com>
Cc: <stable@vger.kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2014-03-10 17:26:20 -07:00
Linus Torvalds e6a4b6f5ea Merge branch 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs
Pull vfs fixes from Al Viro.

Clean up file table accesses (get rid of fget_light() in favor of the
fdget() interface), add proper file position locking.

* 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs:
  get rid of fget_light()
  sockfd_lookup_light(): switch to fdget^W^Waway from fget_light
  vfs: atomic f_pos accesses as per POSIX
  ocfs2 syncs the wrong range...
2014-03-10 12:57:26 -07:00
Al Viro bd2a31d522 get rid of fget_light()
instead of returning the flags by reference, we can just have the
low-level primitive return those in lower bits of unsigned long,
with struct file * derived from the rest.

Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2014-03-10 11:44:42 -04:00
Linus Torvalds 9c225f2655 vfs: atomic f_pos accesses as per POSIX
Our write() system call has always been atomic in the sense that you get
the expected thread-safe contiguous write, but we haven't actually
guaranteed that concurrent writes are serialized wrt f_pos accesses, so
threads (or processes) that share a file descriptor and use "write()"
concurrently would quite likely overwrite each others data.

This violates POSIX.1-2008/SUSv4 Section XSI 2.9.7 that says:

 "2.9.7 Thread Interactions with Regular File Operations

  All of the following functions shall be atomic with respect to each
  other in the effects specified in POSIX.1-2008 when they operate on
  regular files or symbolic links: [...]"

and one of the effects is the file position update.

This unprotected file position behavior is not new behavior, and nobody
has ever cared.  Until now.  Yongzhi Pan reported unexpected behavior to
Michael Kerrisk that was due to this.

This resolves the issue with a f_pos-specific lock that is taken by
read/write/lseek on file descriptors that may be shared across threads
or processes.

Reported-by: Yongzhi Pan <panyongzhi@gmail.com>
Reported-by: Michael Kerrisk <mtk.manpages@gmail.com>
Cc: Al Viro <viro@zeniv.linux.org.uk>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2014-03-10 11:44:41 -04:00
Al Viro 1b56e98990 ocfs2 syncs the wrong range...
Cc: stable@vger.kernel.org
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2014-03-10 11:43:32 -04:00