| Age | Commit message (Collapse) | Author |
|---|
|
search_binary_handler() uses "for (try=0; try<2; try++)" to avoid "goto"
but the code looks too complicated and horrible imho. We still need to
check "try == 0" before request_module() and add the additional "break"
for !CONFIG_MODULES case.
Kill this loop and use a simple "bool need_retry" + "goto retry". The
code looks much simpler and we do not even need ifdef's, gcc can optimize
out the "if (need_retry)" block if !IS_ENABLED().
Signed-off-by: Oleg Nesterov <oleg@redhat.com>
Acked-by: Kees Cook <keescook@chromium.org>
Cc: Al Viro <viro@ZenIV.linux.org.uk>
Cc: Evgeniy Polyakov <zbr@ioremap.net>
Cc: Zach Levis <zml@linux.vnet.ibm.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
|
|
search_binary_handler() checks ->load_binary != NULL for no reason, this
method should be always defined. Turn this check into WARN_ON() and move
it into __register_binfmt().
Also, kill the function pointer. The current code looks confusing, as if
->load_binary can go away after read_unlock(&binfmt_lock). But we rely on
module_get(fmt->module), this fmt can't be changed or unregistered,
otherwise this code is buggy anyway.
Signed-off-by: Oleg Nesterov <oleg@redhat.com>
Acked-by: Kees Cook <keescook@chromium.org>
Cc: Al Viro <viro@ZenIV.linux.org.uk>
Cc: Evgeniy Polyakov <zbr@ioremap.net>
Cc: Zach Levis <zml@linux.vnet.ibm.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
|
|
When search_binary_handler() succeeds it does allow_write_access() and
fput(), then it clears bprm->file to ensure the caller will not do the
same.
We can simply move this code to exec_binprm() which is called only once.
In fact we could move this to free_bprm() and remove the same code in
do_execve_common's error path.
Signed-off-by: Oleg Nesterov <oleg@redhat.com>
Acked-by: Kees Cook <keescook@chromium.org>
Cc: Al Viro <viro@ZenIV.linux.org.uk>
Cc: Evgeniy Polyakov <zbr@ioremap.net>
Cc: Zach Levis <zml@linux.vnet.ibm.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
|
|
A separate one-liner with the minor fix.
PROC_EVENT_EXEC reports the "exec" event, but this message is sent at
least twice if search_binary_handler() is called by ->load_binary()
recursively, say, load_script().
Move it to exec_binprm(), this is "depth == 0" code too.
Signed-off-by: Oleg Nesterov <oleg@redhat.com>
Acked-by: Kees Cook <keescook@chromium.org>
Cc: Al Viro <viro@ZenIV.linux.org.uk>
Cc: Evgeniy Polyakov <zbr@ioremap.net>
Cc: Zach Levis <zml@linux.vnet.ibm.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
|
|
Nobody except search_binary_handler() should touch ->recursion_depth, "int
depth" buys nothing but complicates the code, kill it.
Probably we should also kill "fn" and the !NULL check, ->load_binary
should be always defined. And it can not go away after read_unlock() or
this code is buggy anyway.
Signed-off-by: Oleg Nesterov <oleg@redhat.com>
Acked-by: Kees Cook <keescook@chromium.org>
Cc: Al Viro <viro@ZenIV.linux.org.uk>
Cc: Evgeniy Polyakov <zbr@ioremap.net>
Cc: Zach Levis <zml@linux.vnet.ibm.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
|
|
task_pid_nr_ns() and trace/ptrace code in the middle of the recursive
search_binary_handler() looks confusing and imho annoying. We only need
this code if "depth == 0", lets add a simple helper which calls
search_binary_handler() and does trace_sched_process_exec() +
ptrace_event().
The patch also moves the setting of task->did_exec, we need to do this
only once.
Note: we can kill either task->did_exec or PF_FORKNOEXEC.
Signed-off-by: Oleg Nesterov <oleg@redhat.com>
Acked-by: Kees Cook <keescook@chromium.org>
Cc: Al Viro <viro@ZenIV.linux.org.uk>
Cc: Evgeniy Polyakov <zbr@ioremap.net>
Cc: Zach Levis <zml@linux.vnet.ibm.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
|
|
dir_emit_dots() is called twice. Looks like a typo.
Signed-off-by: Andrey Vagin <avagin@openvz.org>
Cc: Al Viro <viro@zeniv.linux.org.uk>
Cc: Cyrill Gorcunov <gorcunov@openvz.org>
Cc: Pavel Emelyanov <xemul@parallels.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
|
|
make fput() comment more truthful
Cc: "Eric W. Biederman" <ebiederm@xmission.com>
Cc: Andrey Vagin <avagin@openvz.org>
Cc: Oleg Nesterov <oleg@redhat.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
|
|
task_struct->saved_sigmask has no meaning unless we return with
set_restore_sigmask() and nobody except current can use it.
This means that sys_epoll_pwait() doesn't need to save ->blocked
into the local var and then memcopy it into ->saved_sigmask, we
can simply set ->saved_sigmask right before set_current_blocked().
Signed-off-by: Oleg Nesterov <oleg@redhat.com>
Cc: Al Viro <viro@zeniv.linux.org.uk>
Cc: Denys Vlasenko <dvlasenk@redhat.com>
Cc: Eric Wong <normalperson@yhbt.net>
Cc: Jason Baron <jbaron@redhat.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
|
|
fix min() warning
Cc: Amit Sahrawat <a.sahrawat@samsung.com>
Cc: Namjae Jeon <namjae.jeon@samsung.com>
Cc: OGAWA Hirofumi <hirofumi@mail.parknet.co.jp>
Cc: Ravishankar N <ravi.n1@samsung.com>
Reported-by: Wu Fengguang <fengguang.wu@intel.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
|
|
Implement preallocation via the fallocate syscall on VFAT partitions.
With FALLOC_FL_KEEP_SIZE, there is no way to distinguish if the mismatch
between i_size and no. of clusters allocated is a consequence of
fallocate or just plain corruption. When a non fallocate aware (old)
linux fat driver tries to write to such a file, it throws an error.Also,
fsck detects this as inconsistency and truncates the prealloc'd blocks.
To avoid this, as suggested by OGAWA, remove changes that make fallocate
persistent across mounts and restrict lifetime of blocks from fallocate(2)
to file release.
Signed-off-by: Namjae Jeon <namjae.jeon@samsung.com>
Signed-off-by: Ravishankar N <ravi.n1@samsung.com>
Signed-off-by: Amit Sahrawat <a.sahrawat@samsung.com>
Cc: OGAWA Hirofumi <hirofumi@mail.parknet.co.jp>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
|
|
Integrate implemented POSIX ACLs support into hfsplus driver.
Signed-off-by: Vyacheslav Dubeyko <slava@dubeyko.com>
Cc: Al Viro <viro@zeniv.linux.org.uk>
Cc: Christoph Hellwig <hch@infradead.org>
Cc: Hin-Tak Leung <htl10@users.sourceforge.net>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
|
|
Implement POSIX ACLs support in hfsplus driver.
Signed-off-by: Vyacheslav Dubeyko <slava@dubeyko.com>
Cc: Al Viro <viro@zeniv.linux.org.uk>
Cc: Christoph Hellwig <hch@infradead.org>
Cc: Hin-Tak Leung <htl10@users.sourceforge.net>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
|
|
This patchset implements POSIX ACLs support in hfsplus driver.
Mac OS X beginning with version 10.4 ("Tiger") support NFSv4 ACLs, which
are part of the NFSv4 standard. HFS+ stores ACLs in the form of specially
named extended attributes (com.apple.system.Security).
But this patchset doesn't use "com.apple.system.Security" extended
attributes. It implements support of POSIX ACLs in the form of extended
attributes with names "system.posix_acl_access" and
"system.posix_acl_default". These xattrs are treated only under Linux.
POSIX ACLs doesn't mean something under Mac OS X. Thereby, this patch set
provides opportunity to use POSIX ACLs under Linux on HFS+ filesystem.
This patch:
Add CONFIG_HFSPLUS_FS_POSIX_ACL kernel configuration option, DBG_ACL_MOD
debugging flag and acl.h file with declaration of essential functions for
support POSIX ACLs in hfsplus driver.
Signed-off-by: Vyacheslav Dubeyko <slava@dubeyko.com>
Cc: Al Viro <viro@zeniv.linux.org.uk>
Cc: Christoph Hellwig <hch@infradead.org>
Cc: Hin-Tak Leung <htl10@users.sourceforge.net>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
|
|
The PID and the TGID of the process triggering the mount are sent to the
daemon. Currently the global pid values are sent (ones valid in the
initial pid namespace) but this is wrong if the autofs daemon itself is
not running in the initial pid namespace.
So send the pid values that are valid in the namespace of the autofs daemon.
The namespace to use is taken from the oz_pgrp pid pointer, which was set
at mount time to the mounting process' pid namespace.
If the pid translation fails (the triggering process is in an unrelated
pid namespace) then the automount fails with ENOENT.
Signed-off-by: Miklos Szeredi <mszeredi@suse.cz>
Acked-by: Serge Hallyn <serge.hallyn@canonical.com>
Cc: Eric Biederman <ebiederm@xmission.com>
Cc: Ian Kent <raven@themaw.net>
Cc: Oleg Nesterov <oleg@redhat.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
|
|
Enable autofs4 to work in a "container". oz_pgrp is converted from pid_t
to struct pid and this is stored at mount time based on the "pgrp=" option
or if the option is missing then the current pgrp.
The "pgrp=" option is interpreted in the PID namespace of the current
process. This option is flawed in that it doesn't carry the namespace
information, so it should be deprecated. AFAICS the autofs daemon always
sends the current pgrp, which is the default anyway.
The oz_pgrp is also set from the AUTOFS_DEV_IOCTL_SETPIPEFD_CMD ioctl.
This ioctl sets oz_pgrp to the current pgrp. It is not allowed to change
the pid namespace.
oz_pgrp is used mainly to determine whether the process traversing the
autofs mount tree is the autofs daemon itself or not. This function now
compares the pid pointers instead of the pid_t values.
One other use of oz_pgrp is in autofs4_show_options. There is shows the
virtual pid number (i.e. the one that is valid inside the PID namespace
of the calling process)
For debugging printk convert oz_pgrp to the value in the initial pid
namespace.
Signed-off-by: Sukadev Bhattiprolu <sukadev@us.ibm.com>
Signed-off-by: Miklos Szeredi <mszeredi@suse.cz>
Acked-by: Serge Hallyn <serge.hallyn@canonical.com>
Cc: Eric Biederman <ebiederm@xmission.com>
Cc: Ian Kent <raven@themaw.net>
Cc: Oleg Nesterov <oleg@redhat.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
|
|
Entropy is quickly depleted under normal operations like ls(1), cat(1),
etc... between 2.6.30 to current mainline, for instance:
$ cat /proc/sys/kernel/random/entropy_avail
3428
$ cat /proc/sys/kernel/random/entropy_avail
2911
$cat /proc/sys/kernel/random/entropy_avail
2620
We observed this problem has been occurring since 2.6.30 with
fs/binfmt_elf.c: create_elf_tables()->get_random_bytes(), introduced by
f06295b44c296c8f ("ELF: implement AT_RANDOM for glibc PRNG seeding").
/*
* Generate 16 random bytes for userspace PRNG seeding.
*/
get_random_bytes(k_rand_bytes, sizeof(k_rand_bytes));
The patch introduces a wrapper around get_random_int() which has lower
overhead than calling get_random_bytes() directly.
With this patch applied:
$ cat /proc/sys/kernel/random/entropy_avail
2731
$ cat /proc/sys/kernel/random/entropy_avail
2802
$ cat /proc/sys/kernel/random/entropy_avail
2878
Analyzed by John Sobecki.
Signed-off-by: Jie Liu <jeff.liu@oracle.com>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Al Viro <viro@zeniv.linux.org.uk>
Cc: Andreas Dilger <aedilger@gmail.com>
Cc: Alan Cox <alan@linux.intel.com>
Cc: Arnd Bergmann <arnn@arndb.de>
Cc: John Sobecki <john.sobecki@oracle.com>
Cc: James Morris <james.l.morris@oracle.com>
Cc: Jakub Jelinek <jakub@redhat.com>
Cc: Ted Ts'o <tytso@mit.edu>
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Acked-by: Kees Cook <keescook@chromium.org>
Cc: Ulrich Drepper <drepper@redhat.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
|
|
We use NR_ANON_PAGES as base for reporting AnonPages to user. There's not
much sense in not accounting transparent huge pages there, but add them on
printing to user.
Let's account transparent huge pages in NR_ANON_PAGES in the first place.
Signed-off-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
Acked-by: Dave Hansen <dave.hansen@linux.intel.com>
Cc: Andrea Arcangeli <aarcange@redhat.com>
Cc: Al Viro <viro@zeniv.linux.org.uk>
Cc: Hugh Dickins <hughd@google.com>
Cc: Wu Fengguang <fengguang.wu@intel.com>
Cc: Jan Kara <jack@suse.cz>
Cc: Mel Gorman <mgorman@suse.de>
Cc: Andi Kleen <ak@linux.intel.com>
Cc: Matthew Wilcox <willy@linux.intel.com>
Cc: Hillf Danton <dhillf@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
|
|
The ocfs2 path is not properly freed which leads to a memory leak at
__ocfs2_move_extents().
This patch stops the leaks of the ocfs2_path structure.
Signed-off-by: Jie Liu <jeff.liu@oracle.com>
Reviewed-by: Younger Liu <younger.liu@huawei.com>
Cc: Joel Becker <jlbec@evilplan.org>
Cc: Mark Fasheh <mfasheh@suse.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
|
|
In ocfs2_attach_refcount_tree() and ocfs2_duplicate_extent_list(), if
error occurs when calling ocfs2_get_clusters(), it will go with
unexpected behavior as local variables p_cluster, num_clusters and
ext_flags are declared without initialization.
Signed-off-by: Joseph Qi <joseph.qi@huawei.com>
Reviewed-by: Jie Liu <jeff.liu@oracle.com>
Cc: Joel Becker <jlbec@evilplan.org>
Cc: Mark Fasheh <mfasheh@suse.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
|
|
In ocfs2_acl_from_xattr(), if size is less than sizeof(struct
posix_acl_entry), it returns ERR_PTR(-EINVAL) directly. Then assign (size
/ sizeof(struct posix_acl_entry)) to count which will be at least 1, that
means the following branch (count < 0) and (count == 0) will never be
true.
Signed-off-by: Joseph Qi <joseph.qi@huawei.com>
Cc: Mark Fasheh <mfasheh@suse.com>
Cc: Joel Becker <jlbec@evilplan.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
|
|
Signed-off-by: Dong Fang <yp.fangdong@gmail.com>
Cc: Dan Carpenter <dan.carpenter@oracle.com>
Cc: Mark Fasheh <mfasheh@suse.com>
Cc: Joel Becker <jlbec@evilplan.org>
Cc: Jeff Liu <jeff.liu@oracle.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
|
|
Fix some possible null pointer dereferences that were detected by the
static code analyser, smatch.
Signed-off-by: Sunil Mushran <sunil.mushran@oracle.com>
Reported-by: Dan Carpenter <error27@gmail.com>
Reported-by: Guozhonghua <guozhonghua@h3c.com>
Cc: Sunil Mushran <sunil.mushran@gmail.com>
Cc: Joseph Qi <joseph.qi@huawei.com>
Cc: Mark Fasheh <mfasheh@suse.com>
Cc: Joel Becker <jlbec@evilplan.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
|
|
There is an issue in reserving and claiming space for localalloc, When
localalloc space is not enough, it would claim space from global_bitmap.
And if there is not enough free space in global_bitmap, the size of
claiming space would set to half of orignal size and retry.
The issue is as follows: osb->local_alloc_bits is set to half of orignal
size in ocfs2_recalc_la_window(), but ac->ac_bits_wanted is set to
osb->local_alloc_default_bits which is not changed. localalloc always
reserves and claims local_alloc_default_bits space and returns ENOSPC.
So, ac->ac_bits_wanted should be osb->local_alloc_bits which would be
changed.
Signed-off-by: Younger Liu <younger.liu@huawei.com>
Cc: Joel Becker <jlbec@evilplan.org>
Cc: Mark Fasheh <mfasheh@suse.com>
Cc: Jeff Liu <jeff.liu@oracle.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
|
|
dlm_request_all_locks() should deal with the status sent from target node
if DLM_LOCK_REQUEST_MSG is sent successfully, or recovery master will fall
into endless loop, waiting for other nodes to send locks and
DLM_RECO_DATA_DONE_MSG to me.
NodeA NodeB
selected as recovery master
dlm_remaster_locks()
->dlm_request_all_locks()
send DLM_LOCK_REQUEST_MSG to nodeA
It happened that NodeA cannot alloc memory when it processes this message.
dlm_request_all_locks_handler() do not queue dlm_request_all_locks_worker
and returns -ENOMEM. It will never send locks andDLM_RECO_DATA_DONE_MSG
to NodeB.
NodeB do not deal with the status
sent from nodeA, and will fall in
endless loop waiting for the
recovery state of NodeA to be
changed.
Signed-off-by: joyce <xuejiufei@huawei.com>
Cc: Mark Fasheh <mfasheh@suse.com>
Cc: Jeff Liu <jeff.liu@oracle.com>
Cc: Joel Becker <jlbec@evilplan.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
|
|
Though ocfs2 uses inode->i_mutex to protect i_size, there are both
i_size_read/write() and direct accesses. Clean up all direct access to
eliminate confusion.
Signed-off-by: Junxiao Bi <junxiao.bi@oracle.com>
Cc: Jie Liu <jeff.liu@oracle.com>
Cc: Mark Fasheh <mfasheh@suse.com>
Cc: Joel Becker <jlbec@evilplan.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
|
|
The issue scenario is as following:
When fallocating a very large disk space for a small file,
__ocfs2_extend_allocation attempts to get a very large transaction. For
some journal sizes, there may be not enough room for this transaction, and
the fallocate will fail.
The patch below extends & restarts the transaction as necessary while
allocating space, and should work with even the smallest journal. This
patch refers ext4 resize.
Test:
# mkfs.ocfs2 -b 4K -C 32K -T datafiles /dev/sdc
...(jounral size is 32M)
# mount.ocfs2 /dev/sdc /mnt/ocfs2/
# touch /mnt/ocfs2/1.log
# fallocate -o 0 -l 400G /mnt/ocfs2/1.log
fallocate: /mnt/ocfs2/1.log: fallocate failed: Cannot allocate memory
# tail -f /var/log/messages
[ 7372.278591] JBD: fallocate wants too many credits (2051 > 2048)
[ 7372.278597] (fallocate,6438,0):__ocfs2_extend_allocation:709 ERROR: status = -12
[ 7372.278603] (fallocate,6438,0):ocfs2_allocate_unwritten_extents:1504 ERROR: status = -12
[ 7372.278607] (fallocate,6438,0):__ocfs2_change_file_space:1955 ERROR: status = -12
^C
With this patch, the test works well.
Signed-off-by: Younger Liu <younger.liu@huawei.com>
Cc: Jie Liu <jeff.liu@oracle.com>
Cc: Joel Becker <jlbec@evilplan.org>
Cc: Mark Fasheh <mfasheh@suse.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
|
|
fs-writeback will release the dirty pages without page lock whose offset
are over inode size, the release happens at block_write_full_page_endio().
If not update, dirty pages in file holes may be released before flushed
to the disk, then file holes will contain some non-zero data, this will
cause sparse file md5sum error.
To reproduce the bug, find a big sparse file with many holes, like vm
image file, its actual size should be bigger than available mem size to
make writeback work more frequently, tar it with -S option, then keep
untar it and check its md5sum again and again until you get a wrong
md5sum.
Signed-off-by: Junxiao Bi <junxiao.bi@oracle.com>
Cc: Younger Liu <younger.liu@huawei.com>
Cc: Mark Fasheh <mfasheh@suse.com>
Cc: Joel Becker <jlbec@evilplan.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
|
|
Compared with PATCH V1, bug description is updated, and pointless comments
are removed.
Signed-off-by: Younger Liu <younger.liu@huawei.com>
Cc: Jie Liu <jeff.liu@oracle.com>
Cc: Joel Becker <jlbec@evilplan.org>
Cc: Mark Fasheh <mfasheh@suse.com>
Cc: Sunil Mushran <sunil.mushran@gmail.com>
Cc: Jensen <shencanquan@huawei.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
|
|
The issue scenario is as following:
- Create a small file and fallocate a large disk space for a file with
FALLOC_FL_KEEP_SIZE option.
- ftruncate the file back to the original size again. but the disk free
space is not changed back. This is a real bug that be fixed in this
patch.
In order to solve the issue above, we modified ocfs2_setattr(), if
attr->ia_size != i_size_read(inode), It calls ocfs2_truncate_file(), and
truncate disk space to attr->ia_size.
Signed-off-by: Younger Liu <younger.liu@huawei.com>
Reviewed-by: Jie Liu <jeff.liu@oracle.com>
Tested-by: Jie Liu <jeff.liu@oracle.com>
Cc: Joel Becker <jlbec@evilplan.org>
Cc: Mark Fasheh <mfasheh@suse.com>
Cc: Sunil Mushran <sunil.mushran@gmail.com>
Reviewed-by: Jensen <shencanquan@huawei.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
|
|
llseek requires ocfs2 inode lock for updating the file size in SEEK_END.
because the file size maybe update on another node.
This bug can be reproduce the following scenario: at first, we dd a test
fileA, the file size is 10k.
on NodeA:
---------
1) open the test fileA, lseek the end of file. and print the position.
2) close the test fileA
on NodeB:
1) open the test fileA, append the 5k data to test FileA.
2) lseek the end of file. and print the position.
3) close file.
At first we run the test program1 on NodeA , the result is 10k. And then
run the test program2 on NodeB, the result is 15k. At last, we run the
test program1 on NodeA again, the result is 10k.
After applying this patch the three step result is 15k.
Signed-off-by: Jensen <shencanquan@huawei.com>
Cc: Jie Liu <jeff.liu@oracle.com>
Acked-by: Joel Becker <jlbec@evilplan.org>
Cc: Mark Fasheh <mfasheh@suse.com>
Cc: Sunil Mushran <sunil.mushran@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
|
|
ocfs2_orphan_del()
While deleting a file into orphan dir in ocfs2_orphan_del(), it calls
ocfs2_delete_entry() before ocfs2_journal_access_di(). If
ocfs2_delete_entry() succeeded and ocfs2_journal_access_di() failed, there
would be a inconsistency: the file is deleted from orphan dir, but orphan
dir dinode is not updated.
So we need to call ocfs2_journal_access_di() before ocfs2_orphan_del().
Signed-off-by: Younger Liu <younger.liu@huawei.com>
Reviewed-by: Jensen <shencanquan@huawei.com>
Cc: Jie Liu <jeff.liu@oracle.com>
Cc: Joel Becker <jlbec@evilplan.org>
Cc: Mark Fasheh <mfasheh@suse.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
|
|
Fix a NULL pointer deference while removing an empty directory, which was
introduced by 3704412bdbf3 ("[readdir] convert ocfs2").
BUG: unable to handle kernel NULL pointer dereference at (null)
IP: [< (null)>] (null)
PGD 6da85067 PUD 6da89067 PMD 0
Oops: 0010 [#1] SMP
CPU: 0 PID: 6564 Comm: rmdir Tainted: G O 3.11.0-rc1 #4
RIP: 0010:[<0000000000000000>] [< (null)>] (null)
Call Trace:
[<ffffffffa038a30e>] ? ocfs2_dir_foreach_blk_id+0x17e/0x220 [ocfs2]
[<ffffffffa038e5f9>] ocfs2_dir_foreach+0x49/0x50 [ocfs2]
[<ffffffffa038ec2c>] ocfs2_empty_dir+0x12c/0x3e0 [ocfs2]
[<ffffffffa03b3ade>] ocfs2_unlink+0x56e/0xc10 [ocfs2]
[<ffffffff811b3a05>] vfs_rmdir+0xd5/0x140
[<ffffffff811b3c3b>] do_rmdir+0x1cb/0x1e0
[<ffffffff813697f4>] ? lockdep_sys_exit_thunk+0x35/0x67
[<ffffffff8136977e>] ? trace_hardirqs_on_thunk+0x3a/0x3f
[<ffffffff811b6996>] SyS_rmdir+0x16/0x20
[<ffffffff816e2a82>] system_call_fastpath+0x16/0x1b
Code: Bad RIP value.
RIP [< (null)>] (null)
RSP <ffff88006daddc10>
CR2: 0000000000000000
Signed-off-by: Jie Liu <jeff.liu@oracle.com>
Reported-by: David Weber <wb@munzinger.de>
Cc: Al Viro <viro@zeniv.linux.org.uk>
Cc: Joel Becker <jlbec@evilplan.org>
Cc: Mark Fasheh <mfasheh@suse.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
|
|
Andy reported that if file page get reclaimed we lose the soft-dirty bit
if it was there, so save _PAGE_BIT_SOFT_DIRTY bit when page address get
encoded into pte entry. Thus when #pf happens on such non-present pte we
can restore it back.
Reported-by: Andy Lutomirski <luto@amacapital.net>
Signed-off-by: Cyrill Gorcunov <gorcunov@openvz.org>
Acked-by: Pavel Emelyanov <xemul@parallels.com>
Cc: Matt Mackall <mpm@selenic.com>
Cc: Xiao Guangrong <xiaoguangrong@linux.vnet.ibm.com>
Cc: Marcelo Tosatti <mtosatti@redhat.com>
Cc: KOSAKI Motohiro <kosaki.motohiro@gmail.com>
Cc: Stephen Rothwell <sfr@canb.auug.org.au>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: "Aneesh Kumar K.V" <aneesh.kumar@linux.vnet.ibm.com>
Cc: Minchan Kim <minchan@kernel.org>
Cc: Wanpeng Li <liwanp@linux.vnet.ibm.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
|
|
Andy Lutomirski reported that if a page with _PAGE_SOFT_DIRTY bit set get
swapped out, the bit is getting lost and no longer available when pte read
back.
To resolve this we introduce _PTE_SWP_SOFT_DIRTY bit which is saved in pte
entry for the page being swapped out. When such page is to be read back
from a swap cache we check for bit presence and if it's there we clear it
and restore the former _PAGE_SOFT_DIRTY bit back.
One of the problem was to find a place in pte entry where we can save the
_PTE_SWP_SOFT_DIRTY bit while page is in swap. The _PAGE_PSE was chosen
for that, it doesn't intersect with swap entry format stored in pte.
Reported-by: Andy Lutomirski <luto@amacapital.net>
Signed-off-by: Cyrill Gorcunov <gorcunov@openvz.org>
Acked-by: Pavel Emelyanov <xemul@parallels.com>
Cc: Matt Mackall <mpm@selenic.com>
Cc: Xiao Guangrong <xiaoguangrong@linux.vnet.ibm.com>
Cc: Marcelo Tosatti <mtosatti@redhat.com>
Cc: KOSAKI Motohiro <kosaki.motohiro@gmail.com>
Cc: Stephen Rothwell <sfr@canb.auug.org.au>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: "Aneesh Kumar K.V" <aneesh.kumar@linux.vnet.ibm.com>
Reviewed-by: Minchan Kim <minchan@kernel.org>
Reviewed-by: Wanpeng Li <liwanp@linux.vnet.ibm.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
|
|
find_or_create_page()
Add the missing NULL check of the return value of find_or_create_page() in
function ocfs2_duplicate_clusters_by_page().
[akpm@linux-foundation.org: fix layout, per Joel]
Signed-off-by: Gu Zheng <guz.fnst@cn.fujitsu.com>
Acked-by: Joel Becker <jlbec@evilplan.org>
Cc: Mark Fasheh <mfasheh@suse.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
|
|
Pull xfs fix from Ben Myers:
"Fix for regression in commit cca9f93a52d2 ("xfs: don't do IO when
creating an new inode"), recovery causing filesystem corruption after
a crash"
* tag 'for-linus-v3.11-rc3' of git://oss.sgi.com/xfs/xfs:
xfs: di_flushiter considered harmful
|
|
Pull nfsd fix from Bruce Fields:
"One more nfsd bugfix for 3.11"
* 'for-3.11' of git://linux-nfs.org/~bfields/linux:
nfsd: nfsd_open: when dentry_open returns an error do not propagate as struct file
|
|
When we made all inode updates transactional, we no longer needed
the log recovery detection for inodes being newer on disk than the
transaction being replayed - it was redundant as replay of the log
would always result in the latest version of the inode would be on
disk. It was redundant, but left in place because it wasn't
considered to be a problem.
However, with the new "don't read inodes on create" optimisation,
flushiter has come back to bite us. Essentially, the optimisation
made always initialises flushiter to zero in the create transaction,
and so if we then crash and run recovery and the inode already on
disk has a non-zero flushiter it will skip recovery of that inode.
As a result, log recovery does the wrong thing and we end up with a
corrupt filesystem.
Because we have to support old kernel to new kernel upgrades, we
can't just get rid of the flushiter support in log recovery as we
might be upgrading from a kernel that doesn't have fully transactional
inode updates. Unfortunately, for v4 superblocks there is no way to
guarantee that log recovery knows about this fact.
We cannot add a new inode format flag to say it's a "special inode
create" because it won't be understood by older kernels and so
recovery could do the wrong thing on downgrade. We cannot specially
detect the combination of zero mode/non-zero flushiter on disk to
non-zero mode, zero flushiter in the log item during recovery
because wrapping of the flushiter can result in false detection.
Hence that makes this "don't use flushiter" optimisation limited to
a disk format that guarantees that we don't need it. And that means
the only fix here is to limit the "no read IO on create"
optimisation to version 5 superblocks....
Reported-by: Markus Trippelsdorf <markus@trippelsdorf.de>
Signed-off-by: Dave Chinner <dchinner@redhat.com>
Reviewed-by: Mark Tinguely <tinguely@sgi.com>
Signed-off-by: Ben Myers <bpm@sgi.com>
(cherry picked from commit e60896d8f2b81412421953e14d3feb14177edb56)
|
|
git://git.kernel.org/pub/scm/linux/kernel/git/mszeredi/fuse
Pull fuse bugfixes from Miklos Szeredi:
"These are bugfixes and a cleanup to the "readdirplus" feature"
* 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/mszeredi/fuse:
fuse: readdirplus: cleanup
fuse: readdirplus: change attributes once
fuse: readdirplus: fix instantiate
fuse: readdirplus: sanity checks
fuse: readdirplus: fix dentry leak
|
|
The calculation of the attribute length was 4 bytes off.
Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>
Tested-by: Andre Heider <a.heider@gmail.com>
Reported-and-tested-by: Henrik Rydberg <rydberg@euromail.se>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
|
|
struct file
The following call chain:
------------------------------------------------------------
nfs4_get_vfs_file
- nfsd_open
- dentry_open
- do_dentry_open
- __get_file_write_access
- get_write_access
- return atomic_inc_unless_negative(&inode->i_writecount) ? 0 : -ETXTBSY;
------------------------------------------------------------
can result in the following state:
------------------------------------------------------------
struct nfs4_file {
...
fi_fds = {0xffff880c1fa65c80, 0xffffffffffffffe6, 0x0},
fi_access = {{
counter = 0x1
}, {
counter = 0x0
}},
...
------------------------------------------------------------
1) First time around, in nfs4_get_vfs_file() fp->fi_fds[O_WRONLY] is
NULL, hence nfsd_open() is called where we get status set to an error
and fp->fi_fds[O_WRONLY] to -ETXTBSY. Thus we do not reach
nfs4_file_get_access() and fi_access[O_WRONLY] is not incremented.
2) Second time around, in nfs4_get_vfs_file() fp->fi_fds[O_WRONLY] is
NOT NULL (-ETXTBSY), so nfsd_open() is NOT called, but
nfs4_file_get_access() IS called and fi_access[O_WRONLY] is incremented.
Thus we leave a landmine in the form of the nfs4_file data structure in
an incorrect state.
3) Eventually, when __nfs4_file_put_access() is called it finds
fi_access[O_WRONLY] being non-zero, it decrements it and calls
nfs4_file_put_fd() which tries to fput -ETXTBSY.
------------------------------------------------------------
...
[exception RIP: fput+0x9]
RIP: ffffffff81177fa9 RSP: ffff88062e365c90 RFLAGS: 00010282
RAX: ffff880c2b3d99cc RBX: ffff880c2b3d9978 RCX: 0000000000000002
RDX: dead000000100101 RSI: 0000000000000001 RDI: ffffffffffffffe6
RBP: ffff88062e365c90 R8: ffff88041fe797d8 R9: ffff88062e365d58
R10: 0000000000000008 R11: 0000000000000000 R12: 0000000000000001
R13: 0000000000000007 R14: 0000000000000000 R15: 0000000000000000
ORIG_RAX: ffffffffffffffff CS: 0010 SS: 0018
#9 [ffff88062e365c98] __nfs4_file_put_access at ffffffffa0562334 [nfsd]
#10 [ffff88062e365cc8] nfs4_file_put_access at ffffffffa05623ab [nfsd]
#11 [ffff88062e365ce8] free_generic_stateid at ffffffffa056634d [nfsd]
#12 [ffff88062e365d18] release_open_stateid at ffffffffa0566e4b [nfsd]
#13 [ffff88062e365d38] nfsd4_close at ffffffffa0567401 [nfsd]
#14 [ffff88062e365d88] nfsd4_proc_compound at ffffffffa0557f28 [nfsd]
#15 [ffff88062e365dd8] nfsd_dispatch at ffffffffa054543e [nfsd]
#16 [ffff88062e365e18] svc_process_common at ffffffffa04ba5a4 [sunrpc]
#17 [ffff88062e365e98] svc_process at ffffffffa04babe0 [sunrpc]
#18 [ffff88062e365eb8] nfsd at ffffffffa0545b62 [nfsd]
#19 [ffff88062e365ee8] kthread at ffffffff81090886
#20 [ffff88062e365f48] kernel_thread at ffffffff8100c14a
------------------------------------------------------------
Cc: stable@vger.kernel.org
Signed-off-by: Harshula Jayasuriya <harshula@redhat.com>
Signed-off-by: J. Bruce Fields <bfields@redhat.com>
|
|
When we try to open a file with O_TMPFILE flag, we will trigger a bug.
The root cause is that in ext4_orphan_add() we check ->i_nlink == 0 and
this check always fails because we set ->i_nlink = 1 in
inode_init_always(). We can use the following program to trigger it:
int main(int argc, char *argv[])
{
int fd;
fd = open(argv[1], O_TMPFILE, 0666);
if (fd < 0) {
perror("open ");
return -1;
}
close(fd);
return 0;
}
The oops message looks like this:
kernel: kernel BUG at fs/ext3/namei.c:1992!
kernel: invalid opcode: 0000 [#1] SMP
kernel: Modules linked in: ext4 jbd2 crc16 cpufreq_ondemand ipv6 dm_mirror dm_region_hash dm_log dm_mod parport_pc parport serio_raw sg dcdbas pcspkr i2c_i801 ehci_pci ehci_hcd button acpi_cpufreq mperf e1000e ptp pps_core ttm drm_kms_helper drm hwmon i2c_algo_bit i2c_core ext3 jbd sd_mod ahci libahci libata scsi_mod uhci_hcd
kernel: CPU: 0 PID: 2882 Comm: tst_tmpfile Not tainted 3.11.0-rc1+ #4
kernel: Hardware name: Dell Inc. OptiPlex 780 /0V4W66, BIOS A05 08/11/2010
kernel: task: ffff880112d30050 ti: ffff8801124d4000 task.ti: ffff8801124d4000
kernel: RIP: 0010:[<ffffffffa00db5ae>] [<ffffffffa00db5ae>] ext3_orphan_add+0x6a/0x1eb [ext3]
kernel: RSP: 0018:ffff8801124d5cc8 EFLAGS: 00010202
kernel: RAX: 0000000000000000 RBX: ffff880111510128 RCX: ffff8801114683a0
kernel: RDX: 0000000000000000 RSI: ffff880111510128 RDI: ffff88010fcf65a8
kernel: RBP: ffff8801124d5d18 R08: 0080000000000000 R09: ffffffffa00d3b7f
kernel: R10: ffff8801114683a0 R11: ffff8801032a2558 R12: 0000000000000000
kernel: R13: ffff88010fcf6800 R14: ffff8801032a2558 R15: ffff8801115100d8
kernel: FS: 00007f5d172b5700(0000) GS:ffff880117c00000(0000) knlGS:0000000000000000
kernel: CS: 0010 DS: 0000 ES: 0000 CR0: 000000008005003b
kernel: CR2: 00007f5d16df15d0 CR3: 0000000110b1d000 CR4: 00000000000407f0
kernel: Stack:
kernel: 000000000000000c ffff8801048a7dc8 ffff8801114685a8 ffffffffa00b80d7
kernel: ffff8801124d5e38 ffff8801032a2558 ffff88010ce24d68 0000000000000000
kernel: ffff88011146b300 ffff8801124d5d44 ffff8801124d5d78 ffffffffa00db7e1
kernel: Call Trace:
kernel: [<ffffffffa00b80d7>] ? journal_start+0x8c/0xbd [jbd]
kernel: [<ffffffffa00db7e1>] ext3_tmpfile+0xb2/0x13b [ext3]
kernel: [<ffffffff821076f8>] path_openat+0x11f/0x5e7
kernel: [<ffffffff821c86b4>] ? list_del+0x11/0x30
kernel: [<ffffffff82065fa2>] ? __dequeue_entity+0x33/0x38
kernel: [<ffffffff82107cd5>] do_filp_open+0x3f/0x8d
kernel: [<ffffffff82112532>] ? __alloc_fd+0x50/0x102
kernel: [<ffffffff820f9296>] do_sys_open+0x13b/0x1cd
kernel: [<ffffffff820f935c>] SyS_open+0x1e/0x20
kernel: [<ffffffff82398c02>] system_call_fastpath+0x16/0x1b
kernel: Code: 39 c7 0f 85 67 01 00 00 0f b7 03 25 00 f0 00 00 3d 00 40 00 00 74 18 3d 00 80 00 00 74 11 3d 00 a0 00 00 74 0a 83 7b 48 00 74 04 <0f> 0b eb fe 49 8b 85 50 03 00 00 4c 89 f6 48 c7 c7 c0 99 0e a0
kernel: RIP [<ffffffffa00db5ae>] ext3_orphan_add+0x6a/0x1eb [ext3]
kernel: RSP <ffff8801124d5cc8>
Here we couldn't call clear_nlink() directly because in d_tmpfile() we
will call inode_dec_link_count() to decrease ->i_nlink. So this commit
tries to call d_tmpfile() before ext4_orphan_add() to fix this problem.
Signed-off-by: Zheng Liu <wenqing.lz@taobao.com>
Signed-off-by: "Theodore Ts'o" <tytso@mit.edu>
Cc: Jan Kara <jack@suse.cz>
Cc: Al Viro <viro@zeniv.linux.org.uk>
|
|
When we try to open a file with O_TMPFILE flag, we will trigger a bug.
The root cause is that in ext4_orphan_add() we check ->i_nlink == 0 and
this check always fails because we set ->i_nlink = 1 in
inode_init_always(). We can use the following program to trigger it:
int main(int argc, char *argv[])
{
int fd;
fd = open(argv[1], O_TMPFILE, 0666);
if (fd < 0) {
perror("open ");
return -1;
}
close(fd);
return 0;
}
The oops message looks like this:
kernel BUG at fs/ext4/namei.c:2572!
invalid opcode: 0000 [#1] PREEMPT SMP DEBUG_PAGEALLOC
Modules linked in: dlci bridge stp hidp cmtp kernelcapi l2tp_ppp l2tp_netlink l2tp_core sctp libcrc32c rfcomm tun fuse nfnetli
nk can_raw ipt_ULOG can_bcm x25 scsi_transport_iscsi ipx p8023 p8022 appletalk phonet psnap vmw_vsock_vmci_transport af_key vmw_vmci rose vsock atm can netrom ax25 af_rxrpc ir
da pppoe pppox ppp_generic slhc bluetooth nfc rfkill rds caif_socket caif crc_ccitt af_802154 llc2 llc snd_hda_codec_realtek snd_hda_intel snd_hda_codec serio_raw snd_pcm pcsp
kr edac_core snd_page_alloc snd_timer snd soundcore r8169 mii sr_mod cdrom pata_atiixp radeon backlight drm_kms_helper ttm
CPU: 1 PID: 1812571 Comm: trinity-child2 Not tainted 3.11.0-rc1+ #12
Hardware name: Gigabyte Technology Co., Ltd. GA-MA78GM-S2H/GA-MA78GM-S2H, BIOS F12a 04/23/2010
task: ffff88007dfe69a0 ti: ffff88010f7b6000 task.ti: ffff88010f7b6000
RIP: 0010:[<ffffffff8125ce69>] [<ffffffff8125ce69>] ext4_orphan_add+0x299/0x2b0
RSP: 0018:ffff88010f7b7cf8 EFLAGS: 00010202
RAX: 0000000000000000 RBX: ffff8800966d3020 RCX: 0000000000000000
RDX: 0000000000000000 RSI: ffff88007dfe70b8 RDI: 0000000000000001
RBP: ffff88010f7b7d40 R08: ffff880126a3c4e0 R09: ffff88010f7b7ca0
R10: 0000000000000000 R11: 0000000000000000 R12: ffff8801271fd668
R13: ffff8800966d2f78 R14: ffff88011d7089f0 R15: ffff88007dfe69a0
FS: 00007f70441a3740(0000) GS:ffff88012a800000(0000) knlGS:00000000f77c96c0
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 0000000002834000 CR3: 0000000107964000 CR4: 00000000000007e0
DR0: 0000000000780000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000ffff0ff0 DR7: 0000000000000600
Stack:
0000000000002000 00000020810b6dde 0000000000000000 ffff88011d46db00
ffff8800966d3020 ffff88011d7089f0 ffff88009c7f4c10 ffff88010f7b7f2c
ffff88007dfe69a0 ffff88010f7b7da8 ffffffff8125cfac ffff880100000004
Call Trace:
[<ffffffff8125cfac>] ext4_tmpfile+0x12c/0x180
[<ffffffff811cba78>] path_openat+0x238/0x700
[<ffffffff8100afc4>] ? native_sched_clock+0x24/0x80
[<ffffffff811cc647>] do_filp_open+0x47/0xa0
[<ffffffff811db73f>] ? __alloc_fd+0xaf/0x200
[<ffffffff811ba2e4>] do_sys_open+0x124/0x210
[<ffffffff81010725>] ? syscall_trace_enter+0x25/0x290
[<ffffffff811ba3ee>] SyS_open+0x1e/0x20
[<ffffffff816ca8d4>] tracesys+0xdd/0xe2
[<ffffffff81001001>] ? start_thread_common.constprop.6+0x1/0xa0
Code: 04 00 00 00 89 04 24 31 c0 e8 c4 77 04 00 e9 43 fe ff ff 66 25 00 d0 66 3d 00 80 0f 84 0e fe ff ff 83 7b 48 00 0f 84 04 fe ff ff <0f> 0b 49 8b 8c 24 50 07 00 00 e9 88 fe ff ff 0f 1f 84 00 00 00
Here we couldn't call clear_nlink() directly because in d_tmpfile() we
will call inode_dec_link_count() to decrease ->i_nlink. So this commit
tries to call d_tmpfile() before ext4_orphan_add() to fix this problem.
Reported-by: Dave Jones <davej@redhat.com>
Signed-off-by: Zheng Liu <wenqing.lz@taobao.com>
Tested-by: Darrick J. Wong <darrick.wong@oracle.com>
Tested-by: Dave Jones <davej@redhat.com>
Signed-off-by: "Theodore Ts'o" <tytso@mit.edu>
Acked-by: Al Viro <viro@zeniv.linux.org.uk>
|
|
git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs
Pull vfs fixes from Al Viro:
"The sget() one is a long-standing bug and will need to go into -stable
(in fact, it had been originally caught in RHEL6), the other two are
3.11-only"
* 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs:
vfs: constify dentry parameter in d_count()
livelock avoidance in sget()
allow O_TMPFILE to work with O_WRONLY
|
|
git://git.kernel.org/pub/scm/linux/kernel/git/tytso/ext4
Pull ext4 bugfixes from Ted Ts'o:
"Fixes for 3.11-rc2, sent at 5pm, in the professoinal style. :-)"
I'm not sure I like this new level of "professionalism".
9-5, people, 9-5.
* tag 'ext4_for_linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tytso/ext4:
ext4: call ext4_es_lru_add() after handling cache miss
ext4: yield during large unlinks
ext4: make the extent_status code more robust against ENOMEM failures
ext4: simplify calculation of blocks to free on error
ext4: fix error handling in ext4_ext_truncate()
|
|
Pull NFS client bugfixes from Trond Myklebust:
- Fix a regression against NFSv4 FreeBSD servers when creating a new
file
- Fix another regression in rpc_client_register()
* tag 'nfs-for-3.11-3' of git://git.linux-nfs.org/projects/trondmy/linux-nfs:
NFSv4: Fix a regression against the FreeBSD server
SUNRPC: Fix another issue with rpc_client_register()
|
|
git://git.kernel.org/pub/scm/linux/kernel/git/josef/btrfs-next
Pull btrfs fixes from Josef Bacik:
"I'm playing the role of Chris Mason this week while he's on vacation.
There are a few critical fixes for btrfs here, all regressions and
have been tested well"
* 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/josef/btrfs-next:
Btrfs: fix wrong write offset when replacing a device
Btrfs: re-add root to dead root list if we stop dropping it
Btrfs: fix lock leak when resuming snapshot deletion
Btrfs: update drop progress before stopping snapshot dropping
|
|
Eric Sandeen has found a nasty livelock in sget() - take a mount(2) about
to fail. The superblock is on ->fs_supers, ->s_umount is held exclusive,
->s_active is 1. Along comes two more processes, trying to mount the same
thing; sget() in each is picking that superblock, bumping ->s_count and
trying to grab ->s_umount. ->s_active is 3 now. Original mount(2)
finally gets to deactivate_locked_super() on failure; ->s_active is 2,
superblock is still ->fs_supers because shutdown will *not* happen until
->s_active hits 0. ->s_umount is dropped and now we have two processes
chasing each other:
s_active = 2, A acquired ->s_umount, B blocked
A sees that the damn thing is stillborn, does deactivate_locked_super()
s_active = 1, A drops ->s_umount, B gets it
A restarts the search and finds the same superblock. And bumps it ->s_active.
s_active = 2, B holds ->s_umount, A blocked on trying to get it
... and we are in the earlier situation with A and B switched places.
The root cause, of course, is that ->s_active should not grow until we'd
got MS_BORN. Then failing ->mount() will have deactivate_locked_super()
shut the damn thing down. Fortunately, it's easy to do - the key point
is that grab_super() is called only for superblocks currently on ->fs_supers,
so it can bump ->s_count and grab ->s_umount first, then check MS_BORN and
bump ->s_active; we must never increment ->s_count for superblocks past
->kill_sb(), but grab_super() is never called for those.
The bug is pretty old; we would've caught it by now, if not for accidental
exclusion between sget() for block filesystems; the things like cgroup or
e.g. mtd-based filesystems don't have anything of that sort, so they get
bitten. The right way to deal with that is obviously to fix sget()...
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
|
|
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
|
