- 04 7月, 2014 1 次提交
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由 Ian Kent 提交于
On strict build environments we can see: fs/autofs4/inode.c: In function 'autofs4_fill_super': fs/autofs4/inode.c:312: error: 'pgrp' may be used uninitialized in this function make[2]: *** [fs/autofs4/inode.o] Error 1 make[1]: *** [fs/autofs4] Error 2 make: *** [fs] Error 2 make: *** Waiting for unfinished jobs.... This is due to the use of pgrp_set being used to indicate pgrp has has been set rather than initializing pgrp itself. Signed-off-by: NIan Kent <raven@themaw.net> Signed-off-by: NAndrew Morton <akpm@linux-foundation.org> Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>
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- 05 6月, 2014 1 次提交
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由 Fabian Frederick 提交于
autofs_dev_ioctl_init is only called by __init init_autofs4_fs Signed-off-by: NFabian Frederick <fabf@skynet.be> Acked-by: NIan Kent <raven@themaw.net> Signed-off-by: NAndrew Morton <akpm@linux-foundation.org> Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>
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- 07 5月, 2014 1 次提交
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由 Ian Kent 提交于
autofs needs to be able to see private data dentry flags for its dentrys that are being created but not yet hashed and for its dentrys that have been rmdir()ed but not yet freed. It needs to do this so it can block processes in these states until a status has been returned to indicate the given operation is complete. It does this by keeping two lists, active and expring, of dentrys in this state and uses ->d_release() to keep them stable while it checks the reference count to determine if they should be used. But with the recent lockref changes dentrys being freed sometimes don't transition to a reference count of 0 before being freed so autofs can occassionally use a dentry that is invalid which can lead to a panic. Signed-off-by: NIan Kent <raven@themaw.net> Cc: Al Viro <viro@zeniv.linux.org.uk> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: <stable@vger.kernel.org> Signed-off-by: NAndrew Morton <akpm@linux-foundation.org> Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>
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- 09 4月, 2014 1 次提交
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由 Sasha Levin 提交于
There wasn't any check of the size passed from userspace before trying to allocate the memory required. This meant that userspace might request more space than allowed, triggering an OOM. Signed-off-by: NSasha Levin <sasha.levin@oracle.com> Signed-off-by: NIan Kent <raven@themaw.net> Signed-off-by: NAndrew Morton <akpm@linux-foundation.org> Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>
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- 24 1月, 2014 5 次提交
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由 Ian Kent 提交于
The autofs4 module doesn't consider symlinks for expire as it did in the older autofs v3 module (so it's actually a long standing regression). The user space daemon has focused on the use of bind mounts instead of symlinks for a long time now and that's why this has not been noticed. But with the future addition of amd map parsing to automount(8), not to mention amd itself (of am-utils), symlink expiry will be needed. The direct and offset mount types can't be symlinks and the tree mounts of version 4 were always real mounts so only indirect mounts need expire symlinks. Since the current users of the autofs4 module haven't reported this as a problem to date this patch probably isn't a candidate for backport to stable. Signed-off-by: NIan Kent <ikent@redhat.com> Signed-off-by: NAndrew Morton <akpm@linux-foundation.org> Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>
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由 Rui Xiang 提交于
Use the helper macro !IS_ROOT to replace parent != dentry->d_parent. Just clean up. Signed-off-by: NRui Xiang <rui.xiang@huawei.com> Signed-off-by: NIan Kent <raven@themaw.net> Signed-off-by: NAndrew Morton <akpm@linux-foundation.org> Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>
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由 Rui Xiang 提交于
While kzallocing sbi/ino fails, it should return -ENOMEM. And it should return the err value from autofs_prepare_pipe. Signed-off-by: NRui Xiang <rui.xiang@huawei.com> Signed-off-by: NIan Kent <raven@themaw.net> Signed-off-by: NAndrew Morton <akpm@linux-foundation.org> Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>
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由 Miklos Szeredi 提交于
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: NMiklos Szeredi <mszeredi@suse.cz> Acked-by: NSerge Hallyn <serge.hallyn@canonical.com> Cc: Eric Biederman <ebiederm@xmission.com> Acked-by: NIan Kent <raven@themaw.net> Cc: Oleg Nesterov <oleg@redhat.com> Signed-off-by: NAndrew Morton <akpm@linux-foundation.org> Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>
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由 Sukadev Bhattiprolu 提交于
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: NSukadev Bhattiprolu <sukadev@us.ibm.com> Signed-off-by: NMiklos Szeredi <mszeredi@suse.cz> Acked-by: NSerge Hallyn <serge.hallyn@canonical.com> Cc: Eric Biederman <ebiederm@xmission.com> Acked-by: NIan Kent <raven@themaw.net> Cc: Oleg Nesterov <oleg@redhat.com> Signed-off-by: NAndrew Morton <akpm@linux-foundation.org> Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>
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- 25 10月, 2013 2 次提交
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由 Al Viro 提交于
makes ->d_managed() safety in RCU mode independent from vfsmount_lock Signed-off-by: NAl Viro <viro@zeniv.linux.org.uk>
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由 Al Viro 提交于
Signed-off-by: NAl Viro <viro@zeniv.linux.org.uk>
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- 17 9月, 2013 1 次提交
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由 Al Viro 提交于
Don't drop ->wq_mutex before calling autofs4_notify_daemon() only to regain it there. Besides being pointless, that opens a race window where autofs4_wait_release() could've come and freed wq->name.name. And do the debugging printk in the "reused an existing wq" case before dropping ->wq_mutex - the same reason... Signed-off-by: NAl Viro <viro@zeniv.linux.org.uk> Acked-by: NIan Kent <raven@themaw.net>
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- 09 9月, 2013 1 次提交
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由 Ian Kent 提交于
When reconnecting to automounts at startup an autofs ioctl is used to find the device and inode of existing mounts so they can be used to open a file descriptor of possibly covered mounts. At this time the the caller might not yet "own" the mount so it can trigger calling ->d_automount(). This causes automount to hang when trying to reconnect to direct or offset mount types. Consequently kern_path() can't be used but kern_path_mountpoint() can be. Signed-off-by: NIan Kent <raven@themaw.net> Cc: Jeff Layton <jlayton@redhat.com> Cc: Al Viro <viro@ZenIV.linux.org.uk> Signed-off-by: NAl Viro <viro@zeniv.linux.org.uk>
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- 05 7月, 2013 1 次提交
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由 Al Viro 提交于
Signed-off-by: NAl Viro <viro@zeniv.linux.org.uk>
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- 29 6月, 2013 1 次提交
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由 Al Viro 提交于
new helpers - dir_emit_dot(file, ctx, dentry), dir_emit_dotdot(file, ctx), dir_emit_dots(file, ctx). Signed-off-by: NAl Viro <viro@zeniv.linux.org.uk>
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- 07 5月, 2013 2 次提交
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由 David Jeffery 提交于
When checking if an autofs mount point is busy it isn't sufficient to only check if it's a mount point. For example, if the mount of an offset mountpoint in a tree is denied for this host by its export and the dentry becomes a process working directory the check incorrectly returns the mount as not in use at expire. This can happen since the default when mounting within a tree is nostrict, which means ingnore mount fails on mounts within the tree and continue. The nostrict option is meant to allow mounting in this case. Signed-off-by: NDavid Jeffery <djeffery@redhat.com> Signed-off-by: NIan Kent <raven@themaw.net> Cc: stable@vger.kernel.org Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>
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由 Claudiu Ghioc 提交于
Fixed the sparse warning: fs/autofs4/root.c:411:5: warning: symbol 'autofs4_d_manage' was not declared. Should it be static?" [ Clearly it should be static as the function is declared static at the top of root.c. - imk ] Signed-off-by: NClaudiu Ghioc <claudiu.ghioc@gmail.com> Signed-off-by: NIan Kent <raven@themaw.net> Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>
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- 04 3月, 2013 1 次提交
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由 Eric W. Biederman 提交于
Modify the request_module to prefix the file system type with "fs-" and add aliases to all of the filesystems that can be built as modules to match. A common practice is to build all of the kernel code and leave code that is not commonly needed as modules, with the result that many users are exposed to any bug anywhere in the kernel. Looking for filesystems with a fs- prefix limits the pool of possible modules that can be loaded by mount to just filesystems trivially making things safer with no real cost. Using aliases means user space can control the policy of which filesystem modules are auto-loaded by editing /etc/modprobe.d/*.conf with blacklist and alias directives. Allowing simple, safe, well understood work-arounds to known problematic software. This also addresses a rare but unfortunate problem where the filesystem name is not the same as it's module name and module auto-loading would not work. While writing this patch I saw a handful of such cases. The most significant being autofs that lives in the module autofs4. This is relevant to user namespaces because we can reach the request module in get_fs_type() without having any special permissions, and people get uncomfortable when a user specified string (in this case the filesystem type) goes all of the way to request_module. After having looked at this issue I don't think there is any particular reason to perform any filtering or permission checks beyond making it clear in the module request that we want a filesystem module. The common pattern in the kernel is to call request_module() without regards to the users permissions. In general all a filesystem module does once loaded is call register_filesystem() and go to sleep. Which means there is not much attack surface exposed by loading a filesytem module unless the filesystem is mounted. In a user namespace filesystems are not mounted unless .fs_flags = FS_USERNS_MOUNT, which most filesystems do not set today. Acked-by: NSerge Hallyn <serge.hallyn@canonical.com> Acked-by: NKees Cook <keescook@chromium.org> Reported-by: NKees Cook <keescook@google.com> Signed-off-by: N"Eric W. Biederman" <ebiederm@xmission.com>
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- 02 3月, 2013 2 次提交
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由 Tim Gardner 提交于
smatch analysis: fs/autofs4/waitq.c:46 autofs4_catatonic_mode() info: redundant null check on wq->name.name calling kfree() Signed-off-by: NTim Gardner <tim.gardner@canonical.com> Signed-off-by: NIan Kent <raven@themaw.net> Cc: autofs@vger.kernel.org Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>
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由 Peter Huewe 提交于
autofs - Fix sparse warning: context imbalance in autofs4_d_automount() different lock contexts for basic block Sparse complains: fs/autofs4/root.c:409:9: sparse: context imbalance in 'autofs4_d_automount' - different lock contexts for basic block This was introduced by commit f55fb0c2 ("autofs4 - dont clear DCACHE_NEED_AUTOMOUNT on rootless mount") The function autofs4_d_automount can be left with the (&sbi->fs_lock) held if sbi->version <= 4 and simple_empty(dentry) == false so the warning seems valid. --> Add an spin_unlock in this case before we jump to done Unfortunately compile tested only. Reported-by: NFengguang Wu <fengguang.wu@intel.com> Signed-off-by: NPeter Huewe <peterhuewe@gmx.de> Acked-by: NIan Kent <raven@themaw.net> Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>
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- 26 2月, 2013 1 次提交
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由 Zhao Hongjiang 提交于
According to SUSv3: [EACCES] Permission denied. An attempt was made to access a file in a way forbidden by its file access permissions. [EPERM] Operation not permitted. An attempt was made to perform an operation limited to processes with appropriate privileges or to the owner of a file or other resource. So -EPERM should be returned if capability checks fails. Strictly speaking this is an API change since the error code user sees is altered. Signed-off-by: NZhao Hongjiang <zhaohongjiang@huawei.com> Acked-by: NJan Kara <jack@suse.cz> Acked-by: NSteven Whitehouse <swhiteho@redhat.com> Acked-by: NIan Kent <raven@themaw.net> Cc: Al Viro <viro@zeniv.linux.org.uk> Signed-off-by: NAndrew Morton <akpm@linux-foundation.org> Signed-off-by: NAl Viro <viro@zeniv.linux.org.uk>
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- 23 2月, 2013 1 次提交
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由 Al Viro 提交于
Signed-off-by: NAl Viro <viro@zeniv.linux.org.uk>
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- 14 12月, 2012 2 次提交
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由 Ian Kent 提交于
For direct (and offset) mounts, if an automounted mount is manually umounted the trigger mount dentry can appear non-empty causing it to not trigger mounts. This can also happen if there is a file handle leak in a user space automounting application. This happens because, when a ioctl control file handle is opened on the mount, a cursor dentry is created which causes list_empty() to see the dentry as non-empty. Since there is a case where listing the directory of these dentrys is needed, the use of dcache_dir_*() functions for .open() and .release() is needed. Consequently simple_empty() must be used instead of list_empty() when checking for an empty directory. Signed-off-by: NIan Kent <raven@themaw.net> Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>
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由 Ian Kent 提交于
The DCACHE_NEED_AUTOMOUNT flag is cleared on mount and set on expire for autofs rootless multi-mount dentrys to prevent unnecessary calls to ->d_automount(). Since DCACHE_MANAGE_TRANSIT is always set on autofs dentrys ->d_managed() is always called so the check can be done in ->d_manage() without the need to change the flag. This still avoids unnecessary calls to ->d_automount(), adds negligible overhead and eliminates a seriously ugly check in the expire code. Signed-off-by: NIan Kent <raven@themaw.net> Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>
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- 15 11月, 2012 1 次提交
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由 Eric W. Biederman 提交于
Use kuid_t and kgid_t in struct autofs_info and struct autofs_wait_queue. When creating directories and symlinks default the uid and gid of the mount requester to the global root uid and gid. autofs4_wait will update these fields when a mount is requested. When generating autofsv5 packets report the uid and gid of the mount requestor in user namespace of the process that opened the pipe, reporting unmapped uids and gids as overflowuid and overflowgid. In autofs_dev_ioctl_requester return the uid and gid of the last mount requester converted into the calling processes user namespace. When the uid or gid don't map return overflowuid and overflowgid as appropriate, allowing failure to find a mount requester to be distinguished from failure to map a mount requester. The uid and gid mount options specifying the user and group of the root autofs inode are converted into kuid and kgid as they are parsed defaulting to the current uid and current gid of the process that mounts autofs. Mounting of autofs for the present remains confined to processes in the initial user namespace. Cc: Ian Kent <raven@themaw.net> Acked-by: NSerge Hallyn <serge.hallyn@canonical.com> Signed-off-by: NEric W. Biederman <ebiederm@xmission.com>
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- 11 10月, 2012 1 次提交
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由 Ian Kent 提交于
In autofs4_d_automount(), if a mount fail occurs the AUTOFS_INF_PENDING mount pending flag is not cleared. One effect of this is when using the "browse" option, directory entry attributes show up with all "?"s due to the incorrect callback and subsequent failure return (when in fact no callback should be made). Signed-off-by: NIan Kent <ikent@redhat.com> Cc: stable@vger.kernel.org Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>
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- 27 9月, 2012 2 次提交
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由 Al Viro 提交于
simplifies a bunch of callers... Signed-off-by: NAl Viro <viro@zeniv.linux.org.uk>
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由 Al Viro 提交于
The only difference between autofs_dev_ioctl_fd_install() and fd_install() is __set_close_on_exec() done by the latter. Just use get_unused_fd_flags(O_CLOEXEC) to allocate the descriptor and be done with that... Signed-off-by: NAl Viro <viro@zeniv.linux.org.uk>
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- 17 8月, 2012 2 次提交
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由 Ian Kent 提交于
In some cases when an autofs indirect mount is contained in a file system that is marked as shared (such as when systemd does the equivalent of "mount --make-rshared /" early in the boot), mounts stop expiring. When this happens the first expiry check on a mountpoint dentry in autofs_expire_indirect() sees a mountpoint dentry with a higher than minimal reference count. Consequently the dentry is condidered busy and the actual expiry check is never done. This particular check was originally meant as an optimisation to detect a path walk in progress but with the addition of rcu-walk it can be ineffective anyway. Removing the test allows automounts to expire again since the actual expire check doesn't rely on the dentry reference count. Signed-off-by: NIan Kent <raven@themaw.net> Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>
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由 Ian Kent 提交于
Following a report of a crash during an automount expire I found that the locking in fs/autofs4/expire.c:get_next_positive_subdir() was wrong. Not only is the locking wrong but the function is more complex than it needs to be. The function is meant to calculate (and dget) the next entry in the list of directories contained in the root of an autofs mount point (an autofs indirect mount to be precise). The main problem was that the d_lock of the owner of the list was not being taken when walking the list, which lead to list corruption under load. The only other lock that needs to be taken is against the next dentry candidate so it can be checked for usability. Signed-off-by: NIan Kent <raven@themaw.net> Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>
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- 23 7月, 2012 1 次提交
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由 Al Viro 提交于
Signed-off-by: NAl Viro <viro@zeniv.linux.org.uk>
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- 14 7月, 2012 1 次提交
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由 Al Viro 提交于
Just the flags; only NFS cares even about that, but there are legitimate uses for such argument. And getting rid of that completely would require splitting ->lookup() into a couple of methods (at least), so let's leave that alone for now... Signed-off-by: NAl Viro <viro@zeniv.linux.org.uk>
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- 06 5月, 2012 1 次提交
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由 Jan Kara 提交于
After we moved inode_sync_wait() from end_writeback() it doesn't make sense to call the function end_writeback() anymore. Rename it to clear_inode() which well says what the function really does - set I_CLEAR flag. Signed-off-by: NJan Kara <jack@suse.cz> Signed-off-by: NFengguang Wu <fengguang.wu@intel.com>
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- 30 4月, 2012 1 次提交
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由 Linus Torvalds 提交于
The autofs packet size has had a very unfortunate size problem on x86: because the alignment of 'u64' differs in 32-bit and 64-bit modes, and because the packet data was not 8-byte aligned, the size of the autofsv5 packet structure differed between 32-bit and 64-bit modes despite looking otherwise identical (300 vs 304 bytes respectively). We first fixed that up by making the 64-bit compat mode know about this problem in commit a32744d4 ("autofs: work around unhappy compat problem on x86-64"), and that made a 32-bit 'systemd' work happily on a 64-bit kernel because everything then worked the same way as on a 32-bit kernel. But it turned out that 'automount' had actually known and worked around this problem in user space, so fixing the kernel to do the proper 32-bit compatibility handling actually *broke* 32-bit automount on a 64-bit kernel, because it knew that the packet sizes were wrong and expected those incorrect sizes. As a result, we ended up reverting that compatibility mode fix, and thus breaking systemd again, in commit fcbf94b9. With both automount and systemd doing a single read() system call, and verifying that they get *exactly* the size they expect but using different sizes, it seemed that fixing one of them inevitably seemed to break the other. At one point, a patch I seriously considered applying from Michael Tokarev did a "strcmp()" to see if it was automount that was doing the operation. Ugly, ugly. However, a prettier solution exists now thanks to the packetized pipe mode. By marking the communication pipe as being packetized (by simply setting the O_DIRECT flag), we can always just write the bigger packet size, and if user-space does a smaller read, it will just get that partial end result and the extra alignment padding will simply be thrown away. This makes both automount and systemd happy, since they now get the size they asked for, and the kernel side of autofs simply no longer needs to care - it could pad out the packet arbitrarily. Of course, if there is some *other* user of autofs (please, please, please tell me it ain't so - and we haven't heard of any) that tries to read the packets with multiple writes, that other user will now be broken - the whole point of the packetized mode is that one system call gets exactly one packet, and you cannot read a packet in pieces. Tested-by: NMichael Tokarev <mjt@tls.msk.ru> Cc: Alan Cox <alan@lxorguk.ukuu.org.uk> Cc: David Miller <davem@davemloft.net> Cc: Ian Kent <raven@themaw.net> Cc: Thomas Meyer <thomas@m3y3r.de> Cc: stable@kernel.org Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>
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- 28 4月, 2012 1 次提交
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由 Linus Torvalds 提交于
This reverts commit a32744d4. While that commit was technically the right thing to do, and made the x86-64 compat mode work identically to native 32-bit mode (and thus fixing the problem with a 32-bit systemd install on a 64-bit kernel), it turns out that the automount binaries had workarounds for this compat problem. Now, the workarounds are disgusting: doing an "uname()" to find out the architecture of the kernel, and then comparing it for the 64-bit cases and fixing up the size of the read() in automount for those. And they were confused: it's not actually a generic 64-bit issue at all, it's very much tied to just x86-64, which has different alignment for an 'u64' in 64-bit mode than in 32-bit mode. But the end result is that fixing the compat layer actually breaks the case of a 32-bit automount on a x86-64 kernel. There are various approaches to fix this (including just doing a "strcmp()" on current->comm and comparing it to "automount"), but I think that I will do the one that teaches pipes about a special "packet mode", which will allow user space to not have to care too deeply about the padding at the end of the autofs packet. That change will make the compat workaround unnecessary, so let's revert it first, and get automount working again in compat mode. The packetized pipes will then fix autofs for systemd. Reported-and-requested-by: NMichael Tokarev <mjt@tls.msk.ru> Cc: Ian Kent <raven@themaw.net> Cc: stable@kernel.org # for 3.3 Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>
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- 21 3月, 2012 2 次提交
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由 Al Viro 提交于
it's not a serious race, but we really want misc device before anybody gets to mount this sucker. Signed-off-by: NAl Viro <viro@zeniv.linux.org.uk>
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由 Al Viro 提交于
Signed-off-by: NAl Viro <viro@zeniv.linux.org.uk>
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- 26 2月, 2012 1 次提交
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由 Ian Kent 提交于
When the autofs protocol version 5 packet type was added in commit 5c0a32fc ("autofs4: add new packet type for v5 communications"), it obvously tried quite hard to be word-size agnostic, and uses explicitly sized fields that are all correctly aligned. However, with the final "char name[NAME_MAX+1]" array at the end, the actual size of the structure ends up being not very well defined: because the struct isn't marked 'packed', doing a "sizeof()" on it will align the size of the struct up to the biggest alignment of the members it has. And despite all the members being the same, the alignment of them is different: a "__u64" has 4-byte alignment on x86-32, but native 8-byte alignment on x86-64. And while 'NAME_MAX+1' ends up being a nice round number (256), the name[] array starts out a 4-byte aligned. End result: the "packed" size of the structure is 300 bytes: 4-byte, but not 8-byte aligned. As a result, despite all the fields being in the same place on all architectures, sizeof() will round up that size to 304 bytes on architectures that have 8-byte alignment for u64. Note that this is *not* a problem for 32-bit compat mode on POWER, since there __u64 is 8-byte aligned even in 32-bit mode. But on x86, 32-bit and 64-bit alignment is different for 64-bit entities, and as a result the structure that has exactly the same layout has different sizes. So on x86-64, but no other architecture, we will just subtract 4 from the size of the structure when running in a compat task. That way we will write the properly sized packet that user mode expects. Not pretty. Sadly, this very subtle, and unnecessary, size difference has been encoded in user space that wants to read packets of *exactly* the right size, and will refuse to touch anything else. Reported-and-tested-by: NThomas Meyer <thomas@m3y3r.de> Signed-off-by: NIan Kent <raven@themaw.net> Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>
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- 20 2月, 2012 1 次提交
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由 David Howells 提交于
Wrap accesses to the fd_sets in struct fdtable (for recording open files and close-on-exec flags) so that we can move away from using fd_sets since we abuse the fd_set structs by not allocating the full-sized structure under normal circumstances and by non-core code looking at the internals of the fd_sets. The first abuse means that use of FD_ZERO() on these fd_sets is not permitted, since that cannot be told about their abnormal lengths. This introduces six wrapper functions for setting, clearing and testing close-on-exec flags and fd-is-open flags: void __set_close_on_exec(int fd, struct fdtable *fdt); void __clear_close_on_exec(int fd, struct fdtable *fdt); bool close_on_exec(int fd, const struct fdtable *fdt); void __set_open_fd(int fd, struct fdtable *fdt); void __clear_open_fd(int fd, struct fdtable *fdt); bool fd_is_open(int fd, const struct fdtable *fdt); Note that I've prepended '__' to the names of the set/clear functions because they require the caller to hold a lock to use them. Note also that I haven't added wrappers for looking behind the scenes at the the array. Possibly that should exist too. Signed-off-by: NDavid Howells <dhowells@redhat.com> Link: http://lkml.kernel.org/r/20120216174942.23314.1364.stgit@warthog.procyon.org.ukSigned-off-by: NH. Peter Anvin <hpa@zytor.com> Cc: Al Viro <viro@zeniv.linux.org.uk>
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- 14 2月, 2012 1 次提交
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由 Steven Rostedt 提交于
When recursing down the locks when traversing a tree/list in get_next_positive_dentry() or get_next_positive_subdir() a lock can change from being nested to being a parent which breaks lockdep. This patch tells lockdep about what we did. Signed-off-by: NSteven Rostedt <rostedt@goodmis.org> Acked-by: NIan Kent <raven@themaw.net> Signed-off-by: NAl Viro <viro@zeniv.linux.org.uk>
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