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* userns: Support autofs4 interacing with multiple user namespacesEric W. Biederman2012-11-141-9/+15
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | 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: Serge Hallyn <serge.hallyn@canonical.com> Signed-off-by: Eric W. Biederman <ebiederm@xmission.com>
* Merge tag 'writeback' of git://git.kernel.org/pub/scm/linux/kernel/git/wfg/linuxLinus Torvalds2012-05-281-1/+1
|\ | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Pull writeback tree from Wu Fengguang: "Mainly from Jan Kara to avoid iput() in the flusher threads." * tag 'writeback' of git://git.kernel.org/pub/scm/linux/kernel/git/wfg/linux: writeback: Avoid iput() from flusher thread vfs: Rename end_writeback() to clear_inode() vfs: Move waiting for inode writeback from end_writeback() to evict_inode() writeback: Refactor writeback_single_inode() writeback: Remove wb->list_lock from writeback_single_inode() writeback: Separate inode requeueing after writeback writeback: Move I_DIRTY_PAGES handling writeback: Move requeueing when I_SYNC set to writeback_sb_inodes() writeback: Move clearing of I_SYNC into inode_sync_complete() writeback: initialize global_dirty_limit fs: remove 8 bytes of padding from struct writeback_control on 64 bit builds mm: page-writeback.c: local functions should not be exposed globally
| * vfs: Rename end_writeback() to clear_inode()Jan Kara2012-05-061-1/+1
| | | | | | | | | | | | | | | | | | 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: Jan Kara <jack@suse.cz> Signed-off-by: Fengguang Wu <fengguang.wu@intel.com>
* | autofs: make the autofsv5 packet file descriptor use a packetized pipeLinus Torvalds2012-04-291-1/+1
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | 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 a32744d4abae ("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 fcbf94b9dedd. 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: Michael 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: Linus Torvalds <torvalds@linux-foundation.org>
* | Revert "autofs: work around unhappy compat problem on x86-64"Linus Torvalds2012-04-281-2/+0
|/ | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | This reverts commit a32744d4abae24572eff7269bc17895c41bd0085. 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: Michael Tokarev <mjt@tls.msk.ru> Cc: Ian Kent <raven@themaw.net> Cc: stable@kernel.org # for 3.3 Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* switch open-coded instances of d_make_root() to new helperAl Viro2012-03-201-8/+2
| | | | Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
* autofs: work around unhappy compat problem on x86-64Ian Kent2012-02-251-0/+2
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | When the autofs protocol version 5 packet type was added in commit 5c0a32fc2cd0 ("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: Thomas Meyer <thomas@m3y3r.de> Signed-off-by: Ian Kent <raven@themaw.net> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* autofs4: deal with autofs4_write/autofs4_write racesAl Viro2012-01-111-0/+1
| | | | | | | | | | | Just serialize the actual writing of packets into pipe on a new mutex, independent from everything else in the locking hierarchy. As soon as something has started feeding a piece of packet into the pipe to daemon, we *want* everything else about to try the same to wait until we are done. Acked-by: Ian Kent <raven@themaw.net> Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
* vfs: switch ->show_options() to struct dentry *Al Viro2012-01-061-3/+3
| | | | Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
* autofs4: propagate umode_tAl Viro2012-01-031-1/+1
| | | | Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
* filesystems: add set_nlink()Miklos Szeredi2011-11-021-1/+1
| | | | | | | | | Replace remaining direct i_nlink updates with a new set_nlink() updater function. Signed-off-by: Miklos Szeredi <mszeredi@suse.cz> Tested-by: Toshiyuki Okajima <toshi.okajima@jp.fujitsu.com> Signed-off-by: Christoph Hellwig <hch@lst.de>
* autofs4: clean ->d_release() and autofs4_free_ino() upAl Viro2011-01-181-4/+0
| | | | | | | | The latter is called only when both ino and dentry are about to be freed, so cleaning ->d_fsdata and ->dentry is pointless. Acked-by: Ian Kent <raven@themaw.net> Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
* autofs4: split autofs4_init_ino()Al Viro2011-01-181-22/+10
| | | | | | | | | split init_ino into new_ino and clean_ino; the former is what used to be init_ino(NULL, sbi), the latter is for cases where we passed non-NULL ino. Lose unused arguments. Acked-by: Ian Kent <raven@themaw.net> Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
* autofs4: autofs4_get_inode() doesn't need autofs_info * argument anymoreAl Viro2011-01-181-4/+2
| | | | | Acked-by: Ian Kent <raven@themaw.net> Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
* autofs4: kill ->size in autofs_infoAl Viro2011-01-181-2/+0
| | | | | | | | | | It's used only to pass the length of symlink body to autofs4_get_inode() in autofs4_dir_symlink(). We can bloody well set inode->i_size in autofs4_dir_symlink() directly and be done with that. Acked-by: Ian Kent <raven@themaw.net> Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
* autofs4: pass mode to autofs4_get_inode() explicitlyAl Viro2011-01-181-8/+8
| | | | | | | | | In all cases we'd set inf->mode to know value just before passing it to autofs4_get_inode(). That kills the need to store it in autofs_info and pass it to autofs_init_ino() Acked-by: Ian Kent <raven@themaw.net> Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
* autofs4: autofs4_mkroot() is not different from autofs4_init_ino()Al Viro2011-01-181-12/+1
| | | | | | | | Kill it. Mind you, it's been an obfuscated call of autofs4_init_ino() ever since 2.3.99pre6-4... Acked-by: Ian Kent <raven@themaw.net> Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
* autofs4: keep symlink body in inode->i_privateAl Viro2011-01-181-20/+7
| | | | | | | | gets rid of all ->free()/->u.symlink machinery in autofs; we simply keep symlink bodies in inode->i_private and free them in ->evict_inode(). Acked-by: Ian Kent <raven@themaw.net> Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
* autofs4: Merge the remaining dentry ops tablesDavid Howells2011-01-151-4/+2
| | | | | | | | | | | | | Merge the remaining autofs4 dentry ops tables. It doesn't matter if d_automount and d_manage are present on something that's not mountable or holdable as these ops are only used if the appropriate flags are set in dentry->d_flags. [AV] switch to ->s_d_op, since now _everything_ on autofs4 is using the same dentry_operations. Signed-off-by: David Howells <dhowells@redhat.com> Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
* autofs4: Clean up autofs4_free_ino()Ian Kent2011-01-151-13/+0
| | | | | | | | | | | | When this function is called the local reference count does't need to be updated since the dentry is going away and dput definitely must not be called here. Also the autofs info struct field inode isn't used so remove it. Signed-off-by: Ian Kent <raven@themaw.net> Signed-off-by: David Howells <dhowells@redhat.com> Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
* autofs4: Clean up dentry operationsIan Kent2011-01-151-8/+4
| | | | | | | | | | | | There are now two distinct dentry operations uses. One for dentrys that trigger mounts and one for dentrys that do not. Rationalize the use of these dentry operations and rename them to reflect their function. Signed-off-by: Ian Kent <raven@themaw.net> Signed-off-by: David Howells <dhowells@redhat.com> Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
* autofs4: Clean up inode operationsIan Kent2011-01-151-3/+1
| | | | | | | | | Since the use of ->follow_link() has been eliminated there is no need to separate the indirect and direct inode operations. Signed-off-by: Ian Kent <raven@themaw.net> Signed-off-by: David Howells <dhowells@redhat.com> Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
* autofs4: Add d_manage() dentry operationIan Kent2011-01-151-1/+2
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | This patch required a previous patch to add the ->d_automount() dentry operation. Add a function to use the newly defined ->d_manage() dentry operation for blocking during mount and expire. Whether the VFS calls the dentry operations d_automount() and d_manage() is controled by the DMANAGED_AUTOMOUNT and DMANAGED_TRANSIT flags. autofs uses the d_automount() operation to callback to user space to request mount operations and the d_manage() operation to block walks into mounts that are under construction or destruction. In order to prevent these functions from being called unnecessarily the DMANAGED_* flags are cleared for cases which would cause this. In the common case the DMANAGED_AUTOMOUNT and DMANAGED_TRANSIT flags are both set for dentrys waiting to be mounted. The DMANAGED_TRANSIT flag is cleared upon successful mount request completion and set during expire runs, both during the dentry expire check, and if selected for expire, is left set until a subsequent successful mount request completes. The exception to this is the so-called rootless multi-mount which has no actual mount at its base. In this case the DMANAGED_AUTOMOUNT flag is cleared upon successful mount request completion as well and set again after a successful expire. Signed-off-by: Ian Kent <raven@themaw.net> Signed-off-by: David Howells <dhowells@redhat.com> Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
* autofs4: Add d_automount() dentry operationIan Kent2011-01-151-0/+4
| | | | | | | | | | | | | | Add a function to use the newly defined ->d_automount() dentry operation for triggering mounts instead of doing the user space callback in ->lookup() and ->d_revalidate(). Note, to be useful the subsequent patch to add the ->d_manage() dentry operation is also needed so the discussion of functionality is deferred to that patch. Signed-off-by: Ian Kent <raven@themaw.net> Signed-off-by: David Howells <dhowells@redhat.com> Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
* fs: dcache reduce branches in lookup pathNick Piggin2011-01-071-1/+1
| | | | | | | | | | | | | | Reduce some branches and memory accesses in dcache lookup by adding dentry flags to indicate common d_ops are set, rather than having to check them. This saves a pointer memory access (dentry->d_op) in common path lookup situations, and saves another pointer load and branch in cases where we have d_op but not the particular operation. Patched with: git grep -E '[.>]([[:space:]])*d_op([[:space:]])*=' | xargs sed -e 's/\([^\t ]*\)->d_op = \(.*\);/d_set_d_op(\1, \2);/' -e 's/\([^\t ]*\)\.d_op = \(.*\);/d_set_d_op(\&\1, \2);/' -i Signed-off-by: Nick Piggin <npiggin@kernel.dk>
* fs: do not assign default i_ino in new_inodeChristoph Hellwig2010-10-251-0/+1
| | | | | | | | | | | | | | | Instead of always assigning an increasing inode number in new_inode move the call to assign it into those callers that actually need it. For now callers that need it is estimated conservatively, that is the call is added to all filesystems that do not assign an i_ino by themselves. For a few more filesystems we can avoid assigning any inode number given that they aren't user visible, and for others it could be done lazily when an inode number is actually needed, but that's left for later patches. Signed-off-by: Christoph Hellwig <hch@lst.de> Signed-off-by: Dave Chinner <dchinner@redhat.com> Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
* Use kill_litter_super() in autofs4 ->kill_sb()Al Viro2010-03-031-61/+1
| | | | | | ... and get rid of open-coding its guts (i.e. RIP autofs4_force_release()) Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
* Revert "autofs4: always use lookup for lookup"Al Viro2010-03-031-1/+0
| | | | | | | | | | This reverts commit 213614d583748d00967a91cacd656f417efb36ce. Alas, ->d_revalidate() can't rely on ->lookup() finishing what it's started; if d_alloc() in do_lookup() fails, we are not going to call ->lookup() at all. Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
* autofs4: always use lookup for lookupIan Kent2009-12-161-0/+1
| | | | | | | | | | | | | | | | | We need to be able to cope with the directory mutex being held during ->d_revalidate() in some cases, but not all cases, and not necessarily by us. Because we need to release the mutex when we call back to the daemon to do perform a mount we must be sure that it is us who holds the mutex so we must redirect mount requests to ->lookup() if the mutex is held. Signed-off-by: Ian Kent <raven@themaw.net> Cc: Sage Weil <sage@newdream.net> Cc: Al Viro <viro@ZenIV.linux.org.uk> Cc: Andreas Dilger <adilger@sun.com> Cc: Christoph Hellwig <hch@infradead.org> Cc: Yehuda Saheh <yehuda@newdream.net> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* autofs4: use helper functions for active list handlingIan Kent2009-12-161-0/+1
| | | | | | | | | | | | | | Define some simple helper functions for adding and deleting entries on the active (and unhashed) dentry list. Signed-off-by: Ian Kent <raven@themaw.net> Cc: Sage Weil <sage@newdream.net> Cc: Al Viro <viro@ZenIV.linux.org.uk> Cc: Andreas Dilger <adilger@sun.com> Cc: Christoph Hellwig <hch@infradead.org> Cc: Yehuda Saheh <yehuda@newdream.net> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* constify dentry_operations: autofs, autofs4Al Viro2009-03-271-1/+1
| | | | Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
* autofs4: make autofs type usage explicitIan Kent2009-01-061-7/+7
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | - the type assigned at mount when no type is given is changed from 0 to AUTOFS_TYPE_INDIRECT. This was done because 0 and AUTOFS_TYPE_INDIRECT were being treated implicitly as the same type. - previously, an offset mount had it's type set to AUTOFS_TYPE_DIRECT|AUTOFS_TYPE_OFFSET but the mount control re-implementation needs to be able distinguish all three types. So this was changed to make the type setting explicit. - a type AUTOFS_TYPE_ANY was added for use by the re-implementation when checking if a given path is a mountpoint. It's not really a type as we use this to ask if a given path is a mountpoint in the autofs_dev_ioctl_ismountpoint() function. - functions to set and test the autofs mount types have been added to improve readability and make the type usage explicit. - the mount type is used from user space for the mount control re-implementtion so, for consistency, all the definitions have been moved to the user space include file include/linux/auto_fs4.h. Signed-off-by: Ian Kent <raven@themaw.net> Signed-off-by: Jeff Moyer <jmoyer@redhat.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* zero i_uid/i_gid on inode allocationAl Viro2009-01-051-4/+0
| | | | | | | | | ... and don't bother in callers. Don't bother with zeroing i_blocks, while we are at it - it's already been zeroed. i_mode is not worth the effort; it has no common default value. Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
* CRED: Wrap task credential accesses in the autofs4 filesystemDavid Howells2008-11-141-2/+2
| | | | | | | | | | | | | | | | | | Wrap access to task credentials so that they can be separated more easily from the task_struct during the introduction of COW creds. Change most current->(|e|s|fs)[ug]id to current_(|e|s|fs)[ug]id(). Change some task->e?[ug]id to task_e?[ug]id(). In some places it makes more sense to use RCU directly rather than a convenient wrapper; these will be addressed by later patches. Signed-off-by: David Howells <dhowells@redhat.com> Reviewed-by: James Morris <jmorris@namei.org> Acked-by: Serge Hallyn <serue@us.ibm.com> Cc: Ian Kent <raven@themaw.net> Cc: autofs@linux.kernel.org Signed-off-by: James Morris <jmorris@namei.org>
* autofs4: track uid and gid of last mount requesterIan Kent2008-10-161-0/+2
| | | | | | | | | | Track the uid and gid of the last process to request a mount for on an autofs dentry. [akpm@linux-foundation.org: fix tpyo in comment] Signed-off-by: Ian Kent <raven@themaw.net> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* autofs4: cleanup autofs mount type usageIan Kent2008-10-161-3/+3
| | | | | | | | | Usage of the AUTOFS_TYPE_* defines is a little confusing and appears inconsistent. Signed-off-by: Ian Kent <raven@themaw.net> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* vfs: Use const for kernel parser tableSteven Whitehouse2008-10-131-1/+1
| | | | | | | | | | | | | | This is a much better version of a previous patch to make the parser tables constant. Rather than changing the typedef, we put the "const" in all the various places where its required, allowing the __initconst exception for nfsroot which was the cause of the previous trouble. This was posted for review some time ago and I believe its been in -mm since then. Signed-off-by: Steven Whitehouse <swhiteho@redhat.com> Cc: Alexander Viro <aviro@redhat.com> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* autofs4: fix waitq lockingIan Kent2008-07-241-2/+2
| | | | | | | | | | | The autofs4_catatonic_mode() function accesses the wait queue without any locking but can be called at any time. This could lead to a possible double free of the name field of the wait and a double fput of the daemon communication pipe or an fput of a NULL file pointer. Signed-off-by: Ian Kent <raven@themaw.net> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* autofs4: use look aside list for lookupsIan Kent2008-07-241-10/+15
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | A while ago a patch to resolve a deadlock during directory creation was merged. This delayed the hashing of lookup dentrys until the ->mkdir() (or ->symlink()) operation completed to ensure we always went through ->lookup() instead of also having processes go through ->revalidate() so our VFS locking remained consistent. Now we are seeing a couple of side affects of that change in situations with heavy mount activity. Two cases have been identified: 1) When a mount request is triggered, due to the delayed hashing, the directory created by user space for the mount point doesn't have the DCACHE_AUTOFS_PENDING flag set. In the case of an autofs multi-mount where a tree of mount point directories are created this can lead to the path walk continuing rather than the dentry being sent to the wait queue to wait for request completion. This is because, if the pending flag isn't set, the criteria for deciding this is a mount in progress fails to hold, namely that the dentry is not a mount point and has no subdirectories. 2) A mount request dentry is initially created negative and unhashed. It remains this way until the ->mkdir() callback completes. Since it is unhashed a fresh dentry is used when the user space mount request creates the mount point directory. This leaves the original dentry negative and unhashed. But revalidate has no way to tell the VFS that the dentry has changed, other than to force another ->lookup() by returning false, which is at best wastefull and at worst not possible. This results in an -ENOENT return from the original path walk when in fact the mount succeeded. To resolve this we need to ensure that the same dentry is used in all calls to ->lookup() during the course of a mount request. This patch achieves that by adding the initial dentry to a look aside list and removes it at ->mkdir() or ->symlink() completion (or when the dentry is released), since these are the only create operations autofs4 supports. Signed-off-by: Ian Kent <raven@themaw.net> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* autofs4: don't make expiring dentry negativeIan Kent2008-07-241-3/+3
| | | | | | | | | | | | | | | | | | | Correct the error of making a positive dentry negative after it has been instantiated. The code that makes this error attempts to re-use the dentry from a concurrent expire and mount to resolve a race and the dentry used for the lookup must be negative for mounts to trigger in the required cases. The fact is that the dentry doesn't need to be re-used because all that is needed is to preserve the flag that indicates an expire is still incomplete at the time of the mount request. This change uses the the dentry to check the flag and wait for the expire to complete then discards it instead of attempting to re-use it. Signed-off-by: Ian Kent <raven@themaw.net> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* mount options: fix autofs4Miklos Szeredi2008-02-081-0/+5
| | | | | | | | | Add uid= and gid= options to /proc/mounts for autofs4 filesystems. Signed-off-by: Miklos Szeredi <mszeredi@suse.cz> Acked-by: Ian Kent <raven@themaw.net> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* pid namespaces: round up the APIPavel Emelianov2007-10-191-2/+2
| | | | | | | | | | | | | | | | | | | | | | | | | | The set of functions process_session, task_session, process_group and task_pgrp is confusing, as the names can be mixed with each other when looking at the code for a long time. The proposals are to * equip the functions that return the integer with _nr suffix to represent that fact, * and to make all functions work with task (not process) by making the common prefix of the same name. For monotony the routines signal_session() and set_signal_session() are replaced with task_session_nr() and set_task_session(), especially since they are only used with the explicit task->signal dereference. Signed-off-by: Pavel Emelianov <xemul@openvz.org> Acked-by: Serge E. Hallyn <serue@us.ibm.com> Cc: Kirill Korotaev <dev@openvz.org> Cc: "Eric W. Biederman" <ebiederm@xmission.com> Cc: Cedric Le Goater <clg@fr.ibm.com> Cc: Herbert Poetzl <herbert@13thfloor.at> Cc: Sukadev Bhattiprolu <sukadev@us.ibm.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* fs/autofs4/inode.c: kmalloc + memset conversion to kzallocMariusz Kozlowski2007-10-171-3/+1
| | | | | | | | | | fs/autofs4/inode.c | 10467 -> 10435 (-32 bytes) fs/autofs4/inode.o | 98576 -> 98552 (-24 bytes) Signed-off-by: Mariusz Kozlowski <m.kozlowski@tuxland.pl> Acked-by: Ian Kent <raven@themaw.net> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* Fix some coding-style errors in autofsSukadev Bhattiprolu2007-05-111-9/+7
| | | | | | | | | | | | | | | Fix coding style errors (extra spaces, long lines) in autofs and autofs4 files being modified for container/pidspace issues. Signed-off-by: Sukadev Bhattiprolu <sukadev@us.ibm.com> Cc: Cedric Le Goater <clg@fr.ibm.com> Cc: Dave Hansen <haveblue@us.ibm.com> Cc: Serge Hallyn <serue@us.ibm.com> Cc: <containers@lists.osdl.org> Cc: Eric W. Biederman <ebiederm@xmission.com> Cc: Ian Kent <raven@themaw.net> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* header cleaning: don't include smp_lock.h when not usedRandy Dunlap2007-05-081-1/+0
| | | | | | | | | | | | Remove includes of <linux/smp_lock.h> where it is not used/needed. Suggested by Al Viro. Builds cleanly on x86_64, i386, alpha, ia64, powerpc, sparc, sparc64, and arm (all 59 defconfigs). Signed-off-by: Randy Dunlap <randy.dunlap@oracle.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* [PATCH] autofs4: fix another race between mount and expireIan Kent2007-02-201-3/+6
| | | | | | | | | | | | | | | | | | | | | | Jeff Moyer has identified a race between mount and expire. What happens is that during an expire the situation can arise that a directory is removed and another lookup is done before the expire issues a completion status to the kernel module. In this case, since the the lookup gets a new dentry, it doesn't know that there is an expire in progress and when it posts its mount request, matches the existing expire request and waits for its completion. ENOENT is then returned to user space from lookup (as the dentry passed in is now unhashed) without having performed the mount request. The solution used here is to keep track of dentrys in this unhashed state and reuse them, if possible, in order to preserve the flags. Additionally, this infrastructure will provide the framework for the reintroduction of caching of mount fails removed earlier in development. Signed-off-by: Ian Kent <raven@themaw.net> Acked-by: Jeff Moyer <jmoyer@redhat.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* [PATCH] Mark struct super_operations constJosef 'Jeff' Sipek2007-02-121-1/+1
| | | | | | | | | | | This patch is inspired by Arjan's "Patch series to mark struct file_operations and struct inode_operations const". Compile tested with gcc & sparse. Signed-off-by: Josef 'Jeff' Sipek <jsipek@cs.sunysb.edu> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* [PATCH] getting rid of all casts of k[cmz]alloc() callsRobert P. J. Day2006-12-131-1/+1
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Run this: #!/bin/sh for f in $(grep -Erl "\([^\)]*\) *k[cmz]alloc" *) ; do echo "De-casting $f..." perl -pi -e "s/ ?= ?\([^\)]*\) *(k[cmz]alloc) *\(/ = \1\(/" $f done And then go through and reinstate those cases where code is casting pointers to non-pointers. And then drop a few hunks which conflicted with outstanding work. Cc: Russell King <rmk@arm.linux.org.uk>, Ian Molton <spyro@f2s.com> Cc: Mikael Starvik <starvik@axis.com> Cc: Yoshinori Sato <ysato@users.sourceforge.jp> Cc: Roman Zippel <zippel@linux-m68k.org> Cc: Geert Uytterhoeven <geert@linux-m68k.org> Cc: Ralf Baechle <ralf@linux-mips.org> Cc: Paul Mackerras <paulus@samba.org> Cc: Kyle McMartin <kyle@mcmartin.ca> Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org> Cc: Martin Schwidefsky <schwidefsky@de.ibm.com> Cc: "David S. Miller" <davem@davemloft.net> Cc: Jeff Dike <jdike@addtoit.com> Cc: Greg KH <greg@kroah.com> Cc: Jens Axboe <jens.axboe@oracle.com> Cc: Paul Fulghum <paulkf@microgate.com> Cc: Alan Cox <alan@lxorguk.ukuu.org.uk> Cc: Karsten Keil <kkeil@suse.de> Cc: Mauro Carvalho Chehab <mchehab@infradead.org> Cc: Jeff Garzik <jeff@garzik.org> Cc: James Bottomley <James.Bottomley@steeleye.com> Cc: Ian Kent <raven@themaw.net> Cc: Steven French <sfrench@us.ibm.com> Cc: David Woodhouse <dwmw2@infradead.org> Cc: Neil Brown <neilb@cse.unsw.edu.au> Cc: Jaroslav Kysela <perex@suse.cz> Cc: Takashi Iwai <tiwai@suse.de> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
* [PATCH] autofs: fix error code path in autofs_fill_sb()Jiri Kosina2006-12-071-3/+4
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | When kernel is compiled with old version of autofs (CONFIG_AUTOFS_FS), and new (observed at least with 5.x.x) automount deamon is started, kernel correctly reports incompatible version of kernel and userland daemon, but then screws things up instead of correct handling of the error: autofs: kernel does not match daemon version ===================================== [ BUG: bad unlock balance detected! ] ------------------------------------- automount/4199 is trying to release lock (&type->s_umount_key) at: [<c0163b9e>] get_sb_nodev+0x76/0xa4 but there are no more locks to release! other info that might help us debug this: no locks held by automount/4199. stack backtrace: [<c0103b15>] dump_trace+0x68/0x1b2 [<c0103c77>] show_trace_log_lvl+0x18/0x2c [<c01041db>] show_trace+0xf/0x11 [<c010424d>] dump_stack+0x12/0x14 [<c012e02c>] print_unlock_inbalance_bug+0xe7/0xf3 [<c012fd4f>] lock_release+0x8d/0x164 [<c012b452>] up_write+0x14/0x27 [<c0163b9e>] get_sb_nodev+0x76/0xa4 [<c0163689>] vfs_kern_mount+0x83/0xf6 [<c016373e>] do_kern_mount+0x2d/0x3e [<c017513f>] do_mount+0x607/0x67a [<c0175224>] sys_mount+0x72/0xa4 [<c0102b96>] sysenter_past_esp+0x5f/0x99 DWARF2 unwinder stuck at sysenter_past_esp+0x5f/0x99 Leftover inexact backtrace: ======================= and then deadlock comes. The problem: autofs_fill_super() returns EINVAL to get_sb_nodev(), but before that, it calls kill_anon_super() to destroy the superblock which won't be needed. This is however way too soon to call kill_anon_super(), because get_sb_nodev() has to perform its own cleanup of the superblock first (deactivate_super(), etc.). The correct time to call kill_anon_super() is in the autofs_kill_sb() callback, which is called by deactivate_super() at proper time, when the superblock is ready to be killed. I can see the same faulty codepath also in autofs4. This patch solves issues in both filesystems in a same way - it postpones the kill_anon_super() until the proper time is signalized by deactivate_super() calling the kill_sb() callback. [raven@themaw.net: update comment] Signed-off-by: Jiri Kosina <jkosina@suse.cz> Acked-by: Ian Kent <raven@themaw.net> Cc: <stable@kernel.org> Signed-off-by: Ian Kent <raven@themaw.net> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
* [PATCH] autofs4: panic after mount failIan Kent2006-11-141-1/+16
| | | | | | | | | | | | | | Resolve the panic on failed mount of an autofs filesystem originally reported by Mao Bibo. It addresses two issues that happen after the mount fail. The first a NULL pointer reference to a field (pipe) in the autofs superblock info structure and second the lack of super block cleanup by the autofs and autofs4 modules. Signed-off-by: Ian Kent <raven@themaw.net> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
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