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2012-01-06vfs: switch ->show_options() to struct dentry *Al Viro1-1/+1
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2012-01-03switch ->mknod() to umode_tAl Viro1-1/+1
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2012-01-03switch ->create() to umode_tAl Viro1-1/+1
vfs_create() ignores everything outside of 16bit subset of its mode argument; switching it to umode_t is obviously equivalent and it's the only caller of the method Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2012-01-03switch vfs_mkdir() and ->mkdir() to umode_tAl Viro1-1/+1
vfs_mkdir() gets int, but immediately drops everything that might not fit into umode_t and that's the only caller of ->mkdir()... Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2011-11-02vfs: add d_prune dentry operationSage Weil1-0/+1
This adds a d_prune dentry operation that is called by the VFS prior to pruning (i.e. unhashing and killing) a hashed dentry from the dcache. Wrap dentry_lru_del() and use the new _prune() helper in the cases where we are about to unhash and kill the dentry. This will be used by Ceph to maintain a flag indicating whether the complete contents of a directory are contained in the dcache, allowing it to satisfy lookups and readdir without addition server communication. Renumber a few DCACHE_* #defines to group DCACHE_OP_PRUNE with the other DCACHE_OP_ bits. Signed-off-by: Sage Weil <sage@newdream.net> Signed-off-by: Christoph Hellwig <hch@lst.de>
2011-07-25Merge branch 'for-3.1' of git://linux-nfs.org/~bfields/linuxLinus Torvalds1-12/+12
* 'for-3.1' of git://linux-nfs.org/~bfields/linux: nfsd: don't break lease on CLAIM_DELEGATE_CUR locks: rename lock-manager ops nfsd4: update nfsv4.1 implementation notes nfsd: turn on reply cache for NFSv4 nfsd4: call nfsd4_release_compoundargs from pc_release nfsd41: Deny new lock before RECLAIM_COMPLETE done fs: locks: remove init_once nfsd41: check the size of request nfsd41: error out when client sets maxreq_sz or maxresp_sz too small nfsd4: fix file leak on open_downgrade nfsd4: remember to put RW access on stateid destruction NFSD: Added TEST_STATEID operation NFSD: added FREE_STATEID operation svcrpc: fix list-corrupting race on nfsd shutdown rpc: allow autoloading of gss mechanisms svcauth_unix.c: quiet sparse noise svcsock.c: include sunrpc.h to quiet sparse noise nfsd: Remove deprecated nfsctl system call and related code. NFSD: allow OP_DESTROY_CLIENTID to be only op in COMPOUND Fix up trivial conflicts in Documentation/feature-removal-schedule.txt
2011-07-25fs: take the ACL checks to common codeChristoph Hellwig1-2/+2
Replace the ->check_acl method with a ->get_acl method that simply reads an ACL from disk after having a cache miss. This means we can replace the ACL checking boilerplate code with a single implementation in namei.c. Signed-off-by: Christoph Hellwig <hch@lst.de> Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2011-07-20fs: push i_mutex and filemap_write_and_wait down into ->fsync() handlersJosef Bacik1-4/+2
Btrfs needs to be able to control how filemap_write_and_wait_range() is called in fsync to make it less of a painful operation, so push down taking i_mutex and the calling of filemap_write_and_wait() down into the ->fsync() handlers. Some file systems can drop taking the i_mutex altogether it seems, like ext3 and ocfs2. For correctness sake I just pushed everything down in all cases to make sure that we keep the current behavior the same for everybody, and then each individual fs maintainer can make up their mind about what to do from there. Thanks, Acked-by: Jan Kara <jack@suse.cz> Signed-off-by: Josef Bacik <josef@redhat.com> Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2011-07-20locks: rename lock-manager opsJ. Bruce Fields1-12/+12
Both the filesystem and the lock manager can associate operations with a lock. Confusingly, one of them (fl_release_private) actually has the same name in both operation structures. It would save some confusion to give the lock-manager ops different names. Signed-off-by: J. Bruce Fields <bfields@redhat.com>
2011-07-20->permission() sanitizing: don't pass flags to ->check_acl()Al Viro1-1/+1
not used in the instances anymore. Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2011-05-27fs: pass exact type of data dirties to ->dirty_inodeChristoph Hellwig1-2/+2
Tell the filesystem if we just updated timestamp (I_DIRTY_SYNC) or anything else, so that the filesystem can track internally if it needs to push out a transaction for fdatasync or not. This is just the prototype change with no user for it yet. I plan to push large XFS changes for the next merge window, and getting this trivial infrastructure in this window would help a lot to avoid tree interdependencies. Also remove incorrect comments that ->dirty_inode can't block. That has been changed a long time ago, and many implementations rely on it. Signed-off-by: Christoph Hellwig <hch@lst.de> Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2011-03-24fs: remove inode_lock from iput_final and prune_icacheDave Chinner1-1/+1
Now that inode state changes are protected by the inode->i_lock and the inode LRU manipulations by the inode_lru_lock, we can remove the inode_lock from prune_icache and the initial part of iput_final(). instead of using the inode_lock to protect the inode during iput_final, use the inode->i_lock instead. This protects the inode against new references being taken while we change the inode state to I_FREEING, as well as preventing prune_icache from grabbing the inode while we are manipulating it. Hence we no longer need the inode_lock in iput_final prior to setting I_FREEING on the inode. For prune_icache, we no longer need the inode_lock to protect the LRU list, and the inodes themselves are protected against freeing races by the inode->i_lock. Hence we can lift the inode_lock from prune_icache as well. Signed-off-by: Dave Chinner <dchinner@redhat.com> Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2011-03-16vfs: bury ->get_sb()Al Viro1-4/+2
This is an ex-parrot. Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2011-01-17fallocate should be a file operationChristoph Hellwig1-2/+1
Currently all filesystems except XFS implement fallocate asynchronously, while XFS forced a commit. Both of these are suboptimal - in case of O_SYNC I/O we really want our allocation on disk, especially for the !KEEP_SIZE case where we actually grow the file with user-visible zeroes. On the other hand always commiting the transaction is a bad idea for fast-path uses of fallocate like for example in recent Samba versions. Given that block allocation is a data plane operation anyway change it from an inode operation to a file operation so that we have the file structure available that lets us check for O_SYNC. This also includes moving the code around for a few of the filesystems, and remove the already unnedded S_ISDIR checks given that we only wire up fallocate for regular files. Signed-off-by: Christoph Hellwig <hch@lst.de> Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2011-01-16Merge branch 'for-linus' of ↵Linus Torvalds1-0/+4
git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs-2.6 * 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs-2.6: (23 commits) sanitize vfsmount refcounting changes fix old umount_tree() breakage autofs4: Merge the remaining dentry ops tables Unexport do_add_mount() and add in follow_automount(), not ->d_automount() Allow d_manage() to be used in RCU-walk mode Remove a further kludge from __do_follow_link() autofs4: Bump version autofs4: Add v4 pseudo direct mount support autofs4: Fix wait validation autofs4: Clean up autofs4_free_ino() autofs4: Clean up dentry operations autofs4: Clean up inode operations autofs4: Remove unused code autofs4: Add d_manage() dentry operation autofs4: Add d_automount() dentry operation Remove the automount through follow_link() kludge code from pathwalk CIFS: Use d_automount() rather than abusing follow_link() NFS: Use d_automount() rather than abusing follow_link() AFS: Use d_automount() rather than abusing follow_link() Add an AT_NO_AUTOMOUNT flag to suppress terminal automount ...
2011-01-15Allow d_manage() to be used in RCU-walk modeDavid Howells1-1/+1
Allow d_manage() to be called from pathwalk when it is in RCU-walk mode as well as when it is in Ref-walk mode. This permits __follow_mount_rcu() to call d_manage() directly. d_manage() needs a parameter to indicate that it is in RCU-walk mode as it isn't allowed to sleep if in that mode (but should return -ECHILD instead). autofs4_d_manage() can then be set to retain RCU-walk mode if the daemon accesses it and otherwise request dropping back to ref-walk mode. Signed-off-by: David Howells <dhowells@redhat.com> Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2011-01-15Add a dentry op to allow processes to be held during pathwalk transitDavid Howells1-0/+2
Add a dentry op (d_manage) to permit a filesystem to hold a process and make it sleep when it tries to transit away from one of that filesystem's directories during a pathwalk. The operation is keyed off a new dentry flag (DCACHE_MANAGE_TRANSIT). The filesystem is allowed to be selective about which processes it holds and which it permits to continue on or prohibits from transiting from each flagged directory. This will allow autofs to hold up client processes whilst letting its userspace daemon through to maintain the directory or the stuff behind it or mounted upon it. The ->d_manage() dentry operation: int (*d_manage)(struct path *path, bool mounting_here); takes a pointer to the directory about to be transited away from and a flag indicating whether the transit is undertaken by do_add_mount() or do_move_mount() skipping through a pile of filesystems mounted on a mountpoint. It should return 0 if successful and to let the process continue on its way; -EISDIR to prohibit the caller from skipping to overmounted filesystems or automounting, and to use this directory; or some other error code to return to the user. ->d_manage() is called with namespace_sem writelocked if mounting_here is true and no other locks held, so it may sleep. However, if mounting_here is true, it may not initiate or wait for a mount or unmount upon the parameter directory, even if the act is actually performed by userspace. Within fs/namei.c, follow_managed() is extended to check with d_manage() first on each managed directory, before transiting away from it or attempting to automount upon it. follow_down() is renamed follow_down_one() and should only be used where the filesystem deliberately intends to avoid management steps (e.g. autofs). A new follow_down() is added that incorporates the loop done by all other callers of follow_down() (do_add/move_mount(), autofs and NFSD; whilst AFS, NFS and CIFS do use it, their use is removed by converting them to use d_automount()). The new follow_down() calls d_manage() as appropriate. It also takes an extra parameter to indicate if it is being called from mount code (with namespace_sem writelocked) which it passes to d_manage(). follow_down() ignores automount points so that it can be used to mount on them. __follow_mount_rcu() is made to abort rcu-walk mode if it hits a directory with DCACHE_MANAGE_TRANSIT set on the basis that we're probably going to have to sleep. It would be possible to enter d_manage() in rcu-walk mode too, and have that determine whether to abort or not itself. That would allow the autofs daemon to continue on in rcu-walk mode. Note that DCACHE_MANAGE_TRANSIT on a directory should be cleared when it isn't required as every tranist from that directory will cause d_manage() to be invoked. It can always be set again when necessary. ========================== WHAT THIS MEANS FOR AUTOFS ========================== Autofs currently uses the lookup() inode op and the d_revalidate() dentry op to trigger the automounting of indirect mounts, and both of these can be called with i_mutex held. autofs knows that the i_mutex will be held by the caller in lookup(), and so can drop it before invoking the daemon - but this isn't so for d_revalidate(), since the lock is only held on _some_ of the code paths that call it. This means that autofs can't risk dropping i_mutex from its d_revalidate() function before it calls the daemon. The bug could manifest itself as, for example, a process that's trying to validate an automount dentry that gets made to wait because that dentry is expired and needs cleaning up: mkdir S ffffffff8014e05a 0 32580 24956 Call Trace: [<ffffffff885371fd>] :autofs4:autofs4_wait+0x674/0x897 [<ffffffff80127f7d>] avc_has_perm+0x46/0x58 [<ffffffff8009fdcf>] autoremove_wake_function+0x0/0x2e [<ffffffff88537be6>] :autofs4:autofs4_expire_wait+0x41/0x6b [<ffffffff88535cfc>] :autofs4:autofs4_revalidate+0x91/0x149 [<ffffffff80036d96>] __lookup_hash+0xa0/0x12f [<ffffffff80057a2f>] lookup_create+0x46/0x80 [<ffffffff800e6e31>] sys_mkdirat+0x56/0xe4 versus the automount daemon which wants to remove that dentry, but can't because the normal process is holding the i_mutex lock: automount D ffffffff8014e05a 0 32581 1 32561 Call Trace: [<ffffffff80063c3f>] __mutex_lock_slowpath+0x60/0x9b [<ffffffff8000ccf1>] do_path_lookup+0x2ca/0x2f1 [<ffffffff80063c89>] .text.lock.mutex+0xf/0x14 [<ffffffff800e6d55>] do_rmdir+0x77/0xde [<ffffffff8005d229>] tracesys+0x71/0xe0 [<ffffffff8005d28d>] tracesys+0xd5/0xe0 which means that the system is deadlocked. This patch allows autofs to hold up normal processes whilst the daemon goes ahead and does things to the dentry tree behind the automouter point without risking a deadlock as almost no locks are held in d_manage() and none in d_automount(). Signed-off-by: David Howells <dhowells@redhat.com> Was-Acked-by: Ian Kent <raven@themaw.net> Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2011-01-15Add a dentry op to handle automounting rather than abusing follow_link()David Howells1-0/+2
Add a dentry op (d_automount) to handle automounting directories rather than abusing the follow_link() inode operation. The operation is keyed off a new dentry flag (DCACHE_NEED_AUTOMOUNT). This also makes it easier to add an AT_ flag to suppress terminal segment automount during pathwalk and removes the need for the kludge code in the pathwalk algorithm to handle directories with follow_link() semantics. The ->d_automount() dentry operation: struct vfsmount *(*d_automount)(struct path *mountpoint); takes a pointer to the directory to be mounted upon, which is expected to provide sufficient data to determine what should be mounted. If successful, it should return the vfsmount struct it creates (which it should also have added to the namespace using do_add_mount() or similar). If there's a collision with another automount attempt, NULL should be returned. If the directory specified by the parameter should be used directly rather than being mounted upon, -EISDIR should be returned. In any other case, an error code should be returned. The ->d_automount() operation is called with no locks held and may sleep. At this point the pathwalk algorithm will be in ref-walk mode. Within fs/namei.c itself, a new pathwalk subroutine (follow_automount()) is added to handle mountpoints. It will return -EREMOTE if the automount flag was set, but no d_automount() op was supplied, -ELOOP if we've encountered too many symlinks or mountpoints, -EISDIR if the walk point should be used without mounting and 0 if successful. The path will be updated to point to the mounted filesystem if a successful automount took place. __follow_mount() is replaced by follow_managed() which is more generic (especially with the patch that adds ->d_manage()). This handles transits from directories during pathwalk, including automounting and skipping over mountpoints (and holding processes with the next patch). __follow_mount_rcu() will jump out of RCU-walk mode if it encounters an automount point with nothing mounted on it. follow_dotdot*() does not handle automounts as you don't want to trigger them whilst following "..". I've also extracted the mount/don't-mount logic from autofs4 and included it here. It makes the mount go ahead anyway if someone calls open() or creat(), tries to traverse the directory, tries to chdir/chroot/etc. into the directory, or sticks a '/' on the end of the pathname. If they do a stat(), however, they'll only trigger the automount if they didn't also say O_NOFOLLOW. I've also added an inode flag (S_AUTOMOUNT) so that filesystems can mark their inodes as automount points. This flag is automatically propagated to the dentry as DCACHE_NEED_AUTOMOUNT by __d_instantiate(). This saves NFS and could save AFS a private flag bit apiece, but is not strictly necessary. It would be preferable to do the propagation in d_set_d_op(), but that doesn't normally have access to the inode. [AV: fixed breakage in case if __follow_mount_rcu() fails and nameidata_drop_rcu() succeeds in RCU case of do_lookup(); we need to fall through to non-RCU case after that, rather than just returning with ungrabbed *path] Signed-off-by: David Howells <dhowells@redhat.com> Was-Acked-by: Ian Kent <raven@themaw.net> Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2011-01-14Merge branch 'for-2.6.38' of git://linux-nfs.org/~bfields/linuxLinus Torvalds1-2/+0
* 'for-2.6.38' of git://linux-nfs.org/~bfields/linux: (62 commits) nfsd4: fix callback restarting nfsd: break lease on unlink, link, and rename nfsd4: break lease on nfsd setattr nfsd: don't support msnfs export option nfsd4: initialize cb_per_client nfsd4: allow restarting callbacks nfsd4: simplify nfsd4_cb_prepare nfsd4: give out delegations more quickly in 4.1 case nfsd4: add helper function to run callbacks nfsd4: make sure sequence flags are set after destroy_session nfsd4: re-probe callback on connection loss nfsd4: set sequence flag when backchannel is down nfsd4: keep finer-grained callback status rpc: allow xprt_class->setup to return a preexisting xprt rpc: keep backchannel xprt as long as server connection rpc: move sk_bc_xprt to svc_xprt nfsd4: allow backchannel recovery nfsd4: support BIND_CONN_TO_SESSION nfsd4: modify session list under cl_lock Documentation: fl_mylease no longer exists ... Fix up conflicts in fs/nfsd/vfs.c with the vfs-scale work. The vfs-scale work touched some msnfs cases, and this merge removes support for that entirely, so the conflict was trivial to resolve.
2011-01-11Documentation: fl_mylease no longer existsJ. Bruce Fields1-2/+0
Signed-off-by: J. Bruce Fields <bfields@redhat.com>
2011-01-07fs: provide rcu-walk aware permission i_opsNick Piggin1-3/+3
Signed-off-by: Nick Piggin <npiggin@kernel.dk>
2011-01-07fs: rcu-walk aware d_revalidate methodNick Piggin1-9/+9
Require filesystems be aware of .d_revalidate being called in rcu-walk mode (nd->flags & LOOKUP_RCU). For now do a simple push down, returning -ECHILD from all implementations. Signed-off-by: Nick Piggin <npiggin@kernel.dk>
2011-01-07fs: dcache remove dcache_lockNick Piggin1-8/+8
dcache_lock no longer protects anything. remove it. Signed-off-by: Nick Piggin <npiggin@kernel.dk>
2011-01-07fs: change d_hash for rcu-walkNick Piggin1-2/+3
Change d_hash so it may be called from lock-free RCU lookups. See similar patch for d_compare for details. For in-tree filesystems, this is just a mechanical change. Signed-off-by: Nick Piggin <npiggin@kernel.dk>
2011-01-07fs: change d_compare for rcu-walkNick Piggin1-1/+3
Change d_compare so it may be called from lock-free RCU lookups. This does put significant restrictions on what may be done from the callback, however there don't seem to have been any problems with in-tree fses. If some strange use case pops up that _really_ cannot cope with the rcu-walk rules, we can just add new rcu-unaware callbacks, which would cause name lookup to drop out of rcu-walk mode. For in-tree filesystems, this is just a mechanical change. Signed-off-by: Nick Piggin <npiggin@kernel.dk>
2011-01-04remove trim_fs method from Documentation/filesystems/LockingChristoph Hellwig1-2/+0
The ->trim_fs has been removed meanwhile, so remove it from the documentation as well. Signed-off-by: Christoph Hellwig <hch@lst.de> Reported-by: Ryusuke Konishi <konishi.ryusuke@lab.ntt.co.jp> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2010-12-30update Documentation/filesystems/LockingChristoph Hellwig1-112/+102
Mostly inspired by all the recent BKL removal changes, but a lot of older updates also weren't properly recorded. Signed-off-by: Christoph Hellwig <hch@lst.de> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2010-12-02Call the filesystem back whenever a page is removed from the page cacheLinus Torvalds1-1/+6
NFS needs to be able to release objects that are stored in the page cache once the page itself is no longer visible from the page cache. This patch adds a callback to the address space operations that allows filesystems to perform page cleanups once the page has been removed from the page cache. Original patch by: Linus Torvalds <torvalds@linux-foundation.org> [trondmy: cover the cases of invalidate_inode_pages2() and truncate_inode_pages()] Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>
2010-10-31locks: remove fl_copy_lock lock_manager operationChristoph Hellwig1-2/+0
This one was only used for a nasty hack in nfsd, which has recently been removed. Signed-off-by: Christoph Hellwig <hch@lst.de> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2010-10-25update block_device_operations documentationChristoph Hellwig1-8/+23
Updated Documentation/filesystems/Locking to match the code. Signed-off-by: Christoph Hellwig <hch@lst.de>
2010-08-14bkl: Remove locked .ioctl file operationArnd Bergmann1-7/+1
The last user is gone, so we can safely remove this Signed-off-by: Arnd Bergmann <arnd@arndb.de> Cc: John Kacur <jkacur@redhat.com> Cc: Al Viro <viro@ZenIV.linux.org.uk> Cc: Thomas Gleixner <tglx@linutronix.de> Signed-off-by: Frederic Weisbecker <fweisbec@gmail.com>
2010-08-09update VFS documentation for method changes.Al Viro1-10/+12
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2010-05-27drop unused dentry argument to ->fsyncChristoph Hellwig1-1/+1
Signed-off-by: Christoph Hellwig <hch@lst.de> Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2010-05-27Documentation/filesystems/Locking: update documentation on llseek() wrt BKLJan Blunck1-2/+3
The inode's i_size is not protected by the big kernel lock. Therefore it does not make sense to recommend taking the BKL in filesystems llseek operations. Instead it should use the inode's mutex or use just use i_size_read() instead. Add a note that this is not protecting file->f_pos. Signed-off-by: Jan Blunck <jblunck@suse.de> Acked-by: Alan Cox <alan@lxorguk.ukuu.org.uk> Cc: Arnd Bergmann <arnd@arndb.de> Cc: Christoph Hellwig <hch@infradead.org> Cc: Frederic Weisbecker <fweisbec@gmail.com> Cc: John Kacur <jkacur@redhat.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2010-05-10doc: inode uses a mutex instead of a semaphore.Thadeu Lima de Souza Cascardo1-2/+2
Replace the introduced i_sem by an i_mutex in the filesystem locking documentation. This was introduced [1] after all occurrences were already replaced in the same text [2]. However, the term "inode semaphore" has not been replaced then, and it's replaced now. [1] afddba49d18f346e5cc2938b6ed7c512db18ca68 [2] a7bc02f4f47fd0e7860c6589f0ad000d1476f7a3 Signed-off-by: Thadeu Lima de Souza Cascardo <cascardo@holoscopio.com> Cc: Nick Piggin <npiggin@suse.de> Cc: Artem Bityutskiy <Artem.Bityutskiy@nokia.com> Cc: Randy Dunlap <rdunlap@xenotime.net> Cc: Christoph Hellwig <hch@lst.de> Cc: Al Viro <viro@zeniv.linux.org.uk> Signed-off-by: Jiri Kosina <jkosina@suse.cz>
2010-03-05dquot: cleanup dquot initialize routineChristoph Hellwig1-2/+0
Get rid of the initialize dquot operation - it is now always called from the filesystem and if a filesystem really needs it's own (which none currently does) it can just call into it's own routine directly. Rename the now static low-level dquot_initialize helper to __dquot_initialize and vfs_dq_init to dquot_initialize to have a consistent namespace. Signed-off-by: Christoph Hellwig <hch@lst.de> Signed-off-by: Jan Kara <jack@suse.cz>
2010-03-05dquot: cleanup dquot drop routineChristoph Hellwig1-2/+0
Get rid of the drop dquot operation - it is now always called from the filesystem and if a filesystem really needs it's own (which none currently does) it can just call into it's own routine directly. Rename the now static low-level dquot_drop helper to __dquot_drop and vfs_dq_drop to dquot_drop to have a consistent namespace. Signed-off-by: Christoph Hellwig <hch@lst.de> Signed-off-by: Jan Kara <jack@suse.cz>
2010-03-05dquot: cleanup dquot transfer routineChristoph Hellwig1-2/+0
Get rid of the transfer dquot operation - it is now always called from the filesystem and if a filesystem really needs it's own (which none currently does) it can just call into it's own routine directly. Rename the now static low-level dquot_transfer helper to __dquot_transfer and vfs_dq_transfer to dquot_transfer to have a consistent namespace, and make the new dquot_transfer return a normal negative errno value which all callers expect. Signed-off-by: Christoph Hellwig <hch@lst.de> Signed-off-by: Jan Kara <jack@suse.cz>
2010-03-05dquot: cleanup inode allocation / freeing routinesChristoph Hellwig1-8/+0
Get rid of the alloc_inode and free_inode dquot operations - they are always called from the filesystem and if a filesystem really needs their own (which none currently does) it can just call into it's own routine directly. Also get rid of the vfs_dq_alloc/vfs_dq_free wrappers and always call the lowlevel dquot_alloc_inode / dqout_free_inode routines directly, which now lose the number argument which is always 1. Signed-off-by: Christoph Hellwig <hch@lst.de> Signed-off-by: Jan Kara <jack@suse.cz>
2010-03-05dquot: cleanup space allocation / freeing routinesChristoph Hellwig1-5/+1
Get rid of the alloc_space, free_space, reserve_space, claim_space and release_rsv dquot operations - they are always called from the filesystem and if a filesystem really needs their own (which none currently does) it can just call into it's own routine directly. Move shared logic into the common __dquot_alloc_space, dquot_claim_space_nodirty and __dquot_free_space low-level methods, and rationalize the wrappers around it to move as much as possible code into the common block for CONFIG_QUOTA vs not. Also rename all these helpers to be named dquot_* instead of vfs_dq_*. Signed-off-by: Christoph Hellwig <hch@lst.de> Signed-off-by: Jan Kara <jack@suse.cz>
2009-06-24update Documentation/filesystems/LockingChristoph Hellwig1-21/+22
The rules for locking in many superblock operations has changed significantly, so update the documentation for it. Also correct some older updates and ommissions. Signed-off-by: Christoph Hellwig <hch@lst.de> Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2009-06-17No instance of ->bmap() needs BKLAl Viro1-1/+1
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2009-05-02mm: close page_mkwrite racesNick Piggin1-8/+16
Change page_mkwrite to allow implementations to return with the page locked, and also change it's callers (in page fault paths) to hold the lock until the page is marked dirty. This allows the filesystem to have full control of page dirtying events coming from the VM. Rather than simply hold the page locked over the page_mkwrite call, we call page_mkwrite with the page unlocked and allow callers to return with it locked, so filesystems can avoid LOR conditions with page lock. The problem with the current scheme is this: a filesystem that wants to associate some metadata with a page as long as the page is dirty, will perform this manipulation in its ->page_mkwrite. It currently then must return with the page unlocked and may not hold any other locks (according to existing page_mkwrite convention). In this window, the VM could write out the page, clearing page-dirty. The filesystem has no good way to detect that a dirty pte is about to be attached, so it will happily write out the page, at which point, the filesystem may manipulate the metadata to reflect that the page is no longer dirty. It is not always possible to perform the required metadata manipulation in ->set_page_dirty, because that function cannot block or fail. The filesystem may need to allocate some data structure, for example. And the VM cannot mark the pte dirty before page_mkwrite, because page_mkwrite is allowed to fail, so we must not allow any window where the page could be written to if page_mkwrite does fail. This solution of holding the page locked over the 3 critical operations (page_mkwrite, setting the pte dirty, and finally setting the page dirty) closes out races nicely, preventing page cleaning for writeout being initiated in that window. This provides the filesystem with a strong synchronisation against the VM here. - Sage needs this race closed for ceph filesystem. - Trond for NFS (http://bugzilla.kernel.org/show_bug.cgi?id=12913). - I need it for fsblock. - I suspect other filesystems may need it too (eg. btrfs). - I have converted buffer.c to the new locking. Even simple block allocation under dirty pages might be susceptible to i_size changing under partial page at the end of file (we also have a buffer.c-side problem here, but it cannot be fixed properly without this patch). - Other filesystems (eg. NFS, maybe btrfs) will need to change their page_mkwrite functions themselves. [ This also moves page_mkwrite another step closer to fault, which should eventually allow page_mkwrite to be moved into ->fault, and thus avoiding a filesystem calldown and page lock/unlock cycle in __do_fault. ] [akpm@linux-foundation.org: fix derefs of NULL ->mapping] Cc: Sage Weil <sage@newdream.net> Cc: Trond Myklebust <trond.myklebust@fys.uio.no> Signed-off-by: Nick Piggin <npiggin@suse.de> Cc: Valdis Kletnieks <Valdis.Kletnieks@vt.edu> Cc: <stable@kernel.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2009-04-01mm: page_mkwrite change prototype to match faultNick Piggin1-1/+1
Change the page_mkwrite prototype to take a struct vm_fault, and return VM_FAULT_xxx flags. There should be no functional change. This makes it possible to return much more detailed error information to the VM (and also can provide more information eg. virtual_address to the driver, which might be important in some special cases). This is required for a subsequent fix. And will also make it easier to merge page_mkwrite() with fault() in future. Signed-off-by: Nick Piggin <npiggin@suse.de> Cc: Chris Mason <chris.mason@oracle.com> Cc: Trond Myklebust <trond.myklebust@fys.uio.no> Cc: Miklos Szeredi <miklos@szeredi.hu> Cc: Steven Whitehouse <swhiteho@redhat.com> Cc: Mark Fasheh <mfasheh@suse.com> Cc: Joel Becker <joel.becker@oracle.com> Cc: Artem Bityutskiy <dedekind@infradead.org> Cc: Felix Blyakher <felixb@sgi.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2009-03-16Move FASYNC bit handling to f_op->fasync()Jonathan Corbet1-2/+5
Removing the BKL from FASYNC handling ran into the challenge of keeping the setting of the FASYNC bit in filp->f_flags atomic with regard to calls to the underlying fasync() function. Andi Kleen suggested moving the handling of that bit into fasync(); this patch does exactly that. As a result, we have a couple of internal API changes: fasync() must now manage the FASYNC bit, and it will be called without the BKL held. As it happens, every fasync() implementation in the kernel with one exception calls fasync_helper(). So, if we make fasync_helper() set the FASYNC bit, we can avoid making any changes to the other fasync() functions - as long as those functions, themselves, have proper locking. Most fasync() implementations do nothing but call fasync_helper() - which has its own lock - so they are easily verified as correct. The BKL had already been pushed down into the rest. The networking code has its own version of fasync_helper(), so that code has been augmented with explicit FASYNC bit handling. Cc: Al Viro <viro@ZenIV.linux.org.uk> Cc: David Miller <davem@davemloft.net> Reviewed-by: Christoph Hellwig <hch@lst.de> Signed-off-by: Jonathan Corbet <corbet@lwn.net>
2009-01-09filesystem freeze: add error handling of write_super_lockfs/unlockfsTakashi Sato1-4/+4
Currently, ext3 in mainline Linux doesn't have the freeze feature which suspends write requests. So, we cannot take a backup which keeps the filesystem's consistency with the storage device's features (snapshot and replication) while it is mounted. In many case, a commercial filesystem (e.g. VxFS) has the freeze feature and it would be used to get the consistent backup. If Linux's standard filesystem ext3 has the freeze feature, we can do it without a commercial filesystem. So I have implemented the ioctls of the freeze feature. I think we can take the consistent backup with the following steps. 1. Freeze the filesystem with the freeze ioctl. 2. Separate the replication volume or create the snapshot with the storage device's feature. 3. Unfreeze the filesystem with the unfreeze ioctl. 4. Take the backup from the separated replication volume or the snapshot. This patch: VFS: Changed the type of write_super_lockfs and unlockfs from "void" to "int" so that they can return an error. Rename write_super_lockfs and unlockfs of the super block operation freeze_fs and unfreeze_fs to avoid a confusion. ext3, ext4, xfs, gfs2, jfs: Changed the type of write_super_lockfs and unlockfs from "void" to "int" so that write_super_lockfs returns an error if needed, and unlockfs always returns 0. reiserfs: Changed the type of write_super_lockfs and unlockfs from "void" to "int" so that they always return 0 (success) to keep a current behavior. Signed-off-by: Takashi Sato <t-sato@yk.jp.nec.com> Signed-off-by: Masayuki Hamaguchi <m-hamaguchi@ys.jp.nec.com> Cc: <xfs-masters@oss.sgi.com> Cc: <linux-ext4@vger.kernel.org> Cc: Christoph Hellwig <hch@lst.de> Cc: Dave Kleikamp <shaggy@austin.ibm.com> Cc: Dave Chinner <david@fromorbit.com> Cc: Alasdair G Kergon <agk@redhat.com> Cc: Al Viro <viro@zeniv.linux.org.uk> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2009-01-06poll: allow f_op->poll to sleepTejun Heo1-1/+1
f_op->poll is the only vfs operation which is not allowed to sleep. It's because poll and select implementation used task state to synchronize against wake ups, which doesn't have to be the case anymore as wait/wake interface can now use custom wake up functions. The non-sleep restriction can be a bit tricky because ->poll is not called from an atomic context and the result of accidentally sleeping in ->poll only shows up as temporary busy looping when the timing is right or rather wrong. This patch converts poll/select to use custom wake up function and use separate triggered variable to synchronize against wake up events. The only added overhead is an extra function call during wake up and negligible. This patch removes the one non-sleep exception from vfs locking rules and is beneficial to userland filesystem implementations like FUSE, 9p or peculiar fs like spufs as it's very difficult for those to implement non-sleeping poll method. While at it, make the following cosmetic changes to make poll.h and select.c checkpatch friendly. * s/type * symbol/type *symbol/ : three places in poll.h * remove blank line before EXPORT_SYMBOL() : two places in select.c Oleg: spotted missing barrier in poll_schedule_timeout() Davide: spotted missing write barrier in pollwake() Signed-off-by: Tejun Heo <tj@kernel.org> Cc: Eric Van Hensbergen <ericvh@gmail.com> Cc: Ron Minnich <rminnich@sandia.gov> Cc: Ingo Molnar <mingo@elte.hu> Cc: Christoph Hellwig <hch@infradead.org> Signed-off-by: Miklos Szeredi <mszeredi@suse.cz> Cc: Davide Libenzi <davidel@xmailserver.org> Cc: Brad Boyer <flar@allandria.com> Cc: Al Viro <viro@zeniv.linux.org.uk> Cc: Roland McGrath <roland@redhat.com> Cc: Mauro Carvalho Chehab <mchehab@infradead.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Cc: Davide Libenzi <davidel@xmailserver.org> Cc: Oleg Nesterov <oleg@redhat.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2008-12-31kill ->dir_notify()Al Viro1-2/+0
Remove the hopelessly misguided ->dir_notify(). The only instance (cifs) has been broken by design from the very beginning; the objects it creates are never destroyed, keep references to struct file they can outlive, nothing that could possibly evict them exists on close(2) path *and* no locking whatsoever is done to prevent races with close(), should the previous, er, deficiencies someday be dealt with. Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2008-10-30fs: remove prepare_write/commit_writeNick Piggin1-5/+7
Nothing uses prepare_write or commit_write. Remove them from the tree completely. [akpm@linux-foundation.org: schedule simple_prepare_write() for unexporting] Signed-off-by: Nick Piggin <npiggin@suse.de> Cc: Christoph Hellwig <hch@lst.de> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2008-09-09update Documentation/filesystems/Locking for 2.6.27 changesChristoph Hellwig1-11/+4
In the 2.6.27 circle ->fasync lost the BKL, and the last remaining ->open variant that takes the BKL is also gone. ->get_sb and ->kill_sb didn't have BKL forever, so updated the entries while we're at that. Signed-off-by: Christoph Hellwig <hch@lst.de> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
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