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2009-12-15task_struct: make journal_info conditionalHiroshi Shimamoto1-0/+1
journal_info in task_struct is used in journaling file system only. So introduce CONFIG_FS_JOURNAL_INFO and make it conditional. Signed-off-by: Hiroshi Shimamoto <h-shimamoto@ct.jp.nec.com> Cc: Chris Mason <chris.mason@oracle.com> Cc: "Theodore Ts'o" <tytso@mit.edu> Cc: Steven Whitehouse <swhiteho@redhat.com> Cc: KONISHI Ryusuke <konishi.ryusuke@lab.ntt.co.jp> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2009-12-09Merge branch 'for-linus' of ↵Linus Torvalds1-1/+1
git://git.kernel.org/pub/scm/linux/kernel/git/jikos/trivial * 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/jikos/trivial: (42 commits) tree-wide: fix misspelling of "definition" in comments reiserfs: fix misspelling of "journaled" doc: Fix a typo in slub.txt. inotify: remove superfluous return code check hdlc: spelling fix in find_pvc() comment doc: fix regulator docs cut-and-pasteism mtd: Fix comment in Kconfig doc: Fix IRQ chip docs tree-wide: fix assorted typos all over the place drivers/ata/libata-sff.c: comment spelling fixes fix typos/grammos in Documentation/edac.txt sysctl: add missing comments fs/debugfs/inode.c: fix comment typos sgivwfb: Make use of ARRAY_SIZE. sky2: fix sky2_link_down copy/paste comment error tree-wide: fix typos "couter" -> "counter" tree-wide: fix typos "offest" -> "offset" fix kerneldoc for set_irq_msi() spidev: fix double "of of" in comment comment typo fix: sybsystem -> subsystem ...
2009-12-09Merge branch 'reiserfs/kill-bkl' of ↵Linus Torvalds16-163/+420
git://git.kernel.org/pub/scm/linux/kernel/git/frederic/random-tracing * 'reiserfs/kill-bkl' of git://git.kernel.org/pub/scm/linux/kernel/git/frederic/random-tracing: (31 commits) kill-the-bkl/reiserfs: turn GFP_ATOMIC flag to GFP_NOFS in reiserfs_get_block() kill-the-bkl/reiserfs: drop the fs race watchdog from _get_block_create_0() kill-the-bkl/reiserfs: definitely drop the bkl from reiserfs_ioctl() kill-the-bkl/reiserfs: always lock the ioctl path kill-the-bkl/reiserfs: fix reiserfs lock to cpu_add_remove_lock dependency kill-the-bkl/reiserfs: Fix induced mm->mmap_sem to sysfs_mutex dependency kill-the-bkl/reiserfs: panic in case of lock imbalance kill-the-bkl/reiserfs: fix recursive reiserfs write lock in reiserfs_commit_write() kill-the-bkl/reiserfs: fix recursive reiserfs lock in reiserfs_mkdir() kill-the-bkl/reiserfs: fix "reiserfs lock" / "inode mutex" lock inversion dependency kill-the-bkl/reiserfs: move the concurrent tree accesses checks per superblock kill-the-bkl/reiserfs: acquire the inode mutex safely kill-the-bkl/reiserfs: unlock only when needed in search_by_key kill-the-bkl/reiserfs: use mutex_lock in reiserfs_mutex_lock_safe kill-the-bkl/reiserfs: factorize the locking in reiserfs_write_end() kill-the-bkl/reiserfs: reduce number of contentions in search_by_key() kill-the-bkl/reiserfs: don't hold the write recursively in reiserfs_lookup() kill-the-bkl/reiserfs: lock only once on reiserfs_get_block() kill-the-bkl/reiserfs: conditionaly release the write lock on fs_changed() kill-the-BKL/reiserfs: add reiserfs_cond_resched() ...
2009-12-04reiserfs: fix misspelling of "journaled"Adam Buchbinder1-1/+1
"Journaled" is misspelled "journlaled" in an output string; this patch fixed it. No changes in functionality. Signed-off-by: Adam Buchbinder <adam.buchbinder@gmail.com> Signed-off-by: Jiri Kosina <jkosina@suse.cz>
2009-11-20kill-the-bkl/reiserfs: turn GFP_ATOMIC flag to GFP_NOFS in reiserfs_get_block()Frederic Weisbecker1-1/+1
GFP_ATOMIC was used in reiserfs_get_block to not lose the Bkl so that nobody can modify the tree in the middle of its work. Now that we kicked out the bkl, we can use a more friendly flag. We use GFP_NOFS here because we already hold the reiserfs lock. Signed-off-by: Frederic Weisbecker <fweisbec@gmail.com> Cc: Jeff Mahoney <jeffm@suse.com> Cc: Chris Mason <chris.mason@oracle.com> Cc: Ingo Molnar <mingo@elte.hu> Cc: Alexander Beregalov <a.beregalov@gmail.com> Cc: Laurent Riffard <laurent.riffard@free.fr> Cc: Thomas Gleixner <tglx@linutronix.de>
2009-10-14kill-the-bkl/reiserfs: drop the fs race watchdog from _get_block_create_0()Frederic Weisbecker1-9/+2
We had a watchdog in _get_block_create_0() that jumped to a fixup retry path in case the bkl got relaxed while calling kmap(). This is not necessary anymore since we now have a reiserfs lock that is not implicitly relaxed while sleeping. Signed-off-by: Frederic Weisbecker <fweisbec@gmail.com> Cc: Jeff Mahoney <jeffm@suse.com> Cc: Chris Mason <chris.mason@oracle.com> Cc: Ingo Molnar <mingo@elte.hu> Cc: Alexander Beregalov <a.beregalov@gmail.com> Cc: Laurent Riffard <laurent.riffard@free.fr> Cc: Thomas Gleixner <tglx@linutronix.de>
2009-10-14kill-the-bkl/reiserfs: definitely drop the bkl from reiserfs_ioctl()Frederic Weisbecker3-10/+5
The reiserfs ioctl path doesn't need the big kernel lock anymore , now that the filesystem synchronizes through its own lock. We can then turn reiserfs_ioctl() into an unlocked_ioctl callback. Signed-off-by: Frederic Weisbecker <fweisbec@gmail.com> Cc: Jeff Mahoney <jeffm@suse.com> Cc: Chris Mason <chris.mason@oracle.com> Cc: Ingo Molnar <mingo@elte.hu> Cc: Alexander Beregalov <a.beregalov@gmail.com> Cc: Laurent Riffard <laurent.riffard@free.fr> Cc: Thomas Gleixner <tglx@linutronix.de>
2009-10-14kill-the-bkl/reiserfs: always lock the ioctl pathFrederic Weisbecker1-27/+39
Reiserfs uses the ioctl callback for its file operations, which means that its ioctl path is still locked by the bkl, this was synchronizing with the rest of the filsystem operations. We have changed that by locking it with the new reiserfs lock but we do that only from the compat_ioctl callback. Fix that by locking reiserfs_ioctl() everytime. Signed-off-by: Frederic Weisbecker <fweisbec@gmail.com> Cc: Jeff Mahoney <jeffm@suse.com> Cc: Chris Mason <chris.mason@oracle.com> Cc: Ingo Molnar <mingo@elte.hu> Cc: Alexander Beregalov <a.beregalov@gmail.com> Cc: Laurent Riffard <laurent.riffard@free.fr> Cc: Thomas Gleixner <tglx@linutronix.de>
2009-10-05kill-the-bkl/reiserfs: fix reiserfs lock to cpu_add_remove_lock dependencyFrederic Weisbecker1-1/+4
While creating the reiserfs workqueue during the journal initialization, we are holding the reiserfs lock, but create_workqueue() also holds the cpu_add_remove_lock, creating then the following dependency: - reiserfs lock -> cpu_add_remove_lock But we also have the following existing dependencies: - mm->mmap_sem -> reiserfs lock - cpu_add_remove_lock -> cpu_hotplug.lock -> slub_lock -> sysfs_mutex The merged dependency chain then becomes: - mm->mmap_sem -> reiserfs lock -> cpu_add_remove_lock -> cpu_hotplug.lock -> slub_lock -> sysfs_mutex But when we fill a dir entry in sysfs_readir(), we are holding the sysfs_mutex and we also might fault while copying the directory entry to the user, leading to the following dependency: - sysfs_mutex -> mm->mmap_sem The end result is then a lock inversion between sysfs_mutex and mm->mmap_sem, as reported in the following lockdep warning: [ INFO: possible circular locking dependency detected ] 2.6.31-07095-g25a3912 #4 ------------------------------------------------------- udevadm/790 is trying to acquire lock: (&mm->mmap_sem){++++++}, at: [<c1098942>] might_fault+0x72/0xc0 but task is already holding lock: (sysfs_mutex){+.+.+.}, at: [<c110813c>] sysfs_readdir+0x7c/0x260 which lock already depends on the new lock. the existing dependency chain (in reverse order) is: -> #5 (sysfs_mutex){+.+.+.}: [...] -> #4 (slub_lock){+++++.}: [...] -> #3 (cpu_hotplug.lock){+.+.+.}: [...] -> #2 (cpu_add_remove_lock){+.+.+.}: [...] -> #1 (&REISERFS_SB(s)->lock){+.+.+.}: [...] -> #0 (&mm->mmap_sem){++++++}: [...] This can be fixed by relaxing the reiserfs lock while creating the workqueue. This is fine to relax the lock here, we just keep it around to pass through reiserfs lock checks and for paranoid reasons. Reported-by: Alexander Beregalov <a.beregalov@gmail.com> Tested-by: Alexander Beregalov <a.beregalov@gmail.com> Signed-off-by: Frederic Weisbecker <fweisbec@gmail.com> Cc: Jeff Mahoney <jeffm@suse.com> Cc: Chris Mason <chris.mason@oracle.com> Cc: Ingo Molnar <mingo@elte.hu> Cc: Alexander Beregalov <a.beregalov@gmail.com> Cc: Laurent Riffard <laurent.riffard@free.fr>
2009-09-22const: make struct super_block::s_qcop constAlexey Dobriyan1-1/+1
Signed-off-by: Alexey Dobriyan <adobriyan@gmail.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2009-09-22const: make struct super_block::dq_op constAlexey Dobriyan1-1/+1
Signed-off-by: Alexey Dobriyan <adobriyan@gmail.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2009-09-17kill-the-bkl/reiserfs: Fix induced mm->mmap_sem to sysfs_mutex dependencyFrederic Weisbecker1-0/+16
Alexander Beregalov reported the following warning: ======================================================= [ INFO: possible circular locking dependency detected ] 2.6.31-03149-gdcc030a #1 ------------------------------------------------------- udevadm/716 is trying to acquire lock: (&mm->mmap_sem){++++++}, at: [<c107249a>] might_fault+0x4a/0xa0 but task is already holding lock: (sysfs_mutex){+.+.+.}, at: [<c10cb9aa>] sysfs_readdir+0x5a/0x200 which lock already depends on the new lock. the existing dependency chain (in reverse order) is: -> #3 (sysfs_mutex){+.+.+.}: [...] -> #2 (&bdev->bd_mutex){+.+.+.}: [...] -> #1 (&REISERFS_SB(s)->lock){+.+.+.}: [...] -> #0 (&mm->mmap_sem){++++++}: [...] On reiserfs mount path, we take the reiserfs lock and while initializing the journal, we open the device, taking the bdev->bd_mutex. Then rescan_partition() may signal the change to sysfs. We have then the following dependency: reiserfs_lock -> bd_mutex -> sysfs_mutex Later, while entering reiserfs_readpage() after a pagefault in an mmaped reiserfs file, we are holding the mm->mmap_sem, and we are going to take the reiserfs lock too. We have then the following dependency: mm->mmap_sem -> reiserfs_lock which, expanded with the previous dependency gives us: mm->mmap_sem -> reiserfs_lock -> bd_mutex -> sysfs_mutex Now while entering the sysfs readdir path, we are holding the sysfs_mutex. And when we copy a directory entry to the user buffer, we might fault and then take the mm->mmap_sem lock. Which leads to the circular locking dependency reported. We can fix that by relaxing the reiserfs lock during the call to journal_init_dev(), which is the place where we open the mounted device. This is fine to relax the lock here because we are in the begining of the reiserfs mount path and there is nothing to protect at this time, the journal is not intialized. We just keep this lock around for paranoid reasons. Reported-by: Alexander Beregalov <a.beregalov@gmail.com> Tested-by: Alexander Beregalov <a.beregalov@gmail.com> Signed-off-by: Frederic Weisbecker <fweisbec@gmail.com> Cc: Jeff Mahoney <jeffm@suse.com> Cc: Chris Mason <chris.mason@oracle.com> Cc: Ingo Molnar <mingo@elte.hu> Cc: Alexander Beregalov <a.beregalov@gmail.com> Cc: Laurent Riffard <laurent.riffard@free.fr>
2009-09-14kill-the-bkl/reiserfs: panic in case of lock imbalanceFrederic Weisbecker1-4/+3
Until now, trying to unlock the reiserfs write lock whereas the current task doesn't hold it lead to a simple warning. We should actually warn and panic in this case to avoid the user datas to reach an unstable state. Signed-off-by: Frederic Weisbecker <fweisbec@gmail.com> Cc: Jeff Mahoney <jeffm@suse.com> Cc: Chris Mason <chris.mason@oracle.com> Cc: Ingo Molnar <mingo@elte.hu> Cc: Alexander Beregalov <a.beregalov@gmail.com> Cc: Laurent Riffard <laurent.riffard@free.fr>
2009-09-14kill-the-bkl/reiserfs: fix recursive reiserfs write lock in ↵Frederic Weisbecker1-9/+2
reiserfs_commit_write() reiserfs_commit_write() is always called with the write lock held. Thus the current calls to reiserfs_write_lock() in this function are acquiring the lock recursively. We can safely drop them. This also solves further assumptions for this lock to be really released while calling reiserfs_write_unlock(). Signed-off-by: Frederic Weisbecker <fweisbec@gmail.com> Cc: Jeff Mahoney <jeffm@suse.com> Cc: Chris Mason <chris.mason@oracle.com> Cc: Ingo Molnar <mingo@elte.hu> Cc: Alexander Beregalov <a.beregalov@gmail.com> Cc: Laurent Riffard <laurent.riffard@free.fr>
2009-09-14kill-the-bkl/reiserfs: fix recursive reiserfs lock in reiserfs_mkdir()Frederic Weisbecker1-3/+4
reiserfs_mkdir() acquires the reiserfs lock, assuming it has been called from the dir inodes callbacks, without the lock held. But it can also be called from other internal sites such as reiserfs_xattr_init() which already holds the lock. This recursive locking leads to further wrong assumptions. For example, later calls to reiserfs_mutex_lock_safe() won't actually unlock the reiserfs lock the time we acquire a given mutex, creating unexpected lock inversions. Signed-off-by: Frederic Weisbecker <fweisbec@gmail.com> Cc: Jeff Mahoney <jeffm@suse.com> Cc: Chris Mason <chris.mason@oracle.com> Cc: Ingo Molnar <mingo@elte.hu> Cc: Alexander Beregalov <a.beregalov@gmail.com> Cc: Laurent Riffard <laurent.riffard@free.fr>
2009-09-14kill-the-bkl/reiserfs: fix "reiserfs lock" / "inode mutex" lock inversion ↵Frederic Weisbecker1-1/+1
dependency reiserfs_xattr_init is called with the reiserfs write lock held, but if the ".reiserfs_priv" entry is not created, we take the superblock root directory inode mutex until .reiserfs_priv is created. This creates a lock dependency inversion against other sites such as reiserfs_file_release() which takes an inode mutex and the reiserfs lock after. Signed-off-by: Frederic Weisbecker <fweisbec@gmail.com> Cc: Jeff Mahoney <jeffm@suse.com> Cc: Chris Mason <chris.mason@oracle.com> Cc: Ingo Molnar <mingo@elte.hu> Cc: Alexander Beregalov <a.beregalov@gmail.com> Cc: Laurent Riffard <laurent.riffard@free.fr>
2009-09-14kill-the-bkl/reiserfs: move the concurrent tree accesses checks per superblockFrederic Weisbecker4-24/+7
When do_balance() balances the tree, a trick is performed to provide the ability for other tree writers/readers to check whether do_balance() is executing concurrently (requires CONFIG_REISERFS_CHECK). This is done to protect concurrent accesses to the tree. The trick is the following: When do_balance is called, a unique global variable called cur_tb takes a pointer to the current tree to be rebalanced. Once do_balance finishes its work, cur_tb takes the NULL value. Then, concurrent tree readers/writers just have to check the value of cur_tb to ensure do_balance isn't executing concurrently. If it is, then it proves that schedule() occured on do_balance(), which then relaxed the bkl that protected the tree. Now that the bkl has be turned into a mutex, this check is still fine even though do_balance() becomes preemptible: the write lock will not be automatically released on schedule(), so the tree is still protected. But this is only fine if we have a single reiserfs mountpoint. Indeed, because the bkl is a global lock, it didn't allowed concurrent executions between a tree reader/writer in a mount point and a do_balance() on another tree from another mountpoint. So assuming all these readers/writers weren't supposed to be reentrant, the current check now sometimes detect false positives with the current per-superblock mutex which allows this reentrancy. This patch keeps the concurrent tree accesses check but moves it per superblock, so that only trees from a same mount point are checked to be not accessed concurrently. [ Impact: fix spurious panic while running several reiserfs mount-points ] Cc: Jeff Mahoney <jeffm@suse.com> Cc: Chris Mason <chris.mason@oracle.com> Cc: Ingo Molnar <mingo@elte.hu> Cc: Alexander Beregalov <a.beregalov@gmail.com> Signed-off-by: Frederic Weisbecker <fweisbec@gmail.com>
2009-09-14kill-the-bkl/reiserfs: acquire the inode mutex safelyFrederic Weisbecker2-36/+2
While searching a pathname, an inode mutex can be acquired in do_lookup() which calls reiserfs_lookup() which in turn acquires the write lock. On the other side reiserfs_fill_super() can acquire the write_lock and then call reiserfs_lookup_privroot() which can acquire an inode mutex (the root of the mount point). So we theoretically risk an AB - BA lock inversion that could lead to a deadlock. As for other lock dependencies found since the bkl to mutex conversion, the fix is to use reiserfs_mutex_lock_safe() which drops the lock dependency to the write lock. [ Impact: fix a possible deadlock with reiserfs ] Cc: Jeff Mahoney <jeffm@suse.com> Cc: Chris Mason <chris.mason@oracle.com> Cc: Ingo Molnar <mingo@elte.hu> Cc: Alexander Beregalov <a.beregalov@gmail.com> Signed-off-by: Frederic Weisbecker <fweisbec@gmail.com>
2009-09-14kill-the-bkl/reiserfs: unlock only when needed in search_by_keyFrederic Weisbecker1-8/+34
search_by_key() is the site which most requires the lock. This is mostly because it is a very central function and also because it releases/reaqcuires the write lock at least once each time it is called. Such release/reacquire creates a lot of contention in this place and also opens more the window which let another thread changing the tree. When it happens, the current path searching over the tree must be retried from the beggining (the root) which is a wasteful and time consuming recovery. This patch factorizes two release/reacquire sequences: - reading leaf nodes blocks - reading current block The latter immediately follows the former. The whole sequence is safe as a single unlocked section because we check just after if the tree has changed during these operations. Cc: Jeff Mahoney <jeffm@suse.com> Cc: Chris Mason <chris.mason@oracle.com> Cc: Ingo Molnar <mingo@elte.hu> Cc: Alexander Beregalov <a.beregalov@gmail.com> Signed-off-by: Frederic Weisbecker <fweisbec@gmail.com>
2009-09-14kill-the-bkl/reiserfs: use mutex_lock in reiserfs_mutex_lock_safeFrederic Weisbecker1-5/+3
reiserfs_mutex_lock_safe() is a hack to avoid any dependency between an internal reiserfs mutex and the write lock, it has been proposed to follow the old bkl logic. The code does the following: while (!mutex_trylock(m)) { reiserfs_write_unlock(s); schedule(); reiserfs_write_lock(s); } It then imitate the implicit behaviour of the lock when it was a Bkl and hadn't such dependency: mutex_lock(m) { if (fastpath) let's go else { wait_for_mutex() { schedule() { unlock_kernel() reacquire_lock_kernel() } } } } The problem is that by using such explicit schedule(), we don't benefit of the adaptive mutex spinning on owner. The logic in use now is: reiserfs_write_unlock(s); mutex_lock(m); // -> possible adaptive spinning reiserfs_write_lock(s); [ Impact: restore the use of adaptive spinning mutexes in reiserfs ] Cc: Jeff Mahoney <jeffm@suse.com> Cc: Chris Mason <chris.mason@oracle.com> Cc: Ingo Molnar <mingo@elte.hu> Cc: Alexander Beregalov <a.beregalov@gmail.com> Signed-off-by: Frederic Weisbecker <fweisbec@gmail.com>
2009-09-14kill-the-bkl/reiserfs: factorize the locking in reiserfs_write_end()Frederic Weisbecker1-10/+15
reiserfs_write_end() is a hot path in reiserfs. We have two wasteful write lock lock/release inside that can be gathered without changing the code logic. This patch factorizes them out in a single protected section, reducing the number of contentions inside. [ Impact: reduce lock contention in a reiserfs hotpath ] Cc: Jeff Mahoney <jeffm@suse.com> Cc: Chris Mason <chris.mason@oracle.com> Cc: Ingo Molnar <mingo@elte.hu> Cc: Alexander Beregalov <a.beregalov@gmail.com> Signed-off-by: Frederic Weisbecker <fweisbec@gmail.com>
2009-09-14kill-the-bkl/reiserfs: reduce number of contentions in search_by_key()Frederic Weisbecker1-1/+11
search_by_key() is a central function in reiserfs which searches the patch in the fs tree from the root to a node given its key. It is the function that is most requesting the write lock because it's a path very often used. Also we forget to release the lock while reading the next tree node, making us holding the lock in a wasteful way. Then we release the lock while reading the current node and its childs, all-in-one. It should be safe because we have a reference to these blocks and even if we read a block that will be concurrently changed, we have an fs_changed check later that will make us retry the path from the root. [ Impact: release the write lock while unused in a hot path ] Cc: Jeff Mahoney <jeffm@suse.com> Cc: Chris Mason <chris.mason@oracle.com> Cc: Ingo Molnar <mingo@elte.hu> Cc: Alexander Beregalov <a.beregalov@gmail.com> Signed-off-by: Frederic Weisbecker <fweisbec@gmail.com>
2009-09-14kill-the-bkl/reiserfs: don't hold the write recursively in reiserfs_lookup()Frederic Weisbecker1-3/+10
The write lock can be acquired recursively in reiserfs_lookup(). But we may want to *really* release the lock before possible rescheduling from a reiserfs_lookup() callee. Hence we want to only acquire the lock once (ie: not recursively). [ Impact: prevent from possible false unreleased write lock on sleeping ] Cc: Jeff Mahoney <jeffm@suse.com> Cc: Chris Mason <chris.mason@oracle.com> Cc: Ingo Molnar <mingo@elte.hu> Cc: Alexander Beregalov <a.beregalov@gmail.com> Signed-off-by: Frederic Weisbecker <fweisbec@gmail.com>
2009-09-14kill-the-bkl/reiserfs: lock only once on reiserfs_get_block()Frederic Weisbecker1-8/+11
reiserfs_get_block() is one of these sites where the write lock might be acquired recursively. It's a particular problem because this function is called very often. It's a hot spot which needs to reschedule() periodically while converting direct items to indirect ones because it can take some time. Then if we are applying the write lock release/reacquire pattern on schedule() here, it may not produce the desired effect since we may have locked in more than one depth. The solution is to use reiserfs_write_lock_once() which won't try to reacquire the lock recursively. Then the lock will be *really* released before schedule(). Also, we only release the lock if TIF_NEED_RESCHED is set to not create wasteful numerous contentions. [ Impact: fix a too long holded lock case in reiserfs_get_block() ] Cc: Jeff Mahoney <jeffm@suse.com> Cc: Chris Mason <chris.mason@oracle.com> Cc: Ingo Molnar <mingo@elte.hu> Cc: Alexander Beregalov <a.beregalov@gmail.com> Signed-off-by: Frederic Weisbecker <fweisbec@gmail.com>
2009-09-14kill-the-BKL/reiserfs: release the write lock on flush_commit_list()Frederic Weisbecker1-2/+5
flush_commit_list() uses ll_rw_block() to commit the pending log blocks. ll_rw_block() might sleep, and the bkl was released at this point. Then we can also relax the write lock at this point. [ Impact: release the reiserfs write lock when it is not needed ] Cc: Jeff Mahoney <jeffm@suse.com> Cc: Chris Mason <chris.mason@oracle.com> Cc: Alexander Beregalov <a.beregalov@gmail.com> Signed-off-by: Frederic Weisbecker <fweisbec@gmail.com>
2009-09-14kill-the-BKL/reiserfs: release the write lock inside ↵Frederic Weisbecker1-0/+2
reiserfs_read_bitmap_block() reiserfs_read_bitmap_block() uses sb_bread() to read the bitmap block. This helper might sleep. Then, when the bkl was used, it was released at this point. We can then relax the write lock too here. [ Impact: release the reiserfs write lock when it is not needed ] Cc: Jeff Mahoney <jeffm@suse.com> Cc: Chris Mason <chris.mason@oracle.com> Cc: Alexander Beregalov <a.beregalov@gmail.com> Signed-off-by: Frederic Weisbecker <fweisbec@gmail.com>
2009-09-14kill-the-BKL/reiserfs: release the write lock inside get_neighbors()Frederic Weisbecker1-0/+4
get_neighbors() is used to get the left and/or right blocks against a given one in order to balance a tree. sb_bread() is used to read the buffer of these neighors blocks and while it waits for this operation, it might sleep. The bkl was released at this point, and then we can also release the write lock before calling sb_bread(). This is safe because if the filesystem is changed after this lock release, the function returns REPEAT_SEARCH (aka SCHEDULE_OCCURRED in the function header comments) in order to repeat the neighbhor research. [ Impact: release the reiserfs write lock when it is not needed ] Cc: Jeff Mahoney <jeffm@suse.com> Cc: Chris Mason <chris.mason@oracle.com> Cc: Alexander Beregalov <a.beregalov@gmail.com> Signed-off-by: Frederic Weisbecker <fweisbec@gmail.com>
2009-09-14kill-the-BKL/reiserfs: release write lock while rescheduling on ↵Frederic Weisbecker1-0/+2
prepare_for_delete_or_cut() prepare_for_delete_or_cut() can process several types of items, including indirect items, ie: items which contain no file data but pointers to unformatted nodes scattering the datas of a file. In this case it has to zero out these pointers to block numbers of unformatted nodes and release the bitmap from these block numbers. It can take some time, so a rescheduling() is performed between each block processed. We can safely release the write lock while rescheduling(), like the bkl did, because the code checks just after if the item has moved after sleeping. [ Impact: release the reiserfs write lock when it is not needed ] Cc: Jeff Mahoney <jeffm@suse.com> Cc: Chris Mason <chris.mason@oracle.com> Cc: Alexander Beregalov <a.beregalov@gmail.com> Signed-off-by: Frederic Weisbecker <fweisbec@gmail.com>
2009-09-14kill-the-BKL/reiserfs: release the write lock before rescheduling on ↵Frederic Weisbecker1-0/+2
do_journal_end() When do_journal_end() copies data to the journal blocks buffers in memory, it reschedules if needed between each block copied and dirtyfied. We can also release the write lock at this rescheduling stage, like did the bkl implicitly. [ Impact: release the reiserfs write lock when it is not needed ] Cc: Jeff Mahoney <jeffm@suse.com> Cc: Chris Mason <chris.mason@oracle.com> Cc: Alexander Beregalov <a.beregalov@gmail.com> Signed-off-by: Frederic Weisbecker <fweisbec@gmail.com>
2009-09-14kill-the-BKL/reiserfs: only acquire the write lock once in reiserfs_dirty_inodeFrederic Weisbecker1-6/+9
Impact: fix a deadlock reiserfs_dirty_inode() is the super_operations::dirty_inode() callback of reiserfs. It can be called from different contexts where the write lock can be already held. But this function also grab the write lock (possibly recursively). Subsequent release of the lock before sleep will actually not release the lock if the caller of mark_inode_dirty() (which in turn calls reiserfs_dirty_inode()) already owns the lock. A typical case: reiserfs_write_end() { acquire_write_lock() mark_inode_dirty() { reiserfs_dirty_inode() { reacquire_write_lock() { journal_begin() { do_journal_begin_r() { /* * fail to release, still * one depth of lock */ release_write_lock() reiserfs_wait_on_write_block() { wait_event() The event is usually provided by something which needs the write lock but it hasn't been released. We use reiserfs_write_lock_once() here to ensure we only grab the write lock in one level. Signed-off-by: Frederic Weisbecker <fweisbec@gmail.com> Cc: Frederic Weisbecker <fweisbec@gmail.com> Cc: Alessio Igor Bogani <abogani@texware.it> Cc: Jeff Mahoney <jeffm@suse.com> Cc: Chris Mason <chris.mason@oracle.com> LKML-Reference: <1239680065-25013-4-git-send-email-fweisbec@gmail.com> Signed-off-by: Ingo Molnar <mingo@elte.hu>
2009-09-14kill-the-BKL/reiserfs: lock only once in reiserfs_truncate_fileFrederic Weisbecker1-3/+7
Impact: fix a deadlock reiserfs_truncate_file() can be called from multiple context where the write lock can be already hold or not. This function also acquire (possibly recursively) the write lock. Subsequent releases before sleeping will not actually release the lock because we may be in more than one lock depth degree. A typical case is: reiserfs_file_release { acquire_the_lock() reiserfs_truncate_file() reacquire_the_lock() journal_begin() { do_journal_begin_r() { reiserfs_wait_on_write_block() { /* * Not released because still one * depth owned */ release_lock() wait_for_event() At this stage the event never happen because the one which provides it needs the write lock. We use reiserfs_write_lock_once() here to ensure that we don't acquire the write lock recursively. Signed-off-by: Frederic Weisbecker <fweisbec@gmail.com> Cc: Alessio Igor Bogani <abogani@texware.it> Cc: Jeff Mahoney <jeffm@suse.com> Cc: Alexander Beregalov <a.beregalov@gmail.com> Cc: Chris Mason <chris.mason@oracle.com> LKML-Reference: <1239680065-25013-3-git-send-email-fweisbec@gmail.com> Signed-off-by: Ingo Molnar <mingo@elte.hu>
2009-09-14kill-the-BKL/reiserfs: provide a tool to lock only once the write lockFrederic Weisbecker1-0/+26
Sometimes we don't want to recursively hold the per superblock write lock because we want to be sure it is actually released when we come to sleep. This patch introduces the necessary tools for that. reiserfs_write_lock_once() does the same job than reiserfs_write_lock() except that it won't try to acquire recursively the lock if the current task already owns it. Also the lock_depth before the call of this function is returned. reiserfs_write_unlock_once() unlock only if reiserfs_write_lock_once() returned a depth equal to -1, ie: only if it actually locked. Signed-off-by: Frederic Weisbecker <fweisbec@gmail.com> Cc: Alessio Igor Bogani <abogani@texware.it> Cc: Jeff Mahoney <jeffm@suse.com> Cc: Alexander Beregalov <a.beregalov@gmail.com> Cc: Chris Mason <chris.mason@oracle.com> LKML-Reference: <1239680065-25013-2-git-send-email-fweisbec@gmail.com> Signed-off-by: Ingo Molnar <mingo@elte.hu>
2009-09-14reiserfs, kill-the-BKL: fix unsafe j_flush_mutex lockFrederic Weisbecker1-1/+1
Impact: fix a deadlock The j_flush_mutex is acquired safely in journal.c: if we can't take it, we free the reiserfs per superblock lock and wait a bit. But we have a remaining place in kupdate_transactions() where j_flush_mutex is still acquired traditionnaly. Thus the following scenario (warned by lockdep) can happen: A B mutex_lock(&write_lock) mutex_lock(&write_lock) mutex_lock(&j_flush_mutex) mutex_lock(&j_flush_mutex) //block mutex_unlock(&write_lock) sleep... mutex_lock(&write_lock) //deadlock Fix this by using reiserfs_mutex_lock_safe() in kupdate_transactions(). Signed-off-by: Frederic Weisbecker <fweisbec@gmail.com> Cc: Alessio Igor Bogani <abogani@texware.it> Cc: Jeff Mahoney <jeffm@suse.com> LKML-Reference: <1239660635-12940-1-git-send-email-fweisbec@gmail.com> Signed-off-by: Ingo Molnar <mingo@elte.hu>
2009-09-14reiserfs: kill-the-BKLFrederic Weisbecker11-44/+245
This patch is an attempt to remove the Bkl based locking scheme from reiserfs and is intended. It is a bit inspired from an old attempt by Peter Zijlstra: http://lkml.indiana.edu/hypermail/linux/kernel/0704.2/2174.html The bkl is heavily used in this filesystem to prevent from concurrent write accesses on the filesystem. Reiserfs makes a deep use of the specific properties of the Bkl: - It can be acqquired recursively by a same task - It is released on the schedule() calls and reacquired when schedule() returns The two properties above are a roadmap for the reiserfs write locking so it's very hard to simply replace it with a common mutex. - We need a recursive-able locking unless we want to restructure several blocks of the code. - We need to identify the sites where the bkl was implictly relaxed (schedule, wait, sync, etc...) so that we can in turn release and reacquire our new lock explicitly. Such implicit releases of the lock are often required to let other resources producer/consumer do their job or we can suffer unexpected starvations or deadlocks. So the new lock that replaces the bkl here is a per superblock mutex with a specific property: it can be acquired recursively by a same task, like the bkl. For such purpose, we integrate a lock owner and a lock depth field on the superblock information structure. The first axis on this patch is to turn reiserfs_write_(un)lock() function into a wrapper to manage this mutex. Also some explicit calls to lock_kernel() have been converted to reiserfs_write_lock() helpers. The second axis is to find the important blocking sites (schedule...(), wait_on_buffer(), sync_dirty_buffer(), etc...) and then apply an explicit release of the write lock on these locations before blocking. Then we can safely wait for those who can give us resources or those who need some. Typically this is a fight between the current writer, the reiserfs workqueue (aka the async commiter) and the pdflush threads. The third axis is a consequence of the second. The write lock is usually on top of a lock dependency chain which can include the journal lock, the flush lock or the commit lock. So it's dangerous to release and trying to reacquire the write lock while we still hold other locks. This is fine with the bkl: T1 T2 lock_kernel() mutex_lock(A) unlock_kernel() // do something lock_kernel() mutex_lock(A) -> already locked by T1 schedule() (and then unlock_kernel()) lock_kernel() mutex_unlock(A) .... This is not fine with a mutex: T1 T2 mutex_lock(write) mutex_lock(A) mutex_unlock(write) // do something mutex_lock(write) mutex_lock(A) -> already locked by T1 schedule() mutex_lock(write) -> already locked by T2 deadlock The solution in this patch is to provide a helper which releases the write lock and sleep a bit if we can't lock a mutex that depend on it. It's another simulation of the bkl behaviour. The last axis is to locate the fs callbacks that are called with the bkl held, according to Documentation/filesystem/Locking. Those are: - reiserfs_remount - reiserfs_fill_super - reiserfs_put_super Reiserfs didn't need to explicitly lock because of the context of these callbacks. But now we must take care of that with the new locking. After this patch, reiserfs suffers from a slight performance regression (for now). On UP, a high volume write with dd reports an average of 27 MB/s instead of 30 MB/s without the patch applied. Signed-off-by: Frederic Weisbecker <fweisbec@gmail.com> Reviewed-by: Ingo Molnar <mingo@elte.hu> Cc: Jeff Mahoney <jeffm@suse.com> Cc: Peter Zijlstra <a.p.zijlstra@chello.nl> Cc: Bron Gondwana <brong@fastmail.fm> Cc: Andrew Morton <akpm@linux-foundation.org> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Alexander Viro <viro@zeniv.linux.org.uk> LKML-Reference: <1239070789-13354-1-git-send-email-fweisbec@gmail.com> Signed-off-by: Ingo Molnar <mingo@elte.hu>
2009-07-12headers: smp_lock.h reduxAlexey Dobriyan1-1/+0
* Remove smp_lock.h from files which don't need it (including some headers!) * Add smp_lock.h to files which do need it * Make smp_lock.h include conditional in hardirq.h It's needed only for one kernel_locked() usage which is under CONFIG_PREEMPT This will make hardirq.h inclusion cheaper for every PREEMPT=n config (which includes allmodconfig/allyesconfig, BTW) Signed-off-by: Alexey Dobriyan <adobriyan@gmail.com> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2009-07-10Fix congestion_wait() sync/async vs read/write confusionJens Axboe1-1/+1
Commit 1faa16d22877f4839bd433547d770c676d1d964c accidentally broke the bdi congestion wait queue logic, causing us to wait on congestion for WRITE (== 1) when we really wanted BLK_RW_ASYNC (== 0) instead. Signed-off-by: Jens Axboe <jens.axboe@oracle.com>
2009-07-08headers: mnt_namespace.h reduxAlexey Dobriyan1-1/+0
Fix various silly problems wrt mnt_namespace.h: - exit_mnt_ns() isn't used, remove it - done that, sched.h and nsproxy.h inclusions aren't needed - mount.h inclusion was need for vfsmount_lock, but no longer - remove mnt_namespace.h inclusion from files which don't use anything from mnt_namespace.h Signed-off-by: Alexey Dobriyan <adobriyan@gmail.com> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2009-06-24helpers for acl caching + switch to thoseAl Viro1-39/+10
helpers: get_cached_acl(inode, type), set_cached_acl(inode, type, acl), forget_cached_acl(inode, type). ubifs/xattr.c needed includes reordered, the rest is a plain switchover. Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2009-06-24switch reiserfs to inode->i_aclAl Viro3-34/+4
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2009-06-24switch reiserfs to usual conventions for caching ACLsAl Viro2-19/+14
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2009-06-24reiserfs: minimal fix for ACL cachingAl Viro1-1/+1
reiserfs uses NULL as "unknown" and ERR_PTR(-ENODATA) as "no ACL"; several codepaths store the former instead of the latter. All those codepaths go through iset_acl() and all cases when it's called with NULL acl are for the second variety, so the minimal fix is to teach iset_acl() to deal with that. Proper fix is to switch to more usual conventions and avoid back and forth between internally used ERR_PTR(-ENODATA) and NULL expected by the rest of the kernel. Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2009-06-24reiserfs: remove stray unlock_super in reiserfs_resizeChristoph Hellwig1-1/+0
Reiserfs doesn't use lock_super anywhere internally, and ->remount_fs which calls reiserfs_resize does have it currently but also expects it to be held on return, so there's no business for the unlock_super here. Signed-off-by: Christoph Hellwig <hch@lst.de> Acked by Edward Shishkin <edward.shishkin@gmail.com> Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2009-06-18reiserfs: fix warnings with gcc 4.4Jeff Mahoney2-7/+8
Several code paths in reiserfs have a construct like: if (is_direntry_le_ih(ih = B_N_PITEM_HEAD(src, item_num))) ... which, in addition to being ugly, end up causing compiler warnings with gcc 4.4.0. Previous compilers didn't issue a warning. fs/reiserfs/do_balan.c:1273: warning: operation on `aux_ih' may be undefined fs/reiserfs/lbalance.c:393: warning: operation on `ih' may be undefined fs/reiserfs/lbalance.c:421: warning: operation on `ih' may be undefined fs/reiserfs/lbalance.c:777: warning: operation on `ih' may be undefined I believe this is due to the ih being passed to macros which evaluate the argument more than once. This is old code and we haven't seen any problems with it, but this patch eliminates the warnings. It converts the multiple evaluation macros to static inlines and does a preassignment for the cases that were causing the warnings because that code is just ugly. Reported-by: Chris Mason <mason@oracle.com> Signed-off-by: Jeff Mahoney <jeffm@suse.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2009-06-11Push BKL down into ->remount_fs()Alessio Igor Bogani1-0/+4
[xfs, btrfs, capifs, shmem don't need BKL, exempt] Signed-off-by: Alessio Igor Bogani <abogani@texware.it> Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2009-06-11push BKL down into ->put_superChristoph Hellwig1-1/+3
Move BKL into ->put_super from the only caller. A couple of filesystems had trivial enough ->put_super (only kfree and NULLing of s_fs_info + stuff in there) to not get any locking: coda, cramfs, efs, hugetlbfs, omfs, qnx4, shmem, all others got the full treatment. Most of them probably don't need it, but I'd rather sort that out individually. Preferably after all the other BKL pushdowns in that area. [AV: original used to move lock_super() down as well; these changes are removed since we don't do lock_super() at all in generic_shutdown_super() now] [AV: fuse, btrfs and xfs are known to need no damn BKL, exempt] Signed-off-by: Christoph Hellwig <hch@lst.de> Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2009-06-11enforce ->sync_fs is only called for rw superblockChristoph Hellwig1-12/+9
Make sure a superblock really is writeable by checking MS_RDONLY under s_umount. sync_filesystems needed some re-arragement for that, but all but one sync_filesystem caller had the correct locking already so that we could add that check there. cachefiles grew s_umount locking. I've also added a WARN_ON to sync_filesystem to assert this for future callers. Signed-off-by: Christoph Hellwig <hch@lst.de> Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2009-06-11remove ->write_super call in generic_shutdown_superChristoph Hellwig1-0/+3
We just did a full fs writeout using sync_filesystem before, and if that's not enough for the filesystem it can perform it's own writeout in ->put_super, which many filesystems already do. Move a call to foofs_write_super into every foofs_put_super for now to guarantee identical behaviour until it's cleaned up by the individual filesystem maintainers. Exceptions: - affs already has identical copy & pasted code at the beginning of affs_put_super so no need to do it twice. - xfs does the right thing without it and I have changes pending for the xfs tree touching this are so I don't really need conflicts here.. Signed-off-by: Christoph Hellwig <hch@lst.de> Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2009-06-11reiserfs: allow exposing privroot w/ xattrs enabledJeff Mahoney3-7/+7
This patch adds an -oexpose_privroot option to allow access to the privroot. Signed-off-by: Jeff Mahoney <jeffm@suse.com> Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2009-05-17reiserfs: fixup perms when xattrs are disabledJeff Mahoney1-17/+19
This adds CONFIG_REISERFS_FS_XATTR protection from reiserfs_permission. This is needed to avoid warnings during file deletions and chowns with xattrs disabled. Signed-off-by: Jeff Mahoney <jeffm@suse.com> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2009-05-17reiserfs: deal with NULL xattr root w/ xattrs disabledJeff Mahoney2-3/+3
This avoids an Oops in open_xa_root that can occur when deleting a file with xattrs disabled. It assumes that the xattr root will be there, and that is not guaranteed. Signed-off-by: Jeff Mahoney <jeffm@suse.com> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>