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* VFS: delay the dentry name generation on sockets and pipesEric Dumazet2007-05-081-0/+31
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | 1) Introduces a new method in 'struct dentry_operations'. This method called d_dname() might be called from d_path() to build a pathname for special filesystems. It is called without locks. Future patches (if we succeed in having one common dentry for all pipes/sockets) may need to change prototype of this method, but we now use : char *d_dname(struct dentry *dentry, char *buffer, int buflen); 2) Adds a dynamic_dname() helper function that eases d_dname() implementations 3) Defines d_dname method for sockets : No more sprintf() at socket creation. This is delayed up to the moment someone does an access to /proc/pid/fd/... 4) Defines d_dname method for pipes : No more sprintf() at pipe creation. This is delayed up to the moment someone does an access to /proc/pid/fd/... A benchmark consisting of 1.000.000 calls to pipe()/close()/close() gives a *nice* speedup on my Pentium(M) 1.6 Ghz : 3.090 s instead of 3.450 s Signed-off-by: Eric Dumazet <dada1@cosmosbay.com> Acked-by: Christoph Hellwig <hch@infradead.org> Acked-by: Linus Torvalds <torvalds@linux-foundation.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* mm: shrink parent dentries when shrinking slabAndrew Morton2007-05-081-1/+1
| | | | | | | | | | | | | | | | Teach the dentry slab shrinker to aggressively shrink parent dentries when shrinking the dentry cache. This is done to attempt to improve the situation where the dentry slab cache gets a lot of internal fragmentation due to pages containing directory dentries. It is expected that this change will cause some of those dentries to be reaped earlier, and with less scanning. Needs careful testing. Cc: Miklos Szeredi <mszeredi@suse.cz> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* fix quadratic behavior of shrink_dcache_parent()Miklos Szeredi2007-05-081-37/+67
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | The time shrink_dcache_parent() takes, grows quadratically with the depth of the tree under 'parent'. This starts to get noticable at about 10,000. These kinds of depths don't occur normally, and filesystems which invoke shrink_dcache_parent() via d_invalidate() seem to have other depth dependent timings, so it's not even easy to expose this problem. However with FUSE it's easy to create a deep tree and d_invalidate() will also get called. This can make a syscall hang for a very long time. This is the original discovery of the problem by Russ Cox: http://article.gmane.org/gmane.comp.file-systems.fuse.devel/3826 The following patch fixes the quadratic behavior, by optionally allowing prune_dcache() to prune ancestors of a dentry in one go, instead of doing it one at a time. Common code in dput() and prune_one_dentry() is extracted into a new helper function d_kill(). shrink_dcache_parent() as well as shrink_dcache_sb() are converted to use the ancestry-pruner option. Only for shrink_dcache_memory() is this behavior not desirable, so it keeps using the old algorithm. Signed-off-by: Miklos Szeredi <mszeredi@suse.cz> Cc: Al Viro <viro@zeniv.linux.org.uk> Cc: Maneesh Soni <maneesh@in.ibm.com> Acked-by: "Paul E. McKenney" <paulmck@us.ibm.com> Cc: Dipankar Sarma <dipankar@in.ibm.com> Cc: Neil Brown <neilb@suse.de> Cc: Trond Myklebust <trond.myklebust@fys.uio.no> Cc: Christoph Hellwig <hch@lst.de> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* KMEM_CACHE(): simplify slab cache creationChristoph Lameter2007-05-071-6/+2
| | | | | | | | | | | | | | | | | | | | | | | | | | | This patch provides a new macro KMEM_CACHE(<struct>, <flags>) to simplify slab creation. KMEM_CACHE creates a slab with the name of the struct, with the size of the struct and with the alignment of the struct. Additional slab flags may be specified if necessary. Example struct test_slab { int a,b,c; struct list_head; } __cacheline_aligned_in_smp; test_slab_cache = KMEM_CACHE(test_slab, SLAB_PANIC) will create a new slab named "test_slab" of the size sizeof(struct test_slab) and aligned to the alignment of test slab. If it fails then we panic. Signed-off-by: Christoph Lameter <clameter@sgi.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* Revert "[PATCH] Fix d_path for lazy unmounts"Linus Torvalds2007-02-131-80/+70
| | | | | | | | | | | | | | | | | This reverts commit eb3dfb0cb1f4a44e2d0553f89514ce9f2a9fcaf1. It causes some strange Gnome problem with dbus-daemon getting stuck, so we'll revert it until that problem is understood. Reported by both walt and Greg KH, who both independently git-bisected the problem to this commit. Andreas is looking at it. Reported-by: walt <wa1ter@myrealbox.com> Reported-by: Greg KH <greg@kroah.com> Acked-by: Andreas Gruenbacher <agruen@suse.de> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* [PATCH] Fix d_path for lazy unmountsAndreas Gruenbacher2007-02-121-70/+80
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Here is a bugfix to d_path. First, when d_path() hits a lazily unmounted mount point, it tries to prepend the name of the lazily unmounted dentry to the path name. It gets this wrong, and also overwrites the slash that separates the name from the following pathname component. This is demonstrated by the attached test case, which prints "getcwd returned d_path-bugsubdir" with the bug. The correct result would be "getcwd returned d_path-bug/subdir". It could be argued that the name of the root dentry should not be part of the result of d_path in the first place. On the other hand, what the unconnected namespace was once reachable as may provide some useful hints to users, and so that seems okay. Second, it isn't always possible to tell from the __d_path result whether the specified root and rootmnt (i.e., the chroot) was reached: lazy unmounts of bind mounts will produce a path that does start with a non-slash so we can tell from that, but other lazy unmounts will produce a path that starts with a slash, just like "ordinary" paths. The attached patch cleans up __d_path() to fix the bug with overlapping pathname components. It also adds a @fail_deleted argument, which allows to get rid of some of the mess in sys_getcwd(). Grabbing the dcache_lock can then also be moved into __d_path(). The patch also makes sure that paths will only start with a slash for paths which are connected to the root and rootmnt. The @fail_deleted argument could be added to d_path() as well: this would allow callers to recognize deleted files, without having to resort to the ambiguous check for the " (deleted)" string at the end of the pathnames. This is not currently done, but it might be worthwhile. Signed-off-by: Andreas Gruenbacher <agruen@suse.de> Cc: Neil Brown <neilb@suse.de> Cc: Al Viro <viro@zeniv.linux.org.uk> Cc: Christoph Hellwig <hch@lst.de> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* [PATCH] dcache: avoid RCU for never-hashed dentriesEric Dumazet2006-12-071-4/+12
| | | | | | | | | | | | | | | | | | | | | | Some dentries don't need to be globally visible in dentry hashtable. (pipes & sockets) Such dentries dont need to wait for a RCU grace period at delete time. Being able to free them permits a better CPU cache use (hot cache) This patch combined with (dont insert pipe dentries into dentry_hashtable) reduced time of { pipe(p); close(p[0]); close(p[1]);} on my UP machine (1.6 GHz Pentium-M) from 3.23 us to 2.86 us (But this patch does not depend on other patches, only bench results) Signed-off-by: Eric Dumazet <dada1@cosmosbay.com> Cc: Al Viro <viro@zeniv.linux.org.uk> Cc: Maneesh Soni <maneesh@in.ibm.com> Cc: "Paul E. McKenney" <paulmck@us.ibm.com> Cc: Dipankar Sarma <dipankar@in.ibm.com> Acked-by: David Miller <davem@davemloft.net> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
* [PATCH] slab: remove kmem_cache_tChristoph Lameter2006-12-071-3/+3
| | | | | | | | | | | | | | | | | | | | | | | | | | | | Replace all uses of kmem_cache_t with struct kmem_cache. The patch was generated using the following script: #!/bin/sh # # Replace one string by another in all the kernel sources. # set -e for file in `find * -name "*.c" -o -name "*.h"|xargs grep -l $1`; do quilt add $file sed -e "1,\$s/$1/$2/g" $file >/tmp/$$ mv /tmp/$$ $file quilt refresh done The script was run like this sh replace kmem_cache_t "struct kmem_cache" Signed-off-by: Christoph Lameter <clameter@sgi.com> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
* [PATCH] VFS: Fix an error in unused dentry countingDavid Howells2006-10-281-2/+8
| | | | | | | | | | | | | With Vasily Averin <vvs@sw.ru> Fix an error in unused dentry counting in shrink_dcache_for_umount_subtree() in which the count is modified without the dcache_lock held. Signed-off-by: David Howells <dhowells@redhat.com> Cc: Vasily Averin <vvs@sw.ru> Cc: Neil Brown <neilb@suse.de> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
* [PATCH] missing unused dentry in prune_dcache()?Vasily Averin2006-10-281-4/+5
| | | | | | | | | | | | | | | | | | | | | | | | | | | | On the the following patch: http://linux.bkbits.net:8080/linux-2.6/gnupatch@449b144ecSF1rYskg3q-SeR2vf88zg # ChangeSet # 2006/06/22 15:05:57-07:00 neilb@suse.de # [PATCH] Fix dcache race during umount # If prune_dcache finds a dentry that it cannot free, it leaves it where it # is (at the tail of the list) and exits, on the assumption that some other # thread will be removing that dentry soon. However as far as I see this comment is not correct: when we cannot take s_umount rw_semaphore (for example because it was taken in do_remount) this dentry is already extracted from dentry_unused list and we do not add it into the list again. Therefore dentry will not be found by prune_dcache() and shrink_dcache_sb() and will leave in memory very long time until the partition will be unmounted. The patch adds this dentry into tail of the dentry_unused list. Signed-off-by: Vasily Averin <vvs@sw.ru> Cc: Neil Brown <neilb@suse.de> Acked-by: David Howells <dhowells@redhat.com> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
* [PATCH] VFS: Make d_materialise_unique() enforce directory uniquenessTrond Myklebust2006-10-211-37/+100
| | | | | | | | | | | | | | | | | | | | | If the caller tries to instantiate a directory using an inode that already has a dentry alias, then we attempt to rename the existing dentry instead of instantiating a new one. Fail with an ELOOP error if the rename would affect one of our parent directories. This behaviour is needed in order to avoid issues such as http://bugzilla.kernel.org/show_bug.cgi?id=7178 Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com> Cc: Miklos Szeredi <miklos@szeredi.hu> Cc: Maneesh Soni <maneesh@in.ibm.com> Cc: Dipankar Sarma <dipankar@in.ibm.com> Cc: Neil Brown <neilb@cse.unsw.edu.au> Cc: Al Viro <viro@zeniv.linux.org.uk> Cc: Christoph Hellwig <hch@lst.de> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
* [PATCH] VFS: Destroy the dentries contributed by a superblock on unmountingDavid Howells2006-10-111-0/+130
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | The attached patch destroys all the dentries attached to a superblock in one go by: (1) Destroying the tree rooted at s_root. (2) Destroying every entry in the anon list, one at a time. (3) Each entry in the anon list has its subtree consumed from the leaves inwards. This reduces the amount of work generic_shutdown_super() does, and avoids iterating through the dentry_unused list. Note that locking is almost entirely absent in the shrink_dcache_for_umount*() functions added by this patch. This is because: (1) at the point the filesystem calls generic_shutdown_super(), it is not permitted to further touch the superblock's set of dentries, and nor may it remove aliases from inodes; (2) the dcache memory shrinker now skips dentries that are being unmounted; and (3) the superblock no longer has any external references through which the VFS can reach it. Given these points, the only locking we need to do is when we remove dentries from the unused list and the name hashes, which we do a directory's worth at a time. We also don't need to guard against reference counts going to zero unexpectedly and removing bits of the tree we're working on as nothing else can call dput(). A cut down version of dentry_iput() has been folded into shrink_dcache_for_umount_subtree() function. Apart from not needing to unlock things, it also doesn't need to check for inotify watches. In this version of the patch, the complaint about a dentry still being in use has been expanded from a single BUG_ON() and now gives much more information. Signed-off-by: David Howells <dhowells@redhat.com> Acked-by: NeilBrown <neilb@suse.de> Acked-by: Ian Kent <raven@themaw.net> Cc: Trond Myklebust <trond.myklebust@fys.uio.no> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
* [PATCH] knfsd: close a race-opportunity in d_splice_aliasNeilBrown2006-10-041-4/+5
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | There is a possible race in d_splice_alias. Though __d_find_alias(inode, 1) will only return a dentry with DCACHE_DISCONNECTED set, it is possible for it to get cleared before the BUG_ON, and it is is not possible to lock against that. There are a couple of problems here. Firstly, the code doesn't match the comment. The comment describes a 'disconnected' dentry as being IS_ROOT as well as DCACHE_DISCONNECTED, however there is not testing of IS_ROOT anythere. A dentry is marked DCACHE_DISCONNECTED when allocated with d_alloc_anon, and remains DCACHE_DISCONNECTED while a path is built up towards the root. So a dentry can have a valid name and a valid parent and even grandparent, but will still be DCACHE_DISCONNECTED until a path to the root is created. Once the path to the root is complete, everything in the path gets DCACHE_DISCONNECTED cleared. So the fact that DCACHE_DISCONNECTED isn't enough to say that a dentry is free to be spliced in with a given name. This can only be allowed if the dentry does not yet have a name, so the IS_ROOT test is needed too. However even adding that test to __d_find_alias isn't enough. As d_splice_alias drops dcache_lock before calling d_move to perform the splice, it could race with another thread calling d_splice_alias to splice the inode in with a different name in a different part of the tree (in the case where a file has hard links). So that splicing code is only really safe for directories (as we know that directories only have one link). For directories, the caller of d_splice_alias will be holding i_mutex on the (unique) parent so there is no room for a race. A consequence of this is that a non-directory will never benefit from being spliced into a pre-exisiting dentry, but that isn't a problem. It is perfectly OK for a non-directory to have multiple dentries, some anonymous, some not. And the comment for d_splice_alias says that it only happens for directories anyway. Signed-off-by: Neil Brown <neilb@suse.de> Cc: Christoph Hellwig <hch@lst.de> Cc: Al Viro <viro@zeniv.linux.org.uk> Cc: Dipankar Sarma <dipankar@in.ibm.com> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
* [PATCH] BLOCK: Move extern declarations out of fs/*.c into header files [try #6]David Howells2006-09-301-3/+1
| | | | | | | | | | | Create a new header file, fs/internal.h, for common definitions local to the sources in the fs/ directory. Move extern definitions that should be in header files from fs/*.c to fs/internal.h or other main header files where they span directories. Signed-Off-By: David Howells <dhowells@redhat.com> Signed-off-by: Jens Axboe <axboe@kernel.dk>
* NFS: Add dentry materialisation opDavid Howells2006-09-221-14/+150
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | The attached patch adds a new directory cache management function that prepares a disconnected anonymous function to be connected into the dentry tree. The anonymous dentry is transferred the name and parentage from another dentry. The following changes were made in [try #2]: (*) d_materialise_dentry() now switches the parentage of the two nodes around correctly when one or other of them is self-referential. The following changes were made in [try #7]: (*) d_instantiate_unique() has had the interior part split out as function __d_instantiate_unique(). Callers of this latter function must be holding the appropriate locks. (*) _d_rehash() has been added as a wrapper around __d_rehash() to call it with the most obvious hash list (the one from the name). d_rehash() now calls _d_rehash(). (*) d_materialise_dentry() is now __d_materialise_dentry() and is static. (*) d_materialise_unique() added to perform the combination of d_find_alias(), d_materialise_dentry() and d_add_unique() that the NFS client was doing twice, all within a single dcache_lock critical section. This reduces the number of times two different spinlocks were being accessed. The following further changes were made: (*) Add the dentries onto their parents d_subdirs lists. Signed-Off-By: David Howells <dhowells@redhat.com> Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>
* [PATCH] lockdep: annotate dcacheIngo Molnar2006-07-031-2/+2
| | | | | | | | | | Teach special (recursive) locking code to the lock validator. Has no effect on non-lockdep kernels. Signed-off-by: Ingo Molnar <mingo@elte.hu> Signed-off-by: Arjan van de Ven <arjan@linux.intel.com> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
* [PATCH] lockdep: locking init debugging improvementIngo Molnar2006-07-031-1/+1
| | | | | | | | | | | | Locking init improvement: - introduce and use __SPIN_LOCK_UNLOCKED for array initializations, to pass in the name string of locks, used by debugging Signed-off-by: Ingo Molnar <mingo@elte.hu> Signed-off-by: Arjan van de Ven <arjan@linux.intel.com> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
* Remove obsolete #include <linux/config.h>Jörn Engel2006-06-301-1/+0
| | | | | Signed-off-by: Jörn Engel <joern@wohnheim.fh-wedel.de> Signed-off-by: Adrian Bunk <bunk@stusta.de>
* [PATCH] core: use list_move()Akinobu Mita2006-06-261-2/+1
| | | | | | | | | | | This patch converts the combination of list_del(A) and list_add(A, B) to list_move(A, B). Cc: Greg Kroah-Hartman <gregkh@suse.de> Cc: Ram Pai <linuxram@us.ibm.com> Signed-off-by: Akinobu Mita <mita@miraclelinux.com> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
* [PATCH] use list_add_tail() instead of list_add()Akinobu Mita2006-06-261-1/+1
| | | | | | | | | | | | | | This patch converts list_add(A, B.prev) to list_add_tail(A, &B) for readability. Acked-by: Karsten Keil <kkeil@suse.de> Cc: Jan Harkes <jaharkes@cs.cmu.edu> Acked-by: Jan Kara <jack@suse.cz> AOLed-by: David Woodhouse <dwmw2@infradead.org> Cc: Sridhar Samudrala <sri@us.ibm.com> Signed-off-by: Akinobu Mita <mita@miraclelinux.com> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
* [PATCH] remove unlikely(sb) in prune_dcacheHua Zhong2006-06-251-1/+1
| | | | | | | | | | | | | | | | | likely profiling shows that the following is a miss. After boot: [+- ] Type | # True | # False | Function:Filename@Line +unlikely | 1074| 0 prune_dcache()@:fs/dcache.c@409 After a bonnie++ run: +unlikely | 66716| 19584 prune_dcache()@:fs/dcache.c@409 So remove it. Signed-off-by: Hua Zhong <hzhong@gmail.com> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
* [PATCH] VFS: Permit filesystem to override root dentry on mountDavid Howells2006-06-231-40/+0
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Extend the get_sb() filesystem operation to take an extra argument that permits the VFS to pass in the target vfsmount that defines the mountpoint. The filesystem is then required to manually set the superblock and root dentry pointers. For most filesystems, this should be done with simple_set_mnt() which will set the superblock pointer and then set the root dentry to the superblock's s_root (as per the old default behaviour). The get_sb() op now returns an integer as there's now no need to return the superblock pointer. This patch permits a superblock to be implicitly shared amongst several mount points, such as can be done with NFS to avoid potential inode aliasing. In such a case, simple_set_mnt() would not be called, and instead the mnt_root and mnt_sb would be set directly. The patch also makes the following changes: (*) the get_sb_*() convenience functions in the core kernel now take a vfsmount pointer argument and return an integer, so most filesystems have to change very little. (*) If one of the convenience function is not used, then get_sb() should normally call simple_set_mnt() to instantiate the vfsmount. This will always return 0, and so can be tail-called from get_sb(). (*) generic_shutdown_super() now calls shrink_dcache_sb() to clean up the dcache upon superblock destruction rather than shrink_dcache_anon(). This is required because the superblock may now have multiple trees that aren't actually bound to s_root, but that still need to be cleaned up. The currently called functions assume that the whole tree is rooted at s_root, and that anonymous dentries are not the roots of trees which results in dentries being left unculled. However, with the way NFS superblock sharing are currently set to be implemented, these assumptions are violated: the root of the filesystem is simply a dummy dentry and inode (the real inode for '/' may well be inaccessible), and all the vfsmounts are rooted on anonymous[*] dentries with child trees. [*] Anonymous until discovered from another tree. (*) The documentation has been adjusted, including the additional bit of changing ext2_* into foo_* in the documentation. [akpm@osdl.org: convert ipath_fs, do other stuff] Signed-off-by: David Howells <dhowells@redhat.com> Acked-by: Al Viro <viro@zeniv.linux.org.uk> Cc: Nathan Scott <nathans@sgi.com> Cc: Roland Dreier <rolandd@cisco.com> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
* [PATCH] prune_one_dentry() tweaksAndrew Morton2006-06-221-4/+5
| | | | | | | | | | | | | | - Add description of d_lock handling to comments over prune_one_dentry(). - It has three callsites - uninline it, saving 200 bytes of text. Cc: Jan Blunck <jblunck@suse.de> Cc: Kirill Korotaev <dev@openvz.org> Cc: Olaf Hering <olh@suse.de> Cc: Balbir Singh <balbir@in.ibm.com> Cc: Neil Brown <neilb@suse.de> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
* [PATCH] Fix dcache race during umountNeilBrown2006-06-221-6/+60
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | The race is that the shrink_dcache_memory shrinker could get called while a filesystem is being unmounted, and could try to prune a dentry belonging to that filesystem. If it does, then it will call in to iput on the inode while the dentry is no longer able to be found by the umounting process. If iput takes a while, generic_shutdown_super could get all the way though shrink_dcache_parent and shrink_dcache_anon and invalidate_inodes without ever waiting on this particular inode. Eventually the superblock gets freed anyway and if the iput tried to touch it (which some filesystems certainly do), it will lose. The promised "Self-destruct in 5 seconds" doesn't lead to a nice day. The race is closed by holding s_umount while calling prune_one_dentry on someone else's dentry. As a down_read_trylock is used, shrink_dcache_memory will no longer try to prune the dentry of a filesystem that is being unmounted, and unmount will not be able to start until any such active prune_one_dentry completes. This requires that prune_dcache *knows* which filesystem (if any) it is doing the prune on behalf of so that it can be careful of other filesystems. shrink_dcache_memory isn't called it on behalf of any filesystem, and so is careful of everything. shrink_dcache_anon is now passed a super_block rather than the s_anon list out of the superblock, so it can get the s_anon list itself, and can pass the superblock down to prune_dcache. If prune_dcache finds a dentry that it cannot free, it leaves it where it is (at the tail of the list) and exits, on the assumption that some other thread will be removing that dentry soon. To try to make sure that some work gets done, a limited number of dnetries which are untouchable are skipped over while choosing the dentry to work on. I believe this race was first found by Kirill Korotaev. Cc: Jan Blunck <jblunck@suse.de> Acked-by: Kirill Korotaev <dev@openvz.org> Cc: Olaf Hering <olh@suse.de> Acked-by: Balbir Singh <balbir@in.ibm.com> Signed-off-by: Neil Brown <neilb@suse.de> Signed-off-by: Balbir Singh <balbir@in.ibm.com> Acked-by: David Howells <dhowells@redhat.com> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
* [PATCH] dcache: Add helper d_hash_and_lookupEric W. Biederman2006-03-311-16/+28
| | | | | | | | | | | It is very common to hash a dentry and then to call lookup. If we take fs specific hash functions into account the full hash logic can get ugly. Further full_name_hash as an inline function is almost 100 bytes on x86 so having a non-inline choice in some cases can measurably decrease code size. Signed-off-by: Eric W. Biederman <ebiederm@xmission.com> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
* [PATCH] inotify: IN_DELETE events missingAmy Griffis2006-03-311-3/+3
| | | | | | | | | | | | | | | | | | | IN_DELETE events are no longer generated for the removal of a file from a watched directory. This seems to be a result of clearing DCACHE_INOTIFY_PARENT_WATCHED in d_delete() directly before calling fsnotify_nameremove(). Assuming the flag doesn't need to be cleared before dentry_iput(), this should do the trick. Signed-off-by: Amy Griffis <amy.griffis@hp.com> Cc: John McCutchan <ttb@tentacle.dhs.org> Acked-by: Robert Love <rml@novell.com> Cc: Nick Piggin <nickpiggin@yahoo.com.au> Cc: <stable@kernel.org> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
* Merge git://git.kernel.org/pub/scm/linux/kernel/git/bunk/trivialLinus Torvalds2006-03-261-10/+1
|\ | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | * git://git.kernel.org/pub/scm/linux/kernel/git/bunk/trivial: drivers/char/ftape/lowlevel/fdc-io.c: Correct a comment Kconfig help: MTD_JEDECPROBE already supports Intel Remove ugly debugging stuff do_mounts.c: Minor ROOT_DEV comment cleanup BUG_ON() Conversion in drivers/s390/block/dasd_devmap.c BUG_ON() Conversion in mm/mempool.c BUG_ON() Conversion in mm/memory.c BUG_ON() Conversion in kernel/fork.c BUG_ON() Conversion in ipc/sem.c BUG_ON() Conversion in fs/ext2/ BUG_ON() Conversion in fs/hfs/ BUG_ON() Conversion in fs/dcache.c BUG_ON() Conversion in fs/buffer.c BUG_ON() Conversion in input/serio/hp_sdc_mlc.c BUG_ON() Conversion in md/dm-table.c BUG_ON() Conversion in md/dm-path-selector.c BUG_ON() Conversion in drivers/isdn BUG_ON() Conversion in drivers/char BUG_ON() Conversion in drivers/mtd/
| * Remove ugly debugging stuffArtem B. Bityuckiy2006-03-261-9/+0
| | | | | | | | Signed-off-by: Adrian Bunk <bunk@stusta.de>
| * BUG_ON() Conversion in fs/dcache.cEric Sesterhenn2006-03-261-1/+1
| | | | | | | | | | | | | | | | this changes if() BUG(); constructs to BUG_ON() which is cleaner and can better optimized away Signed-off-by: Eric Sesterhenn <snakebyte@gmx.de> Signed-off-by: Adrian Bunk <bunk@stusta.de>
* | [PATCH] Use __read_mostly on some hot fs variablesEric Dumazet2006-03-261-7/+7
|/ | | | | | | | | | | | | | I discovered on oprofile hunting on a SMP platform that dentry lookups were slowed down because d_hash_mask, d_hash_shift and dentry_hashtable were in a cache line that contained inodes_stat. So each time inodes_stats is changed by a cpu, other cpus have to refill their cache line. This patch moves some variables to the __read_mostly section, in order to avoid false sharing. RCU dentry lookups can go full speed. Signed-off-by: Eric Dumazet <dada1@cosmosbay.com> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
* [PATCH] Reduce sched latency in shrink_dcache_sb()Kirill Korotaev2006-03-251-0/+1
| | | | | | | | | | | | This patch reduces scheduling latency in shrink_dcache_sb() noticed during remounting of big partitions with many cached dentries. The same latency fix was applied to select_parent() long ago. Signed-off-by: Denis Lunev <den@sw.ru> Signed-off-by: Pavel Emelianov <xemul@sw.ru> Signed-off-by: Kirill Korotaev <dev@openvz.org> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
* [PATCH] inotify: lock avoidance with parent watch status in dentryNick Piggin2006-03-251-0/+8
| | | | | | | | | | | | | | | | | | | | | | Previous inotify work avoidance is good when inotify is completely unused, but it breaks down if even a single watch is in place anywhere in the system. Robin Holt notices that udev is one such culprit - it slows down a 512-thread application on a 512 CPU system from 6 seconds to 22 minutes. Solve this by adding a flag in the dentry that tells inotify whether or not its parent inode has a watch on it. Event queueing to parent will skip taking locks if this flag is cleared. Setting and clearing of this flag on all child dentries versus event delivery: this is no in terms of race cases, and that was shown to be equivalent to always performing the check. The essential behaviour is that activity occuring _after_ a watch has been added and _before_ it has been removed, will generate events. Signed-off-by: Nick Piggin <npiggin@suse.de> Cc: Robert Love <rml@novell.com> Cc: John McCutchan <ttb@tentacle.dhs.org> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
* [PATCH] Optimise d_find_alias()David Howells2006-03-251-4/+7
| | | | | | | | | | | | | | | | | | | The attached patch optimises d_find_alias() to only take the spinlock if there's anything in the the inode's alias list. If there isn't, it returns NULL immediately. With respect to the superblock sharing patch, this should reduce by one the number of times the dcache_lock is taken by nfs_lookup() for ordinary directory lookups. Only in the case where there's already a dentry for particular directory inode (such as might happen when another mountpoint is rooted at that dentry) will the lock then be taken the extra time. Signed-off-by: David Howells <dhowells@redhat.com> Cc: Trond Myklebust <trond.myklebust@fys.uio.no> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
* [PATCH] cpuset memory spread slab cache hooksPaul Jackson2006-03-241-1/+2
| | | | | | | | | | | | | | | | | | Change the kmem_cache_create calls for certain slab caches to support cpuset memory spreading. See the previous patches, cpuset_mem_spread, for an explanation of cpuset memory spreading, and cpuset_mem_spread_slab_cache for the slab cache support for memory spreading. The slab caches marked for now are: dentry_cache, inode_cache, some xfs slab caches, and buffer_head. This list may change over time. In particular, other file system types that are used extensively on large NUMA systems may want to allow for spreading their directory and inode slab cache entries. Signed-off-by: Paul Jackson <pj@sgi.com> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
* [PATCH] fix file countingDipankar Sarma2006-03-081-1/+1
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | I have benchmarked this on an x86_64 NUMA system and see no significant performance difference on kernbench. Tested on both x86_64 and powerpc. The way we do file struct accounting is not very suitable for batched freeing. For scalability reasons, file accounting was constructor/destructor based. This meant that nr_files was decremented only when the object was removed from the slab cache. This is susceptible to slab fragmentation. With RCU based file structure, consequent batched freeing and a test program like Serge's, we just speed this up and end up with a very fragmented slab - llm22:~ # cat /proc/sys/fs/file-nr 587730 0 758844 At the same time, I see only a 2000+ objects in filp cache. The following patch I fixes this problem. This patch changes the file counting by removing the filp_count_lock. Instead we use a separate percpu counter, nr_files, for now and all accesses to it are through get_nr_files() api. In the sysctl handler for nr_files, we populate files_stat.nr_files before returning to user. Counting files as an when they are created and destroyed (as opposed to inside slab) allows us to correctly count open files with RCU. Signed-off-by: Dipankar Sarma <dipankar@in.ibm.com> Cc: "Paul E. McKenney" <paulmck@us.ibm.com> Cc: "David S. Miller" <davem@davemloft.net> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
* [PATCH] make "struct d_cookie" depend on CONFIG_PROFILINGMarcelo Tosatti2006-02-031-0/+2
| | | | | | | | | | Shrinks "struct dentry" from 128 bytes to 124 on x86, allowing 31 objects per slab instead of 30. Cc: John Levon <levon@movementarian.org> Cc: Philippe Elie <phil.el@wanadoo.fr> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
* [PATCH] Unlinline a bunch of other functionsArjan van de Ven2006-01-141-1/+1
| | | | | | | | | | | Remove the "inline" keyword from a bunch of big functions in the kernel with the goal of shrinking it by 30kb to 40kb Signed-off-by: Arjan van de Ven <arjan@infradead.org> Signed-off-by: Ingo Molnar <mingo@elte.hu> Acked-by: Jeff Garzik <jgarzik@pobox.com> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
* [PATCH] d_instantiate_unique / NFS inode leakageOleg Drokin2006-01-101-1/+6
| | | | | | | | | | | | If we have found aliased dentry that we return, inode reference is not dropped and inode is not attached anywhere, so it seems the reference to inode is leaked in that case. Cc: Trond Myklebust <trond.myklebust@fys.uio.no>, Cc: <viro@parcelfarce.linux.theplanet.co.uk> Cc: Christoph Hellwig <hch@lst.de> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
* [PATCH] shrink dentry structEric Dumazet2006-01-081-17/+17
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Some long time ago, dentry struct was carefully tuned so that on 32 bits UP, sizeof(struct dentry) was exactly 128, ie a power of 2, and a multiple of memory cache lines. Then RCU was added and dentry struct enlarged by two pointers, with nice results for SMP, but not so good on UP, because breaking the above tuning (128 + 8 = 136 bytes) This patch reverts this unwanted side effect, by using an union (d_u), where d_rcu and d_child are placed so that these two fields can share their memory needs. At the time d_free() is called (and d_rcu is really used), d_child is known to be empty and not touched by the dentry freeing. Lockless lookups only access d_name, d_parent, d_lock, d_op, d_flags (so the previous content of d_child is not needed if said dentry was unhashed but still accessed by a CPU because of RCU constraints) As dentry cache easily contains millions of entries, a size reduction is worth the extra complexity of the ugly C union. Signed-off-by: Eric Dumazet <dada1@cosmosbay.com> Cc: Dipankar Sarma <dipankar@in.ibm.com> Cc: Maneesh Soni <maneesh@in.ibm.com> Cc: Miklos Szeredi <miklos@szeredi.hu> Cc: "Paul E. McKenney" <paulmck@us.ibm.com> Cc: Ian Kent <raven@themaw.net> Cc: Paul Jackson <pj@sgi.com> Cc: Al Viro <viro@ftp.linux.org.uk> Cc: Christoph Hellwig <hch@lst.de> Cc: Trond Myklebust <trond.myklebust@fys.uio.no> Cc: Neil Brown <neilb@cse.unsw.edu.au> Cc: James Morris <jmorris@namei.org> Cc: Stephen Smalley <sds@epoch.ncsc.mil> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
* [PATCH] Remove hlist_for_each_rcu() API, convert existing use to ↵Paul E. McKenney2005-11-071-6/+4
| | | | | | | | | | | | | hlist_for_each_entry_rcu Remove the hlist_for_each_rcu() API, which is used only in one place, and is trivially converted to hlist_for_each_entry_rcu(), making the code shorter and more readable. Any out-of-tree uses may be similarly converted. Signed-off-by: "Paul E. McKenney" <paulmck@us.ibm.com> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
* [PATCH] gfp_t: fs/*Al Viro2005-10-281-1/+1
| | | | | | | | | | | | | | | | | | | - ->releasepage() annotated (s/int/gfp_t), instances updated - missing gfp_t in fs/* added - fixed misannotation from the original sweep caught by bitwise checks: XFS used __nocast both for gfp_t and for flags used by XFS allocator. The latter left with unsigned int __nocast; we might want to add a different type for those but for now let's leave them alone. That, BTW, is a case when __nocast use had been actively confusing - it had been used in the same code for two different and similar types, with no way to catch misuses. Switch of gfp_t to bitwise had caught that immediately... One tricky bit is left alone to be dealt with later - mapping->flags is a mix of gfp_t and error indications. Left alone for now. Signed-off-by: Al Viro <viro@zeniv.linux.org.uk> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
* Make fsnotify possibly work better for the inode removal caseLinus Torvalds2005-09-191-1/+2
| | | | | | | Checking i_nlink is dubious, but the alternatives look even less appetizing. Signed-off-by: Linus Torvalds <torvalds@osdl.org>
* [PATCH] janitor: fs/dcache.c: list_for_each*Domen Puncer2005-09-101-12/+4
| | | | | | | | | First one is list_for_each_entry (thanks maks), second 2 list_for_each_safe. Signed-off-by: Maximilian Attems <janitor@sternwelten.at> Signed-off-by: Domen Puncer <domen@coderock.org> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
* [PATCH] fsnotify_name/inoderemoveJohn McCutchan2005-08-081-0/+7
| | | | | | | | | | | | | | | | | | | | The patch below unhooks fsnotify from vfs_unlink & vfs_rmdir. It introduces two new fsnotify calls, that are hooked in at the dcache level. This not only more closely matches how the VFS layer works, it also avoids the problem with locking and inode lifetimes. The two functions are - fsnotify_nameremove -- called when a directory entry is going away. It notifies the PARENT of the deletion. This is called from d_delete(). - inoderemove -- called when the files inode itself is going away. It notifies the inode that is being deleted. This is called from dentry_iput(). Signed-off-by: John McCutchan <ttb@tentacle.dhs.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
* [PATCH] make some things staticAdrian Bunk2005-05-051-1/+1
| | | | | | | | | | This patch makes some needlessly global identifiers static. Signed-off-by: Adrian Bunk <bunk@stusta.de> Acked-by: Arjan van de Ven <arjanv@infradead.org> Acked-by: Trond Myklebust <trond.myklebust@fys.uio.no> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
* Linux-2.6.12-rc2v2.6.12-rc2Linus Torvalds2005-04-161-0/+1764
Initial git repository build. I'm not bothering with the full history, even though we have it. We can create a separate "historical" git archive of that later if we want to, and in the meantime it's about 3.2GB when imported into git - space that would just make the early git days unnecessarily complicated, when we don't have a lot of good infrastructure for it. Let it rip!
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