Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753173Ab0K0K0l (ORCPT ); Sat, 27 Nov 2010 05:26:41 -0500 Received: from ipmail04.adl6.internode.on.net ([150.101.137.141]:34786 "EHLO ipmail04.adl6.internode.on.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752824Ab0K0K0a (ORCPT ); Sat, 27 Nov 2010 05:26:30 -0500 X-IronPort-Anti-Spam-Filtered: true X-IronPort-Anti-Spam-Result: AvsEAO1p8Ex5Lcx2/2dsb2JhbACjC3K9doVHBIph Message-Id: <8cd580929bffd56175233f3bc39583a44e3e4497.1290852959.git.npiggin@kernel.dk> In-Reply-To: References: From: Nick Piggin Date: Sat, 27 Nov 2010 20:44:43 +1100 Subject: [PATCH 13/46] fs: dcache scale dentry refcount To: linux-fsdevel@vger.kernel.org Cc: linux-kernel@vger.kernel.org Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 21826 Lines: 686 Make d_count non-atomic and protect it with d_lock. This allows us to ensure a 0 refcount dentry remains 0 without dcache_lock. It is also fairly natural when we start protecting many other dentry members with d_lock. Signed-off-by: Nick Piggin --- arch/powerpc/platforms/cell/spufs/inode.c | 2 +- drivers/infiniband/hw/ipath/ipath_fs.c | 2 +- drivers/infiniband/hw/qib/qib_fs.c | 2 +- fs/autofs4/expire.c | 8 +- fs/autofs4/root.c | 6 +- fs/ceph/dir.c | 4 +- fs/ceph/inode.c | 4 +- fs/ceph/mds_client.c | 2 +- fs/coda/dir.c | 2 +- fs/configfs/dir.c | 3 +- fs/configfs/inode.c | 2 +- fs/dcache.c | 106 ++++++++++++++++++++++------- fs/ecryptfs/inode.c | 2 +- fs/locks.c | 2 +- fs/namei.c | 2 +- fs/nfs/dir.c | 6 +- fs/nfs/unlink.c | 2 +- fs/nfsd/vfs.c | 5 +- fs/nilfs2/super.c | 2 +- include/linux/dcache.h | 29 ++++---- kernel/cgroup.c | 2 - 21 files changed, 126 insertions(+), 69 deletions(-) diff --git a/arch/powerpc/platforms/cell/spufs/inode.c b/arch/powerpc/platforms/cell/spufs/inode.c index 3532b92..29a406a 100644 --- a/arch/powerpc/platforms/cell/spufs/inode.c +++ b/arch/powerpc/platforms/cell/spufs/inode.c @@ -162,7 +162,7 @@ static void spufs_prune_dir(struct dentry *dir) spin_lock(&dcache_lock); spin_lock(&dentry->d_lock); if (!(d_unhashed(dentry)) && dentry->d_inode) { - dget_locked(dentry); + dget_locked_dlock(dentry); __d_drop(dentry); spin_unlock(&dentry->d_lock); simple_unlink(dir->d_inode, dentry); diff --git a/drivers/infiniband/hw/ipath/ipath_fs.c b/drivers/infiniband/hw/ipath/ipath_fs.c index 8c8afc7..18aee04 100644 --- a/drivers/infiniband/hw/ipath/ipath_fs.c +++ b/drivers/infiniband/hw/ipath/ipath_fs.c @@ -280,7 +280,7 @@ static int remove_file(struct dentry *parent, char *name) spin_lock(&dcache_lock); spin_lock(&tmp->d_lock); if (!(d_unhashed(tmp) && tmp->d_inode)) { - dget_locked(tmp); + dget_locked_dlock(tmp); __d_drop(tmp); spin_unlock(&tmp->d_lock); spin_unlock(&dcache_lock); diff --git a/drivers/infiniband/hw/qib/qib_fs.c b/drivers/infiniband/hw/qib/qib_fs.c index f99bddc..fe4b242 100644 --- a/drivers/infiniband/hw/qib/qib_fs.c +++ b/drivers/infiniband/hw/qib/qib_fs.c @@ -456,7 +456,7 @@ static int remove_file(struct dentry *parent, char *name) spin_lock(&dcache_lock); spin_lock(&tmp->d_lock); if (!(d_unhashed(tmp) && tmp->d_inode)) { - dget_locked(tmp); + dget_locked_dlock(tmp); __d_drop(tmp); spin_unlock(&tmp->d_lock); spin_unlock(&dcache_lock); diff --git a/fs/autofs4/expire.c b/fs/autofs4/expire.c index a796c94..413b564 100644 --- a/fs/autofs4/expire.c +++ b/fs/autofs4/expire.c @@ -198,7 +198,7 @@ static int autofs4_tree_busy(struct vfsmount *mnt, else ino_count++; - if (atomic_read(&p->d_count) > ino_count) { + if (p->d_count > ino_count) { top_ino->last_used = jiffies; dput(p); return 1; @@ -347,7 +347,7 @@ struct dentry *autofs4_expire_indirect(struct super_block *sb, /* Path walk currently on this dentry? */ ino_count = atomic_read(&ino->count) + 2; - if (atomic_read(&dentry->d_count) > ino_count) + if (dentry->d_count > ino_count) goto next; /* Can we umount this guy */ @@ -369,7 +369,7 @@ struct dentry *autofs4_expire_indirect(struct super_block *sb, if (!exp_leaves) { /* Path walk currently on this dentry? */ ino_count = atomic_read(&ino->count) + 1; - if (atomic_read(&dentry->d_count) > ino_count) + if (dentry->d_count > ino_count) goto next; if (!autofs4_tree_busy(mnt, dentry, timeout, do_now)) { @@ -383,7 +383,7 @@ struct dentry *autofs4_expire_indirect(struct super_block *sb, } else { /* Path walk currently on this dentry? */ ino_count = atomic_read(&ino->count) + 1; - if (atomic_read(&dentry->d_count) > ino_count) + if (dentry->d_count > ino_count) goto next; expired = autofs4_check_leaves(mnt, dentry, timeout, do_now); diff --git a/fs/autofs4/root.c b/fs/autofs4/root.c index d5c1401..dc7e64b 100644 --- a/fs/autofs4/root.c +++ b/fs/autofs4/root.c @@ -436,7 +436,7 @@ static struct dentry *autofs4_lookup_active(struct dentry *dentry) spin_lock(&active->d_lock); /* Already gone? */ - if (atomic_read(&active->d_count) == 0) + if (active->d_count == 0) goto next; qstr = &active->d_name; @@ -452,7 +452,7 @@ static struct dentry *autofs4_lookup_active(struct dentry *dentry) goto next; if (d_unhashed(active)) { - dget(active); + dget_dlock(active); spin_unlock(&active->d_lock); spin_unlock(&sbi->lookup_lock); spin_unlock(&dcache_lock); @@ -507,7 +507,7 @@ static struct dentry *autofs4_lookup_expiring(struct dentry *dentry) goto next; if (d_unhashed(expiring)) { - dget(expiring); + dget_dlock(expiring); spin_unlock(&expiring->d_lock); spin_unlock(&sbi->lookup_lock); spin_unlock(&dcache_lock); diff --git a/fs/ceph/dir.c b/fs/ceph/dir.c index 7d447af..599b011 100644 --- a/fs/ceph/dir.c +++ b/fs/ceph/dir.c @@ -149,7 +149,9 @@ more: di = ceph_dentry(dentry); } - atomic_inc(&dentry->d_count); + spin_lock(&dentry->d_lock); + dentry->d_count++; + spin_unlock(&dentry->d_lock); spin_unlock(&dcache_lock); dout(" %llu (%llu) dentry %p %.*s %p\n", di->offset, filp->f_pos, diff --git a/fs/ceph/inode.c b/fs/ceph/inode.c index bf12865..bb68c79 100644 --- a/fs/ceph/inode.c +++ b/fs/ceph/inode.c @@ -879,8 +879,8 @@ static struct dentry *splice_dentry(struct dentry *dn, struct inode *in, } else if (realdn) { dout("dn %p (%d) spliced with %p (%d) " "inode %p ino %llx.%llx\n", - dn, atomic_read(&dn->d_count), - realdn, atomic_read(&realdn->d_count), + dn, dn->d_count, + realdn, realdn->d_count, realdn->d_inode, ceph_vinop(realdn->d_inode)); dput(dn); dn = realdn; diff --git a/fs/ceph/mds_client.c b/fs/ceph/mds_client.c index 098b185..b110246 100644 --- a/fs/ceph/mds_client.c +++ b/fs/ceph/mds_client.c @@ -1454,7 +1454,7 @@ retry: *base = ceph_ino(temp->d_inode); *plen = len; dout("build_path on %p %d built %llx '%.*s'\n", - dentry, atomic_read(&dentry->d_count), *base, len, path); + dentry, dentry->d_count, *base, len, path); return path; } diff --git a/fs/coda/dir.c b/fs/coda/dir.c index 4cce3b0..9e37e8b 100644 --- a/fs/coda/dir.c +++ b/fs/coda/dir.c @@ -559,7 +559,7 @@ static int coda_dentry_revalidate(struct dentry *de, struct nameidata *nd) if (cii->c_flags & C_FLUSH) coda_flag_inode_children(inode, C_FLUSH); - if (atomic_read(&de->d_count) > 1) + if (de->d_count > 1) /* pretend it's valid, but don't change the flags */ goto out; diff --git a/fs/configfs/dir.c b/fs/configfs/dir.c index 1001557..5825780 100644 --- a/fs/configfs/dir.c +++ b/fs/configfs/dir.c @@ -399,8 +399,7 @@ static void remove_dir(struct dentry * d) if (d->d_inode) simple_rmdir(parent->d_inode,d); - pr_debug(" o %s removing done (%d)\n",d->d_name.name, - atomic_read(&d->d_count)); + pr_debug(" o %s removing done (%d)\n",d->d_name.name, d->d_count); dput(parent); } diff --git a/fs/configfs/inode.c b/fs/configfs/inode.c index 253476d..79b3776 100644 --- a/fs/configfs/inode.c +++ b/fs/configfs/inode.c @@ -253,7 +253,7 @@ void configfs_drop_dentry(struct configfs_dirent * sd, struct dentry * parent) spin_lock(&dcache_lock); spin_lock(&dentry->d_lock); if (!(d_unhashed(dentry) && dentry->d_inode)) { - dget_locked(dentry); + dget_locked_dlock(dentry); __d_drop(dentry); spin_unlock(&dentry->d_lock); spin_unlock(&dcache_lock); diff --git a/fs/dcache.c b/fs/dcache.c index aa410b6..2e04131 100644 --- a/fs/dcache.c +++ b/fs/dcache.c @@ -45,6 +45,7 @@ * - d_flags * - d_name * - d_lru + * - d_count * * Ordering: * dcache_lock @@ -119,6 +120,7 @@ static void __d_free(struct rcu_head *head) */ static void d_free(struct dentry *dentry) { + BUG_ON(dentry->d_count); percpu_counter_dec(&nr_dentry); if (dentry->d_op && dentry->d_op->d_release) dentry->d_op->d_release(dentry); @@ -216,8 +218,11 @@ static struct dentry *d_kill(struct dentry *dentry) struct dentry *parent; list_del(&dentry->d_u.d_child); - /*drops the locks, at that point nobody can reach this dentry */ dentry_iput(dentry); + /* + * dentry_iput drops the locks, at which point nobody (except + * transient RCU lookups) can reach this dentry. + */ if (IS_ROOT(dentry)) parent = NULL; else @@ -261,13 +266,23 @@ void dput(struct dentry *dentry) return; repeat: - if (atomic_read(&dentry->d_count) == 1) + if (dentry->d_count == 1) might_sleep(); - if (!atomic_dec_and_lock(&dentry->d_count, &dcache_lock)) - return; - spin_lock(&dentry->d_lock); - if (atomic_read(&dentry->d_count)) { + if (dentry->d_count == 1) { + if (!spin_trylock(&dcache_lock)) { + /* + * Something of a livelock possibility we could avoid + * by taking dcache_lock and trying again, but we + * want to reduce dcache_lock anyway so this will + * get improved. + */ + spin_unlock(&dentry->d_lock); + goto repeat; + } + } + dentry->d_count--; + if (dentry->d_count) { spin_unlock(&dentry->d_lock); spin_unlock(&dcache_lock); return; @@ -347,7 +362,7 @@ int d_invalidate(struct dentry * dentry) * working directory or similar). */ spin_lock(&dentry->d_lock); - if (atomic_read(&dentry->d_count) > 1) { + if (dentry->d_count > 1) { if (dentry->d_inode && S_ISDIR(dentry->d_inode->i_mode)) { spin_unlock(&dentry->d_lock); spin_unlock(&dcache_lock); @@ -362,29 +377,61 @@ int d_invalidate(struct dentry * dentry) } EXPORT_SYMBOL(d_invalidate); -/* This should be called _only_ with dcache_lock held */ +/* This must be called with dcache_lock and d_lock held */ static inline struct dentry * __dget_locked_dlock(struct dentry *dentry) { - atomic_inc(&dentry->d_count); + dentry->d_count++; dentry_lru_del(dentry); return dentry; } +/* This should be called _only_ with dcache_lock held */ static inline struct dentry * __dget_locked(struct dentry *dentry) { - atomic_inc(&dentry->d_count); spin_lock(&dentry->d_lock); - dentry_lru_del(dentry); + __dget_locked_dlock(dentry); spin_unlock(&dentry->d_lock); return dentry; } +struct dentry * dget_locked_dlock(struct dentry *dentry) +{ + return __dget_locked_dlock(dentry); +} + struct dentry * dget_locked(struct dentry *dentry) { return __dget_locked(dentry); } EXPORT_SYMBOL(dget_locked); +struct dentry *dget_parent(struct dentry *dentry) +{ + struct dentry *ret; + +repeat: + spin_lock(&dentry->d_lock); + ret = dentry->d_parent; + if (!ret) + goto out; + if (dentry == ret) { + ret->d_count++; + goto out; + } + if (!spin_trylock(&ret->d_lock)) { + spin_unlock(&dentry->d_lock); + cpu_relax(); + goto repeat; + } + BUG_ON(!ret->d_count); + ret->d_count++; + spin_unlock(&ret->d_lock); +out: + spin_unlock(&dentry->d_lock); + return ret; +} +EXPORT_SYMBOL(dget_parent); + /** * d_find_alias - grab a hashed alias of inode * @inode: inode in question @@ -453,7 +500,7 @@ restart: spin_lock(&dcache_lock); list_for_each_entry(dentry, &inode->i_dentry, d_alias) { spin_lock(&dentry->d_lock); - if (!atomic_read(&dentry->d_count)) { + if (!dentry->d_count) { __dget_locked_dlock(dentry); __d_drop(dentry); spin_unlock(&dentry->d_lock); @@ -488,7 +535,10 @@ static void prune_one_dentry(struct dentry * dentry) */ while (dentry) { spin_lock(&dcache_lock); - if (!atomic_dec_and_lock(&dentry->d_count, &dentry->d_lock)) { + spin_lock(&dentry->d_lock); + dentry->d_count--; + if (dentry->d_count) { + spin_unlock(&dentry->d_lock); spin_unlock(&dcache_lock); return; } @@ -520,7 +570,7 @@ static void shrink_dentry_list(struct list_head *list) * the LRU because of laziness during lookup. Do not free * it - just keep it off the LRU list. */ - if (atomic_read(&dentry->d_count)) { + if (dentry->d_count) { spin_unlock(&dentry->d_lock); continue; } @@ -741,7 +791,7 @@ static void shrink_dcache_for_umount_subtree(struct dentry *dentry) do { struct inode *inode; - if (atomic_read(&dentry->d_count) != 0) { + if (dentry->d_count != 0) { printk(KERN_ERR "BUG: Dentry %p{i=%lx,n=%s}" " still in use (%d)" @@ -750,7 +800,7 @@ static void shrink_dcache_for_umount_subtree(struct dentry *dentry) dentry->d_inode ? dentry->d_inode->i_ino : 0UL, dentry->d_name.name, - atomic_read(&dentry->d_count), + dentry->d_count, dentry->d_sb->s_type->name, dentry->d_sb->s_id); BUG(); @@ -760,7 +810,9 @@ static void shrink_dcache_for_umount_subtree(struct dentry *dentry) parent = NULL; else { parent = dentry->d_parent; - atomic_dec(&parent->d_count); + spin_lock(&parent->d_lock); + parent->d_count--; + spin_unlock(&parent->d_lock); } list_del(&dentry->d_u.d_child); @@ -811,7 +863,9 @@ void shrink_dcache_for_umount(struct super_block *sb) dentry = sb->s_root; sb->s_root = NULL; - atomic_dec(&dentry->d_count); + spin_lock(&dentry->d_lock); + dentry->d_count--; + spin_unlock(&dentry->d_lock); shrink_dcache_for_umount_subtree(dentry); while (!hlist_empty(&sb->s_anon)) { @@ -908,7 +962,7 @@ resume: * move only zero ref count dentries to the end * of the unused list for prune_dcache */ - if (!atomic_read(&dentry->d_count)) { + if (!dentry->d_count) { dentry_lru_move_tail(dentry); found++; } else { @@ -1029,7 +1083,7 @@ struct dentry *d_alloc(struct dentry * parent, const struct qstr *name) memcpy(dname, name->name, name->len); dname[name->len] = 0; - atomic_set(&dentry->d_count, 1); + dentry->d_count = 1; dentry->d_flags = DCACHE_UNHASHED; spin_lock_init(&dentry->d_lock); dentry->d_inode = NULL; @@ -1517,7 +1571,7 @@ struct dentry * __d_lookup(struct dentry * parent, struct qstr * name) goto next; } - atomic_inc(&dentry->d_count); + dentry->d_count++; found = dentry; spin_unlock(&dentry->d_lock); break; @@ -1614,7 +1668,7 @@ void d_delete(struct dentry * dentry) spin_lock(&dcache_lock); spin_lock(&dentry->d_lock); isdir = S_ISDIR(dentry->d_inode->i_mode); - if (atomic_read(&dentry->d_count) == 1) { + if (dentry->d_count == 1) { dentry->d_flags &= ~DCACHE_CANT_MOUNT; dentry_iput(dentry); fsnotify_nameremove(dentry, isdir); @@ -2428,11 +2482,15 @@ resume: this_parent = dentry; goto repeat; } - atomic_dec(&dentry->d_count); + spin_lock(&dentry->d_lock); + dentry->d_count--; + spin_unlock(&dentry->d_lock); } if (this_parent != root) { next = this_parent->d_u.d_child.next; - atomic_dec(&this_parent->d_count); + spin_lock(&this_parent->d_lock); + this_parent->d_count--; + spin_unlock(&this_parent->d_lock); this_parent = this_parent->d_parent; goto resume; } diff --git a/fs/ecryptfs/inode.c b/fs/ecryptfs/inode.c index a1ed7a7..5e5c7ec 100644 --- a/fs/ecryptfs/inode.c +++ b/fs/ecryptfs/inode.c @@ -260,7 +260,7 @@ int ecryptfs_lookup_and_interpose_lower(struct dentry *ecryptfs_dentry, ecryptfs_dentry->d_parent)); lower_inode = lower_dentry->d_inode; fsstack_copy_attr_atime(ecryptfs_dir_inode, lower_dir_dentry->d_inode); - BUG_ON(!atomic_read(&lower_dentry->d_count)); + BUG_ON(!lower_dentry->d_count); ecryptfs_set_dentry_private(ecryptfs_dentry, kmem_cache_alloc(ecryptfs_dentry_info_cache, GFP_KERNEL)); diff --git a/fs/locks.c b/fs/locks.c index 8729347..08415b2 100644 --- a/fs/locks.c +++ b/fs/locks.c @@ -1389,7 +1389,7 @@ int generic_setlease(struct file *filp, long arg, struct file_lock **flp) if ((arg == F_RDLCK) && (atomic_read(&inode->i_writecount) > 0)) goto out; if ((arg == F_WRLCK) - && ((atomic_read(&dentry->d_count) > 1) + && ((dentry->d_count > 1) || (atomic_read(&inode->i_count) > 1))) goto out; } diff --git a/fs/namei.c b/fs/namei.c index bf6821a..3081ea3 100644 --- a/fs/namei.c +++ b/fs/namei.c @@ -2130,7 +2130,7 @@ void dentry_unhash(struct dentry *dentry) shrink_dcache_parent(dentry); spin_lock(&dcache_lock); spin_lock(&dentry->d_lock); - if (atomic_read(&dentry->d_count) == 2) + if (dentry->d_count == 2) __d_drop(dentry); spin_unlock(&dentry->d_lock); spin_unlock(&dcache_lock); diff --git a/fs/nfs/dir.c b/fs/nfs/dir.c index 0f7798a..34ef2dd 100644 --- a/fs/nfs/dir.c +++ b/fs/nfs/dir.c @@ -1730,7 +1730,7 @@ static int nfs_unlink(struct inode *dir, struct dentry *dentry) spin_lock(&dcache_lock); spin_lock(&dentry->d_lock); - if (atomic_read(&dentry->d_count) > 1) { + if (dentry->d_count > 1) { spin_unlock(&dentry->d_lock); spin_unlock(&dcache_lock); /* Start asynchronous writeout of the inode */ @@ -1878,7 +1878,7 @@ static int nfs_rename(struct inode *old_dir, struct dentry *old_dentry, dfprintk(VFS, "NFS: rename(%s/%s -> %s/%s, ct=%d)\n", old_dentry->d_parent->d_name.name, old_dentry->d_name.name, new_dentry->d_parent->d_name.name, new_dentry->d_name.name, - atomic_read(&new_dentry->d_count)); + new_dentry->d_count); /* * For non-directories, check whether the target is busy and if so, @@ -1896,7 +1896,7 @@ static int nfs_rename(struct inode *old_dir, struct dentry *old_dentry, rehash = new_dentry; } - if (atomic_read(&new_dentry->d_count) > 2) { + if (new_dentry->d_count > 2) { int err; /* copy the target dentry's name */ diff --git a/fs/nfs/unlink.c b/fs/nfs/unlink.c index 7bdec85..8fe9eb4 100644 --- a/fs/nfs/unlink.c +++ b/fs/nfs/unlink.c @@ -496,7 +496,7 @@ nfs_sillyrename(struct inode *dir, struct dentry *dentry) dfprintk(VFS, "NFS: silly-rename(%s/%s, ct=%d)\n", dentry->d_parent->d_name.name, dentry->d_name.name, - atomic_read(&dentry->d_count)); + dentry->d_count); nfs_inc_stats(dir, NFSIOS_SILLYRENAME); /* diff --git a/fs/nfsd/vfs.c b/fs/nfsd/vfs.c index 184938f..3a35902 100644 --- a/fs/nfsd/vfs.c +++ b/fs/nfsd/vfs.c @@ -1756,8 +1756,7 @@ nfsd_rename(struct svc_rqst *rqstp, struct svc_fh *ffhp, char *fname, int flen, goto out_dput_new; if (svc_msnfs(ffhp) && - ((atomic_read(&odentry->d_count) > 1) - || (atomic_read(&ndentry->d_count) > 1))) { + ((odentry->d_count > 1) || (ndentry->d_count > 1))) { host_err = -EPERM; goto out_dput_new; } @@ -1843,7 +1842,7 @@ nfsd_unlink(struct svc_rqst *rqstp, struct svc_fh *fhp, int type, if (type != S_IFDIR) { /* It's UNLINK */ #ifdef MSNFS if ((fhp->fh_export->ex_flags & NFSEXP_MSNFS) && - (atomic_read(&rdentry->d_count) > 1)) { + (rdentry->d_count > 1)) { host_err = -EPERM; } else #endif diff --git a/fs/nilfs2/super.c b/fs/nilfs2/super.c index f804d41..d36fc7e 100644 --- a/fs/nilfs2/super.c +++ b/fs/nilfs2/super.c @@ -838,7 +838,7 @@ static int nilfs_attach_snapshot(struct super_block *s, __u64 cno, static int nilfs_tree_was_touched(struct dentry *root_dentry) { - return atomic_read(&root_dentry->d_count) > 1; + return root_dentry->d_count > 1; } /** diff --git a/include/linux/dcache.h b/include/linux/dcache.h index 7ce20f5..06f6f58 100644 --- a/include/linux/dcache.h +++ b/include/linux/dcache.h @@ -87,7 +87,7 @@ full_name_hash(const unsigned char *name, unsigned int len) #endif struct dentry { - atomic_t d_count; + unsigned int d_count; /* protected by d_lock */ unsigned int d_flags; /* protected by d_lock */ spinlock_t d_lock; /* per dentry lock */ int d_mounted; @@ -329,17 +329,28 @@ extern char *dentry_path(struct dentry *, char *, int); * needs and they take necessary precautions) you should hold dcache_lock * and call dget_locked() instead of dget(). */ - +static inline struct dentry *dget_dlock(struct dentry *dentry) +{ + if (dentry) { + BUG_ON(!dentry->d_count); + dentry->d_count++; + } + return dentry; +} static inline struct dentry *dget(struct dentry *dentry) { if (dentry) { - BUG_ON(!atomic_read(&dentry->d_count)); - atomic_inc(&dentry->d_count); + spin_lock(&dentry->d_lock); + dget_dlock(dentry); + spin_unlock(&dentry->d_lock); } return dentry; } extern struct dentry * dget_locked(struct dentry *); +extern struct dentry * dget_locked_dlock(struct dentry *); + +extern struct dentry *dget_parent(struct dentry *dentry); /** * d_unhashed - is dentry hashed @@ -370,16 +381,6 @@ static inline void dont_mount(struct dentry *dentry) spin_unlock(&dentry->d_lock); } -static inline struct dentry *dget_parent(struct dentry *dentry) -{ - struct dentry *ret; - - spin_lock(&dentry->d_lock); - ret = dget(dentry->d_parent); - spin_unlock(&dentry->d_lock); - return ret; -} - extern void dput(struct dentry *); static inline int d_mountpoint(struct dentry *dentry) diff --git a/kernel/cgroup.c b/kernel/cgroup.c index 66a416b..7ead732 100644 --- a/kernel/cgroup.c +++ b/kernel/cgroup.c @@ -3638,9 +3638,7 @@ again: list_del(&cgrp->sibling); cgroup_unlock_hierarchy(cgrp->root); - spin_lock(&cgrp->dentry->d_lock); d = dget(cgrp->dentry); - spin_unlock(&d->d_lock); cgroup_d_remove_dir(d); dput(d); -- 1.7.1 -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/