From: Maneesh Soni This patch changes the way DCACHE_REFERENCED flag is used. It got messed up in dcache_rcu iterations. I hope this will be ok now. The flag was meant to be advisory flag which is used while prune_dcache() so as not to free dentries which have recently entered d_lru list. At first pass in prune_dcache the dentries marked DCACHE_REFERENCED are left with the flag reset. and they are freed in the next pass. So, now we mark the dentry as DCACHE_REFERENCED when it is first entering the d_lru list in dput() and resetthe flag in prune_dcache(). If the flag remains reset in the next call to prune_dcache(), the dentry is then freed. Also I don't think any file system have to use this flag as it is taken care by the dcache layer. The patch removes such code from a few of file systems. Moreover these filesystems were anyway doing worng thing as they were changing the flag out of dcache_lock. Changes: o dput() marks dentry DCACHE_REFERENCED when it is added to the dentry_unused list o no need to set the flag in dget, dget_locked, d_lookup as these guys anyway increments the ref count. o check the ref count in prune_dcache and use DCACHE_REFERENCED flag just for two stage aging. o remove code for setting DACACHE_REFERENCED from reiserfs, fat, xfs and exportfs. fs/dcache.c | 20 ++++++++------------ fs/exportfs/expfs.c | 3 --- fs/fat/inode.c | 1 - fs/reiserfs/inode.c | 1 - fs/xfs/linux/xfs_super.c | 1 - include/linux/dcache.h | 1 - 6 files changed, 8 insertions(+), 19 deletions(-) diff -puN fs/dcache.c~DCACHE_REFERENCED-fixes fs/dcache.c --- 25/fs/dcache.c~DCACHE_REFERENCED-fixes 2003-04-14 12:20:24.000000000 -0700 +++ 25-akpm/fs/dcache.c 2003-04-14 12:20:24.000000000 -0700 @@ -155,12 +155,11 @@ repeat: if (d_unhashed(dentry)) goto kill_it; if (list_empty(&dentry->d_lru)) { - dentry->d_vfs_flags &= ~DCACHE_REFERENCED; + dentry->d_vfs_flags |= DCACHE_REFERENCED; list_add(&dentry->d_lru, &dentry_unused); dentry_stat.nr_unused++; } spin_unlock(&dentry->d_lock); - dentry->d_vfs_flags |= DCACHE_REFERENCED; spin_unlock(&dcache_lock); return; @@ -250,7 +249,6 @@ int d_invalidate(struct dentry * dentry) static inline struct dentry * __dget_locked(struct dentry *dentry) { atomic_inc(&dentry->d_count); - dentry->d_vfs_flags |= DCACHE_REFERENCED; if (atomic_read(&dentry->d_count) == 1) { dentry_stat.nr_unused--; list_del_init(&dentry->d_lru); @@ -379,17 +377,16 @@ static void prune_dcache(int count) dentry = list_entry(tmp, struct dentry, d_lru); spin_lock(&dentry->d_lock); + /* leave inuse dentries */ + if (atomic_read(&dentry->d_count)) { + spin_unlock(&dentry->d_lock); + continue; + } /* If the dentry was recently referenced, don't free it. */ if (dentry->d_vfs_flags & DCACHE_REFERENCED) { dentry->d_vfs_flags &= ~DCACHE_REFERENCED; - - /* don't add non zero d_count dentries - * back to d_lru list - */ - if (!atomic_read(&dentry->d_count)) { - list_add(&dentry->d_lru, &dentry_unused); - dentry_stat.nr_unused++; - } + list_add(&dentry->d_lru, &dentry_unused); + dentry_stat.nr_unused++; spin_unlock(&dentry->d_lock); continue; } @@ -1027,7 +1024,6 @@ struct dentry * __d_lookup(struct dentry if (likely(move_count == dentry->d_move_count)) { if (!d_unhashed(dentry)) { atomic_inc(&dentry->d_count); - dentry->d_vfs_flags |= DCACHE_REFERENCED; found = dentry; } } diff -puN fs/exportfs/expfs.c~DCACHE_REFERENCED-fixes fs/exportfs/expfs.c --- 25/fs/exportfs/expfs.c~DCACHE_REFERENCED-fixes 2003-04-14 12:20:24.000000000 -0700 +++ 25-akpm/fs/exportfs/expfs.c 2003-04-14 12:20:24.000000000 -0700 @@ -91,7 +91,6 @@ find_exported_dentry(struct super_block if (dentry != result && acceptable(context, dentry)) { dput(result); - dentry->d_vfs_flags |= DCACHE_REFERENCED; return dentry; } spin_lock(&dcache_lock); @@ -271,7 +270,6 @@ find_exported_dentry(struct super_block if (dentry != result && acceptable(context, dentry)) { dput(result); - dentry->d_vfs_flags |= DCACHE_REFERENCED; return dentry; } spin_lock(&dcache_lock); @@ -434,7 +432,6 @@ static struct dentry *export_iget(struct iput(inode); return ERR_PTR(-ENOMEM); } - result->d_vfs_flags |= DCACHE_REFERENCED; return result; } diff -puN fs/fat/inode.c~DCACHE_REFERENCED-fixes fs/fat/inode.c --- 25/fs/fat/inode.c~DCACHE_REFERENCED-fixes 2003-04-14 12:20:24.000000000 -0700 +++ 25-akpm/fs/fat/inode.c 2003-04-14 12:20:24.000000000 -0700 @@ -608,7 +608,6 @@ struct dentry *fat_get_dentry(struct sup return ERR_PTR(-ENOMEM); } result->d_op = sb->s_root->d_op; - result->d_vfs_flags |= DCACHE_REFERENCED; return result; } diff -puN fs/reiserfs/inode.c~DCACHE_REFERENCED-fixes fs/reiserfs/inode.c --- 25/fs/reiserfs/inode.c~DCACHE_REFERENCED-fixes 2003-04-14 12:20:24.000000000 -0700 +++ 25-akpm/fs/reiserfs/inode.c 2003-04-14 12:20:24.000000000 -0700 @@ -1294,7 +1294,6 @@ struct dentry *reiserfs_get_dentry(struc iput(inode); return ERR_PTR(-ENOMEM); } - result->d_vfs_flags |= DCACHE_REFERENCED; return result; } diff -puN fs/xfs/linux/xfs_super.c~DCACHE_REFERENCED-fixes fs/xfs/linux/xfs_super.c --- 25/fs/xfs/linux/xfs_super.c~DCACHE_REFERENCED-fixes 2003-04-14 12:20:24.000000000 -0700 +++ 25-akpm/fs/xfs/linux/xfs_super.c 2003-04-14 12:20:24.000000000 -0700 @@ -741,7 +741,6 @@ linvfs_get_dentry( iput(inode); return ERR_PTR(-ENOMEM); } - result->d_vfs_flags |= DCACHE_REFERENCED; return result; } diff -puN include/linux/dcache.h~DCACHE_REFERENCED-fixes include/linux/dcache.h --- 25/include/linux/dcache.h~DCACHE_REFERENCED-fixes 2003-04-14 12:20:24.000000000 -0700 +++ 25-akpm/include/linux/dcache.h 2003-04-14 12:20:24.000000000 -0700 @@ -270,7 +270,6 @@ static inline struct dentry *dget(struct if (!atomic_read(&dentry->d_count)) BUG(); atomic_inc(&dentry->d_count); - dentry->d_vfs_flags |= DCACHE_REFERENCED; } return dentry; } _