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.
[maneesh@maze try]$ diffstat DCACHE_REF.patch
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 -urN linux-2.5.67-base/fs/dcache.c linux-2.5.67-DCACHE_REF/fs/dcache.c
--- linux-2.5.67-base/fs/dcache.c Mon Apr 7 23:00:42 2003
+++ linux-2.5.67-DCACHE_REF/fs/dcache.c Fri Apr 11 15:41:32 2003
@@ -155,12 +155,11 @@
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 @@
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 @@
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;
}
@@ -1016,7 +1013,6 @@
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 -urN linux-2.5.67-base/fs/exportfs/expfs.c linux-2.5.67-DCACHE_REF/fs/exportfs/expfs.c
--- linux-2.5.67-base/fs/exportfs/expfs.c Mon Apr 7 23:02:26 2003
+++ linux-2.5.67-DCACHE_REF/fs/exportfs/expfs.c Fri Apr 11 15:29:21 2003
@@ -91,7 +91,6 @@
if (dentry != result &&
acceptable(context, dentry)) {
dput(result);
- dentry->d_vfs_flags |= DCACHE_REFERENCED;
return dentry;
}
spin_lock(&dcache_lock);
@@ -271,7 +270,6 @@
if (dentry != result &&
acceptable(context, dentry)) {
dput(result);
- dentry->d_vfs_flags |= DCACHE_REFERENCED;
return dentry;
}
spin_lock(&dcache_lock);
@@ -434,7 +432,6 @@
iput(inode);
return ERR_PTR(-ENOMEM);
}
- result->d_vfs_flags |= DCACHE_REFERENCED;
return result;
}
diff -urN linux-2.5.67-base/fs/fat/inode.c linux-2.5.67-DCACHE_REF/fs/fat/inode.c
--- linux-2.5.67-base/fs/fat/inode.c Mon Apr 7 23:01:13 2003
+++ linux-2.5.67-DCACHE_REF/fs/fat/inode.c Fri Apr 11 15:29:21 2003
@@ -608,7 +608,6 @@
return ERR_PTR(-ENOMEM);
}
result->d_op = sb->s_root->d_op;
- result->d_vfs_flags |= DCACHE_REFERENCED;
return result;
}
diff -urN linux-2.5.67-base/fs/reiserfs/inode.c linux-2.5.67-DCACHE_REF/fs/reiserfs/inode.c
--- linux-2.5.67-base/fs/reiserfs/inode.c Mon Apr 7 23:01:00 2003
+++ linux-2.5.67-DCACHE_REF/fs/reiserfs/inode.c Fri Apr 11 15:29:21 2003
@@ -1260,7 +1260,6 @@
iput(inode);
return ERR_PTR(-ENOMEM);
}
- result->d_vfs_flags |= DCACHE_REFERENCED;
return result;
}
diff -urN linux-2.5.67-base/fs/xfs/linux/xfs_super.c linux-2.5.67-DCACHE_REF/fs/xfs/linux/xfs_super.c
--- linux-2.5.67-base/fs/xfs/linux/xfs_super.c Mon Apr 7 23:02:48 2003
+++ linux-2.5.67-DCACHE_REF/fs/xfs/linux/xfs_super.c Fri Apr 11 15:29:21 2003
@@ -741,7 +741,6 @@
iput(inode);
return ERR_PTR(-ENOMEM);
}
- result->d_vfs_flags |= DCACHE_REFERENCED;
return result;
}
diff -urN linux-2.5.67-base/include/linux/dcache.h linux-2.5.67-DCACHE_REF/include/linux/dcache.h
--- linux-2.5.67-base/include/linux/dcache.h Mon Apr 7 23:03:01 2003
+++ linux-2.5.67-DCACHE_REF/include/linux/dcache.h Fri Apr 11 15:29:21 2003
@@ -270,7 +270,6 @@
if (!atomic_read(&dentry->d_count))
BUG();
atomic_inc(&dentry->d_count);
- dentry->d_vfs_flags |= DCACHE_REFERENCED;
}
return dentry;
}
-- Maneesh Soni IBM Linux Technology Center, IBM India Software Lab, Bangalore. Phone: +91-80-5044999 email: maneesh@in.ibm.com http://lse.sourceforge.net/ - 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/