Political context aside, using analogies from the real world in code
is supposed to help us human programmers understand the code better.
In the case of d_genocide(), not only is it a very dark analogy, but it's
also a bad one, because d_genocide() does not actually kill any dentries.
Rename it to dput_dcache_for_umount() and rename the DCACHE_GENOCIDE
flag to DCACHE_SB_DYING.
Signed-off-by: Amir Goldstein <amir73il@xxxxxxxxx>
---
Al,
I am not usually for PC culture and I know that you are on team
"freedom of speech" ;-), but IMO this one stood out for its high ratio
of bad taste vs. usefulness.
The patch is based on your revert of "get rid of DCACHE_GENOCIDE".
I was hoping that you could queue my patch along with the revert.
BTW, why was d_genocide() only dropping refcounts on the s_root tree
and not on the s_roots trees like shrink_dcache_for_umount()?
Is it because dentries on s_roots are not supposed to be hashed?
Thanks,
Amir.
fs/dcache.c | 13 ++++++++-----
fs/internal.h | 2 +-
fs/super.c | 3 +--
include/linux/dcache.h | 2 +-
4 files changed, 11 insertions(+), 9 deletions(-)
diff --git a/fs/dcache.c b/fs/dcache.c
index 6ebccba33336..61ecc98c49a8 100644
--- a/fs/dcache.c
+++ b/fs/dcache.c
@@ -3054,24 +3054,27 @@ bool is_subdir(struct dentry *new_dentry, struct dentry *old_dentry)
}
EXPORT_SYMBOL(is_subdir);
-static enum d_walk_ret d_genocide_kill(void *data, struct dentry *dentry)
+/* make umount_check() happy before killing sb */
+static enum d_walk_ret dput_for_umount(void *data, struct dentry *dentry)
{
struct dentry *root = data;
if (dentry != root) {
if (d_unhashed(dentry) || !dentry->d_inode)
return D_WALK_SKIP;
- if (!(dentry->d_flags & DCACHE_GENOCIDE)) {
- dentry->d_flags |= DCACHE_GENOCIDE;
+ if (!(dentry->d_flags & DCACHE_SB_DYING)) {
+ dentry->d_flags |= DCACHE_SB_DYING;
dentry->d_lockref.count--;
}
}
return D_WALK_CONTINUE;
}
-void d_genocide(struct dentry *parent)
+/* drop last references before shrink_dcache_for_umount() */
+void dput_dcache_for_umount(struct super_block *sb)
{
- d_walk(parent, parent, d_genocide_kill);
+ if (sb->s_root)
+ d_walk(sb->s_root, sb->s_root, dput_for_umount);
}
void d_mark_tmpfile(struct file *file, struct inode *inode)
diff --git a/fs/internal.h b/fs/internal.h
index b67406435fc0..27bda8a3ff9d 100644
--- a/fs/internal.h
+++ b/fs/internal.h
@@ -215,10 +215,10 @@ extern char *simple_dname(struct dentry *, char *, int);
extern void dput_to_list(struct dentry *, struct list_head *);
extern void shrink_dentry_list(struct list_head *);
extern void shrink_dcache_for_umount(struct super_block *);
+extern void dput_dcache_for_umount(struct super_block *);
extern struct dentry *__d_lookup(const struct dentry *, const struct qstr *);
extern struct dentry *__d_lookup_rcu(const struct dentry *parent,
const struct qstr *name, unsigned *seq);
-extern void d_genocide(struct dentry *);
/*
* pipe.c
diff --git a/fs/super.c b/fs/super.c
index d35e85295489..42b3189fbe06 100644
--- a/fs/super.c
+++ b/fs/super.c
@@ -1235,8 +1235,7 @@ EXPORT_SYMBOL(kill_anon_super);
void kill_litter_super(struct super_block *sb)
{
- if (sb->s_root)
- d_genocide(sb->s_root);
+ dput_dcache_for_umount(sb);
kill_anon_super(sb);
}
EXPORT_SYMBOL(kill_litter_super);
diff --git a/include/linux/dcache.h b/include/linux/dcache.h
index d07cf2f1bb7d..0ce8543b64d7 100644
--- a/include/linux/dcache.h
+++ b/include/linux/dcache.h
@@ -173,7 +173,7 @@ struct dentry_operations {
#define DCACHE_DONTCACHE BIT(7) /* Purge from memory on final dput() */
#define DCACHE_CANT_MOUNT BIT(8)
-#define DCACHE_GENOCIDE BIT(9)
+#define DCACHE_SB_DYING BIT(9)
#define DCACHE_SHRINK_LIST BIT(10)
#define DCACHE_OP_WEAK_REVALIDATE BIT(11)
--
2.34.1
