Make ->drop_inode() just return whether inode needs to be dropped

... and let iput_final() do the actual eviction or retention

Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>

10 files changed, 60 insertions, 103 deletions

diff --git a/drivers/staging/pohmelfs/inode.c b/drivers/staging/pohmelfs/inode.c
index e818f53ccfd..100e3a3c1b1 100644
--- a/drivers/staging/pohmelfs/inode.c
+++ b/drivers/staging/pohmelfs/inode.c
@@ -1223,7 +1223,7 @@ void pohmelfs_fill_inode(struct inode *inode, struct netfs_inode_info *info)
         }
 }
 
-static void pohmelfs_drop_inode(struct inode *inode)
+static int pohmelfs_drop_inode(struct inode *inode)
 {
         struct pohmelfs_sb *psb = POHMELFS_SB(inode->i_sb);
         struct pohmelfs_inode *pi = POHMELFS_I(inode);
@@ -1232,7 +1232,7 @@ static void pohmelfs_drop_inode(struct inode *inode)
         list_del_init(&pi->inode_entry);
         spin_unlock(&psb->ino_lock);
 
-        generic_drop_inode(inode);
+        return generic_drop_inode(inode);
 }
 
 static struct pohmelfs_inode *pohmelfs_get_inode_from_list(struct pohmelfs_sb *psb,
diff --git a/fs/btrfs/ctree.h b/fs/btrfs/ctree.h
index 394d5422ab6..eaf286abad1 100644
--- a/fs/btrfs/ctree.h
+++ b/fs/btrfs/ctree.h
@@ -2395,7 +2395,7 @@ int btrfs_write_inode(struct inode *inode, struct writeback_control *wbc);
 void btrfs_dirty_inode(struct inode *inode);
 struct inode *btrfs_alloc_inode(struct super_block *sb);
 void btrfs_destroy_inode(struct inode *inode);
-void btrfs_drop_inode(struct inode *inode);
+int btrfs_drop_inode(struct inode *inode);
 int btrfs_init_cachep(void);
 void btrfs_destroy_cachep(void);
 long btrfs_ioctl_trans_end(struct file *file);
diff --git a/fs/btrfs/inode.c b/fs/btrfs/inode.c
index ce02199ec4e..2c54f04a0bf 100644
--- a/fs/btrfs/inode.c
+++ b/fs/btrfs/inode.c
@@ -3943,7 +3943,7 @@ again:
                         if (atomic_read(&inode->i_count) > 1)
                                 d_prune_aliases(inode);
                         /*
-                         * btrfs_drop_inode will remove it from
+                         * btrfs_drop_inode will have it removed from
                          * the inode cache when its usage count
                          * hits zero.
                          */
@@ -6337,13 +6337,14 @@ free:
         kmem_cache_free(btrfs_inode_cachep, BTRFS_I(inode));
 }
 
-void btrfs_drop_inode(struct inode *inode)
+int btrfs_drop_inode(struct inode *inode)
 {
         struct btrfs_root *root = BTRFS_I(inode)->root;
-        if (inode->i_nlink > 0 && btrfs_root_refs(&root->root_item) == 0)
-                generic_delete_inode(inode);
+
+        if (btrfs_root_refs(&root->root_item) == 0)
+                return 1;
         else
-                generic_drop_inode(inode);
+                return generic_drop_inode(inode);
 }
 
 static void init_once(void *foo)
diff --git a/fs/cifs/cifsfs.c b/fs/cifs/cifsfs.c
index 8a2cf129e53..20914f5627d 100644
--- a/fs/cifs/cifsfs.c
+++ b/fs/cifs/cifsfs.c
@@ -480,14 +480,13 @@ static int cifs_remount(struct super_block *sb, int *flags, char *data)
         return 0;
 }
 
-void cifs_drop_inode(struct inode *inode)
+static int cifs_drop_inode(struct inode *inode)
 {
         struct cifs_sb_info *cifs_sb = CIFS_SB(inode->i_sb);
 
-        if (cifs_sb->mnt_cifs_flags & CIFS_MOUNT_SERVER_INUM)
-                return generic_drop_inode(inode);
-
-        return generic_delete_inode(inode);
+        /* no serverino => unconditional eviction */
+        return !(cifs_sb->mnt_cifs_flags & CIFS_MOUNT_SERVER_INUM) ||
+                generic_drop_inode(inode);
 }
 
 static const struct super_operations cifs_super_ops = {
diff --git a/fs/gfs2/super.c b/fs/gfs2/super.c
index 555f5a417c6..fa865ab37f1 100644
--- a/fs/gfs2/super.c
+++ b/fs/gfs2/super.c
@@ -1191,7 +1191,7 @@ static int gfs2_remount_fs(struct super_block *sb, int *flags, char *data)
  * node for later deallocation.
  */
 
-static void gfs2_drop_inode(struct inode *inode)
+static int gfs2_drop_inode(struct inode *inode)
 {
         struct gfs2_inode *ip = GFS2_I(inode);
 
@@ -1200,7 +1200,7 @@ static void gfs2_drop_inode(struct inode *inode)
                 if (gl && test_bit(GLF_DEMOTE, &gl->gl_flags))
                         clear_nlink(inode);
         }
-        generic_drop_inode(inode);
+        return generic_drop_inode(inode);
 }
 
 static int is_ancestor(const struct dentry *d1, const struct dentry *d2)
diff --git a/fs/inode.c b/fs/inode.c
index 82ca3562a68..0e077619cbf 100644
--- a/fs/inode.c
+++ b/fs/inode.c
@@ -1183,58 +1183,51 @@ void remove_inode_hash(struct inode *inode)
 }
 EXPORT_SYMBOL(remove_inode_hash);
 
+int generic_delete_inode(struct inode *inode)
+{
+        return 1;
+}
+EXPORT_SYMBOL(generic_delete_inode);
+
 /*
- * Tell the filesystem that this inode is no longer of any interest and should
- * be completely destroyed.
- *
- * We leave the inode in the inode hash table until *after* the filesystem's
- * ->delete_inode completes.  This ensures that an iget (such as nfsd might
- * instigate) will always find up-to-date information either in the hash or on
- * disk.
- *
- * I_FREEING is set so that no-one will take a new reference to the inode while
- * it is being deleted.
+ * Normal UNIX filesystem behaviour: delete the
+ * inode when the usage count drops to zero, and
+ * i_nlink is zero.
  */
-void generic_delete_inode(struct inode *inode)
+int generic_drop_inode(struct inode *inode)
 {
-        list_del_init(&inode->i_list);
-        list_del_init(&inode->i_sb_list);
-        WARN_ON(inode->i_state & I_NEW);
-        inode->i_state |= I_FREEING;
-        inodes_stat.nr_inodes--;
-        spin_unlock(&inode_lock);
-
-        evict(inode);
-
-        spin_lock(&inode_lock);
-        hlist_del_init(&inode->i_hash);
-        spin_unlock(&inode_lock);
-        wake_up_inode(inode);
-        BUG_ON(inode->i_state != (I_FREEING | I_CLEAR));
-        destroy_inode(inode);
+        return !inode->i_nlink || hlist_unhashed(&inode->i_hash);
 }
-EXPORT_SYMBOL(generic_delete_inode);
+EXPORT_SYMBOL_GPL(generic_drop_inode);
 
-/**
- *      generic_detach_inode - remove inode from inode lists
- *      @inode: inode to remove
- *
- *      Remove inode from inode lists, write it if it's dirty. This is just an
- *      internal VFS helper exported for hugetlbfs. Do not use!
+/*
+ * Called when we're dropping the last reference
+ * to an inode.
  *
- *      Returns 1 if inode should be completely destroyed.
+ * Call the FS "drop_inode()" function, defaulting to
+ * the legacy UNIX filesystem behaviour.  If it tells
+ * us to evict inode, do so.  Otherwise, retain inode
+ * in cache if fs is alive, sync and evict if fs is
+ * shutting down.
  */
-static int generic_detach_inode(struct inode *inode)
+static void iput_final(struct inode *inode)
 {
         struct super_block *sb = inode->i_sb;
+        const struct super_operations *op = inode->i_sb->s_op;
+        int drop;
+
+        if (op && op->drop_inode)
+                drop = op->drop_inode(inode);
+        else
+                drop = generic_drop_inode(inode);
 
-        if (!hlist_unhashed(&inode->i_hash)) {
+        if (!drop) {
                 if (!(inode->i_state & (I_DIRTY|I_SYNC)))
                         list_move(&inode->i_list, &inode_unused);
                 inodes_stat.nr_unused++;
                 if (sb->s_flags & MS_ACTIVE) {
                         spin_unlock(&inode_lock);
-                        return 0;
+                        return;
                 }
                 WARN_ON(inode->i_state & I_NEW);
                 inode->i_state |= I_WILL_FREE;
@@ -1252,53 +1245,15 @@ static int generic_detach_inode(struct inode *inode)
         inode->i_state |= I_FREEING;
         inodes_stat.nr_inodes--;
         spin_unlock(&inode_lock);
-        return 1;
-}
-
-static void generic_forget_inode(struct inode *inode)
-{
-        if (!generic_detach_inode(inode))
-                return;
         evict(inode);
+        spin_lock(&inode_lock);
+        hlist_del_init(&inode->i_hash);
+        spin_unlock(&inode_lock);
         wake_up_inode(inode);
+        BUG_ON(inode->i_state != (I_FREEING | I_CLEAR));
         destroy_inode(inode);
 }
 
-/*
- * Normal UNIX filesystem behaviour: delete the
- * inode when the usage count drops to zero, and
- * i_nlink is zero.
- */
-void generic_drop_inode(struct inode *inode)
-{
-        if (!inode->i_nlink)
-                generic_delete_inode(inode);
-        else
-                generic_forget_inode(inode);
-}
-EXPORT_SYMBOL_GPL(generic_drop_inode);
-
-/*
- * Called when we're dropping the last reference
- * to an inode.
- *
- * Call the FS "drop()" function, defaulting to
- * the legacy UNIX filesystem behaviour..
- *
- * NOTE! NOTE! NOTE! We're called with the inode lock
- * held, and the drop function is supposed to release
- * the lock!
- */
-static inline void iput_final(struct inode *inode)
-{
-        const struct super_operations *op = inode->i_sb->s_op;
-        void (*drop)(struct inode *) = generic_drop_inode;
-
-        if (op && op->drop_inode)
-                drop = op->drop_inode;
-        drop(inode);
-}
-
 /**
  *      iput    - put an inode
  *      @inode: inode to put
diff --git a/fs/logfs/inode.c b/fs/logfs/inode.c
index 78be674d95c..d8c71ece098 100644
--- a/fs/logfs/inode.c
+++ b/fs/logfs/inode.c
@@ -287,7 +287,7 @@ static int logfs_write_inode(struct inode *inode, struct writeback_control *wbc)
 }
 
 /* called with inode_lock held */
-static void logfs_drop_inode(struct inode *inode)
+static int logfs_drop_inode(struct inode *inode)
 {
         struct logfs_super *super = logfs_super(inode->i_sb);
         struct logfs_inode *li = logfs_inode(inode);
@@ -295,7 +295,7 @@ static void logfs_drop_inode(struct inode *inode)
         spin_lock(&logfs_inode_lock);
         list_move(&li->li_freeing_list, &super->s_freeing_list);
         spin_unlock(&logfs_inode_lock);
-        generic_drop_inode(inode);
+        return generic_drop_inode(inode);
 }
 
 static void logfs_set_ino_generation(struct super_block *sb,
diff --git a/fs/ocfs2/inode.c b/fs/ocfs2/inode.c
index eb7fd07c90f..0492464916b 100644
--- a/fs/ocfs2/inode.c
+++ b/fs/ocfs2/inode.c
@@ -1194,9 +1194,10 @@ void ocfs2_evict_inode(struct inode *inode)
 /* Called under inode_lock, with no more references on the
  * struct inode, so it's safe here to check the flags field
  * and to manipulate i_nlink without any other locks. */
-void ocfs2_drop_inode(struct inode *inode)
+int ocfs2_drop_inode(struct inode *inode)
 {
         struct ocfs2_inode_info *oi = OCFS2_I(inode);
+        int res;
 
         mlog_entry_void();
 
@@ -1204,11 +1205,12 @@ void ocfs2_drop_inode(struct inode *inode)
              (unsigned long long)oi->ip_blkno, inode->i_nlink, oi->ip_flags);
 
         if (oi->ip_flags & OCFS2_INODE_MAYBE_ORPHANED)
-                generic_delete_inode(inode);
+                res = 1;
         else
-                generic_drop_inode(inode);
+                res = generic_drop_inode(inode);
 
         mlog_exit_void();
+        return res;
 }
 
 /*
diff --git a/fs/ocfs2/inode.h b/fs/ocfs2/inode.h
index 975eedd7b24..6de5a869db3 100644
--- a/fs/ocfs2/inode.h
+++ b/fs/ocfs2/inode.h
@@ -124,7 +124,7 @@ static inline struct ocfs2_caching_info *INODE_CACHE(struct inode *inode)
 }
 
 void ocfs2_evict_inode(struct inode *inode);
-void ocfs2_drop_inode(struct inode *inode);
+int ocfs2_drop_inode(struct inode *inode);
 
 /* Flags for ocfs2_iget() */
 #define OCFS2_FI_FLAG_SYSFILE           0x1
diff --git a/include/linux/fs.h b/include/linux/fs.h
index 4eaa6b2e35d..8553adbda57 100644
--- a/include/linux/fs.h
+++ b/include/linux/fs.h
@@ -1562,7 +1562,7 @@ struct super_operations {
 
         void (*dirty_inode) (struct inode *);
         int (*write_inode) (struct inode *, struct writeback_control *wbc);
-        void (*drop_inode) (struct inode *);
+        int (*drop_inode) (struct inode *);
         void (*evict_inode) (struct inode *);
         void (*put_super) (struct super_block *);
         void (*write_super) (struct super_block *);
@@ -2164,8 +2164,8 @@ extern void iput(struct inode *);
 extern struct inode * igrab(struct inode *);
 extern ino_t iunique(struct super_block *, ino_t);
 extern int inode_needs_sync(struct inode *inode);
-extern void generic_delete_inode(struct inode *inode);
-extern void generic_drop_inode(struct inode *inode);
+extern int generic_delete_inode(struct inode *inode);
+extern int generic_drop_inode(struct inode *inode);
 
 extern struct inode *ilookup5_nowait(struct super_block *sb,
                 unsigned long hashval, int (*test)(struct inode *, void *),