DEFINE_SPINLOCK(inode_lock);
/*
- * iprune_sem provides exclusion between the kswapd or try_to_free_pages
- * icache shrinking path, and the umount path. Without this exclusion,
- * by the time prune_icache calls iput for the inode whose pages it has
- * been invalidating, or by the time it calls clear_inode & destroy_inode
- * from its final dispose_list, the struct super_block they refer to
- * (for inode->i_sb->s_op) may already have been freed and reused.
+ * iprune_sem provides exclusion between the icache shrinking and the
+ * umount path.
*
- * We make this an rwsem because the fastpath is icache shrinking. In
- * some cases a filesystem may be doing a significant amount of work in
- * its inode reclaim code, so this should improve parallelism.
+ * We don't actually need it to protect anything in the umount path,
+ * but only need to cycle through it to make sure any inode that
+ * prune_icache took off the LRU list has been fully torn down by the
+ * time we are past evict_inodes.
*/
static DECLARE_RWSEM(iprune_sem);
struct inode *inode, *next;
LIST_HEAD(dispose);
- down_write(&iprune_sem);
-
spin_lock(&inode_lock);
list_for_each_entry_safe(inode, next, &sb->s_inodes, i_sb_list) {
if (atomic_read(&inode->i_count))
continue;
-
- if (inode->i_state & (I_NEW | I_FREEING | I_WILL_FREE)) {
- WARN_ON(1);
+ if (inode->i_state & (I_NEW | I_FREEING | I_WILL_FREE))
continue;
- }
inode->i_state |= I_FREEING;
spin_unlock(&inode_lock);
dispose_list(&dispose);
+
+ /*
+ * Cycle through iprune_sem to make sure any inode that prune_icache
+ * moved off the list before we took the lock has been fully torn
+ * down.
+ */
+ down_write(&iprune_sem);
up_write(&iprune_sem);
}
/**
* invalidate_inodes - attempt to free all inodes on a superblock
* @sb: superblock to operate on
+ * @kill_dirty: flag to guide handling of dirty inodes
*
* Attempts to free all inodes for a given superblock. If there were any
* busy inodes return a non-zero value, else zero.
+ * If @kill_dirty is set, discard dirty inodes too, otherwise treat
+ * them as busy.
*/
-int invalidate_inodes(struct super_block *sb)
+int invalidate_inodes(struct super_block *sb, bool kill_dirty)
{
int busy = 0;
struct inode *inode, *next;
LIST_HEAD(dispose);
- down_write(&iprune_sem);
-
spin_lock(&inode_lock);
list_for_each_entry_safe(inode, next, &sb->s_inodes, i_sb_list) {
if (inode->i_state & (I_NEW | I_FREEING | I_WILL_FREE))
continue;
+ if (inode->i_state & I_DIRTY && !kill_dirty) {
+ busy = 1;
+ continue;
+ }
if (atomic_read(&inode->i_count)) {
busy = 1;
continue;
spin_unlock(&inode_lock);
dispose_list(&dispose);
- up_write(&iprune_sem);
return busy;
}