diff options
Diffstat (limited to 'fs/inode.c')
| -rw-r--r-- | fs/inode.c | 35 |
1 files changed, 21 insertions, 14 deletions
diff --git a/fs/inode.c b/fs/inode.c index b2ba83d2c4e..76582b06ab9 100644 --- a/fs/inode.c +++ b/fs/inode.c @@ -14,6 +14,7 @@ #include <linux/module.h> #include <linux/backing-dev.h> #include <linux/wait.h> +#include <linux/rwsem.h> #include <linux/hash.h> #include <linux/swap.h> #include <linux/security.h> @@ -87,14 +88,18 @@ static struct hlist_head *inode_hashtable __read_mostly; DEFINE_SPINLOCK(inode_lock); /* - * iprune_mutex provides exclusion between the kswapd or try_to_free_pages + * 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. + * + * 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. */ -static DEFINE_MUTEX(iprune_mutex); +static DECLARE_RWSEM(iprune_sem); /* * Statistics gathering.. @@ -123,7 +128,7 @@ static void wake_up_inode(struct inode *inode) int inode_init_always(struct super_block *sb, struct inode *inode) { static const struct address_space_operations empty_aops; - static struct inode_operations empty_iops; + static const struct inode_operations empty_iops; static const struct file_operations empty_fops; struct address_space *const mapping = &inode->i_data; @@ -381,7 +386,7 @@ static int invalidate_list(struct list_head *head, struct list_head *dispose) /* * We can reschedule here without worrying about the list's * consistency because the per-sb list of inodes must not - * change during umount anymore, and because iprune_mutex keeps + * change during umount anymore, and because iprune_sem keeps * shrink_icache_memory() away. */ cond_resched_lock(&inode_lock); @@ -420,7 +425,7 @@ int invalidate_inodes(struct super_block *sb) int busy; LIST_HEAD(throw_away); - mutex_lock(&iprune_mutex); + down_write(&iprune_sem); spin_lock(&inode_lock); inotify_unmount_inodes(&sb->s_inodes); fsnotify_unmount_inodes(&sb->s_inodes); @@ -428,7 +433,7 @@ int invalidate_inodes(struct super_block *sb) spin_unlock(&inode_lock); dispose_list(&throw_away); - mutex_unlock(&iprune_mutex); + up_write(&iprune_sem); return busy; } @@ -467,7 +472,7 @@ static void prune_icache(int nr_to_scan) int nr_scanned; unsigned long reap = 0; - mutex_lock(&iprune_mutex); + down_read(&iprune_sem); spin_lock(&inode_lock); for (nr_scanned = 0; nr_scanned < nr_to_scan; nr_scanned++) { struct inode *inode; @@ -509,7 +514,7 @@ static void prune_icache(int nr_to_scan) spin_unlock(&inode_lock); dispose_list(&freeable); - mutex_unlock(&iprune_mutex); + up_read(&iprune_sem); } /* @@ -695,13 +700,15 @@ void unlock_new_inode(struct inode *inode) } #endif /* - * This is special! We do not need the spinlock - * when clearing I_LOCK, because we're guaranteed - * that nobody else tries to do anything about the - * state of the inode when it is locked, as we - * just created it (so there can be no old holders - * that haven't tested I_LOCK). + * This is special! We do not need the spinlock when clearing I_LOCK, + * because we're guaranteed that nobody else tries to do anything about + * the state of the inode when it is locked, as we just created it (so + * there can be no old holders that haven't tested I_LOCK). + * However we must emit the memory barrier so that other CPUs reliably + * see the clearing of I_LOCK after the other inode initialisation has + * completed. */ + smp_mb(); WARN_ON((inode->i_state & (I_LOCK|I_NEW)) != (I_LOCK|I_NEW)); inode->i_state &= ~(I_LOCK|I_NEW); wake_up_inode(inode); |