diff --git a/drivers/base/init.c b/drivers/base/init.c index a9f57c22fb9e2f128e9d8708483ca1f631a8fa7e..dab8aa5d288898ac2be6b94a73129d8dfcd8c673 100644 --- a/drivers/base/init.c +++ b/drivers/base/init.c @@ -8,6 +8,7 @@ #include #include #include +#include #include "base.h" @@ -20,6 +21,7 @@ void __init driver_init(void) { /* These are the core pieces */ + bdi_init(&noop_backing_dev_info); devtmpfs_init(); devices_init(); buses_init(); diff --git a/fs/fs-writeback.c b/fs/fs-writeback.c index 0549aba84eca9e5477aeef6bc265a8a6dfe6b11c..f9371d249e51e0c75e43aed7c810461872b75346 100644 --- a/fs/fs-writeback.c +++ b/fs/fs-writeback.c @@ -120,6 +120,7 @@ static bool inode_io_list_move_locked(struct inode *inode, struct list_head *head) { assert_spin_locked(&wb->list_lock); + assert_spin_locked(&inode->i_lock); list_move(&inode->i_io_list, head); @@ -1260,9 +1261,9 @@ static int move_expired_inodes(struct list_head *delaying_queue, inode = wb_inode(delaying_queue->prev); if (inode_dirtied_after(inode, dirtied_before)) break; + spin_lock(&inode->i_lock); list_move(&inode->i_io_list, &tmp); moved++; - spin_lock(&inode->i_lock); inode->i_state |= I_SYNC_QUEUED; spin_unlock(&inode->i_lock); if (sb_is_blkdev_sb(inode->i_sb)) @@ -1278,7 +1279,12 @@ static int move_expired_inodes(struct list_head *delaying_queue, goto out; } - /* Move inodes from one superblock together */ + /* + * Although inode's i_io_list is moved from 'tmp' to 'dispatch_queue', + * we don't take inode->i_lock here because it is just a pointless overhead. + * Inode is already marked as I_SYNC_QUEUED so writeback list handling is + * fully under our control. + */ while (!list_empty(&tmp)) { sb = wb_inode(tmp.prev)->i_sb; list_for_each_prev_safe(pos, node, &tmp) { @@ -1700,8 +1706,8 @@ static long writeback_sb_inodes(struct super_block *sb, * We'll have another go at writing back this inode * when we completed a full scan of b_io. */ - spin_unlock(&inode->i_lock); requeue_io(inode, wb); + spin_unlock(&inode->i_lock); trace_writeback_sb_inodes_requeue(inode); continue; } @@ -2238,6 +2244,7 @@ void __mark_inode_dirty(struct inode *inode, int flags) { struct super_block *sb = inode->i_sb; int dirtytime; + struct bdi_writeback *wb = NULL; trace_writeback_mark_inode_dirty(inode, flags); @@ -2279,6 +2286,17 @@ void __mark_inode_dirty(struct inode *inode, int flags) inode->i_state &= ~I_DIRTY_TIME; inode->i_state |= flags; + /* + * Grab inode's wb early because it requires dropping i_lock and we + * need to make sure following checks happen atomically with dirty + * list handling so that we don't move inodes under flush worker's + * hands. + */ + if (!was_dirty) { + wb = locked_inode_to_wb_and_lock_list(inode); + spin_lock(&inode->i_lock); + } + /* * If the inode is queued for writeback by flush worker, just * update its dirty state. Once the flush worker is done with @@ -2286,7 +2304,7 @@ void __mark_inode_dirty(struct inode *inode, int flags) * list, based upon its state. */ if (inode->i_state & I_SYNC_QUEUED) - goto out_unlock_inode; + goto out_unlock; /* * Only add valid (hashed) inodes to the superblock's @@ -2294,22 +2312,19 @@ void __mark_inode_dirty(struct inode *inode, int flags) */ if (!S_ISBLK(inode->i_mode)) { if (inode_unhashed(inode)) - goto out_unlock_inode; + goto out_unlock; } if (inode->i_state & I_FREEING) - goto out_unlock_inode; + goto out_unlock; /* * If the inode was already on b_dirty/b_io/b_more_io, don't * reposition it (that would break b_dirty time-ordering). */ if (!was_dirty) { - struct bdi_writeback *wb; struct list_head *dirty_list; bool wakeup_bdi = false; - wb = locked_inode_to_wb_and_lock_list(inode); - inode->dirtied_when = jiffies; if (dirtytime) inode->dirtied_time_when = jiffies; @@ -2323,6 +2338,7 @@ void __mark_inode_dirty(struct inode *inode, int flags) dirty_list); spin_unlock(&wb->list_lock); + spin_unlock(&inode->i_lock); trace_writeback_dirty_inode_enqueue(inode); /* @@ -2337,6 +2353,9 @@ void __mark_inode_dirty(struct inode *inode, int flags) return; } } +out_unlock: + if (wb) + spin_unlock(&wb->list_lock); out_unlock_inode: spin_unlock(&inode->i_lock); } diff --git a/fs/inode.c b/fs/inode.c index c4eaa1db9d1aff3a2a84aaf0041bc1f4a646563b..6fa868738f94183ed7582ff33968e59b55bf1550 100644 --- a/fs/inode.c +++ b/fs/inode.c @@ -28,7 +28,7 @@ * Inode locking rules: * * inode->i_lock protects: - * inode->i_state, inode->i_hash, __iget() + * inode->i_state, inode->i_hash, __iget(), inode->i_io_list * Inode LRU list locks protect: * inode->i_sb->s_inode_lru, inode->i_lru * inode->i_sb->s_inode_list_lock protects: diff --git a/include/linux/backing-dev.h b/include/linux/backing-dev.h index b10df87d6c348dc3054c14b570f702270fc3829a..be153f99bf2ffabdb1d23f905a48e9b5310387e4 100644 --- a/include/linux/backing-dev.h +++ b/include/linux/backing-dev.h @@ -131,6 +131,8 @@ int bdi_set_strict_limit(struct backing_dev_info *bdi, unsigned int strict_limit extern struct backing_dev_info noop_backing_dev_info; +int bdi_init(struct backing_dev_info *bdi); + /** * writeback_in_progress - determine whether there is writeback in progress * @wb: bdi_writeback of interest diff --git a/mm/backing-dev.c b/mm/backing-dev.c index 9b1f1141407b2e0e54751423dc3417a63a13bb67..bc406d62c6175dbcac92da9682e7f2aa047816dc 100644 --- a/mm/backing-dev.c +++ b/mm/backing-dev.c @@ -356,20 +356,13 @@ static __init int bdi_class_init(void) } postcore_initcall(bdi_class_init); -static int bdi_init(struct backing_dev_info *bdi); - static int __init default_bdi_init(void) { - int err; - bdi_wq = alloc_workqueue("writeback", WQ_MEM_RECLAIM | WQ_UNBOUND | WQ_SYSFS, 0); if (!bdi_wq) return -ENOMEM; - - err = bdi_init(&noop_backing_dev_info); - - return err; + return 0; } subsys_initcall(default_bdi_init); @@ -899,7 +892,7 @@ static void cgwb_remove_from_bdi_list(struct bdi_writeback *wb) #endif /* CONFIG_CGROUP_WRITEBACK */ -static int bdi_init(struct backing_dev_info *bdi) +int bdi_init(struct backing_dev_info *bdi) { int ret;