From f283c86afe6aa70b733d1ecebad5d9464943b774 Mon Sep 17 00:00:00 2001 From: Dave Chinner Date: Tue, 22 Mar 2011 22:23:39 +1100 Subject: [PATCH] fs: remove inode_lock from iput_final and prune_icache Now that inode state changes are protected by the inode->i_lock and the inode LRU manipulations by the inode_lru_lock, we can remove the inode_lock from prune_icache and the initial part of iput_final(). instead of using the inode_lock to protect the inode during iput_final, use the inode->i_lock instead. This protects the inode against new references being taken while we change the inode state to I_FREEING, as well as preventing prune_icache from grabbing the inode while we are manipulating it. Hence we no longer need the inode_lock in iput_final prior to setting I_FREEING on the inode. For prune_icache, we no longer need the inode_lock to protect the LRU list, and the inodes themselves are protected against freeing races by the inode->i_lock. Hence we can lift the inode_lock from prune_icache as well. Signed-off-by: Dave Chinner Signed-off-by: Al Viro --- Documentation/filesystems/Locking | 2 +- Documentation/filesystems/porting | 16 +++++++++++----- Documentation/filesystems/vfs.txt | 2 +- fs/inode.c | 17 +++-------------- fs/logfs/inode.c | 2 +- 5 files changed, 17 insertions(+), 22 deletions(-) diff --git a/Documentation/filesystems/Locking b/Documentation/filesystems/Locking index 2e994efe12cb..61b31acb9176 100644 --- a/Documentation/filesystems/Locking +++ b/Documentation/filesystems/Locking @@ -128,7 +128,7 @@ alloc_inode: destroy_inode: dirty_inode: (must not sleep) write_inode: -drop_inode: !!!inode_lock!!! +drop_inode: !!!inode->i_lock!!! evict_inode: put_super: write write_super: read diff --git a/Documentation/filesystems/porting b/Documentation/filesystems/porting index 0c986c9e8519..6e29954851a2 100644 --- a/Documentation/filesystems/porting +++ b/Documentation/filesystems/porting @@ -298,11 +298,14 @@ be used instead. It gets called whenever the inode is evicted, whether it has remaining links or not. Caller does *not* evict the pagecache or inode-associated metadata buffers; getting rid of those is responsibility of method, as it had been for ->delete_inode(). - ->drop_inode() returns int now; it's called on final iput() with inode_lock -held and it returns true if filesystems wants the inode to be dropped. As before, -generic_drop_inode() is still the default and it's been updated appropriately. -generic_delete_inode() is also alive and it consists simply of return 1. Note that -all actual eviction work is done by caller after ->drop_inode() returns. + + ->drop_inode() returns int now; it's called on final iput() with +inode->i_lock held and it returns true if filesystems wants the inode to be +dropped. As before, generic_drop_inode() is still the default and it's been +updated appropriately. generic_delete_inode() is also alive and it consists +simply of return 1. Note that all actual eviction work is done by caller after +->drop_inode() returns. + clear_inode() is gone; use end_writeback() instead. As before, it must be called exactly once on each call of ->evict_inode() (as it used to be for each call of ->delete_inode()). Unlike before, if you are using inode-associated @@ -395,6 +398,9 @@ Currently you can only have FALLOC_FL_PUNCH_HOLE with FALLOC_FL_KEEP_SIZE set, so the i_size should not change when hole punching, even when puching the end of a file off. +-- +[mandatory] + -- [mandatory] ->get_sb() is gone. Switch to use of ->mount(). Typically it's just diff --git a/Documentation/filesystems/vfs.txt b/Documentation/filesystems/vfs.txt index 306f0ae8df09..80815ed654cb 100644 --- a/Documentation/filesystems/vfs.txt +++ b/Documentation/filesystems/vfs.txt @@ -254,7 +254,7 @@ or bottom half). should be synchronous or not, not all filesystems check this flag. drop_inode: called when the last access to the inode is dropped, - with the inode_lock spinlock held. + with the inode->i_lock spinlock held. This method should be either NULL (normal UNIX filesystem semantics) or "generic_delete_inode" (for filesystems that do not diff --git a/fs/inode.c b/fs/inode.c index b19cb6ee6ca3..389f5a247599 100644 --- a/fs/inode.c +++ b/fs/inode.c @@ -650,7 +650,6 @@ static void prune_icache(int nr_to_scan) unsigned long reap = 0; down_read(&iprune_sem); - spin_lock(&inode_lock); spin_lock(&inode_lru_lock); for (nr_scanned = 0; nr_scanned < nr_to_scan; nr_scanned++) { struct inode *inode; @@ -676,8 +675,8 @@ static void prune_icache(int nr_to_scan) */ if (atomic_read(&inode->i_count) || (inode->i_state & ~I_REFERENCED)) { - spin_unlock(&inode->i_lock); list_del_init(&inode->i_lru); + spin_unlock(&inode->i_lock); inodes_stat.nr_unused--; continue; } @@ -685,20 +684,18 @@ static void prune_icache(int nr_to_scan) /* recently referenced inodes get one more pass */ if (inode->i_state & I_REFERENCED) { inode->i_state &= ~I_REFERENCED; - spin_unlock(&inode->i_lock); list_move(&inode->i_lru, &inode_lru); + spin_unlock(&inode->i_lock); continue; } if (inode_has_buffers(inode) || inode->i_data.nrpages) { __iget(inode); spin_unlock(&inode->i_lock); spin_unlock(&inode_lru_lock); - spin_unlock(&inode_lock); if (remove_inode_buffers(inode)) reap += invalidate_mapping_pages(&inode->i_data, 0, -1); iput(inode); - spin_lock(&inode_lock); spin_lock(&inode_lru_lock); if (inode != list_entry(inode_lru.next, @@ -724,7 +721,6 @@ static void prune_icache(int nr_to_scan) else __count_vm_events(PGINODESTEAL, reap); spin_unlock(&inode_lru_lock); - spin_unlock(&inode_lock); dispose_list(&freeable); up_read(&iprune_sem); @@ -1082,7 +1078,6 @@ EXPORT_SYMBOL(iunique); struct inode *igrab(struct inode *inode) { - spin_lock(&inode_lock); spin_lock(&inode->i_lock); if (!(inode->i_state & (I_FREEING|I_WILL_FREE))) { __iget(inode); @@ -1096,7 +1091,6 @@ struct inode *igrab(struct inode *inode) */ inode = NULL; } - spin_unlock(&inode_lock); return inode; } EXPORT_SYMBOL(igrab); @@ -1439,7 +1433,6 @@ static void iput_final(struct inode *inode) const struct super_operations *op = inode->i_sb->s_op; int drop; - spin_lock(&inode->i_lock); WARN_ON(inode->i_state & I_NEW); if (op && op->drop_inode) @@ -1452,16 +1445,13 @@ static void iput_final(struct inode *inode) if (!(inode->i_state & (I_DIRTY|I_SYNC))) inode_lru_list_add(inode); spin_unlock(&inode->i_lock); - spin_unlock(&inode_lock); return; } if (!drop) { inode->i_state |= I_WILL_FREE; spin_unlock(&inode->i_lock); - spin_unlock(&inode_lock); write_inode_now(inode, 1); - spin_lock(&inode_lock); spin_lock(&inode->i_lock); WARN_ON(inode->i_state & I_NEW); inode->i_state &= ~I_WILL_FREE; @@ -1470,7 +1460,6 @@ static void iput_final(struct inode *inode) inode->i_state |= I_FREEING; inode_lru_list_del(inode); spin_unlock(&inode->i_lock); - spin_unlock(&inode_lock); evict(inode); } @@ -1489,7 +1478,7 @@ void iput(struct inode *inode) if (inode) { BUG_ON(inode->i_state & I_CLEAR); - if (atomic_dec_and_lock(&inode->i_count, &inode_lock)) + if (atomic_dec_and_lock(&inode->i_count, &inode->i_lock)) iput_final(inode); } } diff --git a/fs/logfs/inode.c b/fs/logfs/inode.c index 03b8c240aeda..edfea7a3a747 100644 --- a/fs/logfs/inode.c +++ b/fs/logfs/inode.c @@ -293,7 +293,7 @@ static int logfs_write_inode(struct inode *inode, struct writeback_control *wbc) return ret; } -/* called with inode_lock held */ +/* called with inode->i_lock held */ static int logfs_drop_inode(struct inode *inode) { struct logfs_super *super = logfs_super(inode->i_sb);