Commit 250df6ed authored by Dave Chinner's avatar Dave Chinner Committed by Al Viro

fs: protect inode->i_state with inode->i_lock

Protect inode state transitions and validity checks with the
inode->i_lock. This enables us to make inode state transitions
independently of the inode_lock and is the first step to peeling
away the inode_lock from the code.

This requires that __iget() is done atomically with i_state checks
during list traversals so that we don't race with another thread
marking the inode I_FREEING between the state check and grabbing the
reference.

Also remove the unlock_new_inode() memory barrier optimisation
required to avoid taking the inode_lock when clearing I_NEW.
Simplify the code by simply taking the inode->i_lock around the
state change and wakeup. Because the wakeup is no longer tricky,
remove the wake_up_inode() function and open code the wakeup where
necessary.
Signed-off-by: default avatarDave Chinner <dchinner@redhat.com>
Signed-off-by: default avatarAl Viro <viro@zeniv.linux.org.uk>
parent 3dc8fe4d
...@@ -56,9 +56,11 @@ static void bdev_inode_switch_bdi(struct inode *inode, ...@@ -56,9 +56,11 @@ static void bdev_inode_switch_bdi(struct inode *inode,
struct backing_dev_info *dst) struct backing_dev_info *dst)
{ {
spin_lock(&inode_lock); spin_lock(&inode_lock);
spin_lock(&inode->i_lock);
inode->i_data.backing_dev_info = dst; inode->i_data.backing_dev_info = dst;
if (inode->i_state & I_DIRTY) if (inode->i_state & I_DIRTY)
list_move(&inode->i_wb_list, &dst->wb.b_dirty); list_move(&inode->i_wb_list, &dst->wb.b_dirty);
spin_unlock(&inode->i_lock);
spin_unlock(&inode_lock); spin_unlock(&inode_lock);
} }
......
...@@ -1144,7 +1144,7 @@ __getblk_slow(struct block_device *bdev, sector_t block, int size) ...@@ -1144,7 +1144,7 @@ __getblk_slow(struct block_device *bdev, sector_t block, int size)
* inode list. * inode list.
* *
* mark_buffer_dirty() is atomic. It takes bh->b_page->mapping->private_lock, * mark_buffer_dirty() is atomic. It takes bh->b_page->mapping->private_lock,
* mapping->tree_lock and the global inode_lock. * mapping->tree_lock and mapping->host->i_lock.
*/ */
void mark_buffer_dirty(struct buffer_head *bh) void mark_buffer_dirty(struct buffer_head *bh)
{ {
......
...@@ -18,11 +18,14 @@ static void drop_pagecache_sb(struct super_block *sb, void *unused) ...@@ -18,11 +18,14 @@ static void drop_pagecache_sb(struct super_block *sb, void *unused)
spin_lock(&inode_lock); spin_lock(&inode_lock);
list_for_each_entry(inode, &sb->s_inodes, i_sb_list) { list_for_each_entry(inode, &sb->s_inodes, i_sb_list) {
if (inode->i_state & (I_FREEING|I_WILL_FREE|I_NEW)) spin_lock(&inode->i_lock);
continue; if ((inode->i_state & (I_FREEING|I_WILL_FREE|I_NEW)) ||
if (inode->i_mapping->nrpages == 0) (inode->i_mapping->nrpages == 0)) {
spin_unlock(&inode->i_lock);
continue; continue;
}
__iget(inode); __iget(inode);
spin_unlock(&inode->i_lock);
spin_unlock(&inode_lock); spin_unlock(&inode_lock);
invalidate_mapping_pages(inode->i_mapping, 0, -1); invalidate_mapping_pages(inode->i_mapping, 0, -1);
iput(toput_inode); iput(toput_inode);
......
...@@ -307,9 +307,11 @@ static void inode_wait_for_writeback(struct inode *inode) ...@@ -307,9 +307,11 @@ static void inode_wait_for_writeback(struct inode *inode)
wqh = bit_waitqueue(&inode->i_state, __I_SYNC); wqh = bit_waitqueue(&inode->i_state, __I_SYNC);
while (inode->i_state & I_SYNC) { while (inode->i_state & I_SYNC) {
spin_unlock(&inode->i_lock);
spin_unlock(&inode_lock); spin_unlock(&inode_lock);
__wait_on_bit(wqh, &wq, inode_wait, TASK_UNINTERRUPTIBLE); __wait_on_bit(wqh, &wq, inode_wait, TASK_UNINTERRUPTIBLE);
spin_lock(&inode_lock); spin_lock(&inode_lock);
spin_lock(&inode->i_lock);
} }
} }
...@@ -333,6 +335,7 @@ writeback_single_inode(struct inode *inode, struct writeback_control *wbc) ...@@ -333,6 +335,7 @@ writeback_single_inode(struct inode *inode, struct writeback_control *wbc)
unsigned dirty; unsigned dirty;
int ret; int ret;
spin_lock(&inode->i_lock);
if (!atomic_read(&inode->i_count)) if (!atomic_read(&inode->i_count))
WARN_ON(!(inode->i_state & (I_WILL_FREE|I_FREEING))); WARN_ON(!(inode->i_state & (I_WILL_FREE|I_FREEING)));
else else
...@@ -348,6 +351,7 @@ writeback_single_inode(struct inode *inode, struct writeback_control *wbc) ...@@ -348,6 +351,7 @@ writeback_single_inode(struct inode *inode, struct writeback_control *wbc)
* completed a full scan of b_io. * completed a full scan of b_io.
*/ */
if (wbc->sync_mode != WB_SYNC_ALL) { if (wbc->sync_mode != WB_SYNC_ALL) {
spin_unlock(&inode->i_lock);
requeue_io(inode); requeue_io(inode);
return 0; return 0;
} }
...@@ -363,6 +367,7 @@ writeback_single_inode(struct inode *inode, struct writeback_control *wbc) ...@@ -363,6 +367,7 @@ writeback_single_inode(struct inode *inode, struct writeback_control *wbc)
/* Set I_SYNC, reset I_DIRTY_PAGES */ /* Set I_SYNC, reset I_DIRTY_PAGES */
inode->i_state |= I_SYNC; inode->i_state |= I_SYNC;
inode->i_state &= ~I_DIRTY_PAGES; inode->i_state &= ~I_DIRTY_PAGES;
spin_unlock(&inode->i_lock);
spin_unlock(&inode_lock); spin_unlock(&inode_lock);
ret = do_writepages(mapping, wbc); ret = do_writepages(mapping, wbc);
...@@ -384,8 +389,10 @@ writeback_single_inode(struct inode *inode, struct writeback_control *wbc) ...@@ -384,8 +389,10 @@ writeback_single_inode(struct inode *inode, struct writeback_control *wbc)
* write_inode() * write_inode()
*/ */
spin_lock(&inode_lock); spin_lock(&inode_lock);
spin_lock(&inode->i_lock);
dirty = inode->i_state & I_DIRTY; dirty = inode->i_state & I_DIRTY;
inode->i_state &= ~(I_DIRTY_SYNC | I_DIRTY_DATASYNC); inode->i_state &= ~(I_DIRTY_SYNC | I_DIRTY_DATASYNC);
spin_unlock(&inode->i_lock);
spin_unlock(&inode_lock); spin_unlock(&inode_lock);
/* Don't write the inode if only I_DIRTY_PAGES was set */ /* Don't write the inode if only I_DIRTY_PAGES was set */
if (dirty & (I_DIRTY_SYNC | I_DIRTY_DATASYNC)) { if (dirty & (I_DIRTY_SYNC | I_DIRTY_DATASYNC)) {
...@@ -395,6 +402,7 @@ writeback_single_inode(struct inode *inode, struct writeback_control *wbc) ...@@ -395,6 +402,7 @@ writeback_single_inode(struct inode *inode, struct writeback_control *wbc)
} }
spin_lock(&inode_lock); spin_lock(&inode_lock);
spin_lock(&inode->i_lock);
inode->i_state &= ~I_SYNC; inode->i_state &= ~I_SYNC;
if (!(inode->i_state & I_FREEING)) { if (!(inode->i_state & I_FREEING)) {
if (mapping_tagged(mapping, PAGECACHE_TAG_DIRTY)) { if (mapping_tagged(mapping, PAGECACHE_TAG_DIRTY)) {
...@@ -436,6 +444,7 @@ writeback_single_inode(struct inode *inode, struct writeback_control *wbc) ...@@ -436,6 +444,7 @@ writeback_single_inode(struct inode *inode, struct writeback_control *wbc)
} }
} }
inode_sync_complete(inode); inode_sync_complete(inode);
spin_unlock(&inode->i_lock);
return ret; return ret;
} }
...@@ -506,7 +515,9 @@ static int writeback_sb_inodes(struct super_block *sb, struct bdi_writeback *wb, ...@@ -506,7 +515,9 @@ static int writeback_sb_inodes(struct super_block *sb, struct bdi_writeback *wb,
* kind does not need peridic writeout yet, and for the latter * kind does not need peridic writeout yet, and for the latter
* kind writeout is handled by the freer. * kind writeout is handled by the freer.
*/ */
spin_lock(&inode->i_lock);
if (inode->i_state & (I_NEW | I_FREEING | I_WILL_FREE)) { if (inode->i_state & (I_NEW | I_FREEING | I_WILL_FREE)) {
spin_unlock(&inode->i_lock);
requeue_io(inode); requeue_io(inode);
continue; continue;
} }
...@@ -515,10 +526,14 @@ static int writeback_sb_inodes(struct super_block *sb, struct bdi_writeback *wb, ...@@ -515,10 +526,14 @@ static int writeback_sb_inodes(struct super_block *sb, struct bdi_writeback *wb,
* Was this inode dirtied after sync_sb_inodes was called? * Was this inode dirtied after sync_sb_inodes was called?
* This keeps sync from extra jobs and livelock. * This keeps sync from extra jobs and livelock.
*/ */
if (inode_dirtied_after(inode, wbc->wb_start)) if (inode_dirtied_after(inode, wbc->wb_start)) {
spin_unlock(&inode->i_lock);
return 1; return 1;
}
__iget(inode); __iget(inode);
spin_unlock(&inode->i_lock);
pages_skipped = wbc->pages_skipped; pages_skipped = wbc->pages_skipped;
writeback_single_inode(inode, wbc); writeback_single_inode(inode, wbc);
if (wbc->pages_skipped != pages_skipped) { if (wbc->pages_skipped != pages_skipped) {
...@@ -724,7 +739,9 @@ static long wb_writeback(struct bdi_writeback *wb, ...@@ -724,7 +739,9 @@ static long wb_writeback(struct bdi_writeback *wb,
if (!list_empty(&wb->b_more_io)) { if (!list_empty(&wb->b_more_io)) {
inode = wb_inode(wb->b_more_io.prev); inode = wb_inode(wb->b_more_io.prev);
trace_wbc_writeback_wait(&wbc, wb->bdi); trace_wbc_writeback_wait(&wbc, wb->bdi);
spin_lock(&inode->i_lock);
inode_wait_for_writeback(inode); inode_wait_for_writeback(inode);
spin_unlock(&inode->i_lock);
} }
spin_unlock(&inode_lock); spin_unlock(&inode_lock);
} }
...@@ -1017,6 +1034,7 @@ void __mark_inode_dirty(struct inode *inode, int flags) ...@@ -1017,6 +1034,7 @@ void __mark_inode_dirty(struct inode *inode, int flags)
block_dump___mark_inode_dirty(inode); block_dump___mark_inode_dirty(inode);
spin_lock(&inode_lock); spin_lock(&inode_lock);
spin_lock(&inode->i_lock);
if ((inode->i_state & flags) != flags) { if ((inode->i_state & flags) != flags) {
const int was_dirty = inode->i_state & I_DIRTY; const int was_dirty = inode->i_state & I_DIRTY;
...@@ -1028,7 +1046,7 @@ void __mark_inode_dirty(struct inode *inode, int flags) ...@@ -1028,7 +1046,7 @@ void __mark_inode_dirty(struct inode *inode, int flags)
* superblock list, based upon its state. * superblock list, based upon its state.
*/ */
if (inode->i_state & I_SYNC) if (inode->i_state & I_SYNC)
goto out; goto out_unlock_inode;
/* /*
* Only add valid (hashed) inodes to the superblock's * Only add valid (hashed) inodes to the superblock's
...@@ -1036,11 +1054,12 @@ void __mark_inode_dirty(struct inode *inode, int flags) ...@@ -1036,11 +1054,12 @@ void __mark_inode_dirty(struct inode *inode, int flags)
*/ */
if (!S_ISBLK(inode->i_mode)) { if (!S_ISBLK(inode->i_mode)) {
if (inode_unhashed(inode)) if (inode_unhashed(inode))
goto out; goto out_unlock_inode;
} }
if (inode->i_state & I_FREEING) if (inode->i_state & I_FREEING)
goto out; goto out_unlock_inode;
spin_unlock(&inode->i_lock);
/* /*
* If the inode was already on b_dirty/b_io/b_more_io, don't * If the inode was already on b_dirty/b_io/b_more_io, don't
* reposition it (that would break b_dirty time-ordering). * reposition it (that would break b_dirty time-ordering).
...@@ -1065,7 +1084,10 @@ void __mark_inode_dirty(struct inode *inode, int flags) ...@@ -1065,7 +1084,10 @@ void __mark_inode_dirty(struct inode *inode, int flags)
inode->dirtied_when = jiffies; inode->dirtied_when = jiffies;
list_move(&inode->i_wb_list, &bdi->wb.b_dirty); list_move(&inode->i_wb_list, &bdi->wb.b_dirty);
} }
goto out;
} }
out_unlock_inode:
spin_unlock(&inode->i_lock);
out: out:
spin_unlock(&inode_lock); spin_unlock(&inode_lock);
...@@ -1111,14 +1133,16 @@ static void wait_sb_inodes(struct super_block *sb) ...@@ -1111,14 +1133,16 @@ static void wait_sb_inodes(struct super_block *sb)
* we still have to wait for that writeout. * we still have to wait for that writeout.
*/ */
list_for_each_entry(inode, &sb->s_inodes, i_sb_list) { list_for_each_entry(inode, &sb->s_inodes, i_sb_list) {
struct address_space *mapping; struct address_space *mapping = inode->i_mapping;
if (inode->i_state & (I_FREEING|I_WILL_FREE|I_NEW)) spin_lock(&inode->i_lock);
continue; if ((inode->i_state & (I_FREEING|I_WILL_FREE|I_NEW)) ||
mapping = inode->i_mapping; (mapping->nrpages == 0)) {
if (mapping->nrpages == 0) spin_unlock(&inode->i_lock);
continue; continue;
}
__iget(inode); __iget(inode);
spin_unlock(&inode->i_lock);
spin_unlock(&inode_lock); spin_unlock(&inode_lock);
/* /*
* We hold a reference to 'inode' so it couldn't have * We hold a reference to 'inode' so it couldn't have
......
This diff is collapsed.
...@@ -254,8 +254,11 @@ void fsnotify_unmount_inodes(struct list_head *list) ...@@ -254,8 +254,11 @@ void fsnotify_unmount_inodes(struct list_head *list)
* I_WILL_FREE, or I_NEW which is fine because by that point * I_WILL_FREE, or I_NEW which is fine because by that point
* the inode cannot have any associated watches. * the inode cannot have any associated watches.
*/ */
if (inode->i_state & (I_FREEING|I_WILL_FREE|I_NEW)) spin_lock(&inode->i_lock);
if (inode->i_state & (I_FREEING|I_WILL_FREE|I_NEW)) {
spin_unlock(&inode->i_lock);
continue; continue;
}
/* /*
* If i_count is zero, the inode cannot have any watches and * If i_count is zero, the inode cannot have any watches and
...@@ -263,8 +266,10 @@ void fsnotify_unmount_inodes(struct list_head *list) ...@@ -263,8 +266,10 @@ void fsnotify_unmount_inodes(struct list_head *list)
* evict all inodes with zero i_count from icache which is * evict all inodes with zero i_count from icache which is
* unnecessarily violent and may in fact be illegal to do. * unnecessarily violent and may in fact be illegal to do.
*/ */
if (!atomic_read(&inode->i_count)) if (!atomic_read(&inode->i_count)) {
spin_unlock(&inode->i_lock);
continue; continue;
}
need_iput_tmp = need_iput; need_iput_tmp = need_iput;
need_iput = NULL; need_iput = NULL;
...@@ -274,14 +279,18 @@ void fsnotify_unmount_inodes(struct list_head *list) ...@@ -274,14 +279,18 @@ void fsnotify_unmount_inodes(struct list_head *list)
__iget(inode); __iget(inode);
else else
need_iput_tmp = NULL; need_iput_tmp = NULL;
spin_unlock(&inode->i_lock);
/* In case the dropping of a reference would nuke next_i. */ /* In case the dropping of a reference would nuke next_i. */
if ((&next_i->i_sb_list != list) && if ((&next_i->i_sb_list != list) &&
atomic_read(&next_i->i_count) && atomic_read(&next_i->i_count)) {
!(next_i->i_state & (I_FREEING | I_WILL_FREE))) { spin_lock(&next_i->i_lock);
if (!(next_i->i_state & (I_FREEING | I_WILL_FREE))) {
__iget(next_i); __iget(next_i);
need_iput = next_i; need_iput = next_i;
} }
spin_unlock(&next_i->i_lock);
}
/* /*
* We can safely drop inode_lock here because we hold * We can safely drop inode_lock here because we hold
......
...@@ -902,18 +902,19 @@ static void add_dquot_ref(struct super_block *sb, int type) ...@@ -902,18 +902,19 @@ static void add_dquot_ref(struct super_block *sb, int type)
spin_lock(&inode_lock); spin_lock(&inode_lock);
list_for_each_entry(inode, &sb->s_inodes, i_sb_list) { list_for_each_entry(inode, &sb->s_inodes, i_sb_list) {
if (inode->i_state & (I_FREEING|I_WILL_FREE|I_NEW)) spin_lock(&inode->i_lock);
if ((inode->i_state & (I_FREEING|I_WILL_FREE|I_NEW)) ||
!atomic_read(&inode->i_writecount) ||
!dqinit_needed(inode, type)) {
spin_unlock(&inode->i_lock);
continue; continue;
}
#ifdef CONFIG_QUOTA_DEBUG #ifdef CONFIG_QUOTA_DEBUG
if (unlikely(inode_get_rsv_space(inode) > 0)) if (unlikely(inode_get_rsv_space(inode) > 0))
reserved = 1; reserved = 1;
#endif #endif
if (!atomic_read(&inode->i_writecount))
continue;
if (!dqinit_needed(inode, type))
continue;
__iget(inode); __iget(inode);
spin_unlock(&inode->i_lock);
spin_unlock(&inode_lock); spin_unlock(&inode_lock);
iput(old_inode); iput(old_inode);
......
...@@ -1647,7 +1647,7 @@ struct super_operations { ...@@ -1647,7 +1647,7 @@ struct super_operations {
}; };
/* /*
* Inode state bits. Protected by inode_lock. * Inode state bits. Protected by inode->i_lock
* *
* Three bits determine the dirty state of the inode, I_DIRTY_SYNC, * Three bits determine the dirty state of the inode, I_DIRTY_SYNC,
* I_DIRTY_DATASYNC and I_DIRTY_PAGES. * I_DIRTY_DATASYNC and I_DIRTY_PAGES.
......
...@@ -277,7 +277,7 @@ static inline int dquot_alloc_space(struct inode *inode, qsize_t nr) ...@@ -277,7 +277,7 @@ static inline int dquot_alloc_space(struct inode *inode, qsize_t nr)
/* /*
* Mark inode fully dirty. Since we are allocating blocks, inode * Mark inode fully dirty. Since we are allocating blocks, inode
* would become fully dirty soon anyway and it reportedly * would become fully dirty soon anyway and it reportedly
* reduces inode_lock contention. * reduces lock contention.
*/ */
mark_inode_dirty(inode); mark_inode_dirty(inode);
} }
......
...@@ -99,7 +99,9 @@ ...@@ -99,7 +99,9 @@
* ->private_lock (page_remove_rmap->set_page_dirty) * ->private_lock (page_remove_rmap->set_page_dirty)
* ->tree_lock (page_remove_rmap->set_page_dirty) * ->tree_lock (page_remove_rmap->set_page_dirty)
* ->inode_lock (page_remove_rmap->set_page_dirty) * ->inode_lock (page_remove_rmap->set_page_dirty)
* ->inode->i_lock (page_remove_rmap->set_page_dirty)
* ->inode_lock (zap_pte_range->set_page_dirty) * ->inode_lock (zap_pte_range->set_page_dirty)
* ->inode->i_lock (zap_pte_range->set_page_dirty)
* ->private_lock (zap_pte_range->__set_page_dirty_buffers) * ->private_lock (zap_pte_range->__set_page_dirty_buffers)
* *
* (code doesn't rely on that order, so you could switch it around) * (code doesn't rely on that order, so you could switch it around)
......
...@@ -32,6 +32,7 @@ ...@@ -32,6 +32,7 @@
* mmlist_lock (in mmput, drain_mmlist and others) * mmlist_lock (in mmput, drain_mmlist and others)
* mapping->private_lock (in __set_page_dirty_buffers) * mapping->private_lock (in __set_page_dirty_buffers)
* inode_lock (in set_page_dirty's __mark_inode_dirty) * inode_lock (in set_page_dirty's __mark_inode_dirty)
* inode->i_lock (in set_page_dirty's __mark_inode_dirty)
* sb_lock (within inode_lock in fs/fs-writeback.c) * sb_lock (within inode_lock in fs/fs-writeback.c)
* mapping->tree_lock (widely used, in set_page_dirty, * mapping->tree_lock (widely used, in set_page_dirty,
* in arch-dependent flush_dcache_mmap_lock, * in arch-dependent flush_dcache_mmap_lock,
......
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