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authorJoern Engel <joern@wohnheim.fh-wedel.de>2007-10-16 23:30:44 -0700
committerLinus Torvalds <torvalds@woody.linux-foundation.org>2007-10-17 08:43:02 -0700
commit1c0eeaf5698597146ed9b873e2f9e0961edcf0f9 (patch)
tree5265eac8437e8ce517a62db8fe2bd99db5b7019b /fs/fs-writeback.c
parent2e6883bdf49abd0e7f0d9b6297fc3be7ebb2250b (diff)
downloadlwn-1c0eeaf5698597146ed9b873e2f9e0961edcf0f9.tar.gz
lwn-1c0eeaf5698597146ed9b873e2f9e0961edcf0f9.zip
introduce I_SYNC
I_LOCK was used for several unrelated purposes, which caused deadlock situations in certain filesystems as a side effect. One of the purposes now uses the new I_SYNC bit. Also document the various bits and change their order from historical to logical. [bunk@stusta.de: make fs/inode.c:wake_up_inode() static] Signed-off-by: Joern Engel <joern@wohnheim.fh-wedel.de> Cc: Dave Kleikamp <shaggy@linux.vnet.ibm.com> Cc: David Chinner <dgc@sgi.com> Cc: Anton Altaparmakov <aia21@cam.ac.uk> Cc: Al Viro <viro@ftp.linux.org.uk> Cc: Christoph Hellwig <hch@infradead.org> Signed-off-by: Adrian Bunk <bunk@stusta.de> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Diffstat (limited to 'fs/fs-writeback.c')
-rw-r--r--fs/fs-writeback.c39
1 files changed, 24 insertions, 15 deletions
diff --git a/fs/fs-writeback.c b/fs/fs-writeback.c
index 71c158ac60a3..686734ff973d 100644
--- a/fs/fs-writeback.c
+++ b/fs/fs-writeback.c
@@ -100,11 +100,11 @@ void __mark_inode_dirty(struct inode *inode, int flags)
inode->i_state |= flags;
/*
- * If the inode is locked, just update its dirty state.
+ * If the inode is being synced, just update its dirty state.
* The unlocker will place the inode on the appropriate
* superblock list, based upon its state.
*/
- if (inode->i_state & I_LOCK)
+ if (inode->i_state & I_SYNC)
goto out;
/*
@@ -172,6 +172,15 @@ static void requeue_io(struct inode *inode)
list_move(&inode->i_list, &inode->i_sb->s_more_io);
}
+static void inode_sync_complete(struct inode *inode)
+{
+ /*
+ * Prevent speculative execution through spin_unlock(&inode_lock);
+ */
+ smp_mb();
+ wake_up_bit(&inode->i_state, __I_SYNC);
+}
+
/*
* Move expired dirty inodes from @delaying_queue to @dispatch_queue.
*/
@@ -225,11 +234,11 @@ __sync_single_inode(struct inode *inode, struct writeback_control *wbc)
int wait = wbc->sync_mode == WB_SYNC_ALL;
int ret;
- BUG_ON(inode->i_state & I_LOCK);
+ BUG_ON(inode->i_state & I_SYNC);
- /* Set I_LOCK, reset I_DIRTY */
+ /* Set I_SYNC, reset I_DIRTY */
dirty = inode->i_state & I_DIRTY;
- inode->i_state |= I_LOCK;
+ inode->i_state |= I_SYNC;
inode->i_state &= ~I_DIRTY;
spin_unlock(&inode_lock);
@@ -250,7 +259,7 @@ __sync_single_inode(struct inode *inode, struct writeback_control *wbc)
}
spin_lock(&inode_lock);
- inode->i_state &= ~I_LOCK;
+ inode->i_state &= ~I_SYNC;
if (!(inode->i_state & I_FREEING)) {
if (!(inode->i_state & I_DIRTY) &&
mapping_tagged(mapping, PAGECACHE_TAG_DIRTY)) {
@@ -305,7 +314,7 @@ __sync_single_inode(struct inode *inode, struct writeback_control *wbc)
list_move(&inode->i_list, &inode_unused);
}
}
- wake_up_inode(inode);
+ inode_sync_complete(inode);
return ret;
}
@@ -324,7 +333,7 @@ __writeback_single_inode(struct inode *inode, struct writeback_control *wbc)
else
WARN_ON(inode->i_state & I_WILL_FREE);
- if ((wbc->sync_mode != WB_SYNC_ALL) && (inode->i_state & I_LOCK)) {
+ if ((wbc->sync_mode != WB_SYNC_ALL) && (inode->i_state & I_SYNC)) {
struct address_space *mapping = inode->i_mapping;
int ret;
@@ -350,16 +359,16 @@ __writeback_single_inode(struct inode *inode, struct writeback_control *wbc)
/*
* It's a data-integrity sync. We must wait.
*/
- if (inode->i_state & I_LOCK) {
- DEFINE_WAIT_BIT(wq, &inode->i_state, __I_LOCK);
+ if (inode->i_state & I_SYNC) {
+ DEFINE_WAIT_BIT(wq, &inode->i_state, __I_SYNC);
- wqh = bit_waitqueue(&inode->i_state, __I_LOCK);
+ wqh = bit_waitqueue(&inode->i_state, __I_SYNC);
do {
spin_unlock(&inode_lock);
__wait_on_bit(wqh, &wq, inode_wait,
TASK_UNINTERRUPTIBLE);
spin_lock(&inode_lock);
- } while (inode->i_state & I_LOCK);
+ } while (inode->i_state & I_SYNC);
}
return __sync_single_inode(inode, wbc);
}
@@ -392,7 +401,7 @@ __writeback_single_inode(struct inode *inode, struct writeback_control *wbc)
* The inodes to be written are parked on sb->s_io. They are moved back onto
* sb->s_dirty as they are selected for writing. This way, none can be missed
* on the writer throttling path, and we get decent balancing between many
- * throttled threads: we don't want them all piling up on __wait_on_inode.
+ * throttled threads: we don't want them all piling up on inode_sync_wait.
*/
static void
sync_sb_inodes(struct super_block *sb, struct writeback_control *wbc)
@@ -661,7 +670,7 @@ int write_inode_now(struct inode *inode, int sync)
ret = __writeback_single_inode(inode, &wbc);
spin_unlock(&inode_lock);
if (sync)
- wait_on_inode(inode);
+ inode_sync_wait(inode);
return ret;
}
EXPORT_SYMBOL(write_inode_now);
@@ -736,7 +745,7 @@ int generic_osync_inode(struct inode *inode, struct address_space *mapping, int
err = err2;
}
else
- wait_on_inode(inode);
+ inode_sync_wait(inode);
return err;
}