Currently the I_DIRTY_TIME will never get set if the inode already has
I_DIRTY_INODE with assumption that it supersedes I_DIRTY_TIME. That's
true, however ext4 will only update the on-disk inode in
->dirty_inode(), not on actual writeback. As a result if the inode
already has I_DIRTY_INODE state by the time we get to
__mark_inode_dirty() only with I_DIRTY_TIME, the time was already filled
into on-disk inode and will not get updated until the next I_DIRTY_INODE
update, which might never come if we crash or get a power failure.
The problem can be reproduced on ext4 by running xfstest generic/622
with -o iversion mount option. Fix it by setting I_DIRTY_TIME even if
the inode already has I_DIRTY_INODE.
Also clear the I_DIRTY_TIME after ->dirty_inode() otherwise it may never
get cleared.
Signed-off-by: Lukas Czerner <lczerner@xxxxxxxxxx>
---
fs/fs-writeback.c | 18 +++++++++++++++---
1 file changed, 15 insertions(+), 3 deletions(-)
diff --git a/fs/fs-writeback.c b/fs/fs-writeback.c
index 05221366a16d..174f01e6b912 100644
--- a/fs/fs-writeback.c
+++ b/fs/fs-writeback.c
@@ -2383,6 +2383,11 @@ void __mark_inode_dirty(struct inode *inode, int flags)
/* I_DIRTY_INODE supersedes I_DIRTY_TIME. */
flags &= ~I_DIRTY_TIME;
+ if (inode->i_state & I_DIRTY_TIME) {
+ spin_lock(&inode->i_lock);
+ inode->i_state &= ~I_DIRTY_TIME;
+ spin_unlock(&inode->i_lock);
+ }
} else {
/*
* Else it's either I_DIRTY_PAGES, I_DIRTY_TIME, or nothing.
@@ -2399,13 +2404,20 @@ void __mark_inode_dirty(struct inode *inode, int flags)
*/
smp_mb();
- if (((inode->i_state & flags) == flags) ||
- (dirtytime && (inode->i_state & I_DIRTY_INODE)))
+ if ((inode->i_state & flags) == flags)
return;
spin_lock(&inode->i_lock);
- if (dirtytime && (inode->i_state & I_DIRTY_INODE))
+ if (dirtytime && (inode->i_state & I_DIRTY_INODE)) {
+ /*
+ * We've got a new lazytime update. Make sure it's recorded in
+ * i_state, because the time might have already got updated in
+ * ->dirty_inode() and will not get updated until next
+ * I_DIRTY_INODE update.
+ */
+ inode->i_state |= I_DIRTY_TIME;
goto out_unlock_inode;
+ }
if ((inode->i_state & flags) != flags) {
const int was_dirty = inode->i_state & I_DIRTY;
--
2.35.3
