[PATCH] writeback: avoid double-writing the inode on a lazytime expiration

[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index]

 



In the case that an inode has dirty timestamp for longer than the
lazytime expiration timeout (or if all such inodes are being flushed
out due to a sync or syncfs system call), we need to inform the file
system that the inode is dirty so that the inode's timestamps can be
copied out to the on-disk data structures.  That's because if the file
system supports lazytime, it will have ignored the dirty_inode(inode,
I_DIRTY_TIME) notification when the timestamp was modified in memory.q

Previously, this was accomplished by calling mark_inode_dirty_sync(),
but that has the unfortunate side effect of also putting the inode the
writeback list, and that's not necessary in this case, since we will
immediately call write_inode() afterwards.

Eric Biggers noticed that this was causing problems for fscrypt after
the key was removed[1].

[1] https://lore.kernel.org/r/20200306004555.GB225345@xxxxxxxxx

Reported-by: Eric Biggers <ebiggers@xxxxxxxxxx>
Signed-off-by: Theodore Ts'o <tytso@xxxxxxx>
---
 fs/fs-writeback.c | 5 +++--
 1 file changed, 3 insertions(+), 2 deletions(-)

diff --git a/fs/fs-writeback.c b/fs/fs-writeback.c
index 76ac9c7d32ec..32101349ba97 100644
--- a/fs/fs-writeback.c
+++ b/fs/fs-writeback.c
@@ -1504,8 +1504,9 @@ __writeback_single_inode(struct inode *inode, struct writeback_control *wbc)
 
 	spin_unlock(&inode->i_lock);
 
-	if (dirty & I_DIRTY_TIME)
-		mark_inode_dirty_sync(inode);
+	/* This was a lazytime expiration; we need to tell the file system */
+	if (dirty & I_DIRTY_TIME_EXPIRED && inode->i_sb->s_op->dirty_inode)
+		inode->i_sb->s_op->dirty_inode(inode, I_DIRTY_TIME_EXPIRED);
 	/* Don't write the inode if only I_DIRTY_PAGES was set */
 	if (dirty & ~I_DIRTY_PAGES) {
 		int err = write_inode(inode, wbc);
-- 
2.24.1




[Index of Archives]     [Reiser Filesystem Development]     [Ceph FS]     [Kernel Newbies]     [Security]     [Netfilter]     [Bugtraq]     [Linux FS]     [Yosemite National Park]     [MIPS Linux]     [ARM Linux]     [Linux Security]     [Linux RAID]     [Samba]     [Device Mapper]     [Linux Media]

  Powered by Linux