fs: only specify I_DIRTY_TIME when needed in generic_update_time()

generic_update_time() always passes I_DIRTY_TIME to
__mark_inode_dirty(), which doesn't really make sense because (a)
generic_update_time() might be asked to do only an i_version update, not
also a timestamps update; and (b) I_DIRTY_TIME is only supposed to be
set in i_state if the filesystem has lazytime enabled, so using it
unconditionally in generic_update_time() is inconsistent.

As a result there is a weird edge case where if only an i_version update
was requested (not also a timestamps update) but it is no longer needed
(i.e. inode_maybe_inc_iversion() returns false), then I_DIRTY_TIME will
be set in i_state even if the filesystem isn't mounted with lazytime.

Fix this by only passing I_DIRTY_TIME to __mark_inode_dirty() if the
timestamps were updated and the filesystem has lazytime enabled.

Link: https://lore.kernel.org/r/20210112190253.64307-4-ebiggers@kernel.org
Reviewed-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Jan Kara <jack@suse.cz>
Signed-off-by: Eric Biggers <ebiggers@google.com>
Signed-off-by: Jan Kara <jack@suse.cz>
This commit is contained in:
Eric Biggers 2021-01-12 11:02:45 -08:00 committed by Jan Kara
parent 1e9d63331f
commit e20b14db05

View File

@ -1743,24 +1743,26 @@ static int relatime_need_update(struct vfsmount *mnt, struct inode *inode,
int generic_update_time(struct inode *inode, struct timespec64 *time, int flags)
{
int iflags = I_DIRTY_TIME;
bool dirty = false;
int dirty_flags = 0;
if (flags & S_ATIME)
inode->i_atime = *time;
if (flags & S_VERSION)
dirty = inode_maybe_inc_iversion(inode, false);
if (flags & S_CTIME)
inode->i_ctime = *time;
if (flags & S_MTIME)
inode->i_mtime = *time;
if ((flags & (S_ATIME | S_CTIME | S_MTIME)) &&
!(inode->i_sb->s_flags & SB_LAZYTIME))
dirty = true;
if (flags & (S_ATIME | S_CTIME | S_MTIME)) {
if (flags & S_ATIME)
inode->i_atime = *time;
if (flags & S_CTIME)
inode->i_ctime = *time;
if (flags & S_MTIME)
inode->i_mtime = *time;
if (dirty)
iflags |= I_DIRTY_SYNC;
__mark_inode_dirty(inode, iflags);
if (inode->i_sb->s_flags & SB_LAZYTIME)
dirty_flags |= I_DIRTY_TIME;
else
dirty_flags |= I_DIRTY_SYNC;
}
if ((flags & S_VERSION) && inode_maybe_inc_iversion(inode, false))
dirty_flags |= I_DIRTY_SYNC;
__mark_inode_dirty(inode, dirty_flags);
return 0;
}
EXPORT_SYMBOL(generic_update_time);