[PATCH v3 11/11] ext4: simplify i_state checks in __ext4_update_other_inode_time()

Eric Biggers
2021-01-12T19:05:33Z

Since I_DIRTY_TIME and I_DIRTY_INODE are mutually exclusive in i_state,
there's no need to check for I_DIRTY_TIME && !I_DIRTY_INODE. Just check
for I_DIRTY_TIME.

Also introduce a helper function in include/linux/fs.h to do this check.

Signed-off-by: Eric Biggers <ebiggers@google.com>
---
fs/ext4/inode.c | 8 ++------
include/linux/fs.h | 15 +++++++++++++++
2 files changed, 17 insertions(+), 6 deletions(-)

diff --git a/fs/ext4/inode.c b/fs/ext4/inode.c
index 4cc6c7834312f..d809a06b6ef7f 100644
--- a/fs/ext4/inode.c
+++ b/fs/ext4/inode.c
@@ -4961,15 +4961,11 @@ static void __ext4_update_other_inode_time(struct super_block *sb,
if (!inode)
return;

- if ((inode->i_state & (I_FREEING | I_WILL_FREE | I_NEW |
- I_DIRTY_INODE)) ||
- ((inode->i_state & I_DIRTY_TIME) == 0))
+ if (!inode_is_dirtytime_only(inode))
return;

spin_lock(&inode->i_lock);
- if (((inode->i_state & (I_FREEING | I_WILL_FREE | I_NEW |
- I_DIRTY_INODE)) == 0) &&
- (inode->i_state & I_DIRTY_TIME)) {
+ if (inode_is_dirtytime_only(inode)) {
struct ext4_inode_info *ei = EXT4_I(inode);

inode->i_state &= ~I_DIRTY_TIME;
diff --git a/include/linux/fs.h b/include/linux/fs.h
index 45a0303b2aeb6..de0c789104c26 100644
--- a/include/linux/fs.h
+++ b/include/linux/fs.h
@@ -2194,6 +2194,21 @@ static inline void mark_inode_dirty_sync(struct inode *inode)
__mark_inode_dirty(inode, I_DIRTY_SYNC);
}

+/*
+ * Returns true if the given inode itself only has dirty timestamps (its pages
+ * may still be dirty) and isn't currently being allocated or freed.
+ * Filesystems should call this if when writing an inode when lazytime is
+ * enabled, they want to opportunistically write the timestamps of other inodes
+ * located very nearby on-disk, e.g. in the same inode block. This returns true
+ * if the given inode is in need of such an opportunistic update. Requires
+ * i_lock, or at least later re-checking under i_lock.
+ */
+static inline bool inode_is_dirtytime_only(struct inode *inode)
+{
+ return (inode->i_state & (I_DIRTY_TIME | I_NEW |
+ I_FREEING | I_WILL_FREE)) == I_DIRTY_TIME;
+}
+
extern void inc_nlink(struct inode *inode);
extern void drop_nlink(struct inode *inode);
extern void clear_nlink(struct inode *inode);
--
2.30.0