Re: [PATCH v2 26/54] fs: use igrab in insert_inode_locked
From: Christian Brauner <brauner@kernel.org>
Date: 2025-08-28 12:15:51
Also in:
linux-btrfs, linux-fsdevel, linux-xfs
On Tue, Aug 26, 2025 at 11:39:26AM -0400, Josef Bacik wrote:
quoted hunk ↗ jump to hunk
Follow the same pattern in find_inode*. Instead of checking for I_WILL_FREE|I_FREEING simply call igrab() and if it succeeds we're done. Signed-off-by: Josef Bacik <josef@toxicpanda.com> --- fs/inode.c | 8 +++----- 1 file changed, 3 insertions(+), 5 deletions(-)diff --git a/fs/inode.c b/fs/inode.c index 8ae9ed9605ef..d34da95a3295 100644 --- a/fs/inode.c +++ b/fs/inode.c@@ -1883,11 +1883,8 @@ int insert_inode_locked(struct inode *inode) continue; if (old->i_sb != sb) continue; - spin_lock(&old->i_lock); - if (old->i_state & (I_FREEING|I_WILL_FREE)) { - spin_unlock(&old->i_lock); + if (!igrab(old)) continue; - } break; } if (likely(!old)) {@@ -1899,12 +1896,13 @@ int insert_inode_locked(struct inode *inode) spin_unlock(&inode_hash_lock); return 0; } + spin_lock(&old->i_lock); if (unlikely(old->i_state & I_CREATING)) { spin_unlock(&old->i_lock); spin_unlock(&inode_hash_lock); + iput(old); return -EBUSY; } - __iget(old); spin_unlock(&old->i_lock); spin_unlock(&inode_hash_lock); wait_on_inode(old);-- 2.49.0
So looking at the function in full context:
int insert_inode_locked(struct inode *inode)
{
struct super_block *sb = inode->i_sb;
ino_t ino = inode->i_ino;
struct hlist_head *head = inode_hashtable + hash(sb, ino);
while (1) {
struct inode *old = NULL;
spin_lock(&inode_hash_lock);
hlist_for_each_entry(old, head, i_hash) {
if (old->i_ino != ino)
continue;
if (old->i_sb != sb)
continue;
if (!igrab(old))
continue;
break;
}
if (likely(!old)) {
spin_lock(&inode->i_lock);
iobj_get(inode);
Sorry, this is probably me being confused.
Say we allocated a new inode then we've definitely went through
inode_init_always() and so i_obj_count == i_count == 1.
Then we insert it into the hash table. For that we only take an
i_obj_count but no i_count bringing it to 2.
So for the hashlist we only deal with i_obj_count.
Is that documented somewhere? I probably just read over it.