fs: add icount_read_once() and stop open-coding ->i_count loads

Similarly to inode_state_read_once(), it makes the caller spell out
they acknowledge instability of the returned value.

Signed-off-by: Mateusz Guzik <mjguzik@gmail.com>
Link: https://patch.msgid.link/20260421182538.1215894-2-mjguzik@gmail.com
Reviewed-by: Jan Kara <jack@suse.cz>
Signed-off-by: Christian Brauner <brauner@kernel.org>
This commit is contained in:
Mateusz Guzik 2026-04-21 20:25:36 +02:00 committed by Christian Brauner
parent 254f49634e
commit 769e143b11
No known key found for this signature in database
GPG Key ID: 91C61BC06578DCA2
14 changed files with 33 additions and 20 deletions

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@ -1430,7 +1430,7 @@ static int spufs_mfc_open(struct inode *inode, struct file *file)
if (ctx->owner != current->mm)
return -EINVAL;
if (icount_read(inode) != 1)
if (icount_read_once(inode) != 1)
return -EBUSY;
mutex_lock(&ctx->mapping_lock);

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@ -4745,7 +4745,7 @@ static void btrfs_prune_dentries(struct btrfs_root *root)
inode = btrfs_find_first_inode(root, min_ino);
while (inode) {
if (icount_read(&inode->vfs_inode) > 1)
if (icount_read_once(&inode->vfs_inode) > 1)
d_prune_aliases(&inode->vfs_inode);
min_ino = btrfs_ino(inode) + 1;

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@ -2267,7 +2267,7 @@ static int trim_caps_cb(struct inode *inode, int mds, void *arg)
int count;
dput(dentry);
d_prune_aliases(inode);
count = icount_read(inode);
count = icount_read_once(inode);
if (count == 1)
(*remaining)--;
doutc(cl, "%p %llx.%llx cap %p pruned, count now %d\n",

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@ -252,10 +252,10 @@ void ext4_free_inode(handle_t *handle, struct inode *inode)
"nonexistent device\n", __func__, __LINE__);
return;
}
if (icount_read(inode) > 1) {
if (icount_read_once(inode) > 1) {
ext4_msg(sb, KERN_ERR, "%s:%d: inode #%llu: count=%d",
__func__, __LINE__, inode->i_ino,
icount_read(inode));
icount_read_once(inode));
return;
}
if (inode->i_nlink) {

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@ -184,7 +184,7 @@ void hpfs_write_inode(struct inode *i)
struct hpfs_inode_info *hpfs_inode = hpfs_i(i);
struct inode *parent;
if (i->i_ino == hpfs_sb(i->i_sb)->sb_root) return;
if (hpfs_inode->i_rddir_off && !icount_read(i)) {
if (hpfs_inode->i_rddir_off && !icount_read_once(i)) {
if (*hpfs_inode->i_rddir_off)
pr_err("write_inode: some position still there\n");
kfree(hpfs_inode->i_rddir_off);

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@ -902,7 +902,7 @@ void evict_inodes(struct super_block *sb)
again:
spin_lock(&sb->s_inode_list_lock);
list_for_each_entry(inode, &sb->s_inodes, i_sb_list) {
if (icount_read(inode))
if (icount_read_once(inode))
continue;
spin_lock(&inode->i_lock);
@ -1920,7 +1920,7 @@ static void iput_final(struct inode *inode)
int drop;
WARN_ON(inode_state_read(inode) & I_NEW);
VFS_BUG_ON_INODE(atomic_read(&inode->i_count) != 0, inode);
VFS_BUG_ON_INODE(icount_read(inode) != 0, inode);
if (op->drop_inode)
drop = op->drop_inode(inode);
@ -1939,7 +1939,7 @@ static void iput_final(struct inode *inode)
* Re-check ->i_count in case the ->drop_inode() hooks played games.
* Note we only execute this if the verdict was to drop the inode.
*/
VFS_BUG_ON_INODE(atomic_read(&inode->i_count) != 0, inode);
VFS_BUG_ON_INODE(icount_read(inode) != 0, inode);
if (drop) {
inode_state_set(inode, I_FREEING);
@ -1983,7 +1983,7 @@ void iput(struct inode *inode)
* equal to one, then two CPUs racing to further drop it can both
* conclude it's fine.
*/
VFS_BUG_ON_INODE(atomic_read(&inode->i_count) < 1, inode);
VFS_BUG_ON_INODE(icount_read_once(inode) < 1, inode);
if (atomic_add_unless(&inode->i_count, -1, 1))
return;
@ -2017,7 +2017,7 @@ EXPORT_SYMBOL(iput);
void iput_not_last(struct inode *inode)
{
VFS_BUG_ON_INODE(inode_state_read_once(inode) & (I_FREEING | I_CLEAR), inode);
VFS_BUG_ON_INODE(atomic_read(&inode->i_count) < 2, inode);
VFS_BUG_ON_INODE(icount_read_once(inode) < 2, inode);
WARN_ON(atomic_sub_return(1, &inode->i_count) == 0);
}
@ -3040,7 +3040,7 @@ void dump_inode(struct inode *inode, const char *reason)
}
state = inode_state_read_once(inode);
count = atomic_read(&inode->i_count);
count = icount_read_once(inode);
if (!sb ||
get_kernel_nofault(s_type, &sb->s_type) || !s_type ||

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@ -608,7 +608,7 @@ nfs_fhget(struct super_block *sb, struct nfs_fh *fh, struct nfs_fattr *fattr)
inode->i_sb->s_id,
(unsigned long long)NFS_FILEID(inode),
nfs_display_fhandle_hash(fh),
icount_read(inode));
icount_read_once(inode));
out:
return inode;
@ -2255,7 +2255,7 @@ static int nfs_update_inode(struct inode *inode, struct nfs_fattr *fattr)
dfprintk(VFS, "NFS: %s(%s/%llu fh_crc=0x%08x ct=%d info=0x%llx)\n",
__func__, inode->i_sb->s_id, inode->i_ino,
nfs_display_fhandle_hash(NFS_FH(inode)),
icount_read(inode), fattr->valid);
icount_read_once(inode), fattr->valid);
if (!(fattr->valid & NFS_ATTR_FATTR_FILEID)) {
/* Only a mounted-on-fileid? Just exit */

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@ -2843,7 +2843,7 @@ int cifs_revalidate_dentry_attr(struct dentry *dentry)
}
cifs_dbg(FYI, "Update attributes: %s inode 0x%p count %d dentry: 0x%p d_time %ld jiffies %ld\n",
full_path, inode, icount_read(inode),
full_path, inode, icount_read_once(inode),
dentry, cifs_get_time(dentry), jiffies);
again:

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@ -358,7 +358,7 @@ static void ubifs_evict_inode(struct inode *inode)
goto out;
dbg_gen("inode %llu, mode %#x", inode->i_ino, (int)inode->i_mode);
ubifs_assert(c, !icount_read(inode));
ubifs_assert(c, !icount_read_once(inode));
truncate_inode_pages_final(&inode->i_data);

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@ -1046,7 +1046,7 @@ xfs_itruncate_extents_flags(
int error = 0;
xfs_assert_ilocked(ip, XFS_ILOCK_EXCL);
if (icount_read(VFS_I(ip)))
if (icount_read_once(VFS_I(ip)))
xfs_assert_ilocked(ip, XFS_IOLOCK_EXCL);
if (whichfork == XFS_DATA_FORK)
ASSERT(new_size <= XFS_ISIZE(ip));

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@ -1158,7 +1158,7 @@ DECLARE_EVENT_CLASS(xfs_iref_class,
TP_fast_assign(
__entry->dev = VFS_I(ip)->i_sb->s_dev;
__entry->ino = ip->i_ino;
__entry->count = icount_read(VFS_I(ip));
__entry->count = icount_read_once(VFS_I(ip));
__entry->pincount = atomic_read(&ip->i_pincount);
__entry->iflags = ip->i_flags;
__entry->caller_ip = caller_ip;

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@ -2218,8 +2218,21 @@ static inline void mark_inode_dirty_sync(struct inode *inode)
__mark_inode_dirty(inode, I_DIRTY_SYNC);
}
/*
* returns the refcount on the inode. it can change arbitrarily.
*/
static inline int icount_read_once(const struct inode *inode)
{
return atomic_read(&inode->i_count);
}
/*
* returns the refcount on the inode. The lock guarantees no new references
* are added, but references can be dropped as long as the result is > 0.
*/
static inline int icount_read(const struct inode *inode)
{
lockdep_assert_held(&inode->i_lock);
return atomic_read(&inode->i_count);
}

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@ -190,7 +190,7 @@ TRACE_EVENT(generic_add_lease,
__entry->i_ino = inode->i_ino;
__entry->wcount = atomic_read(&inode->i_writecount);
__entry->rcount = atomic_read(&inode->i_readcount);
__entry->icount = icount_read(inode);
__entry->icount = icount_read_once(inode);
__entry->owner = fl->c.flc_owner;
__entry->flags = fl->c.flc_flags;
__entry->type = fl->c.flc_type;

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@ -1278,7 +1278,7 @@ static void hook_sb_delete(struct super_block *const sb)
struct landlock_object *object;
/* Only handles referenced inodes. */
if (!icount_read(inode))
if (!icount_read_once(inode))
continue;
/*