Merge tag 'vfs-6.10-rc8.fixes' of git://git.kernel.org/pub/scm/linux/kernel/git/vfs/vfs

Pull vfs fixes from Christian Brauner:
 "cachefiles:

   - Export an existing and add a new cachefile helper to be used in
     filesystems to fix reference count bugs

   - Use the newly added fscache_ty_get_volume() helper to get a
     reference count on an fscache_volume to handle volumes that are
     about to be removed cleanly

   - After withdrawing a fscache_cache via FSCACHE_CACHE_IS_WITHDRAWN
     wait for all ongoing cookie lookups to complete and for the object
     count to reach zero

   - Propagate errors from vfs_getxattr() to avoid an infinite loop in
     cachefiles_check_volume_xattr() because it keeps seeing ESTALE

   - Don't send new requests when an object is dropped by raising
     CACHEFILES_ONDEMAND_OJBSTATE_DROPPING

   - Cancel all requests for an object that is about to be dropped

   - Wait for the ondemand_boject_worker to finish before dropping a
     cachefiles object to prevent use-after-free

   - Use cyclic allocation for message ids to better handle id recycling

   - Add missing lock protection when iterating through the xarray when
     polling

  netfs:

   - Use standard logging helpers for debug logging

  VFS:

   - Fix potential use-after-free in file locks during
     trace_posix_lock_inode(). The tracepoint could fire while another
     task raced it and freed the lock that was requested to be traced

   - Only increment the nr_dentry_negative counter for dentries that are
     present on the superblock LRU. Currently, DCACHE_LRU_LIST list is
     used to detect this case. However, the flag is also raised in
     combination with DCACHE_SHRINK_LIST to indicate that dentry->d_lru
     is used. So checking only DCACHE_LRU_LIST will lead to wrong
     nr_dentry_negative count. Fix the check to not count dentries that
     are on a shrink related list

  Misc:

   - hfsplus: fix an uninitialized value issue in copy_name

   - minix: fix minixfs_rename with HIGHMEM. It still uses kunmap() even
     though we switched it to kmap_local_page() a while ago"

* tag 'vfs-6.10-rc8.fixes' of git://git.kernel.org/pub/scm/linux/kernel/git/vfs/vfs:
  minixfs: Fix minixfs_rename with HIGHMEM
  hfsplus: fix uninit-value in copy_name
  vfs: don't mod negative dentry count when on shrinker list
  filelock: fix potential use-after-free in posix_lock_inode
  cachefiles: add missing lock protection when polling
  cachefiles: cyclic allocation of msg_id to avoid reuse
  cachefiles: wait for ondemand_object_worker to finish when dropping object
  cachefiles: cancel all requests for the object that is being dropped
  cachefiles: stop sending new request when dropping object
  cachefiles: propagate errors from vfs_getxattr() to avoid infinite loop
  cachefiles: fix slab-use-after-free in cachefiles_withdraw_cookie()
  cachefiles: fix slab-use-after-free in fscache_withdraw_volume()
  netfs, fscache: export fscache_put_volume() and add fscache_try_get_volume()
  netfs: Switch debug logging to pr_debug()

1 files changed, 9 insertions, 3 deletions

diff --git a/fs/dcache.c b/fs/dcache.c
index d58dc9e58f3b..4c144519aa70 100644
--- a/fs/dcache.c
+++ b/fs/dcache.c
@@ -355,7 +355,11 @@ static inline void __d_clear_type_and_inode(struct dentry *dentry)
 	flags &= ~DCACHE_ENTRY_TYPE;
 	WRITE_ONCE(dentry->d_flags, flags);
 	dentry->d_inode = NULL;
-	if (flags & DCACHE_LRU_LIST)
+	/*
+	 * The negative counter only tracks dentries on the LRU. Don't inc if
+	 * d_lru is on another list.
+	 */
+	if ((flags & (DCACHE_LRU_LIST|DCACHE_SHRINK_LIST)) == DCACHE_LRU_LIST)
 		this_cpu_inc(nr_dentry_negative);
 }
 
@@ -1844,9 +1848,11 @@ static void __d_instantiate(struct dentry *dentry, struct inode *inode)
 
 	spin_lock(&dentry->d_lock);
 	/*
-	 * Decrement negative dentry count if it was in the LRU list.
+	 * The negative counter only tracks dentries on the LRU. Don't dec if
+	 * d_lru is on another list.
 	 */
-	if (dentry->d_flags & DCACHE_LRU_LIST)
+	if ((dentry->d_flags &
+	     (DCACHE_LRU_LIST|DCACHE_SHRINK_LIST)) == DCACHE_LRU_LIST)
 		this_cpu_dec(nr_dentry_negative);
 	hlist_add_head(&dentry->d_u.d_alias, &inode->i_dentry);
 	raw_write_seqcount_begin(&dentry->d_seq);