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| author | Linus Torvalds <torvalds@linux-foundation.org> | 2018-02-01 04:15:23 +0100 |
|---|---|---|
| committer | Linus Torvalds <torvalds@linux-foundation.org> | 2018-02-01 04:15:23 +0100 |
| commit | dc1efc3cfaf5e16870a9a7b1b903dcf6e3ef15e8 (patch) | |
| tree | c020453fcfc517dee72526fffc8be13f101951c0 | |
| parent | Merge branch 'akpm' (patches from Andrew) (diff) | |
| parent | VFS: close race between getcwd() and d_move() (diff) | |
| download | linux-dc1efc3cfaf5e16870a9a7b1b903dcf6e3ef15e8.tar.xz linux-dc1efc3cfaf5e16870a9a7b1b903dcf6e3ef15e8.zip | |
Merge branch 'work.dcache' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs
Pull dcache updates from Al Viro:
"Neil Brown's d_move()/d_path() race fix"
* 'work.dcache' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs:
VFS: close race between getcwd() and d_move()
| -rw-r--r-- | fs/dcache.c | 23 |
1 files changed, 16 insertions, 7 deletions
diff --git a/fs/dcache.c b/fs/dcache.c index c6d996ee2d61..d93872d425d6 100644 --- a/fs/dcache.c +++ b/fs/dcache.c @@ -466,9 +466,11 @@ static void dentry_lru_add(struct dentry *dentry) * d_drop() is used mainly for stuff that wants to invalidate a dentry for some * reason (NFS timeouts or autofs deletes). * - * __d_drop requires dentry->d_lock. + * __d_drop requires dentry->d_lock + * ___d_drop doesn't mark dentry as "unhashed" + * (dentry->d_hash.pprev will be LIST_POISON2, not NULL). */ -void __d_drop(struct dentry *dentry) +static void ___d_drop(struct dentry *dentry) { if (!d_unhashed(dentry)) { struct hlist_bl_head *b; @@ -484,12 +486,17 @@ void __d_drop(struct dentry *dentry) hlist_bl_lock(b); __hlist_bl_del(&dentry->d_hash); - dentry->d_hash.pprev = NULL; hlist_bl_unlock(b); /* After this call, in-progress rcu-walk path lookup will fail. */ write_seqcount_invalidate(&dentry->d_seq); } } + +void __d_drop(struct dentry *dentry) +{ + ___d_drop(dentry); + dentry->d_hash.pprev = NULL; +} EXPORT_SYMBOL(__d_drop); void d_drop(struct dentry *dentry) @@ -2380,7 +2387,7 @@ EXPORT_SYMBOL(d_delete); static void __d_rehash(struct dentry *entry) { struct hlist_bl_head *b = d_hash(entry->d_name.hash); - BUG_ON(!d_unhashed(entry)); + hlist_bl_lock(b); hlist_bl_add_head_rcu(&entry->d_hash, b); hlist_bl_unlock(b); @@ -2815,9 +2822,9 @@ static void __d_move(struct dentry *dentry, struct dentry *target, write_seqcount_begin_nested(&target->d_seq, DENTRY_D_LOCK_NESTED); /* unhash both */ - /* __d_drop does write_seqcount_barrier, but they're OK to nest. */ - __d_drop(dentry); - __d_drop(target); + /* ___d_drop does write_seqcount_barrier, but they're OK to nest. */ + ___d_drop(dentry); + ___d_drop(target); /* Switch the names.. */ if (exchange) @@ -2829,6 +2836,8 @@ static void __d_move(struct dentry *dentry, struct dentry *target, __d_rehash(dentry); if (exchange) __d_rehash(target); + else + target->d_hash.pprev = NULL; /* ... and switch them in the tree */ if (IS_ROOT(dentry)) { |