From 6bcc034eac79873468cdfd1ccea9f25ee67c4500 Mon Sep 17 00:00:00 2001 From: Jeff Layton Date: Sat, 9 Aug 2014 10:22:40 -0400 Subject: [PATCH] nfsd: protect lease-related nfs4_file fields with fi_lock Currently these fields are protected with the state_lock, but that doesn't really make a lot of sense. These fields are "private" to the nfs4_file, and can be protected with the more granular fi_lock. The fi_lock is already held when setting these fields. Make the code hold the fp->fi_lock when clearing the lease-related fields in the nfs4_file, and no longer require that the state_lock be held when calling into this function. To prevent lock inversion with the i_lock, we also move the vfs_setlease and fput calls outside of the fi_lock. This also sets us up for allowing vfs_setlease calls to block in the future. Finally, remove a redundant NULL pointer check. unhash_delegation_locked locks the fp->fi_lock prior to that check, so fp in that function must never be NULL. Signed-off-by: Jeff Layton Signed-off-by: J. Bruce Fields --- fs/nfsd/nfs4state.c | 22 +++++++++++++--------- 1 file changed, 13 insertions(+), 9 deletions(-) diff --git a/fs/nfsd/nfs4state.c b/fs/nfsd/nfs4state.c index 2e80a59e7e91..309ec3b1090a 100644 --- a/fs/nfsd/nfs4state.c +++ b/fs/nfsd/nfs4state.c @@ -673,15 +673,20 @@ nfs4_put_stid(struct nfs4_stid *s) static void nfs4_put_deleg_lease(struct nfs4_file *fp) { - lockdep_assert_held(&state_lock); + struct file *filp = NULL; + struct file_lock *fl; - if (!fp->fi_lease) - return; - if (atomic_dec_and_test(&fp->fi_delegees)) { - vfs_setlease(fp->fi_deleg_file, F_UNLCK, &fp->fi_lease); + spin_lock(&fp->fi_lock); + if (fp->fi_lease && atomic_dec_and_test(&fp->fi_delegees)) { + swap(filp, fp->fi_deleg_file); + fl = fp->fi_lease; fp->fi_lease = NULL; - fput(fp->fi_deleg_file); - fp->fi_deleg_file = NULL; + } + spin_unlock(&fp->fi_lock); + + if (filp) { + vfs_setlease(filp, F_UNLCK, &fl); + fput(filp); } } @@ -717,8 +722,7 @@ unhash_delegation_locked(struct nfs4_delegation *dp) list_del_init(&dp->dl_recall_lru); list_del_init(&dp->dl_perfile); spin_unlock(&fp->fi_lock); - if (fp) - nfs4_put_deleg_lease(fp); + nfs4_put_deleg_lease(fp); } static void destroy_delegation(struct nfs4_delegation *dp) -- GitLab