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NFSv4: Ensure that file unlock requests don't conflict with state recovery 

The unlock path is currently failing to take the nfs_client->cl_sem read
lock, and hence the recovery path may see locks disappear from underneath
it.
Also ensure that it takes the nfs_inode->rwsem read lock so that it there
is no conflict with delegation recalls.

Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>
This commit is contained in:
Trond Myklebust 2008-12-23 15:21:44 -05:00
parent 65de872ed6
commit 19e03c570e
2 changed files with 20 additions and 10 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

26
fs/nfs/nfs4proc.c
View File

@ -3273,6 +3273,8 @@ static struct rpc_task *nfs4_do_unlck(struct file_lock *fl,
static int nfs4_proc_unlck(struct nfs4_state *state, int cmd, struct file_lock *request)
{
struct nfs_client *clp = state->owner->so_client;
struct nfs_inode *nfsi = NFS_I(state->inode);
struct nfs_seqid *seqid;
struct nfs4_lock_state *lsp;
struct rpc_task *task;
@ -3282,8 +3284,15 @@ static int nfs4_proc_unlck(struct nfs4_state *state, int cmd, struct file_lock *
status = nfs4_set_lock_state(state, request);
/* Unlock _before_ we do the RPC call */
request->fl_flags |= FL_EXISTS;
if (do_vfs_lock(request->fl_file, request) == -ENOENT)
down_read(&clp->cl_sem);
down_read(&nfsi->rwsem);
if (do_vfs_lock(request->fl_file, request) == -ENOENT) {
up_read(&nfsi->rwsem);
up_read(&clp->cl_sem);
goto out;
}
up_read(&nfsi->rwsem);
up_read(&clp->cl_sem);
if (status != 0)
goto out;
/* Is this a delegated lock? */
@ -3510,6 +3519,7 @@ static int nfs4_lock_expired(struct nfs4_state *state, struct file_lock *request
static int _nfs4_proc_setlk(struct nfs4_state *state, int cmd, struct file_lock *request)
{
struct nfs_client *clp = state->owner->so_client;
struct nfs_inode *nfsi = NFS_I(state->inode);
unsigned char fl_flags = request->fl_flags;
int status;
@ -3522,18 +3532,13 @@ static int _nfs4_proc_setlk(struct nfs4_state *state, int cmd, struct file_lock
if (status < 0)
goto out;
down_read(&clp->cl_sem);
down_read(&nfsi->rwsem);
if (test_bit(NFS_DELEGATED_STATE, &state->flags)) {
struct nfs_inode *nfsi = NFS_I(state->inode);
/* Yes: cache locks! */
down_read(&nfsi->rwsem);
/* ...but avoid races with delegation recall... */
if (test_bit(NFS_DELEGATED_STATE, &state->flags)) {
request->fl_flags = fl_flags & ~FL_SLEEP;
status = do_vfs_lock(request->fl_file, request);
up_read(&nfsi->rwsem);
goto out_unlock;
}
up_read(&nfsi->rwsem);
request->fl_flags = fl_flags & ~FL_SLEEP;
status = do_vfs_lock(request->fl_file, request);
goto out_unlock;
}
status = _nfs4_do_setlk(state, cmd, request, 0);
if (status != 0)
@ -3543,6 +3548,7 @@ static int _nfs4_proc_setlk(struct nfs4_state *state, int cmd, struct file_lock
if (do_vfs_lock(request->fl_file, request) < 0)
printk(KERN_WARNING "%s: VFS is out of sync with lock manager!\n", __func__);
out_unlock:
up_read(&nfsi->rwsem);
up_read(&clp->cl_sem);
out:
request->fl_flags = fl_flags;

4
fs/nfs/nfs4state.c
View File

@ -849,9 +849,11 @@ static int nfs4_state_mark_reclaim_nograce(struct nfs_client *clp, struct nfs4_s
static int nfs4_reclaim_locks(struct nfs4_state *state, const struct nfs4_state_recovery_ops *ops)
{
struct inode *inode = state->inode;
struct nfs_inode *nfsi = NFS_I(inode);
struct file_lock *fl;
int status = 0;
down_write(&nfsi->rwsem);
for (fl = inode->i_flock; fl != NULL; fl = fl->fl_next) {
if (!(fl->fl_flags & (FL_POSIX|FL_FLOCK)))
continue;
@ -874,8 +876,10 @@ static int nfs4_reclaim_locks(struct nfs4_state *state, const struct nfs4_state_
goto out_err;
}
}
up_write(&nfsi->rwsem);
return 0;
out_err:
up_write(&nfsi->rwsem);
return status;
}