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NFS: Ensure we always hold the BKL when dereferencing inode->i_flock

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Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>
This commit is contained in:
Trond Myklebust 2009-06-17 13:23:00 -07:00
parent 965b5d6791
commit 3f09df70e3
2 changed files with 23 additions and 2 deletions
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16
fs/nfs/delegation.c
View file

@ -70,15 +70,24 @@ static int nfs_delegation_claim_locks(struct nfs_open_context *ctx, struct nfs4_
struct file_lock *fl;
int status = 0;
if (inode->i_flock == NULL)
goto out;
/* Protect inode->i_flock using the BKL */
lock_kernel();
for (fl = inode->i_flock; fl != NULL; fl = fl->fl_next) {
if (!(fl->fl_flags & (FL_POSIX|FL_FLOCK)))
continue;
if (nfs_file_open_context(fl->fl_file) != ctx)
continue;
unlock_kernel();
status = nfs4_lock_delegation_recall(state, fl);
if (status < 0)
break;
goto out;
lock_kernel();
}
unlock_kernel();
out:
return status;
}
@ -256,7 +265,10 @@ static int __nfs_inode_return_delegation(struct inode *inode, struct nfs_delegat
struct nfs_inode *nfsi = NFS_I(inode);
nfs_msync_inode(inode);
/* Guard against new delegated open calls */
/*
* Guard against new delegated open/lock/unlock calls and against
* state recovery
*/
down_write(&nfsi->rwsem);
nfs_delegation_claim_opens(inode, &delegation->stateid);
up_write(&nfsi->rwsem);

9
fs/nfs/nfs4state.c
View file

@ -847,12 +847,19 @@ static int nfs4_reclaim_locks(struct nfs4_state *state, const struct nfs4_state_
struct file_lock *fl;
int status = 0;
if (inode->i_flock == NULL)
return 0;
/* Guard against delegation returns and new lock/unlock calls */
down_write(&nfsi->rwsem);
/* Protect inode->i_flock using the BKL */
lock_kernel();
for (fl = inode->i_flock; fl != NULL; fl = fl->fl_next) {
if (!(fl->fl_flags & (FL_POSIX|FL_FLOCK)))
continue;
if (nfs_file_open_context(fl->fl_file)->state != state)
continue;
unlock_kernel();
status = ops->recover_lock(state, fl);
switch (status) {
case 0:
@ -875,7 +882,9 @@ static int nfs4_reclaim_locks(struct nfs4_state *state, const struct nfs4_state_
/* kill_proc(fl->fl_pid, SIGLOST, 1); */
status = 0;
}
lock_kernel();
}
unlock_kernel();
out:
up_write(&nfsi->rwsem);
return status;