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nfsd: fix potential lease memory leak in nfs4_setlease 

It's unlikely to ever occur, but if there were already a lease set on
the file then we could end up getting back a different pointer on a
successful setlease attempt than the one we allocated. If that happens,
the one we allocated could leak.

In practice, I don't think this will happen due to the fact that we only
try to set up the lease once per nfs4_file, but this error handling is a
bit more correct given the current lease API.

Cc: J. Bruce Fields <bfields@fieldses.org>
Signed-off-by: Jeff Layton <jlayton@primarydata.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
This commit is contained in:
Jeff Layton 2014-08-22 12:26:36 -04:00
parent bfe8602436
commit 415b96c5a1
1 changed files with 5 additions and 2 deletions

7
fs/nfsd/nfs4state.c
View File

@ -3781,7 +3781,7 @@ static struct file_lock *nfs4_alloc_init_lease(struct nfs4_file *fp, int flag)
static int nfs4_setlease(struct nfs4_delegation *dp) static int nfs4_setlease(struct nfs4_delegation *dp)
{ {
struct nfs4_file *fp = dp->dl_stid.sc_file; struct nfs4_file *fp = dp->dl_stid.sc_file;
struct file_lock *fl; struct file_lock *fl, *ret;
struct file *filp; struct file *filp;
int status = 0; int status = 0;
@ -3795,11 +3795,14 @@ static int nfs4_setlease(struct nfs4_delegation *dp)
return -EBADF; return -EBADF;
} }
fl->fl_file = filp; fl->fl_file = filp;
status = vfs_setlease(filp, fl->fl_type, &fl); ret = fl;
status = vfs_setlease(filp, fl->fl_type, &ret);
if (status) { if (status) {
locks_free_lock(fl); locks_free_lock(fl);
goto out_fput; goto out_fput;
} }
if (ret != fl)
locks_free_lock(fl);
spin_lock(&state_lock); spin_lock(&state_lock);
spin_lock(&fp->fi_lock); spin_lock(&fp->fi_lock);
/* Did the lease get broken before we took the lock? */ /* Did the lease get broken before we took the lock? */