diff options
| author |   Andy Adamson <andros@citi.umich.edu> | 2006-03-20 13:44:26 -0500 |
|---|---|---|
| committer |   Trond Myklebust <Trond.Myklebust@netapp.com> | 2006-03-20 13:44:26 -0500 |
| commit | 8dc7c3115b611c00006eac3ee5b108296432aab7 (patch) | |
| tree | be44c59907cbdcb6fdf46d0ad9cc140af757acfc /fs/nfsd | |
| parent | locks: remove unused posix_block_lock (diff) | |
| download | linux-dev-8dc7c3115b611c00006eac3ee5b108296432aab7.tar.xz linux-dev-8dc7c3115b611c00006eac3ee5b108296432aab7.zip | |
locks,lockd: fix race in nlmsvc_testlock
posix_test_lock() returns a pointer to a struct file_lock which is unprotected
and can be removed while in use by the caller. Move the conflicting lock from
the return to a parameter, and copy the conflicting lock.
In most cases the caller ends up putting the copy of the conflicting lock on
the stack. On i386, sizeof(struct file_lock) appears to be about 100 bytes.
We're assuming that's reasonable.
Signed-off-by: Andy Adamson <andros@citi.umich.edu>
Signed-off-by: J. Bruce Fields <bfields@citi.umich.edu>
Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>
Diffstat (limited to 'fs/nfsd')
| -rw-r--r-- | fs/nfsd/nfs4state.c | 13 |
1 files changed, 6 insertions, 7 deletions
diff --git a/fs/nfsd/nfs4state.c b/fs/nfsd/nfs4state.c index 1143cfb64549..f6ab762bea99 100644 --- a/fs/nfsd/nfs4state.c +++ b/fs/nfsd/nfs4state.c @@ -2639,7 +2639,7 @@ nfsd4_lock(struct svc_rqst *rqstp, struct svc_fh *current_fh, struct nfsd4_lock struct nfs4_stateid *lock_stp; struct file *filp; struct file_lock file_lock; - struct file_lock *conflock; + struct file_lock conflock; int status = 0; unsigned int strhashval; @@ -2775,11 +2775,11 @@ conflicting_lock: /* XXX There is a race here. Future patch needed to provide * an atomic posix_lock_and_test_file */ - if (!(conflock = posix_test_lock(filp, &file_lock))) { + if (!posix_test_lock(filp, &file_lock, &conflock)) { status = nfserr_serverfault; goto out; } - nfs4_set_lock_denied(conflock, &lock->lk_denied); + nfs4_set_lock_denied(&conflock, &lock->lk_denied); out: if (status && lock->lk_is_new && lock_sop) release_stateowner(lock_sop); @@ -2800,7 +2800,7 @@ nfsd4_lockt(struct svc_rqst *rqstp, struct svc_fh *current_fh, struct nfsd4_lock struct inode *inode; struct file file; struct file_lock file_lock; - struct file_lock *conflicting_lock; + struct file_lock conflock; int status; if (nfs4_in_grace()) @@ -2864,10 +2864,9 @@ nfsd4_lockt(struct svc_rqst *rqstp, struct svc_fh *current_fh, struct nfsd4_lock file.f_dentry = current_fh->fh_dentry; status = nfs_ok; - conflicting_lock = posix_test_lock(&file, &file_lock); - if (conflicting_lock) { + if (posix_test_lock(&file, &file_lock, &conflock)) { status = nfserr_denied; - nfs4_set_lock_denied(conflicting_lock, &lockt->lt_denied); + nfs4_set_lock_denied(&conflock, &lockt->lt_denied); } out: nfs4_unlock_state(); |