lkml.org 
[lkml]   [2023]   [Feb]   [26]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
    Patch in this message
    /
    From
    Subject[PATCH AUTOSEL 6.1 56/58] nfsd: clean up potential nfsd_file refcount leaks in COPY codepath
    Date
    From: Jeff Layton <jlayton@kernel.org>

    [ Upstream commit 6ba434cb1a8d403ea9aad1b667c3ea3ad8b3191f ]

    There are two different flavors of the nfsd4_copy struct. One is
    embedded in the compound and is used directly in synchronous copies. The
    other is dynamically allocated, refcounted and tracked in the client
    struture. For the embedded one, the cleanup just involves releasing any
    nfsd_files held on its behalf. For the async one, the cleanup is a bit
    more involved, and we need to dequeue it from lists, unhash it, etc.

    There is at least one potential refcount leak in this code now. If the
    kthread_create call fails, then both the src and dst nfsd_files in the
    original nfsd4_copy object are leaked.

    The cleanup in this codepath is also sort of weird. In the async copy
    case, we'll have up to four nfsd_file references (src and dst for both
    flavors of copy structure). They are both put at the end of
    nfsd4_do_async_copy, even though the ones held on behalf of the embedded
    one outlive that structure.

    Change it so that we always clean up the nfsd_file refs held by the
    embedded copy structure before nfsd4_copy returns. Rework
    cleanup_async_copy to handle both inter and intra copies. Eliminate
    nfsd4_cleanup_intra_ssc since it now becomes a no-op.

    Signed-off-by: Jeff Layton <jlayton@kernel.org>
    Signed-off-by: Chuck Lever <chuck.lever@oracle.com>
    Signed-off-by: Sasha Levin <sashal@kernel.org>
    ---
    fs/nfsd/nfs4proc.c | 23 ++++++++++-------------
    1 file changed, 10 insertions(+), 13 deletions(-)

    diff --git a/fs/nfsd/nfs4proc.c b/fs/nfsd/nfs4proc.c
    index 13603cb017346..9cc498916aa22 100644
    --- a/fs/nfsd/nfs4proc.c
    +++ b/fs/nfsd/nfs4proc.c
    @@ -1530,7 +1530,6 @@ nfsd4_cleanup_inter_ssc(struct vfsmount *ss_mnt, struct file *filp,
    struct nfsd_net *nn = net_generic(dst->nf_net, nfsd_net_id);

    nfs42_ssc_close(filp);
    - nfsd_file_put(dst);
    fput(filp);

    if (!nn) {
    @@ -1597,13 +1596,6 @@ nfsd4_setup_intra_ssc(struct svc_rqst *rqstp,
    &copy->nf_dst);
    }

    -static void
    -nfsd4_cleanup_intra_ssc(struct nfsd_file *src, struct nfsd_file *dst)
    -{
    - nfsd_file_put(src);
    - nfsd_file_put(dst);
    -}
    -
    static void nfsd4_cb_offload_release(struct nfsd4_callback *cb)
    {
    struct nfsd4_cb_offload *cbo =
    @@ -1718,12 +1710,18 @@ static void dup_copy_fields(struct nfsd4_copy *src, struct nfsd4_copy *dst)
    dst->ss_mnt = src->ss_mnt;
    }

    +static void release_copy_files(struct nfsd4_copy *copy)
    +{
    + if (copy->nf_src)
    + nfsd_file_put(copy->nf_src);
    + if (copy->nf_dst)
    + nfsd_file_put(copy->nf_dst);
    +}
    +
    static void cleanup_async_copy(struct nfsd4_copy *copy)
    {
    nfs4_free_copy_state(copy);
    - nfsd_file_put(copy->nf_dst);
    - if (!nfsd4_ssc_is_inter(copy))
    - nfsd_file_put(copy->nf_src);
    + release_copy_files(copy);
    spin_lock(&copy->cp_clp->async_lock);
    list_del(&copy->copies);
    spin_unlock(&copy->cp_clp->async_lock);
    @@ -1783,7 +1781,6 @@ static int nfsd4_do_async_copy(void *data)
    } else {
    nfserr = nfsd4_do_copy(copy, copy->nf_src->nf_file,
    copy->nf_dst->nf_file, false);
    - nfsd4_cleanup_intra_ssc(copy->nf_src, copy->nf_dst);
    }

    do_callback:
    @@ -1847,9 +1844,9 @@ nfsd4_copy(struct svc_rqst *rqstp, struct nfsd4_compound_state *cstate,
    } else {
    status = nfsd4_do_copy(copy, copy->nf_src->nf_file,
    copy->nf_dst->nf_file, true);
    - nfsd4_cleanup_intra_ssc(copy->nf_src, copy->nf_dst);
    }
    out:
    + release_copy_files(copy);
    return status;
    out_err:
    if (async_copy)
    --
    2.39.0
    \
     
     \ /
      Last update: 2023-03-27 00:36    [W:4.116 / U:0.412 seconds]
    ©2003-2020 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site