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| author | Trond Myklebust <trond.myklebust@hammerspace.com> | 2020-11-25 18:06:14 +0100 |
|---|---|---|
| committer | Trond Myklebust <trond.myklebust@hammerspace.com> | 2020-12-02 20:05:54 +0100 |
| commit | b6d49ecd1081740b6e632366428b960461f8158b (patch) | |
| tree | 35779fadb7de97f778e36a343d14d92e0d17f19e /fs/nfs/pnfs.c | |
| parent | NFSv4: Fix open coded xdr_stream_remaining() (diff) | |
| download | linux-b6d49ecd1081740b6e632366428b960461f8158b.tar.xz linux-b6d49ecd1081740b6e632366428b960461f8158b.zip | |
NFSv4: Fix a pNFS layout related use-after-free race when freeing the inode
When returning the layout in nfs4_evict_inode(), we need to ensure that
the layout is actually done being freed before we can proceed to free the
inode itself.
Signed-off-by: Trond Myklebust <trond.myklebust@hammerspace.com>
Diffstat (limited to 'fs/nfs/pnfs.c')
| -rw-r--r-- | fs/nfs/pnfs.c | 33 |
1 files changed, 31 insertions, 2 deletions
diff --git a/fs/nfs/pnfs.c b/fs/nfs/pnfs.c index 0e50b9d45c32..07f59dc8cb2e 100644 --- a/fs/nfs/pnfs.c +++ b/fs/nfs/pnfs.c @@ -294,6 +294,7 @@ void pnfs_put_layout_hdr(struct pnfs_layout_hdr *lo) { struct inode *inode; + unsigned long i_state; if (!lo) return; @@ -304,8 +305,12 @@ pnfs_put_layout_hdr(struct pnfs_layout_hdr *lo) if (!list_empty(&lo->plh_segs)) WARN_ONCE(1, "NFS: BUG unfreed layout segments.\n"); pnfs_detach_layout_hdr(lo); + i_state = inode->i_state; spin_unlock(&inode->i_lock); pnfs_free_layout_hdr(lo); + /* Notify pnfs_destroy_layout_final() that we're done */ + if (i_state & (I_FREEING | I_CLEAR)) + wake_up_var(lo); } } @@ -734,8 +739,7 @@ pnfs_free_lseg_list(struct list_head *free_me) } } -void -pnfs_destroy_layout(struct nfs_inode *nfsi) +static struct pnfs_layout_hdr *__pnfs_destroy_layout(struct nfs_inode *nfsi) { struct pnfs_layout_hdr *lo; LIST_HEAD(tmp_list); @@ -753,9 +757,34 @@ pnfs_destroy_layout(struct nfs_inode *nfsi) pnfs_put_layout_hdr(lo); } else spin_unlock(&nfsi->vfs_inode.i_lock); + return lo; +} + +void pnfs_destroy_layout(struct nfs_inode *nfsi) +{ + __pnfs_destroy_layout(nfsi); } EXPORT_SYMBOL_GPL(pnfs_destroy_layout); +static bool pnfs_layout_removed(struct nfs_inode *nfsi, + struct pnfs_layout_hdr *lo) +{ + bool ret; + + spin_lock(&nfsi->vfs_inode.i_lock); + ret = nfsi->layout != lo; + spin_unlock(&nfsi->vfs_inode.i_lock); + return ret; +} + +void pnfs_destroy_layout_final(struct nfs_inode *nfsi) +{ + struct pnfs_layout_hdr *lo = __pnfs_destroy_layout(nfsi); + + if (lo) + wait_var_event(lo, pnfs_layout_removed(nfsi, lo)); +} + static bool pnfs_layout_add_bulk_destroy_list(struct inode *inode, struct list_head *layout_list) |