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author | Trond Myklebust <trond.myklebust@hammerspace.com> | 2020-11-25 12:06:14 -0500 |
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committer | Greg Kroah-Hartman <gregkh@linuxfoundation.org> | 2021-01-06 14:45:01 +0100 |
commit | 05a0aec6787885a335a9d3cec7e1cfffee253b84 (patch) | |
tree | 9652556b093435107c90e4fd5762347b30d46c4f /fs/nfs | |
parent | f2dc273475894b50841647c1ee180834c2836c9e (diff) | |
download | linux-stable-05a0aec6787885a335a9d3cec7e1cfffee253b84.tar.gz linux-stable-05a0aec6787885a335a9d3cec7e1cfffee253b84.tar.bz2 linux-stable-05a0aec6787885a335a9d3cec7e1cfffee253b84.zip |
NFSv4: Fix a pNFS layout related use-after-free race when freeing the inode
[ Upstream commit b6d49ecd1081740b6e632366428b960461f8158b ]
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>
Signed-off-by: Sasha Levin <sashal@kernel.org>
Diffstat (limited to 'fs/nfs')
-rw-r--r-- | fs/nfs/nfs4super.c | 2 | ||||
-rw-r--r-- | fs/nfs/pnfs.c | 33 | ||||
-rw-r--r-- | fs/nfs/pnfs.h | 5 |
3 files changed, 37 insertions, 3 deletions
diff --git a/fs/nfs/nfs4super.c b/fs/nfs/nfs4super.c index 6fb7cb6b3f4b..e7a10f5f5405 100644 --- a/fs/nfs/nfs4super.c +++ b/fs/nfs/nfs4super.c @@ -95,7 +95,7 @@ static void nfs4_evict_inode(struct inode *inode) nfs_inode_return_delegation_noreclaim(inode); /* Note that above delegreturn would trigger pnfs return-on-close */ pnfs_return_layout(inode); - pnfs_destroy_layout(NFS_I(inode)); + pnfs_destroy_layout_final(NFS_I(inode)); /* First call standard NFS clear_inode() code */ nfs_clear_inode(inode); } diff --git a/fs/nfs/pnfs.c b/fs/nfs/pnfs.c index 2b9e139a2997..a253384a4710 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); } } @@ -713,8 +718,7 @@ 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); @@ -732,9 +736,34 @@ 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) diff --git a/fs/nfs/pnfs.h b/fs/nfs/pnfs.h index 3ba44819a88a..80fafa29e567 100644 --- a/fs/nfs/pnfs.h +++ b/fs/nfs/pnfs.h @@ -254,6 +254,7 @@ struct pnfs_layout_segment *pnfs_layout_process(struct nfs4_layoutget *lgp); void pnfs_layoutget_free(struct nfs4_layoutget *lgp); void pnfs_free_lseg_list(struct list_head *tmp_list); void pnfs_destroy_layout(struct nfs_inode *); +void pnfs_destroy_layout_final(struct nfs_inode *); void pnfs_destroy_all_layouts(struct nfs_client *); int pnfs_destroy_layouts_byfsid(struct nfs_client *clp, struct nfs_fsid *fsid, @@ -645,6 +646,10 @@ static inline void pnfs_destroy_layout(struct nfs_inode *nfsi) { } +static inline void pnfs_destroy_layout_final(struct nfs_inode *nfsi) +{ +} + static inline struct pnfs_layout_segment * pnfs_get_lseg(struct pnfs_layout_segment *lseg) { |