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author | Al Viro <viro@zeniv.linux.org.uk> | 2016-05-02 19:45:47 -0400 |
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committer | Al Viro <viro@zeniv.linux.org.uk> | 2016-05-02 19:45:47 -0400 |
commit | 84695ffee7987ee1e581be4c4696e47e1a29403b (patch) | |
tree | 78ca09a96ecd6a6b5f4fae744c381968635af68d /fs/nfs/nfs3acl.c | |
parent | bf16200689118d19de1b8d2a3c314fc21f5dc7bb (diff) | |
parent | ce23e640133484eebc20ca7b7668388213e11327 (diff) | |
download | linux-stable-84695ffee7987ee1e581be4c4696e47e1a29403b.tar.gz linux-stable-84695ffee7987ee1e581be4c4696e47e1a29403b.tar.bz2 linux-stable-84695ffee7987ee1e581be4c4696e47e1a29403b.zip |
Merge getxattr prototype change into work.lookups
The rest of work.xattr stuff isn't needed for this branch
Diffstat (limited to 'fs/nfs/nfs3acl.c')
-rw-r--r-- | fs/nfs/nfs3acl.c | 43 |
1 files changed, 41 insertions, 2 deletions
diff --git a/fs/nfs/nfs3acl.c b/fs/nfs/nfs3acl.c index 17c0fa1eccfa..720d92f5abfb 100644 --- a/fs/nfs/nfs3acl.c +++ b/fs/nfs/nfs3acl.c @@ -11,6 +11,38 @@ #define NFSDBG_FACILITY NFSDBG_PROC +/* + * nfs3_prepare_get_acl, nfs3_complete_get_acl, nfs3_abort_get_acl: Helpers for + * caching get_acl results in a race-free way. See fs/posix_acl.c:get_acl() + * for explanations. + */ +static void nfs3_prepare_get_acl(struct posix_acl **p) +{ + struct posix_acl *sentinel = uncached_acl_sentinel(current); + + if (cmpxchg(p, ACL_NOT_CACHED, sentinel) != ACL_NOT_CACHED) { + /* Not the first reader or sentinel already in place. */ + } +} + +static void nfs3_complete_get_acl(struct posix_acl **p, struct posix_acl *acl) +{ + struct posix_acl *sentinel = uncached_acl_sentinel(current); + + /* Only cache the ACL if our sentinel is still in place. */ + posix_acl_dup(acl); + if (cmpxchg(p, sentinel, acl) != sentinel) + posix_acl_release(acl); +} + +static void nfs3_abort_get_acl(struct posix_acl **p) +{ + struct posix_acl *sentinel = uncached_acl_sentinel(current); + + /* Remove our sentinel upon failure. */ + cmpxchg(p, sentinel, ACL_NOT_CACHED); +} + struct posix_acl *nfs3_get_acl(struct inode *inode, int type) { struct nfs_server *server = NFS_SERVER(inode); @@ -55,6 +87,11 @@ struct posix_acl *nfs3_get_acl(struct inode *inode, int type) if (res.fattr == NULL) return ERR_PTR(-ENOMEM); + if (args.mask & NFS_ACL) + nfs3_prepare_get_acl(&inode->i_acl); + if (args.mask & NFS_DFACL) + nfs3_prepare_get_acl(&inode->i_default_acl); + status = rpc_call_sync(server->client_acl, &msg, 0); dprintk("NFS reply getacl: %d\n", status); @@ -89,12 +126,12 @@ struct posix_acl *nfs3_get_acl(struct inode *inode, int type) } if (res.mask & NFS_ACL) - set_cached_acl(inode, ACL_TYPE_ACCESS, res.acl_access); + nfs3_complete_get_acl(&inode->i_acl, res.acl_access); else forget_cached_acl(inode, ACL_TYPE_ACCESS); if (res.mask & NFS_DFACL) - set_cached_acl(inode, ACL_TYPE_DEFAULT, res.acl_default); + nfs3_complete_get_acl(&inode->i_default_acl, res.acl_default); else forget_cached_acl(inode, ACL_TYPE_DEFAULT); @@ -108,6 +145,8 @@ struct posix_acl *nfs3_get_acl(struct inode *inode, int type) } getout: + nfs3_abort_get_acl(&inode->i_acl); + nfs3_abort_get_acl(&inode->i_default_acl); posix_acl_release(res.acl_access); posix_acl_release(res.acl_default); nfs_free_fattr(res.fattr); |