unfs makes use of utime() which is unsuitable to set last access and modification times for symlinks. So make use of the O_PATH flag to open() and use the futimens() function.
As a side effect this is less racy and improves resolution from seconds to nanoseconds. Note this will break builds of unfs on Windows. The futimens() function is specified in POSIX.1-2008, so this shouldn't be a problem for other platforms. Signed-off-by: Uwe Kleine-König <[email protected]> --- Hello, note I didn't try to contact upstream. Best regards Uwe ...5-attr-use-futimens-instead-of-utime.patch | 102 ++++++++++++++++++ ...-O_PATH-to-set-attributes-of-symlink.patch | 81 ++++++++++++++ patches/unfs3-0.9.22/series | 4 +- 3 files changed, 186 insertions(+), 1 deletion(-) create mode 100644 patches/unfs3-0.9.22/0005-attr-use-futimens-instead-of-utime.patch create mode 100644 patches/unfs3-0.9.22/0006-attr-make-use-of-O_PATH-to-set-attributes-of-symlink.patch diff --git a/patches/unfs3-0.9.22/0005-attr-use-futimens-instead-of-utime.patch b/patches/unfs3-0.9.22/0005-attr-use-futimens-instead-of-utime.patch new file mode 100644 index 000000000000..401142fb1b16 --- /dev/null +++ b/patches/unfs3-0.9.22/0005-attr-use-futimens-instead-of-utime.patch @@ -0,0 +1,102 @@ +From: =?UTF-8?q?Uwe=20Kleine-K=C3=B6nig?= <[email protected]> +Date: Tue, 18 Feb 2020 15:20:12 +0100 +Subject: [PATCH] attr: use futimens() instead of utime() + +The former has two relevant advantages: It works on file descriptors +instead of a path name and it has nano second resolution (instead of only +seconds). + +Note, I don't know about Windows which is probably broken by this commit +as I assume it doesn't support futimens(). +--- + attr.c | 53 ++++++++++++++++++++++++++++++++++++++++++++++++----- + 1 file changed, 48 insertions(+), 5 deletions(-) + +diff --git a/attr.c b/attr.c +index 2653ed0a16bb..08c9d24cb446 100644 +--- a/attr.c ++++ b/attr.c +@@ -265,12 +265,51 @@ post_op_attr get_post_cached(struct svc_req * req) + return get_post_buf(st_cache, req); + } + ++static nfsstat3 set_time(int fd, sattr3 new) ++{ ++ if (new.atime.set_it != DONT_CHANGE || new.mtime.set_it != DONT_CHANGE) { ++ ++ /* atime in t[0], mtime in t[1] */ ++ struct timespec t[2]; ++ int res; ++ ++ /* compute atime to set */ ++ if (new.atime.set_it == SET_TO_SERVER_TIME) { ++ t[0].tv_sec = UTIME_NOW; ++ t[0].tv_nsec = UTIME_NOW; ++ } else if (new.atime.set_it == SET_TO_CLIENT_TIME) { ++ t[0].tv_sec = new.atime.set_atime_u.atime.seconds; ++ t[0].tv_nsec = new.atime.set_atime_u.atime.nseconds; ++ } else { /* DONT_CHANGE */ ++ t[0].tv_sec = UTIME_OMIT; ++ t[0].tv_nsec = UTIME_OMIT; ++ } ++ ++ /* compute mtime to set */ ++ if (new.mtime.set_it == SET_TO_SERVER_TIME) { ++ t[1].tv_sec = UTIME_NOW; ++ t[1].tv_nsec = UTIME_NOW; ++ } else if (new.mtime.set_it == SET_TO_CLIENT_TIME) { ++ t[1].tv_sec = new.mtime.set_mtime_u.mtime.seconds; ++ t[1].tv_nsec = new.mtime.set_mtime_u.mtime.nseconds; ++ } else { /* DONT_CHANGE */ ++ t[1].tv_sec = UTIME_OMIT; ++ t[1].tv_nsec = UTIME_OMIT; ++ } ++ ++ res = futimens(fd, &t); ++ if (res == -1) ++ return setattr_err(); ++ } ++ return NFS3_OK; ++} ++ + /* + * setting of time, races with local filesystem + * + * there is no futimes() function in POSIX or Linux + */ +-static nfsstat3 set_time(const char *path, backend_statstruct buf, sattr3 new) ++static nfsstat3 set_time_path(const char *path, backend_statstruct buf, sattr3 new) + { + time_t new_atime, new_mtime; + struct utimbuf utim; +@@ -358,7 +397,7 @@ static nfsstat3 set_attr_unsafe(const char *path, nfs_fh3 nfh, sattr3 new) + return setattr_err(); + } + +- return set_time(path, buf, new); ++ return set_time_path(path, buf, new); + } + + /* +@@ -454,14 +493,18 @@ nfsstat3 set_attr(const char *path, nfs_fh3 nfh, sattr3 new) + } + } + ++ /* finally, set times */ ++ res = set_time(fd, new); ++ if (res != NFS3_OK) { ++ backend_close(fd); ++ return res; ++ } ++ + res = backend_close(fd); + if (res == -1) { + /* error on close probably means attributes didn't make it */ + return NFS3ERR_IO; + } +- +- /* finally, set times */ +- return set_time(path, buf, new); + } + + /* diff --git a/patches/unfs3-0.9.22/0006-attr-make-use-of-O_PATH-to-set-attributes-of-symlink.patch b/patches/unfs3-0.9.22/0006-attr-make-use-of-O_PATH-to-set-attributes-of-symlink.patch new file mode 100644 index 000000000000..798927a520e6 --- /dev/null +++ b/patches/unfs3-0.9.22/0006-attr-make-use-of-O_PATH-to-set-attributes-of-symlink.patch @@ -0,0 +1,81 @@ +From: =?UTF-8?q?Uwe=20Kleine-K=C3=B6nig?= <[email protected]> +Date: Tue, 18 Feb 2020 15:23:52 +0100 +Subject: [PATCH] attr: make use of O_PATH to set attributes of symlinks and + devices + +This fixes setting atime/mtime for symlinks which before this patch changed +the timestamps for the symlink's target (and resulted in an error if the +symlink is dangling). +--- + attr.c | 24 ++++++++++++++++++++++-- + 1 file changed, 22 insertions(+), 2 deletions(-) + +diff --git a/attr.c b/attr.c +index 08c9d24cb446..ae2a759e9c86 100644 +--- a/attr.c ++++ b/attr.c +@@ -304,6 +304,7 @@ static nfsstat3 set_time(int fd, sattr3 new) + return NFS3_OK; + } + ++#ifndef O_PATH + /* + * setting of time, races with local filesystem + * +@@ -399,6 +400,7 @@ static nfsstat3 set_attr_unsafe(const char *path, nfs_fh3 nfh, sattr3 new) + + return set_time_path(path, buf, new); + } ++#endif /* #ifndef O_PATH */ + + /* + * set attributes of an object +@@ -410,13 +412,29 @@ nfsstat3 set_attr(const char *path, nfs_fh3 nfh, sattr3 new) + uid_t new_uid; + gid_t new_gid; + backend_statstruct buf; ++#ifdef O_PATH ++ int flags = O_PATH | O_NOFOLLOW; ++#endif + + res = backend_lstat(path, &buf); + if (res != 0) + return NFS3ERR_STALE; + ++#ifdef O_PATH ++ ++ if (new.size.set_it == TRUE) { ++ if (!S_ISREG(buf.st_mode)) ++ return NFS3ERR_NOTSUPP; ++ flags = O_WRONLY | O_NONBLOCK; ++ } ++ ++ fd = backend_open(path, flags); ++ if (fd < 0) ++ return NFS3ERR_STALE; ++ ++#else + /* +- * don't open(2) device nodes, it could trigger ++ * don't open(2) device nodes without O_PATH, it could trigger + * module loading on the server + */ + if (S_ISBLK(buf.st_mode) || S_ISCHR(buf.st_mode)) +@@ -424,7 +442,7 @@ nfsstat3 set_attr(const char *path, nfs_fh3 nfh, sattr3 new) + + #ifdef S_ISLNK + /* +- * opening a symlink would open the underlying file, ++ * opening a symlink without O_PATH would open the underlying file, + * don't try to do that + */ + if (S_ISLNK(buf.st_mode)) +@@ -441,6 +459,8 @@ nfsstat3 set_attr(const char *path, nfs_fh3 nfh, sattr3 new) + if (fd == -1) + return set_attr_unsafe(path, nfh, new); + ++#endif /* #ifdef O_PATH / else */ ++ + res = backend_fstat(fd, &buf); + if (res == -1) { + backend_close(fd); diff --git a/patches/unfs3-0.9.22/series b/patches/unfs3-0.9.22/series index 3c8683ef546a..deda41f14aef 100644 --- a/patches/unfs3-0.9.22/series +++ b/patches/unfs3-0.9.22/series @@ -4,4 +4,6 @@ 0002-fix-unfs3-build-with-recent-versions-of-flex.patch 0003-64-bit-fixes-don-t-assume-that-long-is-the-same-size.patch 0004-use-libtirpc-if-found.patch -# b3936a9a6ca0c9fd1c164603ca1d2064 - git-ptx-patches magic +0005-attr-use-futimens-instead-of-utime.patch +0006-attr-make-use-of-O_PATH-to-set-attributes-of-symlink.patch +# 0534e0228eabedcabb5e164a284ad3f5 - git-ptx-patches magic -- 2.25.0 _______________________________________________ ptxdist mailing list [email protected]
