From 42ee788268880e5dd3402f2179242cdb361ffe20 Mon Sep 17 00:00:00 2001 From: Karel Zak Date: Thu, 16 Nov 2017 12:16:09 +0100 Subject: libmount: minimize utimensat() write test usage utimensat() is pretty expensive when mounting parallel filesystems from the same source. It's possible to ignore all this if mtab is not writable. Note that this change is irrelevant for default util-linux builds where all around mtab is already disabled since v2.30 (commit 89958178f6d6ebe0944d423feaea66be521fff43). This change is relevant only for users who still use --enable-libmount-support-mtab. Reported-by: Douglas Jacobsen Signed-off-by: Karel Zak --- libmount/src/context_mount.c | 28 +++++++++++++++++++--------- 1 file changed, 19 insertions(+), 9 deletions(-) (limited to 'libmount/src/context_mount.c') diff --git a/libmount/src/context_mount.c b/libmount/src/context_mount.c index 79322c061..139fb5a28 100644 --- a/libmount/src/context_mount.c +++ b/libmount/src/context_mount.c @@ -998,7 +998,13 @@ int mnt_context_do_mount(struct libmnt_context *cxt) #ifdef USE_LIBMOUNT_SUPPORT_MTAB if (mnt_context_get_status(cxt) && !mnt_context_is_fake(cxt) - && !cxt->helper) { + && !cxt->helper + && mnt_context_mtab_writable(cxt)) { + + int is_rdonly = -1; + + DBG(CXT, ul_debugobj(cxt, "checking for RDONLY mismatch")); + /* * Mounted by mount(2), do some post-mount checks * @@ -1007,11 +1013,13 @@ int mnt_context_do_mount(struct libmnt_context *cxt) * avoid 'ro' in mtab and 'rw' in /proc/mounts. */ if ((cxt->mountflags & MS_BIND) - && (cxt->mountflags & MS_RDONLY) - && !mnt_is_readonly(mnt_context_get_target(cxt))) + && (cxt->mountflags & MS_RDONLY)) { - mnt_context_set_mflags(cxt, - cxt->mountflags & ~MS_RDONLY); + if (is_rdonly < 0) + is_rdonly = mnt_is_readonly(mnt_context_get_target(cxt)); + if (!is_rdonly) + mnt_context_set_mflags(cxt, cxt->mountflags & ~MS_RDONLY); + } /* Kernel can silently add MS_RDONLY flag when mounting file @@ -1019,11 +1027,13 @@ int mnt_context_do_mount(struct libmnt_context *cxt) * 'ro' in /proc/mounts and 'rw' in mtab. */ if (!(cxt->mountflags & (MS_RDONLY | MS_MOVE)) - && !mnt_context_propagation_only(cxt) - && mnt_is_readonly(mnt_context_get_target(cxt))) + && !mnt_context_propagation_only(cxt)) { - mnt_context_set_mflags(cxt, - cxt->mountflags | MS_RDONLY); + if (is_rdonly < 0) + is_rdonly = mnt_is_readonly(mnt_context_get_target(cxt)); + if (is_rdonly) + mnt_context_set_mflags(cxt, cxt->mountflags | MS_RDONLY); + } } #endif -- cgit v1.2.3-55-g7522