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| author | Karel Zak | 2017-11-16 12:16:09 +0100 |
|---|---|---|
| committer | Karel Zak | 2017-11-16 12:16:09 +0100 |
| commit | 42ee788268880e5dd3402f2179242cdb361ffe20 (patch) | |
| tree | 6acdd00eb098d6a97574bee427bdb83540b1a329 /libmount/src | |
| parent | libblkid: Add support for Micron mpool formatted drives (diff) | |
| download | kernel-qcow2-util-linux-42ee788268880e5dd3402f2179242cdb361ffe20.tar.gz kernel-qcow2-util-linux-42ee788268880e5dd3402f2179242cdb361ffe20.tar.xz kernel-qcow2-util-linux-42ee788268880e5dd3402f2179242cdb361ffe20.zip | |
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 <dmjacobsen@lbl.gov>
Signed-off-by: Karel Zak <kzak@redhat.com>
Diffstat (limited to 'libmount/src')
| -rw-r--r-- | libmount/src/context_mount.c | 28 | ||||
| -rw-r--r-- | libmount/src/utils.c | 2 |
2 files changed, 21 insertions, 9 deletions
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 diff --git a/libmount/src/utils.c b/libmount/src/utils.c index 5db5494d3..56cdc206d 100644 --- a/libmount/src/utils.c +++ b/libmount/src/utils.c @@ -216,6 +216,8 @@ int mnt_is_readonly(const char *path) { struct timespec times[2]; + DBG(UTILS, ul_debug(" doing utimensat() based write test")); + times[0].tv_nsec = UTIME_NOW; /* atime */ times[1].tv_nsec = UTIME_OMIT; /* mtime */ |