From c72e9f343f3967fcb936e1131430a6853f1e1d33 Mon Sep 17 00:00:00 2001 From: Dave Chiluk Date: Mon, 31 Aug 2015 16:07:58 -0500 Subject: [PATCH 1/2] mountlist: add me_mntroot field on Linux machines * lib/mountlist.c (read_file_system_list): Populate me_mntroot in mount_entry so Linux machines based on /proc/self/mountinfo can distinguish between bind mounts and original mounts. In reality bind mounts aren't treated differently than mountroot=/ mounts by the kernel, but the user often wants these bind mounts distinguished. * lib/mountlist.h (struct mount_entry): Add me_mntroot element. More details at https://pad.lv/1432871 Upstream-commit: c6148bca89e9465fd6ba3a10d273ec4cb58c2dbe Signed-off-by: Kamil Dudka --- lib/mountlist.c | 25 ++++++++++++++++++++++--- lib/mountlist.h | 2 ++ 2 files changed, 24 insertions(+), 3 deletions(-) diff --git a/lib/mountlist.c b/lib/mountlist.c index 6f04f55..08ade6f 100644 --- a/lib/mountlist.c +++ b/lib/mountlist.c @@ -447,6 +447,7 @@ read_file_system_list (bool need_fs_type) me = xmalloc (sizeof *me); me->me_devname = xstrdup (mnt->mnt_fsname); me->me_mountdir = xstrdup (mnt->mnt_dir); + me->me_mntroot = NULL; me->me_type = xstrdup (mnt->mnt_type); me->me_type_malloced = 1; me->me_dummy = ME_DUMMY (me->me_devname, me->me_type); @@ -478,7 +479,8 @@ read_file_system_list (bool need_fs_type) while (getline (&line, &buf_size, fp) != -1) { unsigned int devmaj, devmin; - int target_s, target_e, type_s, type_e, source_s, source_e; + int target_s, target_e, type_s, type_e; + int source_s, source_e, mntroot_s, mntroot_e; char test; char *dash; int rc; @@ -486,13 +488,15 @@ read_file_system_list (bool need_fs_type) rc = sscanf(line, "%*u " /* id - discarded */ "%*u " /* parent - discarded */ "%u:%u " /* dev major:minor */ - "%*s " /* mountroot - discarded */ + "%n%*s%n " /* mountroot */ "%n%*s%n" /* target, start and end */ "%c", /* more data... */ &devmaj, &devmin, + &mntroot_s, &mntroot_e, &target_s, &target_e, &test); - if (rc != 3 && rc != 5) /* 5 if %n included in count. */ + + if (rc != 3 && rc != 7) /* 7 if %n included in count. */ continue; /* skip optional fields, terminated by " - " */ @@ -511,16 +515,19 @@ read_file_system_list (bool need_fs_type) continue; /* manipulate the sub-strings in place. */ + line[mntroot_e] = '\0'; line[target_e] = '\0'; dash[type_e] = '\0'; dash[source_e] = '\0'; unescape_tab (dash + source_s); unescape_tab (line + target_s); + unescape_tab (line + mntroot_s); me = xmalloc (sizeof *me); me->me_devname = xstrdup (dash + source_s); me->me_mountdir = xstrdup (line + target_s); + me->me_mntroot = xstrdup (line + mntroot_s); me->me_type = xstrdup (dash + type_s); me->me_type_malloced = 1; me->me_dev = makedev (devmaj, devmin); @@ -566,6 +573,7 @@ read_file_system_list (bool need_fs_type) me = xmalloc (sizeof *me); me->me_devname = xstrdup (mnt->mnt_fsname); me->me_mountdir = xstrdup (mnt->mnt_dir); + me->me_mntroot = NULL; me->me_type = xstrdup (mnt->mnt_type); me->me_type_malloced = 1; me->me_dummy = ME_DUMMY (me->me_devname, me->me_type, bind); @@ -598,6 +606,7 @@ read_file_system_list (bool need_fs_type) me = xmalloc (sizeof *me); me->me_devname = xstrdup (fsp->f_mntfromname); me->me_mountdir = xstrdup (fsp->f_mntonname); + me->me_mntroot = NULL; me->me_type = fs_type; me->me_type_malloced = 0; me->me_dummy = ME_DUMMY (me->me_devname, me->me_type); @@ -624,6 +633,7 @@ read_file_system_list (bool need_fs_type) me = xmalloc (sizeof *me); me->me_devname = xstrdup (fsp->f_mntfromname); me->me_mountdir = xstrdup (fsp->f_mntonname); + me->me_mntroot = NULL; me->me_type = xstrdup (fsp->f_fstypename); me->me_type_malloced = 1; me->me_dummy = ME_DUMMY (me->me_devname, me->me_type); @@ -650,6 +660,7 @@ read_file_system_list (bool need_fs_type) me = xmalloc (sizeof *me); me->me_devname = xstrdup (fsd.fd_req.devname); me->me_mountdir = xstrdup (fsd.fd_req.path); + me->me_mntroot = NULL; me->me_type = gt_names[fsd.fd_req.fstype]; me->me_type_malloced = 0; me->me_dummy = ME_DUMMY (me->me_devname, me->me_type); @@ -748,6 +759,7 @@ read_file_system_list (bool need_fs_type) me->me_devname = xstrdup (fi.device_name[0] != '\0' ? fi.device_name : fi.fsh_name); me->me_mountdir = xstrdup (re != NULL ? re->name : fi.fsh_name); + me->me_mntroot = NULL; me->me_type = xstrdup (fi.fsh_name); me->me_type_malloced = 1; me->me_dev = fi.dev; @@ -797,6 +809,7 @@ read_file_system_list (bool need_fs_type) me = xmalloc (sizeof *me); me->me_devname = xstrdup (stats[counter].f_mntfromname); me->me_mountdir = xstrdup (stats[counter].f_mntonname); + me->me_mntroot = NULL; me->me_type = xstrdup (FS_TYPE (stats[counter])); me->me_type_malloced = 1; me->me_dummy = ME_DUMMY (me->me_devname, me->me_type); @@ -833,6 +846,7 @@ read_file_system_list (bool need_fs_type) strcpy (me->me_devname + 5, mnt.mt_dev); # endif me->me_mountdir = xstrdup (mnt.mt_filsys); + me->me_mntroot = NULL; me->me_dev = (dev_t) -1; /* Magic; means not known yet. */ me->me_type = ""; me->me_type_malloced = 0; @@ -880,6 +894,7 @@ read_file_system_list (bool need_fs_type) me = xmalloc (sizeof *me); me->me_devname = xstrdup ((*ent)->mt_resource); me->me_mountdir = xstrdup ((*ent)->mt_directory); + me->me_mntroot = NULL; me->me_type = xstrdup ((*ent)->mt_fstype); me->me_type_malloced = 1; me->me_dummy = ME_DUMMY (me->me_devname, me->me_type); @@ -942,6 +957,7 @@ read_file_system_list (bool need_fs_type) me = xmalloc (sizeof *me); me->me_devname = xstrdup (mnt.mnt_special); me->me_mountdir = xstrdup (mnt.mnt_mountp); + me->me_mntroot = NULL; me->me_type = xstrdup (mnt.mnt_fstype); me->me_type_malloced = 1; me->me_dummy = MNT_IGNORE (&mnt) != 0; @@ -1020,6 +1036,7 @@ read_file_system_list (bool need_fs_type) vmp->vmt_data[VMT_OBJECT].vmt_off); } me->me_mountdir = xstrdup (thisent + vmp->vmt_data[VMT_STUB].vmt_off); + me->me_mntroot = NULL; me->me_type = xstrdup (fstype_to_string (vmp->vmt_gfstype)); me->me_type_malloced = 1; options = thisent + vmp->vmt_data[VMT_ARGS].vmt_off; @@ -1063,6 +1080,7 @@ read_file_system_list (bool need_fs_type) me = xmalloc (sizeof *me); me->me_devname = xstrdup (dev.f_mntfromname); me->me_mountdir = xstrdup (dev.f_mntonname); + me->me_mntroot = NULL; me->me_type = xstrdup (dev.f_fstypename); me->me_type_malloced = 1; me->me_dummy = ME_DUMMY (me->me_devname, me->me_type); @@ -1105,6 +1123,7 @@ void free_mount_entry (struct mount_entry *me) { free (me->me_devname); free (me->me_mountdir); + free (me->me_mntroot); if (me->me_type_malloced) free (me->me_type); free (me); diff --git a/lib/mountlist.h b/lib/mountlist.h index 735776b..9ce3137 100644 --- a/lib/mountlist.h +++ b/lib/mountlist.h @@ -27,6 +27,8 @@ struct mount_entry { char *me_devname; /* Device node name, including "/dev/". */ char *me_mountdir; /* Mount point directory name. */ + char *me_mntroot; /* Directory on filesystem of device used */ + /* as root for the (bind) mount. */ char *me_type; /* "nfs", "4.2", etc. */ dev_t me_dev; /* Device number of me_mountdir. */ unsigned int me_dummy : 1; /* Nonzero for dummy file systems. */ -- 2.5.5 From aff5e38d43f8477ccf07eb9e87a849b6c3211302 Mon Sep 17 00:00:00 2001 From: Dave Chiluk Date: Mon, 21 Sep 2015 15:04:11 -0500 Subject: [PATCH 2/2] df: prioritize mounts nearer the device root In the presence of bind mounts of a device, the 4th "mount root" field from /proc/self/mountinfo is now considered, so as to prefer mount points closer to the root of the device. Note on older systems with an /etc/mtab file, the source device was listed as the originating directory, and so this was not an issue. Details at http://pad.lv/1432871 * src/df.c (filter_mount_list): When deduplicating mount entries, only prefer sources nearer or at the root of the device, when the target is nearer the root of the device. * NEWS: Mention the change in behavior. Upstream-commit: 3babaf83875ceac896c8dd3a64248e955dfecef9 Signed-off-by: Kamil Dudka --- src/df.c | 12 +++++++++--- 1 file changed, 9 insertions(+), 3 deletions(-) diff --git a/src/df.c b/src/df.c index 0dfd554..e390298 100644 --- a/src/df.c +++ b/src/df.c @@ -649,6 +649,13 @@ filter_mount_list (bool devices_only) if (devlist) { + bool target_nearer_root = strlen (devlist->me->me_mountdir) + > strlen (me->me_mountdir); + /* With bind mounts, prefer items nearer the root of the source */ + bool source_below_root = devlist->me->me_mntroot != NULL + && me->me_mntroot != NULL + && (strlen (devlist->me->me_mntroot) + < strlen (me->me_mntroot)); if (! print_grand_total && me->me_remote && devlist->me->me_remote && ! STREQ (devlist->me->me_devname, me->me_devname)) { @@ -660,9 +667,8 @@ filter_mount_list (bool devices_only) else if ((strchr (me->me_devname, '/') /* let "real" devices with '/' in the name win. */ && ! strchr (devlist->me->me_devname, '/')) - /* let a shorter mountdir win. */ - || (strlen (devlist->me->me_mountdir) - > strlen (me->me_mountdir)) + /* let points towards the root of the device win. */ + || (target_nearer_root && ! source_below_root) /* let an entry overmounted on a new device win... */ || (! STREQ (devlist->me->me_devname, me->me_devname) /* ... but only when matching an existing mnt point, -- 2.5.5