From 0f66811659aa8fd8b14ade8a80bfecd580962b2d Mon Sep 17 00:00:00 2001 From: Karel Zak Date: Tue, 10 Mar 2015 12:51:44 +0100 Subject: [PATCH 71/84] findmnt: don't rely on st_dev for --target The overlay filesystem does not provide usable st_dev (in traditional UNIX way). It's necessary to search in /proc/self/mountinfo to detect which path element is mountpoint. $ findmnt --target /mnt/merged/dir-a/foo TARGET SOURCE FSTYPE OPTIONS /mnt/merged overlay overlay rw,relatime,lowerdir=/mnt/low,upperdir=/mnt/high/data,workdir=/mnt/high/work Upstream: http://github.com/karelzak/util-linux/commit/cd41b385a06dde70bb45c3143d3459157bda58f8 Addresses: http://bugzilla.redhat.com/show_bug.cgi?id=587393 Signed-off-by: Karel Zak --- libmount/src/utils.c | 6 +++++- misc-utils/findmnt.8 | 8 ++++++-- misc-utils/findmnt.c | 17 +++++++++++------ 3 files changed, 22 insertions(+), 9 deletions(-) diff --git a/libmount/src/utils.c b/libmount/src/utils.c index 7c6f5b1..5783d88 100644 --- a/libmount/src/utils.c +++ b/libmount/src/utils.c @@ -859,7 +859,11 @@ int mnt_open_uniq_filename(const char *filename, char **name) * This function finds the mountpoint that a given path resides in. @path * should be canonicalized. The returned pointer should be freed by the caller. * - * Returns: allocated string with target of the mounted device or NULL on error + * WARNING: the function compares st_dev of the @path elements. This traditional + * way maybe be insufficient on filesystems like Linux "overlay". See also + * mnt_table_find_target(). + * + * Returns: allocated string with the target of the mounted device or NULL on error */ char *mnt_get_mountpoint(const char *path) { diff --git a/misc-utils/findmnt.8 b/misc-utils/findmnt.8 index 407636e..54739b7 100644 --- a/misc-utils/findmnt.8 +++ b/misc-utils/findmnt.8 @@ -179,8 +179,12 @@ Search in .IR /etc/fstab . The output is in the list format (see \fB--list\fR). .TP -.BR \-T , " \-\-target \fIdir\fP" -Explicitly define the mount target (mountpoint directory). +.BR \-T , " \-\-target \fIpath\fP" +Explicitly define the mount target (mountpoint directory). If the \fIpath\fR +is not a mountpoint file or directory than +.B findmnt +checks \fIpath\fR elements in reverse order for get the mountpoint (this feature is +supported only if search in kernel files and unsupported for \fB\-\-fstab\fP). .TP .BR \-t , " \-\-types \fIlist\fP" Limit the set of printed filesystems. More than one type may be diff --git a/misc-utils/findmnt.c b/misc-utils/findmnt.c index f16da91..fe899db 100644 --- a/misc-utils/findmnt.c +++ b/misc-utils/findmnt.c @@ -236,9 +236,12 @@ static void set_source_match(const char *data) set_match(COL_SOURCE, data); } -static void enable_extra_target_match(void) +/* @tb has to be from kernel (so no fstab or so)! */ +static void enable_extra_target_match(struct libmnt_table *tb) { - char *cn = NULL, *mnt = NULL; + char *cn = NULL; + const char *tgt = NULL, *mnt = NULL; + struct libmnt_fs *fs; /* * Check if match pattern is mountpoint, if not use the @@ -248,9 +251,11 @@ static void enable_extra_target_match(void) if (!cn) return; - mnt = mnt_get_mountpoint(cn); - if (!mnt || strcmp(mnt, cn) == 0) - return; + fs = mnt_table_find_mountpoint(tb, tgt, MNT_ITER_BACKWARD); + if (fs) + mnt = mnt_fs_get_target(fs); + if (mnt && strcmp(mnt, tgt) != 0) + set_match(COL_TARGET, xstrdup(mnt)); /* replace the current setting */ /* replace the current setting with the real mountpoint */ set_match(COL_TARGET, mnt); @@ -1484,7 +1489,7 @@ int main(int argc, char *argv[]) * try it again with extra functionality for target * match */ - enable_extra_target_match(); + enable_extra_target_match(tb); rc = add_matching_lines(tb, tt, direction); } } -- 2.7.4