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From 6b8fedd82c23f1d8c334c3081a1befebedc40f1f Mon Sep 17 00:00:00 2001
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From: Lennart Poettering <lennart@poettering.net>
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Date: Tue, 19 May 2015 13:50:36 +0200
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Subject: [PATCH] mount: don't claim a device is gone from /proc/self/mountinfo
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 before it is gone from *all* lines
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Devices might be referenced by multiple mount points in
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/proc/self/mountinfo, hence we should consider them unmounted only after
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they disappeared from all lines, not just from one.
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http://lists.freedesktop.org/archives/systemd-devel/2015-May/032026.html
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(cherry picked from commit fcd8b266edf0df2b85079fcf7b099cd4028740e6)
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Cherry-picked from:
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Resolves: #1222517
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---
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 src/core/mount.c | 30 +++++++++++++++++++++++++++---
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 1 file changed, 27 insertions(+), 3 deletions(-)
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diff --git a/src/core/mount.c b/src/core/mount.c
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index fd4fb6f1b..fa63f2426 100644
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--- a/src/core/mount.c
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+++ b/src/core/mount.c
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@@ -1698,7 +1698,10 @@ fail:
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 }
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 static int mount_dispatch_io(sd_event_source *source, int fd, uint32_t revents, void *userdata) {
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+        _cleanup_set_free_ Set *around = NULL, *gone = NULL;
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         Manager *m = userdata;
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+        const char *what;
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+        Iterator i;
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         Unit *u;
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         int r;
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@@ -1765,6 +1768,8 @@ static int mount_dispatch_io(sd_event_source *source, int fd, uint32_t revents,
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                 if (!mount->is_mounted) {
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+                        /* A mount point is gone */
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+
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                         mount->from_proc_self_mountinfo = false;
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                         switch (mount->state) {
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@@ -1780,13 +1785,17 @@ static int mount_dispatch_io(sd_event_source *source, int fd, uint32_t revents,
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                                 break;
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                         }
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-                        if (mount->parameters_proc_self_mountinfo.what)
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-                                (void) device_found_node(m, mount->parameters_proc_self_mountinfo.what, false, DEVICE_FOUND_MOUNT, true);
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+                        /* Remember that this device might just have disappeared */
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+                        if (mount->parameters_proc_self_mountinfo.what) {
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+                                if (set_ensure_allocated(&gone, &string_hash_ops) < 0 ||
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+                                    set_put(gone, mount->parameters_proc_self_mountinfo.what) < 0)
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+                                        log_oom(); /* we don't care too much about OOM here... */
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+                        }
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                 } else if (mount->just_mounted || mount->just_changed) {
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-                        /* New or changed mount entry */
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+                        /* A mount point was added or changed */
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                         switch (mount->state) {
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@@ -1811,12 +1820,27 @@ static int mount_dispatch_io(sd_event_source *source, int fd, uint32_t revents,
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                                 mount_set_state(mount, mount->state);
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                                 break;
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                         }
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+
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+                        if (mount->parameters_proc_self_mountinfo.what) {
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+
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+                                if (set_ensure_allocated(&around, &string_hash_ops) < 0 ||
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+                                    set_put(around, mount->parameters_proc_self_mountinfo.what) < 0)
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+                                        log_oom();
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+                        }
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                 }
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                 /* Reset the flags for later calls */
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                 mount->is_mounted = mount->just_mounted = mount->just_changed = false;
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         }
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+        SET_FOREACH(what, gone, i) {
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+                if (set_contains(around, what))
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+                        continue;
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+
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+                /* Let the device units know that the device is no longer mounted */
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+                (void) device_found_node(m, what, false, DEVICE_FOUND_MOUNT, true);
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+        }
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+
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         return 0;
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 }
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