Attachment 1458629 Details for Bug 1358887 – Patch - add master map pseudo options for mount propagation

[patch] Patch - add master map pseudo options for mount propagation

autofs-5.1.4-add-master-map-pseudo-options-for-mount-propagation.patch (text/plain), 6.53 KB, created by Ian Kent on 2018-07-13 04:36:05 UTC

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Creator: Ian Kent

Created: 2018-07-13 04:36:05 UTC

Size: 6.53 KB

patch

obsolete

>autofs-5.1.4 - add master map pseudo options for mount propagation
>
>From: Ian Kent <raven@themaw.net>
>
>Add master map entry pseudo mount option of "slave" or "private" to
>allow mount propagation of bind mounts to be set to either "slave" or
>"private".
>
>This option may be needed when using multi-mounts that have bind mounts
>that bind to a file system that is propagation shared. This is becuase
>the bind mount will have the same properties as its target which causes
>problems for offset mounts. When this happens an unwanted offset mount
>is propagated back to the target file system resulting in a deadlock
>when attempting to access the offset.
>
>By default bind mounts will inherit the mount propagation of the target
>file system.
>
>Signed-off-by: Ian Kent <raven@themaw.net>
>---
> CHANGELOG            |    1 +
> include/automount.h  |    4 ++++
> lib/master_parse.y   |   13 +++++++++++++
> lib/master_tok.l     |    2 ++
> man/auto.master.5.in |   12 ++++++++++++
> modules/mount_bind.c |   30 +++++++++++++++++++-----------
> 6 files changed, 51 insertions(+), 11 deletions(-)
>
>--- autofs-5.0.7.orig/CHANGELOG
>+++ autofs-5.0.7/CHANGELOG
>@@ -302,6 +302,7 @@
> - add units After line to include statd service.
> - use systemd sd_notify() at startup.
> - set bind mount as propagation slave.
>+- add master map pseudo options for mount propagation.
> 
> 25/07/2012 autofs-5.0.7
> =======================
>--- autofs-5.0.7.orig/include/automount.h
>+++ autofs-5.0.7/include/automount.h
>@@ -527,6 +527,10 @@ struct kernel_mod_version {
> /* Read amd map even if it's not to be ghosted (browsable) */
> #define MOUNT_FLAG_AMD_CACHE_ALL	0x0080
> 
>+/* Set mount propagation for bind mounts */
>+#define MOUNT_FLAG_SLAVE		0x0100
>+#define MOUNT_FLAG_PRIVATE		0x0200
>+
> struct autofs_point {
> 	pthread_t thid;
> 	char *path;			/* Mount point name */
>--- autofs-5.0.7.orig/lib/master_parse.y
>+++ autofs-5.0.7/lib/master_parse.y
>@@ -58,6 +58,8 @@ static char *format;
> static long timeout;
> static long negative_timeout;
> static unsigned symlnk;
>+static unsigned slave;
>+static unsigned private;
> static unsigned nobind;
> static unsigned ghost;
> extern unsigned global_selection_options;
>@@ -102,6 +104,7 @@ static int master_fprintf(FILE *, char *
> %token MAP
> %token OPT_TIMEOUT OPT_NTIMEOUT OPT_NOBIND OPT_NOGHOST OPT_GHOST OPT_VERBOSE
> %token OPT_DEBUG OPT_RANDOM OPT_USE_WEIGHT OPT_SYMLINK
>+%token OPT_SLAVE OPT_PRIVATE
> %token COLON COMMA NL DDASH
> %type <strtype> map
> %type <strtype> options
>@@ -188,6 +191,8 @@ line:
> 	| PATH OPT_DEBUG { master_notify($1); YYABORT; }
> 	| PATH OPT_TIMEOUT { master_notify($1); YYABORT; }
> 	| PATH OPT_SYMLINK { master_notify($1); YYABORT; }
>+	| PATH OPT_SLAVE { master_notify($1); YYABORT; }
>+	| PATH OPT_PRIVATE { master_notify($1); YYABORT; }
> 	| PATH OPT_NOBIND { master_notify($1); YYABORT; }
> 	| PATH OPT_GHOST { master_notify($1); YYABORT; }
> 	| PATH OPT_NOGHOST { master_notify($1); YYABORT; }
>@@ -569,6 +574,8 @@ option: daemon_option
> daemon_option: OPT_TIMEOUT NUMBER { timeout = $2; }
> 	| OPT_NTIMEOUT NUMBER { negative_timeout = $2; }
> 	| OPT_SYMLINK	{ symlnk = 1; }
>+	| OPT_SLAVE	{ slave = 1; }
>+	| OPT_PRIVATE	{ private = 1; }
> 	| OPT_NOBIND	{ nobind = 1; }
> 	| OPT_NOGHOST	{ ghost = 0; }
> 	| OPT_GHOST	{ ghost = 1; }
>@@ -640,6 +647,8 @@ static void local_init_vars(void)
> 	timeout = -1;
> 	negative_timeout = 0;
> 	symlnk = 0;
>+	slave = 0;
>+	private = 0;
> 	nobind = 0;
> 	ghost = defaults_get_browse_mode();
> 	random_selection = global_selection_options & MOUNT_FLAG_RANDOM_SELECT;
>@@ -845,6 +854,10 @@ int master_parse_entry(const char *buffe
> 		entry->ap->flags |= MOUNT_FLAG_USE_WEIGHT_ONLY;
> 	if (symlnk)
> 		entry->ap->flags |= MOUNT_FLAG_SYMLINK;
>+	if (slave)
>+		entry->ap->flags |= MOUNT_FLAG_SLAVE;
>+	if (private)
>+		entry->ap->flags |= MOUNT_FLAG_PRIVATE;
> 	if (negative_timeout)
> 		entry->ap->negative_timeout = negative_timeout;
> 
>--- autofs-5.0.7.orig/lib/master_tok.l
>+++ autofs-5.0.7/lib/master_tok.l
>@@ -386,6 +386,8 @@ OPTNTOUT	(-n{OPTWS}|-n{OPTWS}={OPTWS}|--
> 	-?symlink		{ return(OPT_SYMLINK); }
> 	-?nobind		{ return(OPT_NOBIND); }
> 	-?nobrowse		{ return(OPT_NOGHOST); }
>+	-?slave			{ return(OPT_SLAVE); }
>+	-?private		{ return(OPT_PRIVATE); }
> 	-g|--ghost|-?browse	{ return(OPT_GHOST); }
> 	-v|--verbose		{ return(OPT_VERBOSE); }
> 	-d|--debug		{ return(OPT_DEBUG); }
>--- autofs-5.0.7.orig/man/auto.master.5.in
>+++ autofs-5.0.7/man/auto.master.5.in
>@@ -198,6 +198,18 @@ entries only, either in the master map (
> or with individual map entries. The option is ignored for direct mounts
> and non-root offest mount entries.
> .TP
>+.I slave \fPor\fI private
>+This option allows mount propagation of bind mounts to be set to
>+either \fIslave\fP or \fIprivate\fP. This option may be needed when using
>+multi-mounts that have bind mounts that bind to a file system that is
>+propagation shared. This is becuase the bind mount will have the same
>+properties as its target which causes problems for offset mounts. When
>+this happens an unwanted offset mount is propagated back to the target
>+file system resulting in a deadlock when attempting to access the offset.
>+This option is a an autofs pseudo mount option that can be used in the
>+master map only. By default bind mounts will inherit the mount propagation
>+of the target file system.
>+.TP
> .I "\-r, \-\-random-multimount-selection"
> Enables the use of ramdom selection when choosing a host from a
> list of replicated servers. This option is applied to this mount
>--- autofs-5.0.7.orig/modules/mount_bind.c
>+++ autofs-5.0.7/modules/mount_bind.c
>@@ -187,17 +187,25 @@ int mount_mount(struct autofs_point *ap,
> 			      what, fstype, fullpath);
> 		}
> 
>-		/* The bind mount has succeeded but if the target
>-		 * mount is propagation shared propagation of child
>-		 * mounts (autofs offset mounts for example) back to
>-		 * the target of the bind mount must be avoided or
>-		 * autofs trigger mounts will deadlock.
>-		 */
>-		err = mount(NULL, fullpath, NULL, MS_SLAVE, NULL);
>-		if (err)
>-			warn(ap->logopt,
>-			     "failed to set propagation type for %s",
>-			     fullpath);
>+		if (ap->flags & (MOUNT_FLAG_SLAVE | MOUNT_FLAG_PRIVATE)) {
>+			int flags = MS_SLAVE;
>+
>+			if (ap->flags & MOUNT_FLAG_PRIVATE)
>+				flags = MS_PRIVATE;
>+
>+			/* The bind mount has succeeded but if the target
>+			 * mount is propagation shared propagation of child
>+			 * mounts (autofs offset mounts for example) back to
>+			 * the target of the bind mount must be avoided or
>+			 * autofs trigger mounts will deadlock.
>+			 */
>+			err = mount(NULL, fullpath, NULL, flags, NULL);
>+			if (err) {
>+				warn(ap->logopt,
>+				     "failed to set propagation for %s",
>+				     fullpath, root);
>+			}
>+		}
> 
> 		return 0;
> 	} else {

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Attachments on bug 1358887: 1458628 | 1458629