libmount: use some MS_* flags as superblock flags

The old mount(2) API usually utilizes MS_* flags to set up the VFS
node. However, there are some exceptions like "sync" (MS_SYNCHRONOUS),
where the flag is used (by kernel) for the superblock instead. The new
API addresses this issue, ensuring that these options are used for
fsconfig().

This commit introduces MNT_SUPERBLOCK to identify these options in the
libmount options Linux map, and it enforces the new mount code to
utilize these options for fsconfig(FSCONFIG_SET_FLAG).

Reported-by: Abbink Esger <esger.abbink.ext@siemens.com>
Signed-off-by: Karel Zak <kzak@redhat.com>

diff --git a/libmount/src/hook_mount.c b/libmount/src/hook_mount.c
index 77a7bed309bcb8a50272685b0f3cc999eaba4c65..ed4ec349ca32fe93c02b5dcbe78b5189710e2e80 100644 (file)
--- a/libmount/src/hook_mount.c
+++ b/libmount/src/hook_mount.c
@@ -154,12 +154,19 @@ static int configure_superblock(struct libmnt_context *cxt,
                const char *name = mnt_opt_get_name(opt);
                const char *value = mnt_opt_get_value(opt);
                const struct libmnt_optmap *ent = mnt_opt_get_mapent(opt);
+               const int is_linux = ent && mnt_opt_get_map(opt) == cxt->map_linux;
 
-               if (ent && mnt_opt_get_map(opt) == cxt->map_linux &&
-                   ent->id == MS_RDONLY) {
+               if (is_linux && ent->id == MS_RDONLY) {
+                       /* Use ro/rw for superblock (for backward compatibility) */
                        value = NULL;
                        has_rwro = 1;
+
+               } else if (is_linux && ent->mask & MNT_SUPERBLOCK) {
+                       /* Use some old MS_* (VFS) flags as superblock flags */
+                       ;
+
                } else if (!name || mnt_opt_get_map(opt) || mnt_opt_is_external(opt))
+                       /* Ignore VFS flags, userspace and external options */
                        continue;
 
                rc = fsconfig_set_value(cxt, hs, fd, name, value);

diff --git a/libmount/src/libmount.h.in b/libmount/src/libmount.h.in
index f156483b6eeeb6eaedc40d0b3cec58e8d1344f4d..06c27047d2dfd5151376681ba433c685652f414a 100644 (file)
--- a/libmount/src/libmount.h.in
+++ b/libmount/src/libmount.h.in
@@ -89,6 +89,7 @@ struct libmnt_optmap
 #define MNT_PREFIX     (1 << 3) /* prefix used for some options (e.g. "x-foo") */
 #define MNT_NOHLPS     (1 << 4) /* don't add the option to mount.<type> helpers command line */
 #define MNT_NOFSTAB    (1 << 5) /* not expected in fstab */
+#define MNT_SUPERBLOCK (1 << 6) /* MS_* for mount(2), otherwise requires fsconfig() */
 
 /**
  * libmnt_fs:

diff --git a/libmount/src/optmap.c b/libmount/src/optmap.c
index 3a91f30d4177a1ee7e450c7f79def531c80b787c..d7569a0f0380ab15b29e6c01ce9bcf1af077eda7 100644 (file)
--- a/libmount/src/optmap.c
+++ b/libmount/src/optmap.c
@@ -79,10 +79,10 @@ static const struct libmnt_optmap linux_flags_map[] =
    { "dev",      MS_NODEV, MNT_INVERT },      /* interpret device files  */
    { "nodev",    MS_NODEV },                  /* don't interpret devices */
 
-   { "sync",     MS_SYNCHRONOUS },            /* synchronous I/O */
-   { "async",    MS_SYNCHRONOUS, MNT_INVERT },/* asynchronous I/O */
+   { "sync",     MS_SYNCHRONOUS, MNT_SUPERBLOCK },            /* synchronous I/O */
+   { "async",    MS_SYNCHRONOUS, MNT_INVERT | MNT_SUPERBLOCK },/* asynchronous I/O */
 
-   { "dirsync",  MS_DIRSYNC },                /* synchronous directory modifications */
+   { "dirsync",  MS_DIRSYNC, MNT_SUPERBLOCK },/* synchronous directory modifications */
    { "remount",  MS_REMOUNT, MNT_NOMTAB },    /* alter flags of mounted FS */
    { "bind",     MS_BIND },                   /* Remount part of the tree elsewhere */
    { "rbind",    MS_BIND | MS_REC },          /* Idem, plus mounted subtrees */
@@ -95,8 +95,8 @@ static const struct libmnt_optmap linux_flags_map[] =
    { "loud",     MS_SILENT, MNT_INVERT },     /* print out messages. */
 #endif
 #ifdef MS_MANDLOCK
-   { "mand",     MS_MANDLOCK },               /* Allow mandatory locks on this FS */
-   { "nomand",   MS_MANDLOCK, MNT_INVERT },   /* Forbid mandatory locks on this FS */
+   { "mand",     MS_MANDLOCK, MNT_SUPERBLOCK },               /* Allow mandatory locks on this FS */
+   { "nomand",   MS_MANDLOCK, MNT_INVERT | MNT_SUPERBLOCK},   /* Forbid mandatory locks on this FS */
 #endif
 #ifdef MS_NOATIME
    { "atime",    MS_NOATIME, MNT_INVERT },    /* Update access time */
@@ -119,8 +119,8 @@ static const struct libmnt_optmap linux_flags_map[] =
    { "nostrictatime", MS_STRICTATIME, MNT_INVERT }, /* kernel default atime */
 #endif
 #ifdef MS_LAZYTIME
-   { "lazytime", MS_LAZYTIME },               /* Update {a,m,c}time on the in-memory inode only */
-   { "nolazytime", MS_LAZYTIME, MNT_INVERT },
+   { "lazytime", MS_LAZYTIME, MNT_SUPERBLOCK },               /* Update {a,m,c}time on the in-memory inode only */
+   { "nolazytime", MS_LAZYTIME, MNT_INVERT | MNT_SUPERBLOCK },
 #endif
 #ifdef MS_PROPAGATION
    { "unbindable",  MS_UNBINDABLE,          MNT_NOHLPS | MNT_NOMTAB }, /* Unbindable */