The patch titled
vfs: mark mounts read-only on forced remount
has been added to the -mm tree. Its filename is
vfs-mark-mounts-read-only-on-forced-remount.patch
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------------------------------------------------------
Subject: vfs: mark mounts read-only on forced remount
From: Miklos Szeredi <mszeredi@xxxxxxx>
When the superblock is forcefully remounted read-only, as in case of an
emergency remount or filesystem errors, make sure that the mounts
belonging to the superblock are also marked read-only.
Signed-off-by: Miklos Szeredi <mszeredi@xxxxxxx>
Cc: Al Viro <viro@xxxxxxxxxxxxxxxxxx>
Cc: Christoph Hellwig <hch@xxxxxx>
Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
---
fs/internal.h | 1 +
fs/namespace.c | 16 ++++++++++++++++
fs/super.c | 16 ++++++++++++----
3 files changed, 29 insertions(+), 4 deletions(-)
diff -puN fs/internal.h~vfs-mark-mounts-read-only-on-forced-remount fs/internal.h
--- a/fs/internal.h~vfs-mark-mounts-read-only-on-forced-remount
+++ a/fs/internal.h
@@ -72,6 +72,7 @@ extern struct vfsmount *copy_tree(struct
extern int sb_prepare_remount_readonly(struct super_block *);
extern void sb_cancel_remount_readonly(struct super_block *);
extern void sb_finish_remount_readonly(struct super_block *);
+extern void mark_mounts_readonly(struct super_block *);
extern void __init mnt_init(void);
diff -puN fs/namespace.c~vfs-mark-mounts-read-only-on-forced-remount fs/namespace.c
--- a/fs/namespace.c~vfs-mark-mounts-read-only-on-forced-remount
+++ a/fs/namespace.c
@@ -418,7 +418,13 @@ static int mnt_make_writable(struct vfsm
void sb_force_remount_readonly(struct super_block *sb)
{
+ struct vfsmount *mnt;
+
+ br_write_lock(vfsmount_lock);
+ list_for_each_entry(mnt, &sb->s_mounts, mnt_instance)
+ mnt->mnt_flags |= MNT_READONLY;
sb->s_flags |= MS_RDONLY;
+ br_write_unlock(vfsmount_lock);
}
EXPORT_SYMBOL(sb_force_remount_readonly);
@@ -477,6 +483,16 @@ void sb_finish_remount_readonly(struct s
wake_up_all(&sb->s_wait_remount_readonly);
}
+void mark_mounts_readonly(struct super_block *sb)
+{
+ struct vfsmount *mnt;
+
+ br_write_lock(vfsmount_lock);
+ list_for_each_entry(mnt, &sb->s_mounts, mnt_instance)
+ mnt->mnt_flags |= MNT_READONLY;
+ br_write_unlock(vfsmount_lock);
+}
+
void simple_set_mnt(struct vfsmount *mnt, struct super_block *sb)
{
mnt->mnt_sb = sb;
diff -puN fs/super.c~vfs-mark-mounts-read-only-on-forced-remount fs/super.c
--- a/fs/super.c~vfs-mark-mounts-read-only-on-forced-remount
+++ a/fs/super.c
@@ -558,6 +558,7 @@ int do_remount_sb(struct super_block *sb
{
int retval;
int remount_ro;
+ bool old_ro;
if (sb->s_frozen != SB_UNFROZEN)
return -EBUSY;
@@ -572,12 +573,14 @@ int do_remount_sb(struct super_block *sb
shrink_dcache_sb(sb);
sync_filesystem(sb);
- remount_ro = (flags & MS_RDONLY) && !(sb->s_flags & MS_RDONLY);
+ old_ro = (sb->s_flags & MS_RDONLY) != 0;
+ remount_ro = (flags & MS_RDONLY) && !old_ro;
/* If we are remounting RDONLY and current sb is read/write,
make sure there are no rw files opened */
if (remount_ro) {
if (force) {
+ mark_mounts_readonly(sb);
mark_files_ro(sb);
} else {
retval = sb_prepare_remount_readonly(sb);
@@ -599,9 +602,14 @@ int do_remount_sb(struct super_block *sb
return retval;
}
}
- if (remount_ro && !force)
- sb_finish_remount_readonly(sb);
-
+ if (remount_ro) {
+ WARN_ON(!(flags & MS_RDONLY));
+ if (!force)
+ sb_finish_remount_readonly(sb);
+ } else if ((flags & MS_RDONLY) && !old_ro) {
+ /* filesystem remounted r/o without being asked to */
+ sb_force_remount_readonly(sb);
+ }
sb->s_flags = (sb->s_flags & ~MS_RMT_MASK) | (flags & MS_RMT_MASK);
/*
_
Patches currently in -mm which might be from mszeredi@xxxxxxx are
linux-next.patch
vfs-fix-infinite-loop-caused-by-clone_mnt-race.patch
vfs-ignore-error-on-forced-remount.patch
vfs-fix-per-mount-read-write.patch
vfs-add-sb_force_remount_readonly-helper.patch
vfs-allow-mnt_want_write-to-sleep.patch
vfs-allow-mnt_want_write-to-sleep-fix.patch
vfs-keep-list-of-mounts-for-each-superblock.patch
vfs-protect-remounting-superblock-read-only.patch
vfs-fs_may_remount_ro-turn-unnecessary-check-into-a-warn_on.patch
vfs-mark-mounts-read-only-on-forced-remount.patch
fuse-use-clear_highpage-and-km_user0-instead-of-km_user1.patch
fuse-use-release_pages.patch
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