diff options
Diffstat (limited to 'fs/super.c')
| -rw-r--r-- | fs/super.c | 30 |
1 files changed, 24 insertions, 6 deletions
diff --git a/fs/super.c b/fs/super.c index aff046b0fe7..1527e6a0ee3 100644 --- a/fs/super.c +++ b/fs/super.c @@ -37,6 +37,7 @@ #include <linux/kobject.h> #include <linux/mutex.h> #include <linux/file.h> +#include <linux/backing-dev.h> #include <asm/uaccess.h> #include "internal.h" @@ -568,7 +569,7 @@ out: int do_remount_sb(struct super_block *sb, int flags, void *data, int force) { int retval; - int remount_rw; + int remount_rw, remount_ro; if (sb->s_frozen != SB_UNFROZEN) return -EBUSY; @@ -583,9 +584,12 @@ int do_remount_sb(struct super_block *sb, int flags, void *data, int force) shrink_dcache_sb(sb); sync_filesystem(sb); + remount_ro = (flags & MS_RDONLY) && !(sb->s_flags & MS_RDONLY); + remount_rw = !(flags & MS_RDONLY) && (sb->s_flags & MS_RDONLY); + /* If we are remounting RDONLY and current sb is read/write, make sure there are no rw files opened */ - if ((flags & MS_RDONLY) && !(sb->s_flags & MS_RDONLY)) { + if (remount_ro) { if (force) mark_files_ro(sb); else if (!fs_may_remount_ro(sb)) @@ -594,7 +598,6 @@ int do_remount_sb(struct super_block *sb, int flags, void *data, int force) if (retval < 0 && retval != -ENOSYS) return -EBUSY; } - remount_rw = !(flags & MS_RDONLY) && (sb->s_flags & MS_RDONLY); if (sb->s_op->remount_fs) { retval = sb->s_op->remount_fs(sb, &flags, data); @@ -604,6 +607,16 @@ int do_remount_sb(struct super_block *sb, int flags, void *data, int force) sb->s_flags = (sb->s_flags & ~MS_RMT_MASK) | (flags & MS_RMT_MASK); if (remount_rw) vfs_dq_quota_on_remount(sb); + /* + * Some filesystems modify their metadata via some other path than the + * bdev buffer cache (eg. use a private mapping, or directories in + * pagecache, etc). Also file data modifications go via their own + * mappings. So If we try to mount readonly then copy the filesystem + * from bdev, we could get stale data, so invalidate it to give a best + * effort at coherency. + */ + if (remount_ro && sb->s_bdev) + invalidate_bdev(sb->s_bdev); return 0; } @@ -681,6 +694,7 @@ int set_anon_super(struct super_block *s, void *data) return -EMFILE; } s->s_dev = MKDEV(0, dev & MINORMASK); + s->s_bdi = &noop_backing_dev_info; return 0; } @@ -925,6 +939,9 @@ vfs_kern_mount(struct file_system_type *type, int flags, const char *name, void if (!mnt) goto out; + if (flags & MS_KERNMOUNT) + mnt->mnt_flags = MNT_INTERNAL; + if (data && !(type->fs_flags & FS_BINARY_MOUNTDATA)) { secdata = alloc_secdata(); if (!secdata) @@ -939,10 +956,11 @@ vfs_kern_mount(struct file_system_type *type, int flags, const char *name, void if (error < 0) goto out_free_secdata; BUG_ON(!mnt->mnt_sb); + WARN_ON(!mnt->mnt_sb->s_bdi); - error = security_sb_kern_mount(mnt->mnt_sb, flags, secdata); - if (error) - goto out_sb; + error = security_sb_kern_mount(mnt->mnt_sb, flags, secdata); + if (error) + goto out_sb; /* * filesystems should never set s_maxbytes larger than MAX_LFS_FILESIZE |