diff options
Diffstat (limited to 'fs/super.c')
| -rw-r--r-- | fs/super.c | 107 |
1 files changed, 73 insertions, 34 deletions
diff --git a/fs/super.c b/fs/super.c index 11e2a6cb3baf..50553233dd15 100644 --- a/fs/super.c +++ b/fs/super.c @@ -836,28 +836,35 @@ rescan: } /** - * do_remount_sb - asks filesystem to change mount options. - * @sb: superblock in question - * @sb_flags: revised superblock flags - * @data: the rest of options - * @force: whether or not to force the change + * reconfigure_super - asks filesystem to change superblock parameters + * @fc: The superblock and configuration * - * Alters the mount options of a mounted file system. + * Alters the configuration parameters of a live superblock. */ -int do_remount_sb(struct super_block *sb, int sb_flags, void *data, int force) +int reconfigure_super(struct fs_context *fc) { + struct super_block *sb = fc->root->d_sb; int retval; - int remount_ro; + bool remount_ro = false; + bool force = fc->sb_flags & SB_FORCE; + if (fc->sb_flags_mask & ~MS_RMT_MASK) + return -EINVAL; if (sb->s_writers.frozen != SB_UNFROZEN) return -EBUSY; + retval = security_sb_remount(sb, fc->security); + if (retval) + return retval; + + if (fc->sb_flags_mask & SB_RDONLY) { #ifdef CONFIG_BLOCK - if (!(sb_flags & SB_RDONLY) && bdev_read_only(sb->s_bdev)) - return -EACCES; + if (!(fc->sb_flags & SB_RDONLY) && bdev_read_only(sb->s_bdev)) + return -EACCES; #endif - remount_ro = (sb_flags & SB_RDONLY) && !sb_rdonly(sb); + remount_ro = (fc->sb_flags & SB_RDONLY) && !sb_rdonly(sb); + } if (remount_ro) { if (!hlist_empty(&sb->s_pins)) { @@ -868,13 +875,14 @@ int do_remount_sb(struct super_block *sb, int sb_flags, void *data, int force) return 0; if (sb->s_writers.frozen != SB_UNFROZEN) return -EBUSY; - remount_ro = (sb_flags & SB_RDONLY) && !sb_rdonly(sb); + remount_ro = !sb_rdonly(sb); } } shrink_dcache_sb(sb); - /* If we are remounting RDONLY and current sb is read/write, - make sure there are no rw files opened */ + /* If we are reconfiguring to RDONLY and current sb is read/write, + * make sure there are no files open for writing. + */ if (remount_ro) { if (force) { sb->s_readonly_remount = 1; @@ -886,17 +894,17 @@ int do_remount_sb(struct super_block *sb, int sb_flags, void *data, int force) } } - if (sb->s_op->remount_fs) { - retval = sb->s_op->remount_fs(sb, &sb_flags, data); - if (retval) { - if (!force) - goto cancel_readonly; - /* If forced remount, go ahead despite any errors */ - WARN(1, "forced remount of a %s fs returned %i\n", - sb->s_type->name, retval); - } + retval = legacy_reconfigure(fc); + if (retval) { + if (!force) + goto cancel_readonly; + /* If forced remount, go ahead despite any errors */ + WARN(1, "forced remount of a %s fs returned %i\n", + sb->s_type->name, retval); } - sb->s_flags = (sb->s_flags & ~MS_RMT_MASK) | (sb_flags & MS_RMT_MASK); + + WRITE_ONCE(sb->s_flags, ((sb->s_flags & ~fc->sb_flags_mask) | + (fc->sb_flags & fc->sb_flags_mask))); /* Needs to be ordered wrt mnt_is_readonly() */ smp_wmb(); sb->s_readonly_remount = 0; @@ -923,10 +931,15 @@ static void do_emergency_remount_callback(struct super_block *sb) down_write(&sb->s_umount); if (sb->s_root && sb->s_bdev && (sb->s_flags & SB_BORN) && !sb_rdonly(sb)) { - /* - * What lock protects sb->s_flags?? - */ - do_remount_sb(sb, SB_RDONLY, NULL, 1); + struct fs_context *fc; + + fc = fs_context_for_reconfigure(sb->s_root, + SB_RDONLY | SB_FORCE, SB_RDONLY); + if (!IS_ERR(fc)) { + if (parse_monolithic_mount_data(fc, NULL) == 0) + (void)reconfigure_super(fc); + put_fs_context(fc); + } } up_write(&sb->s_umount); } @@ -1213,6 +1226,31 @@ struct dentry *mount_nodev(struct file_system_type *fs_type, } EXPORT_SYMBOL(mount_nodev); +static int reconfigure_single(struct super_block *s, + int flags, void *data) +{ + struct fs_context *fc; + int ret; + + /* The caller really need to be passing fc down into mount_single(), + * then a chunk of this can be removed. [Bollocks -- AV] + * Better yet, reconfiguration shouldn't happen, but rather the second + * mount should be rejected if the parameters are not compatible. + */ + fc = fs_context_for_reconfigure(s->s_root, flags, MS_RMT_MASK); + if (IS_ERR(fc)) + return PTR_ERR(fc); + + ret = parse_monolithic_mount_data(fc, data); + if (ret < 0) + goto out; + + ret = reconfigure_super(fc); +out: + put_fs_context(fc); + return ret; +} + static int compare_single(struct super_block *s, void *p) { return 1; @@ -1230,13 +1268,14 @@ struct dentry *mount_single(struct file_system_type *fs_type, return ERR_CAST(s); if (!s->s_root) { error = fill_super(s, data, flags & SB_SILENT ? 1 : 0); - if (error) { - deactivate_locked_super(s); - return ERR_PTR(error); - } - s->s_flags |= SB_ACTIVE; + if (!error) + s->s_flags |= SB_ACTIVE; } else { - do_remount_sb(s, flags, data, 0); + error = reconfigure_single(s, flags, data); + } + if (unlikely(error)) { + deactivate_locked_super(s); + return ERR_PTR(error); } return dget(s->s_root); } |