nilfs2: add norecovery mount option
This adds "norecovery" mount option which disables temporal write
access to read-only mounts or snapshots during mount/recovery.
Without this option, write access will be even performed for those
types of mounts; the temporal write access is needed to mount root
file system read-only after an unclean shutdown.
This option will be helpful when user wants to prevent any write
access to the device.
Signed-off-by: Ryusuke Konishi <konishi.ryusuke@lab.ntt.co.jp>
Cc: Eric Sandeen <sandeen@redhat.com>
diff --git a/fs/nilfs2/the_nilfs.c b/fs/nilfs2/the_nilfs.c
index 890a8d3..6241e17 100644
--- a/fs/nilfs2/the_nilfs.c
+++ b/fs/nilfs2/the_nilfs.c
@@ -264,8 +264,14 @@
int valid_fs = nilfs_valid_fs(nilfs);
int err;
- if (nilfs_loaded(nilfs))
- return 0;
+ if (nilfs_loaded(nilfs)) {
+ if (valid_fs ||
+ ((s_flags & MS_RDONLY) && nilfs_test_opt(sbi, NORECOVERY)))
+ return 0;
+ printk(KERN_ERR "NILFS: the filesystem is in an incomplete "
+ "recovery state.\n");
+ return -EINVAL;
+ }
if (!valid_fs) {
printk(KERN_WARNING "NILFS warning: mounting unchecked fs\n");
@@ -295,6 +301,11 @@
goto skip_recovery;
if (s_flags & MS_RDONLY) {
+ if (nilfs_test_opt(sbi, NORECOVERY)) {
+ printk(KERN_INFO "NILFS: norecovery option specified. "
+ "skipping roll-forward recovery\n");
+ goto skip_recovery;
+ }
if (really_read_only) {
printk(KERN_ERR "NILFS: write access "
"unavailable, cannot proceed.\n");
@@ -302,6 +313,11 @@
goto failed_unload;
}
sbi->s_super->s_flags &= ~MS_RDONLY;
+ } else if (nilfs_test_opt(sbi, NORECOVERY)) {
+ printk(KERN_ERR "NILFS: recovery cancelled because norecovery "
+ "option was specified for a read/write mount\n");
+ err = -EINVAL;
+ goto failed_unload;
}
err = nilfs_recover_logical_segments(nilfs, sbi, &ri);