ext4: Add auto_da_alloc mount option
Add a mount option which allows the user to disable automatic
allocation of blocks whose allocation by delayed allocation when the
file was originally truncated or when the file is renamed over an
existing file. This feature is intended to save users from the
effects of naive application writers, but it reduces the effectiveness
of the delayed allocation code. This mount option disables this
safety feature, which may be desirable for prodcutions systems where
the risk of unclean shutdowns or unexpected system crashes is low.
Signed-off-by: "Theodore Ts'o" <tytso@mit.edu>
diff --git a/fs/ext4/super.c b/fs/ext4/super.c
index b9aefce..45d07cf 100644
--- a/fs/ext4/super.c
+++ b/fs/ext4/super.c
@@ -816,8 +816,6 @@
if (!test_opt(sb, POSIX_ACL) && (def_mount_opts & EXT4_DEFM_ACL))
seq_puts(seq, ",noacl");
#endif
- if (!test_opt(sb, RESERVATION))
- seq_puts(seq, ",noreservation");
if (sbi->s_commit_interval != JBD2_DEFAULT_MAX_COMMIT_AGE*HZ) {
seq_printf(seq, ",commit=%u",
(unsigned) (sbi->s_commit_interval / HZ));
@@ -868,6 +866,9 @@
if (test_opt(sb, DATA_ERR_ABORT))
seq_puts(seq, ",data_err=abort");
+ if (test_opt(sb, NO_AUTO_DA_ALLOC))
+ seq_puts(seq, ",auto_da_alloc=0");
+
ext4_show_quota_options(seq, sb);
return 0;
}
@@ -1017,7 +1018,7 @@
Opt_resgid, Opt_resuid, Opt_sb, Opt_err_cont, Opt_err_panic, Opt_err_ro,
Opt_nouid32, Opt_debug, Opt_oldalloc, Opt_orlov,
Opt_user_xattr, Opt_nouser_xattr, Opt_acl, Opt_noacl,
- Opt_reservation, Opt_noreservation, Opt_noload, Opt_nobh, Opt_bh,
+ Opt_auto_da_alloc, Opt_noload, Opt_nobh, Opt_bh,
Opt_commit, Opt_min_batch_time, Opt_max_batch_time,
Opt_journal_update, Opt_journal_dev,
Opt_journal_checksum, Opt_journal_async_commit,
@@ -1052,8 +1053,6 @@
{Opt_nouser_xattr, "nouser_xattr"},
{Opt_acl, "acl"},
{Opt_noacl, "noacl"},
- {Opt_reservation, "reservation"},
- {Opt_noreservation, "noreservation"},
{Opt_noload, "noload"},
{Opt_nobh, "nobh"},
{Opt_bh, "bh"},
@@ -1088,6 +1087,7 @@
{Opt_nodelalloc, "nodelalloc"},
{Opt_inode_readahead_blks, "inode_readahead_blks=%u"},
{Opt_journal_ioprio, "journal_ioprio=%u"},
+ {Opt_auto_da_alloc, "auto_da_alloc=%u"},
{Opt_err, NULL},
};
@@ -1220,12 +1220,6 @@
"not supported\n");
break;
#endif
- case Opt_reservation:
- set_opt(sbi->s_mount_opt, RESERVATION);
- break;
- case Opt_noreservation:
- clear_opt(sbi->s_mount_opt, RESERVATION);
- break;
case Opt_journal_update:
/* @@@ FIXME */
/* Eventually we will want to be able to create
@@ -1491,6 +1485,14 @@
*journal_ioprio = IOPRIO_PRIO_VALUE(IOPRIO_CLASS_BE,
option);
break;
+ case Opt_auto_da_alloc:
+ if (match_int(&args[0], &option))
+ return 0;
+ if (option)
+ clear_opt(sbi->s_mount_opt, NO_AUTO_DA_ALLOC);
+ else
+ set_opt(sbi->s_mount_opt,NO_AUTO_DA_ALLOC);
+ break;
default:
printk(KERN_ERR
"EXT4-fs: Unrecognized mount option \"%s\" "
@@ -2306,7 +2308,6 @@
sbi->s_min_batch_time = EXT4_DEF_MIN_BATCH_TIME;
sbi->s_max_batch_time = EXT4_DEF_MAX_BATCH_TIME;
- set_opt(sbi->s_mount_opt, RESERVATION);
set_opt(sbi->s_mount_opt, BARRIER);
/*