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/ext4.h b/fs/ext4/ext4.h
index 46aaaa2ed4c5fcf4a6e5516834dd9d136af0bfb5..a004699e72961be5aaa9940b15a368b1d21c8817 100644 (file)
--- a/fs/ext4/ext4.h
+++ b/fs/ext4/ext4.h
@@ -549,7 +549,7 @@ do {                                                                               \
 #define EXT4_MOUNT_NO_UID32            0x02000  /* Disable 32-bit UIDs */
 #define EXT4_MOUNT_XATTR_USER          0x04000 /* Extended user attributes */
 #define EXT4_MOUNT_POSIX_ACL           0x08000 /* POSIX Access Control Lists */
-#define EXT4_MOUNT_RESERVATION         0x10000 /* Preallocation */
+#define EXT4_MOUNT_NO_AUTO_DA_ALLOC    0x10000 /* No auto delalloc mapping */
 #define EXT4_MOUNT_BARRIER             0x20000 /* Use block barriers */
 #define EXT4_MOUNT_NOBH                        0x40000 /* No bufferheads */
 #define EXT4_MOUNT_QUOTA               0x80000 /* Some quota option set */

diff --git a/fs/ext4/inode.c b/fs/ext4/inode.c
index d3118d1acc39608f59257b4c2a737d9a958d91a3..bed4a0abd0d13fcb42a2d058c860d1fc3a6d896a 100644 (file)
--- a/fs/ext4/inode.c
+++ b/fs/ext4/inode.c
@@ -3908,7 +3908,7 @@ void ext4_truncate(struct inode *inode)
        if (!ext4_can_truncate(inode))
                return;
 
-       if (inode->i_size == 0)
+       if (inode->i_size == 0 && !test_opt(inode->i_sb, NO_AUTO_DA_ALLOC))
                ei->i_state |= EXT4_STATE_DA_ALLOC_CLOSE;
 
        if (EXT4_I(inode)->i_flags & EXT4_EXTENTS_FL) {

diff --git a/fs/ext4/namei.c b/fs/ext4/namei.c
index eb20246c89654758f078867ad929b1a5c590b495..22098e1cd085911a7aeffc975ac7a0773a32bbc0 100644 (file)
--- a/fs/ext4/namei.c
+++ b/fs/ext4/namei.c
@@ -2497,7 +2497,8 @@ static int ext4_rename(struct inode *old_dir, struct dentry *old_dentry,
                ext4_mark_inode_dirty(handle, new_inode);
                if (!new_inode->i_nlink)
                        ext4_orphan_add(handle, new_inode);
-               force_da_alloc = 1;
+               if (!test_opt(new_dir->i_sb, NO_AUTO_DA_ALLOC))
+                       force_da_alloc = 1;
        }
        retval = 0;
 

diff --git a/fs/ext4/super.c b/fs/ext4/super.c
index b9aefceb41e786014eb42ef8655b0cdf0a7b3ce5..45d07cf9df347536c1e109943b7cc816e1465c49 100644 (file)
--- a/fs/ext4/super.c
+++ b/fs/ext4/super.c
@@ -816,8 +816,6 @@ static int ext4_show_options(struct seq_file *seq, struct vfsmount *vfs)
        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 @@ static int ext4_show_options(struct seq_file *seq, struct vfsmount *vfs)
        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 @@ enum {
        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 @@ static const match_table_t tokens = {
        {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 @@ static const match_table_t tokens = {
        {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 @@ static int parse_options(char *options, struct super_block *sb,
                               "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 @@ set_qf_format:
                        *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 @@ static int ext4_fill_super(struct super_block *sb, void *data, int silent)
        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);
 
        /*