ext4: Add auto_da_alloc mount option

(cherry picked from commit afd4672dc7610b7feef5190168aa917cc2e417e4)

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>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>

diff --git a/fs/ext4/ext4.h b/fs/ext4/ext4.h
index 83f685da8bea82f908c31164b94b1de6d36a6fc9..a2bd86e30a87cc412d30dcf9679057c46f54e968 100644 (file)
--- a/fs/ext4/ext4.h
+++ b/fs/ext4/ext4.h
@@ -557,7 +557,7 @@ 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 9abf8c12c67ddb2a24583be9dc027a7b059c06c2..4fa4ee310d4bbe38a67a9b9343bc674519072a29 100644 (file)
--- a/fs/ext4/inode.c
+++ b/fs/ext4/inode.c
@@ -3887,7 +3887,7 @@ 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 63568ece154ddb68259031c6e675999f874276c9..8977e60bdcbb938fe48870754d6259e3cd13e20f 100644 (file)
--- a/fs/ext4/namei.c
+++ b/fs/ext4/namei.c
@@ -2457,7 +2457,8 @@ 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 39d1993cfa1370c3718dffd95231660f3dc606b4..1ad3c208cf95432b667c40b73ae36a12baec97be 100644 (file)
--- a/fs/ext4/super.c
+++ b/fs/ext4/super.c
@@ -803,8 +803,6 @@ 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));
@@ -855,6 +853,9 @@ 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;
 }
@@ -1002,7 +1003,7 @@ 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,
@@ -1037,8 +1038,6 @@ 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"},
@@ -1073,6 +1072,7 @@ 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},
 };
 
@@ -1205,12 +1205,6 @@ 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
@@ -1471,6 +1465,14 @@ 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\" "
@@ -2099,7 +2101,6 @@ 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);
 
        /*