4 files changed, 58 insertions, 49 deletions

diff --git a/fs/ext3/Kconfig b/fs/ext3/Kconfig
index fb3c1a21b135..522b15498f45 100644
--- a/fs/ext3/Kconfig
+++ b/fs/ext3/Kconfig
@@ -29,23 +29,25 @@ config EXT3_FS
           module will be called ext3.
 
 config EXT3_DEFAULTS_TO_ORDERED
-        bool "Default to 'data=ordered' in ext3 (legacy option)"
+        bool "Default to 'data=ordered' in ext3"
         depends on EXT3_FS
         help
-          If a filesystem does not explicitly specify a data ordering
-          mode, and the journal capability allowed it, ext3 used to
-          historically default to 'data=ordered'.
-
-          That was a rather unfortunate choice, because it leads to all
-          kinds of latency problems, and the 'data=writeback' mode is more
-          appropriate these days.
-
-          You should probably always answer 'n' here, and if you really
-          want to use 'data=ordered' mode, set it in the filesystem itself
-          with 'tune2fs -o journal_data_ordered'.
-
-          But if you really want to enable the legacy default, you can do
-          so by answering 'y' to this question.
+          The journal mode options for ext3 have different tradeoffs
+          between when data is guaranteed to be on disk and
+          performance.  The use of "data=writeback" can cause
+          unwritten data to appear in files after an system crash or
+          power failure, which can be a security issue.  However,
+          "data=ordered" mode can also result in major performance
+          problems, including seconds-long delays before an fsync()
+          call returns.  For details, see:
+
+          http://ext4.wiki.kernel.org/index.php/Ext3_data_mode_tradeoffs
+
+          If you have been historically happy with ext3's performance,
+          data=ordered mode will be a safe choice and you should
+          answer 'y' here.  If you understand the reliability and data
+          privacy issues of data=writeback and are willing to make
+          that trade off, answer 'n'.
 
 config EXT3_FS_XATTR
         bool "Ext3 extended attributes"
diff --git a/fs/ext3/dir.c b/fs/ext3/dir.c
index 3d724a95882f..373fa90c796a 100644
--- a/fs/ext3/dir.c
+++ b/fs/ext3/dir.c
@@ -130,8 +130,7 @@ static int ext3_readdir(struct file * filp,
                 struct buffer_head *bh = NULL;
 
                 map_bh.b_state = 0;
-                err = ext3_get_blocks_handle(NULL, inode, blk, 1,
-                                                &map_bh, 0, 0);
+                err = ext3_get_blocks_handle(NULL, inode, blk, 1, &map_bh, 0);
                 if (err > 0) {
                         pgoff_t index = map_bh.b_blocknr >>
                                         (PAGE_CACHE_SHIFT - inode->i_blkbits);
diff --git a/fs/ext3/inode.c b/fs/ext3/inode.c
index 5f51fed5c750..b49908a167ae 100644
--- a/fs/ext3/inode.c
+++ b/fs/ext3/inode.c
@@ -788,7 +788,7 @@ err_out:
 int ext3_get_blocks_handle(handle_t *handle, struct inode *inode,
                 sector_t iblock, unsigned long maxblocks,
                 struct buffer_head *bh_result,
-                int create, int extend_disksize)
+                int create)
 {
         int err = -EIO;
         int offsets[4];
@@ -911,13 +911,6 @@ int ext3_get_blocks_handle(handle_t *handle, struct inode *inode,
         if (!err)
                 err = ext3_splice_branch(handle, inode, iblock,
                                         partial, indirect_blks, count);
-        /*
-         * i_disksize growing is protected by truncate_mutex.  Don't forget to
-         * protect it if you're about to implement concurrent
-         * ext3_get_block() -bzzz
-        */
-        if (!err && extend_disksize && inode->i_size > ei->i_disksize)
-                ei->i_disksize = inode->i_size;
         mutex_unlock(&ei->truncate_mutex);
         if (err)
                 goto cleanup;
@@ -972,7 +965,7 @@ static int ext3_get_block(struct inode *inode, sector_t iblock,
         }
 
         ret = ext3_get_blocks_handle(handle, inode, iblock,
-                                        max_blocks, bh_result, create, 0);
+                                        max_blocks, bh_result, create);
         if (ret > 0) {
                 bh_result->b_size = (ret << inode->i_blkbits);
                 ret = 0;
@@ -1005,7 +998,7 @@ struct buffer_head *ext3_getblk(handle_t *handle, struct inode *inode,
         dummy.b_blocknr = -1000;
         buffer_trace_init(&dummy.b_history);
         err = ext3_get_blocks_handle(handle, inode, block, 1,
-                                        &dummy, create, 1);
+                                        &dummy, create);
         /*
          * ext3_get_blocks_handle() returns number of blocks
          * mapped. 0 in case of a HOLE.
@@ -1193,15 +1186,16 @@ write_begin_failed:
                  * i_size_read because we hold i_mutex.
                  *
                  * Add inode to orphan list in case we crash before truncate
-                 * finishes.
+                 * finishes. Do this only if ext3_can_truncate() agrees so
+                 * that orphan processing code is happy.
                  */
-                if (pos + len > inode->i_size)
+                if (pos + len > inode->i_size && ext3_can_truncate(inode))
                         ext3_orphan_add(handle, inode);
                 ext3_journal_stop(handle);
                 unlock_page(page);
                 page_cache_release(page);
                 if (pos + len > inode->i_size)
-                        vmtruncate(inode, inode->i_size);
+                        ext3_truncate(inode);
         }
         if (ret == -ENOSPC && ext3_should_retry_alloc(inode->i_sb, &retries))
                 goto retry;
@@ -1287,7 +1281,7 @@ static int ext3_ordered_write_end(struct file *file,
          * There may be allocated blocks outside of i_size because
          * we failed to copy some data. Prepare for truncate.
          */
-        if (pos + len > inode->i_size)
+        if (pos + len > inode->i_size && ext3_can_truncate(inode))
                 ext3_orphan_add(handle, inode);
         ret2 = ext3_journal_stop(handle);
         if (!ret)
@@ -1296,7 +1290,7 @@ static int ext3_ordered_write_end(struct file *file,
         page_cache_release(page);
 
         if (pos + len > inode->i_size)
-                vmtruncate(inode, inode->i_size);
+                ext3_truncate(inode);
         return ret ? ret : copied;
 }
 
@@ -1315,14 +1309,14 @@ static int ext3_writeback_write_end(struct file *file,
          * There may be allocated blocks outside of i_size because
          * we failed to copy some data. Prepare for truncate.
          */
-        if (pos + len > inode->i_size)
+        if (pos + len > inode->i_size && ext3_can_truncate(inode))
                 ext3_orphan_add(handle, inode);
         ret = ext3_journal_stop(handle);
         unlock_page(page);
         page_cache_release(page);
 
         if (pos + len > inode->i_size)
-                vmtruncate(inode, inode->i_size);
+                ext3_truncate(inode);
         return ret ? ret : copied;
 }
 
@@ -1358,7 +1352,7 @@ static int ext3_journalled_write_end(struct file *file,
          * There may be allocated blocks outside of i_size because
          * we failed to copy some data. Prepare for truncate.
          */
-        if (pos + len > inode->i_size)
+        if (pos + len > inode->i_size && ext3_can_truncate(inode))
                 ext3_orphan_add(handle, inode);
         EXT3_I(inode)->i_state |= EXT3_STATE_JDATA;
         if (inode->i_size > EXT3_I(inode)->i_disksize) {
@@ -1375,7 +1369,7 @@ static int ext3_journalled_write_end(struct file *file,
         page_cache_release(page);
 
         if (pos + len > inode->i_size)
-                vmtruncate(inode, inode->i_size);
+                ext3_truncate(inode);
         return ret ? ret : copied;
 }
 
diff --git a/fs/ext3/super.c b/fs/ext3/super.c
index 524b349c6299..a8d80a7f1105 100644
--- a/fs/ext3/super.c
+++ b/fs/ext3/super.c
@@ -543,6 +543,19 @@ static inline void ext3_show_quota_options(struct seq_file *seq, struct super_bl
 #endif
 }
 
+static char *data_mode_string(unsigned long mode)
+{
+        switch (mode) {
+        case EXT3_MOUNT_JOURNAL_DATA:
+                return "journal";
+        case EXT3_MOUNT_ORDERED_DATA:
+                return "ordered";
+        case EXT3_MOUNT_WRITEBACK_DATA:
+                return "writeback";
+        }
+        return "unknown";
+}
+
 /*
  * Show an option if
  *  - it's set to a non-default value OR
@@ -616,13 +629,8 @@ static int ext3_show_options(struct seq_file *seq, struct vfsmount *vfs)
         if (test_opt(sb, NOBH))
                 seq_puts(seq, ",nobh");
 
-        if (test_opt(sb, DATA_FLAGS) == EXT3_MOUNT_JOURNAL_DATA)
-                seq_puts(seq, ",data=journal");
-        else if (test_opt(sb, DATA_FLAGS) == EXT3_MOUNT_ORDERED_DATA)
-                seq_puts(seq, ",data=ordered");
-        else if (test_opt(sb, DATA_FLAGS) == EXT3_MOUNT_WRITEBACK_DATA)
-                seq_puts(seq, ",data=writeback");
-
+        seq_printf(seq, ",data=%s", data_mode_string(sbi->s_mount_opt &
+                                                     EXT3_MOUNT_DATA_FLAGS));
         if (test_opt(sb, DATA_ERR_ABORT))
                 seq_puts(seq, ",data_err=abort");
 
@@ -1024,12 +1032,18 @@ static int parse_options (char *options, struct super_block *sb,
                 datacheck:
                         if (is_remount) {
                                 if ((sbi->s_mount_opt & EXT3_MOUNT_DATA_FLAGS)
-                                                != data_opt) {
-                                        printk(KERN_ERR
-                                                "EXT3-fs: cannot change data "
-                                                "mode on remount\n");
-                                        return 0;
-                                }
+                                                == data_opt)
+                                        break;
+                                printk(KERN_ERR
+                                        "EXT3-fs (device %s): Cannot change "
+                                        "data mode on remount. The filesystem "
+                                        "is mounted in data=%s mode and you "
+                                        "try to remount it in data=%s mode.\n",
+                                        sb->s_id,
+                                        data_mode_string(sbi->s_mount_opt &
+                                                        EXT3_MOUNT_DATA_FLAGS),
+                                        data_mode_string(data_opt));
+                                return 0;
                         } else {
                                 sbi->s_mount_opt &= ~EXT3_MOUNT_DATA_FLAGS;
                                 sbi->s_mount_opt |= data_opt;