diff options
| -rw-r--r-- | fs/ext3/Kconfig | 32 | ||||
| -rw-r--r-- | fs/ext3/super.c | 40 |
2 files changed, 44 insertions, 28 deletions
diff --git a/fs/ext3/Kconfig b/fs/ext3/Kconfig index fb3c1a2..522b154 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/super.c b/fs/ext3/super.c index 524b349..a8d80a7 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; |
