Messages in this thread Patch in this message | | | Date | Mon, 07 Dec 2009 11:28:38 +0900 | From | Hiroshi Shimamoto <> | Subject | Re: + task_struct-make-journal_info-conditional.patch added to -mm tree |
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Alexey Dobriyan wrote: > On Fri, Dec 04, 2009 at 12:58:06PM +0900, Hiroshi Shimamoto wrote: >> Alexey Dobriyan wrote: >>> On Thu, Dec 03, 2009 at 02:40:57PM -0800, akpm@linux-foundation.org wrote: >>>> --- a/include/linux/sched.h~task_struct-make-journal_info-conditional >>>> +++ a/include/linux/sched.h >>>> @@ -1452,8 +1452,10 @@ struct task_struct { >>>> gfp_t lockdep_reclaim_gfp; >>>> #endif >>>> >>>> +#ifdef CONFIG_FS_JOURNAL_INFO >>>> /* journalling filesystem info */ >>>> void *journal_info; >>>> +#endif >>> This will prevent using e.g. ext3 on CONFIG_EXT3_FS=n kernels. >> I'm sorry, I'm not sure what you're mentioning. > > With this patch admin must decide in advance if he will ever use ext3. > EXT3_FS=n kernels won't be able to get ext3 support without reboot > even as module, because task_struct will be different.
I see, you want to keep this field for future use even if EXT3_FS=n. I think, however, there might be a need to remove this because the user never enable any journaling filesystem.
> > Which is a regression compared to current state.
I understand it's a regression, so how about make this option Y by default?
==== From: Hiroshi Shimamoto <h-shimamoto@ct.jp.nec.com> Subject: [PATCH v2] task_struct: make journal_info conditional
journal_info in task_struct is used in journaling file system only. So introduce CONFIG_FS_JOURNAL_INFO and make it conditional.
Signed-off-by: Hiroshi Shimamoto <h-shimamoto@ct.jp.nec.com> CC: Chris Mason <chris.mason@oracle.com> CC: "Theodore Ts'o" <tytso@mit.edu> CC: Steven Whitehouse <swhiteho@redhat.com> CC: KONISHI Ryusuke <konishi.ryusuke@lab.ntt.co.jp> CC: Andrew Morton <akpm@linux-foundation.org> --- v1->v2: Make FS_JOURNAL_INFO Y by default, and add help document.
fs/Kconfig | 12 ++++++++++++ fs/btrfs/Kconfig | 1 + fs/ext4/Kconfig | 1 + fs/gfs2/Kconfig | 1 + fs/jbd/Kconfig | 1 + fs/jbd2/Kconfig | 1 + fs/nilfs2/Kconfig | 1 + fs/reiserfs/Kconfig | 1 + include/linux/init_task.h | 8 +++++++- include/linux/sched.h | 2 ++ 10 files changed, 28 insertions(+), 1 deletions(-)
diff --git a/fs/Kconfig b/fs/Kconfig index 2aa5663..a684c1b 100644 --- a/fs/Kconfig +++ b/fs/Kconfig @@ -6,6 +6,18 @@ menu "File systems" if BLOCK +config FS_JOURNAL_INFO + bool "Include FS Journal Info in task struct" + default y + help + Include Journal Information in task struct for journaling filesystem. + It used in Btrfs, EXT3, EXT4, GFS2, NILFS2 and Reiserfs. + If you say N, remove the field for journal info from task struct, it + reduces task struct size but disables to support the above journaling + filesystems. + + Say Y if unsure. + source "fs/ext2/Kconfig" source "fs/ext3/Kconfig" source "fs/ext4/Kconfig" diff --git a/fs/btrfs/Kconfig b/fs/btrfs/Kconfig index 7bb3c02..402afe0 100644 --- a/fs/btrfs/Kconfig +++ b/fs/btrfs/Kconfig @@ -4,6 +4,7 @@ config BTRFS_FS select LIBCRC32C select ZLIB_INFLATE select ZLIB_DEFLATE + select FS_JOURNAL_INFO help Btrfs is a new filesystem with extents, writable snapshotting, support for multiple devices and many more features. diff --git a/fs/ext4/Kconfig b/fs/ext4/Kconfig index 9f2d45d..464b486 100644 --- a/fs/ext4/Kconfig +++ b/fs/ext4/Kconfig @@ -2,6 +2,7 @@ config EXT4_FS tristate "The Extended 4 (ext4) filesystem" select JBD2 select CRC16 + select FS_JOURNAL_INFO help This is the next generation of the ext3 filesystem. diff --git a/fs/gfs2/Kconfig b/fs/gfs2/Kconfig index 4dcddf8..b192c66 100644 --- a/fs/gfs2/Kconfig +++ b/fs/gfs2/Kconfig @@ -10,6 +10,7 @@ config GFS2_FS select SLOW_WORK select QUOTA select QUOTACTL + select FS_JOURNAL_INFO help A cluster filesystem. diff --git a/fs/jbd/Kconfig b/fs/jbd/Kconfig index 4e28bee..a840898 100644 --- a/fs/jbd/Kconfig +++ b/fs/jbd/Kconfig @@ -1,5 +1,6 @@ config JBD tristate + select FS_JOURNAL_INFO help This is a generic journalling layer for block devices. It is currently used by the ext3 file system, but it could also be diff --git a/fs/jbd2/Kconfig b/fs/jbd2/Kconfig index f32f346..0f7d1ce 100644 --- a/fs/jbd2/Kconfig +++ b/fs/jbd2/Kconfig @@ -1,6 +1,7 @@ config JBD2 tristate select CRC32 + select FS_JOURNAL_INFO help This is a generic journaling layer for block devices that support both 32-bit and 64-bit block numbers. It is currently used by diff --git a/fs/nilfs2/Kconfig b/fs/nilfs2/Kconfig index 251da07..1225af7 100644 --- a/fs/nilfs2/Kconfig +++ b/fs/nilfs2/Kconfig @@ -2,6 +2,7 @@ config NILFS2_FS tristate "NILFS2 file system support (EXPERIMENTAL)" depends on EXPERIMENTAL select CRC32 + select FS_JOURNAL_INFO help NILFS2 is a log-structured file system (LFS) supporting continuous snapshotting. In addition to versioning capability of the entire diff --git a/fs/reiserfs/Kconfig b/fs/reiserfs/Kconfig index 513f431..ac7cd75 100644 --- a/fs/reiserfs/Kconfig +++ b/fs/reiserfs/Kconfig @@ -1,6 +1,7 @@ config REISERFS_FS tristate "Reiserfs support" select CRC32 + select FS_JOURNAL_INFO help Stores not just filenames but the files themselves in a balanced tree. Uses journalling. diff --git a/include/linux/init_task.h b/include/linux/init_task.h index 8d10aa7..8ed0abf 100644 --- a/include/linux/init_task.h +++ b/include/linux/init_task.h @@ -111,6 +111,12 @@ extern struct cred init_cred; # define INIT_PERF_EVENTS(tsk) #endif +#ifdef CONFIG_FS_JOURNAL_INFO +#define INIT_JOURNAL_INFO .journal_info = NULL, +#else +#define INIT_JOURNAL_INFO +#endif + /* * INIT_TASK is used to set up the first task table, touch at * your own risk!. Base=0, limit=0x1fffff (=2MB) @@ -162,7 +168,6 @@ extern struct cred init_cred; .signal = {{0}}}, \ .blocked = {{0}}, \ .alloc_lock = __SPIN_LOCK_UNLOCKED(tsk.alloc_lock), \ - .journal_info = NULL, \ .cpu_timers = INIT_CPU_TIMERS(tsk.cpu_timers), \ .fs_excl = ATOMIC_INIT(0), \ .pi_lock = __SPIN_LOCK_UNLOCKED(tsk.pi_lock), \ @@ -173,6 +178,7 @@ extern struct cred init_cred; [PIDTYPE_SID] = INIT_PID_LINK(PIDTYPE_SID), \ }, \ .dirties = INIT_PROP_LOCAL_SINGLE(dirties), \ + INIT_JOURNAL_INFO \ INIT_IDS \ INIT_PERF_EVENTS(tsk) \ INIT_TRACE_IRQFLAGS \ diff --git a/include/linux/sched.h b/include/linux/sched.h index c13c43e..92b1325 100644 --- a/include/linux/sched.h +++ b/include/linux/sched.h @@ -1452,8 +1452,10 @@ struct task_struct { gfp_t lockdep_reclaim_gfp; #endif +#ifdef CONFIG_FS_JOURNAL_INFO /* journalling filesystem info */ void *journal_info; +#endif /* stacked block device info */ struct bio *bio_list, **bio_tail; -- 1.6.5.5
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