> http://bugzilla.kernel.org/show_bug.cgi?id=15420 > > > Theodore Tso <tytso@xxxxxxx> changed: > > What |Removed |Added > ---------------------------------------------------------------------------- > CC| |tytso@xxxxxxx > > > > > --- Comment #5 from Theodore Tso <tytso@xxxxxxx> 2010-03-10 03:12:30 --- > This sounds like the block reservation code for delayed allocation is > over-aggressive about estimating how many blocks are need for the indirect > blocks in the case of indirect-mapped inodes (which would be what you get when > mounting an ext2 filesystem using the ext4 file system driver). > > This should be an aesthetic issue only, but it would be nice to have this be > fixed. Since bugzilla seems to be down now, I'll reply by email: Won't it make sence to use 'nodelalloc' by default when ext4 driver is used for ext2 or ext3 filesystem? Because delayed allocation has some implications people need not expect - like the overestimation of needed blocks, or changed semantics of ordered data mode etc... So something like the patch below? Honza -- Jan Kara <jack@xxxxxxx> SuSE CR Labs --- >From c5fa50757c0b81f661532b6f833946bd9294e439 Mon Sep 17 00:00:00 2001 From: Jan Kara <jack@xxxxxxx> Date: Wed, 10 Mar 2010 12:23:03 +0100 Subject: [PATCH] ext4: Don't use delayed allocation by default when used instead of ext[23] When ext4 driver is used to mount a filesystem instead of ext2 or ext3 driver, do not enable delayed allocation by default since it has some unobvious consequences (different semantics of data=ordered mode, overestimation of needed metadata blocks for allocation). Signed-off-by: Jan Kara <jack@xxxxxxx> --- fs/ext4/super.c | 20 +++++++++++--------- 1 files changed, 11 insertions(+), 9 deletions(-) diff --git a/fs/ext4/super.c b/fs/ext4/super.c index ce84a6e..7fc9ab3 100644 --- a/fs/ext4/super.c +++ b/fs/ext4/super.c @@ -68,7 +68,16 @@ static int ext4_statfs(struct dentry *dentry, struct kstatfs *buf); static int ext4_unfreeze(struct super_block *sb); static void ext4_write_super(struct super_block *sb); static int ext4_freeze(struct super_block *sb); +static int ext4_get_sb(struct file_system_type *fs_type, int flags, + const char *dev_name, void *data, struct vfsmount *mnt); +static struct file_system_type ext4_fs_type = { + .owner = THIS_MODULE, + .name = "ext4", + .get_sb = ext4_get_sb, + .kill_sb = kill_block_super, + .fs_flags = FS_REQUIRES_DEV, +}; ext4_fsblk_t ext4_block_bitmap(struct super_block *sb, struct ext4_group_desc *bg) @@ -2539,7 +2548,8 @@ static int ext4_fill_super(struct super_block *sb, void *data, int silent) * enable delayed allocation by default * Use -o nodelalloc to turn it off */ - set_opt(sbi->s_mount_opt, DELALLOC); + if (sb->s_bdev->bd_holder == &ext4_fs_type) + set_opt(sbi->s_mount_opt, DELALLOC); if (!parse_options((char *) data, sb, &journal_devnum, &journal_ioprio, NULL, 0)) @@ -4122,14 +4132,6 @@ static inline void register_as_ext3(void) { } static inline void unregister_as_ext3(void) { } #endif -static struct file_system_type ext4_fs_type = { - .owner = THIS_MODULE, - .name = "ext4", - .get_sb = ext4_get_sb, - .kill_sb = kill_block_super, - .fs_flags = FS_REQUIRES_DEV, -}; - static int __init init_ext4_fs(void) { int err; -- 1.6.4.2 -- To unsubscribe from this list: send the line "unsubscribe linux-ext4" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
