I would like to spend some time to see whether we can add sb_issue_discard() somewhere else for non-journaled mode. It is a useful feature to be included for both modes. Jiaying On Tue, Nov 9, 2010 at 8:36 AM, Eric Sandeen <sandeen@xxxxxxxxxx> wrote: > > On 11/8/10 12:06 AM, Theodore Ts'o wrote: > > Commit 5c521830cf (ext4: Support discard requests when running in > > no-journal mode) attempts to add sb_issue_discard() for data blocks > > (in data=writeback mode) and in no-journal mode. Unfortunately, this > > no longer works, because in commit dd3932eddf (block: remove > > BLKDEV_IFL_WAIT), sb_issue_discard() only presents a synchronous > > interface, and there are times when we call ext4_free_blocks() when we > > are are holding a spinlock, or are otherwise in an atomic context. > > > > For now, I've removed the call to sb_issue_discard() to prevent a > > deadlock or (if spinlock debugging is enabled) failures like this: > > perhaps mount should fail with the combination of -o discard and no > journal present? > > -Eric > > > BUG: scheduling while atomic: rc.sysinit/1376/0x00000002 > > Pid: 1376, comm: rc.sysinit Not tainted 2.6.36-ARCH #1 > > Call Trace: > > [<ffffffff810397ce>] __schedule_bug+0x5e/0x70 > > [<ffffffff81403110>] schedule+0x950/0xa70 > > [<ffffffff81060bad>] ? insert_work+0x7d/0x90 > > [<ffffffff81060fbd>] ? queue_work_on+0x1d/0x30 > > [<ffffffff81061127>] ? queue_work+0x37/0x60 > > [<ffffffff8140377d>] schedule_timeout+0x21d/0x360 > > [<ffffffff812031c3>] ? generic_make_request+0x2c3/0x540 > > [<ffffffff81402680>] wait_for_common+0xc0/0x150 > > [<ffffffff81041490>] ? default_wake_function+0x0/0x10 > > [<ffffffff812034bc>] ? submit_bio+0x7c/0x100 > > [<ffffffff810680a0>] ? wake_bit_function+0x0/0x40 > > [<ffffffff814027b8>] wait_for_completion+0x18/0x20 > > [<ffffffff8120a969>] blkdev_issue_discard+0x1b9/0x210 > > [<ffffffff811ba03e>] ext4_free_blocks+0x68e/0xb60 > > [<ffffffff811b1650>] ? __ext4_handle_dirty_metadata+0x110/0x120 > > [<ffffffff811b098c>] ext4_ext_truncate+0x8cc/0xa70 > > [<ffffffff810d713e>] ? pagevec_lookup+0x1e/0x30 > > [<ffffffff81191618>] ext4_truncate+0x178/0x5d0 > > [<ffffffff810eacbb>] ? unmap_mapping_range+0xab/0x280 > > [<ffffffff810d8976>] vmtruncate+0x56/0x70 > > [<ffffffff811925cb>] ext4_setattr+0x14b/0x460 > > [<ffffffff811319e4>] notify_change+0x194/0x380 > > [<ffffffff81117f80>] do_truncate+0x60/0x90 > > [<ffffffff811e08fa>] ? security_inode_permission+0x1a/0x20 > > [<ffffffff811eaec1>] ? tomoyo_path_truncate+0x11/0x20 > > [<ffffffff81127539>] do_last+0x5d9/0x770 > > [<ffffffff811278bd>] do_filp_open+0x1ed/0x680 > > [<ffffffff8140644f>] ? page_fault+0x1f/0x30 > > [<ffffffff81132bfc>] ? alloc_fd+0xec/0x140 > > [<ffffffff81118db1>] do_sys_open+0x61/0x120 > > [<ffffffff81118e8b>] sys_open+0x1b/0x20 > > [<ffffffff81002e6b>] system_call_fastpath+0x16/0x1b > > > > https://bugzilla.kernel.org/show_bug.cgi?id=22302 > > > > Reported-by: Mathias Burén <mathias.buren@xxxxxxxxx> > > Signed-off-by: "Theodore Ts'o" <tytso@xxxxxxx> > > Cc: jiayingz@xxxxxxxxxx > > --- > > fs/ext4/mballoc.c | 2 -- > > 1 files changed, 0 insertions(+), 2 deletions(-) > > > > diff --git a/fs/ext4/mballoc.c b/fs/ext4/mballoc.c > > index c58eba3..5b4d4e3 100644 > > --- a/fs/ext4/mballoc.c > > +++ b/fs/ext4/mballoc.c > > @@ -4640,8 +4640,6 @@ do_more: > > * with group lock held. generate_buddy look at > > * them with group lock_held > > */ > > - if (test_opt(sb, DISCARD)) > > - ext4_issue_discard(sb, block_group, bit, count); > > ext4_lock_group(sb, block_group); > > mb_clear_bits(bitmap_bh->b_data, bit, count); > > mb_free_blocks(inode, &e4b, bit, count); > -- 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
