Messages in this thread | | | Date | Tue, 5 Jan 2010 01:47:42 +0100 | From | Jan Kara <> | Subject | Re: [PATCH 83/97] ext4: Fix potential quota deadlock |
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On Mon 04-01-10 16:33:36, Greg Kroah-Hartman wrote: > From: Dmitry Monakhov <dmonakhov@openvz.org> > > commit d21cd8f163ac44b15c465aab7306db931c606908 upstream. Ted has found a serious bug in this patch over Christmas and fixed it. Ted, do you prefer to just discard this patch or will you add your fixes?
Honza
> We have to delay vfs_dq_claim_space() until allocation context destruction. > Currently we have following call-trace: > ext4_mb_new_blocks() > /* task is already holding ac->alloc_semp */ > ->ext4_mb_mark_diskspace_used > ->vfs_dq_claim_space() /* acquire dqptr_sem here. Possible deadlock */ > ->ext4_mb_release_context() /* drop ac->alloc_semp here */ > > Let's move quota claiming to ext4_da_update_reserve_space() > > ======================================================= > [ INFO: possible circular locking dependency detected ] > 2.6.32-rc7 #18 > ------------------------------------------------------- > write-truncate-/3465 is trying to acquire lock: > (&s->s_dquot.dqptr_sem){++++..}, at: [<c025e73b>] dquot_claim_space+0x3b/0x1b0 > > but task is already holding lock: > (&meta_group_info[i]->alloc_sem){++++..}, at: [<c02ce962>] ext4_mb_load_buddy+0xb2/0x370 > > which lock already depends on the new lock. > > the existing dependency chain (in reverse order) is: > > -> #3 (&meta_group_info[i]->alloc_sem){++++..}: > [<c017d04b>] __lock_acquire+0xd7b/0x1260 > [<c017d5ea>] lock_acquire+0xba/0xd0 > [<c0527191>] down_read+0x51/0x90 > [<c02ce962>] ext4_mb_load_buddy+0xb2/0x370 > [<c02d0c1c>] ext4_mb_free_blocks+0x46c/0x870 > [<c029c9d3>] ext4_free_blocks+0x73/0x130 > [<c02c8cfc>] ext4_ext_truncate+0x76c/0x8d0 > [<c02a8087>] ext4_truncate+0x187/0x5e0 > [<c01e0f7b>] vmtruncate+0x6b/0x70 > [<c022ec02>] inode_setattr+0x62/0x190 > [<c02a2d7a>] ext4_setattr+0x25a/0x370 > [<c022ee81>] notify_change+0x151/0x340 > [<c021349d>] do_truncate+0x6d/0xa0 > [<c0221034>] may_open+0x1d4/0x200 > [<c022412b>] do_filp_open+0x1eb/0x910 > [<c021244d>] do_sys_open+0x6d/0x140 > [<c021258e>] sys_open+0x2e/0x40 > [<c0103100>] sysenter_do_call+0x12/0x32 > > -> #2 (&ei->i_data_sem){++++..}: > [<c017d04b>] __lock_acquire+0xd7b/0x1260 > [<c017d5ea>] lock_acquire+0xba/0xd0 > [<c0527191>] down_read+0x51/0x90 > [<c02a5787>] ext4_get_blocks+0x47/0x450 > [<c02a74c1>] ext4_getblk+0x61/0x1d0 > [<c02a7a7f>] ext4_bread+0x1f/0xa0 > [<c02bcddc>] ext4_quota_write+0x12c/0x310 > [<c0262d23>] qtree_write_dquot+0x93/0x120 > [<c0261708>] v2_write_dquot+0x28/0x30 > [<c025d3fb>] dquot_commit+0xab/0xf0 > [<c02be977>] ext4_write_dquot+0x77/0x90 > [<c02be9bf>] ext4_mark_dquot_dirty+0x2f/0x50 > [<c025e321>] dquot_alloc_inode+0x101/0x180 > [<c029fec2>] ext4_new_inode+0x602/0xf00 > [<c02ad789>] ext4_create+0x89/0x150 > [<c0221ff2>] vfs_create+0xa2/0xc0 > [<c02246e7>] do_filp_open+0x7a7/0x910 > [<c021244d>] do_sys_open+0x6d/0x140 > [<c021258e>] sys_open+0x2e/0x40 > [<c0103100>] sysenter_do_call+0x12/0x32 > > -> #1 (&sb->s_type->i_mutex_key#7/4){+.+...}: > [<c017d04b>] __lock_acquire+0xd7b/0x1260 > [<c017d5ea>] lock_acquire+0xba/0xd0 > [<c0526505>] mutex_lock_nested+0x65/0x2d0 > [<c0260c9d>] vfs_load_quota_inode+0x4bd/0x5a0 > [<c02610af>] vfs_quota_on_path+0x5f/0x70 > [<c02bc812>] ext4_quota_on+0x112/0x190 > [<c026345a>] sys_quotactl+0x44a/0x8a0 > [<c0103100>] sysenter_do_call+0x12/0x32 > > -> #0 (&s->s_dquot.dqptr_sem){++++..}: > [<c017d361>] __lock_acquire+0x1091/0x1260 > [<c017d5ea>] lock_acquire+0xba/0xd0 > [<c0527191>] down_read+0x51/0x90 > [<c025e73b>] dquot_claim_space+0x3b/0x1b0 > [<c02cb95f>] ext4_mb_mark_diskspace_used+0x36f/0x380 > [<c02d210a>] ext4_mb_new_blocks+0x34a/0x530 > [<c02c83fb>] ext4_ext_get_blocks+0x122b/0x13c0 > [<c02a5966>] ext4_get_blocks+0x226/0x450 > [<c02a5ff3>] mpage_da_map_blocks+0xc3/0xaa0 > [<c02a6ed6>] ext4_da_writepages+0x506/0x790 > [<c01de272>] do_writepages+0x22/0x50 > [<c01d766d>] __filemap_fdatawrite_range+0x6d/0x80 > [<c01d7b9b>] filemap_flush+0x2b/0x30 > [<c02a40ac>] ext4_alloc_da_blocks+0x5c/0x60 > [<c029e595>] ext4_release_file+0x75/0xb0 > [<c0216b59>] __fput+0xf9/0x210 > [<c0216c97>] fput+0x27/0x30 > [<c02122dc>] filp_close+0x4c/0x80 > [<c014510e>] put_files_struct+0x6e/0xd0 > [<c01451b7>] exit_files+0x47/0x60 > [<c0146a24>] do_exit+0x144/0x710 > [<c0147028>] do_group_exit+0x38/0xa0 > [<c0159abc>] get_signal_to_deliver+0x2ac/0x410 > [<c0102849>] do_notify_resume+0xb9/0x890 > [<c01032d2>] work_notifysig+0x13/0x21 > > other info that might help us debug this: > > 3 locks held by write-truncate-/3465: > #0: (jbd2_handle){+.+...}, at: [<c02e1f8f>] start_this_handle+0x38f/0x5c0 > #1: (&ei->i_data_sem){++++..}, at: [<c02a57f6>] ext4_get_blocks+0xb6/0x450 > #2: (&meta_group_info[i]->alloc_sem){++++..}, at: [<c02ce962>] ext4_mb_load_buddy+0xb2/0x370 > > stack backtrace: > Pid: 3465, comm: write-truncate- Not tainted 2.6.32-rc7 #18 > Call Trace: > [<c0524cb3>] ? printk+0x1d/0x22 > [<c017ac9a>] print_circular_bug+0xca/0xd0 > [<c017d361>] __lock_acquire+0x1091/0x1260 > [<c016bca2>] ? sched_clock_local+0xd2/0x170 > [<c0178fd0>] ? trace_hardirqs_off_caller+0x20/0xd0 > [<c017d5ea>] lock_acquire+0xba/0xd0 > [<c025e73b>] ? dquot_claim_space+0x3b/0x1b0 > [<c0527191>] down_read+0x51/0x90 > [<c025e73b>] ? dquot_claim_space+0x3b/0x1b0 > [<c025e73b>] dquot_claim_space+0x3b/0x1b0 > [<c02cb95f>] ext4_mb_mark_diskspace_used+0x36f/0x380 > [<c02d210a>] ext4_mb_new_blocks+0x34a/0x530 > [<c02c601d>] ? ext4_ext_find_extent+0x25d/0x280 > [<c02c83fb>] ext4_ext_get_blocks+0x122b/0x13c0 > [<c016bca2>] ? sched_clock_local+0xd2/0x170 > [<c016be60>] ? sched_clock_cpu+0x120/0x160 > [<c016beef>] ? cpu_clock+0x4f/0x60 > [<c0178fd0>] ? trace_hardirqs_off_caller+0x20/0xd0 > [<c052712c>] ? down_write+0x8c/0xa0 > [<c02a5966>] ext4_get_blocks+0x226/0x450 > [<c016be60>] ? sched_clock_cpu+0x120/0x160 > [<c016beef>] ? cpu_clock+0x4f/0x60 > [<c017908b>] ? trace_hardirqs_off+0xb/0x10 > [<c02a5ff3>] mpage_da_map_blocks+0xc3/0xaa0 > [<c01d69cc>] ? find_get_pages_tag+0x16c/0x180 > [<c01d6860>] ? find_get_pages_tag+0x0/0x180 > [<c02a73bd>] ? __mpage_da_writepage+0x16d/0x1a0 > [<c01dfc4e>] ? pagevec_lookup_tag+0x2e/0x40 > [<c01ddf1b>] ? write_cache_pages+0xdb/0x3d0 > [<c02a7250>] ? __mpage_da_writepage+0x0/0x1a0 > [<c02a6ed6>] ext4_da_writepages+0x506/0x790 > [<c016beef>] ? cpu_clock+0x4f/0x60 > [<c016bca2>] ? sched_clock_local+0xd2/0x170 > [<c016be60>] ? sched_clock_cpu+0x120/0x160 > [<c016be60>] ? sched_clock_cpu+0x120/0x160 > [<c02a69d0>] ? ext4_da_writepages+0x0/0x790 > [<c01de272>] do_writepages+0x22/0x50 > [<c01d766d>] __filemap_fdatawrite_range+0x6d/0x80 > [<c01d7b9b>] filemap_flush+0x2b/0x30 > [<c02a40ac>] ext4_alloc_da_blocks+0x5c/0x60 > [<c029e595>] ext4_release_file+0x75/0xb0 > [<c0216b59>] __fput+0xf9/0x210 > [<c0216c97>] fput+0x27/0x30 > [<c02122dc>] filp_close+0x4c/0x80 > [<c014510e>] put_files_struct+0x6e/0xd0 > [<c01451b7>] exit_files+0x47/0x60 > [<c0146a24>] do_exit+0x144/0x710 > [<c017b163>] ? lock_release_holdtime+0x33/0x210 > [<c0528137>] ? _spin_unlock_irq+0x27/0x30 > [<c0147028>] do_group_exit+0x38/0xa0 > [<c017babb>] ? trace_hardirqs_on+0xb/0x10 > [<c0159abc>] get_signal_to_deliver+0x2ac/0x410 > [<c0102849>] do_notify_resume+0xb9/0x890 > [<c0178fd0>] ? trace_hardirqs_off_caller+0x20/0xd0 > [<c017b163>] ? lock_release_holdtime+0x33/0x210 > [<c0165b50>] ? autoremove_wake_function+0x0/0x50 > [<c017ba54>] ? trace_hardirqs_on_caller+0x134/0x190 > [<c017babb>] ? trace_hardirqs_on+0xb/0x10 > [<c0300ba4>] ? security_file_permission+0x14/0x20 > [<c0215761>] ? vfs_write+0x131/0x190 > [<c0214f50>] ? do_sync_write+0x0/0x120 > [<c0103115>] ? sysenter_do_call+0x27/0x32 > [<c01032d2>] work_notifysig+0x13/0x21 > > CC: Theodore Ts'o <tytso@mit.edu> > Signed-off-by: Dmitry Monakhov <dmonakhov@openvz.org> > Signed-off-by: Jan Kara <jack@suse.cz> > Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de> > --- > fs/ext4/inode.c | 9 +++++++-- > fs/ext4/mballoc.c | 6 ------ > 2 files changed, 7 insertions(+), 8 deletions(-) > > diff --git a/fs/ext4/inode.c b/fs/ext4/inode.c > index 374d38c..9fc624d 100644 > --- a/fs/ext4/inode.c > +++ b/fs/ext4/inode.c > @@ -1088,7 +1088,7 @@ static int ext4_calc_metadata_amount(struct inode *inode, int blocks) > static void ext4_da_update_reserve_space(struct inode *inode, int used) > { > struct ext4_sb_info *sbi = EXT4_SB(inode->i_sb); > - int total, mdb, mdb_free; > + int total, mdb, mdb_free, mdb_claim = 0; > > spin_lock(&EXT4_I(inode)->i_block_reservation_lock); > /* recalculate the number of metablocks still need to be reserved */ > @@ -1101,7 +1101,9 @@ static void ext4_da_update_reserve_space(struct inode *inode, int used) > > if (mdb_free) { > /* Account for allocated meta_blocks */ > - mdb_free -= EXT4_I(inode)->i_allocated_meta_blocks; > + mdb_claim = EXT4_I(inode)->i_allocated_meta_blocks; > + BUG_ON(mdb_free < mdb_claim); > + mdb_free -= mdb_claim; > > /* update fs dirty blocks counter */ > percpu_counter_sub(&sbi->s_dirtyblocks_counter, mdb_free); > @@ -1112,8 +1114,11 @@ static void ext4_da_update_reserve_space(struct inode *inode, int used) > /* update per-inode reservations */ > BUG_ON(used > EXT4_I(inode)->i_reserved_data_blocks); > EXT4_I(inode)->i_reserved_data_blocks -= used; > + percpu_counter_sub(&sbi->s_dirtyblocks_counter, used + mdb_claim); > spin_unlock(&EXT4_I(inode)->i_block_reservation_lock); > > + vfs_dq_claim_block(inode, used + mdb_claim); > + > /* > * free those over-booking quota for metadata blocks > */ > diff --git a/fs/ext4/mballoc.c b/fs/ext4/mballoc.c > index 7d71148..82b9778 100644 > --- a/fs/ext4/mballoc.c > +++ b/fs/ext4/mballoc.c > @@ -2755,12 +2755,6 @@ ext4_mb_mark_diskspace_used(struct ext4_allocation_context *ac, > if (!(ac->ac_flags & EXT4_MB_DELALLOC_RESERVED)) > /* release all the reserved blocks if non delalloc */ > percpu_counter_sub(&sbi->s_dirtyblocks_counter, reserv_blks); > - else { > - percpu_counter_sub(&sbi->s_dirtyblocks_counter, > - ac->ac_b_ex.fe_len); > - /* convert reserved quota blocks to real quota blocks */ > - vfs_dq_claim_block(ac->ac_inode, ac->ac_b_ex.fe_len); > - } > > if (sbi->s_log_groups_per_flex) { > ext4_group_t flex_group = ext4_flex_group(sbi, > -- > 1.6.6 > -- Jan Kara <jack@suse.cz> SUSE Labs, CR
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