[PATCH 1/5] bcache: Add a cond_resched() call to gc
From: Kent Overstreet
Date: Sat Nov 01 2014 - 16:44:47 EST
Change-id: Id4f18c533b80ddb40df94ed0bb5e2a236a4bc325
Signed-off-by: Takashi Iwai <tiwai@xxxxxxx>
---
drivers/md/bcache/btree.c | 1 +
1 file changed, 1 insertion(+)
--- a/drivers/md/bcache/btree.c
+++ b/drivers/md/bcache/btree.c
@@ -1741,6 +1741,7 @@ static void bch_btree_gc(struct cache_se
do {
ret = btree_root(gc_root, c, &op, &writes, &stats);
closure_sync(&writes);
+ cond_resched();
if (ret && ret != -EAGAIN)
pr_warn("gc failed!");
From: Joshua Schmid <jschmid@xxxxxxxx>
Subject: [PATCH] bcache: [BUG] clear BCACHE_DEV_UNLINK_DONE flag when
attaching a backing device
Newsgroups: gmane.linux.kernel.bcache.devel
Date: 2015-02-03 11:18:01 GMT (3 weeks, 2 days, 11 hours and 45 minutes ago)
From: Zheng Liu <wenqing.lz@xxxxxxxxxx>
This bug can be reproduced by the following script:
#!/bin/bash
bcache_sysfs="/sys/fs/bcache"
function clear_cache()
{
if [ ! -e $bcache_sysfs ]; then
echo "no bcache sysfs"
exit
fi
cset_uuid=$(ls -l $bcache_sysfs|head -n 2|tail -n 1|awk '{print $9}')
sudo sh -c "echo $cset_uuid > /sys/block/sdb/sdb1/bcache/detach"
sleep 5
sudo sh -c "echo $cset_uuid > /sys/block/sdb/sdb1/bcache/attach"
}
for ((i=0;i<10;i++)); do
clear_cache
done
The warning messages look like below:
[ 275.948611] ------------[ cut here ]------------
[ 275.963840] WARNING: at fs/sysfs/dir.c:512
sysfs_add_one+0xb8/0xd0() (Tainted: P W
--------------- )
[ 275.979253] Hardware name: Tecal RH2285
[ 275.994106] sysfs: cannot create duplicate filename
'/devices/pci0000:00/0000:00:09.0/0000:08:00.0/host4/target4:2:1/4:2:1:0/block/sdb/sdb1/bcache/cache'
[ 276.024105] Modules linked in: bcache tcp_diag inet_diag
ipmi_devintf ipmi_si ipmi_msghandler
bonding 8021q garp stp llc ipv6 ext3 jbd loop sg iomemory_vsl(P) bnx2
microcode serio_raw i2c_i801
i2c_core iTCO_wdt iTCO_vendor_support i7core_edac edac_core shpchp
ext4 jbd2 mbcache megaraid_sas
pata_acpi ata_generic ata_piix dm_mod [last unloaded: scsi_wait_scan]
[ 276.072643] Pid: 2765, comm: sh Tainted: P W
--------------- 2.6.32 #1
[ 276.089315] Call Trace:
[ 276.105801] [<ffffffff81070fe7>] ? warn_slowpath_common+0x87/0xc0
[ 276.122650] [<ffffffff810710d6>] ? warn_slowpath_fmt+0x46/0x50
[ 276.139361] [<ffffffff81205c08>] ? sysfs_add_one+0xb8/0xd0
[ 276.156012] [<ffffffff8120609b>] ? sysfs_do_create_link+0x12b/0x170
[ 276.172682] [<ffffffff81206113>] ? sysfs_create_link+0x13/0x20
[ 276.189282] [<ffffffffa03bda21>] ? bcache_device_link+0xc1/0x110 [bcache]
[ 276.205993] [<ffffffffa03bfa08>] ?
bch_cached_dev_attach+0x478/0x4f0 [bcache]
[ 276.222794] [<ffffffffa03c4a17>] ? bch_cached_dev_store+0x627/0x780 [bcache]
[ 276.239680] [<ffffffff8116783a>] ? alloc_pages_current+0xaa/0x110
[ 276.256594] [<ffffffff81203b15>] ? sysfs_write_file+0xe5/0x170
[ 276.273364] [<ffffffff811887b8>] ? vfs_write+0xb8/0x1a0
[ 276.290133] [<ffffffff811890b1>] ? sys_write+0x51/0x90
[ 276.306368] [<ffffffff8100c072>] ? system_call_fastpath+0x16/0x1b
[ 276.322301] ---[ end trace 9f5d4fcdd0c3edfb ]---
[ 276.338241] ------------[ cut here ]------------
[ 276.354109] WARNING: at /home/wenqing.lz/bcache/bcache/super.c:720
bcache_device_link+0xdf/0x110 [bcache]() (Tainted: P W
--------------- )
[ 276.386017] Hardware name: Tecal RH2285
[ 276.401430] Couldn't create device <-> cache set symlinks
[ 276.401759] Modules linked in: bcache tcp_diag inet_diag
ipmi_devintf ipmi_si ipmi_msghandler
bonding 8021q garp stp llc ipv6 ext3 jbd loop sg iomemory_vsl(P) bnx2
microcode serio_raw i2c_i801
i2c_core iTCO_wdt iTCO_vendor_support i7core_edac edac_core shpchp
ext4 jbd2 mbcache megaraid_sas
pata_acpi ata_generic ata_piix dm_mod [last unloaded: scsi_wait_scan]
[ 276.465477] Pid: 2765, comm: sh Tainted: P W
--------------- 2.6.32 #1
[ 276.482169] Call Trace:
[ 276.498610] [<ffffffff81070fe7>] ? warn_slowpath_common+0x87/0xc0
[ 276.515405] [<ffffffff810710d6>] ? warn_slowpath_fmt+0x46/0x50
[ 276.532059] [<ffffffffa03bda3f>] ? bcache_device_link+0xdf/0x110 [bcache]
[ 276.548808] [<ffffffffa03bfa08>] ?
bch_cached_dev_attach+0x478/0x4f0 [bcache]
[ 276.565569] [<ffffffffa03c4a17>] ? bch_cached_dev_store+0x627/0x780 [bcache]
[ 276.582418] [<ffffffff8116783a>] ? alloc_pages_current+0xaa/0x110
[ 276.599341] [<ffffffff81203b15>] ? sysfs_write_file+0xe5/0x170
[ 276.616142] [<ffffffff811887b8>] ? vfs_write+0xb8/0x1a0
[ 276.632607] [<ffffffff811890b1>] ? sys_write+0x51/0x90
[ 276.648671] [<ffffffff8100c072>] ? system_call_fastpath+0x16/0x1b
[ 276.664756] ---[ end trace 9f5d4fcdd0c3edfc ]---
We forget to clear BCACHE_DEV_UNLINK_DONE flag in bcache_device_attach()
function when we attach a backing device first time. After detaching this
backing device, this flag will be true and sysfs_remove_link() isn't called in
bcache_device_unlink(). Then when we attach this backing device again,
sysfs_create_link() will return EEXIST error in bcache_device_link().
So the fix is trival and we clear this flag in bcache_device_link().
Signed-off-by: Zheng Liu <wenqing.lz@xxxxxxxxxx>
Tested-by: Joshua Schmid <jschmid@xxxxxxxx>
---
drivers/md/bcache/super.c | 2 ++
1 file changed, 2 insertions(+)
--- a/drivers/md/bcache/super.c
+++ b/drivers/md/bcache/super.c
@@ -685,6 +685,8 @@ static void bcache_device_link(struct bc
WARN(sysfs_create_link(&d->kobj, &c->kobj, "cache") ||
sysfs_create_link(&c->kobj, &d->kobj, d->name),
"Couldn't create device <-> cache set symlinks");
+
+ clear_bit(BCACHE_DEV_UNLINK_DONE, &d->flags);
}
static void bcache_device_detach(struct bcache_device *d)
---