improved parallelization of ZFS discovery and mount #7
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Rudd-O
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Aug 3, 2015
The following panic would occur under certain heavy load: [ 4692.202686] Kernel panic - not syncing: thread ffff8800c4f5dd60 terminating with rrw lock ffff8800da1b9c40 held [ 4692.228053] CPU: 1 PID: 6250 Comm: mmap_deadlock Tainted: P OE 3.18.10 #7 The culprit is that ZFS_EXIT(zsb) would call tsd_exit() every time, which would purge all tsd data for the thread. However, ZFS_ENTER is designed to be reentrant, so we cannot allow ZFS_EXIT to blindly purge tsd data. Instead, we rely on the new behavior of tsd_set. When NULL is passed as the new value to tsd_set, it will automatically remove the tsd entry specified the the key for the current thread. rrw_tsd_key and zfs_allow_log_key already calls tsd_set(key, NULL) when they're done. The zfs_fsyncer_key relied on ZFS_EXIT(zsb) to call tsd_exit() to do clean up. Now we explicitly call tsd_set(key, NULL) on them. Signed-off-by: Chunwei Chen <[email protected]> Signed-off-by: Brian Behlendorf <[email protected]> Closes openzfs#3247
Rudd-O
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Jan 18, 2020
After spa_vdev_remove_aux() is called, the config nvlist is no longer
valid, as it's been replaced by the new one (with the specified device
removed). Therefore any pointers into the nvlist are no longer valid.
So we can't save the result of
`fnvlist_lookup_string(nv, ZPOOL_CONFIG_PATH)` (in vd_path) across the
call to spa_vdev_remove_aux().
Instead, use spa_strdup() to save a copy of the string before calling
spa_vdev_remove_aux.
Found by AddressSanitizer:
ERROR: AddressSanitizer: heap-use-after-free on address ...
READ of size 34 at 0x608000a1fcd0 thread T686
#0 0x7fe88b0c166d (/usr/lib/x86_64-linux-gnu/libasan.so.4+0x5166d)
#1 0x7fe88a5acd6e in spa_strdup spa_misc.c:1447
#2 0x7fe88a688034 in spa_vdev_remove vdev_removal.c:2259
#3 0x55ffbc7748f8 in ztest_vdev_aux_add_remove ztest.c:3229
#4 0x55ffbc769fba in ztest_execute ztest.c:6714
#5 0x55ffbc779a90 in ztest_thread ztest.c:6761
#6 0x7fe889cbc6da in start_thread
#7 0x7fe8899e588e in __clone
0x608000a1fcd0 is located 48 bytes inside of 88-byte region
freed by thread T686 here:
#0 0x7fe88b14e7b8 in __interceptor_free
#1 0x7fe88ae541c5 in nvlist_free nvpair.c:874
#2 0x7fe88ae543ba in nvpair_free nvpair.c:844
#3 0x7fe88ae57400 in nvlist_remove_nvpair nvpair.c:978
#4 0x7fe88a683c81 in spa_vdev_remove_aux vdev_removal.c:185
#5 0x7fe88a68857c in spa_vdev_remove vdev_removal.c:2221
#6 0x55ffbc7748f8 in ztest_vdev_aux_add_remove ztest.c:3229
#7 0x55ffbc769fba in ztest_execute ztest.c:6714
#8 0x55ffbc779a90 in ztest_thread ztest.c:6761
#9 0x7fe889cbc6da in start_thread
Reviewed-by: Brian Behlendorf <[email protected]>
Reviewed-by: Ryan Moeller <[email protected]>
Signed-off-by: Matthew Ahrens <[email protected]>
Closes openzfs#9706
Rudd-O
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Nov 19, 2023
Under certain loads, the following panic is hit:
panic: page fault
KDB: stack backtrace:
#0 0xffffffff805db025 at kdb_backtrace+0x65
#1 0xffffffff8058e86f at vpanic+0x17f
#2 0xffffffff8058e6e3 at panic+0x43
#3 0xffffffff808adc15 at trap_fatal+0x385
#4 0xffffffff808adc6f at trap_pfault+0x4f
#5 0xffffffff80886da8 at calltrap+0x8
#6 0xffffffff80669186 at vgonel+0x186
#7 0xffffffff80669841 at vgone+0x31
#8 0xffffffff8065806d at vfs_hash_insert+0x26d
#9 0xffffffff81a39069 at sfs_vgetx+0x149
#10 0xffffffff81a39c54 at zfsctl_snapdir_lookup+0x1e4
#11 0xffffffff8065a28c at lookup+0x45c
#12 0xffffffff806594b9 at namei+0x259
#13 0xffffffff80676a33 at kern_statat+0xf3
#14 0xffffffff8067712f at sys_fstatat+0x2f
openzfs#15 0xffffffff808ae50c at amd64_syscall+0x10c
openzfs#16 0xffffffff808876bb at fast_syscall_common+0xf8
The page fault occurs because vgonel() will call VOP_CLOSE() for active
vnodes. For this reason, define vop_close for zfsctl_ops_snapshot. While
here, define vop_open for consistency.
After adding the necessary vop, the bug progresses to the following
panic:
panic: VERIFY3(vrecycle(vp) == 1) failed (0 == 1)
cpuid = 17
KDB: stack backtrace:
#0 0xffffffff805e29c5 at kdb_backtrace+0x65
#1 0xffffffff8059620f at vpanic+0x17f
#2 0xffffffff81a27f4a at spl_panic+0x3a
#3 0xffffffff81a3a4d0 at zfsctl_snapshot_inactive+0x40
#4 0xffffffff8066fdee at vinactivef+0xde
#5 0xffffffff80670b8a at vgonel+0x1ea
#6 0xffffffff806711e1 at vgone+0x31
#7 0xffffffff8065fa0d at vfs_hash_insert+0x26d
#8 0xffffffff81a39069 at sfs_vgetx+0x149
#9 0xffffffff81a39c54 at zfsctl_snapdir_lookup+0x1e4
#10 0xffffffff80661c2c at lookup+0x45c
#11 0xffffffff80660e59 at namei+0x259
#12 0xffffffff8067e3d3 at kern_statat+0xf3
#13 0xffffffff8067eacf at sys_fstatat+0x2f
#14 0xffffffff808b5ecc at amd64_syscall+0x10c
openzfs#15 0xffffffff8088f07b at fast_syscall_common+0xf8
This is caused by a race condition that can occur when allocating a new
vnode and adding that vnode to the vfs hash. If the newly created vnode
loses the race when being inserted into the vfs hash, it will not be
recycled as its usecount is greater than zero, hitting the above
assertion.
Fix this by dropping the assertion.
FreeBSD-issue: https://bugs.freebsd.org/bugzilla/show_bug.cgi?id=252700
Reviewed-by: Andriy Gapon <[email protected]>
Reviewed-by: Mateusz Guzik <[email protected]>
Reviewed-by: Alek Pinchuk <[email protected]>
Reviewed-by: Ryan Moeller <[email protected]>
Signed-off-by: Rob Wing <[email protected]>
Co-authored-by: Rob Wing <[email protected]>
Submitted-by: Klara, Inc.
Sponsored-by: rsync.net
Closes openzfs#14501
Rudd-O
pushed a commit
that referenced
this issue
Feb 5, 2024
Under certain loads, the following panic is hit:
panic: page fault
KDB: stack backtrace:
#0 0xffffffff805db025 at kdb_backtrace+0x65
#1 0xffffffff8058e86f at vpanic+0x17f
#2 0xffffffff8058e6e3 at panic+0x43
#3 0xffffffff808adc15 at trap_fatal+0x385
#4 0xffffffff808adc6f at trap_pfault+0x4f
#5 0xffffffff80886da8 at calltrap+0x8
#6 0xffffffff80669186 at vgonel+0x186
#7 0xffffffff80669841 at vgone+0x31
#8 0xffffffff8065806d at vfs_hash_insert+0x26d
#9 0xffffffff81a39069 at sfs_vgetx+0x149
#10 0xffffffff81a39c54 at zfsctl_snapdir_lookup+0x1e4
#11 0xffffffff8065a28c at lookup+0x45c
#12 0xffffffff806594b9 at namei+0x259
#13 0xffffffff80676a33 at kern_statat+0xf3
#14 0xffffffff8067712f at sys_fstatat+0x2f
openzfs#15 0xffffffff808ae50c at amd64_syscall+0x10c
openzfs#16 0xffffffff808876bb at fast_syscall_common+0xf8
The page fault occurs because vgonel() will call VOP_CLOSE() for active
vnodes. For this reason, define vop_close for zfsctl_ops_snapshot. While
here, define vop_open for consistency.
After adding the necessary vop, the bug progresses to the following
panic:
panic: VERIFY3(vrecycle(vp) == 1) failed (0 == 1)
cpuid = 17
KDB: stack backtrace:
#0 0xffffffff805e29c5 at kdb_backtrace+0x65
#1 0xffffffff8059620f at vpanic+0x17f
#2 0xffffffff81a27f4a at spl_panic+0x3a
#3 0xffffffff81a3a4d0 at zfsctl_snapshot_inactive+0x40
#4 0xffffffff8066fdee at vinactivef+0xde
#5 0xffffffff80670b8a at vgonel+0x1ea
#6 0xffffffff806711e1 at vgone+0x31
#7 0xffffffff8065fa0d at vfs_hash_insert+0x26d
#8 0xffffffff81a39069 at sfs_vgetx+0x149
#9 0xffffffff81a39c54 at zfsctl_snapdir_lookup+0x1e4
#10 0xffffffff80661c2c at lookup+0x45c
#11 0xffffffff80660e59 at namei+0x259
#12 0xffffffff8067e3d3 at kern_statat+0xf3
#13 0xffffffff8067eacf at sys_fstatat+0x2f
#14 0xffffffff808b5ecc at amd64_syscall+0x10c
openzfs#15 0xffffffff8088f07b at fast_syscall_common+0xf8
This is caused by a race condition that can occur when allocating a new
vnode and adding that vnode to the vfs hash. If the newly created vnode
loses the race when being inserted into the vfs hash, it will not be
recycled as its usecount is greater than zero, hitting the above
assertion.
Fix this by dropping the assertion.
FreeBSD-issue: https://bugs.freebsd.org/bugzilla/show_bug.cgi?id=252700
Reviewed-by: Andriy Gapon <[email protected]>
Reviewed-by: Mateusz Guzik <[email protected]>
Reviewed-by: Alek Pinchuk <[email protected]>
Reviewed-by: Ryan Moeller <[email protected]>
Signed-off-by: Rob Wing <[email protected]>
Co-authored-by: Rob Wing <[email protected]>
Submitted-by: Klara, Inc.
Sponsored-by: rsync.net
Closes openzfs#14501
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so making it clear the zfs generator stuff is only for the root pool and any other already-discovered pools. we still need a zfs-late service that happens after all the generator-discovered file systems are mounted, but before local-fs.target is done. this service would do zfs import -a, discover what pools got imported this way, and then zfs mount -a of all these pools. the least worst place to do this, so far, looks like between local-fs.target and sysinit.target.
then again I might just want to keep a cache of what filesystems to mount, much like zpool.cache, and update it when file systems are created, destroyed, or their mountpoint property / noauto status, are changed. or, worst case scenario, keep that stored somewhere by updating it on poweroff, making a note of what storage technologies are needed before mounting a certain file system and importing a certain pool. I can thus use the generator to resolve this question altogether, by first importing the right pools in the right order after the right storage technology targets (lvm, dm, md, cryptsetup) have been achieved. I can try this with a VM that has a number of those storage technologies, and a root pool, or no root pool, and to make testing faster, just boot to a sysinit target, see if that succeeded.
then we need a zfs share service
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