mirror of
https://github.com/AuxXxilium/linux_dsm_epyc7002.git
synced 2025-03-11 23:27:42 +07:00
32a926da5a
Fix a potential deadlock when creating multiple snapshots by holding a reference to struct block_device for the whole lifecycle of every dm device instead of obtaining it independently at each point it is needed. bdget_disk() was called while the device was being suspended, in dm_suspend(). However there could be other devices already suspended, for example when creating additional snapshots of a device. bdget_disk() can wait for IO and allocate memory resulting in waiting for the already-suspended device - deadlock. This patch changes the code so that it gets the reference to struct block_device when struct mapped_device is allocated and initialized in alloc_dev() where it is always OK to allocate memory or wait for I/O. It drops the reference when it is destroyed in free_dev(). Thus there is no call to bdget_disk() while any device is suspended. Previously unlock_fs() was called only if bdev was held. Now it is called unconditionally, but the superfluous calls are harmless because it returns immediately if the filesystem was not previously frozen. This patch also now allows the device size to be changed in a noflush suspend because the bdev is held. This has no adverse effect. Signed-off-by: Mikulas Patocka <mpatocka@redhat.com> Signed-off-by: Alasdair G Kergon <agk@redhat.com> |
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| .. | ||
| raid6test | ||
| .gitignore | ||
| bitmap.c | ||
| bitmap.h | ||
| dm-bio-record.h | ||
| dm-crypt.c | ||
| dm-delay.c | ||
| dm-exception-store.c | ||
| dm-exception-store.h | ||
| dm-io.c | ||
| dm-ioctl.c | ||
| dm-kcopyd.c | ||
| dm-linear.c | ||
| dm-log.c | ||
| dm-mpath.c | ||
| dm-mpath.h | ||
| dm-path-selector.c | ||
| dm-path-selector.h | ||
| dm-raid1.c | ||
| dm-region-hash.c | ||
| dm-round-robin.c | ||
| dm-snap-persistent.c | ||
| dm-snap-transient.c | ||
| dm-snap.c | ||
| dm-stripe.c | ||
| dm-sysfs.c | ||
| dm-table.c | ||
| dm-target.c | ||
| dm-uevent.c | ||
| dm-uevent.h | ||
| dm-zero.c | ||
| dm.c | ||
| dm.h | ||
| faulty.c | ||
| Kconfig | ||
| linear.c | ||
| linear.h | ||
| Makefile | ||
| md.c | ||
| md.h | ||
| mktables.c | ||
| multipath.c | ||
| multipath.h | ||
| raid0.c | ||
| raid0.h | ||
| raid1.c | ||
| raid1.h | ||
| raid5.c | ||
| raid5.h | ||
| raid6algos.c | ||
| raid6altivec.uc | ||
| raid6int.uc | ||
| raid6mmx.c | ||
| raid6recov.c | ||
| raid6sse1.c | ||
| raid6sse2.c | ||
| raid6x86.h | ||
| raid10.c | ||
| raid10.h | ||
| unroll.pl | ||