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[Qemu-block] [PATCH v2 0/7] block: Ignore loosening perm restrictions fa
From: |
Max Reitz |
Subject: |
[Qemu-block] [PATCH v2 0/7] block: Ignore loosening perm restrictions failures |
Date: |
Wed, 8 May 2019 20:25:39 +0200 |
Hi,
This series is mainly a fix for
https://bugzilla.redhat.com/show_bug.cgi?id=1703793. The problem
described there is that mirroring to a gluster volume, then switching
off the volume makes qemu crash. There are two problems here:
(1) file-posix reopens the FD all the time because it thinks the FD it
has is RDONLY. It actually isn’t after the first reopen, we just
forgot to change the internal flags. That’s what patch 1 is for.
(2) Even then, when mirror completes, it drops its write permission on
the FD. This requires a reopen, which will fail if the volume is
down. Mirror doesn’t expect that. Nobody ever expects that
dropping permissions can fail, and rightfully so because that’s what
I think we have generally agreed on.
Therefore, the block layer should hide this error. This is what the
last two patches are for.
The last patch adds two assertions: bdrv_replace_child() (for the old
BDS) and bdrv_inactivate_recurse() assume they only ever drop
assertions. This is now substantiated by these new assertions.
It turns out that this assumption was just plain wrong. Patches 3 to 5
make it right.
v2:
- Patch 1: Set s->perm_change_flags for reopen, too [Kevin]
- Patch 6:
- Rename loosen_restrictions to tighten_restrictions and kind of
invert its meaning [Kevin]
- Assert and document that we cannot return useful information about
whether restrictions are loosened or tightened if the caller wants
to reopen the node [Kevin]
- Patch 7: Handle loosen_restrictions -> tighten_restrictions fallout
git backport-diff output against v1:
Key:
[----] : patches are identical
[####] : number of functional differences between upstream/downstream patch
[down] : patch is downstream-only
The flags [FC] indicate (F)unctional and (C)ontextual differences, respectively
001/7:[0001] [FC] 'file-posix: Update open_flags in raw_set_perm()'
002/7:[----] [--] 'block: Add bdrv_child_refresh_perms()'
003/7:[----] [--] 'block/mirror: Fix child permissions'
004/7:[----] [--] 'block/commit: Drop bdrv_child_try_set_perm()'
005/7:[0018] [FC] 'block: Fix order in bdrv_replace_child()'
^^^^ Confuses my v1 patch with 8aecf1d1bd250a, should be:
[----] [--]
006/7:[down] 'block: Add *tighten_restrictions to *check*_perm()'
^^^^ Commit title has changed, but should be something like:
[0061] [FC]
007/7:[0022] [FC] 'block: Ignore loosening perm restrictions failures'
Max Reitz (7):
file-posix: Update open_flags in raw_set_perm()
block: Add bdrv_child_refresh_perms()
block/mirror: Fix child permissions
block/commit: Drop bdrv_child_try_set_perm()
block: Fix order in bdrv_replace_child()
block: Add *tighten_restrictions to *check*_perm()
block: Ignore loosening perm restrictions failures
include/block/block_int.h | 15 ++++
block.c | 151 ++++++++++++++++++++++++++++++++------
block/commit.c | 2 -
block/file-posix.c | 4 +
block/mirror.c | 32 +++++---
5 files changed, 169 insertions(+), 35 deletions(-)
--
2.20.1
- [Qemu-block] [PATCH v2 0/7] block: Ignore loosening perm restrictions failures,
Max Reitz <=
- [Qemu-block] [PATCH v2 1/7] file-posix: Update open_flags in raw_set_perm(), Max Reitz, 2019/05/08
- [Qemu-block] [PATCH v2 2/7] block: Add bdrv_child_refresh_perms(), Max Reitz, 2019/05/08
- [Qemu-block] [PATCH v2 3/7] block/mirror: Fix child permissions, Max Reitz, 2019/05/08
- [Qemu-block] [PATCH v2 4/7] block/commit: Drop bdrv_child_try_set_perm(), Max Reitz, 2019/05/08
- [Qemu-block] [PATCH v2 5/7] block: Fix order in bdrv_replace_child(), Max Reitz, 2019/05/08
- [Qemu-block] [PATCH v2 7/7] block: Ignore loosening perm restrictions failures, Max Reitz, 2019/05/08
- [Qemu-block] [PATCH v2 6/7] block: Add *tighten_restrictions to *check*_perm(), Max Reitz, 2019/05/08