From: Olaf Seibert <1865048@bugs.launchpad.net>
To: qemu-devel@nongnu.org
Subject: [Bug 1865048] [NEW] qemu-img --force-share does not disable file locking
Date: Thu, 27 Feb 2020 15:33:56 -0000 [thread overview]
Message-ID: <158281763694.13572.4793000469968260846.malonedeb@gac.canonical.com> (raw)
Public bug reported:
The new option "--force-share" for qemu-img does not disable file
locking.
I tried it with version qemu-img version 2.11.1(Debian 1:2.11+dfsg-
1ubuntu7.21~cloud0) and I traced the source code of the current git
trunk.
Sample to demonstrate:
# strace qemu-img info --force-share testfile.qcow2 2>&1 | grep F_RDLCK
fcntl(11, F_OFD_SETLK, {l_type=F_RDLCK, l_whence=SEEK_SET, l_start=100, l_len=1}) = 0
fcntl(11, F_OFD_SETLK, {l_type=F_RDLCK, l_whence=SEEK_SET, l_start=100, l_len=1}) = 0
fcntl(11, F_OFD_SETLK, {l_type=F_RDLCK, l_whence=SEEK_SET, l_start=100, l_len=1}) = 0
fcntl(11, F_OFD_SETLK, {l_type=F_RDLCK, l_whence=SEEK_SET, l_start=100, l_len=1}) = 0
fcntl(11, F_OFD_SETLK, {l_type=F_RDLCK, l_whence=SEEK_SET, l_start=100, l_len=1}) = 0
fcntl(11, F_OFD_SETLK, {l_type=F_RDLCK, l_whence=SEEK_SET, l_start=100, l_len=1}) = 0
fcntl(11, F_OFD_SETLK, {l_type=F_RDLCK, l_whence=SEEK_SET, l_start=100, l_len=1}) = 0
fcntl(11, F_OFD_SETLK, {l_type=F_RDLCK, l_whence=SEEK_SET, l_start=100, l_len=1}) = 0
fcntl(11, F_OFD_SETLK, {l_type=F_RDLCK, l_whence=SEEK_SET, l_start=100, l_len=1}) = 0
I traced the passing of the --force-share option through the source code
(I used commit 6c599282f8 as of Mon Feb 17 13:32:25 2020 +0000)
qemu-img.c:img_info()
force_share = true;
qemu-img.c:collect_image_info_list(force_share)
qemu-img.c:img_open(force_share)
qemu-img.c:img_open_file(force_share)
qdict_put_bool(options, BDRV_OPT_FORCE_SHARE, true);
block/block-backend.c:blk_new_open(options)
block.c:bdrv_open(options)
block.c:bdrv_open_inheritoptions()
block.c:bdrv_open_common(options)
bs->force_share = qemu_opt_get_bool(opts, BDRV_OPT_FORCE_SHARE, false);
block.c:bdrv_open_driver(bs)
include/block/block_int.h:int (*bdrv_file_open)(BlockDriverState *bs, QDict *options, int flags,
block/file-posix.c:.bdrv_file_open = raw_open,
block/file-posix.c:raw_open_common(bs)
locking = qapi_enum_parse(&OnOffAuto_lookup,
qemu_opt_get(opts, "locking"),
ON_OFF_AUTO_AUTO, &local_err);
ignoring bs->force_share
At the end, bs->force_share is ignored in determining the locking value.
** Affects: qemu
Importance: Undecided
Status: New
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https://bugs.launchpad.net/bugs/1865048
Title:
qemu-img --force-share does not disable file locking
Status in QEMU:
New
Bug description:
The new option "--force-share" for qemu-img does not disable file
locking.
I tried it with version qemu-img version 2.11.1(Debian 1:2.11+dfsg-
1ubuntu7.21~cloud0) and I traced the source code of the current git
trunk.
Sample to demonstrate:
# strace qemu-img info --force-share testfile.qcow2 2>&1 | grep F_RDLCK
fcntl(11, F_OFD_SETLK, {l_type=F_RDLCK, l_whence=SEEK_SET, l_start=100, l_len=1}) = 0
fcntl(11, F_OFD_SETLK, {l_type=F_RDLCK, l_whence=SEEK_SET, l_start=100, l_len=1}) = 0
fcntl(11, F_OFD_SETLK, {l_type=F_RDLCK, l_whence=SEEK_SET, l_start=100, l_len=1}) = 0
fcntl(11, F_OFD_SETLK, {l_type=F_RDLCK, l_whence=SEEK_SET, l_start=100, l_len=1}) = 0
fcntl(11, F_OFD_SETLK, {l_type=F_RDLCK, l_whence=SEEK_SET, l_start=100, l_len=1}) = 0
fcntl(11, F_OFD_SETLK, {l_type=F_RDLCK, l_whence=SEEK_SET, l_start=100, l_len=1}) = 0
fcntl(11, F_OFD_SETLK, {l_type=F_RDLCK, l_whence=SEEK_SET, l_start=100, l_len=1}) = 0
fcntl(11, F_OFD_SETLK, {l_type=F_RDLCK, l_whence=SEEK_SET, l_start=100, l_len=1}) = 0
fcntl(11, F_OFD_SETLK, {l_type=F_RDLCK, l_whence=SEEK_SET, l_start=100, l_len=1}) = 0
I traced the passing of the --force-share option through the source
code (I used commit 6c599282f8 as of Mon Feb 17 13:32:25 2020 +0000)
qemu-img.c:img_info()
force_share = true;
qemu-img.c:collect_image_info_list(force_share)
qemu-img.c:img_open(force_share)
qemu-img.c:img_open_file(force_share)
qdict_put_bool(options, BDRV_OPT_FORCE_SHARE, true);
block/block-backend.c:blk_new_open(options)
block.c:bdrv_open(options)
block.c:bdrv_open_inheritoptions()
block.c:bdrv_open_common(options)
bs->force_share = qemu_opt_get_bool(opts, BDRV_OPT_FORCE_SHARE, false);
block.c:bdrv_open_driver(bs)
include/block/block_int.h:int (*bdrv_file_open)(BlockDriverState *bs, QDict *options, int flags,
block/file-posix.c:.bdrv_file_open = raw_open,
block/file-posix.c:raw_open_common(bs)
locking = qapi_enum_parse(&OnOffAuto_lookup,
qemu_opt_get(opts, "locking"),
ON_OFF_AUTO_AUTO, &local_err);
ignoring bs->force_share
At the end, bs->force_share is ignored in determining the locking
value.
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next reply other threads:[~2020-02-27 15:41 UTC|newest]
Thread overview: 4+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-02-27 15:33 Olaf Seibert [this message]
2020-02-27 17:23 ` [Bug 1865048] Re: qemu-img --force-share does not disable file locking Max Reitz
2020-02-28 9:07 ` Olaf Seibert
2020-02-28 14:19 ` Max Reitz
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