CIFS flock() locks behave differently than the standard. Give overview
of those differences.
Here is the rendered text:
CIFS details
In Linux kernels up to 5.4, flock() is not propagated over SMB. A file
with such locks will not appear locked for remote clients.
Since Linux 5.5, flock() locks are emulated with SMB byte-range locks
on the entire file. Similarly to NFS, this means that fcntl(2) and
flock() locks interact with one another. Another important side-effect
is that the locks are not advisory anymore: any IO on a locked file
will always fail with EACCES when done from a separate file descriptor.
This difference originates from the design of locks in the SMB proto-
col, which provides mandatory locking semantics.
Remote and mandatory locking semantics may vary with SMB protocol,
mount options and server type. See mount.cifs(8) for additional infor-
mation.
Signed-off-by: Aurelien Aptel <aaptel@suse.com>
Discussion: linux-man <https://lore.kernel.org/linux-man/20210302154831.17000-1-aaptel@suse.com/>
Signed-off-by: Alejandro Colomar <alx.manpages@gmail.com>
Signed-off-by: Michael Kerrisk <mtk.manpages@gmail.com>
In b0b19983d9 we removed
<sys/types.h>. For the same reasons there, remove now <sys/ipc.h>
from many pages.
If someone wonders why <sys/ipc.h> was needed, the reason was to
get all the definitions of IPC_* constants. However, that header
is now included by <sys/msg.h>, so it's not needed anymore to
explicitly include it. Quoting POSIX: "In addition, the
<sys/msg.h> header shall include the <sys/ipc.h> header."
There were some remaining cases where I forgot to remove
<sys/types.h>; remove them now too.
Signed-off-by: Alejandro Colomar <alx.manpages@gmail.com>
Signed-off-by: Michael Kerrisk <mtk.manpages@gmail.com>
AFAICS, all types and constants used by these functions are
defined in <fcntl.h>.
Signed-off-by: Alejandro Colomar <alx.manpages@gmail.com>
Signed-off-by: Michael Kerrisk <mtk.manpages@gmail.com>
A few architectures have a different call signature for pipe().
Since those architectures are the minority, place the prototype
at the end of the SYNOPSIS, rather than the start.
Signed-off-by: Michael Kerrisk <mtk.manpages@gmail.com>
SEE ALSO: move pam_namespace(8) from namespaces(7) to
mount_namespaces(7) (since pam_namespace(8) makes use of
mount namespaces specifically).
Signed-off-by: Michael Kerrisk <mtk.manpages@gmail.com>
Userfaultfd write-protect mode is supported starting from Linux 5.7.
Acked-by: Mike Rapoport <rppt@linux.vnet.ibm.com>
Signed-off-by: Peter Xu <peterx@redhat.com>
[alx: ffix + srcfix]
Signed-off-by: Alejandro Colomar <alx.manpages@gmail.com>
Signed-off-by: Michael Kerrisk <mtk.manpages@gmail.com>
UFFD_FEATURE_THREAD_ID is supported in Linux 4.14.
Acked-by: Mike Rapoport <rppt@linux.vnet.ibm.com>
Signed-off-by: Peter Xu <peterx@redhat.com>
Signed-off-by: Alejandro Colomar <alx.manpages@gmail.com>
Signed-off-by: Michael Kerrisk <mtk.manpages@gmail.com>
Write-protect mode is supported starting from Linux 5.7.
Acked-by: Mike Rapoport <rppt@linux.vnet.ibm.com>
Signed-off-by: Peter Xu <peterx@redhat.com>
Signed-off-by: Alejandro Colomar <alx.manpages@gmail.com>
Signed-off-by: Michael Kerrisk <mtk.manpages@gmail.com>
UFFD_FEATURE_THREAD_ID is supported since Linux 4.14.
Acked-by: Mike Rapoport <rppt@linux.vnet.ibm.com>
Signed-off-by: Peter Xu <peterx@redhat.com>
[alx: srcfix]
Signed-off-by: Alejandro Colomar <alx.manpages@gmail.com>
Signed-off-by: Michael Kerrisk <mtk.manpages@gmail.com>
My initial reading of this was that type modifiers were probably
not supported. But they are, and this is actually documented
further up, in the type modifiers documentation. But to make it
clearer, let's copy the language that printf(3) has in its %n
section.
Signed-off-by: Alyssa Ross <hi@alyssa.is>
Signed-off-by: Alejandro Colomar <alx.manpages@gmail.com>
Signed-off-by: Michael Kerrisk <mtk.manpages@gmail.com>
In this case there's a wrapper provided by libaio,
but this page documents the raw kernel syscall.
Signed-off-by: Alejandro Colomar <alx.manpages@gmail.com>
Signed-off-by: Michael Kerrisk <mtk.manpages@gmail.com>
<linux/unistd.h> is not needed. We need <unistd.h> for syscall(),
and <sys/syscall.h> for SYS_exit_group.
Signed-off-by: Alejandro Colomar <alx.manpages@gmail.com>
Signed-off-by: Michael Kerrisk <mtk.manpages@gmail.com>
Add <linux/fcntl.h>, which contains AT_* definitions used by
execveat().
Signed-off-by: Alejandro Colomar <alx.manpages@gmail.com>
Signed-off-by: Michael Kerrisk <mtk.manpages@gmail.com>
The CLONE_* constants seem to be available from either
<linux/sched.h> or <sched.h>, and since clone3() already
includes <linux/sched.h> for 'struct clone_args', <sched.h>
is not really needed, AFAICS; however, to avoid confusion,
I also included <sched.h> for clone3() for consistency:
clone() is getting CLONE_* from <sched.h>, and it would confuse
the reader if clone3() got the same CLONE_* constants from a
different header.
Signed-off-by: Alejandro Colomar <alx.manpages@gmail.com>
Signed-off-by: Michael Kerrisk <mtk.manpages@gmail.com>
AFAICS, there's no reason to include that.
All of the macros that this function uses
are already defined in the other headers.
Cc: glibc <libc-alpha@sourceware.org>
Signed-off-by: Alejandro Colomar <alx.manpages@gmail.com>
Signed-off-by: Michael Kerrisk <mtk.manpages@gmail.com>
The page didn't specify includes, and the syscalls are extinct, so
instead of adding incomplete information about includes, just
leave it without any includes.
Signed-off-by: Alejandro Colomar <alx.manpages@gmail.com>
Signed-off-by: Michael Kerrisk <mtk.manpages@gmail.com>
Only the include that provides the prototype doesn't need a comment.
Also sort the includes alphabetically.
Signed-off-by: Alejandro Colomar <alx.manpages@gmail.com>
Signed-off-by: Michael Kerrisk <mtk.manpages@gmail.com>
Only the one that provides the prototype doesn't need a comment.
Signed-off-by: Alejandro Colomar <alx.manpages@gmail.com>
Signed-off-by: Michael Kerrisk <mtk.manpages@gmail.com>
<linux/fs.h> doesn't seem to be needed!
Only the include that provides the prototype doesn't need a comment.
Also sort the includes alphabetically.
Signed-off-by: Alejandro Colomar <alx.manpages@gmail.com>
Signed-off-by: Michael Kerrisk <mtk.manpages@gmail.com>
Only the include that provides the prototype doesn't need a comment.
Also sort the includes alphabetically.
Signed-off-by: Alejandro Colomar <alx.manpages@gmail.com>
Signed-off-by: Michael Kerrisk <mtk.manpages@gmail.com>
Aurelien Aptel