talos-op-linux/include/asm-generic/fcntl.h, branch v3.0

New kind of open files - "location only".

2011-03-15T06:21:45+00:00

New flag for open(2) - O_PATH. Semantics: * pathname is resolved, but the file itself is _NOT_ opened as far as filesystem is concerned. * almost all operations on the resulting descriptors shall fail with -EBADF. Exceptions are: 1) operations on descriptors themselves (i.e. close(), dup(), dup2(), dup3(), fcntl(fd, F_DUPFD), fcntl(fd, F_DUPFD_CLOEXEC, ...), fcntl(fd, F_GETFD), fcntl(fd, F_SETFD, ...)) 2) fcntl(fd, F_GETFL), for a common non-destructive way to check if descriptor is open 3) "dfd" arguments of ...at(2) syscalls, i.e. the starting points of pathname resolution * closing such descriptor does *NOT* affect dnotify or posix locks. * permissions are checked as usual along the way to file; no permission checks are applied to the file itself. Of course, giving such thing to syscall will result in permission checks (at the moment it means checking that starting point of ....at() is a directory and caller has exec permissions on it). fget() and fget_light() return NULL on such descriptors; use of fget_raw() and fget_raw_light() is needed to get them. That protects existing code from dealing with those things. There are two things still missing (they come in the next commits): one is handling of symlinks (right now we refuse to open them that way; see the next commit for semantics related to those) and another is descriptor passing via SCM_RIGHTS datagrams. Signed-off-by: Al Viro

asm-generic: fcntl: make exported headers use strict posix types

2010-10-09T19:51:43+00:00

All 'pid_t' were changed to '__kernel_pid_t' in a previous commit: make exported headers use strict posix types A number of standard posix types are used in exported headers, which is not allowed if __STRICT_KERNEL_NAMES is defined. In order to get rid of the non-__STRICT_KERNEL_NAMES part and to make sane headers the default, we have to change them all to safe types. but a later change introduced 'pid_t' again: fcntl: add F_[SG]ETOWN_EX This makes asm-generic/fcntl.h d use strict posix types again. Signed-off-by: Lucian Adrian Grijincu Signed-off-by: Andrew Morton Signed-off-by: Arnd Bergmann

vfs: O_* bit numbers uniqueness check

2010-08-11T15:59:02+00:00

The O_* bit numbers are defined in 20+ arch/*, and can silently overlap. Add a compile time check to ensure the uniqueness as suggested by David Miller. Signed-off-by: Wu Fengguang Cc: David Miller Cc: Stephen Rothwell Cc: Al Viro Cc: Christoph Hellwig Cc: Eric Paris Cc: Roland Dreier Cc: Jamie Lokier Cc: Andreas Schwab Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds

fanotify: FMODE_NONOTIFY and __O_SYNC in sparc conflict

2010-07-28T13:58:54+00:00

sparc used the same value as FMODE_NONOTIFY so change FMODE_NONOTIFY to be something unique. Signed-off-by: Wu Fengguang Signed-off-by: Eric Paris

vfs: introduce FMODE_NONOTIFY

2010-07-28T13:58:54+00:00

This is a new f_mode which can only be set by the kernel. It indicates that the fd was opened by fanotify and should not cause future fanotify events. This is needed to prevent fanotify livelock. An example of obvious livelock is from fanotify close events. Process A closes file1 This creates a close event for file1. fanotify opens file1 for Listener X Listener X deals with the event and closes its fd for file1. This creates a close event for file1. fanotify opens file1 for Listener X Listener X deals with the event and closes its fd for file1. This creates a close event for file1. fanotify opens file1 for Listener X Listener X deals with the event and closes its fd for file1. notice a pattern? The fix is to add the FMODE_NONOTIFY bit to the open filp done by the kernel for fanotify. Thus when that file is used it will not generate future events. This patch simply defines the bit. Signed-off-by: Eric Paris

fix up O_SYNC comments

2009-12-17T16:03:24+00:00

Proper Posix O_SYNC handling only made it into 2.6.33, not 2.6.32. Signed-off-by: Christoph Hellwig Signed-off-by: Al Viro

vfs: Implement proper O_SYNC semantics

2009-12-10T14:02:50+00:00

While Linux provided an O_SYNC flag basically since day 1, it took until Linux 2.4.0-test12pre2 to actually get it implemented for filesystems, since that day we had generic_osync_around with only minor changes and the great "For now, when the user asks for O_SYNC, we'll actually give O_DSYNC" comment. This patch intends to actually give us real O_SYNC semantics in addition to the O_DSYNC semantics. After Jan's O_SYNC patches which are required before this patch it's actually surprisingly simple, we just need to figure out when to set the datasync flag to vfs_fsync_range and when not. This patch renames the existing O_SYNC flag to O_DSYNC while keeping it's numerical value to keep binary compatibility, and adds a new real O_SYNC flag. To guarantee backwards compatiblity it is defined as expanding to both the O_DSYNC and the new additional binary flag (__O_SYNC) to make sure we are backwards-compatible when compiled against the new headers. This also means that all places that don't care about the differences can just check O_DSYNC and get the right behaviour for O_SYNC, too - only places that actuall care need to check __O_SYNC in addition. Drivers and network filesystems have been updated in a fail safe way to always do the full sync magic if O_DSYNC is set. The few places setting O_SYNC for lower layers are kept that way for now to stay failsafe. We enforce that O_DSYNC is set when __O_SYNC is set early in the open path to make sure we always get these sane options. Note that parisc really screwed up their headers as they already define a O_DSYNC that has always been a no-op. We try to repair it by using it for the new O_DSYNC and redefinining O_SYNC to send both the traditional O_SYNC numerical value _and_ the O_DSYNC one. Cc: Richard Henderson Cc: Ivan Kokshaysky Cc: Grant Grundler Cc: "David S. Miller" Cc: Ingo Molnar Cc: "H. Peter Anvin" Cc: Thomas Gleixner Cc: Al Viro Cc: Andreas Dilger Acked-by: Trond Myklebust Acked-by: Kyle McMartin Acked-by: Ulrich Drepper Signed-off-by: Christoph Hellwig Signed-off-by: Andrew Morton Signed-off-by: Jan Kara

fcntl: rename F_OWNER_GID to F_OWNER_PGRP

2009-11-18T01:40:33+00:00

This is for consistency with various ioctl() operations that include the suffix "PGRP" in their names, and also for consistency with PRIO_PGRP, used with setpriority() and getpriority(). Also, using PGRP instead of GID avoids confusion with the common abbreviation of "group ID". I'm fine with anything that makes it more consistent, and if PGRP is what is the predominant abbreviation then I see no need to further confuse matters by adding a third one. Signed-off-by: Peter Zijlstra Acked-by: Michael Kerrisk Cc: Ingo Molnar Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds

alpha: fix F_SETOWN_EX and F_GETLK64 conflict

2009-11-12T15:25:56+00:00

Fix a bug in commit ba0a6c9f6fceed11c6a99e8326f0477fe383e6b5 Author: Peter Zijlstra AuthorDate: Wed Sep 23 15:57:03 2009 -0700 Commit: Linus Torvalds CommitDate: Thu Sep 24 07:21:01 2009 -0700 fcntl: add F_[SG]ETOWN_EX In asm-generic/fcntl.h, F_SETOWN_EX and F_GETLK64 both have value 12, and F_GETOWN_EX and F_SETLK64 both have value 13. Reported-by: "Joseph S. Myers" Cc: Richard Henderson Cc: Ivan Kokshaysky Cc: Andreas Schwab Signed-off-by: Peter Zijlstra Acked-by: Ulrich Drepper Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds

fcntl: add F_[SG]ETOWN_EX

2009-09-24T14:21:01+00:00

In order to direct the SIGIO signal to a particular thread of a multi-threaded application we cannot, like suggested by the manpage, put a TID into the regular fcntl(F_SETOWN) call. It will still be send to the whole process of which that thread is part. Since people do want to properly direct SIGIO we introduce F_SETOWN_EX. The need to direct SIGIO comes from self-monitoring profiling such as with perf-counters. Perf-counters uses SIGIO to notify that new sample data is available. If the signal is delivered to the same task that generated the new sample it can augment that data by inspecting the task's user-space state right after it returns from the kernel. This is esp. convenient for interpreted or virtual machine driven environments. Both F_SETOWN_EX and F_GETOWN_EX take a pointer to a struct f_owner_ex as argument: struct f_owner_ex { int type; pid_t pid; }; Where type is one of F_OWNER_TID, F_OWNER_PID or F_OWNER_GID. Signed-off-by: Peter Zijlstra Reviewed-by: Oleg Nesterov Tested-by: stephane eranian Cc: Michael Kerrisk Cc: Roland McGrath Cc: Al Viro Cc: Christoph Hellwig Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds