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linux/fs/9p/fid.h

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treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 188 Based on 1 normalized pattern(s): this program is free software you can redistribute it and or modify it under the terms of the gnu general public license version 2 as published by the free software foundation this program is distributed in the hope that it will be useful but without any warranty without even the implied warranty of merchantability or fitness for a particular purpose see the gnu general public license for more details you should have received a copy of the gnu general public license along with this program if not write to free software foundation 51 franklin street fifth floor boston ma 02111 1301 usa extracted by the scancode license scanner the SPDX license identifier GPL-2.0-only has been chosen to replace the boilerplate/reference in 27 file(s). Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Reviewed-by: Richard Fontana <rfontana@redhat.com> Reviewed-by: Alexios Zavras <alexios.zavras@intel.com> Reviewed-by: Steve Winslow <swinslow@gmail.com> Reviewed-by: Allison Randal <allison@lohutok.net> Cc: linux-spdx@vger.kernel.org Link: https://lkml.kernel.org/r/20190528170026.981318839@linutronix.de Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2019-05-29 00:57:16 +08:00
/* SPDX-License-Identifier: GPL-2.0-only */
[PATCH] v9fs: debug and support routines This part of the patch contains debug and other misc routines. Signed-off-by: Eric Van Hensbergen <ericvh@gmail.com> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
2005-09-10 04:04:24 +08:00
/*
* V9FS FID Management
*
* Copyright (C) 2005 by Eric Van Hensbergen <ericvh@gmail.com>
*/
fs/9p: Prevent multiple inclusion of same header Add necessary #ifndef #endif blocks to avoid mulitple inclusion of same headers Signed-off-by: Aneesh Kumar K.V <aneesh.kumar@linux.vnet.ibm.com> Signed-off-by: Venkateswararao Jujjuri <jvrao@linux.vnet.ibm.com> Signed-off-by: Eric Van Hensbergen <ericvh@gmail.com>
2011-02-28 19:34:09 +08:00
#ifndef FS_9P_FID_H
#define FS_9P_FID_H
[PATCH] v9fs: debug and support routines This part of the patch contains debug and other misc routines. Signed-off-by: Eric Van Hensbergen <ericvh@gmail.com> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
2005-09-10 04:04:24 +08:00
#include <linux/list.h>
fs/9p: remove writeback fid and fix per-file modes This patch removes the creating of an additional writeback_fid for opened files. The patch addresses problems when files were opened write-only or getattr on files with dirty caches. This patch also incorporates information about cache behavior in the fid for every file. This allows us to reflect cache behavior from mount flags, open mode, and information from the server to inform readahead and writeback behavior. This includes adding support for a 9p semantic that qid.version==0 is used to mark a file as non-cachable which is important for synthetic files. This may have a side-effect of not supporting caching on certain legacy file servers that do not properly set qid.version. There is also now a mount flag which can disable the qid.version behavior. Signed-off-by: Eric Van Hensbergen <ericvh@kernel.org>
2023-03-27 10:06:37 +08:00
#include "v9fs.h"
[PATCH] v9fs: debug and support routines This part of the patch contains debug and other misc routines. Signed-off-by: Eric Van Hensbergen <ericvh@gmail.com> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
2005-09-10 04:04:24 +08:00
fs/9p: remove writeback fid and fix per-file modes This patch removes the creating of an additional writeback_fid for opened files. The patch addresses problems when files were opened write-only or getattr on files with dirty caches. This patch also incorporates information about cache behavior in the fid for every file. This allows us to reflect cache behavior from mount flags, open mode, and information from the server to inform readahead and writeback behavior. This includes adding support for a 9p semantic that qid.version==0 is used to mark a file as non-cachable which is important for synthetic files. This may have a side-effect of not supporting caching on certain legacy file servers that do not properly set qid.version. There is also now a mount flag which can disable the qid.version behavior. Signed-off-by: Eric Van Hensbergen <ericvh@kernel.org>
2023-03-27 10:06:37 +08:00
struct p9_fid *v9fs_fid_find_inode(struct inode *inode, bool want_writeable,
kuid_t uid, bool any);
9p: Reorganization of 9p file system code This patchset moves non-filesystem interfaces of v9fs from fs/9p to net/9p. It moves the transport, packet marshalling and connection layers to net/9p leaving only the VFS related files in fs/9p. This work is being done in preparation for in-kernel 9p servers as well as alternate 9p clients (other than VFS). Signed-off-by: Latchesar Ionkov <lucho@ionkov.net> Signed-off-by: Eric Van Hensbergen <ericvh@gmail.com>
2007-07-11 06:57:28 +08:00
struct p9_fid *v9fs_fid_lookup(struct dentry *dentry);
9p: new helper - v9fs_parent_fid() Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2016-05-30 03:29:26 +08:00
static inline struct p9_fid *v9fs_parent_fid(struct dentry *dentry)
{
return v9fs_fid_lookup(dentry->d_parent);
}
9p fid refcount: cleanup p9_fid_put calls Simplify p9_fid_put cleanup path in many 9p functions since the function is noop on null or error fids. Also make the *_add_fid() helpers "steal" the fid by nulling its pointer, so put after them will be noop. This should lead to no change of behaviour Link: https://lkml.kernel.org/r/20220612085330.1451496-7-asmadeus@codewreck.org Reviewed-by: Tyler Hicks <tyhicks@linux.microsoft.com> Signed-off-by: Dominique Martinet <asmadeus@codewreck.org>
2022-06-12 15:05:39 +08:00
void v9fs_fid_add(struct dentry *dentry, struct p9_fid **fid);
void v9fs_open_fid_add(struct inode *inode, struct p9_fid **fid);
9p: fix braino introduced in "9p: new helper - v9fs_parent_fid()" In v9fs_vfs_rename() we need to clone the parents' fids, not just find them. Spotted-by: Johannes Berg <johannes@sipsolutions.net> Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2016-08-03 23:02:48 +08:00
static inline struct p9_fid *clone_fid(struct p9_fid *fid)
{
return IS_ERR(fid) ? fid : p9_client_walk(fid, 0, NULL, 1);
}
9p: use clone_fid() in a bunch of places it cleans the things up Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2016-08-03 23:12:12 +08:00
static inline struct p9_fid *v9fs_fid_clone(struct dentry *dentry)
{
9p: add refcount to p9_fid struct Fix race issue in fid contention. Eric's and Greg's patch offer a mechanism to fix open-unlink-f*syscall bug in 9p. But there is race issue in fid parallel accesses. As Greg's patch stores all of fids from opened files into according inode, so all the lookup fid ops can retrieve fid from inode preferentially. But there is no mechanism to handle the fid contention issue. For example, there are two threads get the same fid in the same time and one of them clunk the fid before the other thread ready to discard the fid. In this scenario, it will lead to some fatal problems, even kernel core dump. I introduce a mechanism to fix this race issue. A counter field introduced into p9_fid struct to store the reference counter to the fid. When a fid is allocated from the inode or dentry, the counter will increase, and will decrease at the end of its occupation. It is guaranteed that the fid won't be clunked before the reference counter go down to 0, then we can avoid the clunked fid to be used. tests: race issue test from the old test case: for file in {01..50}; do touch f.${file}; done seq 1 1000 | xargs -n 1 -P 50 -I{} cat f.* > /dev/null open-unlink-f*syscall test: I have tested for f*syscall include: ftruncate fstat fchown fchmod faccessat. Link: http://lkml.kernel.org/r/20200923141146.90046-5-jianyong.wu@arm.com Fixes: 478ba09edc1f ("fs/9p: search open fids first") Signed-off-by: Jianyong Wu <jianyong.wu@arm.com> Signed-off-by: Dominique Martinet <asmadeus@codewreck.org>
2020-09-23 22:11:46 +08:00
struct p9_fid *fid, *nfid;
fid = v9fs_fid_lookup(dentry);
if (!fid || IS_ERR(fid))
return fid;
9p: apply review requests for fid refcounting Fix style issues in parent commit ("apply review requests for fid refcounting"), no functional change. Link: http://lkml.kernel.org/r/1605802012-31133-2-git-send-email-asmadeus@codewreck.org Fixes: 6636b6dcc3db ("9p: add refcount to p9_fid struct") Signed-off-by: Dominique Martinet <asmadeus@codewreck.org>
2020-11-03 16:35:57 +08:00
nfid = clone_fid(fid);
9p fid refcount: add p9_fid_get/put wrappers I was recently reminded that it is not clear that p9_client_clunk() was actually just decrementing refcount and clunking only when that reaches zero: make it clear through a set of helpers. This will also allow instrumenting refcounting better for debugging next patch Link: https://lkml.kernel.org/r/20220612085330.1451496-5-asmadeus@codewreck.org Reviewed-by: Tyler Hicks <tyhicks@linux.microsoft.com> Reviewed-by: Christian Schoenebeck <linux_oss@crudebyte.com> Signed-off-by: Dominique Martinet <asmadeus@codewreck.org>
2022-06-12 12:42:32 +08:00
p9_fid_put(fid);
9p: add refcount to p9_fid struct Fix race issue in fid contention. Eric's and Greg's patch offer a mechanism to fix open-unlink-f*syscall bug in 9p. But there is race issue in fid parallel accesses. As Greg's patch stores all of fids from opened files into according inode, so all the lookup fid ops can retrieve fid from inode preferentially. But there is no mechanism to handle the fid contention issue. For example, there are two threads get the same fid in the same time and one of them clunk the fid before the other thread ready to discard the fid. In this scenario, it will lead to some fatal problems, even kernel core dump. I introduce a mechanism to fix this race issue. A counter field introduced into p9_fid struct to store the reference counter to the fid. When a fid is allocated from the inode or dentry, the counter will increase, and will decrease at the end of its occupation. It is guaranteed that the fid won't be clunked before the reference counter go down to 0, then we can avoid the clunked fid to be used. tests: race issue test from the old test case: for file in {01..50}; do touch f.${file}; done seq 1 1000 | xargs -n 1 -P 50 -I{} cat f.* > /dev/null open-unlink-f*syscall test: I have tested for f*syscall include: ftruncate fstat fchown fchmod faccessat. Link: http://lkml.kernel.org/r/20200923141146.90046-5-jianyong.wu@arm.com Fixes: 478ba09edc1f ("fs/9p: search open fids first") Signed-off-by: Jianyong Wu <jianyong.wu@arm.com> Signed-off-by: Dominique Martinet <asmadeus@codewreck.org>
2020-09-23 22:11:46 +08:00
return nfid;
9p: use clone_fid() in a bunch of places it cleans the things up Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2016-08-03 23:12:12 +08:00
}
fs/9p: remove writeback fid and fix per-file modes This patch removes the creating of an additional writeback_fid for opened files. The patch addresses problems when files were opened write-only or getattr on files with dirty caches. This patch also incorporates information about cache behavior in the fid for every file. This allows us to reflect cache behavior from mount flags, open mode, and information from the server to inform readahead and writeback behavior. This includes adding support for a 9p semantic that qid.version==0 is used to mark a file as non-cachable which is important for synthetic files. This may have a side-effect of not supporting caching on certain legacy file servers that do not properly set qid.version. There is also now a mount flag which can disable the qid.version behavior. Signed-off-by: Eric Van Hensbergen <ericvh@kernel.org>
2023-03-27 10:06:37 +08:00
/**
* v9fs_fid_addmodes - add cache flags to fid mode (for client use only)
* @fid: fid to augment
* @s_flags: session info mount flags
* @s_cache: session info cache flags
* @f_flags: unix open flags
*
* make sure mode reflects flags of underlying mounts
* also qid.version == 0 reflects a synthetic or legacy file system
* NOTE: these are set after open so only reflect 9p client not
* underlying file system on server.
*/
fs/9p: fix type mismatch in file cache mode helper There were two flags (s_flags and s_cache) which had incorrect signed type in the parameters of the file cache mode helper function. Cc: stable@vger.kernel.org Fixes: 1543b4c5071c ("fs/9p: remove writeback fid and fix per-file modes") Reviewed-by: Dominique Martinet <asmadeus@codewreck.org> Signed-off-by: Eric Van Hensbergen <ericvh@kernel.org>
2023-07-20 00:22:32 +08:00
static inline void v9fs_fid_add_modes(struct p9_fid *fid, unsigned int s_flags,
unsigned int s_cache, unsigned int f_flags)
fs/9p: remove writeback fid and fix per-file modes This patch removes the creating of an additional writeback_fid for opened files. The patch addresses problems when files were opened write-only or getattr on files with dirty caches. This patch also incorporates information about cache behavior in the fid for every file. This allows us to reflect cache behavior from mount flags, open mode, and information from the server to inform readahead and writeback behavior. This includes adding support for a 9p semantic that qid.version==0 is used to mark a file as non-cachable which is important for synthetic files. This may have a side-effect of not supporting caching on certain legacy file servers that do not properly set qid.version. There is also now a mount flag which can disable the qid.version behavior. Signed-off-by: Eric Van Hensbergen <ericvh@kernel.org>
2023-03-27 10:06:37 +08:00
{
if (fid->qid.type != P9_QTFILE)
return;
if ((!s_cache) ||
((fid->qid.version == 0) && !(s_flags & V9FS_IGNORE_QV)) ||
(s_flags & V9FS_DIRECT_IO) || (f_flags & O_DIRECT)) {
fid->mode |= P9L_DIRECT; /* no read or write cache */
fs/9p: Rework cache modes and add new options to Documentation Switch cache modes to a bit-mask and use legacy cache names as shortcuts. Update documentation to include information on both shortcuts and bitmasks. This patch also fixes missing guards related to fscache. Update the documentation for new mount flags and cache modes. Signed-off-by: Eric Van Hensbergen <ericvh@kernel.org>
2023-03-27 09:53:10 +08:00
} else if ((!(s_cache & CACHE_WRITEBACK)) ||
fs/9p: fix typo in comparison logic for cache mode There appears to be a typo in the comparison statement for the logic which sets a file's cache mode based on mount flags. Cc: stable@vger.kernel.org Fixes: 1543b4c5071c ("fs/9p: remove writeback fid and fix per-file modes") Reviewed-by: Christian Schoenebeck <linux_oss@crudebyte.com> Reviewed-by: Dominique Martinet <asmadeus@codewreck.org> Signed-off-by: Eric Van Hensbergen <ericvh@kernel.org>
2023-07-20 00:22:31 +08:00
(f_flags & O_DSYNC) || (s_flags & V9FS_SYNC)) {
fs/9p: remove writeback fid and fix per-file modes This patch removes the creating of an additional writeback_fid for opened files. The patch addresses problems when files were opened write-only or getattr on files with dirty caches. This patch also incorporates information about cache behavior in the fid for every file. This allows us to reflect cache behavior from mount flags, open mode, and information from the server to inform readahead and writeback behavior. This includes adding support for a 9p semantic that qid.version==0 is used to mark a file as non-cachable which is important for synthetic files. This may have a side-effect of not supporting caching on certain legacy file servers that do not properly set qid.version. There is also now a mount flag which can disable the qid.version behavior. Signed-off-by: Eric Van Hensbergen <ericvh@kernel.org>
2023-03-27 10:06:37 +08:00
fid->mode |= P9L_NOWRITECACHE;
}
}
fs/9p: Prevent multiple inclusion of same header Add necessary #ifndef #endif blocks to avoid mulitple inclusion of same headers Signed-off-by: Aneesh Kumar K.V <aneesh.kumar@linux.vnet.ibm.com> Signed-off-by: Venkateswararao Jujjuri <jvrao@linux.vnet.ibm.com> Signed-off-by: Eric Van Hensbergen <ericvh@gmail.com>
2011-02-28 19:34:09 +08:00
#endif
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