cregit-Linux how code gets into the kernel

Release 4.10 fs/9p/fid.c

Directory: fs/9p
 * V9FS FID Management
 *  Copyright (C) 2007 by Latchesar Ionkov <>
 *  Copyright (C) 2005, 2006 by Eric Van Hensbergen <>
 *  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
 *  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

#include <linux/module.h>
#include <linux/errno.h>
#include <linux/fs.h>
#include <linux/slab.h>
#include <linux/sched.h>
#include <linux/idr.h>
#include <net/9p/9p.h>
#include <net/9p/client.h>

#include "v9fs.h"
#include "v9fs_vfs.h"
#include "fid.h"

 * v9fs_fid_add - add a fid to a dentry
 * @dentry: dentry that the fid is being added to
 * @fid: fid to add

static inline void __add_fid(struct dentry *dentry, struct p9_fid *fid) { hlist_add_head(&fid->dlist, (struct hlist_head *)&dentry->d_fsdata); }


eric van hensbergeneric van hensbergen1645.71%228.57%
latchesar ionkovlatchesar ionkov1028.57%114.29%
al viroal viro925.71%457.14%

void v9fs_fid_add(struct dentry *dentry, struct p9_fid *fid) { spin_lock(&dentry->d_lock); __add_fid(dentry, fid); spin_unlock(&dentry->d_lock); }


al viroal viro2155.26%233.33%
eric van hensbergeneric van hensbergen1231.58%233.33%
latchesar ionkovlatchesar ionkov513.16%233.33%

/** * v9fs_fid_find - retrieve a fid that belongs to the specified uid * @dentry: dentry to look for fid in * @uid: return fid that belongs to the specified user * @any: if non-zero, return any fid associated with the dentry * */
static struct p9_fid *v9fs_fid_find(struct dentry *dentry, kuid_t uid, int any) { struct p9_fid *fid, *ret; p9_debug(P9_DEBUG_VFS, " dentry: %pd (%p) uid %d any %d\n", dentry, dentry, from_kuid(&init_user_ns, uid), any); ret = NULL; /* we'll recheck under lock if there's anything to look in */ if (dentry->d_fsdata) { struct hlist_head *h = (struct hlist_head *)&dentry->d_fsdata; spin_lock(&dentry->d_lock); hlist_for_each_entry(fid, h, dlist) { if (any || uid_eq(fid->uid, uid)) { ret = fid; break; } } spin_unlock(&dentry->d_lock); } return ret; }


latchesar ionkovlatchesar ionkov6350.40%330.00%
al viroal viro2620.80%440.00%
eric van hensbergeneric van hensbergen2419.20%110.00%
eric w. biedermaneric w. biederman118.80%110.00%
joe perchesjoe perches10.80%110.00%

/* * We need to hold v9ses->rename_sem as long as we hold references * to returned path array. Array element contain pointers to * dentry names. */
static int build_path_from_dentry(struct v9fs_session_info *v9ses, struct dentry *dentry, char ***names) { int n = 0, i; char **wnames; struct dentry *ds; for (ds = dentry; !IS_ROOT(ds); ds = ds->d_parent) n++; wnames = kmalloc(sizeof(char *) * n, GFP_KERNEL); if (!wnames) goto err_out; for (ds = dentry, i = (n-1); i >= 0; i--, ds = ds->d_parent) wnames[i] = (char *)ds->; *names = wnames; return n; err_out: return -ENOMEM; }


aneesh kumaraneesh kumar139100.00%1100.00%

static struct p9_fid *v9fs_fid_lookup_with_uid(struct dentry *dentry, kuid_t uid, int any) { struct dentry *ds; char **wnames, *uname; int i, n, l, clone, access; struct v9fs_session_info *v9ses; struct p9_fid *fid, *old_fid = NULL; v9ses = v9fs_dentry2v9ses(dentry); access = v9ses->flags & V9FS_ACCESS_MASK; fid = v9fs_fid_find(dentry, uid, any); if (fid) return fid; /* * we don't have a matching fid. To do a TWALK we need * parent fid. We need to prevent rename when we want to * look at the parent. */ down_read(&v9ses->rename_sem); ds = dentry->d_parent; fid = v9fs_fid_find(ds, uid, any); if (fid) { /* Found the parent fid do a lookup with that */ fid = p9_client_walk(fid, 1, (char **)&dentry->, 1); goto fid_out; } up_read(&v9ses->rename_sem); /* start from the root and try to do a lookup */ fid = v9fs_fid_find(dentry->d_sb->s_root, uid, any); if (!fid) { /* the user is not attached to the fs yet */ if (access == V9FS_ACCESS_SINGLE) return ERR_PTR(-EPERM); if (v9fs_proto_dotu(v9ses) || v9fs_proto_dotl(v9ses)) uname = NULL; else uname = v9ses->uname; fid = p9_client_attach(v9ses->clnt, NULL, uname, uid, v9ses->aname); if (IS_ERR(fid)) return fid; v9fs_fid_add(dentry->d_sb->s_root, fid); } /* If we are root ourself just return that */ if (dentry->d_sb->s_root == dentry) return fid; /* * Do a multipath walk with attached root. * When walking parent we need to make sure we * don't have a parallel rename happening */ down_read(&v9ses->rename_sem); n = build_path_from_dentry(v9ses, dentry, &wnames); if (n < 0) { fid = ERR_PTR(n); goto err_out; } clone = 1; i = 0; while (i < n) { l = min(n - i, P9_MAXWELEM); /* * We need to hold rename lock when doing a multipath * walk to ensure none of the patch component change */ fid = p9_client_walk(fid, l, &wnames[i], clone); if (IS_ERR(fid)) { if (old_fid) { /* * If we fail, clunk fid which are mapping * to path component and not the last component * of the path. */ p9_client_clunk(old_fid); } kfree(wnames); goto err_out; } old_fid = fid; i += l; clone = 0; } kfree(wnames); fid_out: if (!IS_ERR(fid)) { spin_lock(&dentry->d_lock); if (d_unhashed(dentry)) { spin_unlock(&dentry->d_lock); p9_client_clunk(fid); fid = ERR_PTR(-ENOENT); } else { __add_fid(dentry, fid); spin_unlock(&dentry->d_lock); } } err_out: up_read(&v9ses->rename_sem); return fid; }


latchesar ionkovlatchesar ionkov25753.21%214.29%
aneesh kumaraneesh kumar15031.06%535.71%
al viroal viro5210.77%17.14%
eric van hensbergeneric van hensbergen142.90%321.43%
dan carpenterdan carpenter81.66%17.14%
eric w. biedermaneric w. biederman10.21%17.14%
sripathi kodisripathi kodi10.21%17.14%

/** * v9fs_fid_lookup - lookup for a fid, try to walk if not found * @dentry: dentry to look for fid in * * Look for a fid in the specified dentry for the current user. * If no fid is found, try to create one walking from a fid from the parent * dentry (if it has one), or the root dentry. If the user haven't accessed * the fs yet, attach now and walk from the root. */
struct p9_fid *v9fs_fid_lookup(struct dentry *dentry) { kuid_t uid; int any, access; struct v9fs_session_info *v9ses; v9ses = v9fs_dentry2v9ses(dentry); access = v9ses->flags & V9FS_ACCESS_MASK; switch (access) { case V9FS_ACCESS_SINGLE: case V9FS_ACCESS_USER: case V9FS_ACCESS_CLIENT: uid = current_fsuid(); any = 0; break; case V9FS_ACCESS_ANY: uid = v9ses->uid; any = 1; break; default: uid = INVALID_UID; any = 0; break; } return v9fs_fid_lookup_with_uid(dentry, uid, any); }


aneesh kumaraneesh kumar9797.98%266.67%
eric w. biedermaneric w. biederman22.02%133.33%

struct p9_fid *v9fs_writeback_fid(struct dentry *dentry) { int err; struct p9_fid *fid; fid = clone_fid(v9fs_fid_lookup_with_uid(dentry, GLOBAL_ROOT_UID, 0)); if (IS_ERR(fid)) goto error_out; /* * writeback fid will only be used to write back the * dirty pages. We always request for the open fid in read-write * mode so that a partial page write which result in page * read can work. */ err = p9_client_open(fid, O_RDWR); if (err < 0) { p9_client_clunk(fid); fid = ERR_PTR(err); goto error_out; } error_out: return fid; }


aneesh kumaraneesh kumar7591.46%360.00%
al viroal viro67.32%120.00%
eric w. biedermaneric w. biederman11.22%120.00%

Overall Contributors

aneesh kumaraneesh kumar46344.56%726.92%
latchesar ionkovlatchesar ionkov34132.82%311.54%
al viroal viro11711.26%830.77%
eric van hensbergeneric van hensbergen908.66%311.54%
eric w. biedermaneric w. biederman151.44%13.85%
dan carpenterdan carpenter80.77%13.85%
tejun heotejun heo30.29%13.85%
sripathi kodisripathi kodi10.10%13.85%
joe perchesjoe perches10.10%13.85%
Directory: fs/9p
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