1 // SPDX-License-Identifier: GPL-2.0-only 2 /* 3 * This file contians vfs dentry ops for the 9P2000 protocol. 4 * 5 * Copyright (C) 2004 by Eric Van Hensbergen <ericvh@gmail.com> 6 * Copyright (C) 2002 by Ron Minnich <rminnich@lanl.gov> 7 */ 8 9 #include <linux/module.h> 10 #include <linux/errno.h> 11 #include <linux/fs.h> 12 #include <linux/file.h> 13 #include <linux/pagemap.h> 14 #include <linux/stat.h> 15 #include <linux/string.h> 16 #include <linux/namei.h> 17 #include <linux/sched.h> 18 #include <linux/slab.h> 19 #include <net/9p/9p.h> 20 #include <net/9p/client.h> 21 22 #include "v9fs.h" 23 #include "v9fs_vfs.h" 24 #include "fid.h" 25 26 /** 27 * v9fs_cached_dentry_delete - called when dentry refcount equals 0 28 * @dentry: dentry in question 29 * 30 */ 31 static int v9fs_cached_dentry_delete(const struct dentry *dentry) 32 { 33 p9_debug(P9_DEBUG_VFS, " dentry: %pd (%p)\n", 34 dentry, dentry); 35 36 /* Don't cache negative dentries */ 37 if (d_really_is_negative(dentry)) 38 return 1; 39 return 0; 40 } 41 42 /** 43 * v9fs_dentry_release - called when dentry is going to be freed 44 * @dentry: dentry that is being release 45 * 46 */ 47 48 static void v9fs_dentry_release(struct dentry *dentry) 49 { 50 struct hlist_node *p, *n; 51 struct hlist_head head; 52 53 p9_debug(P9_DEBUG_VFS, " dentry: %pd (%p)\n", 54 dentry, dentry); 55 56 spin_lock(&dentry->d_lock); 57 hlist_move_list((struct hlist_head *)&dentry->d_fsdata, &head); 58 spin_unlock(&dentry->d_lock); 59 60 hlist_for_each_safe(p, n, &head) 61 p9_fid_put(hlist_entry(p, struct p9_fid, dlist)); 62 } 63 64 static int __v9fs_lookup_revalidate(struct dentry *dentry, unsigned int flags) 65 { 66 struct p9_fid *fid; 67 struct inode *inode; 68 struct v9fs_inode *v9inode; 69 unsigned int cached; 70 71 if (flags & LOOKUP_RCU) 72 return -ECHILD; 73 74 inode = d_inode(dentry); 75 if (!inode) 76 goto out_valid; 77 78 v9inode = V9FS_I(inode); 79 struct v9fs_session_info *v9ses = v9fs_inode2v9ses(inode); 80 81 cached = v9ses->cache & (CACHE_META | CACHE_LOOSE); 82 83 if (!cached || v9inode->cache_validity & V9FS_INO_INVALID_ATTR) { 84 int retval; 85 struct v9fs_session_info *v9ses; 86 87 fid = v9fs_fid_lookup(dentry); 88 if (IS_ERR(fid)) { 89 p9_debug( 90 P9_DEBUG_VFS, 91 "v9fs_fid_lookup: dentry = %pd (%p), got error %pe\n", 92 dentry, dentry, fid); 93 return PTR_ERR(fid); 94 } 95 96 v9ses = v9fs_inode2v9ses(inode); 97 if (v9fs_proto_dotl(v9ses)) 98 retval = v9fs_refresh_inode_dotl(fid, inode); 99 else 100 retval = v9fs_refresh_inode(fid, inode); 101 p9_fid_put(fid); 102 103 if (retval == -ENOENT) { 104 p9_debug(P9_DEBUG_VFS, "dentry: %pd (%p) invalidated due to ENOENT\n", 105 dentry, dentry); 106 return 0; 107 } 108 if (v9inode->cache_validity & V9FS_INO_INVALID_ATTR) { 109 p9_debug(P9_DEBUG_VFS, "dentry: %pd (%p) invalidated due to type change\n", 110 dentry, dentry); 111 return 0; 112 } 113 if (retval < 0) { 114 p9_debug(P9_DEBUG_VFS, 115 "refresh inode: dentry = %pd (%p), got error %pe\n", 116 dentry, dentry, ERR_PTR(retval)); 117 return retval; 118 } 119 } 120 out_valid: 121 p9_debug(P9_DEBUG_VFS, "dentry: %pd (%p) is valid\n", dentry, dentry); 122 return 1; 123 } 124 125 static int v9fs_lookup_revalidate(struct inode *dir, const struct qstr *name, 126 struct dentry *dentry, unsigned int flags) 127 { 128 return __v9fs_lookup_revalidate(dentry, flags); 129 } 130 131 static bool v9fs_dentry_unalias_trylock(const struct dentry *dentry) 132 { 133 struct v9fs_session_info *v9ses = v9fs_dentry2v9ses(dentry); 134 return down_write_trylock(&v9ses->rename_sem); 135 } 136 137 static void v9fs_dentry_unalias_unlock(const struct dentry *dentry) 138 { 139 struct v9fs_session_info *v9ses = v9fs_dentry2v9ses(dentry); 140 up_write(&v9ses->rename_sem); 141 } 142 143 const struct dentry_operations v9fs_cached_dentry_operations = { 144 .d_revalidate = v9fs_lookup_revalidate, 145 .d_weak_revalidate = __v9fs_lookup_revalidate, 146 .d_delete = v9fs_cached_dentry_delete, 147 .d_release = v9fs_dentry_release, 148 .d_unalias_trylock = v9fs_dentry_unalias_trylock, 149 .d_unalias_unlock = v9fs_dentry_unalias_unlock, 150 }; 151 152 const struct dentry_operations v9fs_dentry_operations = { 153 .d_revalidate = v9fs_lookup_revalidate, 154 .d_weak_revalidate = __v9fs_lookup_revalidate, 155 .d_release = v9fs_dentry_release, 156 .d_unalias_trylock = v9fs_dentry_unalias_trylock, 157 .d_unalias_unlock = v9fs_dentry_unalias_unlock, 158 }; 159