1c82ee6d3SThomas Gleixner // SPDX-License-Identifier: GPL-2.0-or-later 290586523SEric Paris /* 390586523SEric Paris * Copyright (C) 2008 Red Hat, Inc., Eric Paris <eparis@redhat.com> 490586523SEric Paris */ 590586523SEric Paris 690586523SEric Paris #include <linux/dcache.h> 790586523SEric Paris #include <linux/fs.h> 85a0e3ad6STejun Heo #include <linux/gfp.h> 990586523SEric Paris #include <linux/init.h> 1090586523SEric Paris #include <linux/module.h> 117131485aSEric Paris #include <linux/mount.h> 1290586523SEric Paris #include <linux/srcu.h> 1390586523SEric Paris 1490586523SEric Paris #include <linux/fsnotify_backend.h> 1590586523SEric Paris #include "fsnotify.h" 1690586523SEric Paris 1790586523SEric Paris /* 183be25f49SEric Paris * Clear all of the marks on an inode when it is being evicted from core 193be25f49SEric Paris */ 203be25f49SEric Paris void __fsnotify_inode_delete(struct inode *inode) 213be25f49SEric Paris { 223be25f49SEric Paris fsnotify_clear_marks_by_inode(inode); 233be25f49SEric Paris } 243be25f49SEric Paris EXPORT_SYMBOL_GPL(__fsnotify_inode_delete); 253be25f49SEric Paris 26ca9c726eSAndreas Gruenbacher void __fsnotify_vfsmount_delete(struct vfsmount *mnt) 27ca9c726eSAndreas Gruenbacher { 28ca9c726eSAndreas Gruenbacher fsnotify_clear_marks_by_mount(mnt); 29ca9c726eSAndreas Gruenbacher } 30ca9c726eSAndreas Gruenbacher 31ebb3b47eSJan Kara /** 32ebb3b47eSJan Kara * fsnotify_unmount_inodes - an sb is unmounting. handle any watched inodes. 33ebb3b47eSJan Kara * @sb: superblock being unmounted. 34ebb3b47eSJan Kara * 35ebb3b47eSJan Kara * Called during unmount with no locks held, so needs to be safe against 36ebb3b47eSJan Kara * concurrent modifiers. We temporarily drop sb->s_inode_list_lock and CAN block. 37ebb3b47eSJan Kara */ 381e6cb723SAmir Goldstein static void fsnotify_unmount_inodes(struct super_block *sb) 39ebb3b47eSJan Kara { 40ebb3b47eSJan Kara struct inode *inode, *iput_inode = NULL; 41ebb3b47eSJan Kara 42ebb3b47eSJan Kara spin_lock(&sb->s_inode_list_lock); 43ebb3b47eSJan Kara list_for_each_entry(inode, &sb->s_inodes, i_sb_list) { 44ebb3b47eSJan Kara /* 45ebb3b47eSJan Kara * We cannot __iget() an inode in state I_FREEING, 46ebb3b47eSJan Kara * I_WILL_FREE, or I_NEW which is fine because by that point 47ebb3b47eSJan Kara * the inode cannot have any associated watches. 48ebb3b47eSJan Kara */ 49ebb3b47eSJan Kara spin_lock(&inode->i_lock); 50ebb3b47eSJan Kara if (inode->i_state & (I_FREEING|I_WILL_FREE|I_NEW)) { 51ebb3b47eSJan Kara spin_unlock(&inode->i_lock); 52ebb3b47eSJan Kara continue; 53ebb3b47eSJan Kara } 54ebb3b47eSJan Kara 55ebb3b47eSJan Kara /* 56ebb3b47eSJan Kara * If i_count is zero, the inode cannot have any watches and 571751e8a6SLinus Torvalds * doing an __iget/iput with SB_ACTIVE clear would actually 58ebb3b47eSJan Kara * evict all inodes with zero i_count from icache which is 59ebb3b47eSJan Kara * unnecessarily violent and may in fact be illegal to do. 60ebb3b47eSJan Kara */ 61ebb3b47eSJan Kara if (!atomic_read(&inode->i_count)) { 62ebb3b47eSJan Kara spin_unlock(&inode->i_lock); 63ebb3b47eSJan Kara continue; 64ebb3b47eSJan Kara } 65ebb3b47eSJan Kara 66ebb3b47eSJan Kara __iget(inode); 67ebb3b47eSJan Kara spin_unlock(&inode->i_lock); 68ebb3b47eSJan Kara spin_unlock(&sb->s_inode_list_lock); 69ebb3b47eSJan Kara 70ebb3b47eSJan Kara if (iput_inode) 71ebb3b47eSJan Kara iput(iput_inode); 72ebb3b47eSJan Kara 73ebb3b47eSJan Kara /* for each watch, send FS_UNMOUNT and then remove it */ 74ebb3b47eSJan Kara fsnotify(inode, FS_UNMOUNT, inode, FSNOTIFY_EVENT_INODE, NULL, 0); 75ebb3b47eSJan Kara 76ebb3b47eSJan Kara fsnotify_inode_delete(inode); 77ebb3b47eSJan Kara 78ebb3b47eSJan Kara iput_inode = inode; 79ebb3b47eSJan Kara 80ebb3b47eSJan Kara spin_lock(&sb->s_inode_list_lock); 81ebb3b47eSJan Kara } 82ebb3b47eSJan Kara spin_unlock(&sb->s_inode_list_lock); 83ebb3b47eSJan Kara 84ebb3b47eSJan Kara if (iput_inode) 85ebb3b47eSJan Kara iput(iput_inode); 86721fb6fbSJan Kara /* Wait for outstanding inode references from connectors */ 87721fb6fbSJan Kara wait_var_event(&sb->s_fsnotify_inode_refs, 88721fb6fbSJan Kara !atomic_long_read(&sb->s_fsnotify_inode_refs)); 89ebb3b47eSJan Kara } 90ebb3b47eSJan Kara 911e6cb723SAmir Goldstein void fsnotify_sb_delete(struct super_block *sb) 921e6cb723SAmir Goldstein { 931e6cb723SAmir Goldstein fsnotify_unmount_inodes(sb); 941e6cb723SAmir Goldstein fsnotify_clear_marks_by_sb(sb); 951e6cb723SAmir Goldstein } 961e6cb723SAmir Goldstein 973be25f49SEric Paris /* 984d8e7055SAmir Goldstein * fsnotify_nameremove - a filename was removed from a directory 994d8e7055SAmir Goldstein * 1004d8e7055SAmir Goldstein * This is mostly called under parent vfs inode lock so name and 1014d8e7055SAmir Goldstein * dentry->d_parent should be stable. However there are some corner cases where 1024d8e7055SAmir Goldstein * inode lock is not held. So to be on the safe side and be reselient to future 1034d8e7055SAmir Goldstein * callers and out of tree users of d_delete(), we do not assume that d_parent 1044d8e7055SAmir Goldstein * and d_name are stable and we use dget_parent() and 1054d8e7055SAmir Goldstein * take_dentry_name_snapshot() to grab stable references. 1064d8e7055SAmir Goldstein */ 1074d8e7055SAmir Goldstein void fsnotify_nameremove(struct dentry *dentry, int isdir) 1084d8e7055SAmir Goldstein { 1094d8e7055SAmir Goldstein struct dentry *parent; 1104d8e7055SAmir Goldstein struct name_snapshot name; 1114d8e7055SAmir Goldstein __u32 mask = FS_DELETE; 1124d8e7055SAmir Goldstein 1134d8e7055SAmir Goldstein /* d_delete() of pseudo inode? (e.g. __ns_get_path() playing tricks) */ 1144d8e7055SAmir Goldstein if (IS_ROOT(dentry)) 1154d8e7055SAmir Goldstein return; 1164d8e7055SAmir Goldstein 1174d8e7055SAmir Goldstein if (isdir) 1184d8e7055SAmir Goldstein mask |= FS_ISDIR; 1194d8e7055SAmir Goldstein 1204d8e7055SAmir Goldstein parent = dget_parent(dentry); 1214d8e7055SAmir Goldstein /* Avoid unneeded take_dentry_name_snapshot() */ 1224d8e7055SAmir Goldstein if (!(d_inode(parent)->i_fsnotify_mask & FS_DELETE) && 1234d8e7055SAmir Goldstein !(dentry->d_sb->s_fsnotify_mask & FS_DELETE)) 1244d8e7055SAmir Goldstein goto out_dput; 1254d8e7055SAmir Goldstein 1264d8e7055SAmir Goldstein take_dentry_name_snapshot(&name, dentry); 1274d8e7055SAmir Goldstein 1284d8e7055SAmir Goldstein fsnotify(d_inode(parent), mask, d_inode(dentry), FSNOTIFY_EVENT_INODE, 129d4c60811SLinus Torvalds &name.name, 0); 1304d8e7055SAmir Goldstein 1314d8e7055SAmir Goldstein release_dentry_name_snapshot(&name); 1324d8e7055SAmir Goldstein 1334d8e7055SAmir Goldstein out_dput: 1344d8e7055SAmir Goldstein dput(parent); 1354d8e7055SAmir Goldstein } 1364d8e7055SAmir Goldstein EXPORT_SYMBOL(fsnotify_nameremove); 1374d8e7055SAmir Goldstein 1384d8e7055SAmir Goldstein /* 139c28f7e56SEric Paris * Given an inode, first check if we care what happens to our children. Inotify 140c28f7e56SEric Paris * and dnotify both tell their parents about events. If we care about any event 141c28f7e56SEric Paris * on a child we run all of our children and set a dentry flag saying that the 142c28f7e56SEric Paris * parent cares. Thus when an event happens on a child it can quickly tell if 143c28f7e56SEric Paris * if there is a need to find a parent and send the event to the parent. 144c28f7e56SEric Paris */ 145c28f7e56SEric Paris void __fsnotify_update_child_dentry_flags(struct inode *inode) 146c28f7e56SEric Paris { 147c28f7e56SEric Paris struct dentry *alias; 148c28f7e56SEric Paris int watched; 149c28f7e56SEric Paris 150c28f7e56SEric Paris if (!S_ISDIR(inode->i_mode)) 151c28f7e56SEric Paris return; 152c28f7e56SEric Paris 153c28f7e56SEric Paris /* determine if the children should tell inode about their events */ 154c28f7e56SEric Paris watched = fsnotify_inode_watches_children(inode); 155c28f7e56SEric Paris 156873feea0SNick Piggin spin_lock(&inode->i_lock); 157c28f7e56SEric Paris /* run all of the dentries associated with this inode. Since this is a 158c28f7e56SEric Paris * directory, there damn well better only be one item on this list */ 159946e51f2SAl Viro hlist_for_each_entry(alias, &inode->i_dentry, d_u.d_alias) { 160c28f7e56SEric Paris struct dentry *child; 161c28f7e56SEric Paris 162c28f7e56SEric Paris /* run all of the children of the original inode and fix their 163c28f7e56SEric Paris * d_flags to indicate parental interest (their parent is the 164c28f7e56SEric Paris * original inode) */ 1652fd6b7f5SNick Piggin spin_lock(&alias->d_lock); 166946e51f2SAl Viro list_for_each_entry(child, &alias->d_subdirs, d_child) { 167c28f7e56SEric Paris if (!child->d_inode) 168c28f7e56SEric Paris continue; 169c28f7e56SEric Paris 1702fd6b7f5SNick Piggin spin_lock_nested(&child->d_lock, DENTRY_D_LOCK_NESTED); 171c28f7e56SEric Paris if (watched) 172c28f7e56SEric Paris child->d_flags |= DCACHE_FSNOTIFY_PARENT_WATCHED; 173c28f7e56SEric Paris else 174c28f7e56SEric Paris child->d_flags &= ~DCACHE_FSNOTIFY_PARENT_WATCHED; 175c28f7e56SEric Paris spin_unlock(&child->d_lock); 176c28f7e56SEric Paris } 1772fd6b7f5SNick Piggin spin_unlock(&alias->d_lock); 178c28f7e56SEric Paris } 179873feea0SNick Piggin spin_unlock(&inode->i_lock); 180c28f7e56SEric Paris } 181c28f7e56SEric Paris 182c28f7e56SEric Paris /* Notify this dentry's parent about a child's events. */ 18312c7f9dcSAl Viro int __fsnotify_parent(const struct path *path, struct dentry *dentry, __u32 mask) 184c28f7e56SEric Paris { 185c28f7e56SEric Paris struct dentry *parent; 186c28f7e56SEric Paris struct inode *p_inode; 18752420392SEric Paris int ret = 0; 188c28f7e56SEric Paris 18972acc854SAndreas Gruenbacher if (!dentry) 1902069601bSLinus Torvalds dentry = path->dentry; 19128c60e37SEric Paris 192c28f7e56SEric Paris if (!(dentry->d_flags & DCACHE_FSNOTIFY_PARENT_WATCHED)) 19352420392SEric Paris return 0; 194c28f7e56SEric Paris 1954d4eb366SChristoph Hellwig parent = dget_parent(dentry); 196c28f7e56SEric Paris p_inode = parent->d_inode; 197c28f7e56SEric Paris 198b469e7e4SAmir Goldstein if (unlikely(!fsnotify_inode_watches_children(p_inode))) { 1994d4eb366SChristoph Hellwig __fsnotify_update_child_dentry_flags(p_inode); 200b469e7e4SAmir Goldstein } else if (p_inode->i_fsnotify_mask & mask & ALL_FSNOTIFY_EVENTS) { 20149d31c2fSAl Viro struct name_snapshot name; 20249d31c2fSAl Viro 203c28f7e56SEric Paris /* we are notifying a parent so come up with the new mask which 204c28f7e56SEric Paris * specifies these are events which came from a child. */ 205c28f7e56SEric Paris mask |= FS_EVENT_ON_CHILD; 206c28f7e56SEric Paris 20749d31c2fSAl Viro take_dentry_name_snapshot(&name, dentry); 2082069601bSLinus Torvalds if (path) 20952420392SEric Paris ret = fsnotify(p_inode, mask, path, FSNOTIFY_EVENT_PATH, 21025b229dfSAl Viro &name.name, 0); 21128c60e37SEric Paris else 21252420392SEric Paris ret = fsnotify(p_inode, mask, dentry->d_inode, FSNOTIFY_EVENT_INODE, 21325b229dfSAl Viro &name.name, 0); 21449d31c2fSAl Viro release_dentry_name_snapshot(&name); 215c28f7e56SEric Paris } 216c28f7e56SEric Paris 217c28f7e56SEric Paris dput(parent); 21852420392SEric Paris 21952420392SEric Paris return ret; 220c28f7e56SEric Paris } 221c28f7e56SEric Paris EXPORT_SYMBOL_GPL(__fsnotify_parent); 222c28f7e56SEric Paris 223fd657170SDan Carpenter static int send_to_group(struct inode *to_tell, 224e637835eSAl Viro __u32 mask, const void *data, 225613a807fSEric Paris int data_is, u32 cookie, 226e43e9c33SAl Viro const struct qstr *file_name, 2279385a84dSJan Kara struct fsnotify_iter_info *iter_info) 2287131485aSEric Paris { 229faa9560aSEric Paris struct fsnotify_group *group = NULL; 230007d1e83SAmir Goldstein __u32 test_mask = (mask & ALL_FSNOTIFY_EVENTS); 23192183a42SAmir Goldstein __u32 marks_mask = 0; 23292183a42SAmir Goldstein __u32 marks_ignored_mask = 0; 2333dca1a74SAmir Goldstein struct fsnotify_mark *mark; 2343dca1a74SAmir Goldstein int type; 235613a807fSEric Paris 2365b0457adSAmir Goldstein if (WARN_ON(!iter_info->report_mask)) 237faa9560aSEric Paris return 0; 2385ba08e2eSEric Paris 239ce8f76fbSEric Paris /* clear ignored on inode modification */ 240ce8f76fbSEric Paris if (mask & FS_MODIFY) { 2413dca1a74SAmir Goldstein fsnotify_foreach_obj_type(type) { 2423dca1a74SAmir Goldstein if (!fsnotify_iter_should_report_type(iter_info, type)) 2433dca1a74SAmir Goldstein continue; 2443dca1a74SAmir Goldstein mark = iter_info->marks[type]; 2453dca1a74SAmir Goldstein if (mark && 2463dca1a74SAmir Goldstein !(mark->flags & FSNOTIFY_MARK_FLAG_IGNORED_SURV_MODIFY)) 2473dca1a74SAmir Goldstein mark->ignored_mask = 0; 2483dca1a74SAmir Goldstein } 249ce8f76fbSEric Paris } 250613a807fSEric Paris 2513dca1a74SAmir Goldstein fsnotify_foreach_obj_type(type) { 2523dca1a74SAmir Goldstein if (!fsnotify_iter_should_report_type(iter_info, type)) 2533dca1a74SAmir Goldstein continue; 2543dca1a74SAmir Goldstein mark = iter_info->marks[type]; 2553dca1a74SAmir Goldstein /* does the object mark tell us to do something? */ 2563dca1a74SAmir Goldstein if (mark) { 2573dca1a74SAmir Goldstein group = mark->group; 2583dca1a74SAmir Goldstein marks_mask |= mark->mask; 2593dca1a74SAmir Goldstein marks_ignored_mask |= mark->ignored_mask; 2603dca1a74SAmir Goldstein } 261ce8f76fbSEric Paris } 262ce8f76fbSEric Paris 2633dca1a74SAmir Goldstein pr_debug("%s: group=%p to_tell=%p mask=%x marks_mask=%x marks_ignored_mask=%x" 2647053aee2SJan Kara " data=%p data_is=%d cookie=%d\n", 2653dca1a74SAmir Goldstein __func__, group, to_tell, mask, marks_mask, marks_ignored_mask, 2663dca1a74SAmir Goldstein data, data_is, cookie); 267faa9560aSEric Paris 26892183a42SAmir Goldstein if (!(test_mask & marks_mask & ~marks_ignored_mask)) 269613a807fSEric Paris return 0; 270613a807fSEric Paris 2715b0457adSAmir Goldstein return group->ops->handle_event(group, to_tell, mask, data, data_is, 2729385a84dSJan Kara file_name, cookie, iter_info); 2737131485aSEric Paris } 2747131485aSEric Paris 2753427ce71SMiklos Szeredi static struct fsnotify_mark *fsnotify_first_mark(struct fsnotify_mark_connector **connp) 2763427ce71SMiklos Szeredi { 2773427ce71SMiklos Szeredi struct fsnotify_mark_connector *conn; 2783427ce71SMiklos Szeredi struct hlist_node *node = NULL; 2793427ce71SMiklos Szeredi 2803427ce71SMiklos Szeredi conn = srcu_dereference(*connp, &fsnotify_mark_srcu); 2813427ce71SMiklos Szeredi if (conn) 2823427ce71SMiklos Szeredi node = srcu_dereference(conn->list.first, &fsnotify_mark_srcu); 2833427ce71SMiklos Szeredi 2843427ce71SMiklos Szeredi return hlist_entry_safe(node, struct fsnotify_mark, obj_list); 2853427ce71SMiklos Szeredi } 2863427ce71SMiklos Szeredi 2873427ce71SMiklos Szeredi static struct fsnotify_mark *fsnotify_next_mark(struct fsnotify_mark *mark) 2883427ce71SMiklos Szeredi { 2893427ce71SMiklos Szeredi struct hlist_node *node = NULL; 2903427ce71SMiklos Szeredi 2913427ce71SMiklos Szeredi if (mark) 2923427ce71SMiklos Szeredi node = srcu_dereference(mark->obj_list.next, 2933427ce71SMiklos Szeredi &fsnotify_mark_srcu); 2943427ce71SMiklos Szeredi 2953427ce71SMiklos Szeredi return hlist_entry_safe(node, struct fsnotify_mark, obj_list); 2963427ce71SMiklos Szeredi } 2973427ce71SMiklos Szeredi 298c28f7e56SEric Paris /* 299d9a6f30bSAmir Goldstein * iter_info is a multi head priority queue of marks. 300d9a6f30bSAmir Goldstein * Pick a subset of marks from queue heads, all with the 301d9a6f30bSAmir Goldstein * same group and set the report_mask for selected subset. 302d9a6f30bSAmir Goldstein * Returns the report_mask of the selected subset. 303d9a6f30bSAmir Goldstein */ 304d9a6f30bSAmir Goldstein static unsigned int fsnotify_iter_select_report_types( 305d9a6f30bSAmir Goldstein struct fsnotify_iter_info *iter_info) 306d9a6f30bSAmir Goldstein { 30747d9c7ccSAmir Goldstein struct fsnotify_group *max_prio_group = NULL; 30847d9c7ccSAmir Goldstein struct fsnotify_mark *mark; 30947d9c7ccSAmir Goldstein int type; 310d9a6f30bSAmir Goldstein 31147d9c7ccSAmir Goldstein /* Choose max prio group among groups of all queue heads */ 31247d9c7ccSAmir Goldstein fsnotify_foreach_obj_type(type) { 31347d9c7ccSAmir Goldstein mark = iter_info->marks[type]; 31447d9c7ccSAmir Goldstein if (mark && 31547d9c7ccSAmir Goldstein fsnotify_compare_groups(max_prio_group, mark->group) > 0) 31647d9c7ccSAmir Goldstein max_prio_group = mark->group; 317d9a6f30bSAmir Goldstein } 318d9a6f30bSAmir Goldstein 31947d9c7ccSAmir Goldstein if (!max_prio_group) 32047d9c7ccSAmir Goldstein return 0; 32147d9c7ccSAmir Goldstein 32247d9c7ccSAmir Goldstein /* Set the report mask for marks from same group as max prio group */ 323d9a6f30bSAmir Goldstein iter_info->report_mask = 0; 32447d9c7ccSAmir Goldstein fsnotify_foreach_obj_type(type) { 32547d9c7ccSAmir Goldstein mark = iter_info->marks[type]; 32647d9c7ccSAmir Goldstein if (mark && 32747d9c7ccSAmir Goldstein fsnotify_compare_groups(max_prio_group, mark->group) == 0) 32847d9c7ccSAmir Goldstein fsnotify_iter_set_report_type(iter_info, type); 32947d9c7ccSAmir Goldstein } 330d9a6f30bSAmir Goldstein 331d9a6f30bSAmir Goldstein return iter_info->report_mask; 332d9a6f30bSAmir Goldstein } 333d9a6f30bSAmir Goldstein 334d9a6f30bSAmir Goldstein /* 335d9a6f30bSAmir Goldstein * Pop from iter_info multi head queue, the marks that were iterated in the 336d9a6f30bSAmir Goldstein * current iteration step. 337d9a6f30bSAmir Goldstein */ 338d9a6f30bSAmir Goldstein static void fsnotify_iter_next(struct fsnotify_iter_info *iter_info) 339d9a6f30bSAmir Goldstein { 34047d9c7ccSAmir Goldstein int type; 341d9a6f30bSAmir Goldstein 34247d9c7ccSAmir Goldstein fsnotify_foreach_obj_type(type) { 34347d9c7ccSAmir Goldstein if (fsnotify_iter_should_report_type(iter_info, type)) 34447d9c7ccSAmir Goldstein iter_info->marks[type] = 34547d9c7ccSAmir Goldstein fsnotify_next_mark(iter_info->marks[type]); 34647d9c7ccSAmir Goldstein } 347d9a6f30bSAmir Goldstein } 348d9a6f30bSAmir Goldstein 349d9a6f30bSAmir Goldstein /* 35090586523SEric Paris * This is the main call to fsnotify. The VFS calls into hook specific functions 35190586523SEric Paris * in linux/fsnotify.h. Those functions then in turn call here. Here will call 35290586523SEric Paris * out to all of the registered fsnotify_group. Those groups can then use the 35390586523SEric Paris * notification event in whatever means they feel necessary. 35490586523SEric Paris */ 355e637835eSAl Viro int fsnotify(struct inode *to_tell, __u32 mask, const void *data, int data_is, 35625b229dfSAl Viro const struct qstr *file_name, u32 cookie) 35790586523SEric Paris { 3583427ce71SMiklos Szeredi struct fsnotify_iter_info iter_info = {}; 35945a9fb37SAmir Goldstein struct super_block *sb = to_tell->i_sb; 36060f7ed8cSAmir Goldstein struct mount *mnt = NULL; 36145a9fb37SAmir Goldstein __u32 mnt_or_sb_mask = sb->s_fsnotify_mask; 3629385a84dSJan Kara int ret = 0; 363007d1e83SAmir Goldstein __u32 test_mask = (mask & ALL_FSNOTIFY_EVENTS); 36490586523SEric Paris 36560f7ed8cSAmir Goldstein if (data_is == FSNOTIFY_EVENT_PATH) { 366e637835eSAl Viro mnt = real_mount(((const struct path *)data)->mnt); 36745a9fb37SAmir Goldstein mnt_or_sb_mask |= mnt->mnt_fsnotify_mask; 36860f7ed8cSAmir Goldstein } 369b469e7e4SAmir Goldstein /* An event "on child" is not intended for a mount/sb mark */ 370b469e7e4SAmir Goldstein if (mask & FS_EVENT_ON_CHILD) 371b469e7e4SAmir Goldstein mnt_or_sb_mask = 0; 372613a807fSEric Paris 373613a807fSEric Paris /* 3747c49b861SDave Hansen * Optimization: srcu_read_lock() has a memory barrier which can 3757c49b861SDave Hansen * be expensive. It protects walking the *_fsnotify_marks lists. 3767c49b861SDave Hansen * However, if we do not walk the lists, we do not have to do 3777c49b861SDave Hansen * SRCU because we have no references to any objects and do not 3787c49b861SDave Hansen * need SRCU to keep them "alive". 3797c49b861SDave Hansen */ 38045a9fb37SAmir Goldstein if (!to_tell->i_fsnotify_marks && !sb->s_fsnotify_marks && 38145a9fb37SAmir Goldstein (!mnt || !mnt->mnt_fsnotify_marks)) 3827c49b861SDave Hansen return 0; 3837c49b861SDave Hansen /* 384613a807fSEric Paris * if this is a modify event we may need to clear the ignored masks 38560f7ed8cSAmir Goldstein * otherwise return if neither the inode nor the vfsmount/sb care about 386613a807fSEric Paris * this type of event. 387613a807fSEric Paris */ 388613a807fSEric Paris if (!(mask & FS_MODIFY) && 38960f7ed8cSAmir Goldstein !(test_mask & (to_tell->i_fsnotify_mask | mnt_or_sb_mask))) 390613a807fSEric Paris return 0; 3913a9fb89fSEric Paris 3929385a84dSJan Kara iter_info.srcu_idx = srcu_read_lock(&fsnotify_mark_srcu); 3937131485aSEric Paris 39447d9c7ccSAmir Goldstein iter_info.marks[FSNOTIFY_OBJ_TYPE_INODE] = 3953427ce71SMiklos Szeredi fsnotify_first_mark(&to_tell->i_fsnotify_marks); 39645a9fb37SAmir Goldstein iter_info.marks[FSNOTIFY_OBJ_TYPE_SB] = 39745a9fb37SAmir Goldstein fsnotify_first_mark(&sb->s_fsnotify_marks); 3989bdda4e9SAmir Goldstein if (mnt) { 39947d9c7ccSAmir Goldstein iter_info.marks[FSNOTIFY_OBJ_TYPE_VFSMOUNT] = 4003427ce71SMiklos Szeredi fsnotify_first_mark(&mnt->mnt_fsnotify_marks); 4017131485aSEric Paris } 40275c1be48SEric Paris 4038edc6e16SJan Kara /* 40460f7ed8cSAmir Goldstein * We need to merge inode/vfsmount/sb mark lists so that e.g. inode mark 40560f7ed8cSAmir Goldstein * ignore masks are properly reflected for mount/sb mark notifications. 4068edc6e16SJan Kara * That's why this traversal is so complicated... 4078edc6e16SJan Kara */ 408d9a6f30bSAmir Goldstein while (fsnotify_iter_select_report_types(&iter_info)) { 4095b0457adSAmir Goldstein ret = send_to_group(to_tell, mask, data, data_is, cookie, 410e43e9c33SAl Viro file_name, &iter_info); 41184a5b68eSEric Paris 412ff8bcbd0SEric Paris if (ret && (mask & ALL_FSNOTIFY_PERM_EVENTS)) 413ff8bcbd0SEric Paris goto out; 414ff8bcbd0SEric Paris 415d9a6f30bSAmir Goldstein fsnotify_iter_next(&iter_info); 4167131485aSEric Paris } 417ff8bcbd0SEric Paris ret = 0; 418ff8bcbd0SEric Paris out: 4199385a84dSJan Kara srcu_read_unlock(&fsnotify_mark_srcu, iter_info.srcu_idx); 420c4ec54b4SEric Paris 42198b5c10dSJean-Christophe Dubois return ret; 42290586523SEric Paris } 42390586523SEric Paris EXPORT_SYMBOL_GPL(fsnotify); 42490586523SEric Paris 4259dd813c1SJan Kara extern struct kmem_cache *fsnotify_mark_connector_cachep; 4269dd813c1SJan Kara 42790586523SEric Paris static __init int fsnotify_init(void) 42890586523SEric Paris { 42975c1be48SEric Paris int ret; 43075c1be48SEric Paris 43166917a31SMatthew Bobrowski BUILD_BUG_ON(HWEIGHT32(ALL_FSNOTIFY_BITS) != 25); 43220dee624SEric Paris 43375c1be48SEric Paris ret = init_srcu_struct(&fsnotify_mark_srcu); 43475c1be48SEric Paris if (ret) 43575c1be48SEric Paris panic("initializing fsnotify_mark_srcu"); 43675c1be48SEric Paris 4379dd813c1SJan Kara fsnotify_mark_connector_cachep = KMEM_CACHE(fsnotify_mark_connector, 4389dd813c1SJan Kara SLAB_PANIC); 4399dd813c1SJan Kara 44075c1be48SEric Paris return 0; 44190586523SEric Paris } 44275c1be48SEric Paris core_initcall(fsnotify_init); 443