From: Greg Kroah-Hartman Date: Thu, 3 Aug 2017 23:03:46 +0000 (-0700) Subject: 3.18-stable patches X-Git-Tag: v4.12.5~26 X-Git-Url: http://git.ipfire.org/?a=commitdiff_plain;h=f8bc639b8417ef6241dac77c05dcb201d5494911;p=thirdparty%2Fkernel%2Fstable-queue.git 3.18-stable patches added patches: dentry-name-snapshots.patch --- diff --git a/queue-3.18/dentry-name-snapshots.patch b/queue-3.18/dentry-name-snapshots.patch new file mode 100644 index 00000000000..17dcd59bf69 --- /dev/null +++ b/queue-3.18/dentry-name-snapshots.patch @@ -0,0 +1,229 @@ +From 49d31c2f389acfe83417083e1208422b4091cd9e Mon Sep 17 00:00:00 2001 +From: Al Viro +Date: Fri, 7 Jul 2017 14:51:19 -0400 +Subject: dentry name snapshots + +From: Al Viro + +commit 49d31c2f389acfe83417083e1208422b4091cd9e upstream. + +take_dentry_name_snapshot() takes a safe snapshot of dentry name; +if the name is a short one, it gets copied into caller-supplied +structure, otherwise an extra reference to external name is grabbed +(those are never modified). In either case the pointer to stable +string is stored into the same structure. + +dentry must be held by the caller of take_dentry_name_snapshot(), +but may be freely dropped afterwards - the snapshot will stay +until destroyed by release_dentry_name_snapshot(). + +Intended use: + struct name_snapshot s; + + take_dentry_name_snapshot(&s, dentry); + ... + access s.name + ... + release_dentry_name_snapshot(&s); + +Replaces fsnotify_oldname_...(), gets used in fsnotify to obtain the name +to pass down with event. + +Signed-off-by: Al Viro +Signed-off-by: Greg Kroah-Hartman + +--- + fs/dcache.c | 27 +++++++++++++++++++++++++++ + fs/debugfs/inode.c | 10 +++++----- + fs/namei.c | 8 ++++---- + fs/notify/fsnotify.c | 8 ++++++-- + include/linux/dcache.h | 7 +++++++ + include/linux/fsnotify.h | 31 ------------------------------- + 6 files changed, 49 insertions(+), 42 deletions(-) + +--- a/fs/dcache.c ++++ b/fs/dcache.c +@@ -3549,3 +3549,30 @@ void __init vfs_caches_init(unsigned lon + bdev_cache_init(); + chrdev_init(); + } ++ ++void take_dentry_name_snapshot(struct name_snapshot *name, struct dentry *dentry) ++{ ++ spin_lock(&dentry->d_lock); ++ if (unlikely(dname_external(dentry))) { ++ struct external_name *p = external_name(dentry); ++ atomic_inc(&p->u.count); ++ spin_unlock(&dentry->d_lock); ++ name->name = p->name; ++ } else { ++ memcpy(name->inline_name, dentry->d_iname, DNAME_INLINE_LEN); ++ spin_unlock(&dentry->d_lock); ++ name->name = name->inline_name; ++ } ++} ++EXPORT_SYMBOL(take_dentry_name_snapshot); ++ ++void release_dentry_name_snapshot(struct name_snapshot *name) ++{ ++ if (unlikely(name->name != name->inline_name)) { ++ struct external_name *p; ++ p = container_of(name->name, struct external_name, name[0]); ++ if (unlikely(atomic_dec_and_test(&p->u.count))) ++ kfree_rcu(p, u.head); ++ } ++} ++EXPORT_SYMBOL(release_dentry_name_snapshot); +--- a/fs/debugfs/inode.c ++++ b/fs/debugfs/inode.c +@@ -620,7 +620,7 @@ struct dentry *debugfs_rename(struct den + { + int error; + struct dentry *dentry = NULL, *trap; +- const char *old_name; ++ struct name_snapshot old_name; + + trap = lock_rename(new_dir, old_dir); + /* Source or destination directories don't exist? */ +@@ -635,19 +635,19 @@ struct dentry *debugfs_rename(struct den + if (IS_ERR(dentry) || dentry == trap || dentry->d_inode) + goto exit; + +- old_name = fsnotify_oldname_init(old_dentry->d_name.name); ++ take_dentry_name_snapshot(&old_name, old_dentry); + + error = simple_rename(old_dir->d_inode, old_dentry, new_dir->d_inode, + dentry); + if (error) { +- fsnotify_oldname_free(old_name); ++ release_dentry_name_snapshot(&old_name); + goto exit; + } + d_move(old_dentry, dentry); +- fsnotify_move(old_dir->d_inode, new_dir->d_inode, old_name, ++ fsnotify_move(d_inode(old_dir), d_inode(new_dir), old_name.name, + S_ISDIR(old_dentry->d_inode->i_mode), + NULL, old_dentry); +- fsnotify_oldname_free(old_name); ++ release_dentry_name_snapshot(&old_name); + unlock_rename(new_dir, old_dir); + dput(dentry); + return old_dentry; +--- a/fs/namei.c ++++ b/fs/namei.c +@@ -4088,11 +4088,11 @@ int vfs_rename(struct inode *old_dir, st + { + int error; + bool is_dir = d_is_dir(old_dentry); +- const unsigned char *old_name; + struct inode *source = old_dentry->d_inode; + struct inode *target = new_dentry->d_inode; + bool new_is_dir = false; + unsigned max_links = new_dir->i_sb->s_max_links; ++ struct name_snapshot old_name; + + if (source == target) + return 0; +@@ -4142,7 +4142,7 @@ int vfs_rename(struct inode *old_dir, st + if (error) + return error; + +- old_name = fsnotify_oldname_init(old_dentry->d_name.name); ++ take_dentry_name_snapshot(&old_name, old_dentry); + dget(new_dentry); + if (!is_dir || (flags & RENAME_EXCHANGE)) + lock_two_nondirectories(source, target); +@@ -4203,14 +4203,14 @@ out: + mutex_unlock(&target->i_mutex); + dput(new_dentry); + if (!error) { +- fsnotify_move(old_dir, new_dir, old_name, is_dir, ++ fsnotify_move(old_dir, new_dir, old_name.name, is_dir, + !(flags & RENAME_EXCHANGE) ? target : NULL, old_dentry); + if (flags & RENAME_EXCHANGE) { + fsnotify_move(new_dir, old_dir, old_dentry->d_name.name, + new_is_dir, NULL, new_dentry); + } + } +- fsnotify_oldname_free(old_name); ++ release_dentry_name_snapshot(&old_name); + + return error; + } +--- a/fs/notify/fsnotify.c ++++ b/fs/notify/fsnotify.c +@@ -105,16 +105,20 @@ int __fsnotify_parent(struct path *path, + if (unlikely(!fsnotify_inode_watches_children(p_inode))) + __fsnotify_update_child_dentry_flags(p_inode); + else if (p_inode->i_fsnotify_mask & mask) { ++ struct name_snapshot name; ++ + /* we are notifying a parent so come up with the new mask which + * specifies these are events which came from a child. */ + mask |= FS_EVENT_ON_CHILD; + ++ take_dentry_name_snapshot(&name, dentry); + if (path) + ret = fsnotify(p_inode, mask, path, FSNOTIFY_EVENT_PATH, +- dentry->d_name.name, 0); ++ name.name, 0); + else + ret = fsnotify(p_inode, mask, dentry->d_inode, FSNOTIFY_EVENT_INODE, +- dentry->d_name.name, 0); ++ name.name, 0); ++ release_dentry_name_snapshot(&name); + } + + dput(parent); +--- a/include/linux/dcache.h ++++ b/include/linux/dcache.h +@@ -527,4 +527,11 @@ static inline struct dentry *d_backing_d + return upper; + } + ++struct name_snapshot { ++ const char *name; ++ char inline_name[DNAME_INLINE_LEN]; ++}; ++void take_dentry_name_snapshot(struct name_snapshot *, struct dentry *); ++void release_dentry_name_snapshot(struct name_snapshot *); ++ + #endif /* __LINUX_DCACHE_H */ +--- a/include/linux/fsnotify.h ++++ b/include/linux/fsnotify.h +@@ -310,35 +310,4 @@ static inline void fsnotify_change(struc + } + } + +-#if defined(CONFIG_FSNOTIFY) /* notify helpers */ +- +-/* +- * fsnotify_oldname_init - save off the old filename before we change it +- */ +-static inline const unsigned char *fsnotify_oldname_init(const unsigned char *name) +-{ +- return kstrdup(name, GFP_KERNEL); +-} +- +-/* +- * fsnotify_oldname_free - free the name we got from fsnotify_oldname_init +- */ +-static inline void fsnotify_oldname_free(const unsigned char *old_name) +-{ +- kfree(old_name); +-} +- +-#else /* CONFIG_FSNOTIFY */ +- +-static inline const char *fsnotify_oldname_init(const unsigned char *name) +-{ +- return NULL; +-} +- +-static inline void fsnotify_oldname_free(const unsigned char *old_name) +-{ +-} +- +-#endif /* CONFIG_FSNOTIFY */ +- + #endif /* _LINUX_FS_NOTIFY_H */ diff --git a/queue-3.18/series b/queue-3.18/series index a1595501a42..075f5374eeb 100644 --- a/queue-3.18/series +++ b/queue-3.18/series @@ -29,3 +29,4 @@ net-sctp-fix-race-for-one-to-many-sockets-in-sendmsg-s-auto-associate.patch sh_eth-fix-ethtool-operation-crash-when-net-device-is-down.patch net-sched-fix-soft-lockup-in-tc_classify.patch ipmi-watchdog-fix-watchdog-timeout-set-on-reboot.patch +dentry-name-snapshots.patch