From 407669f2c9fe9f32aeb39f715d748fe456718aac Mon Sep 17 00:00:00 2001 From: Al Viro Date: Fri, 7 Jul 2017 14:51:19 -0400 Subject: dentry name snapshots 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 --- include/linux/dcache.h | 6 ++++++ include/linux/fsnotify.h | 31 ------------------------------- 2 files changed, 6 insertions(+), 31 deletions(-) (limited to 'include/linux') diff --git a/include/linux/dcache.h b/include/linux/dcache.h index 8d7151eb6ceb..d516847e0fae 100644 --- a/include/linux/dcache.h +++ b/include/linux/dcache.h @@ -615,5 +615,11 @@ static inline struct inode *d_real_inode(struct dentry *dentry) return d_backing_inode(d_real(dentry)); } +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 */ diff --git a/include/linux/fsnotify.h b/include/linux/fsnotify.h index 7ee1774edee5..a7789559078b 100644 --- a/include/linux/fsnotify.h +++ b/include/linux/fsnotify.h @@ -310,35 +310,4 @@ static inline void fsnotify_change(struct dentry *dentry, unsigned int ia_valid) } } -#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 */ -- cgit v1.2.3