From b1e6a015a580ad145689ad1d6b4aa0e03e6c868b Mon Sep 17 00:00:00 2001 From: Nick Piggin Date: Fri, 7 Jan 2011 17:49:28 +1100 Subject: fs: change d_hash for rcu-walk Change d_hash so it may be called from lock-free RCU lookups. See similar patch for d_compare for details. For in-tree filesystems, this is just a mechanical change. Signed-off-by: Nick Piggin --- Documentation/filesystems/Locking | 5 +++-- Documentation/filesystems/porting | 7 +++++++ Documentation/filesystems/vfs.txt | 8 ++++++-- 3 files changed, 16 insertions(+), 4 deletions(-) (limited to 'Documentation') diff --git a/Documentation/filesystems/Locking b/Documentation/filesystems/Locking index 9a76f8d8bf9..a15ee207b44 100644 --- a/Documentation/filesystems/Locking +++ b/Documentation/filesystems/Locking @@ -10,7 +10,8 @@ be able to use diff(1). --------------------------- dentry_operations -------------------------- prototypes: int (*d_revalidate)(struct dentry *, int); - int (*d_hash) (struct dentry *, struct qstr *); + int (*d_hash)(const struct dentry *, const struct inode *, + struct qstr *); int (*d_compare)(const struct dentry *, const struct inode *, const struct dentry *, const struct inode *, unsigned int, const char *, const struct qstr *); @@ -22,7 +23,7 @@ prototypes: locking rules: dcache_lock rename_lock ->d_lock may block d_revalidate: no no no yes -d_hash no no no yes +d_hash no no no no d_compare: no yes no no d_delete: yes no yes no d_release: no no no yes diff --git a/Documentation/filesystems/porting b/Documentation/filesystems/porting index d44511e2082..9fd31940a8e 100644 --- a/Documentation/filesystems/porting +++ b/Documentation/filesystems/porting @@ -333,3 +333,10 @@ unreferenced dentries, and is now only called when the dentry refcount goes to .d_compare() calling convention and locking rules are significantly changed. Read updated documentation in Documentation/filesystems/vfs.txt (and look at examples of other filesystems) for guidance. + +--- +[mandatory] + + .d_hash() calling convention and locking rules are significantly +changed. Read updated documentation in Documentation/filesystems/vfs.txt (and +look at examples of other filesystems) for guidance. diff --git a/Documentation/filesystems/vfs.txt b/Documentation/filesystems/vfs.txt index 250681b8c7c..69b10ff5ec8 100644 --- a/Documentation/filesystems/vfs.txt +++ b/Documentation/filesystems/vfs.txt @@ -847,7 +847,8 @@ defined: struct dentry_operations { int (*d_revalidate)(struct dentry *, struct nameidata *); - int (*d_hash)(struct dentry *, struct qstr *); + int (*d_hash)(const struct dentry *, const struct inode *, + struct qstr *); int (*d_compare)(const struct dentry *, const struct inode *, const struct dentry *, const struct inode *, unsigned int, const char *, const struct qstr *); @@ -864,7 +865,10 @@ struct dentry_operations { d_hash: called when the VFS adds a dentry to the hash table. The first dentry passed to d_hash is the parent directory that the name is - to be hashed into. + to be hashed into. The inode is the dentry's inode. + + Same locking and synchronisation rules as d_compare regarding + what is safe to dereference etc. d_compare: called to compare a dentry name with a given name. The first dentry is the parent of the dentry to be compared, the second is -- cgit v1.2.3-18-g5258