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authorNick Piggin <npiggin@kernel.dk>2011-01-07 17:49:23 +1100
committerNick Piggin <npiggin@kernel.dk>2011-01-07 17:50:18 +1100
commitfe15ce446beb3a33583af81ffe6c9d01a75314ed (patch)
treebc8af66b6dd2d0f21a2a3f48a19975ae2cdbae4e
parent5eef7fa905c814826f518aca2d414ca77508ce30 (diff)
fs: change d_delete semantics
Change d_delete from a dentry deletion notification to a dentry caching advise, more like ->drop_inode. Require it to be constant and idempotent, and not take d_lock. This is how all existing filesystems use the callback anyway. This makes fine grained dentry locking of dput and dentry lru scanning much simpler. Signed-off-by: Nick Piggin <npiggin@kernel.dk>
-rw-r--r--Documentation/filesystems/porting8
-rw-r--r--Documentation/filesystems/vfs.txt27
-rw-r--r--arch/ia64/kernel/perfmon.c2
-rw-r--r--drivers/staging/smbfs/dir.c4
-rw-r--r--fs/9p/vfs_dentry.c4
-rw-r--r--fs/afs/dir.c4
-rw-r--r--fs/btrfs/inode.c2
-rw-r--r--fs/coda/dir.c4
-rw-r--r--fs/configfs/dir.c2
-rw-r--r--fs/dcache.c2
-rw-r--r--fs/gfs2/dentry.c2
-rw-r--r--fs/hostfs/hostfs_kern.c2
-rw-r--r--fs/libfs.c2
-rw-r--r--fs/ncpfs/dir.c4
-rw-r--r--fs/nfs/dir.c2
-rw-r--r--fs/proc/base.c2
-rw-r--r--fs/proc/generic.c2
-rw-r--r--fs/proc/proc_sysctl.c2
-rw-r--r--fs/sysfs/dir.c2
-rw-r--r--include/linux/dcache.h6
-rw-r--r--kernel/cgroup.c2
-rw-r--r--net/sunrpc/rpc_pipe.c2
22 files changed, 47 insertions, 42 deletions
diff --git a/Documentation/filesystems/porting b/Documentation/filesystems/porting
index b12c8953868..9e71c9ad310 100644
--- a/Documentation/filesystems/porting
+++ b/Documentation/filesystems/porting
@@ -318,3 +318,11 @@ if it's zero is not *and* *never* *had* *been* enough. Final unlink() and iput(
may happen while the inode is in the middle of ->write_inode(); e.g. if you blindly
free the on-disk inode, you may end up doing that while ->write_inode() is writing
to it.
+
+---
+[mandatory]
+
+ .d_delete() now only advises the dcache as to whether or not to cache
+unreferenced dentries, and is now only called when the dentry refcount goes to
+0. Even on 0 refcount transition, it must be able to tolerate being called 0,
+1, or more times (eg. constant, idempotent).
diff --git a/Documentation/filesystems/vfs.txt b/Documentation/filesystems/vfs.txt
index 20899e095e7..95c0a93f056 100644
--- a/Documentation/filesystems/vfs.txt
+++ b/Documentation/filesystems/vfs.txt
@@ -847,9 +847,9 @@ defined:
struct dentry_operations {
int (*d_revalidate)(struct dentry *, struct nameidata *);
- int (*d_hash) (struct dentry *, struct qstr *);
- int (*d_compare) (struct dentry *, struct qstr *, struct qstr *);
- int (*d_delete)(struct dentry *);
+ int (*d_hash)(struct dentry *, struct qstr *);
+ int (*d_compare)(struct dentry *, struct qstr *, struct qstr *);
+ int (*d_delete)(const struct dentry *);
void (*d_release)(struct dentry *);
void (*d_iput)(struct dentry *, struct inode *);
char *(*d_dname)(struct dentry *, char *, int);
@@ -864,9 +864,11 @@ struct dentry_operations {
d_compare: called when a dentry should be compared with another
- d_delete: called when the last reference to a dentry is
- deleted. This means no-one is using the dentry, however it is
- still valid and in the dcache
+ d_delete: called when the last reference to a dentry is dropped and the
+ dcache is deciding whether or not to cache it. Return 1 to delete
+ immediately, or 0 to cache the dentry. Default is NULL which means to
+ always cache a reachable dentry. d_delete must be constant and
+ idempotent.
d_release: called when a dentry is really deallocated
@@ -910,14 +912,11 @@ manipulate dentries:
the usage count)
dput: close a handle for a dentry (decrements the usage count). If
- the usage count drops to 0, the "d_delete" method is called
- and the dentry is placed on the unused list if the dentry is
- still in its parents hash list. Putting the dentry on the
- unused list just means that if the system needs some RAM, it
- goes through the unused list of dentries and deallocates them.
- If the dentry has already been unhashed and the usage count
- drops to 0, in this case the dentry is deallocated after the
- "d_delete" method is called
+ the usage count drops to 0, and the dentry is still in its
+ parent's hash, the "d_delete" method is called to check whether
+ it should be cached. If it should not be cached, or if the dentry
+ is not hashed, it is deleted. Otherwise cached dentries are put
+ into an LRU list to be reclaimed on memory shortage.
d_drop: this unhashes a dentry from its parents hash list. A
subsequent call to dput() will deallocate the dentry if its
diff --git a/arch/ia64/kernel/perfmon.c b/arch/ia64/kernel/perfmon.c
index 39e534f5a3b..d39d8a53b57 100644
--- a/arch/ia64/kernel/perfmon.c
+++ b/arch/ia64/kernel/perfmon.c
@@ -2185,7 +2185,7 @@ static const struct file_operations pfm_file_ops = {
};
static int
-pfmfs_delete_dentry(struct dentry *dentry)
+pfmfs_delete_dentry(const struct dentry *dentry)
{
return 1;
}
diff --git a/drivers/staging/smbfs/dir.c b/drivers/staging/smbfs/dir.c
index f088ea2f6ac..2270d4822c2 100644
--- a/drivers/staging/smbfs/dir.c
+++ b/drivers/staging/smbfs/dir.c
@@ -276,7 +276,7 @@ smb_dir_open(struct inode *dir, struct file *file)
static int smb_lookup_validate(struct dentry *, struct nameidata *);
static int smb_hash_dentry(struct dentry *, struct qstr *);
static int smb_compare_dentry(struct dentry *, struct qstr *, struct qstr *);
-static int smb_delete_dentry(struct dentry *);
+static int smb_delete_dentry(const struct dentry *);
static const struct dentry_operations smbfs_dentry_operations =
{
@@ -367,7 +367,7 @@ out:
* We use this to unhash dentries with bad inodes.
*/
static int
-smb_delete_dentry(struct dentry * dentry)
+smb_delete_dentry(const struct dentry *dentry)
{
if (dentry->d_inode) {
if (is_bad_inode(dentry->d_inode)) {
diff --git a/fs/9p/vfs_dentry.c b/fs/9p/vfs_dentry.c
index cbf4e50f393..466d2a4fc5c 100644
--- a/fs/9p/vfs_dentry.c
+++ b/fs/9p/vfs_dentry.c
@@ -51,7 +51,7 @@
*
*/
-static int v9fs_dentry_delete(struct dentry *dentry)
+static int v9fs_dentry_delete(const struct dentry *dentry)
{
P9_DPRINTK(P9_DEBUG_VFS, " dentry: %s (%p)\n", dentry->d_name.name,
dentry);
@@ -68,7 +68,7 @@ static int v9fs_dentry_delete(struct dentry *dentry)
*
*/
-static int v9fs_cached_dentry_delete(struct dentry *dentry)
+static int v9fs_cached_dentry_delete(const struct dentry *dentry)
{
struct inode *inode = dentry->d_inode;
P9_DPRINTK(P9_DEBUG_VFS, " dentry: %s (%p)\n", dentry->d_name.name,
diff --git a/fs/afs/dir.c b/fs/afs/dir.c
index 5439e1bc9a8..2c18cde2700 100644
--- a/fs/afs/dir.c
+++ b/fs/afs/dir.c
@@ -23,7 +23,7 @@ static struct dentry *afs_lookup(struct inode *dir, struct dentry *dentry,
static int afs_dir_open(struct inode *inode, struct file *file);
static int afs_readdir(struct file *file, void *dirent, filldir_t filldir);
static int afs_d_revalidate(struct dentry *dentry, struct nameidata *nd);
-static int afs_d_delete(struct dentry *dentry);
+static int afs_d_delete(const struct dentry *dentry);
static void afs_d_release(struct dentry *dentry);
static int afs_lookup_filldir(void *_cookie, const char *name, int nlen,
loff_t fpos, u64 ino, unsigned dtype);
@@ -730,7 +730,7 @@ out_bad:
* - called from dput() when d_count is going to 0.
* - return 1 to request dentry be unhashed, 0 otherwise
*/
-static int afs_d_delete(struct dentry *dentry)
+static int afs_d_delete(const struct dentry *dentry)
{
_enter("%s", dentry->d_name.name);
diff --git a/fs/btrfs/inode.c b/fs/btrfs/inode.c
index 72f31ecb5c9..7ce9f893278 100644
--- a/fs/btrfs/inode.c
+++ b/fs/btrfs/inode.c
@@ -4127,7 +4127,7 @@ struct inode *btrfs_lookup_dentry(struct inode *dir, struct dentry *dentry)
return inode;
}
-static int btrfs_dentry_delete(struct dentry *dentry)
+static int btrfs_dentry_delete(const struct dentry *dentry)
{
struct btrfs_root *root;
diff --git a/fs/coda/dir.c b/fs/coda/dir.c
index 5d8b3553960..4cce3b07d9d 100644
--- a/fs/coda/dir.c
+++ b/fs/coda/dir.c
@@ -47,7 +47,7 @@ static int coda_readdir(struct file *file, void *buf, filldir_t filldir);
/* dentry ops */
static int coda_dentry_revalidate(struct dentry *de, struct nameidata *nd);
-static int coda_dentry_delete(struct dentry *);
+static int coda_dentry_delete(const struct dentry *);
/* support routines */
static int coda_venus_readdir(struct file *coda_file, void *buf,
@@ -577,7 +577,7 @@ out:
* This is the callback from dput() when d_count is going to 0.
* We use this to unhash dentries with bad inodes.
*/
-static int coda_dentry_delete(struct dentry * dentry)
+static int coda_dentry_delete(const struct dentry * dentry)
{
int flags;
diff --git a/fs/configfs/dir.c b/fs/configfs/dir.c
index 57870696941..20024a9ef5a 100644
--- a/fs/configfs/dir.c
+++ b/fs/configfs/dir.c
@@ -67,7 +67,7 @@ static void configfs_d_iput(struct dentry * dentry,
* We _must_ delete our dentries on last dput, as the chain-to-parent
* behavior is required to clear the parents of default_groups.
*/
-static int configfs_d_delete(struct dentry *dentry)
+static int configfs_d_delete(const struct dentry *dentry)
{
return 1;
}
diff --git a/fs/dcache.c b/fs/dcache.c
index b2cb2662ca0..6ee6bc40cb6 100644
--- a/fs/dcache.c
+++ b/fs/dcache.c
@@ -453,8 +453,6 @@ static void prune_one_dentry(struct dentry * dentry)
if (!atomic_dec_and_lock(&dentry->d_count, &dentry->d_lock))
return;
- if (dentry->d_op && dentry->d_op->d_delete)
- dentry->d_op->d_delete(dentry);
dentry_lru_del(dentry);
__d_drop(dentry);
dentry = d_kill(dentry);
diff --git a/fs/gfs2/dentry.c b/fs/gfs2/dentry.c
index 6798755b385..e80fea2f65f 100644
--- a/fs/gfs2/dentry.c
+++ b/fs/gfs2/dentry.c
@@ -106,7 +106,7 @@ static int gfs2_dhash(struct dentry *dentry, struct qstr *str)
return 0;
}
-static int gfs2_dentry_delete(struct dentry *dentry)
+static int gfs2_dentry_delete(const struct dentry *dentry)
{
struct gfs2_inode *ginode;
diff --git a/fs/hostfs/hostfs_kern.c b/fs/hostfs/hostfs_kern.c
index 2c0f148a49e..cfe8bc7de51 100644
--- a/fs/hostfs/hostfs_kern.c
+++ b/fs/hostfs/hostfs_kern.c
@@ -32,7 +32,7 @@ static inline struct hostfs_inode_info *HOSTFS_I(struct inode *inode)
#define FILE_HOSTFS_I(file) HOSTFS_I((file)->f_path.dentry->d_inode)
-static int hostfs_d_delete(struct dentry *dentry)
+static int hostfs_d_delete(const struct dentry *dentry)
{
return 1;
}
diff --git a/fs/libfs.c b/fs/libfs.c
index a3accdf528a..b9d25d83e22 100644
--- a/fs/libfs.c
+++ b/fs/libfs.c
@@ -37,7 +37,7 @@ int simple_statfs(struct dentry *dentry, struct kstatfs *buf)
* Retaining negative dentries for an in-memory filesystem just wastes
* memory and lookup time: arrange for them to be deleted immediately.
*/
-static int simple_delete_dentry(struct dentry *dentry)
+static int simple_delete_dentry(const struct dentry *dentry)
{
return 1;
}
diff --git a/fs/ncpfs/dir.c b/fs/ncpfs/dir.c
index f22b12e7d33..d6e6453881c 100644
--- a/fs/ncpfs/dir.c
+++ b/fs/ncpfs/dir.c
@@ -76,7 +76,7 @@ const struct inode_operations ncp_dir_inode_operations =
static int ncp_lookup_validate(struct dentry *, struct nameidata *);
static int ncp_hash_dentry(struct dentry *, struct qstr *);
static int ncp_compare_dentry (struct dentry *, struct qstr *, struct qstr *);
-static int ncp_delete_dentry(struct dentry *);
+static int ncp_delete_dentry(const struct dentry *);
static const struct dentry_operations ncp_dentry_operations =
{
@@ -162,7 +162,7 @@ ncp_compare_dentry(struct dentry *dentry, struct qstr *a, struct qstr *b)
* Closing files can be safely postponed until iput() - it's done there anyway.
*/
static int
-ncp_delete_dentry(struct dentry * dentry)
+ncp_delete_dentry(const struct dentry * dentry)
{
struct inode *inode = dentry->d_inode;
diff --git a/fs/nfs/dir.c b/fs/nfs/dir.c
index 996dd8989a9..9184c7c80f7 100644
--- a/fs/nfs/dir.c
+++ b/fs/nfs/dir.c
@@ -1117,7 +1117,7 @@ out_error:
/*
* This is called from dput() when d_count is going to 0.
*/
-static int nfs_dentry_delete(struct dentry *dentry)
+static int nfs_dentry_delete(const struct dentry *dentry)
{
dfprintk(VFS, "NFS: dentry_delete(%s/%s, %x)\n",
dentry->d_parent->d_name.name, dentry->d_name.name,
diff --git a/fs/proc/base.c b/fs/proc/base.c
index 182845147fe..d932fdb6a24 100644
--- a/fs/proc/base.c
+++ b/fs/proc/base.c
@@ -1744,7 +1744,7 @@ static int pid_revalidate(struct dentry *dentry, struct nameidata *nd)
return 0;
}
-static int pid_delete_dentry(struct dentry * dentry)
+static int pid_delete_dentry(const struct dentry * dentry)
{
/* Is the task we represent dead?
* If so, then don't put the dentry on the lru list,
diff --git a/fs/proc/generic.c b/fs/proc/generic.c
index dd29f033766..1d607be36d9 100644
--- a/fs/proc/generic.c
+++ b/fs/proc/generic.c
@@ -400,7 +400,7 @@ static const struct inode_operations proc_link_inode_operations = {
* smarter: we could keep a "volatile" flag in the
* inode to indicate which ones to keep.
*/
-static int proc_delete_dentry(struct dentry * dentry)
+static int proc_delete_dentry(const struct dentry * dentry)
{
return 1;
}
diff --git a/fs/proc/proc_sysctl.c b/fs/proc/proc_sysctl.c
index b652cb00906..a256d770ea1 100644
--- a/fs/proc/proc_sysctl.c
+++ b/fs/proc/proc_sysctl.c
@@ -392,7 +392,7 @@ static int proc_sys_revalidate(struct dentry *dentry, struct nameidata *nd)
return !PROC_I(dentry->d_inode)->sysctl->unregistering;
}
-static int proc_sys_delete(struct dentry *dentry)
+static int proc_sys_delete(const struct dentry *dentry)
{
return !!PROC_I(dentry->d_inode)->sysctl->unregistering;
}
diff --git a/fs/sysfs/dir.c b/fs/sysfs/dir.c
index 7e54bac8c4b..27e1102e303 100644
--- a/fs/sysfs/dir.c
+++ b/fs/sysfs/dir.c
@@ -231,7 +231,7 @@ void release_sysfs_dirent(struct sysfs_dirent * sd)
goto repeat;
}
-static int sysfs_dentry_delete(struct dentry *dentry)
+static int sysfs_dentry_delete(const struct dentry *dentry)
{
struct sysfs_dirent *sd = dentry->d_fsdata;
return !!(sd->s_flags & SYSFS_FLAG_REMOVED);
diff --git a/include/linux/dcache.h b/include/linux/dcache.h
index fff975576b5..cbfc9567e4e 100644
--- a/include/linux/dcache.h
+++ b/include/linux/dcache.h
@@ -133,9 +133,9 @@ enum dentry_d_lock_class
struct dentry_operations {
int (*d_revalidate)(struct dentry *, struct nameidata *);
- int (*d_hash) (struct dentry *, struct qstr *);
- int (*d_compare) (struct dentry *, struct qstr *, struct qstr *);
- int (*d_delete)(struct dentry *);
+ int (*d_hash)(struct dentry *, struct qstr *);
+ int (*d_compare)(struct dentry *, struct qstr *, struct qstr *);
+ int (*d_delete)(const struct dentry *);
void (*d_release)(struct dentry *);
void (*d_iput)(struct dentry *, struct inode *);
char *(*d_dname)(struct dentry *, char *, int);
diff --git a/kernel/cgroup.c b/kernel/cgroup.c
index 163c890f436..746055b214d 100644
--- a/kernel/cgroup.c
+++ b/kernel/cgroup.c
@@ -2198,7 +2198,7 @@ static inline struct cftype *__file_cft(struct file *file)
return __d_cft(file->f_dentry);
}
-static int cgroup_delete_dentry(struct dentry *dentry)
+static int cgroup_delete_dentry(const struct dentry *dentry)
{
return 1;
}
diff --git a/net/sunrpc/rpc_pipe.c b/net/sunrpc/rpc_pipe.c
index 10a17a37ec4..a0dc1a86fce 100644
--- a/net/sunrpc/rpc_pipe.c
+++ b/net/sunrpc/rpc_pipe.c
@@ -430,7 +430,7 @@ void rpc_put_mount(void)
}
EXPORT_SYMBOL_GPL(rpc_put_mount);
-static int rpc_delete_dentry(struct dentry *dentry)
+static int rpc_delete_dentry(const struct dentry *dentry)
{
return 1;
}