From 285b102d3b745f3c2c110c9c327741d87e64aacc Mon Sep 17 00:00:00 2001 From: Miklos Szeredi Date: Tue, 28 Jun 2016 11:47:32 +0200 Subject: [PATCH] vfs: new d_init method Allow filesystem to initialize dentry at allocation time. Signed-off-by: Miklos Szeredi Signed-off-by: Al Viro --- Documentation/filesystems/Locking | 2 ++ Documentation/filesystems/vfs.txt | 3 +++ fs/dcache.c | 11 +++++++++++ include/linux/dcache.h | 1 + 4 files changed, 17 insertions(+) diff --git a/Documentation/filesystems/Locking b/Documentation/filesystems/Locking index a38da93865c2..794adbe55399 100644 --- a/Documentation/filesystems/Locking +++ b/Documentation/filesystems/Locking @@ -15,6 +15,7 @@ prototypes: int (*d_compare)(const struct dentry *, const struct dentry *, unsigned int, const char *, const struct qstr *); int (*d_delete)(struct dentry *); + int (*d_init)(struct dentry *); void (*d_release)(struct dentry *); void (*d_iput)(struct dentry *, struct inode *); char *(*d_dname)((struct dentry *dentry, char *buffer, int buflen); @@ -30,6 +31,7 @@ d_weak_revalidate:no no yes no d_hash no no no maybe d_compare: yes no no maybe d_delete: no yes no no +d_init: no no yes no d_release: no no yes no d_prune: no yes no no d_iput: no no yes no diff --git a/Documentation/filesystems/vfs.txt b/Documentation/filesystems/vfs.txt index 70a056fe51a3..15c3fa7c89cc 100644 --- a/Documentation/filesystems/vfs.txt +++ b/Documentation/filesystems/vfs.txt @@ -923,6 +923,7 @@ struct dentry_operations { int (*d_compare)(const struct dentry *, const struct dentry *, unsigned int, const char *, const struct qstr *); int (*d_delete)(const struct dentry *); + int (*d_init)(struct dentry *); void (*d_release)(struct dentry *); void (*d_iput)(struct dentry *, struct inode *); char *(*d_dname)(struct dentry *, char *, int); @@ -995,6 +996,8 @@ struct dentry_operations { always cache a reachable dentry. d_delete must be constant and idempotent. + d_init: called when a dentry is allocated + d_release: called when a dentry is really deallocated d_iput: called when a dentry loses its inode (just prior to its diff --git a/fs/dcache.c b/fs/dcache.c index d5beef01cdfc..6d60a764c848 100644 --- a/fs/dcache.c +++ b/fs/dcache.c @@ -1569,6 +1569,7 @@ struct dentry *__d_alloc(struct super_block *sb, const struct qstr *name) { struct dentry *dentry; char *dname; + int err; dentry = kmem_cache_alloc(dentry_cache, GFP_KERNEL); if (!dentry) @@ -1627,6 +1628,16 @@ struct dentry *__d_alloc(struct super_block *sb, const struct qstr *name) INIT_LIST_HEAD(&dentry->d_child); d_set_d_op(dentry, dentry->d_sb->s_d_op); + if (dentry->d_op && dentry->d_op->d_init) { + err = dentry->d_op->d_init(dentry); + if (err) { + if (dname_external(dentry)) + kfree(external_name(dentry)); + kmem_cache_free(dentry_cache, dentry); + return NULL; + } + } + this_cpu_inc(nr_dentry); return dentry; diff --git a/include/linux/dcache.h b/include/linux/dcache.h index 14df83609c7f..98044a8d1487 100644 --- a/include/linux/dcache.h +++ b/include/linux/dcache.h @@ -133,6 +133,7 @@ struct dentry_operations { int (*d_compare)(const struct dentry *, const struct dentry *, unsigned int, const char *, const struct qstr *); int (*d_delete)(const struct dentry *); + int (*d_init)(struct dentry *); void (*d_release)(struct dentry *); void (*d_prune)(struct dentry *); void (*d_iput)(struct dentry *, struct inode *); -- 2.20.1