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VFS: Put a small type field into struct dentry::d_flags

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Put a type field into struct dentry::d_flags to indicate if the dentry is one
of the following types that relate particularly to pathwalk:

	Miss (negative dentry)
	Directory
	"Automount" directory (defective - no i_op->lookup())
	Symlink
	Other (regular, socket, fifo, device)

The type field is set to one of the first five types on a dentry by calls to
__d_instantiate() and d_obtain_alias() from information in the inode (if one is
given).

The type is cleared by dentry_unlink_inode() when it reconstitutes an existing
dentry as a negative dentry.

Accessors provided are:

	d_set_type(dentry, type)
	d_is_directory(dentry)
	d_is_autodir(dentry)
	d_is_symlink(dentry)
	d_is_file(dentry)
	d_is_negative(dentry)
	d_is_positive(dentry)

A bunch of checks in pathname resolution switched to those.

Signed-off-by: David Howells <dhowells@redhat.com>
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
This commit is contained in:
David Howells
2013-09-12 19:22:53 +01:00
committed by Al Viro
parent afabada957
commit b18825a7c8
3 changed files with 158 additions and 82 deletions
Download Patch File Download Diff File Expand all files Collapse all files

103
include/linux/dcache.h
View File

@@ -169,13 +169,13 @@ struct dentry_operations {
*/
/* d_flags entries */
#define DCACHE_OP_HASH 0x0001
#define DCACHE_OP_COMPARE 0x0002
#define DCACHE_OP_REVALIDATE 0x0004
#define DCACHE_OP_DELETE 0x0008
#define DCACHE_OP_PRUNE 0x0010
#define DCACHE_OP_HASH 0x00000001
#define DCACHE_OP_COMPARE 0x00000002
#define DCACHE_OP_REVALIDATE 0x00000004
#define DCACHE_OP_DELETE 0x00000008
#define DCACHE_OP_PRUNE 0x00000010
#define DCACHE_DISCONNECTED 0x0020
#define DCACHE_DISCONNECTED 0x00000020
/* This dentry is possibly not currently connected to the dcache tree, in
* which case its parent will either be itself, or will have this flag as
* well. nfsd will not use a dentry with this bit set, but will first
@@ -186,30 +186,38 @@ struct dentry_operations {
* dentry into place and return that dentry rather than the passed one,
* typically using d_splice_alias. */
#define DCACHE_REFERENCED 0x0040 /* Recently used, don't discard. */
#define DCACHE_RCUACCESS 0x0080 /* Entry has ever been RCU-visible */
#define DCACHE_REFERENCED 0x00000040 /* Recently used, don't discard. */
#define DCACHE_RCUACCESS 0x00000080 /* Entry has ever been RCU-visible */
#define DCACHE_CANT_MOUNT 0x0100
#define DCACHE_GENOCIDE 0x0200
#define DCACHE_SHRINK_LIST 0x0400
#define DCACHE_CANT_MOUNT 0x00000100
#define DCACHE_GENOCIDE 0x00000200
#define DCACHE_SHRINK_LIST 0x00000400
#define DCACHE_OP_WEAK_REVALIDATE 0x0800
#define DCACHE_OP_WEAK_REVALIDATE 0x00000800
#define DCACHE_NFSFS_RENAMED 0x1000
#define DCACHE_NFSFS_RENAMED 0x00001000
/* this dentry has been "silly renamed" and has to be deleted on the last
* dput() */
#define DCACHE_COOKIE 0x2000 /* For use by dcookie subsystem */
#define DCACHE_FSNOTIFY_PARENT_WATCHED 0x4000
#define DCACHE_COOKIE 0x00002000 /* For use by dcookie subsystem */
#define DCACHE_FSNOTIFY_PARENT_WATCHED 0x00004000
/* Parent inode is watched by some fsnotify listener */
#define DCACHE_MOUNTED 0x10000 /* is a mountpoint */
#define DCACHE_NEED_AUTOMOUNT 0x20000 /* handle automount on this dir */
#define DCACHE_MANAGE_TRANSIT 0x40000 /* manage transit from this dirent */
#define DCACHE_DENTRY_KILLED 0x00008000
#define DCACHE_MOUNTED 0x00010000 /* is a mountpoint */
#define DCACHE_NEED_AUTOMOUNT 0x00020000 /* handle automount on this dir */
#define DCACHE_MANAGE_TRANSIT 0x00040000 /* manage transit from this dirent */
#define DCACHE_MANAGED_DENTRY \
(DCACHE_MOUNTED|DCACHE_NEED_AUTOMOUNT|DCACHE_MANAGE_TRANSIT)
#define DCACHE_LRU_LIST 0x80000
#define DCACHE_DENTRY_KILLED 0x100000
#define DCACHE_LRU_LIST 0x00080000
#define DCACHE_ENTRY_TYPE 0x00700000
#define DCACHE_MISS_TYPE 0x00000000 /* Negative dentry */
#define DCACHE_DIRECTORY_TYPE 0x00100000 /* Normal directory */
#define DCACHE_AUTODIR_TYPE 0x00200000 /* Lookupless directory (presumed automount) */
#define DCACHE_SYMLINK_TYPE 0x00300000 /* Symlink */
#define DCACHE_FILE_TYPE 0x00400000 /* Other file type */
extern seqlock_t rename_lock;
@@ -394,6 +402,61 @@ static inline bool d_mountpoint(const struct dentry *dentry)
return dentry->d_flags & DCACHE_MOUNTED;
}
/*
* Directory cache entry type accessor functions.
*/
static inline void __d_set_type(struct dentry *dentry, unsigned type)
{
dentry->d_flags = (dentry->d_flags & ~DCACHE_ENTRY_TYPE) | type;
}
static inline void __d_clear_type(struct dentry *dentry)
{
__d_set_type(dentry, DCACHE_MISS_TYPE);
}
static inline void d_set_type(struct dentry *dentry, unsigned type)
{
spin_lock(&dentry->d_lock);
__d_set_type(dentry, type);
spin_unlock(&dentry->d_lock);
}
static inline unsigned __d_entry_type(const struct dentry *dentry)
{
return dentry->d_flags & DCACHE_ENTRY_TYPE;
}
static inline bool d_is_directory(const struct dentry *dentry)
{
return __d_entry_type(dentry) == DCACHE_DIRECTORY_TYPE;
}
static inline bool d_is_autodir(const struct dentry *dentry)
{
return __d_entry_type(dentry) == DCACHE_AUTODIR_TYPE;
}
static inline bool d_is_symlink(const struct dentry *dentry)
{
return __d_entry_type(dentry) == DCACHE_SYMLINK_TYPE;
}
static inline bool d_is_file(const struct dentry *dentry)
{
return __d_entry_type(dentry) == DCACHE_FILE_TYPE;
}
static inline bool d_is_negative(const struct dentry *dentry)
{
return __d_entry_type(dentry) == DCACHE_MISS_TYPE;
}
static inline bool d_is_positive(const struct dentry *dentry)
{
return !d_is_negative(dentry);
}
extern int sysctl_vfs_cache_pressure;
static inline unsigned long vfs_pressure_ratio(unsigned long val)