aufs: finfo core

The structure is very similar to iinfo and dinfo (in previous commits).
This commit is for non-dir files. For a directory, see later commit.
Signed-off-by: J. R. Okajima <hooanon05g@gmail.com>

fs/aufs/Makefile

@@ -15,7 +15,7 @@ aufs-y := module.o sbinfo.o super.o branch.o xino.o sysaufs.o opts.o \
 	cpup.o whout.o wbr_policy.o \
 	dinfo.o dentry.o \
 	dynop.o \
-	file.o \
+	finfo.o file.o \
 	dir.o \
 	iinfo.o inode.o i_op.o
 

fs/aufs/debug.c

@@ -180,6 +180,48 @@ void au_dpri_dentry(struct dentry *dentry)
 		do_pri_dentry(bindex, au_hdentry(dinfo, bindex)->hd_dentry);
 }
 
+static int do_pri_file(aufs_bindex_t bindex, struct file *file)
+{
+	char a[32];
+
+	if (!file || IS_ERR(file)) {
+		dpri("f%d: err %ld\n", bindex, PTR_ERR(file));
+		return -1;
+	}
+	a[0] = 0;
+	if (bindex < 0
+	    && !IS_ERR_OR_NULL(file->f_path.dentry)
+	    && au_test_aufs(file->f_path.dentry->d_sb)
+	    && au_fi(file))
+		snprintf(a, sizeof(a), ", gen %d",
+			 au_figen(file));
+	dpri("f%d: mode 0x%x, flags 0%o, cnt %ld, v %llu, pos %llu%s\n",
+	     bindex, file->f_mode, file->f_flags, (long)file_count(file),
+	     file->f_version, file->f_pos, a);
+	if (!IS_ERR_OR_NULL(file->f_path.dentry))
+		do_pri_dentry(bindex, file->f_path.dentry);
+	return 0;
+}
+
+void au_dpri_file(struct file *file)
+{
+	struct au_finfo *finfo;
+	int err;
+
+	err = do_pri_file(-1, file);
+	if (err
+	    || IS_ERR_OR_NULL(file->f_path.dentry)
+	    || !au_test_aufs(file->f_path.dentry->d_sb))
+		return;
+
+	finfo = au_fi(file);
+	if (!finfo)
+		return;
+	if (finfo->fi_btop < 0)
+		return;
+	do_pri_file(finfo->fi_btop, finfo->fi_htop.hf_file);
+}
+
 static int do_pri_br(aufs_bindex_t bindex, struct au_branch *br)
 {
 	struct vfsmount *mnt;

fs/aufs/debug.h

@@ -101,6 +101,8 @@ struct inode;
 void au_dpri_inode(struct inode *inode);
 void au_dpri_dalias(struct inode *inode);
 void au_dpri_dentry(struct dentry *dentry);
+struct file;
+void au_dpri_file(struct file *filp);
 struct super_block;
 void au_dpri_sb(struct super_block *sb);
 
@@ -130,6 +132,13 @@ void au_dbg_verify_kthread(void);
 	mutex_unlock(&au_dbg_mtx); \
 } while (0)
 
+#define AuDbgFile(f) do { \
+	mutex_lock(&au_dbg_mtx); \
+	AuDbg(#f "\n"); \
+	au_dpri_file(f); \
+	mutex_unlock(&au_dbg_mtx); \
+} while (0)
+
 #define AuDbgSb(sb) do { \
 	mutex_lock(&au_dbg_mtx); \
 	AuDbg(#sb "\n"); \
@@ -150,6 +159,7 @@ AuStubVoid(au_dbg_verify_kthread, void)
 #define AuDbgInode(i)		do {} while (0)
 #define AuDbgDAlias(i)		do {} while (0)
 #define AuDbgDentry(d)		do {} while (0)
+#define AuDbgFile(f)		do {} while (0)
 #define AuDbgSb(sb)		do {} while (0)
 #define AuDbgSym(addr)		do {} while (0)
 #endif /* CONFIG_AUFS_DEBUG */

fs/aufs/finfo.c

+// SPDX-License-Identifier: GPL-2.0
+/*
+ * Copyright (C) 2005-2019 Junjiro R. Okajima
+ */
+
+/*
+ * file private data
+ */
+
+#include "aufs.h"
+
+void au_hfput(struct au_hfile *hf, int execed)
+{
+	if (execed)
+		allow_write_access(hf->hf_file);
+	fput(hf->hf_file);
+	hf->hf_file = NULL;
+	au_lcnt_dec(&hf->hf_br->br_nfiles);
+	hf->hf_br = NULL;
+}
+
+void au_set_h_fptr(struct file *file, aufs_bindex_t bindex, struct file *val)
+{
+	struct au_finfo *finfo = au_fi(file);
+	struct au_hfile *hf;
+
+	AuDebugOn(finfo->fi_btop != bindex);
+	hf = &finfo->fi_htop;
+
+	if (hf && hf->hf_file)
+		au_hfput(hf, vfsub_file_execed(file));
+	if (val) {
+		FiMustWriteLock(file);
+		AuDebugOn(IS_ERR_OR_NULL(file->f_path.dentry));
+		hf->hf_file = val;
+		hf->hf_br = au_sbr(file->f_path.dentry->d_sb, bindex);
+	}
+}
+
+void au_update_figen(struct file *file)
+{
+	atomic_set(&au_fi(file)->fi_generation, au_digen(file->f_path.dentry));
+	/* smp_mb(); */ /* atomic_set */
+}
+
+/* ---------------------------------------------------------------------- */
+
+void au_finfo_fin(struct file *file)
+{
+	struct au_finfo *finfo;
+
+	finfo = au_fi(file);
+	AuRwDestroy(&finfo->fi_rwsem);
+	au_cache_free_finfo(finfo);
+}
+
+void au_fi_init_once(void *_finfo)
+{
+	struct au_finfo *finfo = _finfo;
+
+	au_rw_init(&finfo->fi_rwsem);
+}
+
+int au_finfo_init(struct file *file)
+{
+	int err;
+	struct au_finfo *finfo;
+	struct dentry *dentry;
+
+	err = -ENOMEM;
+	dentry = file->f_path.dentry;
+	finfo = au_cache_alloc_finfo();
+	if (unlikely(!finfo))
+		goto out;
+
+	err = 0;
+	au_rw_write_lock(&finfo->fi_rwsem);
+	finfo->fi_btop = -1;
+	atomic_set(&finfo->fi_generation, au_digen(dentry));
+	/* smp_mb(); */ /* atomic_set */
+
+	file->private_data = finfo;
+
+out:
+	return err;
+}

fs/aufs/module.c

@@ -98,6 +98,9 @@ static int __init au_cache_init(void)
 		au_cache[AuCache_ICNTNR] = AuCacheCtor(au_icntnr,
 						       au_icntnr_init_once);
 	if (au_cache[AuCache_ICNTNR])
+		au_cache[AuCache_FINFO] = AuCacheCtor(au_finfo,
+						      au_fi_init_once);
+	if (au_cache[AuCache_FINFO])
 		return 0;
 
 	au_cache_fin();

fs/aufs/module.h

@@ -15,6 +15,7 @@
 #include <linux/slab.h>
 #include "debug.h"
 #include "dentry.h"
+#include "file.h"
 #include "inode.h"
 
 struct path;
@@ -104,6 +105,7 @@ AuStubVoid(au_procfs_fin, void);
 enum {
 	AuCache_DINFO,
 	AuCache_ICNTNR,
+	AuCache_FINFO,
 	AuCache_HNOTIFY, /* must be last */
 	AuCache_Last
 };
@@ -136,6 +138,7 @@ extern struct kmem_cache *au_cache[AuCache_Last];
 
 AuCacheFuncs(dinfo, DINFO);
 AuCacheFuncs(icntnr, ICNTNR);
+AuCacheFuncs(finfo, FINFO);
 #ifdef CONFIG_AUFS_HNOTIFY
 AuCacheFuncs(hnotify, HNOTIFY);
 #endif

fs/aufs/vfsub.h

@@ -111,6 +111,23 @@ static inline loff_t vfsub_f_size_read(struct file *file)
 	return i_size_read(file_inode(file));
 }
 
+static inline unsigned int vfsub_file_flags(struct file *file)
+{
+	unsigned int flags;
+
+	spin_lock(&file->f_lock);
+	flags = file->f_flags;
+	spin_unlock(&file->f_lock);
+
+	return flags;
+}
+
+static inline int vfsub_file_execed(struct file *file)
+{
+	/* todo: direct access f_flags */
+	return !!(vfsub_file_flags(file) & __FMODE_EXEC);
+}
+
 /*
  * re-use branch fs's ioctl(FICLONE) while aufs itself doesn't support such
  * ioctl.