aufs: new inode

As a part of looking-up, construct a virtual inode.
After branch-management (add/del branches), the inode has to be
refreshed to represent a revealed file.
Signed-off-by: J. R. Okajima <hooanon05g@gmail.com>

fs/aufs/branch.h

@@ -220,6 +220,11 @@ int au_xino_init_br(struct super_block *sb, struct au_branch *br, ino_t hino,
 ino_t au_xino_new_ino(struct super_block *sb);
 void au_xino_delete_inode(struct inode *inode, const int unlinked);
 
+void au_xinondir_leave(struct super_block *sb, aufs_bindex_t bindex,
+		       ino_t h_ino, int idx);
+int au_xinondir_enter(struct super_block *sb, aufs_bindex_t bindex, ino_t h_ino,
+		      int *idx);
+
 int au_xino_path(struct seq_file *seq, struct file *file);
 
 /* ---------------------------------------------------------------------- */

fs/aufs/debug.c

@@ -101,7 +101,7 @@ void au_dpri_inode(struct inode *inode)
 
 	iinfo = au_ii(inode);
 	dpri("i-1: btop %d, bbot %d, gen %d\n",
-	     iinfo->ii_btop, iinfo->ii_bbot, au_iigen(inode));
+	     iinfo->ii_btop, iinfo->ii_bbot, au_iigen(inode, NULL));
 	if (iinfo->ii_btop < 0)
 		return;
 	hn = 0;

fs/aufs/export.c

@@ -223,7 +223,7 @@ static struct dentry *decode_by_ino(struct super_block *sb, ino_t ino,
 	sigen = au_sigen(sb);
 	if (unlikely(au_is_bad_inode(inode)
 		     || IS_DEADDIR(inode)
-		     || sigen != au_iigen(inode)))
+		     || sigen != au_iigen(inode, NULL)))
 		goto out_iput;
 
 	dentry = NULL;

fs/aufs/fstype.h

@@ -257,6 +257,14 @@ static inline int au_test_fs_notime(struct super_block *sb)
 		;
 }
 
+/* temporary support for i#1 in cramfs */
+static inline int au_test_fs_unique_ino(struct inode *inode)
+{
+	if (au_test_cramfs(inode->i_sb))
+		return inode->i_ino != 1;
+	return 1;
+}
+
 /* ---------------------------------------------------------------------- */
 
 /*

fs/aufs/iinfo.c

@@ -110,6 +110,10 @@ void au_update_iigen(struct inode *inode, int half)
 	iigen = &iinfo->ii_generation;
 	spin_lock(&iigen->ig_spin);
 	iigen->ig_generation = sigen;
+	if (half)
+		au_ig_fset(iigen->ig_flags, HALF_REFRESHED);
+	else
+		au_ig_fclr(iigen->ig_flags, HALF_REFRESHED);
 	spin_unlock(&iigen->ig_spin);
 }
 

fs/aufs/inode.c

@@ -7,6 +7,7 @@
  * inode functions
  */
 
+#include <linux/iversion.h>
 #include "aufs.h"
 
 struct inode *au_igrab(struct inode *inode)
@@ -18,6 +19,424 @@ struct inode *au_igrab(struct inode *inode)
 	return inode;
 }
 
+static void au_refresh_hinode_attr(struct inode *inode, int do_version)
+{
+	au_cpup_attr_all(inode, /*force*/0);
+	au_update_iigen(inode, /*half*/1);
+	if (do_version)
+		inode_inc_iversion(inode);
+}
+
+static int au_ii_refresh(struct inode *inode, int *update)
+{
+	int err, e, nbr;
+	umode_t type;
+	aufs_bindex_t bindex, new_bindex;
+	struct super_block *sb;
+	struct au_iinfo *iinfo;
+	struct au_hinode *p, *q, tmp;
+
+	AuDebugOn(au_is_bad_inode(inode));
+	IiMustWriteLock(inode);
+
+	*update = 0;
+	sb = inode->i_sb;
+	nbr = au_sbbot(sb) + 1;
+	type = inode->i_mode & S_IFMT;
+	iinfo = au_ii(inode);
+	err = au_hinode_realloc(iinfo, nbr, /*may_shrink*/0);
+	if (unlikely(err))
+		goto out;
+
+	AuDebugOn(iinfo->ii_btop < 0);
+	p = au_hinode(iinfo, iinfo->ii_btop);
+	for (bindex = iinfo->ii_btop; bindex <= iinfo->ii_bbot;
+	     bindex++, p++) {
+		if (!p->hi_inode)
+			continue;
+
+		AuDebugOn(type != (p->hi_inode->i_mode & S_IFMT));
+		new_bindex = au_br_index(sb, p->hi_id);
+		if (new_bindex == bindex)
+			continue;
+
+		if (new_bindex < 0) {
+			*update = 1;
+			au_hiput(p);
+			p->hi_inode = NULL;
+			continue;
+		}
+
+		if (new_bindex < iinfo->ii_btop)
+			iinfo->ii_btop = new_bindex;
+		if (iinfo->ii_bbot < new_bindex)
+			iinfo->ii_bbot = new_bindex;
+		/* swap two lower inode, and loop again */
+		q = au_hinode(iinfo, new_bindex);
+		tmp = *q;
+		*q = *p;
+		*p = tmp;
+		if (tmp.hi_inode) {
+			bindex--;
+			p--;
+		}
+	}
+	au_update_ibrange(inode, /*do_put_zero*/0);
+	au_hinode_realloc(iinfo, nbr, /*may_shrink*/1); /* harmless if err */
+	e = au_dy_irefresh(inode);
+	if (unlikely(e && !err))
+		err = e;
+
+out:
+	AuTraceErr(err);
+	return err;
+}
+
+int au_refresh_hinode_self(struct inode *inode)
+{
+	int err, update;
+
+	err = au_ii_refresh(inode, &update);
+	if (!err)
+		au_refresh_hinode_attr(inode, update && S_ISDIR(inode->i_mode));
+
+	AuTraceErr(err);
+	return err;
+}
+
+int au_refresh_hinode(struct inode *inode, struct dentry *dentry)
+{
+	int err, e, update;
+	unsigned int flags;
+	umode_t mode;
+	aufs_bindex_t bindex, bbot;
+	unsigned char isdir;
+	struct au_hinode *p;
+	struct au_iinfo *iinfo;
+
+	err = au_ii_refresh(inode, &update);
+	if (unlikely(err))
+		goto out;
+
+	update = 0;
+	iinfo = au_ii(inode);
+	p = au_hinode(iinfo, iinfo->ii_btop);
+	mode = (inode->i_mode & S_IFMT);
+	isdir = S_ISDIR(mode);
+	flags = au_hi_flags(inode, isdir);
+	bbot = au_dbbot(dentry);
+	for (bindex = au_dbtop(dentry); bindex <= bbot; bindex++) {
+		struct inode *h_i, *h_inode;
+		struct dentry *h_d;
+
+		h_d = au_h_dptr(dentry, bindex);
+		if (!h_d || d_is_negative(h_d))
+			continue;
+
+		h_inode = d_inode(h_d);
+		AuDebugOn(mode != (h_inode->i_mode & S_IFMT));
+		if (iinfo->ii_btop <= bindex && bindex <= iinfo->ii_bbot) {
+			h_i = au_h_iptr(inode, bindex);
+			if (h_i) {
+				if (h_i == h_inode)
+					continue;
+				err = -EIO;
+				break;
+			}
+		}
+		if (bindex < iinfo->ii_btop)
+			iinfo->ii_btop = bindex;
+		if (iinfo->ii_bbot < bindex)
+			iinfo->ii_bbot = bindex;
+		au_set_h_iptr(inode, bindex, au_igrab(h_inode), flags);
+		update = 1;
+	}
+	au_update_ibrange(inode, /*do_put_zero*/0);
+	e = au_dy_irefresh(inode);
+	if (unlikely(e && !err))
+		err = e;
+	if (!err)
+		au_refresh_hinode_attr(inode, update && isdir);
+
+out:
+	AuTraceErr(err);
+	return err;
+}
+
+static int set_inode(struct inode *inode, struct dentry *dentry)
+{
+	int err;
+	unsigned int flags;
+	umode_t mode;
+	aufs_bindex_t bindex, btop, btail;
+	unsigned char isdir;
+	struct dentry *h_dentry;
+	struct inode *h_inode;
+	struct au_iinfo *iinfo;
+
+	IiMustWriteLock(inode);
+
+	err = 0;
+	isdir = 0;
+	btop = au_dbtop(dentry);
+	h_dentry = au_h_dptr(dentry, btop);
+	h_inode = d_inode(h_dentry);
+	mode = h_inode->i_mode;
+	switch (mode & S_IFMT) {
+	case S_IFREG:
+		btail = au_dbtail(dentry);
+#if 0 /* re-commit later */
+		inode->i_op = aufs_iop + AuIop_OTHER;
+		inode->i_fop = &aufs_file_fop;
+#endif
+		err = au_dy_iaop(inode, btop, h_inode);
+		if (unlikely(err))
+			goto out;
+		break;
+	case S_IFDIR:
+		isdir = 1;
+		btail = au_dbtaildir(dentry);
+		/* inode->i_op = aufs_iop + AuIop_DIR; re-commit later */
+		inode->i_fop = &simple_dir_operations; /* re-commit later */
+		break;
+	case S_IFLNK:
+		btail = au_dbtail(dentry);
+		/* inode->i_op = aufs_iop + AuIop_SYMLINK; re-commit later */
+		break;
+	case S_IFBLK:
+	case S_IFCHR:
+	case S_IFIFO:
+	case S_IFSOCK:
+		btail = au_dbtail(dentry);
+		/* inode->i_op = aufs_iop + AuIop_OTHER; re-commit later */
+		init_special_inode(inode, mode, h_inode->i_rdev);
+		break;
+	default:
+		AuIOErr("Unknown file type 0%o\n", mode);
+		err = -EIO;
+		goto out;
+	}
+
+	/* do not set hnotify for whiteouted dirs (SHWH mode) */
+	flags = au_hi_flags(inode, isdir);
+	iinfo = au_ii(inode);
+	iinfo->ii_btop = btop;
+	iinfo->ii_bbot = btail;
+	for (bindex = btop; bindex <= btail; bindex++) {
+		h_dentry = au_h_dptr(dentry, bindex);
+		if (h_dentry)
+			au_set_h_iptr(inode, bindex,
+				      au_igrab(d_inode(h_dentry)), flags);
+	}
+	au_cpup_attr_all(inode, /*force*/1);
+
+out:
+	return err;
+}
+
+/*
+ * successful returns with iinfo write_locked
+ * minus: errno
+ * zero: success, matched
+ * plus: no error, but unmatched
+ */
+static int reval_inode(struct inode *inode, struct dentry *dentry)
+{
+	int err;
+	unsigned int gen, igflags;
+	aufs_bindex_t bindex, bbot;
+	struct inode *h_inode, *h_dinode;
+	struct dentry *h_dentry;
+
+	/*
+	 * before this function, if aufs got any iinfo lock, it must be only
+	 * one, the parent dir.
+	 * it can happen by UDBA and the obsoleted inode number.
+	 */
+	err = -EIO;
+	if (unlikely(inode->i_ino == parent_ino(dentry)))
+		goto out;
+
+	err = 1;
+	ii_write_lock_new_child(inode);
+	h_dentry = au_h_dptr(dentry, au_dbtop(dentry));
+	h_dinode = d_inode(h_dentry);
+	bbot = au_ibbot(inode);
+	for (bindex = au_ibtop(inode); bindex <= bbot; bindex++) {
+		h_inode = au_h_iptr(inode, bindex);
+		if (!h_inode || h_inode != h_dinode)
+			continue;
+
+		err = 0;
+		gen = au_iigen(inode, &igflags);
+		if (gen == au_digen(dentry)
+		    && !au_ig_ftest(igflags, HALF_REFRESHED))
+			break;
+
+		/* fully refresh inode using dentry */
+		err = au_refresh_hinode(inode, dentry);
+		if (!err)
+			au_update_iigen(inode, /*half*/0);
+		break;
+	}
+
+	if (unlikely(err))
+		ii_write_unlock(inode);
+out:
+	return err;
+}
+
+int au_ino(struct super_block *sb, aufs_bindex_t bindex, ino_t h_ino,
+	   unsigned int d_type, ino_t *ino)
+{
+	int err, idx;
+	const int isnondir = d_type != DT_DIR;
+
+	/* prevent hardlinked inode number from race condition */
+	if (isnondir) {
+		err = au_xinondir_enter(sb, bindex, h_ino, &idx);
+		if (unlikely(err))
+			goto out;
+	}
+
+	err = au_xino_read(sb, bindex, h_ino, ino);
+	if (unlikely(err))
+		goto out_xinondir;
+
+	if (!*ino) {
+		err = -EIO;
+		*ino = au_xino_new_ino(sb);
+		if (unlikely(!*ino))
+			goto out_xinondir;
+		err = au_xino_write(sb, bindex, h_ino, *ino);
+		if (unlikely(err))
+			goto out_xinondir;
+	}
+
+out_xinondir:
+	if (isnondir && idx >= 0)
+		au_xinondir_leave(sb, bindex, h_ino, idx);
+out:
+	return err;
+}
+
+/* successful returns with iinfo write_locked */
+/* todo: return with unlocked? */
+struct inode *au_new_inode(struct dentry *dentry, int must_new)
+{
+	struct inode *inode, *h_inode;
+	struct dentry *h_dentry;
+	struct super_block *sb;
+	ino_t h_ino, ino;
+	int err, idx, hlinked;
+	aufs_bindex_t btop;
+
+	sb = dentry->d_sb;
+	btop = au_dbtop(dentry);
+	h_dentry = au_h_dptr(dentry, btop);
+	h_inode = d_inode(h_dentry);
+	h_ino = h_inode->i_ino;
+	hlinked = !d_is_dir(h_dentry) && h_inode->i_nlink > 1;
+
+new_ino:
+	/*
+	 * stop 'race'-ing between hardlinks under different
+	 * parents.
+	 */
+	if (hlinked) {
+		err = au_xinondir_enter(sb, btop, h_ino, &idx);
+		inode = ERR_PTR(err);
+		if (unlikely(err))
+			goto out;
+	}
+
+	err = au_xino_read(sb, btop, h_ino, &ino);
+	inode = ERR_PTR(err);
+	if (unlikely(err))
+		goto out_xinondir;
+
+	if (!ino) {
+		ino = au_xino_new_ino(sb);
+		if (unlikely(!ino)) {
+			inode = ERR_PTR(-EIO);
+			goto out_xinondir;
+		}
+	}
+
+	AuDbg("i%lu\n", (unsigned long)ino);
+	inode = au_iget_locked(sb, ino);
+	err = PTR_ERR(inode);
+	if (IS_ERR(inode))
+		goto out_xinondir;
+
+	AuDbg("%lx, new %d\n", inode->i_state, !!(inode->i_state & I_NEW));
+	if (inode->i_state & I_NEW) {
+		ii_write_lock_new_child(inode);
+		err = set_inode(inode, dentry);
+		if (!err) {
+			unlock_new_inode(inode);
+			goto out_xinondir; /* success */
+		}
+
+		/*
+		 * iget_failed() calls iput(), but we need to call
+		 * ii_write_unlock() after iget_failed(). so dirty hack for
+		 * i_count.
+		 */
+		atomic_inc(&inode->i_count);
+		iget_failed(inode);
+		ii_write_unlock(inode);
+		au_xino_write(sb, btop, h_ino, /*ino*/0);
+		/* ignore this error */
+		goto out_iput;
+	} else if (!must_new && !IS_DEADDIR(inode) && inode->i_nlink) {
+		/*
+		 * horrible race condition between lookup, readdir and copyup
+		 * (or something).
+		 */
+		if (hlinked && idx >= 0)
+			au_xinondir_leave(sb, btop, h_ino, idx);
+		err = reval_inode(inode, dentry);
+		if (unlikely(err < 0)) {
+			hlinked = 0;
+			goto out_iput;
+		}
+		if (!err)
+			goto out; /* success */
+		else if (hlinked && idx >= 0) {
+			err = au_xinondir_enter(sb, btop, h_ino, &idx);
+			if (unlikely(err)) {
+				iput(inode);
+				inode = ERR_PTR(err);
+				goto out;
+			}
+		}
+	}
+
+	if (unlikely(au_test_fs_unique_ino(h_inode)))
+		AuWarn1("Warning: Un-notified UDBA or repeatedly renamed dir,"
+			" b%d, %s, %pd, hi%lu, i%lu.\n",
+			btop, au_sbtype(h_dentry->d_sb), dentry,
+			(unsigned long)h_ino, (unsigned long)ino);
+	ino = 0;
+	err = au_xino_write(sb, btop, h_ino, /*ino*/0);
+	if (!err) {
+		iput(inode);
+		if (hlinked && idx >= 0)
+			au_xinondir_leave(sb, btop, h_ino, idx);
+		goto new_ino;
+	}
+
+out_iput:
+	iput(inode);
+	inode = ERR_PTR(err);
+out_xinondir:
+	if (hlinked && idx >= 0)
+		au_xinondir_leave(sb, btop, h_ino, idx);
+out:
+	return inode;
+}
+
 /* ---------------------------------------------------------------------- */
 
 int au_test_ro(struct super_block *sb, aufs_bindex_t bindex,

fs/aufs/inode.h

@@ -39,9 +39,17 @@ struct au_hinode {
 	struct dentry		*hi_whdentry;
 };
 
+/* ig_flags */
+#define AuIG_HALF_REFRESHED		1
+#define au_ig_ftest(flags, name)	((flags) & AuIG_##name)
+#define au_ig_fset(flags, name) \
+	do { (flags) |= AuIG_##name; } while (0)
+#define au_ig_fclr(flags, name) \
+	do { (flags) &= ~AuIG_##name; } while (0)
+
 struct au_iigen {
 	spinlock_t	ig_spin;
-	__u32		ig_generation;
+	__u32		ig_generation, ig_flags;
 };
 
 struct au_iinfo {
@@ -106,6 +114,11 @@ static inline struct au_iinfo *au_ii(struct inode *inode)
 
 /* inode.c */
 struct inode *au_igrab(struct inode *inode);
+int au_refresh_hinode_self(struct inode *inode);
+int au_refresh_hinode(struct inode *inode, struct dentry *dentry);
+int au_ino(struct super_block *sb, aufs_bindex_t bindex, ino_t h_ino,
+	   unsigned int d_type, ino_t *ino);
+struct inode *au_new_inode(struct dentry *dentry, int must_new);
 int au_test_ro(struct super_block *sb, aufs_bindex_t bindex,
 	       struct inode *inode);
 int au_test_h_perm(struct inode *h_inode, int mask);
@@ -252,7 +265,7 @@ static inline void au_icntnr_init(struct au_icntnr *c)
 #endif
 }
 
-static inline unsigned int au_iigen(struct inode *inode)
+static inline unsigned int au_iigen(struct inode *inode, unsigned int *igflags)
 {
 	unsigned int gen;
 	struct au_iinfo *iinfo;
@@ -261,6 +274,8 @@ static inline unsigned int au_iigen(struct inode *inode)
 	iinfo = au_ii(inode);
 	iigen = &iinfo->ii_generation;
 	spin_lock(&iigen->ig_spin);
+	if (igflags)
+		*igflags = iigen->ig_flags;
 	gen = iigen->ig_generation;
 	spin_unlock(&iigen->ig_spin);
 
@@ -296,7 +311,7 @@ static inline int au_iigen_test(struct inode *inode, unsigned int sigen)
 	int err;
 
 	err = 0;
-	if (unlikely(inode && au_iigen(inode) != sigen))
+	if (unlikely(inode && au_iigen(inode, NULL) != sigen))
 		err = -EIO;
 
 	return err;

fs/aufs/xino.c

@@ -1806,6 +1806,103 @@ void au_xino_delete_inode(struct inode *inode, const int unlinked)
 
 /* ---------------------------------------------------------------------- */
 
+static int au_xinondir_find(struct au_xino *xi, ino_t h_ino)
+{
+	int found, total, i;
+
+	found = -1;
+	total = xi->xi_nondir.total;
+	for (i = 0; i < total; i++) {
+		if (xi->xi_nondir.array[i] != h_ino)
+			continue;
+		found = i;
+		break;
+	}
+
+	return found;
+}
+
+static int au_xinondir_expand(struct au_xino *xi)
+{
+	int err, sz;
+	ino_t *p;
+
+	BUILD_BUG_ON(KMALLOC_MAX_SIZE > INT_MAX);
+
+	err = -ENOMEM;
+	sz = xi->xi_nondir.total * sizeof(ino_t);
+	if (unlikely(sz > KMALLOC_MAX_SIZE / 2))
+		goto out;
+	p = au_kzrealloc(xi->xi_nondir.array, sz, sz << 1, GFP_ATOMIC,
+			 /*may_shrink*/0);
+	if (p) {
+		xi->xi_nondir.array = p;
+		xi->xi_nondir.total <<= 1;
+		AuDbg("xi_nondir.total %d\n", xi->xi_nondir.total);
+		err = 0;
+	}
+
+out:
+	return err;
+}
+
+void au_xinondir_leave(struct super_block *sb, aufs_bindex_t bindex,
+		       ino_t h_ino, int idx)
+{
+	struct au_xino *xi;
+
+	AuDebugOn(!au_opt_test(au_mntflags(sb), XINO));
+	xi = au_sbr(sb, bindex)->br_xino;
+	AuDebugOn(idx < 0 || xi->xi_nondir.total <= idx);
+
+	spin_lock(&xi->xi_nondir.spin);
+	AuDebugOn(xi->xi_nondir.array[idx] != h_ino);
+	xi->xi_nondir.array[idx] = 0;
+	spin_unlock(&xi->xi_nondir.spin);
+	wake_up_all(&xi->xi_nondir.wqh);
+}
+
+int au_xinondir_enter(struct super_block *sb, aufs_bindex_t bindex, ino_t h_ino,
+		      int *idx)
+{
+	int err, found, empty;
+	struct au_xino *xi;
+
+	err = 0;
+	*idx = -1;
+	if (!au_opt_test(au_mntflags(sb), XINO))
+		goto out; /* no xino */
+
+	xi = au_sbr(sb, bindex)->br_xino;
+
+again:
+	spin_lock(&xi->xi_nondir.spin);
+	found = au_xinondir_find(xi, h_ino);
+	if (found == -1) {
+		empty = au_xinondir_find(xi, /*h_ino*/0);
+		if (empty == -1) {
+			empty = xi->xi_nondir.total;
+			err = au_xinondir_expand(xi);
+			if (unlikely(err))
+				goto out_unlock;
+		}
+		xi->xi_nondir.array[empty] = h_ino;
+		*idx = empty;
+	} else {
+		spin_unlock(&xi->xi_nondir.spin);
+		wait_event(xi->xi_nondir.wqh,
+			   xi->xi_nondir.array[found] != h_ino);
+		goto again;
+	}
+
+out_unlock:
+	spin_unlock(&xi->xi_nondir.spin);
+out:
+	return err;
+}
+
+/* ---------------------------------------------------------------------- */
+
 int au_xino_path(struct seq_file *seq, struct file *file)
 {
 	int err;