[PATCH 24/29] Unionfs: debugging infrastructure

[Erez Zadok]

Signed-off-by: Erez Zadok <ezk@xxxxxxxxxxxxx>
---
 fs/unionfs/debug.c |  533 ++++++++++++++++++++++++++++++++++++++++++++++++++++
 1 files changed, 533 insertions(+), 0 deletions(-)
 create mode 100644 fs/unionfs/debug.c

diff --git a/fs/unionfs/debug.c b/fs/unionfs/debug.c
new file mode 100644
index 0000000..d154c32
--- /dev/null
+++ b/fs/unionfs/debug.c
@@ -0,0 +1,533 @@
+/*
+ * Copyright (c) 2003-2007 Erez Zadok
+ * Copyright (c) 2005-2007 Josef 'Jeff' Sipek
+ * Copyright (c) 2003-2007 Stony Brook University
+ * Copyright (c) 2003-2007 The Research Foundation of SUNY
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License version 2 as
+ * published by the Free Software Foundation.
+ */
+
+#include "union.h"
+
+/*
+ * Helper debugging functions for maintainers (and for users to report back
+ * useful information back to maintainers)
+ */
+
+/* it's always useful to know what part of the code called us */
+#define PRINT_CALLER(fname, fxn, line)					\
+	do {								\
+		if (!printed_caller) {					\
+			pr_debug("PC:%s:%s:%d\n", (fname), (fxn), (line)); \
+			printed_caller = 1;				\
+		}							\
+	} while (0)
+
+/*
+ * __unionfs_check_{inode,dentry,file} perform exhaustive sanity checking on
+ * the fan-out of various Unionfs objects.  We check that no lower objects
+ * exist  outside the start/end branch range; that all objects within are
+ * non-NULL (with some allowed exceptions); that for every lower file
+ * there's a lower dentry+inode; that the start/end ranges match for all
+ * corresponding lower objects; that open files/symlinks have only one lower
+ * objects, but directories can have several; and more.
+ */
+void __unionfs_check_inode(const struct inode *inode,
+			   const char *fname, const char *fxn, int line)
+{
+	int bindex;
+	int istart, iend;
+	struct inode *lower_inode;
+	struct super_block *sb;
+	int printed_caller = 0;
+	void *poison_ptr;
+
+	/* for inodes now */
+	BUG_ON(!inode);
+	sb = inode->i_sb;
+	istart = ibstart(inode);
+	iend = ibend(inode);
+	/* don't check inode if no lower branches */
+	if (istart < 0 && iend < 0)
+		return;
+	if (unlikely(istart > iend)) {
+		PRINT_CALLER(fname, fxn, line);
+		pr_debug(" Ci0: inode=%p istart/end=%d:%d\n",
+			 inode, istart, iend);
+	}
+	if (unlikely((istart == -1 && iend != -1) ||
+		     (istart != -1 && iend == -1))) {
+		PRINT_CALLER(fname, fxn, line);
+		pr_debug(" Ci1: inode=%p istart/end=%d:%d\n",
+			 inode, istart, iend);
+	}
+	if (!S_ISDIR(inode->i_mode)) {
+		if (unlikely(iend != istart)) {
+			PRINT_CALLER(fname, fxn, line);
+			pr_debug(" Ci2: inode=%p istart=%d iend=%d\n",
+				 inode, istart, iend);
+		}
+	}
+
+	for (bindex = sbstart(sb); bindex < sbmax(sb); bindex++) {
+		if (unlikely(!UNIONFS_I(inode))) {
+			PRINT_CALLER(fname, fxn, line);
+			pr_debug(" Ci3: no inode_info %p\n", inode);
+			return;
+		}
+		if (unlikely(!UNIONFS_I(inode)->lower_inodes)) {
+			PRINT_CALLER(fname, fxn, line);
+			pr_debug(" Ci4: no lower_inodes %p\n", inode);
+			return;
+		}
+		lower_inode = unionfs_lower_inode_idx(inode, bindex);
+		if (lower_inode) {
+			memset(&poison_ptr, POISON_INUSE, sizeof(void *));
+			if (unlikely(bindex < istart || bindex > iend)) {
+				PRINT_CALLER(fname, fxn, line);
+				pr_debug(" Ci5: inode/linode=%p:%p bindex=%d "
+					 "istart/end=%d:%d\n", inode,
+					 lower_inode, bindex, istart, iend);
+			} else if (unlikely(lower_inode == poison_ptr)) {
+				/* freed inode! */
+				PRINT_CALLER(fname, fxn, line);
+				pr_debug(" Ci6: inode/linode=%p:%p bindex=%d "
+					 "istart/end=%d:%d\n", inode,
+					 lower_inode, bindex, istart, iend);
+			}
+			continue;
+		}
+		/* if we get here, then lower_inode == NULL */
+		if (bindex < istart || bindex > iend)
+			continue;
+		/*
+		 * directories can have NULL lower inodes in b/t start/end,
+		 * but NOT if at the start/end range.
+		 */
+		if (unlikely(S_ISDIR(inode->i_mode) &&
+			     bindex > istart && bindex < iend))
+			continue;
+		PRINT_CALLER(fname, fxn, line);
+		pr_debug(" Ci7: inode/linode=%p:%p "
+			 "bindex=%d istart/end=%d:%d\n",
+			 inode, lower_inode, bindex, istart, iend);
+	}
+}
+
+void __unionfs_check_dentry(const struct dentry *dentry,
+			    const char *fname, const char *fxn, int line)
+{
+	int bindex;
+	int dstart, dend, istart, iend;
+	struct dentry *lower_dentry;
+	struct inode *inode, *lower_inode;
+	struct super_block *sb;
+	struct vfsmount *lower_mnt;
+	int printed_caller = 0;
+	void *poison_ptr;
+
+	BUG_ON(!dentry);
+	sb = dentry->d_sb;
+	inode = dentry->d_inode;
+	dstart = dbstart(dentry);
+	dend = dbend(dentry);
+	/* don't check dentry/mnt if no lower branches */
+	if (dstart < 0 && dend < 0)
+		goto check_inode;
+	BUG_ON(dstart > dend);
+
+	if (unlikely((dstart == -1 && dend != -1) ||
+		     (dstart != -1 && dend == -1))) {
+		PRINT_CALLER(fname, fxn, line);
+		pr_debug(" CD0: dentry=%p dstart/end=%d:%d\n",
+			 dentry, dstart, dend);
+	}
+	/*
+	 * check for NULL dentries inside the start/end range, or
+	 * non-NULL dentries outside the start/end range.
+	 */
+	for (bindex = sbstart(sb); bindex < sbmax(sb); bindex++) {
+		lower_dentry = unionfs_lower_dentry_idx(dentry, bindex);
+		if (lower_dentry) {
+			if (unlikely(bindex < dstart || bindex > dend)) {
+				PRINT_CALLER(fname, fxn, line);
+				pr_debug(" CD1: dentry/lower=%p:%p(%p) "
+					 "bindex=%d dstart/end=%d:%d\n",
+					 dentry, lower_dentry,
+					 (lower_dentry ? lower_dentry->d_inode :
+					  (void *) -1L),
+					 bindex, dstart, dend);
+			}
+		} else {	/* lower_dentry == NULL */
+			if (bindex < dstart || bindex > dend)
+				continue;
+			/*
+			 * Directories can have NULL lower inodes in b/t
+			 * start/end, but NOT if at the start/end range.
+			 * Ignore this rule, however, if this is a NULL
+			 * dentry or a deleted dentry.
+			 */
+			if (unlikely(!d_deleted((struct dentry *) dentry) &&
+				     inode &&
+				     !(inode && S_ISDIR(inode->i_mode) &&
+				       bindex > dstart && bindex < dend))) {
+				PRINT_CALLER(fname, fxn, line);
+				pr_debug(" CD2: dentry/lower=%p:%p(%p) "
+					 "bindex=%d dstart/end=%d:%d\n",
+					 dentry, lower_dentry,
+					 (lower_dentry ?
+					  lower_dentry->d_inode :
+					  (void *) -1L),
+					 bindex, dstart, dend);
+			}
+		}
+	}
+
+	/* check for vfsmounts same as for dentries */
+	for (bindex = sbstart(sb); bindex < sbmax(sb); bindex++) {
+		lower_mnt = unionfs_lower_mnt_idx(dentry, bindex);
+		if (lower_mnt) {
+			if (unlikely(bindex < dstart || bindex > dend)) {
+				PRINT_CALLER(fname, fxn, line);
+				pr_debug(" CM0: dentry/lmnt=%p:%p bindex=%d "
+					 "dstart/end=%d:%d\n", dentry,
+					 lower_mnt, bindex, dstart, dend);
+			}
+		} else {	/* lower_mnt == NULL */
+			if (bindex < dstart || bindex > dend)
+				continue;
+			/*
+			 * Directories can have NULL lower inodes in b/t
+			 * start/end, but NOT if at the start/end range.
+			 * Ignore this rule, however, if this is a NULL
+			 * dentry.
+			 */
+			if (unlikely(inode &&
+				     !(inode && S_ISDIR(inode->i_mode) &&
+				       bindex > dstart && bindex < dend))) {
+				PRINT_CALLER(fname, fxn, line);
+				pr_debug(" CM1: dentry/lmnt=%p:%p "
+					 "bindex=%d dstart/end=%d:%d\n",
+					 dentry, lower_mnt, bindex,
+					 dstart, dend);
+			}
+		}
+	}
+
+check_inode:
+	/* for inodes now */
+	if (!inode)
+		return;
+	istart = ibstart(inode);
+	iend = ibend(inode);
+	/* don't check inode if no lower branches */
+	if (istart < 0 && iend < 0)
+		return;
+	BUG_ON(istart > iend);
+	if (unlikely((istart == -1 && iend != -1) ||
+		     (istart != -1 && iend == -1))) {
+		PRINT_CALLER(fname, fxn, line);
+		pr_debug(" CI0: dentry/inode=%p:%p istart/end=%d:%d\n",
+			 dentry, inode, istart, iend);
+	}
+	if (unlikely(istart != dstart)) {
+		PRINT_CALLER(fname, fxn, line);
+		pr_debug(" CI1: dentry/inode=%p:%p istart=%d dstart=%d\n",
+			 dentry, inode, istart, dstart);
+	}
+	if (unlikely(iend != dend)) {
+		PRINT_CALLER(fname, fxn, line);
+		pr_debug(" CI2: dentry/inode=%p:%p iend=%d dend=%d\n",
+			 dentry, inode, iend, dend);
+	}
+
+	if (!S_ISDIR(inode->i_mode)) {
+		if (unlikely(dend != dstart)) {
+			PRINT_CALLER(fname, fxn, line);
+			pr_debug(" CI3: dentry/inode=%p:%p dstart=%d dend=%d\n",
+				 dentry, inode, dstart, dend);
+		}
+		if (unlikely(iend != istart)) {
+			PRINT_CALLER(fname, fxn, line);
+			pr_debug(" CI4: dentry/inode=%p:%p istart=%d iend=%d\n",
+				 dentry, inode, istart, iend);
+		}
+	}
+
+	for (bindex = sbstart(sb); bindex < sbmax(sb); bindex++) {
+		lower_inode = unionfs_lower_inode_idx(inode, bindex);
+		if (lower_inode) {
+			memset(&poison_ptr, POISON_INUSE, sizeof(void *));
+			if (unlikely(bindex < istart || bindex > iend)) {
+				PRINT_CALLER(fname, fxn, line);
+				pr_debug(" CI5: dentry/linode=%p:%p bindex=%d "
+					 "istart/end=%d:%d\n", dentry,
+					 lower_inode, bindex, istart, iend);
+			} else if (unlikely(lower_inode == poison_ptr)) {
+				/* freed inode! */
+				PRINT_CALLER(fname, fxn, line);
+				pr_debug(" CI6: dentry/linode=%p:%p bindex=%d "
+					 "istart/end=%d:%d\n", dentry,
+					 lower_inode, bindex, istart, iend);
+			}
+			continue;
+		}
+		/* if we get here, then lower_inode == NULL */
+		if (bindex < istart || bindex > iend)
+			continue;
+		/*
+		 * directories can have NULL lower inodes in b/t start/end,
+		 * but NOT if at the start/end range.
+		 */
+		if (unlikely(S_ISDIR(inode->i_mode) &&
+			     bindex > istart && bindex < iend))
+			continue;
+		PRINT_CALLER(fname, fxn, line);
+		pr_debug(" CI7: dentry/linode=%p:%p "
+			 "bindex=%d istart/end=%d:%d\n",
+			 dentry, lower_inode, bindex, istart, iend);
+	}
+
+	/*
+	 * If it's a directory, then intermediate objects b/t start/end can
+	 * be NULL.  But, check that all three are NULL: lower dentry, mnt,
+	 * and inode.
+	 */
+	if (dstart >= 0 && dend >= 0 && S_ISDIR(inode->i_mode))
+		for (bindex = dstart+1; bindex < dend; bindex++) {
+			lower_inode = unionfs_lower_inode_idx(inode, bindex);
+			lower_dentry = unionfs_lower_dentry_idx(dentry,
+								bindex);
+			lower_mnt = unionfs_lower_mnt_idx(dentry, bindex);
+			if (unlikely(!((lower_inode && lower_dentry &&
+					lower_mnt) ||
+				       (!lower_inode &&
+					!lower_dentry && !lower_mnt)))) {
+				PRINT_CALLER(fname, fxn, line);
+				pr_debug(" Cx: lmnt/ldentry/linode=%p:%p:%p "
+					 "bindex=%d dstart/end=%d:%d\n",
+					 lower_mnt, lower_dentry, lower_inode,
+					 bindex, dstart, dend);
+			}
+		}
+	/* check if lower inode is newer than upper one (it shouldn't) */
+	if (unlikely(is_newer_lower(dentry))) {
+		PRINT_CALLER(fname, fxn, line);
+		for (bindex = ibstart(inode); bindex <= ibend(inode);
+		     bindex++) {
+			lower_inode = unionfs_lower_inode_idx(inode, bindex);
+			if (unlikely(!lower_inode))
+				continue;
+			pr_debug(" CI8: bindex=%d mtime/lmtime=%lu.%lu/%lu.%lu "
+				 "ctime/lctime=%lu.%lu/%lu.%lu\n",
+				 bindex,
+				 inode->i_mtime.tv_sec,
+				 inode->i_mtime.tv_nsec,
+				 lower_inode->i_mtime.tv_sec,
+				 lower_inode->i_mtime.tv_nsec,
+				 inode->i_ctime.tv_sec,
+				 inode->i_ctime.tv_nsec,
+				 lower_inode->i_ctime.tv_sec,
+				 lower_inode->i_ctime.tv_nsec);
+		}
+	}
+}
+
+void __unionfs_check_file(const struct file *file,
+			  const char *fname, const char *fxn, int line)
+{
+	int bindex;
+	int dstart, dend, fstart, fend;
+	struct dentry *dentry;
+	struct file *lower_file;
+	struct inode *inode;
+	struct super_block *sb;
+	int printed_caller = 0;
+
+	BUG_ON(!file);
+	dentry = file->f_path.dentry;
+	sb = dentry->d_sb;
+	dstart = dbstart(dentry);
+	dend = dbend(dentry);
+	BUG_ON(dstart > dend);
+	fstart = fbstart(file);
+	fend = fbend(file);
+	BUG_ON(fstart > fend);
+
+	if (unlikely((fstart == -1 && fend != -1) ||
+		     (fstart != -1 && fend == -1))) {
+		PRINT_CALLER(fname, fxn, line);
+		pr_debug(" CF0: file/dentry=%p:%p fstart/end=%d:%d\n",
+			 file, dentry, fstart, fend);
+	}
+	if (unlikely(fstart != dstart)) {
+		PRINT_CALLER(fname, fxn, line);
+		pr_debug(" CF1: file/dentry=%p:%p fstart=%d dstart=%d\n",
+			 file, dentry, fstart, dstart);
+	}
+	if (unlikely(fend != dend)) {
+		PRINT_CALLER(fname, fxn, line);
+		pr_debug(" CF2: file/dentry=%p:%p fend=%d dend=%d\n",
+			 file, dentry, fend, dend);
+	}
+	inode = dentry->d_inode;
+	if (!S_ISDIR(inode->i_mode)) {
+		if (unlikely(fend != fstart)) {
+			PRINT_CALLER(fname, fxn, line);
+			pr_debug(" CF3: file/inode=%p:%p fstart=%d fend=%d\n",
+				 file, inode, fstart, fend);
+		}
+		if (unlikely(dend != dstart)) {
+			PRINT_CALLER(fname, fxn, line);
+			pr_debug(" CF4: file/dentry=%p:%p dstart=%d dend=%d\n",
+				 file, dentry, dstart, dend);
+		}
+	}
+
+	/*
+	 * check for NULL dentries inside the start/end range, or
+	 * non-NULL dentries outside the start/end range.
+	 */
+	for (bindex = sbstart(sb); bindex < sbmax(sb); bindex++) {
+		lower_file = unionfs_lower_file_idx(file, bindex);
+		if (lower_file) {
+			if (unlikely(bindex < fstart || bindex > fend)) {
+				PRINT_CALLER(fname, fxn, line);
+				pr_debug(" CF5: file/lower=%p:%p bindex=%d "
+					 "fstart/end=%d:%d\n", file,
+					 lower_file, bindex, fstart, fend);
+			}
+		} else {	/* lower_file == NULL */
+			if (bindex >= fstart && bindex <= fend) {
+				/*
+				 * directories can have NULL lower inodes in
+				 * b/t start/end, but NOT if at the
+				 * start/end range.
+				 */
+				if (unlikely(!(S_ISDIR(inode->i_mode) &&
+					       bindex > fstart &&
+					       bindex < fend))) {
+					PRINT_CALLER(fname, fxn, line);
+					pr_debug(" CF6: file/lower=%p:%p "
+						 "bindex=%d fstart/end=%d:%d\n",
+						 file, lower_file, bindex,
+						 fstart, fend);
+				}
+			}
+		}
+	}
+
+	__unionfs_check_dentry(dentry, fname, fxn, line);
+}
+
+void __unionfs_check_nd(const struct nameidata *nd,
+			const char *fname, const char *fxn, int line)
+{
+	struct file *file;
+	int printed_caller = 0;
+
+	if (unlikely(!nd))
+		return;
+	if (nd->flags & LOOKUP_OPEN) {
+		file = nd->intent.open.file;
+		if (unlikely(file->f_path.dentry &&
+			     strcmp(file->f_path.dentry->d_sb->s_type->name,
+				    UNIONFS_NAME))) {
+			PRINT_CALLER(fname, fxn, line);
+			pr_debug(" CND1: lower_file of type %s\n",
+				 file->f_path.dentry->d_sb->s_type->name);
+			BUG();
+		}
+	}
+}
+
+/* useful to track vfsmount leaks that could cause EBUSY on unmount */
+void __show_branch_counts(const struct super_block *sb,
+			  const char *file, const char *fxn, int line)
+{
+	int i;
+	struct vfsmount *mnt;
+
+	pr_debug("BC:");
+	for (i = 0; i < sbmax(sb); i++) {
+		if (likely(sb->s_root))
+			mnt = UNIONFS_D(sb->s_root)->lower_paths[i].mnt;
+		else
+			mnt = NULL;
+		printk(KERN_CONT "%d:",
+		       (mnt ? atomic_read(&mnt->mnt_count) : -99));
+	}
+	printk(KERN_CONT "%s:%s:%d\n", file, fxn, line);
+}
+
+void __show_inode_times(const struct inode *inode,
+			const char *file, const char *fxn, int line)
+{
+	struct inode *lower_inode;
+	int bindex;
+
+	for (bindex = ibstart(inode); bindex <= ibend(inode); bindex++) {
+		lower_inode = unionfs_lower_inode_idx(inode, bindex);
+		if (unlikely(!lower_inode))
+			continue;
+		pr_debug("IT(%lu:%d): %s:%s:%d "
+			 "um=%lu/%lu lm=%lu/%lu uc=%lu/%lu lc=%lu/%lu\n",
+			 inode->i_ino, bindex,
+			 file, fxn, line,
+			 inode->i_mtime.tv_sec, inode->i_mtime.tv_nsec,
+			 lower_inode->i_mtime.tv_sec,
+			 lower_inode->i_mtime.tv_nsec,
+			 inode->i_ctime.tv_sec, inode->i_ctime.tv_nsec,
+			 lower_inode->i_ctime.tv_sec,
+			 lower_inode->i_ctime.tv_nsec);
+	}
+}
+
+void __show_dinode_times(const struct dentry *dentry,
+			const char *file, const char *fxn, int line)
+{
+	struct inode *inode = dentry->d_inode;
+	struct inode *lower_inode;
+	int bindex;
+
+	for (bindex = ibstart(inode); bindex <= ibend(inode); bindex++) {
+		lower_inode = unionfs_lower_inode_idx(inode, bindex);
+		if (!lower_inode)
+			continue;
+		pr_debug("DT(%s:%lu:%d): %s:%s:%d "
+			 "um=%lu/%lu lm=%lu/%lu uc=%lu/%lu lc=%lu/%lu\n",
+			 dentry->d_name.name, inode->i_ino, bindex,
+			 file, fxn, line,
+			 inode->i_mtime.tv_sec, inode->i_mtime.tv_nsec,
+			 lower_inode->i_mtime.tv_sec,
+			 lower_inode->i_mtime.tv_nsec,
+			 inode->i_ctime.tv_sec, inode->i_ctime.tv_nsec,
+			 lower_inode->i_ctime.tv_sec,
+			 lower_inode->i_ctime.tv_nsec);
+	}
+}
+
+void __show_inode_counts(const struct inode *inode,
+			const char *file, const char *fxn, int line)
+{
+	struct inode *lower_inode;
+	int bindex;
+
+	if (unlikely(!inode)) {
+		pr_debug("SiC: Null inode\n");
+		return;
+	}
+	for (bindex = sbstart(inode->i_sb); bindex <= sbend(inode->i_sb);
+	     bindex++) {
+		lower_inode = unionfs_lower_inode_idx(inode, bindex);
+		if (unlikely(!lower_inode))
+			continue;
+		pr_debug("SIC(%lu:%d:%d): lc=%d %s:%s:%d\n",
+			 inode->i_ino, bindex,
+			 atomic_read(&(inode)->i_count),
+			 atomic_read(&(lower_inode)->i_count),
+			 file, fxn, line);
+	}
+}
-- 
1.5.2.2

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