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authorArtem Bityutskiy <Artem.Bityutskiy@linux.intel.com>2012-07-14 14:19:46 +0300
committerArtem Bityutskiy <artem.bityutskiy@linux.intel.com>2012-07-20 10:27:25 +0300
commit06bef9451a4c5ad882cd15fd7a0df9890c0249f3 (patch)
treeabd269a573e5ffce8b7e92c39cc3000ca1ecb944 /fs/ubifs/debug.c
parent782759b9f5f5223e0962af60c3457c912fab755f (diff)
downloadlinux-06bef9451a4c5ad882cd15fd7a0df9890c0249f3.tar.gz
UBIFS: add debugfs knob to switch to R/O mode
This patch adds another debugfs knob which switches UBIFS to R/O mode.
I needed it while trying to reproduce the 'first log node is not CS node'
bug. Without this debugfs knob you have to perform a power cut to repruduce
the bug. The knob is named 'ro_error' and all it does is it sets the
'ro_error' UBIFS flag which makes UBIFS disallow any further writes - even
write-back will fail with -EROFS. Useful for debugging.

Signed-off-by: Artem Bityutskiy <Artem.Bityutskiy@linux.intel.com>
Diffstat (limited to 'fs/ubifs/debug.c')
-rw-r--r--fs/ubifs/debug.c11
1 files changed, 11 insertions, 0 deletions
diff --git a/fs/ubifs/debug.c b/fs/ubifs/debug.c
index 92df3b081539..bb3167257aab 100644
--- a/fs/ubifs/debug.c
+++ b/fs/ubifs/debug.c
@@ -2802,6 +2802,8 @@ static ssize_t dfs_file_read(struct file *file, char __user *u, size_t count,
 		val = d->chk_fs;
 	else if (dent == d->dfs_tst_rcvry)
 		val = d->tst_rcvry;
+	else if (dent == d->dfs_ro_error)
+		val = c->ro_error;
 	else
 		return -EINVAL;
 
@@ -2885,6 +2887,8 @@ static ssize_t dfs_file_write(struct file *file, const char __user *u,
 		d->chk_fs = val;
 	else if (dent == d->dfs_tst_rcvry)
 		d->tst_rcvry = val;
+	else if (dent == d->dfs_ro_error)
+		c->ro_error = !!val;
 	else
 		return -EINVAL;
 
@@ -2996,6 +3000,13 @@ int dbg_debugfs_init_fs(struct ubifs_info *c)
 		goto out_remove;
 	d->dfs_tst_rcvry = dent;
 
+	fname = "ro_error";
+	dent = debugfs_create_file(fname, S_IRUSR | S_IWUSR, d->dfs_dir, c,
+				   &dfs_fops);
+	if (IS_ERR_OR_NULL(dent))
+		goto out_remove;
+	d->dfs_ro_error = dent;
+
 	return 0;
 
 out_remove: