JFFS2 locking regression fix.

Commit a491486a2087ac3dfc00efb4f838c8d684afaf54 introduced a locking
problem in JFFS2 -- we up() the alloc_sem when we weren't previously
holding it. This leads to all kinds of fun behaviour later.

There was a _reason_ for the
	if (1 /* alternative path needs testing */ ||
which the above-mentioned commit removed :)

Discovered and debugged by Giulio Fedel <giulio.fedel@andorsystems.com>

Signed-off-by: David Woodhouse <dwmw2@infradead.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

1 files changed, 3 insertions, 0 deletions

diff --git a/fs/jffs2/write.c b/fs/jffs2/write.c
index bc6185933664..664c164aa67c 100644
--- a/fs/jffs2/write.c
+++ b/fs/jffs2/write.c
@@ -566,6 +566,9 @@ int jffs2_do_unlink(struct jffs2_sb_info *c, struct jffs2_inode_info *dir_f,
                 struct jffs2_full_dirent **prev = &dir_f->dents;
                 uint32_t nhash = full_name_hash(name, namelen);
 
+                /* We don't actually want to reserve any space, but we do
+                   want to be holding the alloc_sem when we write to flash */
+                down(&c->alloc_sem);
                 down(&dir_f->sem);
 
                 while ((*prev) && (*prev)->nhash <= nhash) {