jffs2: fix unbalanced locking
Li Zefan reported an unbalanced locking issue, found by his
internal debugging feature on runtime. The particular case he was
looking at doesn't lead to a deadlock, as the structure that this lock
is embedded in is freed on error. But we should straighten out the error
handling.
Because several callers of jffs2_do_read_inode_internal() /
jffs2_do_read_inode() already handle the locking/unlocking and inode
clearing at their own level, let's just push any unlocks/clearing down
to the caller. This consistency is much easier to verify.
Reported-by: Li Zefan <lizefan@huawei.com>
Cc: David Woodhouse <dwmw2@infradead.org>
Cc: Artem Bityutskiy <artem.bityutskiy@linux.intel.com>
Cc: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Brian Norris <computersforpeace@gmail.com>
diff --git a/fs/jffs2/fs.c b/fs/jffs2/fs.c
index fe5ea08..4cff0d5 100644
--- a/fs/jffs2/fs.c
+++ b/fs/jffs2/fs.c
@@ -272,12 +272,9 @@
mutex_lock(&f->sem);
ret = jffs2_do_read_inode(c, f, inode->i_ino, &latest_node);
+ if (ret)
+ goto error;
- if (ret) {
- mutex_unlock(&f->sem);
- iget_failed(inode);
- return ERR_PTR(ret);
- }
inode->i_mode = jemode_to_cpu(latest_node.mode);
i_uid_write(inode, je16_to_cpu(latest_node.uid));
i_gid_write(inode, je16_to_cpu(latest_node.gid));
diff --git a/fs/jffs2/readinode.c b/fs/jffs2/readinode.c
index dddbde4..28e0aab 100644
--- a/fs/jffs2/readinode.c
+++ b/fs/jffs2/readinode.c
@@ -1203,17 +1203,13 @@
JFFS2_ERROR("failed to read from flash: error %d, %zd of %zd bytes read\n",
ret, retlen, sizeof(*latest_node));
/* FIXME: If this fails, there seems to be a memory leak. Find it. */
- mutex_unlock(&f->sem);
- jffs2_do_clear_inode(c, f);
- return ret?ret:-EIO;
+ return ret ? ret : -EIO;
}
crc = crc32(0, latest_node, sizeof(*latest_node)-8);
if (crc != je32_to_cpu(latest_node->node_crc)) {
JFFS2_ERROR("CRC failed for read_inode of inode %u at physical location 0x%x\n",
f->inocache->ino, ref_offset(rii.latest_ref));
- mutex_unlock(&f->sem);
- jffs2_do_clear_inode(c, f);
return -EIO;
}
@@ -1250,16 +1246,11 @@
* keep in RAM to facilitate quick follow symlink
* operation. */
uint32_t csize = je32_to_cpu(latest_node->csize);
- if (csize > JFFS2_MAX_NAME_LEN) {
- mutex_unlock(&f->sem);
- jffs2_do_clear_inode(c, f);
+ if (csize > JFFS2_MAX_NAME_LEN)
return -ENAMETOOLONG;
- }
f->target = kmalloc(csize + 1, GFP_KERNEL);
if (!f->target) {
JFFS2_ERROR("can't allocate %u bytes of memory for the symlink target path cache\n", csize);
- mutex_unlock(&f->sem);
- jffs2_do_clear_inode(c, f);
return -ENOMEM;
}
@@ -1271,8 +1262,6 @@
ret = -EIO;
kfree(f->target);
f->target = NULL;
- mutex_unlock(&f->sem);
- jffs2_do_clear_inode(c, f);
return ret;
}
@@ -1289,15 +1278,11 @@
if (f->metadata) {
JFFS2_ERROR("Argh. Special inode #%u with mode 0%o had metadata node\n",
f->inocache->ino, jemode_to_cpu(latest_node->mode));
- mutex_unlock(&f->sem);
- jffs2_do_clear_inode(c, f);
return -EIO;
}
if (!frag_first(&f->fragtree)) {
JFFS2_ERROR("Argh. Special inode #%u with mode 0%o has no fragments\n",
f->inocache->ino, jemode_to_cpu(latest_node->mode));
- mutex_unlock(&f->sem);
- jffs2_do_clear_inode(c, f);
return -EIO;
}
/* ASSERT: f->fraglist != NULL */
@@ -1305,8 +1290,6 @@
JFFS2_ERROR("Argh. Special inode #%u with mode 0x%x had more than one node\n",
f->inocache->ino, jemode_to_cpu(latest_node->mode));
/* FIXME: Deal with it - check crc32, check for duplicate node, check times and discard the older one */
- mutex_unlock(&f->sem);
- jffs2_do_clear_inode(c, f);
return -EIO;
}
/* OK. We're happy */
@@ -1400,10 +1383,8 @@
f->inocache = ic;
ret = jffs2_do_read_inode_internal(c, f, &n);
- if (!ret) {
- mutex_unlock(&f->sem);
- jffs2_do_clear_inode(c, f);
- }
+ mutex_unlock(&f->sem);
+ jffs2_do_clear_inode(c, f);
jffs2_xattr_do_crccheck_inode(c, ic);
kfree (f);
return ret;