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jffs2: fix unbalanced locking

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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>
This commit is contained in:
Brian Norris 2014-02-25 18:27:40 -08:00
parent 3094fe121e
commit 7aaea7605c
2 changed files with 6 additions and 28 deletions
Show stats Download patch file Download diff file Expand all files Collapse all files

7
fs/jffs2/fs.c
View file

@ -272,12 +272,9 @@ struct inode *jffs2_iget(struct super_block *sb, unsigned long ino)
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));

27
fs/jffs2/readinode.c
View file

@ -1203,17 +1203,13 @@ static int jffs2_do_read_inode_internal(struct jffs2_sb_info *c,
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 @@ static int jffs2_do_read_inode_internal(struct jffs2_sb_info *c,
* 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 @@ static int jffs2_do_read_inode_internal(struct jffs2_sb_info *c,
ret = -EIO;
kfree(f->target);
f->target = NULL;
mutex_unlock(&f->sem);
jffs2_do_clear_inode(c, f);
return ret;
}
@ -1289,15 +1278,11 @@ static int jffs2_do_read_inode_internal(struct jffs2_sb_info *c,
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 @@ static int jffs2_do_read_inode_internal(struct jffs2_sb_info *c,
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 @@ int jffs2_do_crccheck_inode(struct jffs2_sb_info *c, struct jffs2_inode_cache *i
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;