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staging: erofs: harden inode lookup for 32-bit platforms

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This patch introduces inode hash function, test and set callbacks,
and iget5_locked to find the right inode for 32-bit platforms.

Reviewed-by: Chao Yu <yuchao0@huawei.com>
Signed-off-by: Gao Xiang <gaoxiang25@huawei.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
This commit is contained in:
Gao Xiang 2018-10-09 22:07:13 +08:00 committed by Greg Kroah-Hartman
parent 10844575cc
commit 2abd781413
2 changed files with 45 additions and 1 deletions
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37
drivers/staging/erofs/inode.c
View file

@ -232,10 +232,45 @@ static int fill_inode(struct inode *inode, int isdir)
return err;
}
/*
* erofs nid is 64bits, but i_ino is 'unsigned long', therefore
* we should do more for 32-bit platform to find the right inode.
*/
#if BITS_PER_LONG == 32
static int erofs_ilookup_test_actor(struct inode *inode, void *opaque)
{
const erofs_nid_t nid = *(erofs_nid_t *)opaque;
return EROFS_V(inode)->nid == nid;
}
static int erofs_iget_set_actor(struct inode *inode, void *opaque)
{
const erofs_nid_t nid = *(erofs_nid_t *)opaque;
inode->i_ino = erofs_inode_hash(nid);
return 0;
}
#endif
static inline struct inode *erofs_iget_locked(struct super_block *sb,
erofs_nid_t nid)
{
const unsigned long hashval = erofs_inode_hash(nid);
#if BITS_PER_LONG >= 64
/* it is safe to use iget_locked for >= 64-bit platform */
return iget_locked(sb, hashval);
#else
return iget5_locked(sb, hashval, erofs_ilookup_test_actor,
erofs_iget_set_actor, &nid);
#endif
}
struct inode *erofs_iget(struct super_block *sb,
erofs_nid_t nid, bool isdir)
{
struct inode *inode = iget_locked(sb, nid);
struct inode *inode = erofs_iget_locked(sb, nid);
if (unlikely(inode == NULL))
return ERR_PTR(-ENOMEM);

9
drivers/staging/erofs/internal.h
View file

@ -517,6 +517,15 @@ erofs_get_inline_page(struct inode *inode,
}
/* inode.c */
static inline unsigned long erofs_inode_hash(erofs_nid_t nid)
{
#if BITS_PER_LONG == 32
return (nid >> 32) ^ (nid & 0xffffffff);
#else
return nid;
#endif
}
extern struct inode *erofs_iget(struct super_block *sb,
erofs_nid_t nid, bool dir);