staging: erofs: add error handling for xattr submodule

commit cadf1ccf1b0021d0b7a9347e102ac5258f9f98c8 upstream.

This patch enhances the missing error handling code for
xattr submodule, which improves the stability for the rare cases.

Reviewed-by: Chao Yu <yuchao0@huawei.com>
Signed-off-by: Chao Yu <yuchao0@huawei.com>
Signed-off-by: Gao Xiang <gaoxiang25@huawei.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

diff --git a/drivers/staging/erofs/internal.h b/drivers/staging/erofs/internal.h
index 9f44ed8..1c048c4 100644 (file)
--- a/drivers/staging/erofs/internal.h
+++ b/drivers/staging/erofs/internal.h
@@ -485,8 +485,9 @@ struct erofs_map_blocks_iter {
 };
 
 
-static inline struct page *erofs_get_inline_page(struct inode *inode,
-       erofs_blk_t blkaddr)
+static inline struct page *
+erofs_get_inline_page(struct inode *inode,
+                     erofs_blk_t blkaddr)
 {
        return erofs_get_meta_page(inode->i_sb,
                blkaddr, S_ISDIR(inode->i_mode));

diff --git a/drivers/staging/erofs/xattr.c b/drivers/staging/erofs/xattr.c
index 0e9cfec..9870f89 100644 (file)
--- a/drivers/staging/erofs/xattr.c
+++ b/drivers/staging/erofs/xattr.c
@@ -24,16 +24,25 @@ struct xattr_iter {
 
 static inline void xattr_iter_end(struct xattr_iter *it, bool atomic)
 {
-       /* only init_inode_xattrs use non-atomic once */
+       /* the only user of kunmap() is 'init_inode_xattrs' */
        if (unlikely(!atomic))
                kunmap(it->page);
        else
                kunmap_atomic(it->kaddr);
+
        unlock_page(it->page);
        put_page(it->page);
 }
 
-static void init_inode_xattrs(struct inode *inode)
+static inline void xattr_iter_end_final(struct xattr_iter *it)
+{
+       if (!it->page)
+               return;
+
+       xattr_iter_end(it, true);
+}
+
+static int init_inode_xattrs(struct inode *inode)
 {
        struct xattr_iter it;
        unsigned i;
@@ -43,7 +52,7 @@ static void init_inode_xattrs(struct inode *inode)
        bool atomic_map;
 
        if (likely(inode_has_inited_xattr(inode)))
-               return;
+               return 0;
 
        vi = EROFS_V(inode);
        BUG_ON(!vi->xattr_isize);
@@ -53,7 +62,8 @@ static void init_inode_xattrs(struct inode *inode)
        it.ofs = erofs_blkoff(iloc(sbi, vi->nid) + vi->inode_isize);
 
        it.page = erofs_get_inline_page(inode, it.blkaddr);
-       BUG_ON(IS_ERR(it.page));
+       if (IS_ERR(it.page))
+               return PTR_ERR(it.page);
 
        /* read in shared xattr array (non-atomic, see kmalloc below) */
        it.kaddr = kmap(it.page);
@@ -62,9 +72,12 @@ static void init_inode_xattrs(struct inode *inode)
        ih = (struct erofs_xattr_ibody_header *)(it.kaddr + it.ofs);
 
        vi->xattr_shared_count = ih->h_shared_count;
-       vi->xattr_shared_xattrs = (unsigned *)kmalloc_array(
-               vi->xattr_shared_count, sizeof(unsigned),
-               GFP_KERNEL | __GFP_NOFAIL);
+       vi->xattr_shared_xattrs = kmalloc_array(vi->xattr_shared_count,
+                                               sizeof(uint), GFP_KERNEL);
+       if (!vi->xattr_shared_xattrs) {
+               xattr_iter_end(&it, atomic_map);
+               return -ENOMEM;
+       }
 
        /* let's skip ibody header */
        it.ofs += sizeof(struct erofs_xattr_ibody_header);
@@ -77,7 +90,8 @@ static void init_inode_xattrs(struct inode *inode)
 
                        it.page = erofs_get_meta_page(inode->i_sb,
                                ++it.blkaddr, S_ISDIR(inode->i_mode));
-                       BUG_ON(IS_ERR(it.page));
+                       if (IS_ERR(it.page))
+                               return PTR_ERR(it.page);
 
                        it.kaddr = kmap_atomic(it.page);
                        atomic_map = true;
@@ -90,6 +104,7 @@ static void init_inode_xattrs(struct inode *inode)
        xattr_iter_end(&it, atomic_map);
 
        inode_set_inited_xattr(inode);
+       return 0;
 }
 
 struct xattr_iter_handlers {
@@ -99,18 +114,25 @@ struct xattr_iter_handlers {
        void (*value)(struct xattr_iter *, unsigned, char *, unsigned);
 };
 
-static void xattr_iter_fixup(struct xattr_iter *it)
+static inline int xattr_iter_fixup(struct xattr_iter *it)
 {
-       if (unlikely(it->ofs >= EROFS_BLKSIZ)) {
-               xattr_iter_end(it, true);
+       if (it->ofs < EROFS_BLKSIZ)
+               return 0;
 
-               it->blkaddr += erofs_blknr(it->ofs);
-               it->page = erofs_get_meta_page(it->sb, it->blkaddr, false);
-               BUG_ON(IS_ERR(it->page));
+       xattr_iter_end(it, true);
 
-               it->kaddr = kmap_atomic(it->page);
-               it->ofs = erofs_blkoff(it->ofs);
+       it->blkaddr += erofs_blknr(it->ofs);
+       it->page = erofs_get_meta_page(it->sb, it->blkaddr, false);
+       if (IS_ERR(it->page)) {
+               int err = PTR_ERR(it->page);
+
+               it->page = NULL;
+               return err;
        }
+
+       it->kaddr = kmap_atomic(it->page);
+       it->ofs = erofs_blkoff(it->ofs);
+       return 0;
 }
 
 static int inline_xattr_iter_begin(struct xattr_iter *it,
@@ -132,21 +154,24 @@ static int inline_xattr_iter_begin(struct xattr_iter *it,
        it->ofs = erofs_blkoff(iloc(sbi, vi->nid) + inline_xattr_ofs);
 
        it->page = erofs_get_inline_page(inode, it->blkaddr);
-       BUG_ON(IS_ERR(it->page));
-       it->kaddr = kmap_atomic(it->page);
+       if (IS_ERR(it->page))
+               return PTR_ERR(it->page);
 
+       it->kaddr = kmap_atomic(it->page);
        return vi->xattr_isize - xattr_header_sz;
 }
 
 static int xattr_foreach(struct xattr_iter *it,
-       struct xattr_iter_handlers *op, unsigned *tlimit)
+       const struct xattr_iter_handlers *op, unsigned int *tlimit)
 {
        struct erofs_xattr_entry entry;
        unsigned value_sz, processed, slice;
        int err;
 
        /* 0. fixup blkaddr, ofs, ipage */
-       xattr_iter_fixup(it);
+       err = xattr_iter_fixup(it);
+       if (err)
+               return err;
 
        /*
         * 1. read xattr entry to the memory,
@@ -178,7 +203,9 @@ static int xattr_foreach(struct xattr_iter *it,
                if (it->ofs >= EROFS_BLKSIZ) {
                        BUG_ON(it->ofs > EROFS_BLKSIZ);
 
-                       xattr_iter_fixup(it);
+                       err = xattr_iter_fixup(it);
+                       if (err)
+                               goto out;
                        it->ofs = 0;
                }
 
@@ -210,7 +237,10 @@ static int xattr_foreach(struct xattr_iter *it,
        while (processed < value_sz) {
                if (it->ofs >= EROFS_BLKSIZ) {
                        BUG_ON(it->ofs > EROFS_BLKSIZ);
-                       xattr_iter_fixup(it);
+
+                       err = xattr_iter_fixup(it);
+                       if (err)
+                               goto out;
                        it->ofs = 0;
                }
 
@@ -270,7 +300,7 @@ static void xattr_copyvalue(struct xattr_iter *_it,
        memcpy(it->buffer + processed, buf, len);
 }
 
-static struct xattr_iter_handlers find_xattr_handlers = {
+static const struct xattr_iter_handlers find_xattr_handlers = {
        .entry = xattr_entrymatch,
        .name = xattr_namematch,
        .alloc_buffer = xattr_checkbuffer,
@@ -291,8 +321,11 @@ static int inline_getxattr(struct inode *inode, struct getxattr_iter *it)
                ret = xattr_foreach(&it->it, &find_xattr_handlers, &remaining);
                if (ret >= 0)
                        break;
+
+               if (ret != -ENOATTR)    /* -ENOMEM, -EIO, etc. */
+                       break;
        }
-       xattr_iter_end(&it->it, true);
+       xattr_iter_end_final(&it->it);
 
        return ret < 0 ? ret : it->buffer_size;
 }
@@ -315,8 +348,10 @@ static int shared_getxattr(struct inode *inode, struct getxattr_iter *it)
                                xattr_iter_end(&it->it, true);
 
                        it->it.page = erofs_get_meta_page(inode->i_sb,
-                               blkaddr, false);
-                       BUG_ON(IS_ERR(it->it.page));
+                                                         blkaddr, false);
+                       if (IS_ERR(it->it.page))
+                               return PTR_ERR(it->it.page);
+
                        it->it.kaddr = kmap_atomic(it->it.page);
                        it->it.blkaddr = blkaddr;
                }
@@ -324,9 +359,12 @@ static int shared_getxattr(struct inode *inode, struct getxattr_iter *it)
                ret = xattr_foreach(&it->it, &find_xattr_handlers, NULL);
                if (ret >= 0)
                        break;
+
+               if (ret != -ENOATTR)    /* -ENOMEM, -EIO, etc. */
+                       break;
        }
        if (vi->xattr_shared_count)
-               xattr_iter_end(&it->it, true);
+               xattr_iter_end_final(&it->it);
 
        return ret < 0 ? ret : it->buffer_size;
 }
@@ -351,7 +389,9 @@ int erofs_getxattr(struct inode *inode, int index,
        if (unlikely(name == NULL))
                return -EINVAL;
 
-       init_inode_xattrs(inode);
+       ret = init_inode_xattrs(inode);
+       if (ret)
+               return ret;
 
        it.index = index;
 
@@ -494,7 +534,7 @@ static int xattr_skipvalue(struct xattr_iter *_it,
        return 1;
 }
 
-static struct xattr_iter_handlers list_xattr_handlers = {
+static const struct xattr_iter_handlers list_xattr_handlers = {
        .entry = xattr_entrylist,
        .name = xattr_namelist,
        .alloc_buffer = xattr_skipvalue,
@@ -516,7 +556,7 @@ static int inline_listxattr(struct listxattr_iter *it)
                if (ret < 0)
                        break;
        }
-       xattr_iter_end(&it->it, true);
+       xattr_iter_end_final(&it->it);
        return ret < 0 ? ret : it->buffer_ofs;
 }
 
@@ -538,8 +578,10 @@ static int shared_listxattr(struct listxattr_iter *it)
                                xattr_iter_end(&it->it, true);
 
                        it->it.page = erofs_get_meta_page(inode->i_sb,
-                               blkaddr, false);
-                       BUG_ON(IS_ERR(it->it.page));
+                                                         blkaddr, false);
+                       if (IS_ERR(it->it.page))
+                               return PTR_ERR(it->it.page);
+
                        it->it.kaddr = kmap_atomic(it->it.page);
                        it->it.blkaddr = blkaddr;
                }
@@ -549,7 +591,7 @@ static int shared_listxattr(struct listxattr_iter *it)
                        break;
        }
        if (vi->xattr_shared_count)
-               xattr_iter_end(&it->it, true);
+               xattr_iter_end_final(&it->it);
 
        return ret < 0 ? ret : it->buffer_ofs;
 }
@@ -560,7 +602,9 @@ ssize_t erofs_listxattr(struct dentry *dentry,
        int ret;
        struct listxattr_iter it;
 
-       init_inode_xattrs(d_inode(dentry));
+       ret = init_inode_xattrs(d_inode(dentry));
+       if (ret)
+               return ret;
 
        it.dentry = dentry;
        it.buffer = buffer;