ref: d6816b4c0d80b8068b22db6161ec660506ad58d7
parent: 61098c719f30316c4bac054170c262d0419849a9
author: Kaho Ng <ngkaho1234@gmail.com>
date: Sun May 15 20:16:37 EDT 2016
ext4_xattr: better handling on some corner error case
--- a/include/ext4_xattr.h
+++ b/include/ext4_xattr.h
@@ -50,6 +50,7 @@
struct ext4_xattr_item {/* This attribute should be stored in inode body */
bool in_inode;
+ bool is_data;
uint8_t name_index;
char *name;
@@ -66,6 +67,8 @@
struct ext4_inode_ref *inode_ref;
bool dirty;
size_t ea_size;
+ int32_t block_size_rem;
+ int32_t inode_size_rem;
struct ext4_fs *fs;
void *iter_arg;
--- a/src/ext4_xattr.c
+++ b/src/ext4_xattr.c
@@ -167,10 +167,10 @@
struct ext4_xattr_item *b)
{int result;
- if (a->in_inode && !b->in_inode)
+ if (a->is_data && !b->is_data)
return -1;
- if (!a->in_inode && b->in_inode)
+ if (!a->is_data && b->is_data)
return 1;
result = a->name_index - b->name_index;
@@ -200,6 +200,7 @@
item->name_len = name_len;
item->data = NULL;
item->data_size = 0;
+ item->in_inode = false;
memset(&item->node, 0, sizeof(item->node));
memcpy(item->name, name, name_len);
@@ -207,9 +208,9 @@
if (name_index == EXT4_XATTR_INDEX_SYSTEM &&
name_len == 4 &&
!memcmp(name, "data", 4))
- item->in_inode = true;
+ item->is_data = true;
else
- item->in_inode = false;
+ item->is_data = false;
return item;
}
@@ -328,6 +329,9 @@
goto Finish;
}
RB_INSERT(ext4_xattr_tree, &xattr_ref->root, item);
+ xattr_ref->block_size_rem -=
+ EXT4_XATTR_SIZE(item->data_size) +
+ EXT4_XATTR_LEN(item->name_len);
xattr_ref->ea_size += EXT4_XATTR_SIZE(item->data_size) +
EXT4_XATTR_LEN(item->name_len);
}
@@ -377,7 +381,11 @@
ret = ENOMEM;
goto Finish;
}
+ item->in_inode = true;
RB_INSERT(ext4_xattr_tree, &xattr_ref->root, item);
+ xattr_ref->inode_size_rem -=
+ EXT4_XATTR_SIZE(item->data_size) +
+ EXT4_XATTR_LEN(item->name_len);
xattr_ref->ea_size += EXT4_XATTR_SIZE(item->data_size) +
EXT4_XATTR_LEN(item->name_len);
}
@@ -430,7 +438,7 @@
if (name_index == EXT4_XATTR_INDEX_SYSTEM &&
name_len == 4 &&
!memcmp(name, "data", 4))
- tmp.in_inode = true;
+ tmp.is_data = true;
return RB_FIND(ext4_xattr_tree, &xattr_ref->root, &tmp);
}
@@ -459,6 +467,17 @@
return NULL;
}
+ item->in_inode = true;
+ if (xattr_ref->inode_size_rem -
+ (int32_t)EXT4_XATTR_SIZE(data_size) -
+ (int32_t)EXT4_XATTR_LEN(item->name_len) < 0) {+ if (xattr_ref->block_size_rem -
+ (int32_t)EXT4_XATTR_SIZE(data_size) -
+ (int32_t)EXT4_XATTR_LEN(item->name_len) < 0)
+ return NULL;
+
+ item->in_inode = false;
+ }
if (ext4_xattr_item_alloc_data(item, data, data_size) != EOK) {ext4_xattr_item_free(item);
return NULL;
@@ -466,6 +485,15 @@
RB_INSERT(ext4_xattr_tree, &xattr_ref->root, item);
xattr_ref->ea_size +=
EXT4_XATTR_SIZE(item->data_size) + EXT4_XATTR_LEN(item->name_len);
+ if (item->in_inode) {+ xattr_ref->inode_size_rem -=
+ EXT4_XATTR_SIZE(item->data_size) +
+ EXT4_XATTR_LEN(item->name_len);
+ } else {+ xattr_ref->block_size_rem -=
+ EXT4_XATTR_SIZE(item->data_size) +
+ EXT4_XATTR_LEN(item->name_len);
+ }
xattr_ref->dirty = true;
return item;
}
@@ -485,6 +513,16 @@
xattr_ref->ea_size -= EXT4_XATTR_SIZE(item->data_size) +
EXT4_XATTR_LEN(item->name_len);
+ if (item->in_inode) {+ xattr_ref->inode_size_rem +=
+ EXT4_XATTR_SIZE(item->data_size) +
+ EXT4_XATTR_LEN(item->name_len);
+ } else {+ xattr_ref->block_size_rem +=
+ EXT4_XATTR_SIZE(item->data_size) +
+ EXT4_XATTR_LEN(item->name_len);
+ }
+
RB_REMOVE(ext4_xattr_tree, &xattr_ref->root, item);
ext4_xattr_item_free(item);
xattr_ref->dirty = true;
@@ -498,29 +536,103 @@
size_t new_data_size)
{int ret = EOK;
+ bool to_inode = false, to_block = false;
size_t old_data_size = item->data_size;
+ int32_t orig_room_size = item->in_inode ?
+ xattr_ref->inode_size_rem :
+ xattr_ref->block_size_rem;
+
+ /*
+ * Check if we can hold this entry in both in-inode and
+ * on-block form
+ */
if ((xattr_ref->ea_size - EXT4_XATTR_SIZE(old_data_size) +
EXT4_XATTR_SIZE(new_data_size)
>
ext4_xattr_inode_space(xattr_ref) -
- sizeof(struct ext4_xattr_ibody_header))
+ sizeof(struct ext4_xattr_ibody_header))
&&
(xattr_ref->ea_size - EXT4_XATTR_SIZE(old_data_size) +
EXT4_XATTR_SIZE(new_data_size)
>
ext4_xattr_block_space(xattr_ref) -
- sizeof(struct ext4_xattr_header))) {+ sizeof(struct ext4_xattr_header))) {return ENOSPC;
}
+
+ /*
+ * More complicated case: we do not allow entries stucking in
+ * the middle between in-inode space and on-block space, so
+ * the entry has to stay in either inode space or block space.
+ */
+ if (item->in_inode) {+ if (xattr_ref->inode_size_rem +
+ (int32_t)EXT4_XATTR_SIZE(old_data_size) -
+ (int32_t)EXT4_XATTR_SIZE(new_data_size) < 0) {+ if (xattr_ref->block_size_rem -
+ (int32_t)EXT4_XATTR_SIZE(new_data_size) -
+ (int32_t)EXT4_XATTR_LEN(item->name_len) < 0)
+ return ENOSPC;
+
+ to_block = true;
+ }
+ } else {+ if (xattr_ref->block_size_rem +
+ (int32_t)EXT4_XATTR_SIZE(old_data_size) -
+ (int32_t)EXT4_XATTR_SIZE(new_data_size) < 0) {+ if (xattr_ref->inode_size_rem -
+ (int32_t)EXT4_XATTR_SIZE(new_data_size) -
+ (int32_t)EXT4_XATTR_LEN(item->name_len) < 0)
+ return ENOSPC;
+
+ to_inode = true;
+ }
+ }
ret = ext4_xattr_item_resize_data(item, new_data_size);
- if (ret != EOK) {+ if (ret != EOK)
return ret;
- }
+
xattr_ref->ea_size =
xattr_ref->ea_size -
EXT4_XATTR_SIZE(old_data_size) +
EXT4_XATTR_SIZE(new_data_size);
+
+ /*
+ * This entry may originally lie in inode space or block space,
+ * and it is going to be transferred to another place.
+ */
+ if (to_block) {+ xattr_ref->inode_size_rem +=
+ EXT4_XATTR_SIZE(old_data_size) +
+ EXT4_XATTR_LEN(item->name_len);
+ xattr_ref->block_size_rem -=
+ EXT4_XATTR_SIZE(new_data_size) +
+ EXT4_XATTR_LEN(item->name_len);
+ item->in_inode = false;
+ } else if (to_inode) {+ xattr_ref->block_size_rem +=
+ EXT4_XATTR_SIZE(old_data_size) +
+ EXT4_XATTR_LEN(item->name_len);
+ xattr_ref->inode_size_rem -=
+ EXT4_XATTR_SIZE(new_data_size) +
+ EXT4_XATTR_LEN(item->name_len);
+ item->in_inode = true;
+ } else {+ /*
+ * No need to transfer as there is enough space for the entry
+ * to stay in inode space or block space it used to be.
+ */
+ orig_room_size +=
+ EXT4_XATTR_SIZE(old_data_size);
+ orig_room_size -=
+ EXT4_XATTR_SIZE(new_data_size);
+ if (item->in_inode)
+ xattr_ref->inode_size_rem = orig_room_size;
+ else
+ xattr_ref->block_size_rem = orig_room_size;
+
+ }
xattr_ref->dirty = true;
return ret;
}
@@ -528,12 +640,18 @@
static void ext4_xattr_purge_items(struct ext4_xattr_ref *xattr_ref)
{struct ext4_xattr_item *item, *save_item;
- RB_FOREACH_SAFE(item, ext4_xattr_tree, &xattr_ref->root, save_item)
- {+ RB_FOREACH_SAFE(item, ext4_xattr_tree, &xattr_ref->root, save_item) {RB_REMOVE(ext4_xattr_tree, &xattr_ref->root, item);
ext4_xattr_item_free(item);
}
xattr_ref->ea_size = 0;
+ xattr_ref->inode_size_rem = ext4_xattr_inode_space(xattr_ref) -
+ sizeof(struct ext4_xattr_ibody_header);
+ if (xattr_ref->inode_size_rem < 0)
+ xattr_ref->inode_size_rem = 0;
+
+ xattr_ref->block_size_rem = ext4_xattr_block_space(xattr_ref) -
+ sizeof(struct ext4_xattr_header);
}
static int ext4_xattr_try_alloc_block(struct ext4_xattr_ref *xattr_ref)
@@ -715,7 +833,8 @@
EXT4_XATTR_LEN(item->name_len) >
block_size_rem) {ret = ENOSPC;
- goto Finish;
+ ext4_dbg(DEBUG_XATTR, "IMPOSSIBLE ENOSPC AS WE DID INSPECTION!\n");
+ ext4_assert(0);
}
block_data =
(char *)block_data - EXT4_XATTR_SIZE(item->data_size);
@@ -859,6 +978,13 @@
ref->inode_ref = inode_ref;
ref->fs = fs;
+ ref->inode_size_rem = ext4_xattr_inode_space(ref) -
+ sizeof(struct ext4_xattr_ibody_header);
+ if (ref->inode_size_rem < 0)
+ ref->inode_size_rem = 0;
+
+ ref->block_size_rem = ext4_xattr_block_space(ref) -
+ sizeof(struct ext4_xattr_header);
rc = ext4_xattr_fetch(ref);
if (rc != EOK) {ext4_xattr_purge_items(ref);