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Btrfs: Fix hole insertion corner cases
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There were a few places that could cause duplicate extent insertion,
this adjusts the code that creates holes to avoid it.

lookup_extent_map is changed to correctly return all of the extents in a
range, even when there are none matching at the start of the range.

Signed-off-by: Chris Mason <chris.mason@oracle.com>
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Chris Mason committed Sep 25, 2008
1 parent c1e32da commit 5f56406
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Showing 4 changed files with 126 additions and 13 deletions.
1 change: 1 addition & 0 deletions fs/btrfs/ctree.h
View file
Original file line number Diff line number Diff line change
Expand Up @@ -1170,6 +1170,7 @@ int btrfs_update_inode(struct btrfs_trans_handle *trans,
struct inode *inode);
/* file.c */
int btrfs_drop_extent_cache(struct inode *inode, u64 start, u64 end);
int btrfs_check_file(struct btrfs_root *root, struct inode *inode);
extern struct file_operations btrfs_file_operations;
int btrfs_drop_extents(struct btrfs_trans_handle *trans,
struct btrfs_root *root, struct inode *inode,
Expand Down
45 changes: 36 additions & 9 deletions fs/btrfs/extent_map.c
View file
Original file line number Diff line number Diff line change
Expand Up @@ -204,10 +204,12 @@ static struct rb_node *tree_insert(struct rb_root *root, u64 offset,
}

static struct rb_node *__tree_search(struct rb_root *root, u64 offset,
struct rb_node **prev_ret)
struct rb_node **prev_ret,
struct rb_node **next_ret)
{
struct rb_node * n = root->rb_node;
struct rb_node *prev = NULL;
struct rb_node *orig_prev = NULL;
struct tree_entry *entry;
struct tree_entry *prev_entry = NULL;

Expand All @@ -223,21 +225,33 @@ static struct rb_node *__tree_search(struct rb_root *root, u64 offset,
else
return n;
}
if (!prev_ret)
return NULL;
while(prev && offset > prev_entry->end) {
prev = rb_next(prev);

if (prev_ret) {
orig_prev = prev;
while(prev && offset > prev_entry->end) {
prev = rb_next(prev);
prev_entry = rb_entry(prev, struct tree_entry, rb_node);
}
*prev_ret = prev;
prev = orig_prev;
}

if (next_ret) {
prev_entry = rb_entry(prev, struct tree_entry, rb_node);
while(prev && offset < prev_entry->start) {
prev = rb_prev(prev);
prev_entry = rb_entry(prev, struct tree_entry, rb_node);
}
*next_ret = prev;
}
*prev_ret = prev;
return NULL;
}

static inline struct rb_node *tree_search(struct rb_root *root, u64 offset)
{
struct rb_node *prev;
struct rb_node *ret;
ret = __tree_search(root, offset, &prev);
ret = __tree_search(root, offset, &prev, NULL);
if (!ret)
return prev;
return ret;
Expand All @@ -248,7 +262,7 @@ static int tree_delete(struct rb_root *root, u64 offset)
struct rb_node *node;
struct tree_entry *entry;

node = __tree_search(root, offset, NULL);
node = __tree_search(root, offset, NULL, NULL);
if (!node)
return -ENOENT;
entry = rb_entry(node, struct tree_entry, rb_node);
Expand Down Expand Up @@ -314,9 +328,21 @@ struct extent_map *lookup_extent_mapping(struct extent_map_tree *tree,
{
struct extent_map *em;
struct rb_node *rb_node;
struct rb_node *prev = NULL;
struct rb_node *next = NULL;

read_lock_irq(&tree->lock);
rb_node = tree_search(&tree->map, start);
rb_node = __tree_search(&tree->map, start, &prev, &next);
if (!rb_node && prev) {
em = rb_entry(prev, struct extent_map, rb_node);
if (em->start <= end && em->end >= start)
goto found;
}
if (!rb_node && next) {
em = rb_entry(next, struct extent_map, rb_node);
if (em->start <= end && em->end >= start)
goto found;
}
if (!rb_node) {
em = NULL;
goto out;
Expand All @@ -330,6 +356,7 @@ struct extent_map *lookup_extent_mapping(struct extent_map_tree *tree,
em = NULL;
goto out;
}
found:
atomic_inc(&em->refs);
out:
read_unlock_irq(&tree->lock);
Expand Down
78 changes: 77 additions & 1 deletion fs/btrfs/file.c
View file
Original file line number Diff line number Diff line change
Expand Up @@ -278,7 +278,7 @@ static int noinline dirty_and_release_pages(struct btrfs_trans_handle *trans,
u64 hole_size;
u64 mask = root->sectorsize - 1;
last_pos_in_file = (isize + mask) & ~mask;
hole_size = (start_pos - last_pos_in_file + mask) & ~mask;
hole_size = (end_pos - last_pos_in_file + mask) & ~mask;

if (last_pos_in_file < start_pos) {
err = btrfs_drop_extents(trans, root, inode,
Expand All @@ -293,6 +293,7 @@ static int noinline dirty_and_release_pages(struct btrfs_trans_handle *trans,
inode->i_ino,
last_pos_in_file,
0, 0, hole_size);
btrfs_check_file(root, inode);
}
if (err)
goto failed;
Expand Down Expand Up @@ -378,6 +379,80 @@ int btrfs_drop_extent_cache(struct inode *inode, u64 start, u64 end)
return 0;
}

int btrfs_check_file(struct btrfs_root *root, struct inode *inode)
{
return 0;
#if 0
struct btrfs_path *path;
struct btrfs_key found_key;
struct extent_buffer *leaf;
struct btrfs_file_extent_item *extent;
u64 last_offset = 0;
int nritems;
int slot;
int found_type;
int ret;
int err = 0;
u64 extent_end = 0;

path = btrfs_alloc_path();
ret = btrfs_lookup_file_extent(NULL, root, path, inode->i_ino,
last_offset, 0);
while(1) {
nritems = btrfs_header_nritems(path->nodes[0]);
if (path->slots[0] >= nritems) {
ret = btrfs_next_leaf(root, path);
if (ret)
goto out;
nritems = btrfs_header_nritems(path->nodes[0]);
}
slot = path->slots[0];
leaf = path->nodes[0];
btrfs_item_key_to_cpu(leaf, &found_key, slot);
if (found_key.objectid != inode->i_ino)
break;
if (found_key.type != BTRFS_EXTENT_DATA_KEY)
goto out;

if (found_key.offset != last_offset) {
WARN_ON(1);
btrfs_print_leaf(root, leaf);
printk("inode %lu found offset %Lu expected %Lu\n",
inode->i_ino, found_key.offset, last_offset);
err = 1;
goto out;
}
extent = btrfs_item_ptr(leaf, slot,
struct btrfs_file_extent_item);
found_type = btrfs_file_extent_type(leaf, extent);
if (found_type == BTRFS_FILE_EXTENT_REG) {
extent_end = found_key.offset +
btrfs_file_extent_num_bytes(leaf, extent);
} else if (found_type == BTRFS_FILE_EXTENT_INLINE) {
struct btrfs_item *item;
item = btrfs_item_nr(leaf, slot);
extent_end = found_key.offset +
btrfs_file_extent_inline_len(leaf, item);
extent_end = (extent_end + root->sectorsize - 1) &
~((u64)root->sectorsize -1 );
}
last_offset = extent_end;
path->slots[0]++;
}
if (last_offset < inode->i_size) {
WARN_ON(1);
btrfs_print_leaf(root, leaf);
printk("inode %lu found offset %Lu size %Lu\n", inode->i_ino,
last_offset, inode->i_size);
err = 1;

}
out:
btrfs_free_path(path);
return err;
#endif
}

/*
* this is very complex, but the basic idea is to drop all extents
* in the range start - end. hint_block is filled in with a block number
Expand Down Expand Up @@ -436,6 +511,7 @@ int btrfs_drop_extents(struct btrfs_trans_handle *trans,
slot = path->slots[0];
ret = 0;
btrfs_item_key_to_cpu(leaf, &key, slot);

if (key.offset >= end || key.objectid != inode->i_ino) {
goto out;
}
Expand Down
15 changes: 12 additions & 3 deletions fs/btrfs/inode.c
View file
Original file line number Diff line number Diff line change
Expand Up @@ -133,6 +133,7 @@ static int cow_file_range(struct inode *inode, u64 start, u64 end)
ret = btrfs_insert_file_extent(trans, root, inode->i_ino,
start, ins.objectid, ins.offset,
ins.offset);
btrfs_check_file(root, inode);
num_bytes -= cur_alloc_size;
alloc_hint = ins.objectid + ins.offset;
start += cur_alloc_size;
Expand Down Expand Up @@ -965,12 +966,18 @@ static int btrfs_setattr(struct dentry *dentry, struct iattr *attr)
u64 mask = root->sectorsize - 1;
u64 pos = (inode->i_size + mask) & ~mask;
u64 block_end = attr->ia_size | mask;
u64 hole_start;
u64 hole_size;
u64 alloc_hint = 0;

if (attr->ia_size <= pos)
goto out;

if (pos != inode->i_size)
hole_start = pos + root->sectorsize;
else
hole_start = pos;

mutex_lock(&root->fs_info->fs_mutex);
err = btrfs_check_free_space(root, 1, 0);
mutex_unlock(&root->fs_info->fs_mutex);
Expand All @@ -980,19 +987,21 @@ static int btrfs_setattr(struct dentry *dentry, struct iattr *attr)
btrfs_truncate_page(inode->i_mapping, inode->i_size);

lock_extent(em_tree, pos, block_end, GFP_NOFS);
hole_size = (attr->ia_size - pos + mask) & ~mask;
hole_size = block_end - hole_start;

mutex_lock(&root->fs_info->fs_mutex);
trans = btrfs_start_transaction(root, 1);
btrfs_set_trans_block_group(trans, inode);
err = btrfs_drop_extents(trans, root, inode,
pos, pos + hole_size, pos,
pos, block_end, pos,
&alloc_hint);

if (alloc_hint != EXTENT_MAP_INLINE) {
err = btrfs_insert_file_extent(trans, root,
inode->i_ino,
pos, 0, 0, hole_size);
hole_start, 0, 0,
hole_size);
btrfs_check_file(root, inode);
}
btrfs_end_transaction(trans, root);
mutex_unlock(&root->fs_info->fs_mutex);
Expand Down

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