Btrfs: fix bad extent logging
A user sent me a btrfs-image of a file system that was panicing on mount during
the log recovery. I had originally thought these problems were from a bug in
the free space cache code, but that was just a symptom of the problem. The
problem is if your application does something like this
[prealloc][prealloc][prealloc]
the internal extent maps will merge those all together into one extent map, even
though on disk they are 3 separate extents. So if you go to write into one of
these ranges the extent map will be right since we use the physical extent when
doing the write, but when we log the extents they will use the wrong sizes for
the remainder prealloc space. If this doesn't happen to trip up the free space
cache (which it won't in a lot of cases) then you will get bogus entries in your
extent tree which will screw stuff up later. The data and such will still work,
but everything else is broken. This patch fixes this by not allowing extents
that are on the modified list to be merged. This has the side effect that we
are no longer adding everything to the modified list all the time, which means
we now have to call btrfs_drop_extents every time we log an extent into the
tree. So this allows me to drop all this speciality code I was using to get
around calling btrfs_drop_extents. With this patch the testcase I've created no
longer creates a bogus file system after replaying the log. Thanks,
Signed-off-by: Josef Bacik <jbacik@fusionio.com>
diff --git a/fs/btrfs/ctree.c b/fs/btrfs/ctree.c
index fe032ab..9ca0f6a 100644
--- a/fs/btrfs/ctree.c
+++ b/fs/btrfs/ctree.c
@@ -2211,9 +2211,6 @@
int no_skips = 0;
struct extent_buffer *t;
- if (path->really_keep_locks)
- return;
-
for (i = level; i < BTRFS_MAX_LEVEL; i++) {
if (!path->nodes[i])
break;
@@ -2261,7 +2258,7 @@
{
int i;
- if (path->keep_locks || path->really_keep_locks)
+ if (path->keep_locks)
return;
for (i = level; i < BTRFS_MAX_LEVEL; i++) {
@@ -2494,7 +2491,7 @@
if (!cow)
write_lock_level = -1;
- if (cow && (p->really_keep_locks || p->keep_locks || p->lowest_level))
+ if (cow && (p->keep_locks || p->lowest_level))
write_lock_level = BTRFS_MAX_LEVEL;
min_write_lock_level = write_lock_level;
@@ -5465,139 +5462,6 @@
return btrfs_next_old_leaf(root, path, 0);
}
-/* Release the path up to but not including the given level */
-static void btrfs_release_level(struct btrfs_path *path, int level)
-{
- int i;
-
- for (i = 0; i < level; i++) {
- path->slots[i] = 0;
- if (!path->nodes[i])
- continue;
- if (path->locks[i]) {
- btrfs_tree_unlock_rw(path->nodes[i], path->locks[i]);
- path->locks[i] = 0;
- }
- free_extent_buffer(path->nodes[i]);
- path->nodes[i] = NULL;
- }
-}
-
-/*
- * This function assumes 2 things
- *
- * 1) You are using path->keep_locks
- * 2) You are not inserting items.
- *
- * If either of these are not true do not use this function. If you need a next
- * leaf with either of these not being true then this function can be easily
- * adapted to do that, but at the moment these are the limitations.
- */
-int btrfs_next_leaf_write(struct btrfs_trans_handle *trans,
- struct btrfs_root *root, struct btrfs_path *path,
- int del)
-{
- struct extent_buffer *b;
- struct btrfs_key key;
- u32 nritems;
- int level = 1;
- int slot;
- int ret = 1;
- int write_lock_level = BTRFS_MAX_LEVEL;
- int ins_len = del ? -1 : 0;
-
- WARN_ON(!(path->keep_locks || path->really_keep_locks));
-
- nritems = btrfs_header_nritems(path->nodes[0]);
- btrfs_item_key_to_cpu(path->nodes[0], &key, nritems - 1);
-
- while (path->nodes[level]) {
- nritems = btrfs_header_nritems(path->nodes[level]);
- if (!(path->locks[level] & BTRFS_WRITE_LOCK)) {
-search:
- btrfs_release_path(path);
- ret = btrfs_search_slot(trans, root, &key, path,
- ins_len, 1);
- if (ret < 0)
- goto out;
- level = 1;
- continue;
- }
-
- if (path->slots[level] >= nritems - 1) {
- level++;
- continue;
- }
-
- btrfs_release_level(path, level);
- break;
- }
-
- if (!path->nodes[level]) {
- ret = 1;
- goto out;
- }
-
- path->slots[level]++;
- b = path->nodes[level];
-
- while (b) {
- level = btrfs_header_level(b);
-
- if (!should_cow_block(trans, root, b))
- goto cow_done;
-
- btrfs_set_path_blocking(path);
- ret = btrfs_cow_block(trans, root, b,
- path->nodes[level + 1],
- path->slots[level + 1], &b);
- if (ret)
- goto out;
-cow_done:
- path->nodes[level] = b;
- btrfs_clear_path_blocking(path, NULL, 0);
- if (level != 0) {
- ret = setup_nodes_for_search(trans, root, path, b,
- level, ins_len,
- &write_lock_level);
- if (ret == -EAGAIN)
- goto search;
- if (ret)
- goto out;
-
- b = path->nodes[level];
- slot = path->slots[level];
-
- ret = read_block_for_search(trans, root, path,
- &b, level, slot, &key, 0);
- if (ret == -EAGAIN)
- goto search;
- if (ret)
- goto out;
- level = btrfs_header_level(b);
- if (!btrfs_try_tree_write_lock(b)) {
- btrfs_set_path_blocking(path);
- btrfs_tree_lock(b);
- btrfs_clear_path_blocking(path, b,
- BTRFS_WRITE_LOCK);
- }
- path->locks[level] = BTRFS_WRITE_LOCK;
- path->nodes[level] = b;
- path->slots[level] = 0;
- } else {
- path->slots[level] = 0;
- ret = 0;
- break;
- }
- }
-
-out:
- if (ret)
- btrfs_release_path(path);
-
- return ret;
-}
-
int btrfs_next_old_leaf(struct btrfs_root *root, struct btrfs_path *path,
u64 time_seq)
{
diff --git a/fs/btrfs/ctree.h b/fs/btrfs/ctree.h
index 5060990..075a8a0 100644
--- a/fs/btrfs/ctree.h
+++ b/fs/btrfs/ctree.h
@@ -586,7 +586,6 @@
unsigned int skip_locking:1;
unsigned int leave_spinning:1;
unsigned int search_commit_root:1;
- unsigned int really_keep_locks:1;
};
/*
@@ -3273,9 +3272,6 @@
}
int btrfs_next_leaf(struct btrfs_root *root, struct btrfs_path *path);
-int btrfs_next_leaf_write(struct btrfs_trans_handle *trans,
- struct btrfs_root *root, struct btrfs_path *path,
- int del);
int btrfs_next_old_leaf(struct btrfs_root *root, struct btrfs_path *path,
u64 time_seq);
static inline int btrfs_next_old_item(struct btrfs_root *root,
diff --git a/fs/btrfs/disk-io.c b/fs/btrfs/disk-io.c
index b8ed1d4..70e6b0c 100644
--- a/fs/btrfs/disk-io.c
+++ b/fs/btrfs/disk-io.c
@@ -222,7 +222,7 @@
em->bdev = BTRFS_I(inode)->root->fs_info->fs_devices->latest_bdev;
write_lock(&em_tree->lock);
- ret = add_extent_mapping(em_tree, em);
+ ret = add_extent_mapping(em_tree, em, 0);
if (ret == -EEXIST) {
free_extent_map(em);
em = lookup_extent_mapping(em_tree, start, len);
diff --git a/fs/btrfs/extent_map.c b/fs/btrfs/extent_map.c
index 2834ca57..ca96874 100644
--- a/fs/btrfs/extent_map.c
+++ b/fs/btrfs/extent_map.c
@@ -174,6 +174,14 @@
test_bit(EXTENT_FLAG_LOGGING, &next->flags))
return 0;
+ /*
+ * We don't want to merge stuff that hasn't been written to the log yet
+ * since it may not reflect exactly what is on disk, and that would be
+ * bad.
+ */
+ if (!list_empty(&prev->list) || !list_empty(&next->list))
+ return 0;
+
if (extent_map_end(prev) == next->start &&
prev->flags == next->flags &&
prev->bdev == next->bdev &&
@@ -209,9 +217,7 @@
em->mod_len = (em->mod_len + em->mod_start) - merge->mod_start;
em->mod_start = merge->mod_start;
em->generation = max(em->generation, merge->generation);
- list_move(&em->list, &tree->modified_extents);
- list_del_init(&merge->list);
rb_erase(&merge->rb_node, &tree->map);
free_extent_map(merge);
}
@@ -227,7 +233,6 @@
merge->in_tree = 0;
em->mod_len = (merge->mod_start + merge->mod_len) - em->mod_start;
em->generation = max(em->generation, merge->generation);
- list_del_init(&merge->list);
free_extent_map(merge);
}
}
@@ -302,7 +307,7 @@
* reference dropped if the merge attempt was successful.
*/
int add_extent_mapping(struct extent_map_tree *tree,
- struct extent_map *em)
+ struct extent_map *em, int modified)
{
int ret = 0;
struct rb_node *rb;
@@ -324,7 +329,10 @@
em->mod_start = em->start;
em->mod_len = em->len;
- try_merge_map(tree, em);
+ if (modified)
+ list_move(&em->list, &tree->modified_extents);
+ else
+ try_merge_map(tree, em);
out:
return ret;
}
diff --git a/fs/btrfs/extent_map.h b/fs/btrfs/extent_map.h
index b18314b..61adc44 100644
--- a/fs/btrfs/extent_map.h
+++ b/fs/btrfs/extent_map.h
@@ -62,7 +62,7 @@
struct extent_map *lookup_extent_mapping(struct extent_map_tree *tree,
u64 start, u64 len);
int add_extent_mapping(struct extent_map_tree *tree,
- struct extent_map *em);
+ struct extent_map *em, int modified);
int remove_extent_mapping(struct extent_map_tree *tree, struct extent_map *em);
struct extent_map *alloc_extent_map(void);
diff --git a/fs/btrfs/file.c b/fs/btrfs/file.c
index e81e428..a56abed 100644
--- a/fs/btrfs/file.c
+++ b/fs/btrfs/file.c
@@ -552,6 +552,7 @@
int testend = 1;
unsigned long flags;
int compressed = 0;
+ bool modified;
WARN_ON(end < start);
if (end == (u64)-1) {
@@ -561,6 +562,7 @@
while (1) {
int no_splits = 0;
+ modified = false;
if (!split)
split = alloc_extent_map();
if (!split2)
@@ -592,6 +594,7 @@
compressed = test_bit(EXTENT_FLAG_COMPRESSED, &em->flags);
clear_bit(EXTENT_FLAG_PINNED, &em->flags);
clear_bit(EXTENT_FLAG_LOGGING, &flags);
+ modified = !list_empty(&em->list);
remove_extent_mapping(em_tree, em);
if (no_splits)
goto next;
@@ -614,9 +617,8 @@
split->bdev = em->bdev;
split->flags = flags;
split->compress_type = em->compress_type;
- ret = add_extent_mapping(em_tree, split);
+ ret = add_extent_mapping(em_tree, split, modified);
BUG_ON(ret); /* Logic error */
- list_move(&split->list, &em_tree->modified_extents);
free_extent_map(split);
split = split2;
split2 = NULL;
@@ -645,9 +647,8 @@
split->orig_start = em->orig_start;
}
- ret = add_extent_mapping(em_tree, split);
+ ret = add_extent_mapping(em_tree, split, modified);
BUG_ON(ret); /* Logic error */
- list_move(&split->list, &em_tree->modified_extents);
free_extent_map(split);
split = NULL;
}
@@ -1930,10 +1931,7 @@
do {
btrfs_drop_extent_cache(inode, offset, end - 1, 0);
write_lock(&em_tree->lock);
- ret = add_extent_mapping(em_tree, hole_em);
- if (!ret)
- list_move(&hole_em->list,
- &em_tree->modified_extents);
+ ret = add_extent_mapping(em_tree, hole_em, 1);
write_unlock(&em_tree->lock);
} while (ret == -EEXIST);
free_extent_map(hole_em);
diff --git a/fs/btrfs/inode.c b/fs/btrfs/inode.c
index 456667b..c41637a 100644
--- a/fs/btrfs/inode.c
+++ b/fs/btrfs/inode.c
@@ -732,10 +732,7 @@
while (1) {
write_lock(&em_tree->lock);
- ret = add_extent_mapping(em_tree, em);
- if (!ret)
- list_move(&em->list,
- &em_tree->modified_extents);
+ ret = add_extent_mapping(em_tree, em, 1);
write_unlock(&em_tree->lock);
if (ret != -EEXIST) {
free_extent_map(em);
@@ -941,10 +938,7 @@
while (1) {
write_lock(&em_tree->lock);
- ret = add_extent_mapping(em_tree, em);
- if (!ret)
- list_move(&em->list,
- &em_tree->modified_extents);
+ ret = add_extent_mapping(em_tree, em, 1);
write_unlock(&em_tree->lock);
if (ret != -EEXIST) {
free_extent_map(em);
@@ -1387,10 +1381,7 @@
em->generation = -1;
while (1) {
write_lock(&em_tree->lock);
- ret = add_extent_mapping(em_tree, em);
- if (!ret)
- list_move(&em->list,
- &em_tree->modified_extents);
+ ret = add_extent_mapping(em_tree, em, 1);
write_unlock(&em_tree->lock);
if (ret != -EEXIST) {
free_extent_map(em);
@@ -4467,10 +4458,7 @@
while (1) {
write_lock(&em_tree->lock);
- err = add_extent_mapping(em_tree, hole_em);
- if (!err)
- list_move(&hole_em->list,
- &em_tree->modified_extents);
+ err = add_extent_mapping(em_tree, hole_em, 1);
write_unlock(&em_tree->lock);
if (err != -EEXIST)
break;
@@ -5989,7 +5977,7 @@
em->block_start += start_diff;
em->block_len -= start_diff;
}
- return add_extent_mapping(em_tree, em);
+ return add_extent_mapping(em_tree, em, 0);
}
static noinline int uncompress_inline(struct btrfs_path *path,
@@ -6283,7 +6271,7 @@
err = 0;
write_lock(&em_tree->lock);
- ret = add_extent_mapping(em_tree, em);
+ ret = add_extent_mapping(em_tree, em, 0);
/* it is possible that someone inserted the extent into the tree
* while we had the lock dropped. It is also possible that
* an overlapping map exists in the tree
@@ -6706,10 +6694,7 @@
btrfs_drop_extent_cache(inode, em->start,
em->start + em->len - 1, 0);
write_lock(&em_tree->lock);
- ret = add_extent_mapping(em_tree, em);
- if (!ret)
- list_move(&em->list,
- &em_tree->modified_extents);
+ ret = add_extent_mapping(em_tree, em, 1);
write_unlock(&em_tree->lock);
} while (ret == -EEXIST);
@@ -8593,10 +8578,7 @@
while (1) {
write_lock(&em_tree->lock);
- ret = add_extent_mapping(em_tree, em);
- if (!ret)
- list_move(&em->list,
- &em_tree->modified_extents);
+ ret = add_extent_mapping(em_tree, em, 1);
write_unlock(&em_tree->lock);
if (ret != -EEXIST)
break;
diff --git a/fs/btrfs/relocation.c b/fs/btrfs/relocation.c
index 4ef5f74..2081549 100644
--- a/fs/btrfs/relocation.c
+++ b/fs/btrfs/relocation.c
@@ -2979,7 +2979,7 @@
lock_extent(&BTRFS_I(inode)->io_tree, start, end);
while (1) {
write_lock(&em_tree->lock);
- ret = add_extent_mapping(em_tree, em);
+ ret = add_extent_mapping(em_tree, em, 0);
write_unlock(&em_tree->lock);
if (ret != -EEXIST) {
free_extent_map(em);
diff --git a/fs/btrfs/tree-log.c b/fs/btrfs/tree-log.c
index 592aa65..b069faf 100644
--- a/fs/btrfs/tree-log.c
+++ b/fs/btrfs/tree-log.c
@@ -3209,115 +3209,6 @@
return 0;
}
-static int drop_adjacent_extents(struct btrfs_trans_handle *trans,
- struct btrfs_root *root, struct inode *inode,
- struct extent_map *em,
- struct btrfs_path *path)
-{
- struct btrfs_file_extent_item *fi;
- struct extent_buffer *leaf;
- struct btrfs_key key, new_key;
- struct btrfs_map_token token;
- u64 extent_end;
- u64 extent_offset = 0;
- int extent_type;
- int del_slot = 0;
- int del_nr = 0;
- int ret = 0;
-
- while (1) {
- btrfs_init_map_token(&token);
- leaf = path->nodes[0];
- path->slots[0]++;
- if (path->slots[0] >= btrfs_header_nritems(leaf)) {
- if (del_nr) {
- ret = btrfs_del_items(trans, root, path,
- del_slot, del_nr);
- if (ret)
- return ret;
- del_nr = 0;
- }
-
- ret = btrfs_next_leaf_write(trans, root, path, 1);
- if (ret < 0)
- return ret;
- if (ret > 0)
- return 0;
- leaf = path->nodes[0];
- }
-
- btrfs_item_key_to_cpu(leaf, &key, path->slots[0]);
- if (key.objectid != btrfs_ino(inode) ||
- key.type != BTRFS_EXTENT_DATA_KEY ||
- key.offset >= em->start + em->len)
- break;
-
- fi = btrfs_item_ptr(leaf, path->slots[0],
- struct btrfs_file_extent_item);
- extent_type = btrfs_token_file_extent_type(leaf, fi, &token);
- if (extent_type == BTRFS_FILE_EXTENT_REG ||
- extent_type == BTRFS_FILE_EXTENT_PREALLOC) {
- extent_offset = btrfs_token_file_extent_offset(leaf,
- fi, &token);
- extent_end = key.offset +
- btrfs_token_file_extent_num_bytes(leaf, fi,
- &token);
- } else if (extent_type == BTRFS_FILE_EXTENT_INLINE) {
- extent_end = key.offset +
- btrfs_file_extent_inline_len(leaf, fi);
- } else {
- BUG();
- }
-
- if (extent_end <= em->len + em->start) {
- if (!del_nr) {
- del_slot = path->slots[0];
- }
- del_nr++;
- continue;
- }
-
- /*
- * Ok so we'll ignore previous items if we log a new extent,
- * which can lead to overlapping extents, so if we have an
- * existing extent we want to adjust we _have_ to check the next
- * guy to make sure we even need this extent anymore, this keeps
- * us from panicing in set_item_key_safe.
- */
- if (path->slots[0] < btrfs_header_nritems(leaf) - 1) {
- struct btrfs_key tmp_key;
-
- btrfs_item_key_to_cpu(leaf, &tmp_key,
- path->slots[0] + 1);
- if (tmp_key.objectid == btrfs_ino(inode) &&
- tmp_key.type == BTRFS_EXTENT_DATA_KEY &&
- tmp_key.offset <= em->start + em->len) {
- if (!del_nr)
- del_slot = path->slots[0];
- del_nr++;
- continue;
- }
- }
-
- BUG_ON(extent_type == BTRFS_FILE_EXTENT_INLINE);
- memcpy(&new_key, &key, sizeof(new_key));
- new_key.offset = em->start + em->len;
- btrfs_set_item_key_safe(trans, root, path, &new_key);
- extent_offset += em->start + em->len - key.offset;
- btrfs_set_token_file_extent_offset(leaf, fi, extent_offset,
- &token);
- btrfs_set_token_file_extent_num_bytes(leaf, fi, extent_end -
- (em->start + em->len),
- &token);
- btrfs_mark_buffer_dirty(leaf);
- }
-
- if (del_nr)
- ret = btrfs_del_items(trans, root, path, del_slot, del_nr);
-
- return ret;
-}
-
static int log_one_extent(struct btrfs_trans_handle *trans,
struct inode *inode, struct btrfs_root *root,
struct extent_map *em, struct btrfs_path *path)
@@ -3339,39 +3230,24 @@
int index = log->log_transid % 2;
bool skip_csum = BTRFS_I(inode)->flags & BTRFS_INODE_NODATASUM;
-insert:
+ ret = __btrfs_drop_extents(trans, log, inode, path, em->start,
+ em->start + em->len, NULL, 0);
+ if (ret)
+ return ret;
+
INIT_LIST_HEAD(&ordered_sums);
btrfs_init_map_token(&token);
key.objectid = btrfs_ino(inode);
key.type = BTRFS_EXTENT_DATA_KEY;
key.offset = em->start;
- path->really_keep_locks = 1;
ret = btrfs_insert_empty_item(trans, log, path, &key, sizeof(*fi));
- if (ret && ret != -EEXIST) {
- path->really_keep_locks = 0;
+ if (ret)
return ret;
- }
leaf = path->nodes[0];
fi = btrfs_item_ptr(leaf, path->slots[0],
struct btrfs_file_extent_item);
- /*
- * If we are overwriting an inline extent with a real one then we need
- * to just delete the inline extent as it may not be large enough to
- * have the entire file_extent_item.
- */
- if (ret && btrfs_token_file_extent_type(leaf, fi, &token) ==
- BTRFS_FILE_EXTENT_INLINE) {
- ret = btrfs_del_item(trans, log, path);
- btrfs_release_path(path);
- if (ret) {
- path->really_keep_locks = 0;
- return ret;
- }
- goto insert;
- }
-
btrfs_set_token_file_extent_generation(leaf, fi, em->generation,
&token);
if (test_bit(EXTENT_FLAG_PREALLOC, &em->flags)) {
@@ -3417,15 +3293,7 @@
btrfs_set_token_file_extent_other_encoding(leaf, fi, 0, &token);
btrfs_mark_buffer_dirty(leaf);
- /*
- * Have to check the extent to the right of us to make sure it doesn't
- * fall in our current range. We're ok if the previous extent is in our
- * range since the recovery stuff will run us in key order and thus just
- * drop the part we overwrote.
- */
- ret = drop_adjacent_extents(trans, log, inode, em, path);
btrfs_release_path(path);
- path->really_keep_locks = 0;
if (ret) {
return ret;
}
diff --git a/fs/btrfs/volumes.c b/fs/btrfs/volumes.c
index 3994767..0d7ab7e 100644
--- a/fs/btrfs/volumes.c
+++ b/fs/btrfs/volumes.c
@@ -3932,7 +3932,7 @@
em_tree = &extent_root->fs_info->mapping_tree.map_tree;
write_lock(&em_tree->lock);
- ret = add_extent_mapping(em_tree, em);
+ ret = add_extent_mapping(em_tree, em, 0);
write_unlock(&em_tree->lock);
if (ret) {
free_extent_map(em);
@@ -5476,7 +5476,7 @@
}
write_lock(&map_tree->map_tree.lock);
- ret = add_extent_mapping(&map_tree->map_tree, em);
+ ret = add_extent_mapping(&map_tree->map_tree, em, 0);
write_unlock(&map_tree->map_tree.lock);
BUG_ON(ret); /* Tree corruption */
free_extent_map(em);