From: Chunguang Xu <brookxu@xxxxxxxxxxx>
There is a need to check whether a block or a segment overlaps
with metadata, since information of system_zone is incomplete,
we need a more accurate function. Now we check whether it
overlaps with block bitmap, inode bitmap, and inode table.
Perhaps it is better to add a check of super_block and block
group descriptor and provide a helper function.
Signed-off-by: Chunguang Xu <brookxu@xxxxxxxxxxx>
---
fs/ext4/ext4.h | 5 ++++-
fs/ext4/mballoc.c | 57 +++++++++++++++++++++++++++++++++++++++++++------------
2 files changed, 49 insertions(+), 13 deletions(-)
diff --git a/fs/ext4/ext4.h b/fs/ext4/ext4.h
index bd88b4a..73d59cb 100644
--- a/fs/ext4/ext4.h
+++ b/fs/ext4/ext4.h
@@ -2801,7 +2801,10 @@ extern ext4_group_t ext4_mb_prefetch(struct super_block *sb,
unsigned int nr, int *cnt);
extern void ext4_mb_prefetch_fini(struct super_block *sb, ext4_group_t group,
unsigned int nr);
-
+extern int ext4_metadata_block_overlaps(struct super_block *sb,
+ ext4_group_t block_group,
+ ext4_fsblk_t block,
+ unsigned long count);
extern void ext4_free_blocks(handle_t *handle, struct inode *inode,
struct buffer_head *bh, ext4_fsblk_t block,
unsigned long count, int flags);
diff --git a/fs/ext4/mballoc.c b/fs/ext4/mballoc.c
index 29dfeb04..d8704fe 100644
--- a/fs/ext4/mballoc.c
+++ b/fs/ext4/mballoc.c
@@ -5061,6 +5061,49 @@ static void ext4_try_merge_freed_extent(struct ext4_sb_info *sbi,
kmem_cache_free(ext4_free_data_cachep, entry);
}
+/*
+ * Returns 1 if the passed-in block region (block, block+count)
+ * overlaps with some other filesystem metadata blocks. Others,
+ * return 0.
+ */
+int ext4_metadata_block_overlaps(struct super_block *sb,
+ ext4_group_t block_group,
+ ext4_fsblk_t block,
+ unsigned long count)
+{
+ struct ext4_sb_info *sbi = EXT4_SB(sb);
+ struct ext4_group_desc *gdp;
+ int gd_first = ext4_group_first_block_no(sb, block_group);
+ int itable, gd_blk;
+ int ret = 0;
+
+ gdp = ext4_get_group_desc(sb, block_group, NULL);
+ // check block bitmap and inode bitmap
+ if (in_range(ext4_block_bitmap(sb, gdp), block, count) ||
+ in_range(ext4_inode_bitmap(sb, gdp), block, count))
+ ret = 1;
+
+ // check inode table
+ itable = ext4_inode_table(sb, gdp);
+ if (!(block >= itable + sbi->s_itb_per_group ||
+ block + count - 1 < itable))
+ ret = 1;
+
+ /* check super_block and block group descriptor table, the
+ * reserved space of the block group descriptor is managed
+ * by resize_inode, it may not be processed now due to
+ * performance.
+ */
+ gd_blk = ext4_bg_has_super(sb, block_group) +
+ ext4_bg_num_gdb(sb, block_group);
+ if (gd_blk) {
+ if (!(block >= gd_first + gd_blk ||
+ block + count - 1 < gd_first))
+ ret = 1;
+ }
+ return ret;
+}
+
static noinline_for_stack int
ext4_mb_free_metadata(handle_t *handle, struct ext4_buddy *e4b,
struct ext4_free_data *new_entry)
@@ -5360,13 +5403,7 @@ void ext4_free_blocks(handle_t *handle, struct inode *inode,
goto error_return;
}
- if (in_range(ext4_block_bitmap(sb, gdp), block, count) ||
- in_range(ext4_inode_bitmap(sb, gdp), block, count) ||
- in_range(block, ext4_inode_table(sb, gdp),
- sbi->s_itb_per_group) ||
- in_range(block + count - 1, ext4_inode_table(sb, gdp),
- sbi->s_itb_per_group)) {
-
+ if (ext4_metadata_block_overlaps(sb, block_group, block, count)) {
ext4_error(sb, "Freeing blocks in system zone - "
"Block = %llu, count = %lu", block, count);
/* err = 0. ext4_std_error should be a no op */
@@ -5552,11 +5589,7 @@ int ext4_group_add_blocks(handle_t *handle, struct super_block *sb,
goto error_return;
}
- if (in_range(ext4_block_bitmap(sb, desc), block, count) ||
- in_range(ext4_inode_bitmap(sb, desc), block, count) ||
- in_range(block, ext4_inode_table(sb, desc), sbi->s_itb_per_group) ||
- in_range(block + count - 1, ext4_inode_table(sb, desc),
- sbi->s_itb_per_group)) {
+ if (ext4_metadata_block_overlaps(sb, block_group, block, count)) {
ext4_error(sb, "Adding blocks in system zones - "
"Block = %llu, count = %lu",
block, count);
--
1.8.3.1
