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-rw-r--r--fs/ext4/inode.c63
1 files changed, 61 insertions, 2 deletions
diff --git a/fs/ext4/inode.c b/fs/ext4/inode.c
index 48fc023ab0a2..65bbc9339aca 100644
--- a/fs/ext4/inode.c
+++ b/fs/ext4/inode.c
@@ -1305,6 +1305,55 @@ static int ext4_journalled_write_end(struct file *file,
}
/*
+ * Reserve a metadata for a single block located at lblock
+ */
+static int ext4_da_reserve_metadata(struct inode *inode, ext4_lblk_t lblock)
+{
+ int retries = 0;
+ struct ext4_sb_info *sbi = EXT4_SB(inode->i_sb);
+ struct ext4_inode_info *ei = EXT4_I(inode);
+ unsigned int md_needed;
+ ext4_lblk_t save_last_lblock;
+ int save_len;
+
+ /*
+ * recalculate the amount of metadata blocks to reserve
+ * in order to allocate nrblocks
+ * worse case is one extent per block
+ */
+repeat:
+ spin_lock(&ei->i_block_reservation_lock);
+ /*
+ * ext4_calc_metadata_amount() has side effects, which we have
+ * to be prepared undo if we fail to claim space.
+ */
+ save_len = ei->i_da_metadata_calc_len;
+ save_last_lblock = ei->i_da_metadata_calc_last_lblock;
+ md_needed = EXT4_NUM_B2C(sbi,
+ ext4_calc_metadata_amount(inode, lblock));
+ trace_ext4_da_reserve_space(inode, md_needed);
+
+ /*
+ * We do still charge estimated metadata to the sb though;
+ * we cannot afford to run out of free blocks.
+ */
+ if (ext4_claim_free_clusters(sbi, md_needed, 0)) {
+ ei->i_da_metadata_calc_len = save_len;
+ ei->i_da_metadata_calc_last_lblock = save_last_lblock;
+ spin_unlock(&ei->i_block_reservation_lock);
+ if (ext4_should_retry_alloc(inode->i_sb, &retries)) {
+ cond_resched();
+ goto repeat;
+ }
+ return -ENOSPC;
+ }
+ ei->i_reserved_meta_blocks += md_needed;
+ spin_unlock(&ei->i_block_reservation_lock);
+
+ return 0; /* success */
+}
+
+/*
* Reserve a single cluster located at lblock
*/
static int ext4_da_reserve_space(struct inode *inode, ext4_lblk_t lblock)
@@ -1940,8 +1989,11 @@ add_delayed:
* XXX: __block_prepare_write() unmaps passed block,
* is it OK?
*/
- /* If the block was allocated from previously allocated cluster,
- * then we dont need to reserve it again. */
+ /*
+ * If the block was allocated from previously allocated cluster,
+ * then we don't need to reserve it again. However we still need
+ * to reserve metadata for every block we're going to write.
+ */
if (!(map->m_flags & EXT4_MAP_FROM_CLUSTER)) {
ret = ext4_da_reserve_space(inode, iblock);
if (ret) {
@@ -1949,6 +2001,13 @@ add_delayed:
retval = ret;
goto out_unlock;
}
+ } else {
+ ret = ext4_da_reserve_metadata(inode, iblock);
+ if (ret) {
+ /* not enough space to reserve */
+ retval = ret;
+ goto out_unlock;
+ }
}
ret = ext4_es_insert_extent(inode, map->m_lblk, map->m_len,