Since the read operation beyond the ValidDataLength returns zero,
if we just extend the size of the file, we don't need to zero the
extended part, but only change the DataLength without changing
the ValidDataLength.
Signed-off-by: Yuezhang Mo <Yuezhang.Mo@xxxxxxxx>
Reviewed-by: Andy Wu <Andy.Wu@xxxxxxxx>
Reviewed-by: Aoyama Wataru <wataru.aoyama@xxxxxxxx>
---
fs/exfat/file.c | 77 ++++++++++++++++++++++++++++++++++++++++++++++++-
1 file changed, 76 insertions(+), 1 deletion(-)
diff --git a/fs/exfat/file.c b/fs/exfat/file.c
index 8cd14bc16857..62a21c45517d 100644
--- a/fs/exfat/file.c
+++ b/fs/exfat/file.c
@@ -13,7 +13,7 @@
#include "exfat_raw.h"
#include "exfat_fs.h"
-static int exfat_cont_expand(struct inode *inode, loff_t size)
+static int exfat_expand_and_zero(struct inode *inode, loff_t size)
{
struct address_space *mapping = inode->i_mapping;
loff_t start = i_size_read(inode), count = size - i_size_read(inode);
@@ -43,6 +43,81 @@ static int exfat_cont_expand(struct inode *inode, loff_t size)
return filemap_fdatawait_range(mapping, start, start + count - 1);
}
+static int exfat_expand(struct inode *inode, loff_t size)
+{
+ int ret;
+ unsigned int num_clusters, new_num_clusters, last_clu;
+ struct exfat_inode_info *ei = EXFAT_I(inode);
+ struct super_block *sb = inode->i_sb;
+ struct exfat_sb_info *sbi = EXFAT_SB(sb);
+ struct exfat_chain clu;
+
+ ret = inode_newsize_ok(inode, size);
+ if (ret)
+ return ret;
+
+ num_clusters = EXFAT_B_TO_CLU_ROUND_UP(i_size_read(inode), sbi);
+ new_num_clusters = EXFAT_B_TO_CLU_ROUND_UP(size, sbi);
+
+ if (new_num_clusters == num_clusters)
+ goto out;
+
+ exfat_chain_set(&clu, ei->start_clu, num_clusters, ei->flags);
+ ret = exfat_find_last_cluster(sb, &clu, &last_clu);
+ if (ret)
+ return ret;
+
+ clu.dir = (last_clu == EXFAT_EOF_CLUSTER) ?
+ EXFAT_EOF_CLUSTER : last_clu + 1;
+ clu.size = 0;
+ clu.flags = ei->flags;
+
+ ret = exfat_alloc_cluster(inode, new_num_clusters - num_clusters,
+ &clu, IS_DIRSYNC(inode));
+ if (ret)
+ return ret;
+
+ /* Append new clusters to chain */
+ if (clu.flags != ei->flags) {
+ exfat_chain_cont_cluster(sb, ei->start_clu, num_clusters);
+ ei->flags = ALLOC_FAT_CHAIN;
+ }
+ if (clu.flags == ALLOC_FAT_CHAIN)
+ if (exfat_ent_set(sb, last_clu, clu.dir))
+ goto free_clu;
+
+ if (num_clusters == 0)
+ ei->start_clu = clu.dir;
+
+out:
+ inode->i_ctime = inode->i_mtime = current_time(inode);
+ /* Expanded range not zeroed, do not update valid_size */
+ i_size_write(inode, size);
+
+ ei->i_size_aligned = round_up(size, sb->s_blocksize);
+ ei->i_size_ondisk = ei->i_size_aligned;
+ inode->i_blocks = round_up(size, sbi->cluster_size) >> 9;
+
+ if (IS_DIRSYNC(inode))
+ return write_inode_now(inode, 1);
+
+ mark_inode_dirty(inode);
+
+ return 0;
+
+free_clu:
+ exfat_free_cluster(inode, &clu);
+ return -EIO;
+}
+
+static int exfat_cont_expand(struct inode *inode, loff_t size)
+{
+ if (mapping_writably_mapped(inode->i_mapping))
+ return exfat_expand_and_zero(inode, size);
+
+ return exfat_expand(inode, size);
+}
+
static bool exfat_allow_set_time(struct exfat_sb_info *sbi, struct inode *inode)
{
mode_t allow_utime = sbi->options.allow_utime;
--
2.25.1
