From: Theodore Ts'o <tytso@xxxxxxx>
commit eb7054212eac8b451d727bf079eae3db8c88f9d3 upstream.
If we (re-)calculate the file system overhead amount and it's
different from the on-disk s_overhead_clusters value, update the
on-disk version since this can take potentially quite a while on
bigalloc file systems.
Signed-off-by: Theodore Ts'o <tytso@xxxxxxx>
Cc: stable@xxxxxxxxxx
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
---
fs/ext4/ext4.h | 1 +
fs/ext4/ioctl.c | 16 ++++++++++++++++
fs/ext4/super.c | 2 ++
3 files changed, 19 insertions(+)
--- a/fs/ext4/ext4.h
+++ b/fs/ext4/ext4.h
@@ -3066,6 +3066,7 @@ int ext4_fileattr_set(struct user_namesp
struct dentry *dentry, struct fileattr *fa);
int ext4_fileattr_get(struct dentry *dentry, struct fileattr *fa);
extern void ext4_reset_inode_seed(struct inode *inode);
+int ext4_update_overhead(struct super_block *sb);
/* migrate.c */
extern int ext4_ext_migrate(struct inode *);
--- a/fs/ext4/ioctl.c
+++ b/fs/ext4/ioctl.c
@@ -1652,3 +1652,19 @@ long ext4_compat_ioctl(struct file *file
return ext4_ioctl(file, cmd, (unsigned long) compat_ptr(arg));
}
#endif
+
+static void set_overhead(struct ext4_super_block *es, const void *arg)
+{
+ es->s_overhead_clusters = cpu_to_le32(*((unsigned long *) arg));
+}
+
+int ext4_update_overhead(struct super_block *sb)
+{
+ struct ext4_sb_info *sbi = EXT4_SB(sb);
+
+ if (sb_rdonly(sb) || sbi->s_overhead == 0 ||
+ sbi->s_overhead == le32_to_cpu(sbi->s_es->s_overhead_clusters))
+ return 0;
+
+ return ext4_update_superblocks_fn(sb, set_overhead, &sbi->s_overhead);
+}
--- a/fs/ext4/super.c
+++ b/fs/ext4/super.c
@@ -5597,6 +5597,8 @@ static int ext4_fill_super(struct super_
ext4_msg(sb, KERN_INFO, "mounted filesystem with%s. "
"Quota mode: %s.", descr, ext4_quota_mode(sb));
+ /* Update the s_overhead_clusters if necessary */
+ ext4_update_overhead(sb);
return 0;
free_sbi:
