ext4: elevate write count for migrate ioctl

Aneesh Kumar K.V
2008-09-12T09:04:20Z

From: Aneesh Kumar K.V <aneesh.kumar@linux.vnet.ibm.com>

migrate ioctl writes to the filsystem. So we need to
elevate the write count.

Signed-off-by: Aneesh Kumar K.V <aneesh.kumar@linux.vnet.ibm.com>
---
fs/ext4/ext4.h | 3 +--
fs/ext4/ioctl.c | 21 ++++++++++++++++++++-
fs/ext4/migrate.c | 10 +---------
3 files changed, 22 insertions(+), 12 deletions(-)

diff --git a/fs/ext4/ext4.h b/fs/ext4/ext4.h
index bc856e3..103892b 100644
--- a/fs/ext4/ext4.h
+++ b/fs/ext4/ext4.h
@@ -1165,8 +1165,7 @@ extern long ext4_ioctl(struct file *, unsigned int, unsigned long);
extern long ext4_compat_ioctl (struct file *, unsigned int, unsigned long);

/* migrate.c */
-extern int ext4_ext_migrate(struct inode *, struct file *, unsigned int,
- unsigned long);
+extern int ext4_ext_migrate(struct inode *);
/* namei.c */
extern int ext4_orphan_add(handle_t *, struct inode *);
extern int ext4_orphan_del(handle_t *, struct inode *);
diff --git a/fs/ext4/ioctl.c b/fs/ext4/ioctl.c
index 9daa40a..6e02967 100644
--- a/fs/ext4/ioctl.c
+++ b/fs/ext4/ioctl.c
@@ -277,7 +277,26 @@ long ext4_ioctl(struct file *filp, unsigned int cmd, unsigned long arg)
}

case EXT4_IOC_MIGRATE:
- return ext4_ext_migrate(inode, filp, cmd, arg);
+ {
+ int err;
+ if (!is_owner_or_cap(inode))
+ return -EACCES;
+
+ err = mnt_want_write(filp->f_path.mnt);
+ if (err)
+ return err;
+ /*
+ * inode_mutex prevent write and truncate on the file.
+ * Read still goes through. We take i_data_sem in
+ * ext4_ext_swap_inode_data before we switch the
+ * inode format to prevent read.
+ */
+ mutex_lock(&(inode->i_mutex));
+ err = ext4_ext_migrate(inode);
+ mutex_unlock(&(inode->i_mutex));
+ mnt_drop_write(filp->f_path.mnt);
+ return err;
+ }

default:
return -ENOTTY;
diff --git a/fs/ext4/migrate.c b/fs/ext4/migrate.c
index 46fc0b5..f2a9cf4 100644
--- a/fs/ext4/migrate.c
+++ b/fs/ext4/migrate.c
@@ -447,8 +447,7 @@ static int free_ext_block(handle_t *handle, struct inode *inode)

}

-int ext4_ext_migrate(struct inode *inode, struct file *filp,
- unsigned int cmd, unsigned long arg)
+int ext4_ext_migrate(struct inode *inode)
{
handle_t *handle;
int retval = 0, i;
@@ -516,12 +515,6 @@ int ext4_ext_migrate(struct inode *inode, struct file *filp,
* when we add extents we extent the journal
*/
/*
- * inode_mutex prevent write and truncate on the file. Read still goes
- * through. We take i_data_sem in ext4_ext_swap_inode_data before we
- * switch the inode format to prevent read.
- */
- mutex_lock(&(inode->i_mutex));
- /*
* Even though we take i_mutex we can still cause block allocation
* via mmap write to holes. If we have allocated new blocks we fail
* migrate. New block allocation will clear EXT4_EXT_MIGRATE flag.
@@ -623,7 +616,6 @@ int ext4_ext_migrate(struct inode *inode, struct file *filp,
tmp_inode->i_nlink = 0;

ext4_journal_stop(handle);
- mutex_unlock(&(inode->i_mutex));

if (tmp_inode)
iput(tmp_inode);