From 7a9ca53aea10ad4677a0f347ad7639c304b80194 Mon Sep 17 00:00:00 2001 From: Tahsin Erdogan Date: Thu, 22 Jun 2017 11:46:48 -0400 Subject: quota: add get_inode_usage callback to transfer multi-inode charges Ext4 ea_inode feature allows storing xattr values in external inodes to be able to store values that are bigger than a block in size. Ext4 also has deduplication support for these type of inodes. With deduplication, the actual storage waste is eliminated but the users of such inodes are still charged full quota for the inodes as if there was no sharing happening in the background. This design requires ext4 to manually charge the users because the inodes are shared. An implication of this is that, if someone calls chown on a file that has such references we need to transfer the quota for the file and xattr inodes. Current dquot_transfer() function implicitly transfers one inode charge. With ea_inode feature, we would like to transfer multiple inode charges. Add get_inode_usage callback which can interrogate the total number of inodes that were charged for a given inode. [ Applied fix from Colin King to make sure the 'ret' variable is initialized on the successful return path. Detected by CoverityScan, CID#1446616 ("Uninitialized scalar variable") --tytso] Signed-off-by: Tahsin Erdogan Signed-off-by: Theodore Ts'o Signed-off-by: Colin Ian King Acked-by: Jan Kara --- fs/ext4/ioctl.c | 6 ++++++ 1 file changed, 6 insertions(+) (limited to 'fs/ext4/ioctl.c') diff --git a/fs/ext4/ioctl.c b/fs/ext4/ioctl.c index dde8deb11e59..42b3a73143cf 100644 --- a/fs/ext4/ioctl.c +++ b/fs/ext4/ioctl.c @@ -373,7 +373,13 @@ static int ext4_ioctl_setproject(struct file *filp, __u32 projid) transfer_to[PRJQUOTA] = dqget(sb, make_kqid_projid(kprojid)); if (!IS_ERR(transfer_to[PRJQUOTA])) { + + /* __dquot_transfer() calls back ext4_get_inode_usage() which + * counts xattr inode references. + */ + down_read(&EXT4_I(inode)->xattr_sem); err = __dquot_transfer(inode, transfer_to); + up_read(&EXT4_I(inode)->xattr_sem); dqput(transfer_to[PRJQUOTA]); if (err) goto out_dirty; -- cgit v1.2.1