Message-Id: <0F8FAF43-54EB-4202-8120-C1D70CF330F0@dilger.ca>
Date:	Wed, 7 Jan 2015 16:11:16 -0700
From:	Andreas Dilger <adilger@...ger.ca>
To:	Li Xi <pkuelelixi@...il.com>
Cc:	linux-fsdevel@...r.kernel.org, linux-ext4@...r.kernel.org,
	linux-api@...r.kernel.org, tytso@....edu, jack@...e.cz,
	viro@...iv.linux.org.uk, hch@...radead.org, dmonakhov@...nvz.org
Subject: Re: [v8 2/5] ext4: adds project ID support

On Dec 8, 2014, at 10:22 PM, Li Xi <pkuelelixi@...il.com> wrote:
> This patch adds a new internal field of ext4 inode to save project
> identifier. Also a new flag EXT4_INODE_PROJINHERIT is added for
> inheriting project ID from parent directory.
> 
> Signed-off-by: Li Xi <lixi@....com>
> Reviewed-by: Jan Kara <jack@...e.cz>
> ---
> fs/ext4/ext4.h          |   21 +++++++++++++++++----
> fs/ext4/ialloc.c        |    6 ++++++
> fs/ext4/inode.c         |   29 +++++++++++++++++++++++++++++
> fs/ext4/namei.c         |   17 +++++++++++++++++
> fs/ext4/super.c         |    1 +
> include/uapi/linux/fs.h |    1 +
> 6 files changed, 71 insertions(+), 4 deletions(-)
> 
> diff --git a/fs/ext4/ext4.h b/fs/ext4/ext4.h
> index 29c43e7..8bd1da9 100644
> --- a/fs/ext4/ext4.h
> +++ b/fs/ext4/ext4.h
> @@ -377,16 +377,18 @@ struct flex_groups {
> #define EXT4_EA_INODE_FL	        0x00200000 /* Inode used for large EA */
> #define EXT4_EOFBLOCKS_FL		0x00400000 /* Blocks allocated beyond EOF */
> #define EXT4_INLINE_DATA_FL		0x10000000 /* Inode has inline data. */
> +#define EXT4_PROJINHERIT_FL		FS_PROJINHERIT_FL /* Create with parents projid */

Sigh, only a single on-disk inode flag unused.

> #define EXT4_RESERVED_FL		0x80000000 /* reserved for ext4 lib */
> 
> -#define EXT4_FL_USER_VISIBLE		0x004BDFFF /* User visible flags */
> -#define EXT4_FL_USER_MODIFIABLE		0x004380FF /* User modifiable flags */
> +#define EXT4_FL_USER_VISIBLE		0x204BDFFF /* User visible flags */
> +#define EXT4_FL_USER_MODIFIABLE		0x204380FF /* User modifiable flags */
> 
> /* Flags that should be inherited by new inodes from their parent. */
> #define EXT4_FL_INHERITED (EXT4_SECRM_FL | EXT4_UNRM_FL | EXT4_COMPR_FL |\
> 			   EXT4_SYNC_FL | EXT4_NODUMP_FL | EXT4_NOATIME_FL |\
> 			   EXT4_NOCOMPR_FL | EXT4_JOURNAL_DATA_FL |\
> -			   EXT4_NOTAIL_FL | EXT4_DIRSYNC_FL)
> +			   EXT4_NOTAIL_FL | EXT4_DIRSYNC_FL |\
> +			   EXT4_PROJINHERIT_FL)
> 
> /* Flags that are appropriate for regular files (all but dir-specific ones). */
> #define EXT4_REG_FLMASK (~(EXT4_DIRSYNC_FL | EXT4_TOPDIR_FL))
> @@ -434,6 +436,7 @@ enum {
> 	EXT4_INODE_EA_INODE	= 21,	/* Inode used for large EA */
> 	EXT4_INODE_EOFBLOCKS	= 22,	/* Blocks allocated beyond EOF */
> 	EXT4_INODE_INLINE_DATA	= 28,	/* Data in inode. */
> +	EXT4_INODE_PROJINHERIT	= 29,	/* Create with parents projid */
> 	EXT4_INODE_RESERVED	= 31,	/* reserved for ext4 lib */
> };
> 
> @@ -683,6 +686,7 @@ struct ext4_inode {
> 	__le32  i_crtime;       /* File Creation time */
> 	__le32  i_crtime_extra; /* extra FileCreationtime (nsec << 2 | epoch) */
> 	__le32  i_version_hi;	/* high 32 bits for 64-bit version */
> +	__le32  i_projid;	/* Project ID */
> };
> 
> struct move_extent {
> @@ -934,6 +938,7 @@ struct ext4_inode_info {
> 
> 	/* Precomputed uuid+inum+igen checksum for seeding inode checksums */
> 	__u32 i_csum_seed;
> +	kprojid_t i_projid;
> };
> 
> /*
> @@ -1518,6 +1523,7 @@ static inline void ext4_clear_state_flags(struct ext4_inode_info *ei)
>  * GDT_CSUM bits are mutually exclusive.
>  */
> #define EXT4_FEATURE_RO_COMPAT_METADATA_CSUM	0x0400
> +#define EXT4_FEATURE_RO_COMPAT_PROJECT		0x1000 /* Project quota */

I wonder if it makes sense to add EXT4_FEATURE_RO_COMPAT_METADATA_CSUM
here as well, to make it clear why this is skipping a value?

> #define EXT4_FEATURE_INCOMPAT_COMPRESSION	0x0001
> #define EXT4_FEATURE_INCOMPAT_FILETYPE		0x0002
> @@ -1567,7 +1573,8 @@ static inline void ext4_clear_state_flags(struct ext4_inode_info *ei)
> 					 EXT4_FEATURE_RO_COMPAT_HUGE_FILE |\
> 					 EXT4_FEATURE_RO_COMPAT_BIGALLOC |\
> 					 EXT4_FEATURE_RO_COMPAT_METADATA_CSUM|\
> -					 EXT4_FEATURE_RO_COMPAT_QUOTA)
> +					 EXT4_FEATURE_RO_COMPAT_QUOTA |\
> +					 EXT4_FEATURE_RO_COMPAT_PROJECT)
> 
> /*
>  * Default values for user and/or group using reserved blocks
> @@ -1575,6 +1582,11 @@ static inline void ext4_clear_state_flags(struct ext4_inode_info *ei)
> #define	EXT4_DEF_RESUID		0
> #define	EXT4_DEF_RESGID		0
> 
> +/*
> + * Default project ID
> + */
> +#define	EXT4_DEF_PROJID		0
> +
> #define EXT4_DEF_INODE_READAHEAD_BLKS	32
> 
> /*
> @@ -2131,6 +2143,7 @@ extern int ext4_zero_partial_blocks(handle_t *handle, struct inode *inode,
> 			     loff_t lstart, loff_t lend);
> extern int ext4_page_mkwrite(struct vm_area_struct *vma, struct vm_fault *vmf);
> extern qsize_t *ext4_get_reserved_space(struct inode *inode);
> +extern int ext4_get_projid(struct inode *inode, kprojid_t *projid);
> extern void ext4_da_update_reserve_space(struct inode *inode,
> 					int used, int quota_claim);
> 
> diff --git a/fs/ext4/ialloc.c b/fs/ext4/ialloc.c
> index ac644c3..fefb948 100644
> --- a/fs/ext4/ialloc.c
> +++ b/fs/ext4/ialloc.c
> @@ -756,6 +756,12 @@ struct inode *__ext4_new_inode(handle_t *handle, struct inode *dir,
> 		inode->i_gid = dir->i_gid;
> 	} else
> 		inode_init_owner(inode, dir, mode);
> +	if (EXT4_HAS_RO_COMPAT_FEATURE(sb, EXT4_FEATURE_RO_COMPAT_PROJECT) &&
> +	    ext4_test_inode_flag(dir, EXT4_INODE_PROJINHERIT)) {
> +		ei->i_projid = EXT4_I(dir)->i_projid;
> +	} else {
> +		ei->i_projid = make_kprojid(&init_user_ns, EXT4_DEF_PROJID);
> +	}

(style) no need for { } if only a single line in both if/else parts.

> 	dquot_initialize(inode);
> 
> 	if (!goal)
> diff --git a/fs/ext4/inode.c b/fs/ext4/inode.c
> index 5653fa4..29204d4 100644
> --- a/fs/ext4/inode.c
> +++ b/fs/ext4/inode.c
> @@ -3863,6 +3863,14 @@ static inline void ext4_iget_extra_inode(struct inode *inode,
> 		EXT4_I(inode)->i_inline_off = 0;
> }
> 
> +int ext4_get_projid(struct inode *inode, kprojid_t *projid)
> +{
> +	if (!EXT4_HAS_RO_COMPAT_FEATURE(inode->i_sb, EXT4_FEATURE_RO_COMPAT_PROJECT))
> +		return -EOPNOTSUPP;
> +	*projid = EXT4_I(inode)->i_projid;
> +	return 0;
> +}
> +
> struct inode *ext4_iget(struct super_block *sb, unsigned long ino)
> {
> 	struct ext4_iloc iloc;
> @@ -3874,6 +3882,7 @@ struct inode *ext4_iget(struct super_block *sb, unsigned long ino)
> 	int block;
> 	uid_t i_uid;
> 	gid_t i_gid;
> +	projid_t i_projid;
> 
> 	inode = iget_locked(sb, ino);
> 	if (!inode)
> @@ -3923,12 +3932,18 @@ struct inode *ext4_iget(struct super_block *sb, unsigned long ino)
> 	inode->i_mode = le16_to_cpu(raw_inode->i_mode);
> 	i_uid = (uid_t)le16_to_cpu(raw_inode->i_uid_low);
> 	i_gid = (gid_t)le16_to_cpu(raw_inode->i_gid_low);
> +	if (EXT4_HAS_RO_COMPAT_FEATURE(sb, EXT4_FEATURE_RO_COMPAT_PROJECT))
> +		i_projid = (projid_t)le32_to_cpu(raw_inode->i_projid);
> +	else
> +		i_projid = EXT4_DEF_PROJID;
> +
> 	if (!(test_opt(inode->i_sb, NO_UID32))) {
> 		i_uid |= le16_to_cpu(raw_inode->i_uid_high) << 16;
> 		i_gid |= le16_to_cpu(raw_inode->i_gid_high) << 16;
> 	}
> 	i_uid_write(inode, i_uid);
> 	i_gid_write(inode, i_gid);
> +	ei->i_projid = make_kprojid(&init_user_ns, i_projid);;
> 	set_nlink(inode, le16_to_cpu(raw_inode->i_links_count));
> 
> 	ext4_clear_state_flags(ei);	/* Only relevant on 32-bit archs */
> @@ -4158,6 +4173,7 @@ static int ext4_do_update_inode(handle_t *handle,
> 	int need_datasync = 0, set_large_file = 0;
> 	uid_t i_uid;
> 	gid_t i_gid;
> +	projid_t i_projid;
> 
> 	spin_lock(&ei->i_raw_lock);
> 
> @@ -4170,6 +4186,7 @@ static int ext4_do_update_inode(handle_t *handle,
> 	raw_inode->i_mode = cpu_to_le16(inode->i_mode);
> 	i_uid = i_uid_read(inode);
> 	i_gid = i_gid_read(inode);
> +	i_projid = from_kprojid(&init_user_ns, ei->i_projid);
> 	if (!(test_opt(inode->i_sb, NO_UID32))) {
> 		raw_inode->i_uid_low = cpu_to_le16(low_16_bits(i_uid));
> 		raw_inode->i_gid_low = cpu_to_le16(low_16_bits(i_gid));
> @@ -4249,6 +4266,18 @@ static int ext4_do_update_inode(handle_t *handle,
> 		}
> 	}
> 
> +	BUG_ON(!EXT4_HAS_RO_COMPAT_FEATURE(inode->i_sb,
> +			EXT4_FEATURE_RO_COMPAT_PROJECT) &&
> +	       i_projid != EXT4_DEF_PROJID);
> +	if (i_projid != EXT4_DEF_PROJID &&
> +	    (EXT4_INODE_SIZE(inode->i_sb) <= EXT4_GOOD_OLD_INODE_SIZE ||
> +	     (!EXT4_FITS_IN_INODE(raw_inode, ei, i_projid)))) {
> +		spin_unlock(&ei->i_raw_lock);
> +		err = -EFBIG;

I'm not sure if -EFBIG is the best error case, since that is a common
filesystem error.  Maybe -EOVERFLOW would be better?

Also, returning the error from ext4_mark_iloc_dirty->ext4_do_update_inode()
is a bit late in the game, since the inode has already been modified at
this point.  That callpath typically only returned an error if the disk
was bad or the journal aborted (again normally because the disk was bad),
so at that point the dirty in-memory data was lost anyway.

It would be better to check this in the caller before the inode is changed
so that an error can be returned without (essentially) corrupting the
in-memory state.  Since the projid should only be set for new inodes (which
will always have enough space, assuming RO_COMPAT_PROJECT cannot be set on
filesystems with 128-byte inodes), or in case of rename into a project
directory, it shouldn't be too big a change.

> +		goto out_brelse;
> +	}
> +	raw_inode->i_projid = cpu_to_le32(i_projid);
> +
> 	ext4_inode_csum_set(inode, raw_inode, ei);
> 
> 	spin_unlock(&ei->i_raw_lock);
> diff --git a/fs/ext4/namei.c b/fs/ext4/namei.c
> index 2291923..09e8e55 100644
> --- a/fs/ext4/namei.c
> +++ b/fs/ext4/namei.c
> @@ -2938,6 +2938,11 @@ static int ext4_link(struct dentry *old_dentry,
> 	if (inode->i_nlink >= EXT4_LINK_MAX)
> 		return -EMLINK;
> 
> +	if ((ext4_test_inode_flag(dir, EXT4_INODE_PROJINHERIT)) &&
> +	    (!projid_eq(EXT4_I(dir)->i_projid,
> +			EXT4_I(old_dentry->d_inode)->i_projid)))
> +		return -EXDEV;
> +
> 	dquot_initialize(dir);
> 
> retry:
> @@ -3217,6 +3222,11 @@ static int ext4_rename(struct inode *old_dir, struct dentry *old_dentry,
> 	int credits;
> 	u8 old_file_type;
> 
> +	if ((ext4_test_inode_flag(new_dir, EXT4_INODE_PROJINHERIT)) &&
> +	    (!projid_eq(EXT4_I(new_dir)->i_projid,
> +			EXT4_I(old_dentry->d_inode)->i_projid)))
> +		return -EXDEV;
> +
> 	dquot_initialize(old.dir);
> 	dquot_initialize(new.dir);
> 
> @@ -3395,6 +3405,13 @@ static int ext4_cross_rename(struct inode *old_dir, struct dentry *old_dentry,
> 	u8 new_file_type;
> 	int retval;
> 
> +	if ((ext4_test_inode_flag(new_dir, EXT4_INODE_PROJINHERIT)) &&
> +	    ((!projid_eq(EXT4_I(new_dir)->i_projid,
> +			 EXT4_I(old_dentry->d_inode)->i_projid)) ||
> +	     (!projid_eq(EXT4_I(old_dir)->i_projid,
> +			 EXT4_I(new_dentry->d_inode)->i_projid))))
> +		return -EXDEV;
> +
> 	dquot_initialize(old.dir);
> 	dquot_initialize(new.dir);
> 
> diff --git a/fs/ext4/super.c b/fs/ext4/super.c
> index 4fca81c..6b67795 100644
> --- a/fs/ext4/super.c
> +++ b/fs/ext4/super.c
> @@ -1067,6 +1067,7 @@ static const struct dquot_operations ext4_quota_operations = {
> 	.write_info	= ext4_write_info,
> 	.alloc_dquot	= dquot_alloc,
> 	.destroy_dquot	= dquot_destroy,
> +	.get_projid	= ext4_get_projid,
> };
> 
> static const struct quotactl_ops ext4_qctl_operations = {
> diff --git a/include/uapi/linux/fs.h b/include/uapi/linux/fs.h
> index 3735fa0..fcbf647 100644
> --- a/include/uapi/linux/fs.h
> +++ b/include/uapi/linux/fs.h
> @@ -195,6 +195,7 @@ struct inodes_stat_t {
> #define FS_EXTENT_FL			0x00080000 /* Extents */
> #define FS_DIRECTIO_FL			0x00100000 /* Use direct i/o */
> #define FS_NOCOW_FL			0x00800000 /* Do not cow file */
> +#define FS_PROJINHERIT_FL		0x20000000 /* Create with parents projid */
> #define FS_RESERVED_FL			0x80000000 /* reserved for ext2 lib */
> 
> #define FS_FL_USER_VISIBLE		0x0003DFFF /* User visible flags */
> -- 
> 1.7.1
> 


Cheers, Andreas





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