Re: [PATCH 3/9] xfs: cull unnecessary icdinode fields

Brian Foster
2016-02-08T15:29:28Z

On Mon, Feb 08, 2016 at 03:24:15PM +1100, Dave Chinner wrote:
> From: Dave Chinner <dchinner@redhat.com>
>
> Now that the struct xfs_icdinode is not directly related to the
> on-disk format, we can cull things in it we really don't need to
> store:
>
> - magic number never changes
> - padding is not necessary
> - next_unlinked is never used
> - inode number is redundant
> - uuid is redundant
> - lsn is accessed directly from dinode
> - inode CRC is only accessed directly from dinode
>
> Hence we can remove these from the struct xfs_icdinode and redirect
> the code that uses them to the xfs_dinode appripriately. This
> reduces the size of the struct icdinode from 152 bytes to 88 bytes,
> and removes a fair chunk of unnecessary code, too.
>
> Signed-off-by: Dave Chinner <dchinner@redhat.com>
> ---

Reviewed-by: Brian Foster <bfoster@redhat.com>

> fs/xfs/libxfs/xfs_inode_buf.c | 39 +++++++++++++--------------------------
> fs/xfs/libxfs/xfs_inode_buf.h | 25 ++++++-------------------
> fs/xfs/xfs_inode.c | 19 +------------------
> fs/xfs/xfs_inode_item.c | 19 +++++++++++--------
> 4 files changed, 31 insertions(+), 71 deletions(-)
>
> diff --git a/fs/xfs/libxfs/xfs_inode_buf.c b/fs/xfs/libxfs/xfs_inode_buf.c
> index 26e3c46..17ff4e8 100644
> --- a/fs/xfs/libxfs/xfs_inode_buf.c
> +++ b/fs/xfs/libxfs/xfs_inode_buf.c
> @@ -202,7 +202,6 @@ xfs_inode_from_disk(
> struct xfs_icdinode *to = &ip->i_d;
> struct inode *inode = VFS_I(ip);
>
> - to->di_magic = be16_to_cpu(from->di_magic);
> to->di_mode = be16_to_cpu(from->di_mode);
> to->di_version = from ->di_version;
> to->di_format = from->di_format;
> @@ -212,7 +211,6 @@ xfs_inode_from_disk(
> to->di_nlink = be32_to_cpu(from->di_nlink);
> to->di_projid_lo = be16_to_cpu(from->di_projid_lo);
> to->di_projid_hi = be16_to_cpu(from->di_projid_hi);
> - memcpy(to->di_pad, from->di_pad, sizeof(to->di_pad));
> to->di_flushiter = be16_to_cpu(from->di_flushiter);
>
> /*
> @@ -245,24 +243,22 @@ xfs_inode_from_disk(
> to->di_crtime.t_sec = be32_to_cpu(from->di_crtime.t_sec);
> to->di_crtime.t_nsec = be32_to_cpu(from->di_crtime.t_nsec);
> to->di_flags2 = be64_to_cpu(from->di_flags2);
> - to->di_ino = be64_to_cpu(from->di_ino);
> - to->di_lsn = be64_to_cpu(from->di_lsn);
> - memcpy(to->di_pad2, from->di_pad2, sizeof(to->di_pad2));
> - uuid_copy(&to->di_uuid, &from->di_uuid);
> }
> }
>
> void
> xfs_inode_to_disk(
> struct xfs_inode *ip,
> - struct xfs_dinode *to)
> + struct xfs_dinode *to,
> + xfs_lsn_t lsn)
> {
> struct xfs_icdinode *from = &ip->i_d;
> struct inode *inode = VFS_I(ip);
>
> - to->di_magic = cpu_to_be16(from->di_magic);
> + to->di_magic = cpu_to_be16(XFS_DINODE_MAGIC);
> +
> to->di_mode = cpu_to_be16(from->di_mode);
> - to->di_version = from ->di_version;
> + to->di_version = from->di_version;
> to->di_format = from->di_format;
> to->di_onlink = cpu_to_be16(from->di_onlink);
> to->di_uid = cpu_to_be32(from->di_uid);
> @@ -270,8 +266,8 @@ xfs_inode_to_disk(
> to->di_nlink = cpu_to_be32(from->di_nlink);
> to->di_projid_lo = cpu_to_be16(from->di_projid_lo);
> to->di_projid_hi = cpu_to_be16(from->di_projid_hi);
> - memcpy(to->di_pad, from->di_pad, sizeof(to->di_pad));
>
> + memset(to->di_pad, 0, sizeof(to->di_pad));
> to->di_atime.t_sec = cpu_to_be32(inode->i_atime.tv_sec);
> to->di_atime.t_nsec = cpu_to_be32(inode->i_atime.tv_nsec);
> to->di_mtime.t_sec = cpu_to_be32(inode->i_mtime.tv_sec);
> @@ -296,10 +292,11 @@ xfs_inode_to_disk(
> to->di_crtime.t_sec = cpu_to_be32(from->di_crtime.t_sec);
> to->di_crtime.t_nsec = cpu_to_be32(from->di_crtime.t_nsec);
> to->di_flags2 = cpu_to_be64(from->di_flags2);
> - to->di_ino = cpu_to_be64(from->di_ino);
> - to->di_lsn = cpu_to_be64(from->di_lsn);
> - memcpy(to->di_pad2, from->di_pad2, sizeof(to->di_pad2));
> - uuid_copy(&to->di_uuid, &from->di_uuid);
> +
> + to->di_ino = cpu_to_be64(ip->i_ino);
> + to->di_lsn = cpu_to_be64(lsn);
> + memset(to->di_pad2, 0, sizeof(to->di_pad2));
> + uuid_copy(&to->di_uuid, &ip->i_mount->m_sb.sb_meta_uuid);
> to->di_flushiter = 0;
> } else {
> to->di_flushiter = cpu_to_be16(from->di_flushiter);
> @@ -434,13 +431,10 @@ xfs_iread(
> !(mp->m_flags & XFS_MOUNT_IKEEP)) {
> /* initialise the on-disk inode core */
> memset(&ip->i_d, 0, sizeof(ip->i_d));
> - ip->i_d.di_magic = XFS_DINODE_MAGIC;
> ip->i_d.di_gen = prandom_u32();
> - if (xfs_sb_version_hascrc(&mp->m_sb)) {
> + if (xfs_sb_version_hascrc(&mp->m_sb))
> ip->i_d.di_version = 3;
> - ip->i_d.di_ino = ip->i_ino;
> - uuid_copy(&ip->i_d.di_uuid, &mp->m_sb.sb_meta_uuid);
> - } else
> + else
> ip->i_d.di_version = 2;
> return 0;
> }
> @@ -484,16 +478,10 @@ xfs_iread(
> * Partial initialisation of the in-core inode. Just the bits
> * that xfs_ialloc won't overwrite or relies on being correct.
> */
> - ip->i_d.di_magic = be16_to_cpu(dip->di_magic);
> ip->i_d.di_version = dip->di_version;
> ip->i_d.di_gen = be32_to_cpu(dip->di_gen);
> ip->i_d.di_flushiter = be16_to_cpu(dip->di_flushiter);
>
> - if (dip->di_version == 3) {
> - ip->i_d.di_ino = be64_to_cpu(dip->di_ino);
> - uuid_copy(&ip->i_d.di_uuid, &dip->di_uuid);
> - }
> -
> /*
> * Make sure to pull in the mode here as well in
> * case the inode is released without being used.
> @@ -514,7 +502,6 @@ xfs_iread(
> */
> if (ip->i_d.di_version == 1) {
> ip->i_d.di_version = 2;
> - memset(&(ip->i_d.di_pad[0]), 0, sizeof(ip->i_d.di_pad));
> ip->i_d.di_nlink = ip->i_d.di_onlink;
> ip->i_d.di_onlink = 0;
> xfs_set_projid(ip, 0);
> diff --git a/fs/xfs/libxfs/xfs_inode_buf.h b/fs/xfs/libxfs/xfs_inode_buf.h
> index adcc9bf..7b8b1b9 100644
> --- a/fs/xfs/libxfs/xfs_inode_buf.h
> +++ b/fs/xfs/libxfs/xfs_inode_buf.h
> @@ -22,24 +22,22 @@ struct xfs_inode;
> struct xfs_dinode;
>
> /*
> - * In memory representation of the XFS inode. This is held in the in-core
> - * struct xfs_inode to represent the on disk values, but no longer needs to be
> - * identical to the on-disk structure as it is always translated to on-disk
> + * In memory representation of the XFS inode. This is held in the in-core struct
> + * xfs_inode and represents the current on disk values but the structure is not
> + * in on-disk format. That is, this structure is always translated to on-disk
> * format specific structures at the appropriate time.
> */
> struct xfs_icdinode {
> - __uint16_t di_magic; /* inode magic # = XFS_DINODE_MAGIC */
> __uint16_t di_mode; /* mode and type of file */
> __int8_t di_version; /* inode version */
> __int8_t di_format; /* format of di_c data */
> __uint16_t di_onlink; /* old number of links to file */
> + __uint16_t di_flushiter; /* incremented on flush */
> __uint32_t di_uid; /* owner's user id */
> __uint32_t di_gid; /* owner's group id */
> __uint32_t di_nlink; /* number of links to file */
> __uint16_t di_projid_lo; /* lower part of owner's project id */
> __uint16_t di_projid_hi; /* higher part of owner's project id */
> - __uint8_t di_pad[6]; /* unused, zeroed space */
> - __uint16_t di_flushiter; /* incremented on flush */
> xfs_fsize_t di_size; /* number of bytes in file */
> xfs_rfsblock_t di_nblocks; /* # of direct & btree blocks used */
> xfs_extlen_t di_extsize; /* basic/minimum extent size for file */
> @@ -52,22 +50,10 @@ struct xfs_icdinode {
> __uint16_t di_flags; /* random flags, XFS_DIFLAG_... */
> __uint32_t di_gen; /* generation number */
>
> - /* di_next_unlinked is the only non-core field in the old dinode */
> - xfs_agino_t di_next_unlinked;/* agi unlinked list ptr */
> -
> - /* start of the extended dinode, writable fields */
> - __uint32_t di_crc; /* CRC of the inode */
> __uint64_t di_changecount; /* number of attribute changes */
> - xfs_lsn_t di_lsn; /* flush sequence */
> __uint64_t di_flags2; /* more random flags */
> - __uint8_t di_pad2[16]; /* more padding for future expansion */
>
> - /* fields only written to during inode creation */
> xfs_ictimestamp_t di_crtime; /* time created */
> - xfs_ino_t di_ino; /* inode number */
> - uuid_t di_uuid; /* UUID of the filesystem */
> -
> - /* structure must be padded to 64 bit alignment */
> };
>
> /*
> @@ -86,7 +72,8 @@ int xfs_imap_to_bp(struct xfs_mount *, struct xfs_trans *,
> int xfs_iread(struct xfs_mount *, struct xfs_trans *,
> struct xfs_inode *, uint);
> void xfs_dinode_calc_crc(struct xfs_mount *, struct xfs_dinode *);
> -void xfs_inode_to_disk(struct xfs_inode *ip, struct xfs_dinode *to);
> +void xfs_inode_to_disk(struct xfs_inode *ip, struct xfs_dinode *to,
> + xfs_lsn_t lsn);
> void xfs_inode_from_disk(struct xfs_inode *ip, struct xfs_dinode *from);
> void xfs_log_dinode_to_disk(struct xfs_log_dinode *from,
> struct xfs_dinode *to);
> diff --git a/fs/xfs/xfs_inode.c b/fs/xfs/xfs_inode.c
> index 9ad9e35..45acdee 100644
> --- a/fs/xfs/xfs_inode.c
> +++ b/fs/xfs/xfs_inode.c
> @@ -809,7 +809,6 @@ xfs_ialloc(
> ip->i_d.di_uid = xfs_kuid_to_uid(current_fsuid());
> ip->i_d.di_gid = xfs_kgid_to_gid(current_fsgid());
> xfs_set_projid(ip, prid);
> - memset(&(ip->i_d.di_pad[0]), 0, sizeof(ip->i_d.di_pad));
>
> if (pip && XFS_INHERIT_GID(pip)) {
> ip->i_d.di_gid = pip->i_d.di_gid;
> @@ -847,13 +846,8 @@ xfs_ialloc(
> ip->i_d.di_flags = 0;
>
> if (ip->i_d.di_version == 3) {
> - ASSERT(ip->i_d.di_ino == ino);
> - ASSERT(uuid_equal(&ip->i_d.di_uuid, &mp->m_sb.sb_meta_uuid));
> - ip->i_d.di_crc = 0;
> ip->i_d.di_changecount = 1;
> - ip->i_d.di_lsn = 0;
> ip->i_d.di_flags2 = 0;
> - memset(&(ip->i_d.di_pad2[0]), 0, sizeof(ip->i_d.di_pad2));
> ip->i_d.di_crtime.t_sec = (__int32_t)tv.tv_sec;
> ip->i_d.di_crtime.t_nsec = (__int32_t)tv.tv_nsec;
> }
> @@ -3464,13 +3458,6 @@ xfs_iflush_int(
> __func__, ip->i_ino, be16_to_cpu(dip->di_magic), dip);
> goto corrupt_out;
> }
> - if (XFS_TEST_ERROR(ip->i_d.di_magic != XFS_DINODE_MAGIC,
> - mp, XFS_ERRTAG_IFLUSH_2, XFS_RANDOM_IFLUSH_2)) {
> - xfs_alert_tag(mp, XFS_PTAG_IFLUSH,
> - "%s: Bad inode %Lu, ptr 0x%p, magic number 0x%x",
> - __func__, ip->i_ino, ip, ip->i_d.di_magic);
> - goto corrupt_out;
> - }
> if (S_ISREG(ip->i_d.di_mode)) {
> if (XFS_TEST_ERROR(
> (ip->i_d.di_format != XFS_DINODE_FMT_EXTENTS) &&
> @@ -3529,7 +3516,7 @@ xfs_iflush_int(
> * copy out the core of the inode, because if the inode is dirty at all
> * the core must be.
> */
> - xfs_inode_to_disk(ip, dip);
> + xfs_inode_to_disk(ip, dip, iip->ili_item.li_lsn);
>
> /* Wrap, we never let the log put out DI_MAX_FLUSH */
> if (ip->i_d.di_flushiter == DI_MAX_FLUSH)
> @@ -3581,10 +3568,6 @@ xfs_iflush_int(
> */
> xfs_buf_attach_iodone(bp, xfs_iflush_done, &iip->ili_item);
>
> - /* update the lsn in the on disk inode if required */
> - if (ip->i_d.di_version == 3)
> - dip->di_lsn = cpu_to_be64(iip->ili_item.li_lsn);
> -
> /* generate the checksum. */
> xfs_dinode_calc_crc(mp, dip);
>
> diff --git a/fs/xfs/xfs_inode_item.c b/fs/xfs/xfs_inode_item.c
> index 9dcbf58..588d1b4 100644
> --- a/fs/xfs/xfs_inode_item.c
> +++ b/fs/xfs/xfs_inode_item.c
> @@ -325,12 +325,14 @@ xfs_inode_item_format_attr_fork(
> static void
> xfs_inode_to_log_dinode(
> struct xfs_inode *ip,
> - struct xfs_log_dinode *to)
> + struct xfs_log_dinode *to,
> + xfs_lsn_t lsn)
> {
> struct xfs_icdinode *from = &ip->i_d;
> struct inode *inode = VFS_I(ip);
>
> - to->di_magic = from->di_magic;
> + to->di_magic = XFS_DINODE_MAGIC;
> +
> to->di_mode = from->di_mode;
> to->di_version = from->di_version;
> to->di_format = from->di_format;
> @@ -340,8 +342,8 @@ xfs_inode_to_log_dinode(
> to->di_nlink = from->di_nlink;
> to->di_projid_lo = from->di_projid_lo;
> to->di_projid_hi = from->di_projid_hi;
> - memcpy(to->di_pad, from->di_pad, sizeof(to->di_pad));
>
> + memset(to->di_pad, 0, sizeof(to->di_pad));
> to->di_atime.t_sec = inode->i_atime.tv_sec;
> to->di_atime.t_nsec = inode->i_atime.tv_nsec;
> to->di_mtime.t_sec = inode->i_mtime.tv_sec;
> @@ -366,10 +368,11 @@ xfs_inode_to_log_dinode(
> to->di_crtime.t_sec = from->di_crtime.t_sec;
> to->di_crtime.t_nsec = from->di_crtime.t_nsec;
> to->di_flags2 = from->di_flags2;
> - to->di_ino = from->di_ino;
> - to->di_lsn = from->di_lsn;
> - memcpy(to->di_pad2, from->di_pad2, sizeof(to->di_pad2));
> - uuid_copy(&to->di_uuid, &from->di_uuid);
> +
> + to->di_ino = ip->i_ino;
> + to->di_lsn = lsn;
> + memset(to->di_pad2, 0, sizeof(to->di_pad2));
> + uuid_copy(&to->di_uuid, &ip->i_mount->m_sb.sb_meta_uuid);
> to->di_flushiter = 0;
> } else {
> to->di_flushiter = from->di_flushiter;
> @@ -390,7 +393,7 @@ xfs_inode_item_format_core(
> struct xfs_log_dinode *dic;
>
> dic = xlog_prepare_iovec(lv, vecp, XLOG_REG_TYPE_ICORE);
> - xfs_inode_to_log_dinode(ip, dic);
> + xfs_inode_to_log_dinode(ip, dic, ip->i_itemp->ili_item.li_lsn);
> xlog_finish_iovec(lv, *vecp, xfs_log_dinode_size(ip->i_d.di_version));
> }
>
> --
> 2.5.0
>
> _______________________________________________
> xfs mailing list
> xfs@oss.sgi.com
> http://oss.sgi.com/mailman/listinfo/xfs