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

Dave Chinner
2016-02-08T04:24:33Z

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>
---
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