Re: [PATCH 14/49] xfs: introduce xfs_inode_buf.c for inode buffer operations

[Brian Foster <bfoster@redhat.com>]

On 07/19/2013 02:24 AM, Dave Chinner wrote:
> From: Dave Chinner <dchinner@redhat.com>
> 
> The only thing remaining in xfs_inode.[ch] are the operations that
> read, write or verify physical inodes in their underlying buffers.
> Move all this code to xfs_inode_buf.[ch] and so we can stop sharing
> xfs_inode.[ch] with userspace.
> 
> Signed-off-by: Dave Chinner <dchinner@redhat.com>
> ---

I noticed Mark mentioned something about this being stale. That aside, I
see some whitespace fixups and a clean move otherwise:

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

>  fs/xfs/Makefile        |   1 +
>  fs/xfs/xfs_inode.c     | 413 ---------------------------------------------
>  fs/xfs/xfs_inode.h     |  41 +----
>  fs/xfs/xfs_inode_buf.c | 444 +++++++++++++++++++++++++++++++++++++++++++++++++
>  fs/xfs/xfs_inode_buf.h |  53 ++++++
>  5 files changed, 505 insertions(+), 447 deletions(-)
>  create mode 100644 fs/xfs/xfs_inode_buf.c
>  create mode 100644 fs/xfs/xfs_inode_buf.h
> 
> diff --git a/fs/xfs/Makefile b/fs/xfs/Makefile
> index ce0b87e..7f2319d 100644
> --- a/fs/xfs/Makefile
> +++ b/fs/xfs/Makefile
> @@ -75,6 +75,7 @@ xfs-y				+= xfs_alloc.o \
>  				   xfs_icreate_item.o \
>  				   xfs_inode.o \
>  				   xfs_inode_fork.o \
> +				   xfs_inode_buf.o \
>  				   xfs_log_recover.o \
>  				   xfs_mount.o \
>  				   xfs_symlink.o \
> diff --git a/fs/xfs/xfs_inode.c b/fs/xfs/xfs_inode.c
> index 51e4eb2..cf35d86 100644
> --- a/fs/xfs/xfs_inode.c
> +++ b/fs/xfs/xfs_inode.c
> @@ -322,234 +322,6 @@ __xfs_iflock(
>  	finish_wait(wq, &wait.wait);
>  }
>  
> -/*
> - * Check that none of the inode's in the buffer have a next
> - * unlinked field of 0.
> - */
> -#if defined(DEBUG)
> -void
> -xfs_inobp_check(
> -	xfs_mount_t	*mp,
> -	xfs_buf_t	*bp)
> -{
> -	int		i;
> -	int		j;
> -	xfs_dinode_t	*dip;
> -
> -	j = mp->m_inode_cluster_size >> mp->m_sb.sb_inodelog;
> -
> -	for (i = 0; i < j; i++) {
> -		dip = (xfs_dinode_t *)xfs_buf_offset(bp,
> -					i * mp->m_sb.sb_inodesize);
> -		if (!dip->di_next_unlinked)  {
> -			xfs_alert(mp,
> -	"Detected bogus zero next_unlinked field in incore inode buffer 0x%p.",
> -				bp);
> -			ASSERT(dip->di_next_unlinked);
> -		}
> -	}
> -}
> -#endif
> -
> -static void
> -xfs_inode_buf_verify(
> -	struct xfs_buf	*bp)
> -{
> -	struct xfs_mount *mp = bp->b_target->bt_mount;
> -	int		i;
> -	int		ni;
> -
> -	/*
> -	 * Validate the magic number and version of every inode in the buffer
> -	 */
> -	ni = XFS_BB_TO_FSB(mp, bp->b_length) * mp->m_sb.sb_inopblock;
> -	for (i = 0; i < ni; i++) {
> -		int		di_ok;
> -		xfs_dinode_t	*dip;
> -
> -		dip = (struct xfs_dinode *)xfs_buf_offset(bp,
> -					(i << mp->m_sb.sb_inodelog));
> -		di_ok = dip->di_magic == cpu_to_be16(XFS_DINODE_MAGIC) &&
> -			    XFS_DINODE_GOOD_VERSION(dip->di_version);
> -		if (unlikely(XFS_TEST_ERROR(!di_ok, mp,
> -						XFS_ERRTAG_ITOBP_INOTOBP,
> -						XFS_RANDOM_ITOBP_INOTOBP))) {
> -			xfs_buf_ioerror(bp, EFSCORRUPTED);
> -			XFS_CORRUPTION_ERROR(__func__, XFS_ERRLEVEL_HIGH,
> -					     mp, dip);
> -#ifdef DEBUG
> -			xfs_emerg(mp,
> -				"bad inode magic/vsn daddr %lld #%d (magic=%x)",
> -				(unsigned long long)bp->b_bn, i,
> -				be16_to_cpu(dip->di_magic));
> -			ASSERT(0);
> -#endif
> -		}
> -	}
> -	xfs_inobp_check(mp, bp);
> -}
> -
> -
> -static void
> -xfs_inode_buf_read_verify(
> -	struct xfs_buf	*bp)
> -{
> -	xfs_inode_buf_verify(bp);
> -}
> -
> -static void
> -xfs_inode_buf_write_verify(
> -	struct xfs_buf	*bp)
> -{
> -	xfs_inode_buf_verify(bp);
> -}
> -
> -const struct xfs_buf_ops xfs_inode_buf_ops = {
> -	.verify_read = xfs_inode_buf_read_verify,
> -	.verify_write = xfs_inode_buf_write_verify,
> -};
> -
> -
> -/*
> - * This routine is called to map an inode to the buffer containing the on-disk
> - * version of the inode.  It returns a pointer to the buffer containing the
> - * on-disk inode in the bpp parameter, and in the dipp parameter it returns a
> - * pointer to the on-disk inode within that buffer.
> - *
> - * If a non-zero error is returned, then the contents of bpp and dipp are
> - * undefined.
> - */
> -int
> -xfs_imap_to_bp(
> -	struct xfs_mount	*mp,
> -	struct xfs_trans	*tp,
> -	struct xfs_imap		*imap,
> -	struct xfs_dinode       **dipp,
> -	struct xfs_buf		**bpp,
> -	uint			buf_flags,
> -	uint			iget_flags)
> -{
> -	struct xfs_buf		*bp;
> -	int			error;
> -
> -	buf_flags |= XBF_UNMAPPED;
> -	error = xfs_trans_read_buf(mp, tp, mp->m_ddev_targp, imap->im_blkno,
> -				   (int)imap->im_len, buf_flags, &bp,
> -				   &xfs_inode_buf_ops);
> -	if (error) {
> -		if (error == EAGAIN) {
> -			ASSERT(buf_flags & XBF_TRYLOCK);
> -			return error;
> -		}
> -
> -		if (error == EFSCORRUPTED &&
> -		    (iget_flags & XFS_IGET_UNTRUSTED))
> -			return XFS_ERROR(EINVAL);
> -
> -		xfs_warn(mp, "%s: xfs_trans_read_buf() returned error %d.",
> -			__func__, error);
> -		return error;
> -	}
> -
> -	*bpp = bp;
> -	*dipp = (struct xfs_dinode *)xfs_buf_offset(bp, imap->im_boffset);
> -	return 0;
> -}
> -
> -STATIC void
> -xfs_dinode_from_disk(
> -	xfs_icdinode_t		*to,
> -	xfs_dinode_t		*from)
> -{
> -	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;
> -	to->di_onlink = be16_to_cpu(from->di_onlink);
> -	to->di_uid = be32_to_cpu(from->di_uid);
> -	to->di_gid = be32_to_cpu(from->di_gid);
> -	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);
> -	to->di_atime.t_sec = be32_to_cpu(from->di_atime.t_sec);
> -	to->di_atime.t_nsec = be32_to_cpu(from->di_atime.t_nsec);
> -	to->di_mtime.t_sec = be32_to_cpu(from->di_mtime.t_sec);
> -	to->di_mtime.t_nsec = be32_to_cpu(from->di_mtime.t_nsec);
> -	to->di_ctime.t_sec = be32_to_cpu(from->di_ctime.t_sec);
> -	to->di_ctime.t_nsec = be32_to_cpu(from->di_ctime.t_nsec);
> -	to->di_size = be64_to_cpu(from->di_size);
> -	to->di_nblocks = be64_to_cpu(from->di_nblocks);
> -	to->di_extsize = be32_to_cpu(from->di_extsize);
> -	to->di_nextents = be32_to_cpu(from->di_nextents);
> -	to->di_anextents = be16_to_cpu(from->di_anextents);
> -	to->di_forkoff = from->di_forkoff;
> -	to->di_aformat	= from->di_aformat;
> -	to->di_dmevmask	= be32_to_cpu(from->di_dmevmask);
> -	to->di_dmstate	= be16_to_cpu(from->di_dmstate);
> -	to->di_flags	= be16_to_cpu(from->di_flags);
> -	to->di_gen	= be32_to_cpu(from->di_gen);
> -
> -	if (to->di_version == 3) {
> -		to->di_changecount = be64_to_cpu(from->di_changecount);
> -		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_dinode_to_disk(
> -	xfs_dinode_t		*to,
> -	xfs_icdinode_t		*from)
> -{
> -	to->di_magic = cpu_to_be16(from->di_magic);
> -	to->di_mode = cpu_to_be16(from->di_mode);
> -	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);
> -	to->di_gid = cpu_to_be32(from->di_gid);
> -	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));
> -	to->di_flushiter = cpu_to_be16(from->di_flushiter);
> -	to->di_atime.t_sec = cpu_to_be32(from->di_atime.t_sec);
> -	to->di_atime.t_nsec = cpu_to_be32(from->di_atime.t_nsec);
> -	to->di_mtime.t_sec = cpu_to_be32(from->di_mtime.t_sec);
> -	to->di_mtime.t_nsec = cpu_to_be32(from->di_mtime.t_nsec);
> -	to->di_ctime.t_sec = cpu_to_be32(from->di_ctime.t_sec);
> -	to->di_ctime.t_nsec = cpu_to_be32(from->di_ctime.t_nsec);
> -	to->di_size = cpu_to_be64(from->di_size);
> -	to->di_nblocks = cpu_to_be64(from->di_nblocks);
> -	to->di_extsize = cpu_to_be32(from->di_extsize);
> -	to->di_nextents = cpu_to_be32(from->di_nextents);
> -	to->di_anextents = cpu_to_be16(from->di_anextents);
> -	to->di_forkoff = from->di_forkoff;
> -	to->di_aformat = from->di_aformat;
> -	to->di_dmevmask = cpu_to_be32(from->di_dmevmask);
> -	to->di_dmstate = cpu_to_be16(from->di_dmstate);
> -	to->di_flags = cpu_to_be16(from->di_flags);
> -	to->di_gen = cpu_to_be32(from->di_gen);
> -
> -	if (from->di_version == 3) {
> -		to->di_changecount = cpu_to_be64(from->di_changecount);
> -		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);
> -	}
> -}
> -
>  STATIC uint
>  _xfs_dic2xflags(
>  	__uint16_t		di_flags)
> @@ -608,191 +380,6 @@ xfs_dic2xflags(
>  				(XFS_DFORK_Q(dip) ? XFS_XFLAG_HASATTR : 0);
>  }
>  
> -static bool
> -xfs_dinode_verify(
> -	struct xfs_mount	*mp,
> -	struct xfs_inode	*ip,
> -	struct xfs_dinode	*dip)
> -{
> -	if (dip->di_magic != cpu_to_be16(XFS_DINODE_MAGIC))
> -		return false;
> -
> -	/* only version 3 or greater inodes are extensively verified here */
> -	if (dip->di_version < 3)
> -		return true;
> -
> -	if (!xfs_sb_version_hascrc(&mp->m_sb))
> -		return false;
> -	if (!xfs_verify_cksum((char *)dip, mp->m_sb.sb_inodesize,
> -			      offsetof(struct xfs_dinode, di_crc)))
> -		return false;
> -	if (be64_to_cpu(dip->di_ino) != ip->i_ino)
> -		return false;
> -	if (!uuid_equal(&dip->di_uuid, &mp->m_sb.sb_uuid))
> -		return false;
> -	return true;
> -}
> -
> -void
> -xfs_dinode_calc_crc(
> -	struct xfs_mount	*mp,
> -	struct xfs_dinode	*dip)
> -{
> -	__uint32_t		crc;
> -
> -	if (dip->di_version < 3)
> -		return;
> -
> -	ASSERT(xfs_sb_version_hascrc(&mp->m_sb));
> -	crc = xfs_start_cksum((char *)dip, mp->m_sb.sb_inodesize,
> -			      offsetof(struct xfs_dinode, di_crc));
> -	dip->di_crc = xfs_end_cksum(crc);
> -}
> -
> -/*
> - * Read the disk inode attributes into the in-core inode structure.
> - *
> - * If we are initialising a new inode and we are not utilising the
> - * XFS_MOUNT_IKEEP inode cluster mode, we can simple build the new inode core
> - * with a random generation number. If we are keeping inodes around, we need to
> - * read the inode cluster to get the existing generation number off disk.
> - */
> -int
> -xfs_iread(
> -	xfs_mount_t	*mp,
> -	xfs_trans_t	*tp,
> -	xfs_inode_t	*ip,
> -	uint		iget_flags)
> -{
> -	xfs_buf_t	*bp;
> -	xfs_dinode_t	*dip;
> -	int		error;
> -
> -	/*
> -	 * Fill in the location information in the in-core inode.
> -	 */
> -	error = xfs_imap(mp, tp, ip->i_ino, &ip->i_imap, iget_flags);
> -	if (error)
> -		return error;
> -
> -	/* shortcut IO on inode allocation if possible */
> -	if ((iget_flags & XFS_IGET_CREATE) &&
> -	    !(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)) {
> -			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_uuid);
> -		} else
> -			ip->i_d.di_version = 2;
> -		return 0;
> -	}
> -
> -	/*
> -	 * Get pointers to the on-disk inode and the buffer containing it.
> -	 */
> -	error = xfs_imap_to_bp(mp, tp, &ip->i_imap, &dip, &bp, 0, iget_flags);
> -	if (error)
> -		return error;
> -
> -	/* even unallocated inodes are verified */
> -	if (!xfs_dinode_verify(mp, ip, dip)) {
> -		xfs_alert(mp, "%s: validation failed for inode %lld failed",
> -				__func__, ip->i_ino);
> -
> -		XFS_CORRUPTION_ERROR(__func__, XFS_ERRLEVEL_LOW, mp, dip);
> -		error = XFS_ERROR(EFSCORRUPTED);
> -		goto out_brelse;
> -	}
> -
> -	/*
> -	 * If the on-disk inode is already linked to a directory
> -	 * entry, copy all of the inode into the in-core inode.
> -	 * xfs_iformat_fork() handles copying in the inode format
> -	 * specific information.
> -	 * Otherwise, just get the truly permanent information.
> -	 */
> -	if (dip->di_mode) {
> -		xfs_dinode_from_disk(&ip->i_d, dip);
> -		error = xfs_iformat_fork(ip, dip);
> -		if (error)  {
> -#ifdef DEBUG
> -			xfs_alert(mp, "%s: xfs_iformat() returned error %d",
> -				__func__, error);
> -#endif /* DEBUG */
> -			goto out_brelse;
> -		}
> -	} else {
> -		/*
> -		 * 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.
> -		 * This ensures that xfs_inactive() will see that
> -		 * the inode is already free and not try to mess
> -		 * with the uninitialized part of it.
> -		 */
> -		ip->i_d.di_mode = 0;
> -	}
> -
> -	/*
> -	 * The inode format changed when we moved the link count and
> -	 * made it 32 bits long.  If this is an old format inode,
> -	 * convert it in memory to look like a new one.  If it gets
> -	 * flushed to disk we will convert back before flushing or
> -	 * logging it.  We zero out the new projid field and the old link
> -	 * count field.  We'll handle clearing the pad field (the remains
> -	 * of the old uuid field) when we actually convert the inode to
> -	 * the new format. We don't change the version number so that we
> -	 * can distinguish this from a real new format inode.
> -	 */
> -	if (ip->i_d.di_version == 1) {
> -		ip->i_d.di_nlink = ip->i_d.di_onlink;
> -		ip->i_d.di_onlink = 0;
> -		xfs_set_projid(ip, 0);
> -	}
> -
> -	ip->i_delayed_blks = 0;
> -
> -	/*
> -	 * Mark the buffer containing the inode as something to keep
> -	 * around for a while.  This helps to keep recently accessed
> -	 * meta-data in-core longer.
> -	 */
> -	xfs_buf_set_ref(bp, XFS_INO_REF);
> -
> -	/*
> -	 * Use xfs_trans_brelse() to release the buffer containing the on-disk
> -	 * inode, because it was acquired with xfs_trans_read_buf() in
> -	 * xfs_imap_to_bp() above.  If tp is NULL, this is just a normal
> -	 * brelse().  If we're within a transaction, then xfs_trans_brelse()
> -	 * will only release the buffer if it is not dirty within the
> -	 * transaction.  It will be OK to release the buffer in this case,
> -	 * because inodes on disk are never destroyed and we will be locking the
> -	 * new in-core inode before putting it in the cache where other
> -	 * processes can find it.  Thus we don't have to worry about the inode
> -	 * being changed just because we released the buffer.
> -	 */
> - out_brelse:
> -	xfs_trans_brelse(tp, bp);
> -	return error;
> -}
> -
>  /*
>   * Allocate an inode on disk and return a copy of its in-core version.
>   * The in-core inode is locked exclusively.  Set mode, nlink, and rdev
> diff --git a/fs/xfs/xfs_inode.h b/fs/xfs/xfs_inode.h
> index 0bd034a..8f775ed 100644
> --- a/fs/xfs/xfs_inode.h
> +++ b/fs/xfs/xfs_inode.h
> @@ -18,24 +18,15 @@
>  #ifndef	__XFS_INODE_H__
>  #define	__XFS_INODE_H__
>  
> -struct posix_acl;
> -struct xfs_dinode;
> -struct xfs_inode;
> -
> +#include "xfs_inode_buf.h"
>  #include "xfs_inode_fork.h"
>  
>  /*
> - * Inode location information.  Stored in the inode and passed to
> - * xfs_imap_to_bp() to get a buffer and dinode for a given inode.
> + * Kernel only inode definitions
>   */
> -struct xfs_imap {
> -	xfs_daddr_t	im_blkno;	/* starting BB of inode chunk */
> -	ushort		im_len;		/* length in BBs of inode chunk */
> -	ushort		im_boffset;	/* inode offset in block in bytes */
> -};
> -
> -#ifdef __KERNEL__
>  
> +struct xfs_dinode;
> +struct xfs_inode;
>  struct xfs_buf;
>  struct xfs_bmap_free;
>  struct xfs_bmbt_irec;
> @@ -347,7 +338,10 @@ int		xfs_itruncate_extents(struct xfs_trans **, struct xfs_inode *,
>  int		xfs_iunlink(struct xfs_trans *, xfs_inode_t *);
>  
>  void		xfs_iext_realloc(xfs_inode_t *, int, int);
> +
>  void		xfs_iunpin_wait(xfs_inode_t *);
> +#define xfs_ipincount(ip)	((unsigned int) atomic_read(&ip->i_pincount))
> +
>  int		xfs_iflush(struct xfs_inode *, struct xfs_buf **);
>  void		xfs_lock_inodes(xfs_inode_t **, int, uint);
>  void		xfs_lock_two_inodes(xfs_inode_t *, xfs_inode_t *, uint);
> @@ -367,27 +361,6 @@ do { \
>  	iput(VFS_I(ip)); \
>  } while (0)
>  
> -#endif /* __KERNEL__ */
> -
> -int		xfs_imap_to_bp(struct xfs_mount *, struct xfs_trans *,
> -			       struct xfs_imap *, struct xfs_dinode **,
> -			       struct xfs_buf **, uint, uint);
> -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_dinode_to_disk(struct xfs_dinode *,
> -				   struct xfs_icdinode *);
> -bool		xfs_can_free_eofblocks(struct xfs_inode *, bool);
> -
> -#define xfs_ipincount(ip)	((unsigned int) atomic_read(&ip->i_pincount))
> -
> -#if defined(DEBUG)
> -void		xfs_inobp_check(struct xfs_mount *, struct xfs_buf *);
> -#else
> -#define	xfs_inobp_check(mp, bp)
> -#endif /* DEBUG */
> -
>  extern struct kmem_zone	*xfs_inode_zone;
> -extern const struct xfs_buf_ops xfs_inode_buf_ops;
>  
>  #endif	/* __XFS_INODE_H__ */
> diff --git a/fs/xfs/xfs_inode_buf.c b/fs/xfs/xfs_inode_buf.c
> new file mode 100644
> index 0000000..4abbaf3
> --- /dev/null
> +++ b/fs/xfs/xfs_inode_buf.c
> @@ -0,0 +1,444 @@
> +/*
> + * Copyright (c) 2000-2006 Silicon Graphics, Inc.
> + * All Rights Reserved.
> + *
> + * This program is free software; you can redistribute it and/or
> + * modify it under the terms of the GNU General Public License as
> + * published by the Free Software Foundation.
> + *
> + * This program is distributed in the hope that it would be useful,
> + * but WITHOUT ANY WARRANTY; without even the implied warranty of
> + * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
> + * GNU General Public License for more details.
> + *
> + * You should have received a copy of the GNU General Public License
> + * along with this program; if not, write the Free Software Foundation,
> + * Inc.,  51 Franklin St, Fifth Floor, Boston, MA  02110-1301  USA
> + */
> +#include "xfs.h"
> +#include "xfs_fs.h"
> +#include "xfs_format.h"
> +#include "xfs_log.h"
> +#include "xfs_trans.h"
> +#include "xfs_sb.h"
> +#include "xfs_ag.h"
> +#include "xfs_mount.h"
> +#include "xfs_bmap_btree.h"
> +#include "xfs_ialloc_btree.h"
> +#include "xfs_dinode.h"
> +#include "xfs_inode.h"
> +#include "xfs_error.h"
> +#include "xfs_cksum.h"
> +#include "xfs_icache.h"
> +#include "xfs_ialloc.h"
> +
> +/*
> + * Check that none of the inode's in the buffer have a next
> + * unlinked field of 0.
> + */
> +#if defined(DEBUG)
> +void
> +xfs_inobp_check(
> +	xfs_mount_t	*mp,
> +	xfs_buf_t	*bp)
> +{
> +	int		i;
> +	int		j;
> +	xfs_dinode_t	*dip;
> +
> +	j = mp->m_inode_cluster_size >> mp->m_sb.sb_inodelog;
> +
> +	for (i = 0; i < j; i++) {
> +		dip = (xfs_dinode_t *)xfs_buf_offset(bp,
> +					i * mp->m_sb.sb_inodesize);
> +		if (!dip->di_next_unlinked)  {
> +			xfs_alert(mp,
> +	"Detected bogus zero next_unlinked field in incore inode buffer 0x%p.",
> +				bp);
> +			ASSERT(dip->di_next_unlinked);
> +		}
> +	}
> +}
> +#endif
> +
> +static void
> +xfs_inode_buf_verify(
> +	struct xfs_buf	*bp)
> +{
> +	struct xfs_mount *mp = bp->b_target->bt_mount;
> +	int		i;
> +	int		ni;
> +
> +	/*
> +	 * Validate the magic number and version of every inode in the buffer
> +	 */
> +	ni = XFS_BB_TO_FSB(mp, bp->b_length) * mp->m_sb.sb_inopblock;
> +	for (i = 0; i < ni; i++) {
> +		int		di_ok;
> +		xfs_dinode_t	*dip;
> +
> +		dip = (struct xfs_dinode *)xfs_buf_offset(bp,
> +					(i << mp->m_sb.sb_inodelog));
> +		di_ok = dip->di_magic == cpu_to_be16(XFS_DINODE_MAGIC) &&
> +			    XFS_DINODE_GOOD_VERSION(dip->di_version);
> +		if (unlikely(XFS_TEST_ERROR(!di_ok, mp,
> +						XFS_ERRTAG_ITOBP_INOTOBP,
> +						XFS_RANDOM_ITOBP_INOTOBP))) {
> +			xfs_buf_ioerror(bp, EFSCORRUPTED);
> +			XFS_CORRUPTION_ERROR(__func__, XFS_ERRLEVEL_HIGH,
> +					     mp, dip);
> +#ifdef DEBUG
> +			xfs_emerg(mp,
> +				"bad inode magic/vsn daddr %lld #%d (magic=%x)",
> +				(unsigned long long)bp->b_bn, i,
> +				be16_to_cpu(dip->di_magic));
> +			ASSERT(0);
> +#endif
> +		}
> +	}
> +	xfs_inobp_check(mp, bp);
> +}
> +
> +static void
> +xfs_inode_buf_read_verify(
> +	struct xfs_buf	*bp)
> +{
> +	xfs_inode_buf_verify(bp);
> +}
> +
> +static void
> +xfs_inode_buf_write_verify(
> +	struct xfs_buf	*bp)
> +{
> +	xfs_inode_buf_verify(bp);
> +}
> +
> +const struct xfs_buf_ops xfs_inode_buf_ops = {
> +	.verify_read = xfs_inode_buf_read_verify,
> +	.verify_write = xfs_inode_buf_write_verify,
> +};
> +
> +/*
> + * This routine is called to map an inode to the buffer containing the on-disk
> + * version of the inode.  It returns a pointer to the buffer containing the
> + * on-disk inode in the bpp parameter, and in the dipp parameter it returns a
> + * pointer to the on-disk inode within that buffer.
> + *
> + * If a non-zero error is returned, then the contents of bpp and dipp are
> + * undefined.
> + */
> +int
> +xfs_imap_to_bp(
> +	struct xfs_mount	*mp,
> +	struct xfs_trans	*tp,
> +	struct xfs_imap		*imap,
> +	struct xfs_dinode       **dipp,
> +	struct xfs_buf		**bpp,
> +	uint			buf_flags,
> +	uint			iget_flags)
> +{
> +	struct xfs_buf		*bp;
> +	int			error;
> +
> +	buf_flags |= XBF_UNMAPPED;
> +	error = xfs_trans_read_buf(mp, tp, mp->m_ddev_targp, imap->im_blkno,
> +				   (int)imap->im_len, buf_flags, &bp,
> +				   &xfs_inode_buf_ops);
> +	if (error) {
> +		if (error == EAGAIN) {
> +			ASSERT(buf_flags & XBF_TRYLOCK);
> +			return error;
> +		}
> +
> +		if (error == EFSCORRUPTED &&
> +		    (iget_flags & XFS_IGET_UNTRUSTED))
> +			return XFS_ERROR(EINVAL);
> +
> +		xfs_warn(mp, "%s: xfs_trans_read_buf() returned error %d.",
> +			__func__, error);
> +		return error;
> +	}
> +
> +	*bpp = bp;
> +	*dipp = (struct xfs_dinode *)xfs_buf_offset(bp, imap->im_boffset);
> +	return 0;
> +}
> +
> +STATIC void
> +xfs_dinode_from_disk(
> +	xfs_icdinode_t		*to,
> +	xfs_dinode_t		*from)
> +{
> +	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;
> +	to->di_onlink = be16_to_cpu(from->di_onlink);
> +	to->di_uid = be32_to_cpu(from->di_uid);
> +	to->di_gid = be32_to_cpu(from->di_gid);
> +	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);
> +	to->di_atime.t_sec = be32_to_cpu(from->di_atime.t_sec);
> +	to->di_atime.t_nsec = be32_to_cpu(from->di_atime.t_nsec);
> +	to->di_mtime.t_sec = be32_to_cpu(from->di_mtime.t_sec);
> +	to->di_mtime.t_nsec = be32_to_cpu(from->di_mtime.t_nsec);
> +	to->di_ctime.t_sec = be32_to_cpu(from->di_ctime.t_sec);
> +	to->di_ctime.t_nsec = be32_to_cpu(from->di_ctime.t_nsec);
> +	to->di_size = be64_to_cpu(from->di_size);
> +	to->di_nblocks = be64_to_cpu(from->di_nblocks);
> +	to->di_extsize = be32_to_cpu(from->di_extsize);
> +	to->di_nextents = be32_to_cpu(from->di_nextents);
> +	to->di_anextents = be16_to_cpu(from->di_anextents);
> +	to->di_forkoff = from->di_forkoff;
> +	to->di_aformat	= from->di_aformat;
> +	to->di_dmevmask	= be32_to_cpu(from->di_dmevmask);
> +	to->di_dmstate	= be16_to_cpu(from->di_dmstate);
> +	to->di_flags	= be16_to_cpu(from->di_flags);
> +	to->di_gen	= be32_to_cpu(from->di_gen);
> +
> +	if (to->di_version == 3) {
> +		to->di_changecount = be64_to_cpu(from->di_changecount);
> +		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_dinode_to_disk(
> +	xfs_dinode_t		*to,
> +	xfs_icdinode_t		*from)
> +{
> +	to->di_magic = cpu_to_be16(from->di_magic);
> +	to->di_mode = cpu_to_be16(from->di_mode);
> +	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);
> +	to->di_gid = cpu_to_be32(from->di_gid);
> +	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));
> +	to->di_flushiter = cpu_to_be16(from->di_flushiter);
> +	to->di_atime.t_sec = cpu_to_be32(from->di_atime.t_sec);
> +	to->di_atime.t_nsec = cpu_to_be32(from->di_atime.t_nsec);
> +	to->di_mtime.t_sec = cpu_to_be32(from->di_mtime.t_sec);
> +	to->di_mtime.t_nsec = cpu_to_be32(from->di_mtime.t_nsec);
> +	to->di_ctime.t_sec = cpu_to_be32(from->di_ctime.t_sec);
> +	to->di_ctime.t_nsec = cpu_to_be32(from->di_ctime.t_nsec);
> +	to->di_size = cpu_to_be64(from->di_size);
> +	to->di_nblocks = cpu_to_be64(from->di_nblocks);
> +	to->di_extsize = cpu_to_be32(from->di_extsize);
> +	to->di_nextents = cpu_to_be32(from->di_nextents);
> +	to->di_anextents = cpu_to_be16(from->di_anextents);
> +	to->di_forkoff = from->di_forkoff;
> +	to->di_aformat = from->di_aformat;
> +	to->di_dmevmask = cpu_to_be32(from->di_dmevmask);
> +	to->di_dmstate = cpu_to_be16(from->di_dmstate);
> +	to->di_flags = cpu_to_be16(from->di_flags);
> +	to->di_gen = cpu_to_be32(from->di_gen);
> +
> +	if (from->di_version == 3) {
> +		to->di_changecount = cpu_to_be64(from->di_changecount);
> +		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);
> +	}
> +}
> +
> +static bool
> +xfs_dinode_verify(
> +	struct xfs_mount	*mp,
> +	struct xfs_inode	*ip,
> +	struct xfs_dinode	*dip)
> +{
> +	if (dip->di_magic != cpu_to_be16(XFS_DINODE_MAGIC))
> +		return false;
> +
> +	/* only version 3 or greater inodes are extensively verified here */
> +	if (dip->di_version < 3)
> +		return true;
> +
> +	if (!xfs_sb_version_hascrc(&mp->m_sb))
> +		return false;
> +	if (!xfs_verify_cksum((char *)dip, mp->m_sb.sb_inodesize,
> +			      offsetof(struct xfs_dinode, di_crc)))
> +		return false;
> +	if (be64_to_cpu(dip->di_ino) != ip->i_ino)
> +		return false;
> +	if (!uuid_equal(&dip->di_uuid, &mp->m_sb.sb_uuid))
> +		return false;
> +	return true;
> +}
> +
> +void
> +xfs_dinode_calc_crc(
> +	struct xfs_mount	*mp,
> +	struct xfs_dinode	*dip)
> +{
> +	__uint32_t		crc;
> +
> +	if (dip->di_version < 3)
> +		return;
> +
> +	ASSERT(xfs_sb_version_hascrc(&mp->m_sb));
> +	crc = xfs_start_cksum((char *)dip, mp->m_sb.sb_inodesize,
> +			      offsetof(struct xfs_dinode, di_crc));
> +	dip->di_crc = xfs_end_cksum(crc);
> +}
> +
> +/*
> + * Read the disk inode attributes into the in-core inode structure.
> + *
> + * If we are initialising a new inode and we are not utilising the
> + * XFS_MOUNT_IKEEP inode cluster mode, we can simple build the new inode core
> + * with a random generation number. If we are keeping inodes around, we need to
> + * read the inode cluster to get the existing generation number off disk.
> + */
> +int
> +xfs_iread(
> +	xfs_mount_t	*mp,
> +	xfs_trans_t	*tp,
> +	xfs_inode_t	*ip,
> +	uint		iget_flags)
> +{
> +	xfs_buf_t	*bp;
> +	xfs_dinode_t	*dip;
> +	int		error;
> +
> +	/*
> +	 * Fill in the location information in the in-core inode.
> +	 */
> +	error = xfs_imap(mp, tp, ip->i_ino, &ip->i_imap, iget_flags);
> +	if (error)
> +		return error;
> +
> +	/* shortcut IO on inode allocation if possible */
> +	if ((iget_flags & XFS_IGET_CREATE) &&
> +	    !(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)) {
> +			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_uuid);
> +		} else
> +			ip->i_d.di_version = 2;
> +		return 0;
> +	}
> +
> +	/*
> +	 * Get pointers to the on-disk inode and the buffer containing it.
> +	 */
> +	error = xfs_imap_to_bp(mp, tp, &ip->i_imap, &dip, &bp, 0, iget_flags);
> +	if (error)
> +		return error;
> +
> +	/* even unallocated inodes are verified */
> +	if (!xfs_dinode_verify(mp, ip, dip)) {
> +		xfs_alert(mp, "%s: validation failed for inode %lld failed",
> +				__func__, ip->i_ino);
> +
> +		XFS_CORRUPTION_ERROR(__func__, XFS_ERRLEVEL_LOW, mp, dip);
> +		error = XFS_ERROR(EFSCORRUPTED);
> +		goto out_brelse;
> +	}
> +
> +	/*
> +	 * If the on-disk inode is already linked to a directory
> +	 * entry, copy all of the inode into the in-core inode.
> +	 * xfs_iformat_fork() handles copying in the inode format
> +	 * specific information.
> +	 * Otherwise, just get the truly permanent information.
> +	 */
> +	if (dip->di_mode) {
> +		xfs_dinode_from_disk(&ip->i_d, dip);
> +		error = xfs_iformat_fork(ip, dip);
> +		if (error)  {
> +#ifdef DEBUG
> +			xfs_alert(mp, "%s: xfs_iformat() returned error %d",
> +				__func__, error);
> +#endif /* DEBUG */
> +			goto out_brelse;
> +		}
> +	} else {
> +		/*
> +		 * 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.
> +		 * This ensures that xfs_inactive() will see that
> +		 * the inode is already free and not try to mess
> +		 * with the uninitialized part of it.
> +		 */
> +		ip->i_d.di_mode = 0;
> +	}
> +
> +	/*
> +	 * The inode format changed when we moved the link count and
> +	 * made it 32 bits long.  If this is an old format inode,
> +	 * convert it in memory to look like a new one.  If it gets
> +	 * flushed to disk we will convert back before flushing or
> +	 * logging it.  We zero out the new projid field and the old link
> +	 * count field.  We'll handle clearing the pad field (the remains
> +	 * of the old uuid field) when we actually convert the inode to
> +	 * the new format. We don't change the version number so that we
> +	 * can distinguish this from a real new format inode.
> +	 */
> +	if (ip->i_d.di_version == 1) {
> +		ip->i_d.di_nlink = ip->i_d.di_onlink;
> +		ip->i_d.di_onlink = 0;
> +		xfs_set_projid(ip, 0);
> +	}
> +
> +	ip->i_delayed_blks = 0;
> +
> +	/*
> +	 * Mark the buffer containing the inode as something to keep
> +	 * around for a while.  This helps to keep recently accessed
> +	 * meta-data in-core longer.
> +	 */
> +	xfs_buf_set_ref(bp, XFS_INO_REF);
> +
> +	/*
> +	 * Use xfs_trans_brelse() to release the buffer containing the on-disk
> +	 * inode, because it was acquired with xfs_trans_read_buf() in
> +	 * xfs_imap_to_bp() above.  If tp is NULL, this is just a normal
> +	 * brelse().  If we're within a transaction, then xfs_trans_brelse()
> +	 * will only release the buffer if it is not dirty within the
> +	 * transaction.  It will be OK to release the buffer in this case,
> +	 * because inodes on disk are never destroyed and we will be locking the
> +	 * new in-core inode before putting it in the cache where other
> +	 * processes can find it.  Thus we don't have to worry about the inode
> +	 * being changed just because we released the buffer.
> +	 */
> + out_brelse:
> +	xfs_trans_brelse(tp, bp);
> +	return error;
> +}
> diff --git a/fs/xfs/xfs_inode_buf.h b/fs/xfs/xfs_inode_buf.h
> new file mode 100644
> index 0000000..b5f1e22
> --- /dev/null
> +++ b/fs/xfs/xfs_inode_buf.h
> @@ -0,0 +1,53 @@
> +/*
> + * Copyright (c) 2000-2003,2005 Silicon Graphics, Inc.
> + * All Rights Reserved.
> + *
> + * This program is free software; you can redistribute it and/or
> + * modify it under the terms of the GNU General Public License as
> + * published by the Free Software Foundation.
> + *
> + * This program is distributed in the hope that it would be useful,
> + * but WITHOUT ANY WARRANTY; without even the implied warranty of
> + * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
> + * GNU General Public License for more details.
> + *
> + * You should have received a copy of the GNU General Public License
> + * along with this program; if not, write the Free Software Foundation,
> + * Inc.,  51 Franklin St, Fifth Floor, Boston, MA  02110-1301  USA
> + */
> +#ifndef	__XFS_INODE_BUF_H__
> +#define	__XFS_INODE_BUF_H__
> +
> +struct xfs_inode;
> +struct xfs_dinode;
> +struct xfs_icdinode;
> +
> +/*
> + * Inode location information.  Stored in the inode and passed to
> + * xfs_imap_to_bp() to get a buffer and dinode for a given inode.
> + */
> +struct xfs_imap {
> +	xfs_daddr_t	im_blkno;	/* starting BB of inode chunk */
> +	ushort		im_len;		/* length in BBs of inode chunk */
> +	ushort		im_boffset;	/* inode offset in block in bytes */
> +};
> +
> +int		xfs_imap_to_bp(struct xfs_mount *, struct xfs_trans *,
> +			       struct xfs_imap *, struct xfs_dinode **,
> +			       struct xfs_buf **, uint, uint);
> +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_dinode_to_disk(struct xfs_dinode *,
> +				   struct xfs_icdinode *);
> +bool		xfs_can_free_eofblocks(struct xfs_inode *, bool);
> +
> +#if defined(DEBUG)
> +void		xfs_inobp_check(struct xfs_mount *, struct xfs_buf *);
> +#else
> +#define	xfs_inobp_check(mp, bp)
> +#endif /* DEBUG */
> +
> +extern const struct xfs_buf_ops xfs_inode_buf_ops;
> +
> +#endif	/* __XFS_INODE_BUF_H__ */
> 

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