On Tue, Oct 17, 2023 at 07:10:31PM -0700, Darrick J. Wong wrote:
> From: Darrick J. Wong <djwong@xxxxxxxxxx>
>
> Create get and set functions for rtbitmap words so that we can redefine
> the ondisk format with a specific endianness. Note that this requires
> the definition of a distinct type for ondisk rtbitmap words so that the
> compiler can perform proper typechecking as we go back and forth.
>
> In the upcoming rtgroups feature, we're going to fix the problem that
> rtwords are written in host endian order, which means we'll need the
> distinct rtword/rtword_raw types.
>
Oh, I should add:
Suggested-by: Christoph Hellwig <hch@xxxxxx>
--D
> Signed-off-by: Darrick J. Wong <djwong@xxxxxxxxxx>
> ---
> fs/xfs/libxfs/xfs_format.h | 8 +++
> fs/xfs/libxfs/xfs_rtbitmap.c | 109 +++++++++++++-----------------------------
> fs/xfs/libxfs/xfs_rtbitmap.h | 27 ++++++++++
> fs/xfs/xfs_ondisk.h | 3 +
> 4 files changed, 70 insertions(+), 77 deletions(-)
>
>
> diff --git a/fs/xfs/libxfs/xfs_format.h b/fs/xfs/libxfs/xfs_format.h
> index d48e3a395bd9..2af891d5d171 100644
> --- a/fs/xfs/libxfs/xfs_format.h
> +++ b/fs/xfs/libxfs/xfs_format.h
> @@ -690,6 +690,14 @@ struct xfs_agfl {
> ASSERT(xfs_daddr_to_agno(mp, d) == \
> xfs_daddr_to_agno(mp, (d) + (len) - 1)))
>
> +/*
> + * Realtime bitmap information is accessed by the word, which is currently
> + * stored in host-endian format.
> + */
> +union xfs_rtword_raw {
> + __u32 old;
> +};
> +
> /*
> * XFS Timestamps
> * ==============
> diff --git a/fs/xfs/libxfs/xfs_rtbitmap.c b/fs/xfs/libxfs/xfs_rtbitmap.c
> index d05bd0218885..0e83eca507dd 100644
> --- a/fs/xfs/libxfs/xfs_rtbitmap.c
> +++ b/fs/xfs/libxfs/xfs_rtbitmap.c
> @@ -99,7 +99,6 @@ xfs_rtfind_back(
> xfs_rtxnum_t limit, /* last rtext to look at */
> xfs_rtxnum_t *rtx) /* out: start rtext found */
> {
> - xfs_rtword_t *b; /* current word in buffer */
> int bit; /* bit number in the word */
> xfs_fileoff_t block; /* bitmap block number */
> struct xfs_buf *bp; /* buf for the block */
> @@ -110,6 +109,7 @@ xfs_rtfind_back(
> xfs_rtword_t mask; /* mask of relevant bits for value */
> xfs_rtword_t want; /* mask for "good" values */
> xfs_rtword_t wdiff; /* difference from wanted value */
> + xfs_rtword_t incore;
> unsigned int word; /* word number in the buffer */
>
> /*
> @@ -125,14 +125,14 @@ xfs_rtfind_back(
> * Get the first word's index & point to it.
> */
> word = xfs_rtx_to_rbmword(mp, start);
> - b = xfs_rbmblock_wordptr(bp, word);
> bit = (int)(start & (XFS_NBWORD - 1));
> len = start - limit + 1;
> /*
> * Compute match value, based on the bit at start: if 1 (free)
> * then all-ones, else all-zeroes.
> */
> - want = (*b & ((xfs_rtword_t)1 << bit)) ? -1 : 0;
> + incore = xfs_rtbitmap_getword(bp, word);
> + want = (incore & ((xfs_rtword_t)1 << bit)) ? -1 : 0;
> /*
> * If the starting position is not word-aligned, deal with the
> * partial word.
> @@ -149,7 +149,7 @@ xfs_rtfind_back(
> * Calculate the difference between the value there
> * and what we're looking for.
> */
> - if ((wdiff = (*b ^ want) & mask)) {
> + if ((wdiff = (incore ^ want) & mask)) {
> /*
> * Different. Mark where we are and return.
> */
> @@ -174,12 +174,6 @@ xfs_rtfind_back(
> }
>
> word = mp->m_blockwsize - 1;
> - b = xfs_rbmblock_wordptr(bp, word);
> - } else {
> - /*
> - * Go on to the previous word in the buffer.
> - */
> - b--;
> }
> } else {
> /*
> @@ -195,7 +189,8 @@ xfs_rtfind_back(
> /*
> * Compute difference between actual and desired value.
> */
> - if ((wdiff = *b ^ want)) {
> + incore = xfs_rtbitmap_getword(bp, word);
> + if ((wdiff = incore ^ want)) {
> /*
> * Different, mark where we are and return.
> */
> @@ -220,12 +215,6 @@ xfs_rtfind_back(
> }
>
> word = mp->m_blockwsize - 1;
> - b = xfs_rbmblock_wordptr(bp, word);
> - } else {
> - /*
> - * Go on to the previous word in the buffer.
> - */
> - b--;
> }
> }
> /*
> @@ -242,7 +231,8 @@ xfs_rtfind_back(
> /*
> * Compute difference between actual and desired value.
> */
> - if ((wdiff = (*b ^ want) & mask)) {
> + incore = xfs_rtbitmap_getword(bp, word);
> + if ((wdiff = (incore ^ want) & mask)) {
> /*
> * Different, mark where we are and return.
> */
> @@ -273,7 +263,6 @@ xfs_rtfind_forw(
> xfs_rtxnum_t limit, /* last rtext to look at */
> xfs_rtxnum_t *rtx) /* out: start rtext found */
> {
> - xfs_rtword_t *b; /* current word in buffer */
> int bit; /* bit number in the word */
> xfs_fileoff_t block; /* bitmap block number */
> struct xfs_buf *bp; /* buf for the block */
> @@ -284,6 +273,7 @@ xfs_rtfind_forw(
> xfs_rtword_t mask; /* mask of relevant bits for value */
> xfs_rtword_t want; /* mask for "good" values */
> xfs_rtword_t wdiff; /* difference from wanted value */
> + xfs_rtword_t incore;
> unsigned int word; /* word number in the buffer */
>
> /*
> @@ -299,14 +289,14 @@ xfs_rtfind_forw(
> * Get the first word's index & point to it.
> */
> word = xfs_rtx_to_rbmword(mp, start);
> - b = xfs_rbmblock_wordptr(bp, word);
> bit = (int)(start & (XFS_NBWORD - 1));
> len = limit - start + 1;
> /*
> * Compute match value, based on the bit at start: if 1 (free)
> * then all-ones, else all-zeroes.
> */
> - want = (*b & ((xfs_rtword_t)1 << bit)) ? -1 : 0;
> + incore = xfs_rtbitmap_getword(bp, word);
> + want = (incore & ((xfs_rtword_t)1 << bit)) ? -1 : 0;
> /*
> * If the starting position is not word-aligned, deal with the
> * partial word.
> @@ -322,7 +312,7 @@ xfs_rtfind_forw(
> * Calculate the difference between the value there
> * and what we're looking for.
> */
> - if ((wdiff = (*b ^ want) & mask)) {
> + if ((wdiff = (incore ^ want) & mask)) {
> /*
> * Different. Mark where we are and return.
> */
> @@ -347,12 +337,6 @@ xfs_rtfind_forw(
> }
>
> word = 0;
> - b = xfs_rbmblock_wordptr(bp, word);
> - } else {
> - /*
> - * Go on to the previous word in the buffer.
> - */
> - b++;
> }
> } else {
> /*
> @@ -368,7 +352,8 @@ xfs_rtfind_forw(
> /*
> * Compute difference between actual and desired value.
> */
> - if ((wdiff = *b ^ want)) {
> + incore = xfs_rtbitmap_getword(bp, word);
> + if ((wdiff = incore ^ want)) {
> /*
> * Different, mark where we are and return.
> */
> @@ -393,12 +378,6 @@ xfs_rtfind_forw(
> }
>
> word = 0;
> - b = xfs_rbmblock_wordptr(bp, word);
> - } else {
> - /*
> - * Go on to the next word in the buffer.
> - */
> - b++;
> }
> }
> /*
> @@ -413,7 +392,8 @@ xfs_rtfind_forw(
> /*
> * Compute difference between actual and desired value.
> */
> - if ((wdiff = (*b ^ want) & mask)) {
> + incore = xfs_rtbitmap_getword(bp, word);
> + if ((wdiff = (incore ^ want) & mask)) {
> /*
> * Different, mark where we are and return.
> */
> @@ -562,15 +542,14 @@ xfs_rtmodify_range(
> xfs_rtxlen_t len, /* length of extent to modify */
> int val) /* 1 for free, 0 for allocated */
> {
> - xfs_rtword_t *b; /* current word in buffer */
> int bit; /* bit number in the word */
> xfs_fileoff_t block; /* bitmap block number */
> struct xfs_buf *bp; /* buf for the block */
> int error; /* error value */
> - xfs_rtword_t *first; /* first used word in the buffer */
> int i; /* current bit number rel. to start */
> int lastbit; /* last useful bit in word */
> xfs_rtword_t mask; /* mask o frelevant bits for value */
> + xfs_rtword_t incore;
> unsigned int firstword; /* first word used in the buffer */
> unsigned int word; /* word number in the buffer */
>
> @@ -590,7 +569,6 @@ xfs_rtmodify_range(
> * Compute the starting word's address, and starting bit.
> */
> firstword = word = xfs_rtx_to_rbmword(mp, start);
> - first = b = xfs_rbmblock_wordptr(bp, word);
> bit = (int)(start & (XFS_NBWORD - 1));
> /*
> * 0 (allocated) => all zeroes; 1 (free) => all ones.
> @@ -609,10 +587,12 @@ xfs_rtmodify_range(
> /*
> * Set/clear the active bits.
> */
> + incore = xfs_rtbitmap_getword(bp, word);
> if (val)
> - *b |= mask;
> + incore |= mask;
> else
> - *b &= ~mask;
> + incore &= ~mask;
> + xfs_rtbitmap_setword(bp, word, incore);
> i = lastbit - bit;
> /*
> * Go on to the next block if that's where the next word is
> @@ -630,12 +610,6 @@ xfs_rtmodify_range(
> }
>
> firstword = word = 0;
> - first = b = xfs_rbmblock_wordptr(bp, word);
> - } else {
> - /*
> - * Go on to the next word in the buffer
> - */
> - b++;
> }
> } else {
> /*
> @@ -651,7 +625,7 @@ xfs_rtmodify_range(
> /*
> * Set the word value correctly.
> */
> - *b = val;
> + xfs_rtbitmap_setword(bp, word, val);
> i += XFS_NBWORD;
> /*
> * Go on to the next block if that's where the next word is
> @@ -669,12 +643,6 @@ xfs_rtmodify_range(
> }
>
> firstword = word = 0;
> - first = b = xfs_rbmblock_wordptr(bp, word);
> - } else {
> - /*
> - * Go on to the next word in the buffer
> - */
> - b++;
> }
> }
> /*
> @@ -689,17 +657,18 @@ xfs_rtmodify_range(
> /*
> * Set/clear the active bits.
> */
> + incore = xfs_rtbitmap_getword(bp, word);
> if (val)
> - *b |= mask;
> + incore |= mask;
> else
> - *b &= ~mask;
> + incore &= ~mask;
> + xfs_rtbitmap_setword(bp, word, incore);
> word++;
> - b++;
> }
> /*
> * Log any remaining changed bytes.
> */
> - if (b > first)
> + if (word > firstword)
> xfs_trans_log_rtbitmap(tp, bp, firstword, word);
> return 0;
> }
> @@ -794,7 +763,6 @@ xfs_rtcheck_range(
> xfs_rtxnum_t *new, /* out: first rtext not matching */
> int *stat) /* out: 1 for matches, 0 for not */
> {
> - xfs_rtword_t *b; /* current word in buffer */
> int bit; /* bit number in the word */
> xfs_fileoff_t block; /* bitmap block number */
> struct xfs_buf *bp; /* buf for the block */
> @@ -803,6 +771,7 @@ xfs_rtcheck_range(
> xfs_rtxnum_t lastbit; /* last useful bit in word */
> xfs_rtword_t mask; /* mask of relevant bits for value */
> xfs_rtword_t wdiff; /* difference from wanted value */
> + xfs_rtword_t incore;
> unsigned int word; /* word number in the buffer */
>
> /*
> @@ -821,7 +790,6 @@ xfs_rtcheck_range(
> * Compute the starting word's address, and starting bit.
> */
> word = xfs_rtx_to_rbmword(mp, start);
> - b = xfs_rbmblock_wordptr(bp, word);
> bit = (int)(start & (XFS_NBWORD - 1));
> /*
> * 0 (allocated) => all zero's; 1 (free) => all one's.
> @@ -843,7 +811,8 @@ xfs_rtcheck_range(
> /*
> * Compute difference between actual and desired value.
> */
> - if ((wdiff = (*b ^ val) & mask)) {
> + incore = xfs_rtbitmap_getword(bp, word);
> + if ((wdiff = (incore ^ val) & mask)) {
> /*
> * Different, compute first wrong bit and return.
> */
> @@ -869,12 +838,6 @@ xfs_rtcheck_range(
> }
>
> word = 0;
> - b = xfs_rbmblock_wordptr(bp, word);
> - } else {
> - /*
> - * Go on to the next word in the buffer.
> - */
> - b++;
> }
> } else {
> /*
> @@ -890,7 +853,8 @@ xfs_rtcheck_range(
> /*
> * Compute difference between actual and desired value.
> */
> - if ((wdiff = *b ^ val)) {
> + incore = xfs_rtbitmap_getword(bp, word);
> + if ((wdiff = incore ^ val)) {
> /*
> * Different, compute first wrong bit and return.
> */
> @@ -916,12 +880,6 @@ xfs_rtcheck_range(
> }
>
> word = 0;
> - b = xfs_rbmblock_wordptr(bp, word);
> - } else {
> - /*
> - * Go on to the next word in the buffer.
> - */
> - b++;
> }
> }
> /*
> @@ -936,7 +894,8 @@ xfs_rtcheck_range(
> /*
> * Compute difference between actual and desired value.
> */
> - if ((wdiff = (*b ^ val) & mask)) {
> + incore = xfs_rtbitmap_getword(bp, word);
> + if ((wdiff = (incore ^ val) & mask)) {
> /*
> * Different, compute first wrong bit and return.
> */
> diff --git a/fs/xfs/libxfs/xfs_rtbitmap.h b/fs/xfs/libxfs/xfs_rtbitmap.h
> index 01eabb9b5516..ede24de74620 100644
> --- a/fs/xfs/libxfs/xfs_rtbitmap.h
> +++ b/fs/xfs/libxfs/xfs_rtbitmap.h
> @@ -159,16 +159,39 @@ xfs_rbmblock_to_rtx(
> }
>
> /* Return a pointer to a bitmap word within a rt bitmap block. */
> -static inline xfs_rtword_t *
> +static inline union xfs_rtword_raw *
> xfs_rbmblock_wordptr(
> struct xfs_buf *bp,
> unsigned int index)
> {
> - xfs_rtword_t *words = bp->b_addr;
> + union xfs_rtword_raw *words = bp->b_addr;
>
> return words + index;
> }
>
> +/* Convert an ondisk bitmap word to its incore representation. */
> +static inline xfs_rtword_t
> +xfs_rtbitmap_getword(
> + struct xfs_buf *bp,
> + unsigned int index)
> +{
> + union xfs_rtword_raw *word = xfs_rbmblock_wordptr(bp, index);
> +
> + return word->old;
> +}
> +
> +/* Set an ondisk bitmap word from an incore representation. */
> +static inline void
> +xfs_rtbitmap_setword(
> + struct xfs_buf *bp,
> + unsigned int index,
> + xfs_rtword_t value)
> +{
> + union xfs_rtword_raw *word = xfs_rbmblock_wordptr(bp, index);
> +
> + word->old = value;
> +}
> +
> /*
> * Convert a rt extent length and rt bitmap block number to a xfs_suminfo_t
> * offset within the rt summary file.
> diff --git a/fs/xfs/xfs_ondisk.h b/fs/xfs/xfs_ondisk.h
> index c4cc99b70dd3..14d455f768d3 100644
> --- a/fs/xfs/xfs_ondisk.h
> +++ b/fs/xfs/xfs_ondisk.h
> @@ -72,6 +72,9 @@ xfs_check_ondisk_structs(void)
> XFS_CHECK_STRUCT_SIZE(xfs_attr_leaf_map_t, 4);
> XFS_CHECK_STRUCT_SIZE(xfs_attr_leaf_name_local_t, 4);
>
> + /* realtime structures */
> + XFS_CHECK_STRUCT_SIZE(union xfs_rtword_raw, 4);
> +
> /*
> * m68k has problems with xfs_attr_leaf_name_remote_t, but we pad it to
> * 4 bytes anyway so it's not obviously a problem. Hence for the moment
>
