diff options
Diffstat (limited to 'kernel/fs/xfs/libxfs/xfs_rtbitmap.c')
| -rw-r--r-- | kernel/fs/xfs/libxfs/xfs_rtbitmap.c | 991 |
1 files changed, 991 insertions, 0 deletions
diff --git a/kernel/fs/xfs/libxfs/xfs_rtbitmap.c b/kernel/fs/xfs/libxfs/xfs_rtbitmap.c new file mode 100644 index 000000000..9b59ffa1f --- /dev/null +++ b/kernel/fs/xfs/libxfs/xfs_rtbitmap.c @@ -0,0 +1,991 @@ +/* + * Copyright (c) 2000-2005 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 + */ +#include "xfs.h" +#include "xfs_fs.h" +#include "xfs_shared.h" +#include "xfs_format.h" +#include "xfs_log_format.h" +#include "xfs_trans_resv.h" +#include "xfs_bit.h" +#include "xfs_mount.h" +#include "xfs_inode.h" +#include "xfs_bmap.h" +#include "xfs_bmap_util.h" +#include "xfs_bmap_btree.h" +#include "xfs_alloc.h" +#include "xfs_error.h" +#include "xfs_trans.h" +#include "xfs_trans_space.h" +#include "xfs_trace.h" +#include "xfs_buf.h" +#include "xfs_icache.h" +#include "xfs_rtalloc.h" + + +/* + * Realtime allocator bitmap functions shared with userspace. + */ + +/* + * Get a buffer for the bitmap or summary file block specified. + * The buffer is returned read and locked. + */ +int +xfs_rtbuf_get( + xfs_mount_t *mp, /* file system mount structure */ + xfs_trans_t *tp, /* transaction pointer */ + xfs_rtblock_t block, /* block number in bitmap or summary */ + int issum, /* is summary not bitmap */ + xfs_buf_t **bpp) /* output: buffer for the block */ +{ + xfs_buf_t *bp; /* block buffer, result */ + xfs_inode_t *ip; /* bitmap or summary inode */ + xfs_bmbt_irec_t map; + int nmap = 1; + int error; /* error value */ + + ip = issum ? mp->m_rsumip : mp->m_rbmip; + + error = xfs_bmapi_read(ip, block, 1, &map, &nmap, XFS_DATA_FORK); + if (error) + return error; + + ASSERT(map.br_startblock != NULLFSBLOCK); + error = xfs_trans_read_buf(mp, tp, mp->m_ddev_targp, + XFS_FSB_TO_DADDR(mp, map.br_startblock), + mp->m_bsize, 0, &bp, NULL); + if (error) + return error; + *bpp = bp; + return 0; +} + +/* + * Searching backward from start to limit, find the first block whose + * allocated/free state is different from start's. + */ +int +xfs_rtfind_back( + xfs_mount_t *mp, /* file system mount point */ + xfs_trans_t *tp, /* transaction pointer */ + xfs_rtblock_t start, /* starting block to look at */ + xfs_rtblock_t limit, /* last block to look at */ + xfs_rtblock_t *rtblock) /* out: start block found */ +{ + xfs_rtword_t *b; /* current word in buffer */ + int bit; /* bit number in the word */ + xfs_rtblock_t block; /* bitmap block number */ + xfs_buf_t *bp; /* buf for the block */ + xfs_rtword_t *bufp; /* starting word in buffer */ + int error; /* error value */ + xfs_rtblock_t firstbit; /* first useful bit in the word */ + xfs_rtblock_t i; /* current bit number rel. to start */ + xfs_rtblock_t len; /* length of inspected area */ + 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 */ + int word; /* word number in the buffer */ + + /* + * Compute and read in starting bitmap block for starting block. + */ + block = XFS_BITTOBLOCK(mp, start); + error = xfs_rtbuf_get(mp, tp, block, 0, &bp); + if (error) { + return error; + } + bufp = bp->b_addr; + /* + * Get the first word's index & point to it. + */ + word = XFS_BITTOWORD(mp, start); + b = &bufp[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; + /* + * If the starting position is not word-aligned, deal with the + * partial word. + */ + if (bit < XFS_NBWORD - 1) { + /* + * Calculate first (leftmost) bit number to look at, + * and mask for all the relevant bits in this word. + */ + firstbit = XFS_RTMAX((xfs_srtblock_t)(bit - len + 1), 0); + mask = (((xfs_rtword_t)1 << (bit - firstbit + 1)) - 1) << + firstbit; + /* + * Calculate the difference between the value there + * and what we're looking for. + */ + if ((wdiff = (*b ^ want) & mask)) { + /* + * Different. Mark where we are and return. + */ + xfs_trans_brelse(tp, bp); + i = bit - XFS_RTHIBIT(wdiff); + *rtblock = start - i + 1; + return 0; + } + i = bit - firstbit + 1; + /* + * Go on to previous block if that's where the previous word is + * and we need the previous word. + */ + if (--word == -1 && i < len) { + /* + * If done with this block, get the previous one. + */ + xfs_trans_brelse(tp, bp); + error = xfs_rtbuf_get(mp, tp, --block, 0, &bp); + if (error) { + return error; + } + bufp = bp->b_addr; + word = XFS_BLOCKWMASK(mp); + b = &bufp[word]; + } else { + /* + * Go on to the previous word in the buffer. + */ + b--; + } + } else { + /* + * Starting on a word boundary, no partial word. + */ + i = 0; + } + /* + * Loop over whole words in buffers. When we use up one buffer + * we move on to the previous one. + */ + while (len - i >= XFS_NBWORD) { + /* + * Compute difference between actual and desired value. + */ + if ((wdiff = *b ^ want)) { + /* + * Different, mark where we are and return. + */ + xfs_trans_brelse(tp, bp); + i += XFS_NBWORD - 1 - XFS_RTHIBIT(wdiff); + *rtblock = start - i + 1; + return 0; + } + i += XFS_NBWORD; + /* + * Go on to previous block if that's where the previous word is + * and we need the previous word. + */ + if (--word == -1 && i < len) { + /* + * If done with this block, get the previous one. + */ + xfs_trans_brelse(tp, bp); + error = xfs_rtbuf_get(mp, tp, --block, 0, &bp); + if (error) { + return error; + } + bufp = bp->b_addr; + word = XFS_BLOCKWMASK(mp); + b = &bufp[word]; + } else { + /* + * Go on to the previous word in the buffer. + */ + b--; + } + } + /* + * If not ending on a word boundary, deal with the last + * (partial) word. + */ + if (len - i) { + /* + * Calculate first (leftmost) bit number to look at, + * and mask for all the relevant bits in this word. + */ + firstbit = XFS_NBWORD - (len - i); + mask = (((xfs_rtword_t)1 << (len - i)) - 1) << firstbit; + /* + * Compute difference between actual and desired value. + */ + if ((wdiff = (*b ^ want) & mask)) { + /* + * Different, mark where we are and return. + */ + xfs_trans_brelse(tp, bp); + i += XFS_NBWORD - 1 - XFS_RTHIBIT(wdiff); + *rtblock = start - i + 1; + return 0; + } else + i = len; + } + /* + * No match, return that we scanned the whole area. + */ + xfs_trans_brelse(tp, bp); + *rtblock = start - i + 1; + return 0; +} + +/* + * Searching forward from start to limit, find the first block whose + * allocated/free state is different from start's. + */ +int +xfs_rtfind_forw( + xfs_mount_t *mp, /* file system mount point */ + xfs_trans_t *tp, /* transaction pointer */ + xfs_rtblock_t start, /* starting block to look at */ + xfs_rtblock_t limit, /* last block to look at */ + xfs_rtblock_t *rtblock) /* out: start block found */ +{ + xfs_rtword_t *b; /* current word in buffer */ + int bit; /* bit number in the word */ + xfs_rtblock_t block; /* bitmap block number */ + xfs_buf_t *bp; /* buf for the block */ + xfs_rtword_t *bufp; /* starting word in buffer */ + int error; /* error value */ + xfs_rtblock_t i; /* current bit number rel. to start */ + xfs_rtblock_t lastbit; /* last useful bit in the word */ + xfs_rtblock_t len; /* length of inspected area */ + 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 */ + int word; /* word number in the buffer */ + + /* + * Compute and read in starting bitmap block for starting block. + */ + block = XFS_BITTOBLOCK(mp, start); + error = xfs_rtbuf_get(mp, tp, block, 0, &bp); + if (error) { + return error; + } + bufp = bp->b_addr; + /* + * Get the first word's index & point to it. + */ + word = XFS_BITTOWORD(mp, start); + b = &bufp[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; + /* + * If the starting position is not word-aligned, deal with the + * partial word. + */ + if (bit) { + /* + * Calculate last (rightmost) bit number to look at, + * and mask for all the relevant bits in this word. + */ + lastbit = XFS_RTMIN(bit + len, XFS_NBWORD); + mask = (((xfs_rtword_t)1 << (lastbit - bit)) - 1) << bit; + /* + * Calculate the difference between the value there + * and what we're looking for. + */ + if ((wdiff = (*b ^ want) & mask)) { + /* + * Different. Mark where we are and return. + */ + xfs_trans_brelse(tp, bp); + i = XFS_RTLOBIT(wdiff) - bit; + *rtblock = start + i - 1; + return 0; + } + i = lastbit - bit; + /* + * Go on to next block if that's where the next word is + * and we need the next word. + */ + if (++word == XFS_BLOCKWSIZE(mp) && i < len) { + /* + * If done with this block, get the previous one. + */ + xfs_trans_brelse(tp, bp); + error = xfs_rtbuf_get(mp, tp, ++block, 0, &bp); + if (error) { + return error; + } + b = bufp = bp->b_addr; + word = 0; + } else { + /* + * Go on to the previous word in the buffer. + */ + b++; + } + } else { + /* + * Starting on a word boundary, no partial word. + */ + i = 0; + } + /* + * Loop over whole words in buffers. When we use up one buffer + * we move on to the next one. + */ + while (len - i >= XFS_NBWORD) { + /* + * Compute difference between actual and desired value. + */ + if ((wdiff = *b ^ want)) { + /* + * Different, mark where we are and return. + */ + xfs_trans_brelse(tp, bp); + i += XFS_RTLOBIT(wdiff); + *rtblock = start + i - 1; + return 0; + } + i += XFS_NBWORD; + /* + * Go on to next block if that's where the next word is + * and we need the next word. + */ + if (++word == XFS_BLOCKWSIZE(mp) && i < len) { + /* + * If done with this block, get the next one. + */ + xfs_trans_brelse(tp, bp); + error = xfs_rtbuf_get(mp, tp, ++block, 0, &bp); + if (error) { + return error; + } + b = bufp = bp->b_addr; + word = 0; + } else { + /* + * Go on to the next word in the buffer. + */ + b++; + } + } + /* + * If not ending on a word boundary, deal with the last + * (partial) word. + */ + if ((lastbit = len - i)) { + /* + * Calculate mask for all the relevant bits in this word. + */ + mask = ((xfs_rtword_t)1 << lastbit) - 1; + /* + * Compute difference between actual and desired value. + */ + if ((wdiff = (*b ^ want) & mask)) { + /* + * Different, mark where we are and return. + */ + xfs_trans_brelse(tp, bp); + i += XFS_RTLOBIT(wdiff); + *rtblock = start + i - 1; + return 0; + } else + i = len; + } + /* + * No match, return that we scanned the whole area. + */ + xfs_trans_brelse(tp, bp); + *rtblock = start + i - 1; + return 0; +} + +/* + * Read and/or modify the summary information for a given extent size, + * bitmap block combination. + * Keeps track of a current summary block, so we don't keep reading + * it from the buffer cache. + * + * Summary information is returned in *sum if specified. + * If no delta is specified, returns summary only. + */ +int +xfs_rtmodify_summary_int( + xfs_mount_t *mp, /* file system mount structure */ + xfs_trans_t *tp, /* transaction pointer */ + int log, /* log2 of extent size */ + xfs_rtblock_t bbno, /* bitmap block number */ + int delta, /* change to make to summary info */ + xfs_buf_t **rbpp, /* in/out: summary block buffer */ + xfs_fsblock_t *rsb, /* in/out: summary block number */ + xfs_suminfo_t *sum) /* out: summary info for this block */ +{ + xfs_buf_t *bp; /* buffer for the summary block */ + int error; /* error value */ + xfs_fsblock_t sb; /* summary fsblock */ + int so; /* index into the summary file */ + xfs_suminfo_t *sp; /* pointer to returned data */ + + /* + * Compute entry number in the summary file. + */ + so = XFS_SUMOFFS(mp, log, bbno); + /* + * Compute the block number in the summary file. + */ + sb = XFS_SUMOFFSTOBLOCK(mp, so); + /* + * If we have an old buffer, and the block number matches, use that. + */ + if (*rbpp && *rsb == sb) + bp = *rbpp; + /* + * Otherwise we have to get the buffer. + */ + else { + /* + * If there was an old one, get rid of it first. + */ + if (*rbpp) + xfs_trans_brelse(tp, *rbpp); + error = xfs_rtbuf_get(mp, tp, sb, 1, &bp); + if (error) { + return error; + } + /* + * Remember this buffer and block for the next call. + */ + *rbpp = bp; + *rsb = sb; + } + /* + * Point to the summary information, modify/log it, and/or copy it out. + */ + sp = XFS_SUMPTR(mp, bp, so); + if (delta) { + uint first = (uint)((char *)sp - (char *)bp->b_addr); + + *sp += delta; + xfs_trans_log_buf(tp, bp, first, first + sizeof(*sp) - 1); + } + if (sum) + *sum = *sp; + return 0; +} + +int +xfs_rtmodify_summary( + xfs_mount_t *mp, /* file system mount structure */ + xfs_trans_t *tp, /* transaction pointer */ + int log, /* log2 of extent size */ + xfs_rtblock_t bbno, /* bitmap block number */ + int delta, /* change to make to summary info */ + xfs_buf_t **rbpp, /* in/out: summary block buffer */ + xfs_fsblock_t *rsb) /* in/out: summary block number */ +{ + return xfs_rtmodify_summary_int(mp, tp, log, bbno, + delta, rbpp, rsb, NULL); +} + +/* + * Set the given range of bitmap bits to the given value. + * Do whatever I/O and logging is required. + */ +int +xfs_rtmodify_range( + xfs_mount_t *mp, /* file system mount point */ + xfs_trans_t *tp, /* transaction pointer */ + xfs_rtblock_t start, /* starting block to modify */ + xfs_extlen_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_rtblock_t block; /* bitmap block number */ + xfs_buf_t *bp; /* buf for the block */ + xfs_rtword_t *bufp; /* starting word in buffer */ + 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 */ + int word; /* word number in the buffer */ + + /* + * Compute starting bitmap block number. + */ + block = XFS_BITTOBLOCK(mp, start); + /* + * Read the bitmap block, and point to its data. + */ + error = xfs_rtbuf_get(mp, tp, block, 0, &bp); + if (error) { + return error; + } + bufp = bp->b_addr; + /* + * Compute the starting word's address, and starting bit. + */ + word = XFS_BITTOWORD(mp, start); + first = b = &bufp[word]; + bit = (int)(start & (XFS_NBWORD - 1)); + /* + * 0 (allocated) => all zeroes; 1 (free) => all ones. + */ + val = -val; + /* + * If not starting on a word boundary, deal with the first + * (partial) word. + */ + if (bit) { + /* + * Compute first bit not changed and mask of relevant bits. + */ + lastbit = XFS_RTMIN(bit + len, XFS_NBWORD); + mask = (((xfs_rtword_t)1 << (lastbit - bit)) - 1) << bit; + /* + * Set/clear the active bits. + */ + if (val) + *b |= mask; + else + *b &= ~mask; + i = lastbit - bit; + /* + * Go on to the next block if that's where the next word is + * and we need the next word. + */ + if (++word == XFS_BLOCKWSIZE(mp) && i < len) { + /* + * Log the changed part of this block. + * Get the next one. + */ + xfs_trans_log_buf(tp, bp, + (uint)((char *)first - (char *)bufp), + (uint)((char *)b - (char *)bufp)); + error = xfs_rtbuf_get(mp, tp, ++block, 0, &bp); + if (error) { + return error; + } + first = b = bufp = bp->b_addr; + word = 0; + } else { + /* + * Go on to the next word in the buffer + */ + b++; + } + } else { + /* + * Starting on a word boundary, no partial word. + */ + i = 0; + } + /* + * Loop over whole words in buffers. When we use up one buffer + * we move on to the next one. + */ + while (len - i >= XFS_NBWORD) { + /* + * Set the word value correctly. + */ + *b = val; + i += XFS_NBWORD; + /* + * Go on to the next block if that's where the next word is + * and we need the next word. + */ + if (++word == XFS_BLOCKWSIZE(mp) && i < len) { + /* + * Log the changed part of this block. + * Get the next one. + */ + xfs_trans_log_buf(tp, bp, + (uint)((char *)first - (char *)bufp), + (uint)((char *)b - (char *)bufp)); + error = xfs_rtbuf_get(mp, tp, ++block, 0, &bp); + if (error) { + return error; + } + first = b = bufp = bp->b_addr; + word = 0; + } else { + /* + * Go on to the next word in the buffer + */ + b++; + } + } + /* + * If not ending on a word boundary, deal with the last + * (partial) word. + */ + if ((lastbit = len - i)) { + /* + * Compute a mask of relevant bits. + */ + bit = 0; + mask = ((xfs_rtword_t)1 << lastbit) - 1; + /* + * Set/clear the active bits. + */ + if (val) + *b |= mask; + else + *b &= ~mask; + b++; + } + /* + * Log any remaining changed bytes. + */ + if (b > first) + xfs_trans_log_buf(tp, bp, (uint)((char *)first - (char *)bufp), + (uint)((char *)b - (char *)bufp - 1)); + return 0; +} + +/* + * Mark an extent specified by start and len freed. + * Updates all the summary information as well as the bitmap. + */ +int +xfs_rtfree_range( + xfs_mount_t *mp, /* file system mount point */ + xfs_trans_t *tp, /* transaction pointer */ + xfs_rtblock_t start, /* starting block to free */ + xfs_extlen_t len, /* length to free */ + xfs_buf_t **rbpp, /* in/out: summary block buffer */ + xfs_fsblock_t *rsb) /* in/out: summary block number */ +{ + xfs_rtblock_t end; /* end of the freed extent */ + int error; /* error value */ + xfs_rtblock_t postblock; /* first block freed > end */ + xfs_rtblock_t preblock; /* first block freed < start */ + + end = start + len - 1; + /* + * Modify the bitmap to mark this extent freed. + */ + error = xfs_rtmodify_range(mp, tp, start, len, 1); + if (error) { + return error; + } + /* + * Assume we're freeing out of the middle of an allocated extent. + * We need to find the beginning and end of the extent so we can + * properly update the summary. + */ + error = xfs_rtfind_back(mp, tp, start, 0, &preblock); + if (error) { + return error; + } + /* + * Find the next allocated block (end of allocated extent). + */ + error = xfs_rtfind_forw(mp, tp, end, mp->m_sb.sb_rextents - 1, + &postblock); + if (error) + return error; + /* + * If there are blocks not being freed at the front of the + * old extent, add summary data for them to be allocated. + */ + if (preblock < start) { + error = xfs_rtmodify_summary(mp, tp, + XFS_RTBLOCKLOG(start - preblock), + XFS_BITTOBLOCK(mp, preblock), -1, rbpp, rsb); + if (error) { + return error; + } + } + /* + * If there are blocks not being freed at the end of the + * old extent, add summary data for them to be allocated. + */ + if (postblock > end) { + error = xfs_rtmodify_summary(mp, tp, + XFS_RTBLOCKLOG(postblock - end), + XFS_BITTOBLOCK(mp, end + 1), -1, rbpp, rsb); + if (error) { + return error; + } + } + /* + * Increment the summary information corresponding to the entire + * (new) free extent. + */ + error = xfs_rtmodify_summary(mp, tp, + XFS_RTBLOCKLOG(postblock + 1 - preblock), + XFS_BITTOBLOCK(mp, preblock), 1, rbpp, rsb); + return error; +} + +/* + * Check that the given range is either all allocated (val = 0) or + * all free (val = 1). + */ +int +xfs_rtcheck_range( + xfs_mount_t *mp, /* file system mount point */ + xfs_trans_t *tp, /* transaction pointer */ + xfs_rtblock_t start, /* starting block number of extent */ + xfs_extlen_t len, /* length of extent */ + int val, /* 1 for free, 0 for allocated */ + xfs_rtblock_t *new, /* out: first block 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_rtblock_t block; /* bitmap block number */ + xfs_buf_t *bp; /* buf for the block */ + xfs_rtword_t *bufp; /* starting word in buffer */ + int error; /* error value */ + xfs_rtblock_t i; /* current bit number rel. to start */ + xfs_rtblock_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 */ + int word; /* word number in the buffer */ + + /* + * Compute starting bitmap block number + */ + block = XFS_BITTOBLOCK(mp, start); + /* + * Read the bitmap block. + */ + error = xfs_rtbuf_get(mp, tp, block, 0, &bp); + if (error) { + return error; + } + bufp = bp->b_addr; + /* + * Compute the starting word's address, and starting bit. + */ + word = XFS_BITTOWORD(mp, start); + b = &bufp[word]; + bit = (int)(start & (XFS_NBWORD - 1)); + /* + * 0 (allocated) => all zero's; 1 (free) => all one's. + */ + val = -val; + /* + * If not starting on a word boundary, deal with the first + * (partial) word. + */ + if (bit) { + /* + * Compute first bit not examined. + */ + lastbit = XFS_RTMIN(bit + len, XFS_NBWORD); + /* + * Mask of relevant bits. + */ + mask = (((xfs_rtword_t)1 << (lastbit - bit)) - 1) << bit; + /* + * Compute difference between actual and desired value. + */ + if ((wdiff = (*b ^ val) & mask)) { + /* + * Different, compute first wrong bit and return. + */ + xfs_trans_brelse(tp, bp); + i = XFS_RTLOBIT(wdiff) - bit; + *new = start + i; + *stat = 0; + return 0; + } + i = lastbit - bit; + /* + * Go on to next block if that's where the next word is + * and we need the next word. + */ + if (++word == XFS_BLOCKWSIZE(mp) && i < len) { + /* + * If done with this block, get the next one. + */ + xfs_trans_brelse(tp, bp); + error = xfs_rtbuf_get(mp, tp, ++block, 0, &bp); + if (error) { + return error; + } + b = bufp = bp->b_addr; + word = 0; + } else { + /* + * Go on to the next word in the buffer. + */ + b++; + } + } else { + /* + * Starting on a word boundary, no partial word. + */ + i = 0; + } + /* + * Loop over whole words in buffers. When we use up one buffer + * we move on to the next one. + */ + while (len - i >= XFS_NBWORD) { + /* + * Compute difference between actual and desired value. + */ + if ((wdiff = *b ^ val)) { + /* + * Different, compute first wrong bit and return. + */ + xfs_trans_brelse(tp, bp); + i += XFS_RTLOBIT(wdiff); + *new = start + i; + *stat = 0; + return 0; + } + i += XFS_NBWORD; + /* + * Go on to next block if that's where the next word is + * and we need the next word. + */ + if (++word == XFS_BLOCKWSIZE(mp) && i < len) { + /* + * If done with this block, get the next one. + */ + xfs_trans_brelse(tp, bp); + error = xfs_rtbuf_get(mp, tp, ++block, 0, &bp); + if (error) { + return error; + } + b = bufp = bp->b_addr; + word = 0; + } else { + /* + * Go on to the next word in the buffer. + */ + b++; + } + } + /* + * If not ending on a word boundary, deal with the last + * (partial) word. + */ + if ((lastbit = len - i)) { + /* + * Mask of relevant bits. + */ + mask = ((xfs_rtword_t)1 << lastbit) - 1; + /* + * Compute difference between actual and desired value. + */ + if ((wdiff = (*b ^ val) & mask)) { + /* + * Different, compute first wrong bit and return. + */ + xfs_trans_brelse(tp, bp); + i += XFS_RTLOBIT(wdiff); + *new = start + i; + *stat = 0; + return 0; + } else + i = len; + } + /* + * Successful, return. + */ + xfs_trans_brelse(tp, bp); + *new = start + i; + *stat = 1; + return 0; +} + +#ifdef DEBUG +/* + * Check that the given extent (block range) is allocated already. + */ +STATIC int /* error */ +xfs_rtcheck_alloc_range( + xfs_mount_t *mp, /* file system mount point */ + xfs_trans_t *tp, /* transaction pointer */ + xfs_rtblock_t bno, /* starting block number of extent */ + xfs_extlen_t len) /* length of extent */ +{ + xfs_rtblock_t new; /* dummy for xfs_rtcheck_range */ + int stat; + int error; + + error = xfs_rtcheck_range(mp, tp, bno, len, 0, &new, &stat); + if (error) + return error; + ASSERT(stat); + return 0; +} +#else +#define xfs_rtcheck_alloc_range(m,t,b,l) (0) +#endif +/* + * Free an extent in the realtime subvolume. Length is expressed in + * realtime extents, as is the block number. + */ +int /* error */ +xfs_rtfree_extent( + xfs_trans_t *tp, /* transaction pointer */ + xfs_rtblock_t bno, /* starting block number to free */ + xfs_extlen_t len) /* length of extent freed */ +{ + int error; /* error value */ + xfs_mount_t *mp; /* file system mount structure */ + xfs_fsblock_t sb; /* summary file block number */ + xfs_buf_t *sumbp = NULL; /* summary file block buffer */ + + mp = tp->t_mountp; + + ASSERT(mp->m_rbmip->i_itemp != NULL); + ASSERT(xfs_isilocked(mp->m_rbmip, XFS_ILOCK_EXCL)); + + error = xfs_rtcheck_alloc_range(mp, tp, bno, len); + if (error) + return error; + + /* + * Free the range of realtime blocks. + */ + error = xfs_rtfree_range(mp, tp, bno, len, &sumbp, &sb); + if (error) { + return error; + } + /* + * Mark more blocks free in the superblock. + */ + xfs_trans_mod_sb(tp, XFS_TRANS_SB_FREXTENTS, (long)len); + /* + * If we've now freed all the blocks, reset the file sequence + * number to 0. + */ + if (tp->t_frextents_delta + mp->m_sb.sb_frextents == + mp->m_sb.sb_rextents) { + if (!(mp->m_rbmip->i_d.di_flags & XFS_DIFLAG_NEWRTBM)) + mp->m_rbmip->i_d.di_flags |= XFS_DIFLAG_NEWRTBM; + *(__uint64_t *)&mp->m_rbmip->i_d.di_atime = 0; + xfs_trans_log_inode(tp, mp->m_rbmip, XFS_ILOG_CORE); + } + return 0; +} + |