aboutsummaryrefslogtreecommitdiffstats
path: root/fs/xfs/xfs_rtbitmap.c
diff options
context:
space:
mode:
Diffstat (limited to 'fs/xfs/xfs_rtbitmap.c')
-rw-r--r--fs/xfs/xfs_rtbitmap.c974
1 files changed, 974 insertions, 0 deletions
diff --git a/fs/xfs/xfs_rtbitmap.c b/fs/xfs/xfs_rtbitmap.c
new file mode 100644
index 000000000000..b1f2fe8af4a8
--- /dev/null
+++ b/fs/xfs/xfs_rtbitmap.c
@@ -0,0 +1,974 @@
+/*
+ * 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_sb.h"
+#include "xfs_ag.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_dinode.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;
+ ASSERT(!xfs_buf_geterror(bp));
+ *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 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.
+ */
+int
+xfs_rtmodify_summary(
+ xfs_mount_t *mp, /* file system mount point */
+ 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_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 && *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 && *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.
+ */
+ if (rbpp) {
+ *rbpp = bp;
+ *rsb = sb;
+ }
+ }
+ /*
+ * Point to the summary information, modify and log it.
+ */
+ sp = XFS_SUMPTR(mp, bp, so);
+ *sp += delta;
+ xfs_trans_log_buf(tp, bp, (uint)((char *)sp - (char *)bp->b_addr),
+ (uint)((char *)sp - (char *)bp->b_addr + sizeof(*sp) - 1));
+ return 0;
+}
+
+/*
+ * 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;
+}
+
Copyright © 1996 – 2023 Jason A. Donenfeld. All Rights Reverse Engineered.