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-rw-r--r--fs/xfs/xfs_rtalloc.c1409
1 files changed, 1409 insertions, 0 deletions
diff --git a/fs/xfs/xfs_rtalloc.c b/fs/xfs/xfs_rtalloc.c
new file mode 100644
index 000000000..292d5e54a
--- /dev/null
+++ b/fs/xfs/xfs_rtalloc.c
@@ -0,0 +1,1409 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * Copyright (c) 2000-2005 Silicon Graphics, Inc.
+ * All Rights Reserved.
+ */
+#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_btree.h"
+#include "xfs_trans.h"
+#include "xfs_trans_space.h"
+#include "xfs_icache.h"
+#include "xfs_rtalloc.h"
+#include "xfs_sb.h"
+
+/*
+ * Read and return 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.
+ */
+static int
+xfs_rtget_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 */
+ struct xfs_buf **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 */
+{
+ return xfs_rtmodify_summary_int(mp, tp, log, bbno, 0, rbpp, rsb, sum);
+}
+
+/*
+ * Return whether there are any free extents in the size range given
+ * by low and high, for the bitmap block bbno.
+ */
+STATIC int /* error */
+xfs_rtany_summary(
+ xfs_mount_t *mp, /* file system mount structure */
+ xfs_trans_t *tp, /* transaction pointer */
+ int low, /* low log2 extent size */
+ int high, /* high log2 extent size */
+ xfs_rtblock_t bbno, /* bitmap block number */
+ struct xfs_buf **rbpp, /* in/out: summary block buffer */
+ xfs_fsblock_t *rsb, /* in/out: summary block number */
+ int *stat) /* out: any good extents here? */
+{
+ int error; /* error value */
+ int log; /* loop counter, log2 of ext. size */
+ xfs_suminfo_t sum; /* summary data */
+
+ /* There are no extents at levels < m_rsum_cache[bbno]. */
+ if (mp->m_rsum_cache && low < mp->m_rsum_cache[bbno])
+ low = mp->m_rsum_cache[bbno];
+
+ /*
+ * Loop over logs of extent sizes.
+ */
+ for (log = low; log <= high; log++) {
+ /*
+ * Get one summary datum.
+ */
+ error = xfs_rtget_summary(mp, tp, log, bbno, rbpp, rsb, &sum);
+ if (error) {
+ return error;
+ }
+ /*
+ * If there are any, return success.
+ */
+ if (sum) {
+ *stat = 1;
+ goto out;
+ }
+ }
+ /*
+ * Found nothing, return failure.
+ */
+ *stat = 0;
+out:
+ /* There were no extents at levels < log. */
+ if (mp->m_rsum_cache && log > mp->m_rsum_cache[bbno])
+ mp->m_rsum_cache[bbno] = log;
+ return 0;
+}
+
+
+/*
+ * Copy and transform the summary file, given the old and new
+ * parameters in the mount structures.
+ */
+STATIC int /* error */
+xfs_rtcopy_summary(
+ xfs_mount_t *omp, /* old file system mount point */
+ xfs_mount_t *nmp, /* new file system mount point */
+ xfs_trans_t *tp) /* transaction pointer */
+{
+ xfs_rtblock_t bbno; /* bitmap block number */
+ struct xfs_buf *bp; /* summary buffer */
+ int error; /* error return value */
+ int log; /* summary level number (log length) */
+ xfs_suminfo_t sum; /* summary data */
+ xfs_fsblock_t sumbno; /* summary block number */
+
+ bp = NULL;
+ for (log = omp->m_rsumlevels - 1; log >= 0; log--) {
+ for (bbno = omp->m_sb.sb_rbmblocks - 1;
+ (xfs_srtblock_t)bbno >= 0;
+ bbno--) {
+ error = xfs_rtget_summary(omp, tp, log, bbno, &bp,
+ &sumbno, &sum);
+ if (error)
+ return error;
+ if (sum == 0)
+ continue;
+ error = xfs_rtmodify_summary(omp, tp, log, bbno, -sum,
+ &bp, &sumbno);
+ if (error)
+ return error;
+ error = xfs_rtmodify_summary(nmp, tp, log, bbno, sum,
+ &bp, &sumbno);
+ if (error)
+ return error;
+ ASSERT(sum > 0);
+ }
+ }
+ return 0;
+}
+/*
+ * Mark an extent specified by start and len allocated.
+ * Updates all the summary information as well as the bitmap.
+ */
+STATIC int /* error */
+xfs_rtallocate_range(
+ xfs_mount_t *mp, /* file system mount point */
+ xfs_trans_t *tp, /* transaction pointer */
+ xfs_rtblock_t start, /* start block to allocate */
+ xfs_extlen_t len, /* length to allocate */
+ struct xfs_buf **rbpp, /* in/out: summary block buffer */
+ xfs_fsblock_t *rsb) /* in/out: summary block number */
+{
+ xfs_rtblock_t end; /* end of the allocated extent */
+ int error; /* error value */
+ xfs_rtblock_t postblock = 0; /* first block allocated > end */
+ xfs_rtblock_t preblock = 0; /* first block allocated < start */
+
+ end = start + len - 1;
+ /*
+ * Assume we're allocating out of the middle of a free 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 free extent).
+ */
+ error = xfs_rtfind_forw(mp, tp, end, mp->m_sb.sb_rextents - 1,
+ &postblock);
+ if (error) {
+ return error;
+ }
+ /*
+ * Decrement the summary information corresponding to the entire
+ * (old) free extent.
+ */
+ error = xfs_rtmodify_summary(mp, tp,
+ XFS_RTBLOCKLOG(postblock + 1 - preblock),
+ XFS_BITTOBLOCK(mp, preblock), -1, rbpp, rsb);
+ if (error) {
+ return error;
+ }
+ /*
+ * If there are blocks not being allocated at the front of the
+ * old extent, add summary data for them to be free.
+ */
+ 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 allocated at the end of the
+ * old extent, add summary data for them to be free.
+ */
+ 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;
+ }
+ }
+ /*
+ * Modify the bitmap to mark this extent allocated.
+ */
+ error = xfs_rtmodify_range(mp, tp, start, len, 0);
+ return error;
+}
+
+/*
+ * Attempt to allocate an extent minlen<=len<=maxlen starting from
+ * bitmap block bbno. If we don't get maxlen then use prod to trim
+ * the length, if given. Returns error; returns starting block in *rtblock.
+ * The lengths are all in rtextents.
+ */
+STATIC int /* error */
+xfs_rtallocate_extent_block(
+ xfs_mount_t *mp, /* file system mount point */
+ xfs_trans_t *tp, /* transaction pointer */
+ xfs_rtblock_t bbno, /* bitmap block number */
+ xfs_extlen_t minlen, /* minimum length to allocate */
+ xfs_extlen_t maxlen, /* maximum length to allocate */
+ xfs_extlen_t *len, /* out: actual length allocated */
+ xfs_rtblock_t *nextp, /* out: next block to try */
+ struct xfs_buf **rbpp, /* in/out: summary block buffer */
+ xfs_fsblock_t *rsb, /* in/out: summary block number */
+ xfs_extlen_t prod, /* extent product factor */
+ xfs_rtblock_t *rtblock) /* out: start block allocated */
+{
+ xfs_rtblock_t besti; /* best rtblock found so far */
+ xfs_rtblock_t bestlen; /* best length found so far */
+ xfs_rtblock_t end; /* last rtblock in chunk */
+ int error; /* error value */
+ xfs_rtblock_t i; /* current rtblock trying */
+ xfs_rtblock_t next; /* next rtblock to try */
+ int stat; /* status from internal calls */
+
+ /*
+ * Loop over all the extents starting in this bitmap block,
+ * looking for one that's long enough.
+ */
+ for (i = XFS_BLOCKTOBIT(mp, bbno), besti = -1, bestlen = 0,
+ end = XFS_BLOCKTOBIT(mp, bbno + 1) - 1;
+ i <= end;
+ i++) {
+ /* Make sure we don't scan off the end of the rt volume. */
+ maxlen = min(mp->m_sb.sb_rextents, i + maxlen) - i;
+
+ /*
+ * See if there's a free extent of maxlen starting at i.
+ * If it's not so then next will contain the first non-free.
+ */
+ error = xfs_rtcheck_range(mp, tp, i, maxlen, 1, &next, &stat);
+ if (error) {
+ return error;
+ }
+ if (stat) {
+ /*
+ * i for maxlen is all free, allocate and return that.
+ */
+ error = xfs_rtallocate_range(mp, tp, i, maxlen, rbpp,
+ rsb);
+ if (error) {
+ return error;
+ }
+ *len = maxlen;
+ *rtblock = i;
+ return 0;
+ }
+ /*
+ * In the case where we have a variable-sized allocation
+ * request, figure out how big this free piece is,
+ * and if it's big enough for the minimum, and the best
+ * so far, remember it.
+ */
+ if (minlen < maxlen) {
+ xfs_rtblock_t thislen; /* this extent size */
+
+ thislen = next - i;
+ if (thislen >= minlen && thislen > bestlen) {
+ besti = i;
+ bestlen = thislen;
+ }
+ }
+ /*
+ * If not done yet, find the start of the next free space.
+ */
+ if (next < end) {
+ error = xfs_rtfind_forw(mp, tp, next, end, &i);
+ if (error) {
+ return error;
+ }
+ } else
+ break;
+ }
+ /*
+ * Searched the whole thing & didn't find a maxlen free extent.
+ */
+ if (minlen < maxlen && besti != -1) {
+ xfs_extlen_t p; /* amount to trim length by */
+
+ /*
+ * If size should be a multiple of prod, make that so.
+ */
+ if (prod > 1) {
+ div_u64_rem(bestlen, prod, &p);
+ if (p)
+ bestlen -= p;
+ }
+
+ /*
+ * Allocate besti for bestlen & return that.
+ */
+ error = xfs_rtallocate_range(mp, tp, besti, bestlen, rbpp, rsb);
+ if (error) {
+ return error;
+ }
+ *len = bestlen;
+ *rtblock = besti;
+ return 0;
+ }
+ /*
+ * Allocation failed. Set *nextp to the next block to try.
+ */
+ *nextp = next;
+ *rtblock = NULLRTBLOCK;
+ return 0;
+}
+
+/*
+ * Allocate an extent of length minlen<=len<=maxlen, starting at block
+ * bno. If we don't get maxlen then use prod to trim the length, if given.
+ * Returns error; returns starting block in *rtblock.
+ * The lengths are all in rtextents.
+ */
+STATIC int /* error */
+xfs_rtallocate_extent_exact(
+ xfs_mount_t *mp, /* file system mount point */
+ xfs_trans_t *tp, /* transaction pointer */
+ xfs_rtblock_t bno, /* starting block number to allocate */
+ xfs_extlen_t minlen, /* minimum length to allocate */
+ xfs_extlen_t maxlen, /* maximum length to allocate */
+ xfs_extlen_t *len, /* out: actual length allocated */
+ struct xfs_buf **rbpp, /* in/out: summary block buffer */
+ xfs_fsblock_t *rsb, /* in/out: summary block number */
+ xfs_extlen_t prod, /* extent product factor */
+ xfs_rtblock_t *rtblock) /* out: start block allocated */
+{
+ int error; /* error value */
+ xfs_extlen_t i; /* extent length trimmed due to prod */
+ int isfree; /* extent is free */
+ xfs_rtblock_t next; /* next block to try (dummy) */
+
+ ASSERT(minlen % prod == 0 && maxlen % prod == 0);
+ /*
+ * Check if the range in question (for maxlen) is free.
+ */
+ error = xfs_rtcheck_range(mp, tp, bno, maxlen, 1, &next, &isfree);
+ if (error) {
+ return error;
+ }
+ if (isfree) {
+ /*
+ * If it is, allocate it and return success.
+ */
+ error = xfs_rtallocate_range(mp, tp, bno, maxlen, rbpp, rsb);
+ if (error) {
+ return error;
+ }
+ *len = maxlen;
+ *rtblock = bno;
+ return 0;
+ }
+ /*
+ * If not, allocate what there is, if it's at least minlen.
+ */
+ maxlen = next - bno;
+ if (maxlen < minlen) {
+ /*
+ * Failed, return failure status.
+ */
+ *rtblock = NULLRTBLOCK;
+ return 0;
+ }
+ /*
+ * Trim off tail of extent, if prod is specified.
+ */
+ if (prod > 1 && (i = maxlen % prod)) {
+ maxlen -= i;
+ if (maxlen < minlen) {
+ /*
+ * Now we can't do it, return failure status.
+ */
+ *rtblock = NULLRTBLOCK;
+ return 0;
+ }
+ }
+ /*
+ * Allocate what we can and return it.
+ */
+ error = xfs_rtallocate_range(mp, tp, bno, maxlen, rbpp, rsb);
+ if (error) {
+ return error;
+ }
+ *len = maxlen;
+ *rtblock = bno;
+ return 0;
+}
+
+/*
+ * Allocate an extent of length minlen<=len<=maxlen, starting as near
+ * to bno as possible. If we don't get maxlen then use prod to trim
+ * the length, if given. The lengths are all in rtextents.
+ */
+STATIC int /* error */
+xfs_rtallocate_extent_near(
+ xfs_mount_t *mp, /* file system mount point */
+ xfs_trans_t *tp, /* transaction pointer */
+ xfs_rtblock_t bno, /* starting block number to allocate */
+ xfs_extlen_t minlen, /* minimum length to allocate */
+ xfs_extlen_t maxlen, /* maximum length to allocate */
+ xfs_extlen_t *len, /* out: actual length allocated */
+ struct xfs_buf **rbpp, /* in/out: summary block buffer */
+ xfs_fsblock_t *rsb, /* in/out: summary block number */
+ xfs_extlen_t prod, /* extent product factor */
+ xfs_rtblock_t *rtblock) /* out: start block allocated */
+{
+ int any; /* any useful extents from summary */
+ xfs_rtblock_t bbno; /* bitmap block number */
+ int error; /* error value */
+ int i; /* bitmap block offset (loop control) */
+ int j; /* secondary loop control */
+ int log2len; /* log2 of minlen */
+ xfs_rtblock_t n; /* next block to try */
+ xfs_rtblock_t r; /* result block */
+
+ ASSERT(minlen % prod == 0 && maxlen % prod == 0);
+ /*
+ * If the block number given is off the end, silently set it to
+ * the last block.
+ */
+ if (bno >= mp->m_sb.sb_rextents)
+ bno = mp->m_sb.sb_rextents - 1;
+
+ /* Make sure we don't run off the end of the rt volume. */
+ maxlen = min(mp->m_sb.sb_rextents, bno + maxlen) - bno;
+ if (maxlen < minlen) {
+ *rtblock = NULLRTBLOCK;
+ return 0;
+ }
+
+ /*
+ * Try the exact allocation first.
+ */
+ error = xfs_rtallocate_extent_exact(mp, tp, bno, minlen, maxlen, len,
+ rbpp, rsb, prod, &r);
+ if (error) {
+ return error;
+ }
+ /*
+ * If the exact allocation worked, return that.
+ */
+ if (r != NULLRTBLOCK) {
+ *rtblock = r;
+ return 0;
+ }
+ bbno = XFS_BITTOBLOCK(mp, bno);
+ i = 0;
+ ASSERT(minlen != 0);
+ log2len = xfs_highbit32(minlen);
+ /*
+ * Loop over all bitmap blocks (bbno + i is current block).
+ */
+ for (;;) {
+ /*
+ * Get summary information of extents of all useful levels
+ * starting in this bitmap block.
+ */
+ error = xfs_rtany_summary(mp, tp, log2len, mp->m_rsumlevels - 1,
+ bbno + i, rbpp, rsb, &any);
+ if (error) {
+ return error;
+ }
+ /*
+ * If there are any useful extents starting here, try
+ * allocating one.
+ */
+ if (any) {
+ /*
+ * On the positive side of the starting location.
+ */
+ if (i >= 0) {
+ /*
+ * Try to allocate an extent starting in
+ * this block.
+ */
+ error = xfs_rtallocate_extent_block(mp, tp,
+ bbno + i, minlen, maxlen, len, &n, rbpp,
+ rsb, prod, &r);
+ if (error) {
+ return error;
+ }
+ /*
+ * If it worked, return it.
+ */
+ if (r != NULLRTBLOCK) {
+ *rtblock = r;
+ return 0;
+ }
+ }
+ /*
+ * On the negative side of the starting location.
+ */
+ else { /* i < 0 */
+ /*
+ * Loop backwards through the bitmap blocks from
+ * the starting point-1 up to where we are now.
+ * There should be an extent which ends in this
+ * bitmap block and is long enough.
+ */
+ for (j = -1; j > i; j--) {
+ /*
+ * Grab the summary information for
+ * this bitmap block.
+ */
+ error = xfs_rtany_summary(mp, tp,
+ log2len, mp->m_rsumlevels - 1,
+ bbno + j, rbpp, rsb, &any);
+ if (error) {
+ return error;
+ }
+ /*
+ * If there's no extent given in the
+ * summary that means the extent we
+ * found must carry over from an
+ * earlier block. If there is an
+ * extent given, we've already tried
+ * that allocation, don't do it again.
+ */
+ if (any)
+ continue;
+ error = xfs_rtallocate_extent_block(mp,
+ tp, bbno + j, minlen, maxlen,
+ len, &n, rbpp, rsb, prod, &r);
+ if (error) {
+ return error;
+ }
+ /*
+ * If it works, return the extent.
+ */
+ if (r != NULLRTBLOCK) {
+ *rtblock = r;
+ return 0;
+ }
+ }
+ /*
+ * There weren't intervening bitmap blocks
+ * with a long enough extent, or the
+ * allocation didn't work for some reason
+ * (i.e. it's a little * too short).
+ * Try to allocate from the summary block
+ * that we found.
+ */
+ error = xfs_rtallocate_extent_block(mp, tp,
+ bbno + i, minlen, maxlen, len, &n, rbpp,
+ rsb, prod, &r);
+ if (error) {
+ return error;
+ }
+ /*
+ * If it works, return the extent.
+ */
+ if (r != NULLRTBLOCK) {
+ *rtblock = r;
+ return 0;
+ }
+ }
+ }
+ /*
+ * Loop control. If we were on the positive side, and there's
+ * still more blocks on the negative side, go there.
+ */
+ if (i > 0 && (int)bbno - i >= 0)
+ i = -i;
+ /*
+ * If positive, and no more negative, but there are more
+ * positive, go there.
+ */
+ else if (i > 0 && (int)bbno + i < mp->m_sb.sb_rbmblocks - 1)
+ i++;
+ /*
+ * If negative or 0 (just started), and there are positive
+ * blocks to go, go there. The 0 case moves to block 1.
+ */
+ else if (i <= 0 && (int)bbno - i < mp->m_sb.sb_rbmblocks - 1)
+ i = 1 - i;
+ /*
+ * If negative or 0 and there are more negative blocks,
+ * go there.
+ */
+ else if (i <= 0 && (int)bbno + i > 0)
+ i--;
+ /*
+ * Must be done. Return failure.
+ */
+ else
+ break;
+ }
+ *rtblock = NULLRTBLOCK;
+ return 0;
+}
+
+/*
+ * Allocate an extent of length minlen<=len<=maxlen, with no position
+ * specified. If we don't get maxlen then use prod to trim
+ * the length, if given. The lengths are all in rtextents.
+ */
+STATIC int /* error */
+xfs_rtallocate_extent_size(
+ xfs_mount_t *mp, /* file system mount point */
+ xfs_trans_t *tp, /* transaction pointer */
+ xfs_extlen_t minlen, /* minimum length to allocate */
+ xfs_extlen_t maxlen, /* maximum length to allocate */
+ xfs_extlen_t *len, /* out: actual length allocated */
+ struct xfs_buf **rbpp, /* in/out: summary block buffer */
+ xfs_fsblock_t *rsb, /* in/out: summary block number */
+ xfs_extlen_t prod, /* extent product factor */
+ xfs_rtblock_t *rtblock) /* out: start block allocated */
+{
+ int error; /* error value */
+ int i; /* bitmap block number */
+ int l; /* level number (loop control) */
+ xfs_rtblock_t n; /* next block to be tried */
+ xfs_rtblock_t r; /* result block number */
+ xfs_suminfo_t sum; /* summary information for extents */
+
+ ASSERT(minlen % prod == 0 && maxlen % prod == 0);
+ ASSERT(maxlen != 0);
+
+ /*
+ * Loop over all the levels starting with maxlen.
+ * At each level, look at all the bitmap blocks, to see if there
+ * are extents starting there that are long enough (>= maxlen).
+ * Note, only on the initial level can the allocation fail if
+ * the summary says there's an extent.
+ */
+ for (l = xfs_highbit32(maxlen); l < mp->m_rsumlevels; l++) {
+ /*
+ * Loop over all the bitmap blocks.
+ */
+ for (i = 0; i < mp->m_sb.sb_rbmblocks; i++) {
+ /*
+ * Get the summary for this level/block.
+ */
+ error = xfs_rtget_summary(mp, tp, l, i, rbpp, rsb,
+ &sum);
+ if (error) {
+ return error;
+ }
+ /*
+ * Nothing there, on to the next block.
+ */
+ if (!sum)
+ continue;
+ /*
+ * Try allocating the extent.
+ */
+ error = xfs_rtallocate_extent_block(mp, tp, i, maxlen,
+ maxlen, len, &n, rbpp, rsb, prod, &r);
+ if (error) {
+ return error;
+ }
+ /*
+ * If it worked, return that.
+ */
+ if (r != NULLRTBLOCK) {
+ *rtblock = r;
+ return 0;
+ }
+ /*
+ * If the "next block to try" returned from the
+ * allocator is beyond the next bitmap block,
+ * skip to that bitmap block.
+ */
+ if (XFS_BITTOBLOCK(mp, n) > i + 1)
+ i = XFS_BITTOBLOCK(mp, n) - 1;
+ }
+ }
+ /*
+ * Didn't find any maxlen blocks. Try smaller ones, unless
+ * we're asking for a fixed size extent.
+ */
+ if (minlen > --maxlen) {
+ *rtblock = NULLRTBLOCK;
+ return 0;
+ }
+ ASSERT(minlen != 0);
+ ASSERT(maxlen != 0);
+
+ /*
+ * Loop over sizes, from maxlen down to minlen.
+ * This time, when we do the allocations, allow smaller ones
+ * to succeed.
+ */
+ for (l = xfs_highbit32(maxlen); l >= xfs_highbit32(minlen); l--) {
+ /*
+ * Loop over all the bitmap blocks, try an allocation
+ * starting in that block.
+ */
+ for (i = 0; i < mp->m_sb.sb_rbmblocks; i++) {
+ /*
+ * Get the summary information for this level/block.
+ */
+ error = xfs_rtget_summary(mp, tp, l, i, rbpp, rsb,
+ &sum);
+ if (error) {
+ return error;
+ }
+ /*
+ * If nothing there, go on to next.
+ */
+ if (!sum)
+ continue;
+ /*
+ * Try the allocation. Make sure the specified
+ * minlen/maxlen are in the possible range for
+ * this summary level.
+ */
+ error = xfs_rtallocate_extent_block(mp, tp, i,
+ XFS_RTMAX(minlen, 1 << l),
+ XFS_RTMIN(maxlen, (1 << (l + 1)) - 1),
+ len, &n, rbpp, rsb, prod, &r);
+ if (error) {
+ return error;
+ }
+ /*
+ * If it worked, return that extent.
+ */
+ if (r != NULLRTBLOCK) {
+ *rtblock = r;
+ return 0;
+ }
+ /*
+ * If the "next block to try" returned from the
+ * allocator is beyond the next bitmap block,
+ * skip to that bitmap block.
+ */
+ if (XFS_BITTOBLOCK(mp, n) > i + 1)
+ i = XFS_BITTOBLOCK(mp, n) - 1;
+ }
+ }
+ /*
+ * Got nothing, return failure.
+ */
+ *rtblock = NULLRTBLOCK;
+ return 0;
+}
+
+/*
+ * Allocate space to the bitmap or summary file, and zero it, for growfs.
+ */
+STATIC int
+xfs_growfs_rt_alloc(
+ struct xfs_mount *mp, /* file system mount point */
+ xfs_extlen_t oblocks, /* old count of blocks */
+ xfs_extlen_t nblocks, /* new count of blocks */
+ struct xfs_inode *ip) /* inode (bitmap/summary) */
+{
+ xfs_fileoff_t bno; /* block number in file */
+ struct xfs_buf *bp; /* temporary buffer for zeroing */
+ xfs_daddr_t d; /* disk block address */
+ int error; /* error return value */
+ xfs_fsblock_t fsbno; /* filesystem block for bno */
+ struct xfs_bmbt_irec map; /* block map output */
+ int nmap; /* number of block maps */
+ int resblks; /* space reservation */
+ enum xfs_blft buf_type;
+ struct xfs_trans *tp;
+
+ if (ip == mp->m_rsumip)
+ buf_type = XFS_BLFT_RTSUMMARY_BUF;
+ else
+ buf_type = XFS_BLFT_RTBITMAP_BUF;
+
+ /*
+ * Allocate space to the file, as necessary.
+ */
+ while (oblocks < nblocks) {
+ resblks = XFS_GROWFSRT_SPACE_RES(mp, nblocks - oblocks);
+ /*
+ * Reserve space & log for one extent added to the file.
+ */
+ error = xfs_trans_alloc(mp, &M_RES(mp)->tr_growrtalloc, resblks,
+ 0, 0, &tp);
+ if (error)
+ return error;
+ /*
+ * Lock the inode.
+ */
+ xfs_ilock(ip, XFS_ILOCK_EXCL);
+ xfs_trans_ijoin(tp, ip, XFS_ILOCK_EXCL);
+
+ error = xfs_iext_count_may_overflow(ip, XFS_DATA_FORK,
+ XFS_IEXT_ADD_NOSPLIT_CNT);
+ if (error == -EFBIG)
+ error = xfs_iext_count_upgrade(tp, ip,
+ XFS_IEXT_ADD_NOSPLIT_CNT);
+ if (error)
+ goto out_trans_cancel;
+
+ /*
+ * Allocate blocks to the bitmap file.
+ */
+ nmap = 1;
+ error = xfs_bmapi_write(tp, ip, oblocks, nblocks - oblocks,
+ XFS_BMAPI_METADATA, 0, &map, &nmap);
+ if (!error && nmap < 1)
+ error = -ENOSPC;
+ if (error)
+ goto out_trans_cancel;
+ /*
+ * Free any blocks freed up in the transaction, then commit.
+ */
+ error = xfs_trans_commit(tp);
+ if (error)
+ return error;
+ /*
+ * Now we need to clear the allocated blocks.
+ * Do this one block per transaction, to keep it simple.
+ */
+ for (bno = map.br_startoff, fsbno = map.br_startblock;
+ bno < map.br_startoff + map.br_blockcount;
+ bno++, fsbno++) {
+ /*
+ * Reserve log for one block zeroing.
+ */
+ error = xfs_trans_alloc(mp, &M_RES(mp)->tr_growrtzero,
+ 0, 0, 0, &tp);
+ if (error)
+ return error;
+ /*
+ * Lock the bitmap inode.
+ */
+ xfs_ilock(ip, XFS_ILOCK_EXCL);
+ xfs_trans_ijoin(tp, ip, XFS_ILOCK_EXCL);
+ /*
+ * Get a buffer for the block.
+ */
+ d = XFS_FSB_TO_DADDR(mp, fsbno);
+ error = xfs_trans_get_buf(tp, mp->m_ddev_targp, d,
+ mp->m_bsize, 0, &bp);
+ if (error)
+ goto out_trans_cancel;
+
+ xfs_trans_buf_set_type(tp, bp, buf_type);
+ bp->b_ops = &xfs_rtbuf_ops;
+ memset(bp->b_addr, 0, mp->m_sb.sb_blocksize);
+ xfs_trans_log_buf(tp, bp, 0, mp->m_sb.sb_blocksize - 1);
+ /*
+ * Commit the transaction.
+ */
+ error = xfs_trans_commit(tp);
+ if (error)
+ return error;
+ }
+ /*
+ * Go on to the next extent, if any.
+ */
+ oblocks = map.br_startoff + map.br_blockcount;
+ }
+
+ return 0;
+
+out_trans_cancel:
+ xfs_trans_cancel(tp);
+ return error;
+}
+
+static void
+xfs_alloc_rsum_cache(
+ xfs_mount_t *mp, /* file system mount structure */
+ xfs_extlen_t rbmblocks) /* number of rt bitmap blocks */
+{
+ /*
+ * The rsum cache is initialized to all zeroes, which is trivially a
+ * lower bound on the minimum level with any free extents. We can
+ * continue without the cache if it couldn't be allocated.
+ */
+ mp->m_rsum_cache = kvzalloc(rbmblocks, GFP_KERNEL);
+ if (!mp->m_rsum_cache)
+ xfs_warn(mp, "could not allocate realtime summary cache");
+}
+
+/*
+ * Visible (exported) functions.
+ */
+
+/*
+ * Grow the realtime area of the filesystem.
+ */
+int
+xfs_growfs_rt(
+ xfs_mount_t *mp, /* mount point for filesystem */
+ xfs_growfs_rt_t *in) /* growfs rt input struct */
+{
+ xfs_rtblock_t bmbno; /* bitmap block number */
+ struct xfs_buf *bp; /* temporary buffer */
+ int error; /* error return value */
+ xfs_mount_t *nmp; /* new (fake) mount structure */
+ xfs_rfsblock_t nrblocks; /* new number of realtime blocks */
+ xfs_extlen_t nrbmblocks; /* new number of rt bitmap blocks */
+ xfs_rtblock_t nrextents; /* new number of realtime extents */
+ uint8_t nrextslog; /* new log2 of sb_rextents */
+ xfs_extlen_t nrsumblocks; /* new number of summary blocks */
+ uint nrsumlevels; /* new rt summary levels */
+ uint nrsumsize; /* new size of rt summary, bytes */
+ xfs_sb_t *nsbp; /* new superblock */
+ xfs_extlen_t rbmblocks; /* current number of rt bitmap blocks */
+ xfs_extlen_t rsumblocks; /* current number of rt summary blks */
+ xfs_sb_t *sbp; /* old superblock */
+ xfs_fsblock_t sumbno; /* summary block number */
+ uint8_t *rsum_cache; /* old summary cache */
+
+ sbp = &mp->m_sb;
+
+ if (!capable(CAP_SYS_ADMIN))
+ return -EPERM;
+
+ /* Needs to have been mounted with an rt device. */
+ if (!XFS_IS_REALTIME_MOUNT(mp))
+ return -EINVAL;
+ /*
+ * Mount should fail if the rt bitmap/summary files don't load, but
+ * we'll check anyway.
+ */
+ if (!mp->m_rbmip || !mp->m_rsumip)
+ return -EINVAL;
+
+ /* Shrink not supported. */
+ if (in->newblocks <= sbp->sb_rblocks)
+ return -EINVAL;
+
+ /* Can only change rt extent size when adding rt volume. */
+ if (sbp->sb_rblocks > 0 && in->extsize != sbp->sb_rextsize)
+ return -EINVAL;
+
+ /* Range check the extent size. */
+ if (XFS_FSB_TO_B(mp, in->extsize) > XFS_MAX_RTEXTSIZE ||
+ XFS_FSB_TO_B(mp, in->extsize) < XFS_MIN_RTEXTSIZE)
+ return -EINVAL;
+
+ /* Unsupported realtime features. */
+ if (xfs_has_rmapbt(mp) || xfs_has_reflink(mp))
+ return -EOPNOTSUPP;
+
+ nrblocks = in->newblocks;
+ error = xfs_sb_validate_fsb_count(sbp, nrblocks);
+ if (error)
+ return error;
+ /*
+ * Read in the last block of the device, make sure it exists.
+ */
+ error = xfs_buf_read_uncached(mp->m_rtdev_targp,
+ XFS_FSB_TO_BB(mp, nrblocks - 1),
+ XFS_FSB_TO_BB(mp, 1), 0, &bp, NULL);
+ if (error)
+ return error;
+ xfs_buf_relse(bp);
+
+ /*
+ * Calculate new parameters. These are the final values to be reached.
+ */
+ nrextents = nrblocks;
+ do_div(nrextents, in->extsize);
+ nrbmblocks = howmany_64(nrextents, NBBY * sbp->sb_blocksize);
+ nrextslog = xfs_highbit32(nrextents);
+ nrsumlevels = nrextslog + 1;
+ nrsumsize = (uint)sizeof(xfs_suminfo_t) * nrsumlevels * nrbmblocks;
+ nrsumblocks = XFS_B_TO_FSB(mp, nrsumsize);
+ nrsumsize = XFS_FSB_TO_B(mp, nrsumblocks);
+ /*
+ * New summary size can't be more than half the size of
+ * the log. This prevents us from getting a log overflow,
+ * since we'll log basically the whole summary file at once.
+ */
+ if (nrsumblocks > (mp->m_sb.sb_logblocks >> 1))
+ return -EINVAL;
+ /*
+ * Get the old block counts for bitmap and summary inodes.
+ * These can't change since other growfs callers are locked out.
+ */
+ rbmblocks = XFS_B_TO_FSB(mp, mp->m_rbmip->i_disk_size);
+ rsumblocks = XFS_B_TO_FSB(mp, mp->m_rsumip->i_disk_size);
+ /*
+ * Allocate space to the bitmap and summary files, as necessary.
+ */
+ error = xfs_growfs_rt_alloc(mp, rbmblocks, nrbmblocks, mp->m_rbmip);
+ if (error)
+ return error;
+ error = xfs_growfs_rt_alloc(mp, rsumblocks, nrsumblocks, mp->m_rsumip);
+ if (error)
+ return error;
+
+ rsum_cache = mp->m_rsum_cache;
+ if (nrbmblocks != sbp->sb_rbmblocks)
+ xfs_alloc_rsum_cache(mp, nrbmblocks);
+
+ /*
+ * Allocate a new (fake) mount/sb.
+ */
+ nmp = kmem_alloc(sizeof(*nmp), 0);
+ /*
+ * Loop over the bitmap blocks.
+ * We will do everything one bitmap block at a time.
+ * Skip the current block if it is exactly full.
+ * This also deals with the case where there were no rtextents before.
+ */
+ for (bmbno = sbp->sb_rbmblocks -
+ ((sbp->sb_rextents & ((1 << mp->m_blkbit_log) - 1)) != 0);
+ bmbno < nrbmblocks;
+ bmbno++) {
+ struct xfs_trans *tp;
+ xfs_rfsblock_t nrblocks_step;
+
+ *nmp = *mp;
+ nsbp = &nmp->m_sb;
+ /*
+ * Calculate new sb and mount fields for this round.
+ */
+ nsbp->sb_rextsize = in->extsize;
+ nsbp->sb_rbmblocks = bmbno + 1;
+ nrblocks_step = (bmbno + 1) * NBBY * nsbp->sb_blocksize *
+ nsbp->sb_rextsize;
+ nsbp->sb_rblocks = min(nrblocks, nrblocks_step);
+ nsbp->sb_rextents = nsbp->sb_rblocks;
+ do_div(nsbp->sb_rextents, nsbp->sb_rextsize);
+ ASSERT(nsbp->sb_rextents != 0);
+ nsbp->sb_rextslog = xfs_highbit32(nsbp->sb_rextents);
+ nrsumlevels = nmp->m_rsumlevels = nsbp->sb_rextslog + 1;
+ nrsumsize =
+ (uint)sizeof(xfs_suminfo_t) * nrsumlevels *
+ nsbp->sb_rbmblocks;
+ nrsumblocks = XFS_B_TO_FSB(mp, nrsumsize);
+ nmp->m_rsumsize = nrsumsize = XFS_FSB_TO_B(mp, nrsumblocks);
+ /*
+ * Start a transaction, get the log reservation.
+ */
+ error = xfs_trans_alloc(mp, &M_RES(mp)->tr_growrtfree, 0, 0, 0,
+ &tp);
+ if (error)
+ break;
+ /*
+ * Lock out other callers by grabbing the bitmap inode lock.
+ */
+ xfs_ilock(mp->m_rbmip, XFS_ILOCK_EXCL | XFS_ILOCK_RTBITMAP);
+ xfs_trans_ijoin(tp, mp->m_rbmip, XFS_ILOCK_EXCL);
+ /*
+ * Update the bitmap inode's size ondisk and incore. We need
+ * to update the incore size so that inode inactivation won't
+ * punch what it thinks are "posteof" blocks.
+ */
+ mp->m_rbmip->i_disk_size =
+ nsbp->sb_rbmblocks * nsbp->sb_blocksize;
+ i_size_write(VFS_I(mp->m_rbmip), mp->m_rbmip->i_disk_size);
+ xfs_trans_log_inode(tp, mp->m_rbmip, XFS_ILOG_CORE);
+ /*
+ * Get the summary inode into the transaction.
+ */
+ xfs_ilock(mp->m_rsumip, XFS_ILOCK_EXCL | XFS_ILOCK_RTSUM);
+ xfs_trans_ijoin(tp, mp->m_rsumip, XFS_ILOCK_EXCL);
+ /*
+ * Update the summary inode's size. We need to update the
+ * incore size so that inode inactivation won't punch what it
+ * thinks are "posteof" blocks.
+ */
+ mp->m_rsumip->i_disk_size = nmp->m_rsumsize;
+ i_size_write(VFS_I(mp->m_rsumip), mp->m_rsumip->i_disk_size);
+ xfs_trans_log_inode(tp, mp->m_rsumip, XFS_ILOG_CORE);
+ /*
+ * Copy summary data from old to new sizes.
+ * Do this when the real size (not block-aligned) changes.
+ */
+ if (sbp->sb_rbmblocks != nsbp->sb_rbmblocks ||
+ mp->m_rsumlevels != nmp->m_rsumlevels) {
+ error = xfs_rtcopy_summary(mp, nmp, tp);
+ if (error)
+ goto error_cancel;
+ }
+ /*
+ * Update superblock fields.
+ */
+ if (nsbp->sb_rextsize != sbp->sb_rextsize)
+ xfs_trans_mod_sb(tp, XFS_TRANS_SB_REXTSIZE,
+ nsbp->sb_rextsize - sbp->sb_rextsize);
+ if (nsbp->sb_rbmblocks != sbp->sb_rbmblocks)
+ xfs_trans_mod_sb(tp, XFS_TRANS_SB_RBMBLOCKS,
+ nsbp->sb_rbmblocks - sbp->sb_rbmblocks);
+ if (nsbp->sb_rblocks != sbp->sb_rblocks)
+ xfs_trans_mod_sb(tp, XFS_TRANS_SB_RBLOCKS,
+ nsbp->sb_rblocks - sbp->sb_rblocks);
+ if (nsbp->sb_rextents != sbp->sb_rextents)
+ xfs_trans_mod_sb(tp, XFS_TRANS_SB_REXTENTS,
+ nsbp->sb_rextents - sbp->sb_rextents);
+ if (nsbp->sb_rextslog != sbp->sb_rextslog)
+ xfs_trans_mod_sb(tp, XFS_TRANS_SB_REXTSLOG,
+ nsbp->sb_rextslog - sbp->sb_rextslog);
+ /*
+ * Free new extent.
+ */
+ bp = NULL;
+ error = xfs_rtfree_range(nmp, tp, sbp->sb_rextents,
+ nsbp->sb_rextents - sbp->sb_rextents, &bp, &sumbno);
+ if (error) {
+error_cancel:
+ xfs_trans_cancel(tp);
+ break;
+ }
+ /*
+ * Mark more blocks free in the superblock.
+ */
+ xfs_trans_mod_sb(tp, XFS_TRANS_SB_FREXTENTS,
+ nsbp->sb_rextents - sbp->sb_rextents);
+ /*
+ * Update mp values into the real mp structure.
+ */
+ mp->m_rsumlevels = nrsumlevels;
+ mp->m_rsumsize = nrsumsize;
+
+ error = xfs_trans_commit(tp);
+ if (error)
+ break;
+
+ /* Ensure the mount RT feature flag is now set. */
+ mp->m_features |= XFS_FEAT_REALTIME;
+ }
+ if (error)
+ goto out_free;
+
+ /* Update secondary superblocks now the physical grow has completed */
+ error = xfs_update_secondary_sbs(mp);
+
+out_free:
+ /*
+ * Free the fake mp structure.
+ */
+ kmem_free(nmp);
+
+ /*
+ * If we had to allocate a new rsum_cache, we either need to free the
+ * old one (if we succeeded) or free the new one and restore the old one
+ * (if there was an error).
+ */
+ if (rsum_cache != mp->m_rsum_cache) {
+ if (error) {
+ kmem_free(mp->m_rsum_cache);
+ mp->m_rsum_cache = rsum_cache;
+ } else {
+ kmem_free(rsum_cache);
+ }
+ }
+
+ return error;
+}
+
+/*
+ * Allocate an extent in the realtime subvolume, with the usual allocation
+ * parameters. The length units are all in realtime extents, as is the
+ * result block number.
+ */
+int /* error */
+xfs_rtallocate_extent(
+ xfs_trans_t *tp, /* transaction pointer */
+ xfs_rtblock_t bno, /* starting block number to allocate */
+ xfs_extlen_t minlen, /* minimum length to allocate */
+ xfs_extlen_t maxlen, /* maximum length to allocate */
+ xfs_extlen_t *len, /* out: actual length allocated */
+ int wasdel, /* was a delayed allocation extent */
+ xfs_extlen_t prod, /* extent product factor */
+ xfs_rtblock_t *rtblock) /* out: start block allocated */
+{
+ xfs_mount_t *mp = tp->t_mountp;
+ int error; /* error value */
+ xfs_rtblock_t r; /* result allocated block */
+ xfs_fsblock_t sb; /* summary file block number */
+ struct xfs_buf *sumbp; /* summary file block buffer */
+
+ ASSERT(xfs_isilocked(mp->m_rbmip, XFS_ILOCK_EXCL));
+ ASSERT(minlen > 0 && minlen <= maxlen);
+
+ /*
+ * If prod is set then figure out what to do to minlen and maxlen.
+ */
+ if (prod > 1) {
+ xfs_extlen_t i;
+
+ if ((i = maxlen % prod))
+ maxlen -= i;
+ if ((i = minlen % prod))
+ minlen += prod - i;
+ if (maxlen < minlen) {
+ *rtblock = NULLRTBLOCK;
+ return 0;
+ }
+ }
+
+retry:
+ sumbp = NULL;
+ if (bno == 0) {
+ error = xfs_rtallocate_extent_size(mp, tp, minlen, maxlen, len,
+ &sumbp, &sb, prod, &r);
+ } else {
+ error = xfs_rtallocate_extent_near(mp, tp, bno, minlen, maxlen,
+ len, &sumbp, &sb, prod, &r);
+ }
+
+ if (error)
+ return error;
+
+ /*
+ * If it worked, update the superblock.
+ */
+ if (r != NULLRTBLOCK) {
+ long slen = (long)*len;
+
+ ASSERT(*len >= minlen && *len <= maxlen);
+ if (wasdel)
+ xfs_trans_mod_sb(tp, XFS_TRANS_SB_RES_FREXTENTS, -slen);
+ else
+ xfs_trans_mod_sb(tp, XFS_TRANS_SB_FREXTENTS, -slen);
+ } else if (prod > 1) {
+ prod = 1;
+ goto retry;
+ }
+
+ *rtblock = r;
+ return 0;
+}
+
+/*
+ * Initialize realtime fields in the mount structure.
+ */
+int /* error */
+xfs_rtmount_init(
+ struct xfs_mount *mp) /* file system mount structure */
+{
+ struct xfs_buf *bp; /* buffer for last block of subvolume */
+ struct xfs_sb *sbp; /* filesystem superblock copy in mount */
+ xfs_daddr_t d; /* address of last block of subvolume */
+ int error;
+
+ sbp = &mp->m_sb;
+ if (sbp->sb_rblocks == 0)
+ return 0;
+ if (mp->m_rtdev_targp == NULL) {
+ xfs_warn(mp,
+ "Filesystem has a realtime volume, use rtdev=device option");
+ return -ENODEV;
+ }
+ mp->m_rsumlevels = sbp->sb_rextslog + 1;
+ mp->m_rsumsize =
+ (uint)sizeof(xfs_suminfo_t) * mp->m_rsumlevels *
+ sbp->sb_rbmblocks;
+ mp->m_rsumsize = roundup(mp->m_rsumsize, sbp->sb_blocksize);
+ mp->m_rbmip = mp->m_rsumip = NULL;
+ /*
+ * Check that the realtime section is an ok size.
+ */
+ d = (xfs_daddr_t)XFS_FSB_TO_BB(mp, mp->m_sb.sb_rblocks);
+ if (XFS_BB_TO_FSB(mp, d) != mp->m_sb.sb_rblocks) {
+ xfs_warn(mp, "realtime mount -- %llu != %llu",
+ (unsigned long long) XFS_BB_TO_FSB(mp, d),
+ (unsigned long long) mp->m_sb.sb_rblocks);
+ return -EFBIG;
+ }
+ error = xfs_buf_read_uncached(mp->m_rtdev_targp,
+ d - XFS_FSB_TO_BB(mp, 1),
+ XFS_FSB_TO_BB(mp, 1), 0, &bp, NULL);
+ if (error) {
+ xfs_warn(mp, "realtime device size check failed");
+ return error;
+ }
+ xfs_buf_relse(bp);
+ return 0;
+}
+
+static int
+xfs_rtalloc_count_frextent(
+ struct xfs_mount *mp,
+ struct xfs_trans *tp,
+ const struct xfs_rtalloc_rec *rec,
+ void *priv)
+{
+ uint64_t *valp = priv;
+
+ *valp += rec->ar_extcount;
+ return 0;
+}
+
+/*
+ * Reinitialize the number of free realtime extents from the realtime bitmap.
+ * Callers must ensure that there is no other activity in the filesystem.
+ */
+int
+xfs_rtalloc_reinit_frextents(
+ struct xfs_mount *mp)
+{
+ uint64_t val = 0;
+ int error;
+
+ xfs_ilock(mp->m_rbmip, XFS_ILOCK_EXCL);
+ error = xfs_rtalloc_query_all(mp, NULL, xfs_rtalloc_count_frextent,
+ &val);
+ xfs_iunlock(mp->m_rbmip, XFS_ILOCK_EXCL);
+ if (error)
+ return error;
+
+ spin_lock(&mp->m_sb_lock);
+ mp->m_sb.sb_frextents = val;
+ spin_unlock(&mp->m_sb_lock);
+ percpu_counter_set(&mp->m_frextents, mp->m_sb.sb_frextents);
+ return 0;
+}
+
+/*
+ * Get the bitmap and summary inodes and the summary cache into the mount
+ * structure at mount time.
+ */
+int /* error */
+xfs_rtmount_inodes(
+ xfs_mount_t *mp) /* file system mount structure */
+{
+ int error; /* error return value */
+ xfs_sb_t *sbp;
+
+ sbp = &mp->m_sb;
+ error = xfs_iget(mp, NULL, sbp->sb_rbmino, 0, 0, &mp->m_rbmip);
+ if (error)
+ return error;
+ ASSERT(mp->m_rbmip != NULL);
+
+ error = xfs_iget(mp, NULL, sbp->sb_rsumino, 0, 0, &mp->m_rsumip);
+ if (error) {
+ xfs_irele(mp->m_rbmip);
+ return error;
+ }
+ ASSERT(mp->m_rsumip != NULL);
+ xfs_alloc_rsum_cache(mp, sbp->sb_rbmblocks);
+ return 0;
+}
+
+void
+xfs_rtunmount_inodes(
+ struct xfs_mount *mp)
+{
+ kmem_free(mp->m_rsum_cache);
+ if (mp->m_rbmip)
+ xfs_irele(mp->m_rbmip);
+ if (mp->m_rsumip)
+ xfs_irele(mp->m_rsumip);
+}
+
+/*
+ * Pick an extent for allocation at the start of a new realtime file.
+ * Use the sequence number stored in the atime field of the bitmap inode.
+ * Translate this to a fraction of the rtextents, and return the product
+ * of rtextents and the fraction.
+ * The fraction sequence is 0, 1/2, 1/4, 3/4, 1/8, ..., 7/8, 1/16, ...
+ */
+int /* error */
+xfs_rtpick_extent(
+ xfs_mount_t *mp, /* file system mount point */
+ xfs_trans_t *tp, /* transaction pointer */
+ xfs_extlen_t len, /* allocation length (rtextents) */
+ xfs_rtblock_t *pick) /* result rt extent */
+{
+ xfs_rtblock_t b; /* result block */
+ int log2; /* log of sequence number */
+ uint64_t resid; /* residual after log removed */
+ uint64_t seq; /* sequence number of file creation */
+ uint64_t *seqp; /* pointer to seqno in inode */
+
+ ASSERT(xfs_isilocked(mp->m_rbmip, XFS_ILOCK_EXCL));
+
+ seqp = (uint64_t *)&VFS_I(mp->m_rbmip)->i_atime;
+ if (!(mp->m_rbmip->i_diflags & XFS_DIFLAG_NEWRTBM)) {
+ mp->m_rbmip->i_diflags |= XFS_DIFLAG_NEWRTBM;
+ *seqp = 0;
+ }
+ seq = *seqp;
+ if ((log2 = xfs_highbit64(seq)) == -1)
+ b = 0;
+ else {
+ resid = seq - (1ULL << log2);
+ b = (mp->m_sb.sb_rextents * ((resid << 1) + 1ULL)) >>
+ (log2 + 1);
+ if (b >= mp->m_sb.sb_rextents)
+ div64_u64_rem(b, mp->m_sb.sb_rextents, &b);
+ if (b + len > mp->m_sb.sb_rextents)
+ b = mp->m_sb.sb_rextents - len;
+ }
+ *seqp = seq + 1;
+ xfs_trans_log_inode(tp, mp->m_rbmip, XFS_ILOG_CORE);
+ *pick = b;
+ return 0;
+}