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author | 2019-10-13 17:10:35 -0700 | |
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committer | 2019-10-21 09:04:58 -0700 | |
commit | 0e26d5ca4a40211a4e2acd15a5cb229184c1f867 (patch) | |
tree | 8d075a3a52110be444f9c3a311432b2c0b09708c /fs/xfs/libxfs/xfs_alloc.c | |
parent | xfs: refactor and reuse best extent scanning logic (diff) | |
download | linux-0e26d5ca4a40211a4e2acd15a5cb229184c1f867.tar.gz linux-0e26d5ca4a40211a4e2acd15a5cb229184c1f867.tar.bz2 linux-0e26d5ca4a40211a4e2acd15a5cb229184c1f867.zip |
xfs: refactor near mode alloc bnobt scan into separate function
In preparation to enhance the near mode allocation bnobt scan algorithm, lift
it into a separate function. No functional changes.
Signed-off-by: Brian Foster <bfoster@redhat.com>
Reviewed-by: Darrick J. Wong <darrick.wong@oracle.com>
Signed-off-by: Darrick J. Wong <darrick.wong@oracle.com>
Diffstat (limited to 'fs/xfs/libxfs/xfs_alloc.c')
-rw-r--r-- | fs/xfs/libxfs/xfs_alloc.c | 128 |
1 files changed, 74 insertions, 54 deletions
diff --git a/fs/xfs/libxfs/xfs_alloc.c b/fs/xfs/libxfs/xfs_alloc.c index 63b42320c472..facff6cb27a5 100644 --- a/fs/xfs/libxfs/xfs_alloc.c +++ b/fs/xfs/libxfs/xfs_alloc.c @@ -1231,6 +1231,78 @@ xfs_alloc_walk_iter( } /* + * Search in the by-bno btree to the left and to the right simultaneously until + * in each case we find a large enough free extent or run into the edge of the + * tree. When we run into the edge of the tree, we deactivate that cursor. + */ +STATIC int +xfs_alloc_ag_vextent_bnobt( + struct xfs_alloc_arg *args, + struct xfs_alloc_cur *acur, + int *stat) +{ + struct xfs_btree_cur *fbcur = NULL; + int error; + int i; + bool fbinc; + + ASSERT(acur->len == 0); + ASSERT(args->type == XFS_ALLOCTYPE_NEAR_BNO); + + *stat = 0; + + error = xfs_alloc_lookup_le(acur->bnolt, args->agbno, 0, &i); + if (error) + return error; + error = xfs_alloc_lookup_ge(acur->bnogt, args->agbno, 0, &i); + if (error) + return error; + + /* + * Loop going left with the leftward cursor, right with the rightward + * cursor, until either both directions give up or we find an entry at + * least as big as minlen. + */ + while (xfs_alloc_cur_active(acur->bnolt) || + xfs_alloc_cur_active(acur->bnogt)) { + error = xfs_alloc_walk_iter(args, acur, acur->bnolt, false, + true, 1, &i); + if (error) + return error; + if (i == 1) { + trace_xfs_alloc_cur_left(args); + fbcur = acur->bnogt; + fbinc = true; + break; + } + + error = xfs_alloc_walk_iter(args, acur, acur->bnogt, true, true, + 1, &i); + if (error) + return error; + if (i == 1) { + trace_xfs_alloc_cur_right(args); + fbcur = acur->bnolt; + fbinc = false; + break; + } + } + + /* search the opposite direction for a better entry */ + if (fbcur) { + error = xfs_alloc_walk_iter(args, acur, fbcur, fbinc, true, -1, + &i); + if (error) + return error; + } + + if (acur->len) + *stat = 1; + + return 0; +} + +/* * Allocate a variable extent near bno in the allocation group agno. * Extent's length (returned in len) will be between minlen and maxlen, * and of the form k * prod + mod unless there's nothing that large. @@ -1241,12 +1313,10 @@ xfs_alloc_ag_vextent_near( struct xfs_alloc_arg *args) { struct xfs_alloc_cur acur = {}; - struct xfs_btree_cur *fbcur = NULL; int error; /* error code */ int i; /* result code, temporary */ xfs_agblock_t bno; xfs_extlen_t len; - bool fbinc = false; #ifdef DEBUG /* * Randomly don't execute the first algorithm. @@ -1348,63 +1418,13 @@ restart: } /* - * Second algorithm. - * Search in the by-bno tree to the left and to the right - * simultaneously, until in each case we find a space big enough, - * or run into the edge of the tree. When we run into the edge, - * we deallocate that cursor. - * If both searches succeed, we compare the two spaces and pick - * the better one. - * With alignment, it's possible for both to fail; the upper - * level algorithm that picks allocation groups for allocations - * is not supposed to do this. + * Second algorithm. Search the bnobt left and right. */ - error = xfs_alloc_lookup_le(acur.bnolt, args->agbno, 0, &i); - if (error) - goto out; - error = xfs_alloc_lookup_ge(acur.bnogt, args->agbno, 0, &i); + error = xfs_alloc_ag_vextent_bnobt(args, &acur, &i); if (error) goto out; /* - * Loop going left with the leftward cursor, right with the rightward - * cursor, until either both directions give up or we find an entry at - * least as big as minlen. - */ - do { - error = xfs_alloc_walk_iter(args, &acur, acur.bnolt, false, - true, 1, &i); - if (error) - goto out; - if (i == 1) { - trace_xfs_alloc_cur_left(args); - fbcur = acur.bnogt; - fbinc = true; - break; - } - - error = xfs_alloc_walk_iter(args, &acur, acur.bnogt, true, true, - 1, &i); - if (error) - goto out; - if (i == 1) { - trace_xfs_alloc_cur_right(args); - fbcur = acur.bnolt; - fbinc = false; - break; - } - } while (xfs_alloc_cur_active(acur.bnolt) || - xfs_alloc_cur_active(acur.bnogt)); - - /* search the opposite direction for a better entry */ - if (fbcur) { - error = xfs_alloc_walk_iter(args, &acur, fbcur, fbinc, true, -1, - &i); - if (error) - goto out; - } - - /* * If we couldn't get anything, give up. */ if (!acur.len) { |