diff options
| -rw-r--r-- | fs/xfs/libxfs/xfs_btree.c | 33 | ||||
| -rw-r--r-- | fs/xfs/libxfs/xfs_btree.h | 2 | ||||
| -rw-r--r-- | fs/xfs/libxfs/xfs_rmap_btree.c | 45 | ||||
| -rw-r--r-- | fs/xfs/libxfs/xfs_trans_resv.c | 16 | ||||
| -rw-r--r-- | fs/xfs/libxfs/xfs_trans_space.h | 7 |
5 files changed, 85 insertions, 18 deletions
diff --git a/fs/xfs/libxfs/xfs_btree.c b/fs/xfs/libxfs/xfs_btree.c index 4d95a3bb05cd..43e646f3956c 100644 --- a/fs/xfs/libxfs/xfs_btree.c +++ b/fs/xfs/libxfs/xfs_btree.c @@ -4554,6 +4554,39 @@ xfs_btree_calc_size( } /* + * Given a number of available blocks for the btree to consume with records and + * pointers, calculate the height of the tree needed to index all the records + * that space can hold based on the number of pointers each interior node + * holds. + * + * We start by assuming a single level tree consumes a single block, then track + * the number of blocks each node level consumes until we no longer have space + * to store the next node level. At this point, we are indexing all the leaf + * blocks in the space, and there's no more free space to split the tree any + * further. That's our maximum btree height. + */ +unsigned int +xfs_btree_space_to_height( + const unsigned int *limits, + unsigned long long leaf_blocks) +{ + unsigned long long node_blocks = limits[1]; + unsigned long long blocks_left = leaf_blocks - 1; + unsigned int height = 1; + + if (leaf_blocks < 1) + return 0; + + while (node_blocks < blocks_left) { + blocks_left -= node_blocks; + node_blocks *= limits[1]; + height++; + } + + return height; +} + +/* * Query a regular btree for all records overlapping a given interval. * Start with a LE lookup of the key of low_rec and return all records * until we find a record with a key greater than the key of high_rec. diff --git a/fs/xfs/libxfs/xfs_btree.h b/fs/xfs/libxfs/xfs_btree.h index 3bd69fe425a7..e488bfcc1fc0 100644 --- a/fs/xfs/libxfs/xfs_btree.h +++ b/fs/xfs/libxfs/xfs_btree.h @@ -491,6 +491,8 @@ unsigned int xfs_btree_compute_maxlevels(const unsigned int *limits, unsigned long long records); unsigned long long xfs_btree_calc_size(const unsigned int *limits, unsigned long long records); +unsigned int xfs_btree_space_to_height(const unsigned int *limits, + unsigned long long blocks); /* * Return codes for the query range iterator function are 0 to continue diff --git a/fs/xfs/libxfs/xfs_rmap_btree.c b/fs/xfs/libxfs/xfs_rmap_btree.c index 1b48b7b3ee30..7388201e48d2 100644 --- a/fs/xfs/libxfs/xfs_rmap_btree.c +++ b/fs/xfs/libxfs/xfs_rmap_btree.c @@ -540,26 +540,35 @@ void xfs_rmapbt_compute_maxlevels( struct xfs_mount *mp) { - /* - * On a non-reflink filesystem, the maximum number of rmap - * records is the number of blocks in the AG, hence the max - * rmapbt height is log_$maxrecs($agblocks). However, with - * reflink each AG block can have up to 2^32 (per the refcount - * record format) owners, which means that theoretically we - * could face up to 2^64 rmap records. - * - * That effectively means that the max rmapbt height must be - * XFS_BTREE_MAXLEVELS. "Fortunately" we'll run out of AG - * blocks to feed the rmapbt long before the rmapbt reaches - * maximum height. The reflink code uses ag_resv_critical to - * disallow reflinking when less than 10% of the per-AG metadata - * block reservation since the fallback is a regular file copy. - */ - if (xfs_has_reflink(mp)) - mp->m_rmap_maxlevels = XFS_BTREE_MAXLEVELS; - else + if (!xfs_has_rmapbt(mp)) { + mp->m_rmap_maxlevels = 0; + return; + } + + if (xfs_has_reflink(mp)) { + /* + * Compute the asymptotic maxlevels for an rmap btree on a + * filesystem that supports reflink. + * + * On a reflink filesystem, each AG block can have up to 2^32 + * (per the refcount record format) owners, which means that + * theoretically we could face up to 2^64 rmap records. + * However, we're likely to run out of blocks in the AG long + * before that happens, which means that we must compute the + * max height based on what the btree will look like if it + * consumes almost all the blocks in the AG due to maximal + * sharing factor. + */ + mp->m_rmap_maxlevels = xfs_btree_space_to_height(mp->m_rmap_mnr, + mp->m_sb.sb_agblocks); + } else { + /* + * If there's no block sharing, compute the maximum rmapbt + * height assuming one rmap record per AG block. + */ mp->m_rmap_maxlevels = xfs_btree_compute_maxlevels( mp->m_rmap_mnr, mp->m_sb.sb_agblocks); + } } /* Calculate the refcount btree size for some records. */ diff --git a/fs/xfs/libxfs/xfs_trans_resv.c b/fs/xfs/libxfs/xfs_trans_resv.c index c879e7754ee6..6f83d9b306ee 100644 --- a/fs/xfs/libxfs/xfs_trans_resv.c +++ b/fs/xfs/libxfs/xfs_trans_resv.c @@ -814,6 +814,19 @@ xfs_trans_resv_calc( struct xfs_mount *mp, struct xfs_trans_resv *resp) { + unsigned int rmap_maxlevels = mp->m_rmap_maxlevels; + + /* + * In the early days of rmap+reflink, we always set the rmap maxlevels + * to 9 even if the AG was small enough that it would never grow to + * that height. Transaction reservation sizes influence the minimum + * log size calculation, which influences the size of the log that mkfs + * creates. Use the old value here to ensure that newly formatted + * small filesystems will mount on older kernels. + */ + if (xfs_has_rmapbt(mp) && xfs_has_reflink(mp)) + mp->m_rmap_maxlevels = XFS_OLD_REFLINK_RMAP_MAXLEVELS; + /* * The following transactions are logged in physical format and * require a permanent reservation on space. @@ -916,4 +929,7 @@ xfs_trans_resv_calc( resp->tr_clearagi.tr_logres = xfs_calc_clear_agi_bucket_reservation(mp); resp->tr_growrtzero.tr_logres = xfs_calc_growrtzero_reservation(mp); resp->tr_growrtfree.tr_logres = xfs_calc_growrtfree_reservation(mp); + + /* Put everything back the way it was. This goes at the end. */ + mp->m_rmap_maxlevels = rmap_maxlevels; } diff --git a/fs/xfs/libxfs/xfs_trans_space.h b/fs/xfs/libxfs/xfs_trans_space.h index bd04cb836419..87b31c69a773 100644 --- a/fs/xfs/libxfs/xfs_trans_space.h +++ b/fs/xfs/libxfs/xfs_trans_space.h @@ -17,6 +17,13 @@ /* Adding one rmap could split every level up to the top of the tree. */ #define XFS_RMAPADD_SPACE_RES(mp) ((mp)->m_rmap_maxlevels) +/* + * Note that we historically set m_rmap_maxlevels to 9 when reflink is enabled, + * so we must preserve this behavior to avoid changing the transaction space + * reservations and minimum log size calculations for existing filesystems. + */ +#define XFS_OLD_REFLINK_RMAP_MAXLEVELS 9 + /* Blocks we might need to add "b" rmaps to a tree. */ #define XFS_NRMAPADD_SPACE_RES(mp, b)\ (((b + XFS_MAX_CONTIG_RMAPS_PER_BLOCK(mp) - 1) / \ |