From 5419040fc0f3afc31c857b4d7f006bd9afbdb462 Mon Sep 17 00:00:00 2001 From: Brian Foster Date: Fri, 29 May 2015 09:03:04 +1000 Subject: xfs: introduce inode record hole mask for sparse inode chunks The inode btrees track 64 inodes per record regardless of inode size. Thus, inode chunks on disk vary in size depending on the size of the inodes. This creates a contiguous allocation requirement for new inode chunks that can be difficult to satisfy on an aged and fragmented (free space) filesystems. The inode record freecount currently uses 4 bytes on disk to track the free inode count. With a maximum freecount value of 64, only one byte is required. Convert the freecount field to a single byte and use two of the remaining 3 higher order bytes left for the hole mask field. Use the final leftover byte for the total count field. The hole mask field tracks holes in the chunks of physical space that the inode record refers to. This facilitates the sparse allocation of inode chunks when contiguous chunks are not available and allows the inode btrees to identify what portions of the chunk contain valid inodes. The total count field contains the total number of valid inodes referred to by the record. This can also be deduced from the hole mask. The count field provides clarity and redundancy for internal record verification. Note that neither of the new fields can be written to disk on fs' without sparse inode support. Doing so writes to the high-order bytes of freecount and causes corruption from the perspective of older kernels. The on-disk inobt record data structure is updated with a union to distinguish between the original, "full" format and the new, "sparse" format. The conversion routines to get, insert and update records are updated to translate to and from the on-disk record accordingly such that freecount remains a 4-byte value on non-supported fs, yet the new fields of the in-core record are always valid with respect to the record. This means that higher level code can refer to the current in-core record format unconditionally and lower level code ensures that records are translated to/from disk according to the capabilities of the fs. Signed-off-by: Brian Foster Reviewed-by: Dave Chinner Signed-off-by: Dave Chinner --- fs/xfs/libxfs/xfs_ialloc_btree.c | 11 ++++++++++- 1 file changed, 10 insertions(+), 1 deletion(-) (limited to 'fs/xfs/libxfs/xfs_ialloc_btree.c') diff --git a/fs/xfs/libxfs/xfs_ialloc_btree.c b/fs/xfs/libxfs/xfs_ialloc_btree.c index 964c465ca69c..b95aac5b5a81 100644 --- a/fs/xfs/libxfs/xfs_ialloc_btree.c +++ b/fs/xfs/libxfs/xfs_ialloc_btree.c @@ -167,7 +167,16 @@ xfs_inobt_init_rec_from_cur( union xfs_btree_rec *rec) { rec->inobt.ir_startino = cpu_to_be32(cur->bc_rec.i.ir_startino); - rec->inobt.ir_freecount = cpu_to_be32(cur->bc_rec.i.ir_freecount); + if (xfs_sb_version_hassparseinodes(&cur->bc_mp->m_sb)) { + rec->inobt.ir_u.sp.ir_holemask = + cpu_to_be16(cur->bc_rec.i.ir_holemask); + rec->inobt.ir_u.sp.ir_count = cur->bc_rec.i.ir_count; + rec->inobt.ir_u.sp.ir_freecount = cur->bc_rec.i.ir_freecount; + } else { + /* ir_holemask/ir_count not supported on-disk */ + rec->inobt.ir_u.f.ir_freecount = + cpu_to_be32(cur->bc_rec.i.ir_freecount); + } rec->inobt.ir_free = cpu_to_be64(cur->bc_rec.i.ir_free); } -- cgit v1.2.3 From 4148c347a42a2aba31f6f4d9a31c647c2d475697 Mon Sep 17 00:00:00 2001 From: Brian Foster Date: Fri, 29 May 2015 09:09:05 +1000 Subject: xfs: helper to convert holemask to inode alloc. bitmap The inobt record holemask field is a condensed data type designed to fit into the existing on-disk record and is zero based (allocated regions are set to 0, sparse regions are set to 1) to provide backwards compatibility. This makes the type somewhat complex for use in higher level inode manipulations such as individual inode allocation, etc. Rather than foist the complexity of dealing with this field to every bit of logic that requires inode granular information, create a helper to convert the holemask to an inode allocation bitmap. The inode allocation bitmap is inode granularity similar to the inobt record free mask and indicates which inodes of the chunk are physically allocated on disk, irrespective of whether the inode is considered allocated or free by the filesystem. Signed-off-by: Brian Foster Reviewed-by: Dave Chinner Signed-off-by: Dave Chinner --- fs/xfs/libxfs/xfs_ialloc_btree.c | 51 ++++++++++++++++++++++++++++++++++++++++ 1 file changed, 51 insertions(+) (limited to 'fs/xfs/libxfs/xfs_ialloc_btree.c') diff --git a/fs/xfs/libxfs/xfs_ialloc_btree.c b/fs/xfs/libxfs/xfs_ialloc_btree.c index b95aac5b5a81..aa13b468a064 100644 --- a/fs/xfs/libxfs/xfs_ialloc_btree.c +++ b/fs/xfs/libxfs/xfs_ialloc_btree.c @@ -427,3 +427,54 @@ xfs_inobt_maxrecs( return blocklen / sizeof(xfs_inobt_rec_t); return blocklen / (sizeof(xfs_inobt_key_t) + sizeof(xfs_inobt_ptr_t)); } + +/* + * Convert the inode record holemask to an inode allocation bitmap. The inode + * allocation bitmap is inode granularity and specifies whether an inode is + * physically allocated on disk (not whether the inode is considered allocated + * or free by the fs). + * + * A bit value of 1 means the inode is allocated, a value of 0 means it is free. + */ +uint64_t +xfs_inobt_irec_to_allocmask( + struct xfs_inobt_rec_incore *rec) +{ + uint64_t bitmap = 0; + uint64_t inodespbit; + int nextbit; + uint allocbitmap; + + /* + * The holemask has 16-bits for a 64 inode record. Therefore each + * holemask bit represents multiple inodes. Create a mask of bits to set + * in the allocmask for each holemask bit. + */ + inodespbit = (1 << XFS_INODES_PER_HOLEMASK_BIT) - 1; + + /* + * Allocated inodes are represented by 0 bits in holemask. Invert the 0 + * bits to 1 and convert to a uint so we can use xfs_next_bit(). Mask + * anything beyond the 16 holemask bits since this casts to a larger + * type. + */ + allocbitmap = ~rec->ir_holemask & ((1 << XFS_INOBT_HOLEMASK_BITS) - 1); + + /* + * allocbitmap is the inverted holemask so every set bit represents + * allocated inodes. To expand from 16-bit holemask granularity to + * 64-bit (e.g., bit-per-inode), set inodespbit bits in the target + * bitmap for every holemask bit. + */ + nextbit = xfs_next_bit(&allocbitmap, 1, 0); + while (nextbit != -1) { + ASSERT(nextbit < (sizeof(rec->ir_holemask) * NBBY)); + + bitmap |= (inodespbit << + (nextbit * XFS_INODES_PER_HOLEMASK_BIT)); + + nextbit = xfs_next_bit(&allocbitmap, 1, nextbit + 1); + } + + return bitmap; +} -- cgit v1.2.3 From 56d1115c9bc7853e143f59fb5976cf3de609f657 Mon Sep 17 00:00:00 2001 From: Brian Foster Date: Fri, 29 May 2015 09:18:32 +1000 Subject: xfs: allocate sparse inode chunks on full chunk allocation failure xfs_ialloc_ag_alloc() makes several attempts to allocate a full inode chunk. If all else fails, reduce the allocation to the sparse length and alignment and attempt to allocate a sparse inode chunk. If sparse chunk allocation succeeds, check whether an inobt record already exists that can track the chunk. If so, inherit and update the existing record. Otherwise, insert a new record for the sparse chunk. Create helpers to align sparse chunk inode records and insert or update existing records in the inode btrees. The xfs_inobt_insert_sprec() helper implements the merge or update semantics required for sparse inode records with respect to both the inobt and finobt. To update the inobt, either insert a new record or merge with an existing record. To update the finobt, use the updated inobt record to either insert or replace an existing record. Signed-off-by: Brian Foster Reviewed-by: Dave Chinner Signed-off-by: Dave Chinner --- fs/xfs/libxfs/xfs_ialloc_btree.c | 31 +++++++++++++++++++++++++++++++ 1 file changed, 31 insertions(+) (limited to 'fs/xfs/libxfs/xfs_ialloc_btree.c') diff --git a/fs/xfs/libxfs/xfs_ialloc_btree.c b/fs/xfs/libxfs/xfs_ialloc_btree.c index aa13b468a064..674ad8f760be 100644 --- a/fs/xfs/libxfs/xfs_ialloc_btree.c +++ b/fs/xfs/libxfs/xfs_ialloc_btree.c @@ -478,3 +478,34 @@ xfs_inobt_irec_to_allocmask( return bitmap; } + +#if defined(DEBUG) || defined(XFS_WARN) +/* + * Verify that an in-core inode record has a valid inode count. + */ +int +xfs_inobt_rec_check_count( + struct xfs_mount *mp, + struct xfs_inobt_rec_incore *rec) +{ + int inocount = 0; + int nextbit = 0; + uint64_t allocbmap; + int wordsz; + + wordsz = sizeof(allocbmap) / sizeof(unsigned int); + allocbmap = xfs_inobt_irec_to_allocmask(rec); + + nextbit = xfs_next_bit((uint *) &allocbmap, wordsz, nextbit); + while (nextbit != -1) { + inocount++; + nextbit = xfs_next_bit((uint *) &allocbmap, wordsz, + nextbit + 1); + } + + if (inocount != rec->ir_count) + return -EFSCORRUPTED; + + return 0; +} +#endif /* DEBUG */ -- cgit v1.2.3