From 52388dd9b7708ba89d74861bbc50bda8bd38307c Mon Sep 17 00:00:00 2001 From: pfg Date: Mon, 11 Jan 2016 19:14:55 +0000 Subject: [PATCH] ext4: add support for reading sparse files Add support for sparse files in ext4. Also implement read-ahead, which greatly increases the performance when transferring files from ext4. Both features implemented by Damjan Jovanovic. PR: 205816 MFC after: 1 week --- sys/fs/ext2fs/ext2_bmap.c | 29 ++++++++++++-------- sys/fs/ext2fs/ext2_extents.c | 26 ++++++++++++++++-- sys/fs/ext2fs/ext2_extents.h | 6 +++- sys/fs/ext2fs/ext2_vnops.c | 53 +++++++++++++++++++++++------------- 4 files changed, 80 insertions(+), 34 deletions(-) diff --git a/sys/fs/ext2fs/ext2_bmap.c b/sys/fs/ext2fs/ext2_bmap.c index 7d4a88007a81..8656e59ed8f0 100644 --- a/sys/fs/ext2fs/ext2_bmap.c +++ b/sys/fs/ext2fs/ext2_bmap.c @@ -102,9 +102,6 @@ ext4_bmapext(struct vnode *vp, int32_t bn, int64_t *bnp, int *runp, int *runb) fs = ip->i_e2fs; lbn = bn; - /* - * TODO: need to implement read ahead to improve the performance. - */ if (runp != NULL) *runp = 0; @@ -112,15 +109,25 @@ ext4_bmapext(struct vnode *vp, int32_t bn, int64_t *bnp, int *runp, int *runb) *runb = 0; ext4_ext_find_extent(fs, ip, lbn, &path); - ep = path.ep_ext; - if (ep == NULL) - ret = EIO; - else { - *bnp = fsbtodb(fs, lbn - ep->e_blk + - (ep->e_start_lo | (daddr_t)ep->e_start_hi << 32)); + if (path.ep_is_sparse) { + *bnp = -1; + if (runp != NULL) + *runp = path.ep_sparse_ext.e_len - + (lbn - path.ep_sparse_ext.e_blk) - 1; + } else { + ep = path.ep_ext; + if (ep == NULL) + ret = EIO; + else { + *bnp = fsbtodb(fs, lbn - ep->e_blk + + (ep->e_start_lo | (daddr_t)ep->e_start_hi << 32)); - if (*bnp == 0) - *bnp = -1; + if (*bnp == 0) + *bnp = -1; + + if (runp != NULL) + *runp = ep->e_len - (lbn - ep->e_blk) - 1; + } } if (path.ep_bp != NULL) { diff --git a/sys/fs/ext2fs/ext2_extents.c b/sys/fs/ext2fs/ext2_extents.c index 68704bb88504..1317fdcca2c4 100644 --- a/sys/fs/ext2fs/ext2_extents.c +++ b/sys/fs/ext2fs/ext2_extents.c @@ -66,13 +66,14 @@ static void ext4_ext_binsearch(struct inode *ip, struct ext4_extent_path *path, daddr_t lbn) { struct ext4_extent_header *ehp = path->ep_header; - struct ext4_extent *l, *r, *m; + struct ext4_extent *first, *l, *r, *m; if (ehp->eh_ecount == 0) return; - l = (struct ext4_extent *)(char *)(ehp + 1); - r = (struct ext4_extent *)(char *)(ehp + 1) + ehp->eh_ecount - 1; + first = (struct ext4_extent *)(char *)(ehp + 1); + l = first; + r = first + ehp->eh_ecount - 1; while (l <= r) { m = l + (r - l) / 2; if (lbn < m->e_blk) @@ -81,7 +82,25 @@ ext4_ext_binsearch(struct inode *ip, struct ext4_extent_path *path, daddr_t lbn) l = m + 1; } + if (l == first) { + path->ep_sparse_ext.e_blk = lbn; + path->ep_sparse_ext.e_len = first->e_blk - lbn; + path->ep_sparse_ext.e_start_hi = 0; + path->ep_sparse_ext.e_start_lo = 0; + path->ep_is_sparse = 1; + return; + } path->ep_ext = l - 1; + if (path->ep_ext->e_blk + path->ep_ext->e_len <= lbn) { + path->ep_sparse_ext.e_blk = lbn; + if (l <= (first + ehp->eh_ecount - 1)) + path->ep_sparse_ext.e_len = l->e_blk - lbn; + else // XXX: where does it end? + path->ep_sparse_ext.e_len = 1; + path->ep_sparse_ext.e_start_hi = 0; + path->ep_sparse_ext.e_start_lo = 0; + path->ep_is_sparse = 1; + } } /* @@ -169,6 +188,7 @@ ext4_ext_find_extent(struct m_ext2fs *fs, struct inode *ip, path->ep_depth = i; path->ep_ext = NULL; path->ep_index = NULL; + path->ep_is_sparse = 0; ext4_ext_binsearch(ip, path, lbn); return (path); diff --git a/sys/fs/ext2fs/ext2_extents.h b/sys/fs/ext2fs/ext2_extents.h index 94ded83b1eb8..4ce16f3e69ba 100644 --- a/sys/fs/ext2fs/ext2_extents.h +++ b/sys/fs/ext2fs/ext2_extents.h @@ -84,7 +84,11 @@ struct ext4_extent_cache { struct ext4_extent_path { uint16_t ep_depth; struct buf *ep_bp; - struct ext4_extent *ep_ext; + int ep_is_sparse; + union { + struct ext4_extent ep_sparse_ext; + struct ext4_extent *ep_ext; + }; struct ext4_extent_index *ep_index; struct ext4_extent_header *ep_header; }; diff --git a/sys/fs/ext2fs/ext2_vnops.c b/sys/fs/ext2fs/ext2_vnops.c index 5b8990ee84c4..bc239b8f1630 100644 --- a/sys/fs/ext2fs/ext2_vnops.c +++ b/sys/fs/ext2fs/ext2_vnops.c @@ -1787,6 +1787,7 @@ ext2_ioctl(struct vop_ioctl_args *ap) static int ext4_ext_read(struct vop_read_args *ap) { + static unsigned char zeroes[EXT2_MAX_BLOCK_SIZE]; struct vnode *vp; struct inode *ip; struct uio *uio; @@ -1831,11 +1832,15 @@ ext4_ext_read(struct vop_read_args *ap) switch (cache_type) { case EXT4_EXT_CACHE_NO: ext4_ext_find_extent(fs, ip, lbn, &path); - ep = path.ep_ext; + if (path.ep_is_sparse) + ep = &path.ep_sparse_ext; + else + ep = path.ep_ext; if (ep == NULL) return (EIO); - ext4_ext_put_cache(ip, ep, EXT4_EXT_CACHE_IN); + ext4_ext_put_cache(ip, ep, + path.ep_is_sparse ? EXT4_EXT_CACHE_GAP : EXT4_EXT_CACHE_IN); newblk = lbn - ep->e_blk + (ep->e_start_lo | (daddr_t)ep->e_start_hi << 32); @@ -1848,7 +1853,7 @@ ext4_ext_read(struct vop_read_args *ap) case EXT4_EXT_CACHE_GAP: /* block has not been allocated yet */ - return (0); + break; case EXT4_EXT_CACHE_IN: newblk = lbn - nex.e_blk + (nex.e_start_lo | @@ -1859,24 +1864,34 @@ ext4_ext_read(struct vop_read_args *ap) panic("%s: invalid cache type", __func__); } - error = bread(ip->i_devvp, fsbtodb(fs, newblk), size, NOCRED, &bp); - if (error) { - brelse(bp); - return (error); - } - - size -= bp->b_resid; - if (size < xfersize) { - if (size == 0) { - bqrelse(bp); - break; + if (cache_type == EXT4_EXT_CACHE_GAP || + (cache_type == EXT4_EXT_CACHE_NO && path.ep_is_sparse)) { + if (xfersize > sizeof(zeroes)) + xfersize = sizeof(zeroes); + error = uiomove(zeroes, xfersize, uio); + if (error) + return (error); + } else { + error = bread(ip->i_devvp, fsbtodb(fs, newblk), size, + NOCRED, &bp); + if (error) { + brelse(bp); + return (error); } - xfersize = size; + + size -= bp->b_resid; + if (size < xfersize) { + if (size == 0) { + bqrelse(bp); + break; + } + xfersize = size; + } + error = uiomove(bp->b_data + blkoffset, xfersize, uio); + bqrelse(bp); + if (error) + return (error); } - error = uiomove(bp->b_data + blkoffset, (int)xfersize, uio); - bqrelse(bp); - if (error) - return (error); } return (0);