svn commit: r293680 - head/sys/fs/ext2fs
Pedro F. Giffuni
pfg at FreeBSD.org
Mon Jan 11 19:14:57 UTC 2016
Author: pfg
Date: Mon Jan 11 19:14:55 2016
New Revision: 293680
URL: https://svnweb.freebsd.org/changeset/base/293680
Log:
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
Modified:
head/sys/fs/ext2fs/ext2_bmap.c
head/sys/fs/ext2fs/ext2_extents.c
head/sys/fs/ext2fs/ext2_extents.h
head/sys/fs/ext2fs/ext2_vnops.c
Modified: head/sys/fs/ext2fs/ext2_bmap.c
==============================================================================
--- head/sys/fs/ext2fs/ext2_bmap.c Mon Jan 11 18:11:06 2016 (r293679)
+++ head/sys/fs/ext2fs/ext2_bmap.c Mon Jan 11 19:14:55 2016 (r293680)
@@ -102,9 +102,6 @@ ext4_bmapext(struct vnode *vp, int32_t b
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 b
*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) {
Modified: head/sys/fs/ext2fs/ext2_extents.c
==============================================================================
--- head/sys/fs/ext2fs/ext2_extents.c Mon Jan 11 18:11:06 2016 (r293679)
+++ head/sys/fs/ext2fs/ext2_extents.c Mon Jan 11 19:14:55 2016 (r293680)
@@ -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, str
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
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);
Modified: head/sys/fs/ext2fs/ext2_extents.h
==============================================================================
--- head/sys/fs/ext2fs/ext2_extents.h Mon Jan 11 18:11:06 2016 (r293679)
+++ head/sys/fs/ext2fs/ext2_extents.h Mon Jan 11 19:14:55 2016 (r293680)
@@ -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;
};
Modified: head/sys/fs/ext2fs/ext2_vnops.c
==============================================================================
--- head/sys/fs/ext2fs/ext2_vnops.c Mon Jan 11 18:11:06 2016 (r293679)
+++ head/sys/fs/ext2fs/ext2_vnops.c Mon Jan 11 19:14:55 2016 (r293680)
@@ -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);
- }
+ 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);
+ }
- size -= bp->b_resid;
- if (size < xfersize) {
- if (size == 0) {
- bqrelse(bp);
- break;
+ size -= bp->b_resid;
+ if (size < xfersize) {
+ if (size == 0) {
+ bqrelse(bp);
+ break;
+ }
+ xfersize = size;
}
- 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);
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