svn commit: r358073 - head/sys/fs/ext2fs

Fedor Uporov fsu at FreeBSD.org
Tue Feb 18 16:39:58 UTC 2020


Author: fsu
Date: Tue Feb 18 16:39:57 2020
New Revision: 358073
URL: https://svnweb.freebsd.org/changeset/base/358073

Log:
  Add a EXT2FS-specific implementation for lseek(SEEK_DATA).
  
  The lseek(SEEK_DATA) optimization logic could be simply borrowed from ufs side.
  See, https://reviews.freebsd.org/D19599.
  
  Reviewed by:    pfg
  MFC after:      1 week
  
  Differential Revision:    https://reviews.freebsd.org/D23605

Modified:
  head/sys/fs/ext2fs/ext2_bmap.c
  head/sys/fs/ext2fs/ext2_extern.h
  head/sys/fs/ext2fs/ext2_vnops.c

Modified: head/sys/fs/ext2fs/ext2_bmap.c
==============================================================================
--- head/sys/fs/ext2fs/ext2_bmap.c	Tue Feb 18 16:37:48 2020	(r358072)
+++ head/sys/fs/ext2fs/ext2_bmap.c	Tue Feb 18 16:39:57 2020	(r358073)
@@ -139,6 +139,47 @@ ext4_bmapext(struct vnode *vp, int32_t bn, int64_t *bn
 	return (error);
 }
 
+static int
+readindir(struct vnode *vp, e2fs_lbn_t lbn, e2fs_daddr_t daddr, struct buf **bpp)
+{
+	struct buf *bp;
+	struct mount *mp;
+	struct ext2mount *ump;
+	int error;
+
+	mp = vp->v_mount;
+	ump = VFSTOEXT2(mp);
+
+	bp = getblk(vp, lbn, mp->mnt_stat.f_iosize, 0, 0, 0);
+	if ((bp->b_flags & B_CACHE) == 0) {
+		KASSERT(daddr != 0,
+		    ("readindir: indirect block not in cache"));
+
+		bp->b_blkno = blkptrtodb(ump, daddr);
+		bp->b_iocmd = BIO_READ;
+		bp->b_flags &= ~B_INVAL;
+		bp->b_ioflags &= ~BIO_ERROR;
+		vfs_busy_pages(bp, 0);
+		bp->b_iooffset = dbtob(bp->b_blkno);
+		bstrategy(bp);
+#ifdef RACCT
+		if (racct_enable) {
+			PROC_LOCK(curproc);
+			racct_add_buf(curproc, bp, 0);
+			PROC_UNLOCK(curproc);
+		}
+#endif
+		curthread->td_ru.ru_inblock++;
+		error = bufwait(bp);
+		if (error != 0) {
+			brelse(bp);
+			return (error);
+		}
+	}
+	*bpp = bp;
+	return (0);
+}
+
 /*
  * Indirect blocks are now on the vnode for the file.  They are given negative
  * logical block numbers.  Indirect blocks are addressed by the negative
@@ -228,35 +269,10 @@ ext2_bmaparray(struct vnode *vp, daddr_t bn, daddr_t *
 		 */
 		if (bp)
 			bqrelse(bp);
+		error = readindir(vp, metalbn, daddr, &bp);
+		if (error != 0)
+			return (error);
 
-		bp = getblk(vp, metalbn, bsize, 0, 0, 0);
-		if ((bp->b_flags & B_CACHE) == 0) {
-#ifdef INVARIANTS
-			if (!daddr)
-				panic("ext2_bmaparray: indirect block not in cache");
-#endif
-			bp->b_blkno = blkptrtodb(ump, daddr);
-			bp->b_iocmd = BIO_READ;
-			bp->b_flags &= ~B_INVAL;
-			bp->b_ioflags &= ~BIO_ERROR;
-			vfs_busy_pages(bp, 0);
-			bp->b_iooffset = dbtob(bp->b_blkno);
-			bstrategy(bp);
-#ifdef RACCT
-			if (racct_enable) {
-				PROC_LOCK(curproc);
-				racct_add_buf(curproc, bp, 0);
-				PROC_UNLOCK(curproc);
-			}
-#endif
-			curthread->td_ru.ru_inblock++;
-			error = bufwait(bp);
-			if (error) {
-				brelse(bp);
-				return (error);
-			}
-		}
-
 		daddr = ((e2fs_daddr_t *)bp->b_data)[ap->in_off];
 		if (num == 1 && daddr && runp) {
 			for (bn = ap->in_off + 1;
@@ -294,6 +310,107 @@ ext2_bmaparray(struct vnode *vp, daddr_t bn, daddr_t *
 		*bnp = -1;
 	}
 	return (0);
+}
+
+static e2fs_lbn_t
+lbn_count(struct ext2mount *ump, int level)
+
+{
+	e2fs_lbn_t blockcnt;
+
+	for (blockcnt = 1; level > 0; level--)
+		blockcnt *= MNINDIR(ump);
+	return (blockcnt);
+}
+
+int
+ext2_bmap_seekdata(struct vnode *vp, off_t *offp)
+{
+	struct buf *bp;
+	struct indir a[EXT2_NIADDR + 1], *ap;
+	struct inode *ip;
+	struct mount *mp;
+	struct ext2mount *ump;
+	e2fs_daddr_t bn, daddr, nextbn;
+	uint64_t bsize;
+	off_t numblks;
+	int error, num, num1, off;
+
+	bp = NULL;
+	error = 0;
+	ip = VTOI(vp);
+	mp = vp->v_mount;
+	ump = VFSTOEXT2(mp);
+
+	if (vp->v_type != VREG || (ip->i_flags & SF_SNAPSHOT) != 0)
+		return (EINVAL);
+	if (*offp < 0 || *offp >= ip->i_size)
+		return (ENXIO);
+
+	bsize = mp->mnt_stat.f_iosize;
+	for (bn = *offp / bsize, numblks = howmany(ip->i_size, bsize);
+	    bn < numblks; bn = nextbn) {
+		if (bn < EXT2_NDADDR) {
+			daddr = ip->i_db[bn];
+			if (daddr != 0)
+				break;
+			nextbn = bn + 1;
+			continue;
+		}
+
+		ap = a;
+		error = ext2_getlbns(vp, bn, ap, &num);
+		if (error != 0)
+			break;
+		MPASS(num >= 2);
+		daddr = ip->i_ib[ap->in_off];
+		ap++, num--;
+		for (nextbn = EXT2_NDADDR, num1 = num - 1; num1 > 0; num1--)
+			nextbn += lbn_count(ump, num1);
+		if (daddr == 0) {
+			nextbn += lbn_count(ump, num);
+			continue;
+		}
+
+		for (; daddr != 0 && num > 0; ap++, num--) {
+			if (bp != NULL)
+				bqrelse(bp);
+			error = readindir(vp, ap->in_lbn, daddr, &bp);
+			if (error != 0)
+				return (error);
+
+			/*
+			 * Scan the indirect block until we find a non-zero
+			 * pointer.
+			 */
+			off = ap->in_off;
+			do {
+				daddr = ((e2fs_daddr_t *)bp->b_data)[off];
+			} while (daddr == 0 && ++off < MNINDIR(ump));
+			nextbn += off * lbn_count(ump, num - 1);
+
+			/*
+			 * We need to recompute the LBNs of indirect
+			 * blocks, so restart with the updated block offset.
+			 */
+			if (off != ap->in_off)
+				break;
+		}
+		if (num == 0) {
+			/*
+			 * We found a data block.
+			 */
+			bn = nextbn;
+			break;
+		}
+	}
+	if (bp != NULL)
+		bqrelse(bp);
+	if (bn >= numblks)
+		error = ENXIO;
+	if (error == 0 && *offp < bn * bsize)
+		*offp = bn * bsize;
+	return (error);
 }
 
 /*

Modified: head/sys/fs/ext2fs/ext2_extern.h
==============================================================================
--- head/sys/fs/ext2fs/ext2_extern.h	Tue Feb 18 16:37:48 2020	(r358072)
+++ head/sys/fs/ext2fs/ext2_extern.h	Tue Feb 18 16:39:57 2020	(r358073)
@@ -64,6 +64,7 @@ e4fs_daddr_t	ext2_blkpref(struct inode *, e2fs_lbn_t, 
 int	ext2_bmap(struct vop_bmap_args *);
 int	ext2_bmaparray(struct vnode *, daddr_t, daddr_t *, int *, int *);
 int	ext4_bmapext(struct vnode *, int32_t, int64_t *, int *, int *);
+int	ext2_bmap_seekdata(struct vnode *, off_t *);
 void	ext2_clusteracct(struct m_ext2fs *, char *, int, e4fs_daddr_t, int);
 void	ext2_dirbad(struct inode *ip, doff_t offset, char *how);
 int	ext2_ei2i(struct ext2fs_dinode *, struct inode *);

Modified: head/sys/fs/ext2fs/ext2_vnops.c
==============================================================================
--- head/sys/fs/ext2fs/ext2_vnops.c	Tue Feb 18 16:37:48 2020	(r358072)
+++ head/sys/fs/ext2fs/ext2_vnops.c	Tue Feb 18 16:39:57 2020	(r358073)
@@ -2157,11 +2157,24 @@ ext2_read(struct vop_read_args *ap)
 static int
 ext2_ioctl(struct vop_ioctl_args *ap)
 {
+	struct vnode *vp;
+	int error;
 
+	vp = ap->a_vp;
 	switch (ap->a_command) {
 	case FIOSEEKDATA:
+		if (!(VTOI(vp)->i_flag & IN_E4EXTENTS)) {
+			error = vn_lock(vp, LK_SHARED);
+			if (error == 0) {
+				error = ext2_bmap_seekdata(vp,
+				    (off_t *)ap->a_data);
+				VOP_UNLOCK(vp);
+			} else
+				error = EBADF;
+			return (error);
+		}
 	case FIOSEEKHOLE:
-		return (vn_bmap_seekhole(ap->a_vp, ap->a_command,
+		return (vn_bmap_seekhole(vp, ap->a_command,
 		    (off_t *)ap->a_data, ap->a_cred));
 	default:
 		return (ENOTTY);


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