1 files changed, 388 insertions, 0 deletions
diff --git a/fs/jfs/jfs_extent.c b/fs/jfs/jfs_extent.c
new file mode 100644
index 0000000000..63d21822d3
--- /dev/null
+++ b/fs/jfs/jfs_extent.c
@@ -0,0 +1,388 @@
+// SPDX-License-Identifier: GPL-2.0-or-later
+/*
+ *   Copyright (C) International Business Machines Corp., 2000-2004
+ */
+
+#include <linux/fs.h>
+#include <linux/quotaops.h>
+#include "jfs_incore.h"
+#include "jfs_inode.h"
+#include "jfs_superblock.h"
+#include "jfs_dmap.h"
+#include "jfs_extent.h"
+#include "jfs_debug.h"
+
+/*
+ * forward references
+ */
+static int extBalloc(struct inode *, s64, s64 *, s64 *);
+static s64 extRoundDown(s64 nb);
+
+#define DPD(a)		(printk("(a): %d\n",(a)))
+#define DPC(a)		(printk("(a): %c\n",(a)))
+#define DPL1(a)					\
+{						\
+	if ((a) >> 32)				\
+		printk("(a): %x%08x  ",(a));	\
+	else					\
+		printk("(a): %x  ",(a) << 32);	\
+}
+#define DPL(a)					\
+{						\
+	if ((a) >> 32)				\
+		printk("(a): %x%08x\n",(a));	\
+	else					\
+		printk("(a): %x\n",(a) << 32);	\
+}
+
+#define DPD1(a)		(printk("(a): %d  ",(a)))
+#define DPX(a)		(printk("(a): %08x\n",(a)))
+#define DPX1(a)		(printk("(a): %08x  ",(a)))
+#define DPS(a)		(printk("%s\n",(a)))
+#define DPE(a)		(printk("\nENTERING: %s\n",(a)))
+#define DPE1(a)		(printk("\nENTERING: %s",(a)))
+#define DPS1(a)		(printk("  %s  ",(a)))
+
+
+/*
+ * NAME:	extAlloc()
+ *
+ * FUNCTION:	allocate an extent for a specified page range within a
+ *		file.
+ *
+ * PARAMETERS:
+ *	ip	- the inode of the file.
+ *	xlen	- requested extent length.
+ *	pno	- the starting page number with the file.
+ *	xp	- pointer to an xad.  on entry, xad describes an
+ *		  extent that is used as an allocation hint if the
+ *		  xaddr of the xad is non-zero.  on successful exit,
+ *		  the xad describes the newly allocated extent.
+ *	abnr	- bool indicating whether the newly allocated extent
+ *		  should be marked as allocated but not recorded.
+ *
+ * RETURN VALUES:
+ *	0	- success
+ *	-EIO	- i/o error.
+ *	-ENOSPC	- insufficient disk resources.
+ */
+int
+extAlloc(struct inode *ip, s64 xlen, s64 pno, xad_t * xp, bool abnr)
+{
+	struct jfs_sb_info *sbi = JFS_SBI(ip->i_sb);
+	s64 nxlen, nxaddr, xoff, hint, xaddr = 0;
+	int rc;
+	int xflag;
+
+	/* This blocks if we are low on resources */
+	txBeginAnon(ip->i_sb);
+
+	/* Avoid race with jfs_commit_inode() */
+	mutex_lock(&JFS_IP(ip)->commit_mutex);
+
+	/* validate extent length */
+	if (xlen > MAXXLEN)
+		xlen = MAXXLEN;
+
+	/* get the page's starting extent offset */
+	xoff = pno << sbi->l2nbperpage;
+
+	/* check if an allocation hint was provided */
+	if ((hint = addressXAD(xp))) {
+		/* get the size of the extent described by the hint */
+		nxlen = lengthXAD(xp);
+
+		/* check if the hint is for the portion of the file
+		 * immediately previous to the current allocation
+		 * request and if hint extent has the same abnr
+		 * value as the current request.  if so, we can
+		 * extend the hint extent to include the current
+		 * extent if we can allocate the blocks immediately
+		 * following the hint extent.
+		 */
+		if (offsetXAD(xp) + nxlen == xoff &&
+		    abnr == ((xp->flag & XAD_NOTRECORDED) ? true : false))
+			xaddr = hint + nxlen;
+
+		/* adjust the hint to the last block of the extent */
+		hint += (nxlen - 1);
+	}
+
+	/* allocate the disk blocks for the extent.  initially, extBalloc()
+	 * will try to allocate disk blocks for the requested size (xlen).
+	 * if this fails (xlen contiguous free blocks not available), it'll
+	 * try to allocate a smaller number of blocks (producing a smaller
+	 * extent), with this smaller number of blocks consisting of the
+	 * requested number of blocks rounded down to the next smaller
+	 * power of 2 number (i.e. 16 -> 8).  it'll continue to round down
+	 * and retry the allocation until the number of blocks to allocate
+	 * is smaller than the number of blocks per page.
+	 */
+	nxlen = xlen;
+	if ((rc = extBalloc(ip, hint ? hint : INOHINT(ip), &nxlen, &nxaddr))) {
+		mutex_unlock(&JFS_IP(ip)->commit_mutex);
+		return (rc);
+	}
+
+	/* Allocate blocks to quota. */
+	rc = dquot_alloc_block(ip, nxlen);
+	if (rc) {
+		dbFree(ip, nxaddr, (s64) nxlen);
+		mutex_unlock(&JFS_IP(ip)->commit_mutex);
+		return rc;
+	}
+
+	/* determine the value of the extent flag */
+	xflag = abnr ? XAD_NOTRECORDED : 0;
+
+	/* if we can extend the hint extent to cover the current request,
+	 * extend it.  otherwise, insert a new extent to
+	 * cover the current request.
+	 */
+	if (xaddr && xaddr == nxaddr)
+		rc = xtExtend(0, ip, xoff, (int) nxlen, 0);
+	else
+		rc = xtInsert(0, ip, xflag, xoff, (int) nxlen, &nxaddr, 0);
+
+	/* if the extend or insert failed,
+	 * free the newly allocated blocks and return the error.
+	 */
+	if (rc) {
+		dbFree(ip, nxaddr, nxlen);
+		dquot_free_block(ip, nxlen);
+		mutex_unlock(&JFS_IP(ip)->commit_mutex);
+		return (rc);
+	}
+
+	/* set the results of the extent allocation */
+	XADaddress(xp, nxaddr);
+	XADlength(xp, nxlen);
+	XADoffset(xp, xoff);
+	xp->flag = xflag;
+
+	mark_inode_dirty(ip);
+
+	mutex_unlock(&JFS_IP(ip)->commit_mutex);
+	/*
+	 * COMMIT_SyncList flags an anonymous tlock on page that is on
+	 * sync list.
+	 * We need to commit the inode to get the page written to the disk.
+	 */
+	if (test_and_clear_cflag(COMMIT_Synclist,ip))
+		jfs_commit_inode(ip, 0);
+
+	return (0);
+}
+
+/*
+ * NAME:	extHint()
+ *
+ * FUNCTION:	produce an extent allocation hint for a file offset.
+ *
+ * PARAMETERS:
+ *	ip	- the inode of the file.
+ *	offset  - file offset for which the hint is needed.
+ *	xp	- pointer to the xad that is to be filled in with
+ *		  the hint.
+ *
+ * RETURN VALUES:
+ *	0	- success
+ *	-EIO	- i/o error.
+ */
+int extHint(struct inode *ip, s64 offset, xad_t * xp)
+{
+	struct super_block *sb = ip->i_sb;
+	int nbperpage = JFS_SBI(sb)->nbperpage;
+	s64 prev;
+	int rc = 0;
+	s64 xaddr;
+	int xlen;
+	int xflag;
+
+	/* init the hint as "no hint provided" */
+	XADaddress(xp, 0);
+
+	/* determine the starting extent offset of the page previous
+	 * to the page containing the offset.
+	 */
+	prev = ((offset & ~POFFSET) >> JFS_SBI(sb)->l2bsize) - nbperpage;
+
+	/* if the offset is in the first page of the file, no hint provided.
+	 */
+	if (prev < 0)
+		goto out;
+
+	rc = xtLookup(ip, prev, nbperpage, &xflag, &xaddr, &xlen, 0);
+
+	if ((rc == 0) && xlen) {
+		if (xlen != nbperpage) {
+			jfs_error(ip->i_sb, "corrupt xtree\n");
+			rc = -EIO;
+		}
+		XADaddress(xp, xaddr);
+		XADlength(xp, xlen);
+		XADoffset(xp, prev);
+		/*
+		 * only preserve the abnr flag within the xad flags
+		 * of the returned hint.
+		 */
+		xp->flag  = xflag & XAD_NOTRECORDED;
+	} else
+		rc = 0;
+
+out:
+	return (rc);
+}
+
+
+/*
+ * NAME:	extRecord()
+ *
+ * FUNCTION:	change a page with a file from not recorded to recorded.
+ *
+ * PARAMETERS:
+ *	ip	- inode of the file.
+ *	cp	- cbuf of the file page.
+ *
+ * RETURN VALUES:
+ *	0	- success
+ *	-EIO	- i/o error.
+ *	-ENOSPC	- insufficient disk resources.
+ */
+int extRecord(struct inode *ip, xad_t * xp)
+{
+	int rc;
+
+	txBeginAnon(ip->i_sb);
+
+	mutex_lock(&JFS_IP(ip)->commit_mutex);
+
+	/* update the extent */
+	rc = xtUpdate(0, ip, xp);
+
+	mutex_unlock(&JFS_IP(ip)->commit_mutex);
+	return rc;
+}
+
+/*
+ * NAME:	extBalloc()
+ *
+ * FUNCTION:	allocate disk blocks to form an extent.
+ *
+ *		initially, we will try to allocate disk blocks for the
+ *		requested size (nblocks).  if this fails (nblocks
+ *		contiguous free blocks not available), we'll try to allocate
+ *		a smaller number of blocks (producing a smaller extent), with
+ *		this smaller number of blocks consisting of the requested
+ *		number of blocks rounded down to the next smaller power of 2
+ *		number (i.e. 16 -> 8).  we'll continue to round down and
+ *		retry the allocation until the number of blocks to allocate
+ *		is smaller than the number of blocks per page.
+ *
+ * PARAMETERS:
+ *	ip	 - the inode of the file.
+ *	hint	 - disk block number to be used as an allocation hint.
+ *	*nblocks - pointer to an s64 value.  on entry, this value specifies
+ *		   the desired number of block to be allocated. on successful
+ *		   exit, this value is set to the number of blocks actually
+ *		   allocated.
+ *	blkno	 - pointer to a block address that is filled in on successful
+ *		   return with the starting block number of the newly
+ *		   allocated block range.
+ *
+ * RETURN VALUES:
+ *	0	- success
+ *	-EIO	- i/o error.
+ *	-ENOSPC	- insufficient disk resources.
+ */
+static int
+extBalloc(struct inode *ip, s64 hint, s64 * nblocks, s64 * blkno)
+{
+	struct jfs_inode_info *ji = JFS_IP(ip);
+	struct jfs_sb_info *sbi = JFS_SBI(ip->i_sb);
+	s64 nb, nblks, daddr, max;
+	int rc, nbperpage = sbi->nbperpage;
+	struct bmap *bmp = sbi->bmap;
+	int ag;
+
+	/* get the number of blocks to initially attempt to allocate.
+	 * we'll first try the number of blocks requested unless this
+	 * number is greater than the maximum number of contiguous free
+	 * blocks in the map. in that case, we'll start off with the
+	 * maximum free.
+	 */
+
+	/* give up if no space left */
+	if (bmp->db_maxfreebud == -1)
+		return -ENOSPC;
+
+	max = (s64) 1 << bmp->db_maxfreebud;
+	if (*nblocks >= max && *nblocks > nbperpage)
+		nb = nblks = (max > nbperpage) ? max : nbperpage;
+	else
+		nb = nblks = *nblocks;
+
+	/* try to allocate blocks */
+	while ((rc = dbAlloc(ip, hint, nb, &daddr)) != 0) {
+		/* if something other than an out of space error,
+		 * stop and return this error.
+		 */
+		if (rc != -ENOSPC)
+			return (rc);
+
+		/* decrease the allocation request size */
+		nb = min(nblks, extRoundDown(nb));
+
+		/* give up if we cannot cover a page */
+		if (nb < nbperpage)
+			return (rc);
+	}
+
+	*nblocks = nb;
+	*blkno = daddr;
+
+	if (S_ISREG(ip->i_mode) && (ji->fileset == FILESYSTEM_I)) {
+		ag = BLKTOAG(daddr, sbi);
+		spin_lock_irq(&ji->ag_lock);
+		if (ji->active_ag == -1) {
+			atomic_inc(&bmp->db_active[ag]);
+			ji->active_ag = ag;
+		} else if (ji->active_ag != ag) {
+			atomic_dec(&bmp->db_active[ji->active_ag]);
+			atomic_inc(&bmp->db_active[ag]);
+			ji->active_ag = ag;
+		}
+		spin_unlock_irq(&ji->ag_lock);
+	}
+
+	return (0);
+}
+
+/*
+ * NAME:	extRoundDown()
+ *
+ * FUNCTION:	round down a specified number of blocks to the next
+ *		smallest power of 2 number.
+ *
+ * PARAMETERS:
+ *	nb	- the inode of the file.
+ *
+ * RETURN VALUES:
+ *	next smallest power of 2 number.
+ */
+static s64 extRoundDown(s64 nb)
+{
+	int i;
+	u64 m, k;
+
+	for (i = 0, m = (u64) 1 << 63; i < 64; i++, m >>= 1) {
+		if (m & nb)
+			break;
+	}
+
+	i = 63 - i;
+	k = (u64) 1 << i;
+	k = ((k - 1) & nb) ? k : k >> 1;
+
+	return (k);
+}