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-rw-r--r--fs/jfs/jfs_extent.c668
1 files changed, 668 insertions, 0 deletions
diff --git a/fs/jfs/jfs_extent.c b/fs/jfs/jfs_extent.c
new file mode 100644
index 00000000000..1953acb7926
--- /dev/null
+++ b/fs/jfs/jfs_extent.c
@@ -0,0 +1,668 @@
+/*
+ * Copyright (C) International Business Machines Corp., 2000-2004
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; either version 2 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See
+ * the GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, write to the Free Software
+ * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
+ */
+
+#include <linux/fs.h>
+#include <linux/quotaops.h>
+#include "jfs_incore.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 *);
+#ifdef _NOTYET
+static int extBrealloc(struct inode *, s64, s64, s64 *, s64 *);
+#endif
+static s64 extRoundDown(s64 nb);
+
+/*
+ * external references
+ */
+extern int jfs_commit_inode(struct inode *, int);
+
+
+#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 - boolean_t 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, boolean_t 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() */
+ down(&JFS_IP(ip)->commit_sem);
+
+ /* 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 contigious free blocks not avaliable), 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))) {
+ up(&JFS_IP(ip)->commit_sem);
+ return (rc);
+ }
+
+ /* Allocate blocks to quota. */
+ if (DQUOT_ALLOC_BLOCK(ip, nxlen)) {
+ dbFree(ip, nxaddr, (s64) nxlen);
+ up(&JFS_IP(ip)->commit_sem);
+ return -EDQUOT;
+ }
+
+ /* determine the value of the extent flag */
+ xflag = (abnr == TRUE) ? 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);
+ up(&JFS_IP(ip)->commit_sem);
+ 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);
+
+ up(&JFS_IP(ip)->commit_sem);
+ /*
+ * COMMIT_SyncList flags an anonymous tlock on page that is on
+ * sync list.
+ * We need to commit the inode to get the page written disk.
+ */
+ if (test_and_clear_cflag(COMMIT_Synclist,ip))
+ jfs_commit_inode(ip, 0);
+
+ return (0);
+}
+
+
+#ifdef _NOTYET
+/*
+ * NAME: extRealloc()
+ *
+ * FUNCTION: extend the allocation of a file extent containing a
+ * partial back last page.
+ *
+ * PARAMETERS:
+ * ip - the inode of the file.
+ * cp - cbuf for the partial backed last page.
+ * xlen - request size of the resulting extent.
+ * xp - pointer to an xad. on successful exit, the xad
+ * describes the newly allocated extent.
+ * abnr - boolean_t 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 extRealloc(struct inode *ip, s64 nxlen, xad_t * xp, boolean_t abnr)
+{
+ struct super_block *sb = ip->i_sb;
+ s64 xaddr, xlen, nxaddr, delta, xoff;
+ s64 ntail, nextend, ninsert;
+ int rc, nbperpage = JFS_SBI(sb)->nbperpage;
+ int xflag;
+
+ /* This blocks if we are low on resources */
+ txBeginAnon(ip->i_sb);
+
+ down(&JFS_IP(ip)->commit_sem);
+ /* validate extent length */
+ if (nxlen > MAXXLEN)
+ nxlen = MAXXLEN;
+
+ /* get the extend (partial) page's disk block address and
+ * number of blocks.
+ */
+ xaddr = addressXAD(xp);
+ xlen = lengthXAD(xp);
+ xoff = offsetXAD(xp);
+
+ /* if the extend page is abnr and if the request is for
+ * the extent to be allocated and recorded,
+ * make the page allocated and recorded.
+ */
+ if ((xp->flag & XAD_NOTRECORDED) && !abnr) {
+ xp->flag = 0;
+ if ((rc = xtUpdate(0, ip, xp)))
+ goto exit;
+ }
+
+ /* try to allocated the request number of blocks for the
+ * extent. dbRealloc() first tries to satisfy the request
+ * by extending the allocation in place. otherwise, it will
+ * try to allocate a new set of blocks large enough for the
+ * request. in satisfying a request, dbReAlloc() may allocate
+ * less than what was request but will always allocate enough
+ * space as to satisfy the extend page.
+ */
+ if ((rc = extBrealloc(ip, xaddr, xlen, &nxlen, &nxaddr)))
+ goto exit;
+
+ /* Allocat blocks to quota. */
+ if (DQUOT_ALLOC_BLOCK(ip, nxlen)) {
+ dbFree(ip, nxaddr, (s64) nxlen);
+ up(&JFS_IP(ip)->commit_sem);
+ return -EDQUOT;
+ }
+
+ delta = nxlen - xlen;
+
+ /* check if the extend page is not abnr but the request is abnr
+ * and the allocated disk space is for more than one page. if this
+ * is the case, there is a miss match of abnr between the extend page
+ * and the one or more pages following the extend page. as a result,
+ * two extents will have to be manipulated. the first will be that
+ * of the extent of the extend page and will be manipulated thru
+ * an xtExtend() or an xtTailgate(), depending upon whether the
+ * disk allocation occurred as an inplace extension. the second
+ * extent will be manipulated (created) through an xtInsert() and
+ * will be for the pages following the extend page.
+ */
+ if (abnr && (!(xp->flag & XAD_NOTRECORDED)) && (nxlen > nbperpage)) {
+ ntail = nbperpage;
+ nextend = ntail - xlen;
+ ninsert = nxlen - nbperpage;
+
+ xflag = XAD_NOTRECORDED;
+ } else {
+ ntail = nxlen;
+ nextend = delta;
+ ninsert = 0;
+
+ xflag = xp->flag;
+ }
+
+ /* if we were able to extend the disk allocation in place,
+ * extend the extent. otherwise, move the extent to a
+ * new disk location.
+ */
+ if (xaddr == nxaddr) {
+ /* extend the extent */
+ if ((rc = xtExtend(0, ip, xoff + xlen, (int) nextend, 0))) {
+ dbFree(ip, xaddr + xlen, delta);
+ DQUOT_FREE_BLOCK(ip, nxlen);
+ goto exit;
+ }
+ } else {
+ /*
+ * move the extent to a new location:
+ *
+ * xtTailgate() accounts for relocated tail extent;
+ */
+ if ((rc = xtTailgate(0, ip, xoff, (int) ntail, nxaddr, 0))) {
+ dbFree(ip, nxaddr, nxlen);
+ DQUOT_FREE_BLOCK(ip, nxlen);
+ goto exit;
+ }
+ }
+
+
+ /* check if we need to also insert a new extent */
+ if (ninsert) {
+ /* perform the insert. if it fails, free the blocks
+ * to be inserted and make it appear that we only did
+ * the xtExtend() or xtTailgate() above.
+ */
+ xaddr = nxaddr + ntail;
+ if (xtInsert (0, ip, xflag, xoff + ntail, (int) ninsert,
+ &xaddr, 0)) {
+ dbFree(ip, xaddr, (s64) ninsert);
+ delta = nextend;
+ nxlen = ntail;
+ xflag = 0;
+ }
+ }
+
+ /* set the return results */
+ XADaddress(xp, nxaddr);
+ XADlength(xp, nxlen);
+ XADoffset(xp, xoff);
+ xp->flag = xflag;
+
+ mark_inode_dirty(ip);
+exit:
+ up(&JFS_IP(ip)->commit_sem);
+ return (rc);
+}
+#endif /* _NOTYET */
+
+
+/*
+ * 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;
+ struct xadlist xadl;
+ struct lxdlist lxdl;
+ lxd_t lxd;
+ s64 prev;
+ int rc, nbperpage = JFS_SBI(sb)->nbperpage;
+
+ /* 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 offsets in the first page of the file,
+ * no hint provided.
+ */
+ if (prev < 0)
+ return (0);
+
+ /* prepare to lookup the previous page's extent info */
+ lxdl.maxnlxd = 1;
+ lxdl.nlxd = 1;
+ lxdl.lxd = &lxd;
+ LXDoffset(&lxd, prev)
+ LXDlength(&lxd, nbperpage);
+
+ xadl.maxnxad = 1;
+ xadl.nxad = 0;
+ xadl.xad = xp;
+
+ /* perform the lookup */
+ if ((rc = xtLookupList(ip, &lxdl, &xadl, 0)))
+ return (rc);
+
+ /* check if not extent exists for the previous page.
+ * this is possible for sparse files.
+ */
+ if (xadl.nxad == 0) {
+// assert(ISSPARSE(ip));
+ return (0);
+ }
+
+ /* only preserve the abnr flag within the xad flags
+ * of the returned hint.
+ */
+ xp->flag &= XAD_NOTRECORDED;
+
+ if(xadl.nxad != 1 || lengthXAD(xp) != nbperpage) {
+ jfs_error(ip->i_sb, "extHint: corrupt xtree");
+ return -EIO;
+ }
+
+ return (0);
+}
+
+
+/*
+ * 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);
+
+ down(&JFS_IP(ip)->commit_sem);
+
+ /* update the extent */
+ rc = xtUpdate(0, ip, xp);
+
+ up(&JFS_IP(ip)->commit_sem);
+ return rc;
+}
+
+
+#ifdef _NOTYET
+/*
+ * NAME: extFill()
+ *
+ * FUNCTION: allocate disk space for a file page that represents
+ * a file hole.
+ *
+ * PARAMETERS:
+ * ip - the inode of the file.
+ * cp - cbuf of the file page represent the hole.
+ *
+ * RETURN VALUES:
+ * 0 - success
+ * -EIO - i/o error.
+ * -ENOSPC - insufficient disk resources.
+ */
+int extFill(struct inode *ip, xad_t * xp)
+{
+ int rc, nbperpage = JFS_SBI(ip->i_sb)->nbperpage;
+ s64 blkno = offsetXAD(xp) >> ip->i_blksize;
+
+// assert(ISSPARSE(ip));
+
+ /* initialize the extent allocation hint */
+ XADaddress(xp, 0);
+
+ /* allocate an extent to fill the hole */
+ if ((rc = extAlloc(ip, nbperpage, blkno, xp, FALSE)))
+ return (rc);
+
+ assert(lengthPXD(xp) == nbperpage);
+
+ return (0);
+}
+#endif /* _NOTYET */
+
+
+/*
+ * 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
+ * contigious free blocks not avaliable), 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 contigious free
+ * blocks in the map. in that case, we'll start off with the
+ * maximum free.
+ */
+ 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);
+}
+
+
+#ifdef _NOTYET
+/*
+ * NAME: extBrealloc()
+ *
+ * FUNCTION: attempt to extend an extent's allocation.
+ *
+ * initially, we will try to extend the extent's allocation
+ * in place. if this fails, we'll try to move the extent
+ * to a new set of blocks. if moving the extent, we initially
+ * will try to allocate disk blocks for the requested size
+ * (nnew). if this fails (nnew contigious free blocks not
+ * avaliable), 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.
+ * blkno - starting block number of the extents current allocation.
+ * nblks - number of blocks within the extents current allocation.
+ * newnblks - pointer to a s64 value. on entry, this value is the
+ * the new desired extent size (number of blocks). on
+ * successful exit, this value is set to the extent's actual
+ * new size (new number of blocks).
+ * newblkno - the starting block number of the extents new allocation.
+ *
+ * RETURN VALUES:
+ * 0 - success
+ * -EIO - i/o error.
+ * -ENOSPC - insufficient disk resources.
+ */
+static int
+extBrealloc(struct inode *ip,
+ s64 blkno, s64 nblks, s64 * newnblks, s64 * newblkno)
+{
+ int rc;
+
+ /* try to extend in place */
+ if ((rc = dbExtend(ip, blkno, nblks, *newnblks - nblks)) == 0) {
+ *newblkno = blkno;
+ return (0);
+ } else {
+ if (rc != -ENOSPC)
+ return (rc);
+ }
+
+ /* in place extension not possible.
+ * try to move the extent to a new set of blocks.
+ */
+ return (extBalloc(ip, blkno, newnblks, newblkno));
+}
+#endif /* _NOTYET */
+
+
+/*
+ * 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);
+}
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