+
+/*
+ * Return a pointer to the indirection array entry containing the
+ * extent record for filesystem block bno. Store the index of the
+ * target irec in *erp_idxp.
+ */
+xfs_ext_irec_t *
+xfs_iext_bno_to_irec(
+ xfs_ifork_t *ifp, /* inode fork pointer */
+ xfs_fileoff_t bno, /* block number to search for */
+ int *erp_idxp) /* irec index of target ext list */
+{
+ xfs_ext_irec_t *erp = NULL; /* indirection array pointer */
+ xfs_ext_irec_t *erp_next; /* next indirection array entry */
+ xfs_extnum_t erp_idx; /* indirection array index */
+ int nlists; /* number of extent irec's (lists) */
+ int high; /* binary search upper limit */
+ int low; /* binary search lower limit */
+
+ ASSERT(ifp->if_flags & XFS_IFEXTIREC);
+ nlists = ifp->if_real_bytes / XFS_IEXT_BUFSZ;
+ erp_idx = 0;
+ low = 0;
+ high = nlists - 1;
+ while (low <= high) {
+ erp_idx = (low + high) >> 1;
+ erp = &ifp->if_u1.if_ext_irec[erp_idx];
+ erp_next = erp_idx < nlists - 1 ? erp + 1 : NULL;
+ if (bno < xfs_bmbt_get_startoff(erp->er_extbuf)) {
+ high = erp_idx - 1;
+ } else if (erp_next && bno >=
+ xfs_bmbt_get_startoff(erp_next->er_extbuf)) {
+ low = erp_idx + 1;
+ } else {
+ break;
+ }
+ }
+ *erp_idxp = erp_idx;
+ return erp;
+}
+
+/*
+ * Return a pointer to the indirection array entry containing the
+ * extent record at file extent index *idxp. Store the index of the
+ * target irec in *erp_idxp and store the page index of the target
+ * extent record in *idxp.
+ */
+xfs_ext_irec_t *
+xfs_iext_idx_to_irec(
+ xfs_ifork_t *ifp, /* inode fork pointer */
+ xfs_extnum_t *idxp, /* extent index (file -> page) */
+ int *erp_idxp, /* pointer to target irec */
+ int realloc) /* new bytes were just added */
+{
+ xfs_ext_irec_t *prev; /* pointer to previous irec */
+ xfs_ext_irec_t *erp = NULL; /* pointer to current irec */
+ int erp_idx; /* indirection array index */
+ int nlists; /* number of irec's (ex lists) */
+ int high; /* binary search upper limit */
+ int low; /* binary search lower limit */
+ xfs_extnum_t page_idx = *idxp; /* extent index in target list */
+
+ ASSERT(ifp->if_flags & XFS_IFEXTIREC);
+ ASSERT(page_idx >= 0 && page_idx <=
+ ifp->if_bytes / (uint)sizeof(xfs_bmbt_rec_t));
+ nlists = ifp->if_real_bytes / XFS_IEXT_BUFSZ;
+ erp_idx = 0;
+ low = 0;
+ high = nlists - 1;
+
+ /* Binary search extent irec's */
+ while (low <= high) {
+ erp_idx = (low + high) >> 1;
+ erp = &ifp->if_u1.if_ext_irec[erp_idx];
+ prev = erp_idx > 0 ? erp - 1 : NULL;
+ if (page_idx < erp->er_extoff || (page_idx == erp->er_extoff &&
+ realloc && prev && prev->er_extcount < XFS_LINEAR_EXTS)) {
+ high = erp_idx - 1;
+ } else if (page_idx > erp->er_extoff + erp->er_extcount ||
+ (page_idx == erp->er_extoff + erp->er_extcount &&
+ !realloc)) {
+ low = erp_idx + 1;
+ } else if (page_idx == erp->er_extoff + erp->er_extcount &&
+ erp->er_extcount == XFS_LINEAR_EXTS) {
+ ASSERT(realloc);
+ page_idx = 0;
+ erp_idx++;
+ erp = erp_idx < nlists ? erp + 1 : NULL;
+ break;
+ } else {
+ page_idx -= erp->er_extoff;
+ break;
+ }
+ }
+ *idxp = page_idx;
+ *erp_idxp = erp_idx;
+ return(erp);
+}
+
+/*
+ * Allocate and initialize an indirection array once the space needed
+ * for incore extents increases above XFS_IEXT_BUFSZ.
+ */
+void
+xfs_iext_irec_init(
+ xfs_ifork_t *ifp) /* inode fork pointer */
+{
+ xfs_ext_irec_t *erp; /* indirection array pointer */
+ xfs_extnum_t nextents; /* number of extents in file */
+
+ ASSERT(!(ifp->if_flags & XFS_IFEXTIREC));
+ nextents = ifp->if_bytes / (uint)sizeof(xfs_bmbt_rec_t);
+ ASSERT(nextents <= XFS_LINEAR_EXTS);
+
+ erp = (xfs_ext_irec_t *)
+ kmem_alloc(sizeof(xfs_ext_irec_t), KM_SLEEP);
+
+ if (nextents == 0) {
+ ifp->if_u1.if_extents = (xfs_bmbt_rec_t *)
+ kmem_alloc(XFS_IEXT_BUFSZ, KM_SLEEP);
+ } else if (!ifp->if_real_bytes) {
+ xfs_iext_inline_to_direct(ifp, XFS_IEXT_BUFSZ);
+ } else if (ifp->if_real_bytes < XFS_IEXT_BUFSZ) {
+ xfs_iext_realloc_direct(ifp, XFS_IEXT_BUFSZ);
+ }
+ erp->er_extbuf = ifp->if_u1.if_extents;
+ erp->er_extcount = nextents;
+ erp->er_extoff = 0;
+
+ ifp->if_flags |= XFS_IFEXTIREC;
+ ifp->if_real_bytes = XFS_IEXT_BUFSZ;
+ ifp->if_bytes = nextents * sizeof(xfs_bmbt_rec_t);
+ ifp->if_u1.if_ext_irec = erp;
+
+ return;
+}
+
+/*
+ * Allocate and initialize a new entry in the indirection array.
+ */
+xfs_ext_irec_t *
+xfs_iext_irec_new(
+ xfs_ifork_t *ifp, /* inode fork pointer */
+ int erp_idx) /* index for new irec */
+{
+ xfs_ext_irec_t *erp; /* indirection array pointer */
+ int i; /* loop counter */
+ int nlists; /* number of irec's (ex lists) */
+
+ ASSERT(ifp->if_flags & XFS_IFEXTIREC);
+ nlists = ifp->if_real_bytes / XFS_IEXT_BUFSZ;
+
+ /* Resize indirection array */
+ xfs_iext_realloc_indirect(ifp, ++nlists *
+ sizeof(xfs_ext_irec_t));
+ /*
+ * Move records down in the array so the
+ * new page can use erp_idx.
+ */
+ erp = ifp->if_u1.if_ext_irec;
+ for (i = nlists - 1; i > erp_idx; i--) {
+ memmove(&erp[i], &erp[i-1], sizeof(xfs_ext_irec_t));
+ }
+ ASSERT(i == erp_idx);
+
+ /* Initialize new extent record */
+ erp = ifp->if_u1.if_ext_irec;
+ erp[erp_idx].er_extbuf = (xfs_bmbt_rec_t *)
+ kmem_alloc(XFS_IEXT_BUFSZ, KM_SLEEP);
+ ifp->if_real_bytes = nlists * XFS_IEXT_BUFSZ;
+ memset(erp[erp_idx].er_extbuf, 0, XFS_IEXT_BUFSZ);
+ erp[erp_idx].er_extcount = 0;
+ erp[erp_idx].er_extoff = erp_idx > 0 ?
+ erp[erp_idx-1].er_extoff + erp[erp_idx-1].er_extcount : 0;
+ return (&erp[erp_idx]);
+}
+
+/*
+ * Remove a record from the indirection array.
+ */
+void
+xfs_iext_irec_remove(
+ xfs_ifork_t *ifp, /* inode fork pointer */
+ int erp_idx) /* irec index to remove */
+{
+ xfs_ext_irec_t *erp; /* indirection array pointer */
+ int i; /* loop counter */
+ int nlists; /* number of irec's (ex lists) */
+
+ ASSERT(ifp->if_flags & XFS_IFEXTIREC);
+ nlists = ifp->if_real_bytes / XFS_IEXT_BUFSZ;
+ erp = &ifp->if_u1.if_ext_irec[erp_idx];
+ if (erp->er_extbuf) {
+ xfs_iext_irec_update_extoffs(ifp, erp_idx + 1,
+ -erp->er_extcount);
+ kmem_free(erp->er_extbuf, XFS_IEXT_BUFSZ);
+ }
+ /* Compact extent records */
+ erp = ifp->if_u1.if_ext_irec;
+ for (i = erp_idx; i < nlists - 1; i++) {
+ memmove(&erp[i], &erp[i+1], sizeof(xfs_ext_irec_t));
+ }
+ /*
+ * Manually free the last extent record from the indirection
+ * array. A call to xfs_iext_realloc_indirect() with a size
+ * of zero would result in a call to xfs_iext_destroy() which
+ * would in turn call this function again, creating a nasty
+ * infinite loop.
+ */
+ if (--nlists) {
+ xfs_iext_realloc_indirect(ifp,
+ nlists * sizeof(xfs_ext_irec_t));
+ } else {
+ kmem_free(ifp->if_u1.if_ext_irec,
+ sizeof(xfs_ext_irec_t));
+ }
+ ifp->if_real_bytes = nlists * XFS_IEXT_BUFSZ;
+}
+
+/*
+ * This is called to clean up large amounts of unused memory allocated
+ * by the indirection array. Before compacting anything though, verify
+ * that the indirection array is still needed and switch back to the
+ * linear extent list (or even the inline buffer) if possible. The
+ * compaction policy is as follows:
+ *
+ * Full Compaction: Extents fit into a single page (or inline buffer)
+ * Full Compaction: Extents occupy less than 10% of allocated space
+ * Partial Compaction: Extents occupy > 10% and < 50% of allocated space
+ * No Compaction: Extents occupy at least 50% of allocated space
+ */
+void
+xfs_iext_irec_compact(
+ xfs_ifork_t *ifp) /* inode fork pointer */
+{
+ xfs_extnum_t nextents; /* number of extents in file */
+ int nlists; /* number of irec's (ex lists) */
+
+ ASSERT(ifp->if_flags & XFS_IFEXTIREC);
+ nlists = ifp->if_real_bytes / XFS_IEXT_BUFSZ;
+ nextents = ifp->if_bytes / (uint)sizeof(xfs_bmbt_rec_t);
+
+ if (nextents == 0) {
+ xfs_iext_destroy(ifp);
+ } else if (nextents <= XFS_INLINE_EXTS) {
+ xfs_iext_indirect_to_direct(ifp);
+ xfs_iext_direct_to_inline(ifp, nextents);
+ } else if (nextents <= XFS_LINEAR_EXTS) {
+ xfs_iext_indirect_to_direct(ifp);
+ } else if (nextents < (nlists * XFS_LINEAR_EXTS) >> 3) {
+ xfs_iext_irec_compact_full(ifp);
+ } else if (nextents < (nlists * XFS_LINEAR_EXTS) >> 1) {
+ xfs_iext_irec_compact_pages(ifp);
+ }
+}
+
+/*
+ * Combine extents from neighboring extent pages.
+ */
+void
+xfs_iext_irec_compact_pages(
+ xfs_ifork_t *ifp) /* inode fork pointer */
+{
+ xfs_ext_irec_t *erp, *erp_next;/* pointers to irec entries */
+ int erp_idx = 0; /* indirection array index */
+ int nlists; /* number of irec's (ex lists) */
+
+ ASSERT(ifp->if_flags & XFS_IFEXTIREC);
+ nlists = ifp->if_real_bytes / XFS_IEXT_BUFSZ;
+ while (erp_idx < nlists - 1) {
+ erp = &ifp->if_u1.if_ext_irec[erp_idx];
+ erp_next = erp + 1;
+ if (erp_next->er_extcount <=
+ (XFS_LINEAR_EXTS - erp->er_extcount)) {
+ memmove(&erp->er_extbuf[erp->er_extcount],
+ erp_next->er_extbuf, erp_next->er_extcount *
+ sizeof(xfs_bmbt_rec_t));
+ erp->er_extcount += erp_next->er_extcount;
+ /*
+ * Free page before removing extent record
+ * so er_extoffs don't get modified in
+ * xfs_iext_irec_remove.
+ */
+ kmem_free(erp_next->er_extbuf, XFS_IEXT_BUFSZ);
+ erp_next->er_extbuf = NULL;
+ xfs_iext_irec_remove(ifp, erp_idx + 1);
+ nlists = ifp->if_real_bytes / XFS_IEXT_BUFSZ;
+ } else {
+ erp_idx++;
+ }
+ }
+}
+
+/*
+ * Fully compact the extent records managed by the indirection array.
+ */
+void
+xfs_iext_irec_compact_full(
+ xfs_ifork_t *ifp) /* inode fork pointer */
+{
+ xfs_bmbt_rec_t *ep, *ep_next; /* extent record pointers */
+ xfs_ext_irec_t *erp, *erp_next; /* extent irec pointers */
+ int erp_idx = 0; /* extent irec index */
+ int ext_avail; /* empty entries in ex list */
+ int ext_diff; /* number of exts to add */
+ int nlists; /* number of irec's (ex lists) */
+
+ ASSERT(ifp->if_flags & XFS_IFEXTIREC);
+ nlists = ifp->if_real_bytes / XFS_IEXT_BUFSZ;
+ erp = ifp->if_u1.if_ext_irec;
+ ep = &erp->er_extbuf[erp->er_extcount];
+ erp_next = erp + 1;
+ ep_next = erp_next->er_extbuf;
+ while (erp_idx < nlists - 1) {
+ ext_avail = XFS_LINEAR_EXTS - erp->er_extcount;
+ ext_diff = MIN(ext_avail, erp_next->er_extcount);
+ memcpy(ep, ep_next, ext_diff * sizeof(xfs_bmbt_rec_t));
+ erp->er_extcount += ext_diff;
+ erp_next->er_extcount -= ext_diff;
+ /* Remove next page */
+ if (erp_next->er_extcount == 0) {
+ /*
+ * Free page before removing extent record
+ * so er_extoffs don't get modified in
+ * xfs_iext_irec_remove.
+ */
+ kmem_free(erp_next->er_extbuf,
+ erp_next->er_extcount * sizeof(xfs_bmbt_rec_t));
+ erp_next->er_extbuf = NULL;
+ xfs_iext_irec_remove(ifp, erp_idx + 1);
+ erp = &ifp->if_u1.if_ext_irec[erp_idx];
+ nlists = ifp->if_real_bytes / XFS_IEXT_BUFSZ;
+ /* Update next page */
+ } else {
+ /* Move rest of page up to become next new page */
+ memmove(erp_next->er_extbuf, ep_next,
+ erp_next->er_extcount * sizeof(xfs_bmbt_rec_t));
+ ep_next = erp_next->er_extbuf;
+ memset(&ep_next[erp_next->er_extcount], 0,
+ (XFS_LINEAR_EXTS - erp_next->er_extcount) *
+ sizeof(xfs_bmbt_rec_t));
+ }
+ if (erp->er_extcount == XFS_LINEAR_EXTS) {
+ erp_idx++;
+ if (erp_idx < nlists)
+ erp = &ifp->if_u1.if_ext_irec[erp_idx];
+ else
+ break;
+ }
+ ep = &erp->er_extbuf[erp->er_extcount];
+ erp_next = erp + 1;
+ ep_next = erp_next->er_extbuf;
+ }
+}
+
+/*
+ * This is called to update the er_extoff field in the indirection
+ * array when extents have been added or removed from one of the
+ * extent lists. erp_idx contains the irec index to begin updating
+ * at and ext_diff contains the number of extents that were added
+ * or removed.
+ */
+void
+xfs_iext_irec_update_extoffs(
+ xfs_ifork_t *ifp, /* inode fork pointer */
+ int erp_idx, /* irec index to update */
+ int ext_diff) /* number of new extents */
+{
+ int i; /* loop counter */
+ int nlists; /* number of irec's (ex lists */
+
+ ASSERT(ifp->if_flags & XFS_IFEXTIREC);
+ nlists = ifp->if_real_bytes / XFS_IEXT_BUFSZ;
+ for (i = erp_idx; i < nlists; i++) {
+ ifp->if_u1.if_ext_irec[i].er_extoff += ext_diff;
+ }
+}