diff options
Diffstat (limited to 'fs/ocfs2/extent_map.c')
| -rw-r--r-- | fs/ocfs2/extent_map.c | 994 |
1 files changed, 994 insertions, 0 deletions
diff --git a/fs/ocfs2/extent_map.c b/fs/ocfs2/extent_map.c new file mode 100644 index 00000000000..f2fb40cd296 --- /dev/null +++ b/fs/ocfs2/extent_map.c @@ -0,0 +1,994 @@ +/* -*- mode: c; c-basic-offset: 8; -*- + * vim: noexpandtab sw=8 ts=8 sts=0: + * + * extent_map.c + * + * In-memory extent map for OCFS2. Man, this code was prettier in + * the library. + * + * Copyright (C) 2004 Oracle. All rights reserved. + * + * This program is free software; you can redistribute it and/or + * modify it under the terms of the GNU General Public + * License, version 2, as published by the Free Software Foundation. + * + * 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 021110-1307, USA. + */ + +#include <linux/fs.h> +#include <linux/init.h> +#include <linux/types.h> +#include <linux/slab.h> +#include <linux/rbtree.h> + +#define MLOG_MASK_PREFIX ML_EXTENT_MAP +#include <cluster/masklog.h> + +#include "ocfs2.h" + +#include "extent_map.h" +#include "inode.h" +#include "super.h" + +#include "buffer_head_io.h" + + +/* + * SUCK SUCK SUCK + * Our headers are so bad that struct ocfs2_extent_map is in ocfs.h + */ + +struct ocfs2_extent_map_entry { + struct rb_node e_node; + int e_tree_depth; + struct ocfs2_extent_rec e_rec; +}; + +struct ocfs2_em_insert_context { + int need_left; + int need_right; + struct ocfs2_extent_map_entry *new_ent; + struct ocfs2_extent_map_entry *old_ent; + struct ocfs2_extent_map_entry *left_ent; + struct ocfs2_extent_map_entry *right_ent; +}; + +static kmem_cache_t *ocfs2_em_ent_cachep = NULL; + + +static struct ocfs2_extent_map_entry * +ocfs2_extent_map_lookup(struct ocfs2_extent_map *em, + u32 cpos, u32 clusters, + struct rb_node ***ret_p, + struct rb_node **ret_parent); +static int ocfs2_extent_map_insert(struct inode *inode, + struct ocfs2_extent_rec *rec, + int tree_depth); +static int ocfs2_extent_map_insert_entry(struct ocfs2_extent_map *em, + struct ocfs2_extent_map_entry *ent); +static int ocfs2_extent_map_find_leaf(struct inode *inode, + u32 cpos, u32 clusters, + struct ocfs2_extent_list *el); +static int ocfs2_extent_map_lookup_read(struct inode *inode, + u32 cpos, u32 clusters, + struct ocfs2_extent_map_entry **ret_ent); +static int ocfs2_extent_map_try_insert(struct inode *inode, + struct ocfs2_extent_rec *rec, + int tree_depth, + struct ocfs2_em_insert_context *ctxt); + +/* returns 1 only if the rec contains all the given clusters -- that is that + * rec's cpos is <= the cluster cpos and that the rec endpoint (cpos + + * clusters) is >= the argument's endpoint */ +static int ocfs2_extent_rec_contains_clusters(struct ocfs2_extent_rec *rec, + u32 cpos, u32 clusters) +{ + if (le32_to_cpu(rec->e_cpos) > cpos) + return 0; + if (cpos + clusters > le32_to_cpu(rec->e_cpos) + + le32_to_cpu(rec->e_clusters)) + return 0; + return 1; +} + + +/* + * Find an entry in the tree that intersects the region passed in. + * Note that this will find straddled intervals, it is up to the + * callers to enforce any boundary conditions. + * + * Callers must hold ip_lock. This lookup is not guaranteed to return + * a tree_depth 0 match, and as such can race inserts if the lock + * were not held. + * + * The rb_node garbage lets insertion share the search. Trivial + * callers pass NULL. + */ +static struct ocfs2_extent_map_entry * +ocfs2_extent_map_lookup(struct ocfs2_extent_map *em, + u32 cpos, u32 clusters, + struct rb_node ***ret_p, + struct rb_node **ret_parent) +{ + struct rb_node **p = &em->em_extents.rb_node; + struct rb_node *parent = NULL; + struct ocfs2_extent_map_entry *ent = NULL; + + while (*p) + { + parent = *p; + ent = rb_entry(parent, struct ocfs2_extent_map_entry, + e_node); + if ((cpos + clusters) <= le32_to_cpu(ent->e_rec.e_cpos)) { + p = &(*p)->rb_left; + ent = NULL; + } else if (cpos >= (le32_to_cpu(ent->e_rec.e_cpos) + + le32_to_cpu(ent->e_rec.e_clusters))) { + p = &(*p)->rb_right; + ent = NULL; + } else + break; + } + + if (ret_p != NULL) + *ret_p = p; + if (ret_parent != NULL) + *ret_parent = parent; + return ent; +} + +/* + * Find the leaf containing the interval we want. While we're on our + * way down the tree, fill in every record we see at any depth, because + * we might want it later. + * + * Note that this code is run without ip_lock. That's because it + * sleeps while reading. If someone is also filling the extent list at + * the same time we are, we might have to restart. + */ +static int ocfs2_extent_map_find_leaf(struct inode *inode, + u32 cpos, u32 clusters, + struct ocfs2_extent_list *el) +{ + int i, ret; + struct buffer_head *eb_bh = NULL; + u64 blkno; + u32 rec_end; + struct ocfs2_extent_block *eb; + struct ocfs2_extent_rec *rec; + + /* + * The bh data containing the el cannot change here, because + * we hold alloc_sem. So we can do this without other + * locks. + */ + while (el->l_tree_depth) + { + blkno = 0; + for (i = 0; i < le16_to_cpu(el->l_next_free_rec); i++) { + rec = &el->l_recs[i]; + rec_end = (le32_to_cpu(rec->e_cpos) + + le32_to_cpu(rec->e_clusters)); + + ret = -EBADR; + if (rec_end > OCFS2_I(inode)->ip_clusters) { + mlog_errno(ret); + goto out_free; + } + + if (rec_end <= cpos) { + ret = ocfs2_extent_map_insert(inode, rec, + le16_to_cpu(el->l_tree_depth)); + if (ret && (ret != -EEXIST)) { + mlog_errno(ret); + goto out_free; + } + continue; + } + if ((cpos + clusters) <= le32_to_cpu(rec->e_cpos)) { + ret = ocfs2_extent_map_insert(inode, rec, + le16_to_cpu(el->l_tree_depth)); + if (ret && (ret != -EEXIST)) { + mlog_errno(ret); + goto out_free; + } + continue; + } + + /* + * We've found a record that matches our + * interval. We don't insert it because we're + * about to traverse it. + */ + + /* Check to see if we're stradling */ + ret = -ESRCH; + if (!ocfs2_extent_rec_contains_clusters(rec, + cpos, + clusters)) { + mlog_errno(ret); + goto out_free; + } + + /* + * If we've already found a record, the el has + * two records covering the same interval. + * EEEK! + */ + ret = -EBADR; + if (blkno) { + mlog_errno(ret); + goto out_free; + } + + blkno = le64_to_cpu(rec->e_blkno); + } + + /* + * We don't support holes, and we're still up + * in the branches, so we'd better have found someone + */ + ret = -EBADR; + if (!blkno) { + mlog_errno(ret); + goto out_free; + } + + if (eb_bh) { + brelse(eb_bh); + eb_bh = NULL; + } + ret = ocfs2_read_block(OCFS2_SB(inode->i_sb), + blkno, &eb_bh, OCFS2_BH_CACHED, + inode); + if (ret) { + mlog_errno(ret); + goto out_free; + } + eb = (struct ocfs2_extent_block *)eb_bh->b_data; + if (!OCFS2_IS_VALID_EXTENT_BLOCK(eb)) { + OCFS2_RO_ON_INVALID_EXTENT_BLOCK(inode->i_sb, eb); + ret = -EIO; + goto out_free; + } + el = &eb->h_list; + } + + if (el->l_tree_depth) + BUG(); + + for (i = 0; i < le16_to_cpu(el->l_next_free_rec); i++) { + rec = &el->l_recs[i]; + ret = ocfs2_extent_map_insert(inode, rec, + le16_to_cpu(el->l_tree_depth)); + if (ret) { + mlog_errno(ret); + goto out_free; + } + } + + ret = 0; + +out_free: + if (eb_bh) + brelse(eb_bh); + + return ret; +} + +/* + * This lookup actually will read from disk. It has one invariant: + * It will never re-traverse blocks. This means that all inserts should + * be new regions or more granular regions (both allowed by insert). + */ +static int ocfs2_extent_map_lookup_read(struct inode *inode, + u32 cpos, + u32 clusters, + struct ocfs2_extent_map_entry **ret_ent) +{ + int ret; + u64 blkno; + struct ocfs2_extent_map *em = &OCFS2_I(inode)->ip_map; + struct ocfs2_extent_map_entry *ent; + struct buffer_head *bh = NULL; + struct ocfs2_extent_block *eb; + struct ocfs2_dinode *di; + struct ocfs2_extent_list *el; + + spin_lock(&OCFS2_I(inode)->ip_lock); + ent = ocfs2_extent_map_lookup(em, cpos, clusters, NULL, NULL); + if (ent) { + if (!ent->e_tree_depth) { + spin_unlock(&OCFS2_I(inode)->ip_lock); + *ret_ent = ent; + return 0; + } + blkno = le64_to_cpu(ent->e_rec.e_blkno); + spin_unlock(&OCFS2_I(inode)->ip_lock); + + ret = ocfs2_read_block(OCFS2_SB(inode->i_sb), blkno, &bh, + OCFS2_BH_CACHED, inode); + if (ret) { + mlog_errno(ret); + if (bh) + brelse(bh); + return ret; + } + eb = (struct ocfs2_extent_block *)bh->b_data; + if (!OCFS2_IS_VALID_EXTENT_BLOCK(eb)) { + OCFS2_RO_ON_INVALID_EXTENT_BLOCK(inode->i_sb, eb); + brelse(bh); + return -EIO; + } + el = &eb->h_list; + } else { + spin_unlock(&OCFS2_I(inode)->ip_lock); + + ret = ocfs2_read_block(OCFS2_SB(inode->i_sb), + OCFS2_I(inode)->ip_blkno, &bh, + OCFS2_BH_CACHED, inode); + if (ret) { + mlog_errno(ret); + if (bh) + brelse(bh); + return ret; + } + di = (struct ocfs2_dinode *)bh->b_data; + if (!OCFS2_IS_VALID_DINODE(di)) { + brelse(bh); + OCFS2_RO_ON_INVALID_DINODE(inode->i_sb, di); + return -EIO; + } + el = &di->id2.i_list; + } + + ret = ocfs2_extent_map_find_leaf(inode, cpos, clusters, el); + brelse(bh); + if (ret) { + mlog_errno(ret); + return ret; + } + + ent = ocfs2_extent_map_lookup(em, cpos, clusters, NULL, NULL); + if (!ent) { + ret = -ESRCH; + mlog_errno(ret); + return ret; + } + + if (ent->e_tree_depth) + BUG(); /* FIXME: Make sure this isn't a corruption */ + + *ret_ent = ent; + + return 0; +} + +/* + * Callers must hold ip_lock. This can insert pieces of the tree, + * thus racing lookup if the lock weren't held. + */ +static int ocfs2_extent_map_insert_entry(struct ocfs2_extent_map *em, + struct ocfs2_extent_map_entry *ent) +{ + struct rb_node **p, *parent; + struct ocfs2_extent_map_entry *old_ent; + + old_ent = ocfs2_extent_map_lookup(em, le32_to_cpu(ent->e_rec.e_cpos), + le32_to_cpu(ent->e_rec.e_clusters), + &p, &parent); + if (old_ent) + return -EEXIST; + + rb_link_node(&ent->e_node, parent, p); + rb_insert_color(&ent->e_node, &em->em_extents); + + return 0; +} + + +/* + * Simple rule: on any return code other than -EAGAIN, anything left + * in the insert_context will be freed. + */ +static int ocfs2_extent_map_try_insert(struct inode *inode, + struct ocfs2_extent_rec *rec, + int tree_depth, + struct ocfs2_em_insert_context *ctxt) +{ + int ret; + struct ocfs2_extent_map *em = &OCFS2_I(inode)->ip_map; + struct ocfs2_extent_map_entry *old_ent; + + ctxt->need_left = 0; + ctxt->need_right = 0; + ctxt->old_ent = NULL; + + spin_lock(&OCFS2_I(inode)->ip_lock); + ret = ocfs2_extent_map_insert_entry(em, ctxt->new_ent); + if (!ret) { + ctxt->new_ent = NULL; + goto out_unlock; + } + + old_ent = ocfs2_extent_map_lookup(em, le32_to_cpu(rec->e_cpos), + le32_to_cpu(rec->e_clusters), NULL, + NULL); + + if (!old_ent) + BUG(); + + ret = -EEXIST; + if (old_ent->e_tree_depth < tree_depth) + goto out_unlock; + + if (old_ent->e_tree_depth == tree_depth) { + if (!memcmp(rec, &old_ent->e_rec, + sizeof(struct ocfs2_extent_rec))) + ret = 0; + + /* FIXME: Should this be ESRCH/EBADR??? */ + goto out_unlock; + } + + /* + * We do it in this order specifically so that no actual tree + * changes occur until we have all the pieces we need. We + * don't want malloc failures to leave an inconsistent tree. + * Whenever we drop the lock, another process could be + * inserting. Also note that, if another process just beat us + * to an insert, we might not need the same pieces we needed + * the first go round. In the end, the pieces we need will + * be used, and the pieces we don't will be freed. + */ + ctxt->need_left = !!(le32_to_cpu(rec->e_cpos) > + le32_to_cpu(old_ent->e_rec.e_cpos)); + ctxt->need_right = !!((le32_to_cpu(old_ent->e_rec.e_cpos) + + le32_to_cpu(old_ent->e_rec.e_clusters)) > + (le32_to_cpu(rec->e_cpos) + le32_to_cpu(rec->e_clusters))); + ret = -EAGAIN; + if (ctxt->need_left) { + if (!ctxt->left_ent) + goto out_unlock; + *(ctxt->left_ent) = *old_ent; + ctxt->left_ent->e_rec.e_clusters = + cpu_to_le32(le32_to_cpu(rec->e_cpos) - + le32_to_cpu(ctxt->left_ent->e_rec.e_cpos)); + } + if (ctxt->need_right) { + if (!ctxt->right_ent) + goto out_unlock; + *(ctxt->right_ent) = *old_ent; + ctxt->right_ent->e_rec.e_cpos = + cpu_to_le32(le32_to_cpu(rec->e_cpos) + + le32_to_cpu(rec->e_clusters)); + ctxt->right_ent->e_rec.e_clusters = + cpu_to_le32((le32_to_cpu(old_ent->e_rec.e_cpos) + + le32_to_cpu(old_ent->e_rec.e_clusters)) - + le32_to_cpu(ctxt->right_ent->e_rec.e_cpos)); + } + + rb_erase(&old_ent->e_node, &em->em_extents); + /* Now that he's erased, set him up for deletion */ + ctxt->old_ent = old_ent; + + if (ctxt->need_left) { + ret = ocfs2_extent_map_insert_entry(em, + ctxt->left_ent); + if (ret) + goto out_unlock; + ctxt->left_ent = NULL; + } + + if (ctxt->need_right) { + ret = ocfs2_extent_map_insert_entry(em, + ctxt->right_ent); + if (ret) + goto out_unlock; + ctxt->right_ent = NULL; + } + + ret = ocfs2_extent_map_insert_entry(em, ctxt->new_ent); + + if (!ret) + ctxt->new_ent = NULL; + +out_unlock: + spin_unlock(&OCFS2_I(inode)->ip_lock); + + return ret; +} + + +static int ocfs2_extent_map_insert(struct inode *inode, + struct ocfs2_extent_rec *rec, + int tree_depth) +{ + int ret; + struct ocfs2_em_insert_context ctxt = {0, }; + + if ((le32_to_cpu(rec->e_cpos) + le32_to_cpu(rec->e_clusters)) > + OCFS2_I(inode)->ip_map.em_clusters) { + ret = -EBADR; + mlog_errno(ret); + return ret; + } + + /* Zero e_clusters means a truncated tail record. It better be EOF */ + if (!rec->e_clusters) { + if ((le32_to_cpu(rec->e_cpos) + le32_to_cpu(rec->e_clusters)) != + OCFS2_I(inode)->ip_map.em_clusters) { + ret = -EBADR; + mlog_errno(ret); + return ret; + } + + /* Ignore the truncated tail */ + return 0; + } + + ret = -ENOMEM; + ctxt.new_ent = kmem_cache_alloc(ocfs2_em_ent_cachep, + GFP_KERNEL); + if (!ctxt.new_ent) { + mlog_errno(ret); + return ret; + } + + ctxt.new_ent->e_rec = *rec; + ctxt.new_ent->e_tree_depth = tree_depth; + + do { + ret = -ENOMEM; + if (ctxt.need_left && !ctxt.left_ent) { + ctxt.left_ent = + kmem_cache_alloc(ocfs2_em_ent_cachep, + GFP_KERNEL); + if (!ctxt.left_ent) + break; + } + if (ctxt.need_right && !ctxt.right_ent) { + ctxt.right_ent = + kmem_cache_alloc(ocfs2_em_ent_cachep, + GFP_KERNEL); + if (!ctxt.right_ent) + break; + } + + ret = ocfs2_extent_map_try_insert(inode, rec, + tree_depth, &ctxt); + } while (ret == -EAGAIN); + + if (ret < 0) + mlog_errno(ret); + + if (ctxt.left_ent) + kmem_cache_free(ocfs2_em_ent_cachep, ctxt.left_ent); + if (ctxt.right_ent) + kmem_cache_free(ocfs2_em_ent_cachep, ctxt.right_ent); + if (ctxt.old_ent) + kmem_cache_free(ocfs2_em_ent_cachep, ctxt.old_ent); + if (ctxt.new_ent) + kmem_cache_free(ocfs2_em_ent_cachep, ctxt.new_ent); + + return ret; +} + +/* + * Append this record to the tail of the extent map. It must be + * tree_depth 0. The record might be an extension of an existing + * record, and as such that needs to be handled. eg: + * + * Existing record in the extent map: + * + * cpos = 10, len = 10 + * |---------| + * + * New Record: + * + * cpos = 10, len = 20 + * |------------------| + * + * The passed record is the new on-disk record. The new_clusters value + * is how many clusters were added to the file. If the append is a + * contiguous append, the new_clusters has been added to + * rec->e_clusters. If the append is an entirely new extent, then + * rec->e_clusters is == new_clusters. + */ +int ocfs2_extent_map_append(struct inode *inode, + struct ocfs2_extent_rec *rec, + u32 new_clusters) +{ + int ret; + struct ocfs2_extent_map *em = &OCFS2_I(inode)->ip_map; + struct ocfs2_extent_map_entry *ent; + struct ocfs2_extent_rec *old; + + BUG_ON(!new_clusters); + BUG_ON(le32_to_cpu(rec->e_clusters) < new_clusters); + + if (em->em_clusters < OCFS2_I(inode)->ip_clusters) { + /* + * Size changed underneath us on disk. Drop any + * straddling records and update our idea of + * i_clusters + */ + ocfs2_extent_map_drop(inode, em->em_clusters - 1); + em->em_clusters = OCFS2_I(inode)->ip_clusters; + } + + mlog_bug_on_msg((le32_to_cpu(rec->e_cpos) + + le32_to_cpu(rec->e_clusters)) != + (em->em_clusters + new_clusters), + "Inode %"MLFu64":\n" + "rec->e_cpos = %u + rec->e_clusters = %u = %u\n" + "em->em_clusters = %u + new_clusters = %u = %u\n", + OCFS2_I(inode)->ip_blkno, + le32_to_cpu(rec->e_cpos), le32_to_cpu(rec->e_clusters), + le32_to_cpu(rec->e_cpos) + le32_to_cpu(rec->e_clusters), + em->em_clusters, new_clusters, + em->em_clusters + new_clusters); + + em->em_clusters += new_clusters; + + ret = -ENOENT; + if (le32_to_cpu(rec->e_clusters) > new_clusters) { + /* This is a contiguous append */ + ent = ocfs2_extent_map_lookup(em, le32_to_cpu(rec->e_cpos), 1, + NULL, NULL); + if (ent) { + old = &ent->e_rec; + BUG_ON((le32_to_cpu(rec->e_cpos) + + le32_to_cpu(rec->e_clusters)) != + (le32_to_cpu(old->e_cpos) + + le32_to_cpu(old->e_clusters) + + new_clusters)); + if (ent->e_tree_depth == 0) { + BUG_ON(le32_to_cpu(old->e_cpos) != + le32_to_cpu(rec->e_cpos)); + BUG_ON(le64_to_cpu(old->e_blkno) != + le64_to_cpu(rec->e_blkno)); + ret = 0; + } + /* + * Let non-leafs fall through as -ENOENT to + * force insertion of the new leaf. + */ + le32_add_cpu(&old->e_clusters, new_clusters); + } + } + + if (ret == -ENOENT) + ret = ocfs2_extent_map_insert(inode, rec, 0); + if (ret < 0) + mlog_errno(ret); + return ret; +} + +#if 0 +/* Code here is included but defined out as it completes the extent + * map api and may be used in the future. */ + +/* + * Look up the record containing this cluster offset. This record is + * part of the extent map. Do not free it. Any changes you make to + * it will reflect in the extent map. So, if your last extent + * is (cpos = 10, clusters = 10) and you truncate the file by 5 + * clusters, you can do: + * + * ret = ocfs2_extent_map_get_rec(em, orig_size - 5, &rec); + * rec->e_clusters -= 5; + * + * The lookup does not read from disk. If the map isn't filled in for + * an entry, you won't find it. + * + * Also note that the returned record is valid until alloc_sem is + * dropped. After that, truncate and extend can happen. Caveat Emptor. + */ +int ocfs2_extent_map_get_rec(struct inode *inode, u32 cpos, + struct ocfs2_extent_rec **rec, + int *tree_depth) +{ + int ret = -ENOENT; + struct ocfs2_extent_map *em = &OCFS2_I(inode)->ip_map; + struct ocfs2_extent_map_entry *ent; + + *rec = NULL; + + if (cpos >= OCFS2_I(inode)->ip_clusters) + return -EINVAL; + + if (cpos >= em->em_clusters) { + /* + * Size changed underneath us on disk. Drop any + * straddling records and update our idea of + * i_clusters + */ + ocfs2_extent_map_drop(inode, em->em_clusters - 1); + em->em_clusters = OCFS2_I(inode)->ip_clusters ; + } + + ent = ocfs2_extent_map_lookup(&OCFS2_I(inode)->ip_map, cpos, 1, + NULL, NULL); + + if (ent) { + *rec = &ent->e_rec; + if (tree_depth) + *tree_depth = ent->e_tree_depth; + ret = 0; + } + + return ret; +} + +int ocfs2_extent_map_get_clusters(struct inode *inode, + u32 v_cpos, int count, + u32 *p_cpos, int *ret_count) +{ + int ret; + u32 coff, ccount; + struct ocfs2_extent_map *em = &OCFS2_I(inode)->ip_map; + struct ocfs2_extent_map_entry *ent = NULL; + + *p_cpos = ccount = 0; + + if ((v_cpos + count) > OCFS2_I(inode)->ip_clusters) + return -EINVAL; + + if ((v_cpos + count) > em->em_clusters) { + /* + * Size changed underneath us on disk. Drop any + * straddling records and update our idea of + * i_clusters + */ + ocfs2_extent_map_drop(inode, em->em_clusters - 1); + em->em_clusters = OCFS2_I(inode)->ip_clusters; + } + + + ret = ocfs2_extent_map_lookup_read(inode, v_cpos, count, &ent); + if (ret) + return ret; + + if (ent) { + /* We should never find ourselves straddling an interval */ + if (!ocfs2_extent_rec_contains_clusters(&ent->e_rec, + v_cpos, + count)) + return -ESRCH; + + coff = v_cpos - le32_to_cpu(ent->e_rec.e_cpos); + *p_cpos = ocfs2_blocks_to_clusters(inode->i_sb, + le64_to_cpu(ent->e_rec.e_blkno)) + + coff; + + if (ret_count) + *ret_count = le32_to_cpu(ent->e_rec.e_clusters) - coff; + + return 0; + } + + + return -ENOENT; +} + +#endif /* 0 */ + +int ocfs2_extent_map_get_blocks(struct inode *inode, + u64 v_blkno, int count, + u64 *p_blkno, int *ret_count) +{ + int ret; + u64 boff; + u32 cpos, clusters; + int bpc = ocfs2_clusters_to_blocks(inode->i_sb, 1); + struct ocfs2_extent_map_entry *ent = NULL; + struct ocfs2_extent_map *em = &OCFS2_I(inode)->ip_map; + struct ocfs2_extent_rec *rec; + + *p_blkno = 0; + + cpos = ocfs2_blocks_to_clusters(inode->i_sb, v_blkno); + clusters = ocfs2_blocks_to_clusters(inode->i_sb, + (u64)count + bpc - 1); + if ((cpos + clusters) > OCFS2_I(inode)->ip_clusters) { + ret = -EINVAL; + mlog_errno(ret); + return ret; + } + + if ((cpos + clusters) > em->em_clusters) { + /* + * Size changed underneath us on disk. Drop any + * straddling records and update our idea of + * i_clusters + */ + ocfs2_extent_map_drop(inode, em->em_clusters - 1); + em->em_clusters = OCFS2_I(inode)->ip_clusters; + } + + ret = ocfs2_extent_map_lookup_read(inode, cpos, clusters, &ent); + if (ret) { + mlog_errno(ret); + return ret; + } + + if (ent) + { + rec = &ent->e_rec; + + /* We should never find ourselves straddling an interval */ + if (!ocfs2_extent_rec_contains_clusters(rec, cpos, clusters)) { + ret = -ESRCH; + mlog_errno(ret); + return ret; + } + + boff = ocfs2_clusters_to_blocks(inode->i_sb, cpos - + le32_to_cpu(rec->e_cpos)); + boff += (v_blkno & (u64)(bpc - 1)); + *p_blkno = le64_to_cpu(rec->e_blkno) + boff; + + if (ret_count) { + *ret_count = ocfs2_clusters_to_blocks(inode->i_sb, + le32_to_cpu(rec->e_clusters)) - boff; + } + + return 0; + } + + return -ENOENT; +} + +int ocfs2_extent_map_init(struct inode *inode) +{ + struct ocfs2_extent_map *em = &OCFS2_I(inode)->ip_map; + + em->em_extents = RB_ROOT; + em->em_clusters = 0; + + return 0; +} + +/* Needs the lock */ +static void __ocfs2_extent_map_drop(struct inode *inode, + u32 new_clusters, + struct rb_node **free_head, + struct ocfs2_extent_map_entry **tail_ent) +{ + struct rb_node *node, *next; + struct ocfs2_extent_map *em = &OCFS2_I(inode)->ip_map; + struct ocfs2_extent_map_entry *ent; + + *free_head = NULL; + + ent = NULL; + node = rb_last(&em->em_extents); + while (node) + { + next = rb_prev(node); + + ent = rb_entry(node, struct ocfs2_extent_map_entry, + e_node); + if (le32_to_cpu(ent->e_rec.e_cpos) < new_clusters) + break; + + rb_erase(&ent->e_node, &em->em_extents); + + node->rb_right = *free_head; + *free_head = node; + + ent = NULL; + node = next; + } + + /* Do we have an entry straddling new_clusters? */ + if (tail_ent) { + if (ent && + ((le32_to_cpu(ent->e_rec.e_cpos) + + le32_to_cpu(ent->e_rec.e_clusters)) > new_clusters)) + *tail_ent = ent; + else + *tail_ent = NULL; + } +} + +static void __ocfs2_extent_map_drop_cleanup(struct rb_node *free_head) +{ + struct rb_node *node; + struct ocfs2_extent_map_entry *ent; + + while (free_head) { + node = free_head; + free_head = node->rb_right; + + ent = rb_entry(node, struct ocfs2_extent_map_entry, + e_node); + kmem_cache_free(ocfs2_em_ent_cachep, ent); + } +} + +/* + * Remove all entries past new_clusters, inclusive of an entry that + * contains new_clusters. This is effectively a cache forget. + * + * If you want to also clip the last extent by some number of clusters, + * you need to call ocfs2_extent_map_trunc(). + * This code does not check or modify ip_clusters. + */ +int ocfs2_extent_map_drop(struct inode *inode, u32 new_clusters) +{ + struct rb_node *free_head = NULL; + struct ocfs2_extent_map *em = &OCFS2_I(inode)->ip_map; + struct ocfs2_extent_map_entry *ent; + + spin_lock(&OCFS2_I(inode)->ip_lock); + + __ocfs2_extent_map_drop(inode, new_clusters, &free_head, &ent); + + if (ent) { + rb_erase(&ent->e_node, &em->em_extents); + ent->e_node.rb_right = free_head; + free_head = &ent->e_node; + } + + spin_unlock(&OCFS2_I(inode)->ip_lock); + + if (free_head) + __ocfs2_extent_map_drop_cleanup(free_head); + + return 0; +} + +/* + * Remove all entries past new_clusters and also clip any extent + * straddling new_clusters, if there is one. This does not check + * or modify ip_clusters + */ +int ocfs2_extent_map_trunc(struct inode *inode, u32 new_clusters) +{ + struct rb_node *free_head = NULL; + struct ocfs2_extent_map_entry *ent = NULL; + + spin_lock(&OCFS2_I(inode)->ip_lock); + + __ocfs2_extent_map_drop(inode, new_clusters, &free_head, &ent); + + if (ent) + ent->e_rec.e_clusters = cpu_to_le32(new_clusters - + le32_to_cpu(ent->e_rec.e_cpos)); + + OCFS2_I(inode)->ip_map.em_clusters = new_clusters; + + spin_unlock(&OCFS2_I(inode)->ip_lock); + + if (free_head) + __ocfs2_extent_map_drop_cleanup(free_head); + + return 0; +} + +int __init init_ocfs2_extent_maps(void) +{ + ocfs2_em_ent_cachep = + kmem_cache_create("ocfs2_em_ent", + sizeof(struct ocfs2_extent_map_entry), + 0, SLAB_HWCACHE_ALIGN, NULL, NULL); + if (!ocfs2_em_ent_cachep) + return -ENOMEM; + + return 0; +} + +void __exit exit_ocfs2_extent_maps(void) +{ + kmem_cache_destroy(ocfs2_em_ent_cachep); +} |