// SPDX-License-Identifier: GPL-2.0-only /* * vfsv0 quota IO operations on file */ #include <linux/errno.h> #include <linux/fs.h> #include <linux/mount.h> #include <linux/dqblk_v2.h> #include <linux/kernel.h> #include <linux/init.h> #include <linux/module.h> #include <linux/slab.h> #include <linux/quotaops.h> #include <asm/byteorder.h> #include "quota_tree.h" MODULE_AUTHOR("Jan Kara"); MODULE_DESCRIPTION("Quota trie support"); MODULE_LICENSE("GPL"); #define __QUOTA_QT_PARANOIA static int __get_index(struct qtree_mem_dqinfo *info, qid_t id, int depth) { unsigned int epb = info->dqi_usable_bs >> 2; depth = info->dqi_qtree_depth - depth - 1; while (depth--) id /= epb; return id % epb; } static int get_index(struct qtree_mem_dqinfo *info, struct kqid qid, int depth) { qid_t id = from_kqid(&init_user_ns, qid); return __get_index(info, id, depth); } /* Number of entries in one blocks */ static int qtree_dqstr_in_blk(struct qtree_mem_dqinfo *info) { return (info->dqi_usable_bs - sizeof(struct qt_disk_dqdbheader)) / info->dqi_entry_size; } static char *getdqbuf(size_t size) { char *buf = kmalloc(size, GFP_NOFS); if (!buf) printk(KERN_WARNING "VFS: Not enough memory for quota buffers.\n"); return buf; } static ssize_t read_blk(struct qtree_mem_dqinfo *info, uint blk, char *buf) { struct super_block *sb = info->dqi_sb; memset(buf, 0, info->dqi_usable_bs); return sb->s_op->quota_read(sb, info->dqi_type, buf, info->dqi_usable_bs, blk << info->dqi_blocksize_bits); } static ssize_t write_blk(struct qtree_mem_dqinfo *info, uint blk, char *buf) { struct super_block *sb = info->dqi_sb; ssize_t ret; ret = sb->s_op->quota_write(sb, info->dqi_type, buf, info->dqi_usable_bs, blk << info->dqi_blocksize_bits); if (ret != info->dqi_usable_bs) { quota_error(sb, "dquota write failed"); if (ret >= 0) ret = -EIO; } return ret; } /* Remove empty block from list and return it */ static int get_free_dqblk(struct qtree_mem_dqinfo *info) { char *buf = getdqbuf(info->dqi_usable_bs); struct qt_disk_dqdbheader *dh = (struct qt_disk_dqdbheader *)buf; int ret, blk; if (!buf) return -ENOMEM; if (info->dqi_free_blk) { blk = info->dqi_free_blk; ret = read_blk(info, blk, buf); if (ret < 0) goto out_buf; info->dqi_free_blk = le32_to_cpu(dh->dqdh_next_free); } else { memset(buf, 0, info->dqi_usable_bs); /* Assure block allocation... */ ret = write_blk(info, info->dqi_blocks, buf); if (ret < 0) goto out_buf; blk = info->dqi_blocks++; } mark_info_dirty(info->dqi_sb, info->dqi_type); ret = blk; out_buf: kfree(buf); return ret; } /* Insert empty block to the list */ static int put_free_dqblk(struct qtree_mem_dqinfo *info, char *buf, uint blk) { struct qt_disk_dqdbheader *dh = (struct qt_disk_dqdbheader *)buf; int err; dh->dqdh_next_free = cpu_to_le32(info->dqi_free_blk); dh->dqdh_prev_free = cpu_to_le32(0); dh->dqdh_entries = cpu_to_le16(0); err = write_blk(info, blk, buf); if (err < 0) return err; info->dqi_free_blk = blk; mark_info_dirty(info->dqi_sb, info->dqi_type); return 0; } /* Remove given block from the list of blocks with free entries */ static int remove_free_dqentry(struct qtree_mem_dqinfo *info, char *buf, uint blk) { char *tmpbuf = getdqbuf(info->dqi_usable_bs); struct qt_disk_dqdbheader *dh = (struct qt_disk_dqdbheader *)buf; uint nextblk = le32_to_cpu(dh->dqdh_next_free); uint prevblk = le32_to_cpu(dh->dqdh_prev_free); int err; if (!tmpbuf) return -ENOMEM; if (nextblk) { err = read_blk(info, nextblk, tmpbuf); if (err < 0) goto out_buf; ((struct qt_disk_dqdbheader *)tmpbuf)->dqdh_prev_free = dh->dqdh_prev_free; err = write_blk(info, nextblk, tmpbuf); if (err < 0) goto out_buf; } if (prevblk) { err = read_blk(info, prevblk, tmpbuf); if (err < 0) goto out_buf; ((struct qt_disk_dqdbheader *)tmpbuf)->dqdh_next_free = dh->dqdh_next_free; err = write_blk(info, prevblk, tmpbuf); if (err < 0) goto out_buf; } else { info->dqi_free_entry = nextblk; mark_info_dirty(info->dqi_sb, info->dqi_type); } kfree(tmpbuf); dh->dqdh_next_free = dh->dqdh_prev_free = cpu_to_le32(0); /* No matter whether write succeeds block is out of list */ if (write_blk(info, blk, buf) < 0) quota_error(info->dqi_sb, "Can't write block (%u) " "with free entries", blk); return 0; out_buf: kfree(tmpbuf); return err; } /* Insert given block to the beginning of list with free entries */ static int insert_free_dqentry(struct qtree_mem_dqinfo *info, char *buf, uint blk) { char *tmpbuf = getdqbuf(info->dqi_usable_bs); struct qt_disk_dqdbheader *dh = (struct qt_disk_dqdbheader *)buf; int err; if (!tmpbuf) return -ENOMEM; dh->dqdh_next_free = cpu_to_le32(info->dqi_free_entry); dh->dqdh_prev_free = cpu_to_le32(0); err = write_blk(info, blk, buf); if (err < 0) goto out_buf; if (info->dqi_free_entry) { err = read_blk(info, info->dqi_free_entry, tmpbuf); if (err < 0) goto out_buf; ((struct qt_disk_dqdbheader *)tmpbuf)->dqdh_prev_free = cpu_to_le32(blk); err = write_blk(info, info->dqi_free_entry, tmpbuf); if (err < 0) goto out_buf; } kfree(tmpbuf); info->dqi_free_entry = blk; mark_info_dirty(info->dqi_sb, info->dqi_type); return 0; out_buf: kfree(tmpbuf); return err; } /* Is the entry in the block free? */ int qtree_entry_unused(struct qtree_mem_dqinfo *info, char *disk) { int i; for (i = 0; i < info->dqi_entry_size; i++) if (disk[i]) return 0; return 1; } EXPORT_SYMBOL(qtree_entry_unused); /* Find space for dquot */ static uint find_free_dqentry(struct qtree_mem_dqinfo *info, struct dquot *dquot, int *err) { uint blk, i; struct qt_disk_dqdbheader *dh; char *buf = getdqbuf(info->dqi_usable_bs); char *ddquot; *err = 0; if (!buf) { *err = -ENOMEM; return 0; } dh = (struct qt_disk_dqdbheader *)buf; if (info->dqi_free_entry) { blk = info->dqi_free_entry; *err = read_blk(info, blk, buf); if (*err < 0) goto out_buf; } else { blk = get_free_dqblk(info); if ((int)blk < 0) { *err = blk; kfree(buf); return 0; } memset(buf, 0, info->dqi_usable_bs); /* This is enough as the block is already zeroed and the entry * list is empty... */ info->dqi_free_entry = blk; mark_info_dirty(dquot->dq_sb, dquot->dq_id.type); } /* Block will be full? */ if (le16_to_cpu(dh->dqdh_entries) + 1 >= qtree_dqstr_in_blk(info)) { *err = remove_free_dqentry(info, buf, blk); if (*err < 0) { quota_error(dquot->dq_sb, "Can't remove block (%u) " "from entry free list", blk); goto out_buf; } } le16_add_cpu(&dh->dqdh_entries, 1); /* Find free structure in block */ ddquot = buf + sizeof(struct qt_disk_dqdbheader); for (i = 0; i < qtree_dqstr_in_blk(info); i++) { if (qtree_entry_unused(info, ddquot)) break; ddquot += info->dqi_entry_size; } #ifdef __QUOTA_QT_PARANOIA if (i == qtree_dqstr_in_blk(info)) { quota_error(dquot->dq_sb, "Data block full but it shouldn't"); *err = -EIO; goto out_buf; } #endif *err = write_blk(info, blk, buf); if (*err < 0) { quota_error(dquot->dq_sb, "Can't write quota data block %u", blk); goto out_buf; } dquot->dq_off = (blk << info->dqi_blocksize_bits) + sizeof(struct qt_disk_dqdbheader) + i * info->dqi_entry_size; kfree(buf); return blk; out_buf: kfree(buf); return 0; } /* Insert reference to structure into the trie */ static int do_insert_tree(struct qtree_mem_dqinfo *info, struct dquot *dquot, uint *treeblk, int depth) { char *buf = getdqbuf(info->dqi_usable_bs); int ret = 0, newson = 0, newact = 0; __le32 *ref; uint newblk; if (!buf) return -ENOMEM; if (!*treeblk) { ret = get_free_dqblk(info); if (ret < 0) goto out_buf; *treeblk = ret; memset(buf, 0, info->dqi_usable_bs); newact = 1; } else { ret = read_blk(info, *treeblk, buf); if (ret < 0) { quota_error(dquot->dq_sb, "Can't read tree quota " "block %u", *treeblk); goto out_buf; } } ref = (__le32 *)buf; newblk = le32_to_cpu(ref[get_index(info, dquot->dq_id, depth)]); if (!newblk) newson = 1; if (depth == info->dqi_qtree_depth - 1) { #ifdef __QUOTA_QT_PARANOIA if (newblk) { quota_error(dquot->dq_sb, "Inserting already present " "quota entry (block %u)", le32_to_cpu(ref[get_index(info, dquot->dq_id, depth)])); ret = -EIO; goto out_buf; } #endif newblk = find_free_dqentry(info, dquot, &ret); } else { ret = do_insert_tree(info, dquot, &newblk, depth+1); } if (newson && ret >= 0) { ref[get_index(info, dquot->dq_id, depth)] = cpu_to_le32(newblk); ret = write_blk(info, *treeblk, buf); } else if (newact && ret < 0) { put_free_dqblk(info, buf, *treeblk); } out_buf: kfree(buf); return ret; } /* Wrapper for inserting quota structure into tree */ static inline int dq_insert_tree(struct qtree_mem_dqinfo *info, struct dquot *dquot) { int tmp = QT_TREEOFF; #ifdef __QUOTA_QT_PARANOIA if (info->dqi_blocks <= QT_TREEOFF) { quota_error(dquot->dq_sb, "Quota tree root isn't allocated!"); return -EIO; } #endif return do_insert_tree(info, dquot, &tmp, 0); } /* * We don't have to be afraid of deadlocks as we never have quotas on quota * files... */ int qtree_write_dquot(struct qtree_mem_dqinfo *info, struct dquot *dquot) { int type = dquot->dq_id.type; struct super_block *sb = dquot->dq_sb; ssize_t ret; char *ddquot = getdqbuf(info->dqi_entry_size); if (!ddquot) return -ENOMEM; /* dq_off is guarded by dqio_sem */ if (!dquot->dq_off) { ret = dq_insert_tree(info, dquot); if (ret < 0) { quota_error(sb, "Error %zd occurred while creating " "quota", ret); kfree(ddquot); return ret; } } spin_lock(&dquot->dq_dqb_lock); info->dqi_ops->mem2disk_dqblk(ddquot, dquot); spin_unlock(&dquot->dq_dqb_lock); ret = sb->s_op->quota_write(sb, type, ddquot, info->dqi_entry_size, dquot->dq_off); if (ret != info->dqi_entry_size) { quota_error(sb, "dquota write failed"); if (ret >= 0) ret = -ENOSPC; } else { ret = 0; } dqstats_inc(DQST_WRITES); kfree(ddquot); return ret; } EXPORT_SYMBOL(qtree_write_dquot); /* Free dquot entry in data block */ static int free_dqentry(struct qtree_mem_dqinfo *info, struct dquot *dquot, uint blk) { struct qt_disk_dqdbheader *dh; char *buf = getdqbuf(info->dqi_usable_bs); int ret = 0; if (!buf) return -ENOMEM; if (dquot->dq_off >> info->dqi_blocksize_bits != blk) { quota_error(dquot->dq_sb, "Quota structure has offset to " "other block (%u) than it should (%u)", blk, (uint)(dquot->dq_off >> info->dqi_blocksize_bits)); goto out_buf; } ret = read_blk(info, blk, buf); if (ret < 0) { quota_error(dquot->dq_sb, "Can't read quota data block %u", blk); goto out_buf; } dh = (struct qt_disk_dqdbheader *)buf; le16_add_cpu(&dh->dqdh_entries, -1); if (!le16_to_cpu(dh->dqdh_entries)) { /* Block got free? */ ret = remove_free_dqentry(info, buf, blk); if (ret >= 0) ret = put_free_dqblk(info, buf, blk); if (ret < 0) { quota_error(dquot->dq_sb, "Can't move quota data block " "(%u) to free list", blk); goto out_buf; } } else { memset(buf + (dquot->dq_off & ((1 << info->dqi_blocksize_bits) - 1)), 0, info->dqi_entry_size); if (le16_to_cpu(dh->dqdh_entries) == qtree_dqstr_in_blk(info) - 1) { /* Insert will write block itself */ ret = insert_free_dqentry(info, buf, blk); if (ret < 0) { quota_error(dquot->dq_sb, "Can't insert quota " "data block (%u) to free entry list", blk); goto out_buf; } } else { ret = write_blk(info, blk, buf); if (ret < 0) { quota_error(dquot->dq_sb, "Can't write quota " "data block %u", blk); goto out_buf; } } } dquot->dq_off = 0; /* Quota is now unattached */ out_buf: kfree(buf); return ret; } /* Remove reference to dquot from tree */ static int remove_tree(struct qtree_mem_dqinfo *info, struct dquot *dquot, uint *blk, int depth) { char *buf = getdqbuf(info->dqi_usable_bs); int ret = 0; uint newblk; __le32 *ref = (__le32 *)buf; if (!buf) return -ENOMEM; ret = read_blk(info, *blk, buf); if (ret < 0) { quota_error(dquot->dq_sb, "Can't read quota data block %u", *blk); goto out_buf; } newblk = le32_to_cpu(ref[get_index(info, dquot->dq_id, depth)]); if (depth == info->dqi_qtree_depth - 1) { ret = free_dqentry(info, dquot, newblk); newblk = 0; } else { ret = remove_tree(info, dquot, &newblk, depth+1); } if (ret >= 0 && !newblk) { int i; ref[get_index(info, dquot->dq_id, depth)] = cpu_to_le32(0); /* Block got empty? */ for (i = 0; i < (info->dqi_usable_bs >> 2) && !ref[i]; i++) ; /* Don't put the root block into the free block list */ if (i == (info->dqi_usable_bs >> 2) && *blk != QT_TREEOFF) { put_free_dqblk(info, buf, *blk); *blk = 0; } else { ret = write_blk(info, *blk, buf); if (ret < 0) quota_error(dquot->dq_sb, "Can't write quota tree block %u", *blk); } } out_buf: kfree(buf); return ret; } /* Delete dquot from tree */ int qtree_delete_dquot(struct qtree_mem_dqinfo *info, struct dquot *dquot) { uint tmp = QT_TREEOFF; if (!dquot->dq_off) /* Even not allocated? */ return 0; return remove_tree(info, dquot, &tmp, 0); } EXPORT_SYMBOL(qtree_delete_dquot); /* Find entry in block */ static loff_t find_block_dqentry(struct qtree_mem_dqinfo *info, struct dquot *dquot, uint blk) { char *buf = getdqbuf(info->dqi_usable_bs); loff_t ret = 0; int i; char *ddquot; if (!buf) return -ENOMEM; ret = read_blk(info, blk, buf); if (ret < 0) { quota_error(dquot->dq_sb, "Can't read quota tree " "block %u", blk); goto out_buf; } ddquot = buf + sizeof(struct qt_disk_dqdbheader); for (i = 0; i < qtree_dqstr_in_blk(info); i++) { if (info->dqi_ops->is_id(ddquot, dquot)) break; ddquot += info->dqi_entry_size; } if (i == qtree_dqstr_in_blk(info)) { quota_error(dquot->dq_sb, "Quota for id %u referenced but not present", from_kqid(&init_user_ns, dquot->dq_id)); ret = -EIO; goto out_buf; } else { ret = (blk << info->dqi_blocksize_bits) + sizeof(struct qt_disk_dqdbheader) + i * info->dqi_entry_size; } out_buf: kfree(buf); return ret; } /* Find entry for given id in the tree */ static loff_t find_tree_dqentry(struct qtree_mem_dqinfo *info, struct dquot *dquot, uint blk, int depth) { char *buf = getdqbuf(info->dqi_usable_bs); loff_t ret = 0; __le32 *ref = (__le32 *)buf; if (!buf) return -ENOMEM; ret = read_blk(info, blk, buf); if (ret < 0) { quota_error(dquot->dq_sb, "Can't read quota tree block %u", blk); goto out_buf; } ret = 0; blk = le32_to_cpu(ref[get_index(info, dquot->dq_id, depth)]); if (!blk) /* No reference? */ goto out_buf; if (depth < info->dqi_qtree_depth - 1) ret = find_tree_dqentry(info, dquot, blk, depth+1); else ret = find_block_dqentry(info, dquot, blk); out_buf: kfree(buf); return ret; } /* Find entry for given id in the tree - wrapper function */ static inline loff_t find_dqentry(struct qtree_mem_dqinfo *info, struct dquot *dquot) { return find_tree_dqentry(info, dquot, QT_TREEOFF, 0); } int qtree_read_dquot(struct qtree_mem_dqinfo *info, struct dquot *dquot) { int type = dquot->dq_id.type; struct super_block *sb = dquot->dq_sb; loff_t offset; char *ddquot; int ret = 0; #ifdef __QUOTA_QT_PARANOIA /* Invalidated quota? */ if (!sb_dqopt(dquot->dq_sb)->files[type]) { quota_error(sb, "Quota invalidated while reading!"); return -EIO; } #endif /* Do we know offset of the dquot entry in the quota file? */ if (!dquot->dq_off) { offset = find_dqentry(info, dquot); if (offset <= 0) { /* Entry not present? */ if (offset < 0) quota_error(sb,"Can't read quota structure " "for id %u", from_kqid(&init_user_ns, dquot->dq_id)); dquot->dq_off = 0; set_bit(DQ_FAKE_B, &dquot->dq_flags); memset(&dquot->dq_dqb, 0, sizeof(struct mem_dqblk)); ret = offset; goto out; } dquot->dq_off = offset; } ddquot = getdqbuf(info->dqi_entry_size); if (!ddquot) return -ENOMEM; ret = sb->s_op->quota_read(sb, type, ddquot, info->dqi_entry_size, dquot->dq_off); if (ret != info->dqi_entry_size) { if (ret >= 0) ret = -EIO; quota_error(sb, "Error while reading quota structure for id %u", from_kqid(&init_user_ns, dquot->dq_id)); set_bit(DQ_FAKE_B, &dquot->dq_flags); memset(&dquot->dq_dqb, 0, sizeof(struct mem_dqblk)); kfree(ddquot); goto out; } spin_lock(&dquot->dq_dqb_lock); info->dqi_ops->disk2mem_dqblk(dquot, ddquot); if (!dquot->dq_dqb.dqb_bhardlimit && !dquot->dq_dqb.dqb_bsoftlimit && !dquot->dq_dqb.dqb_ihardlimit && !dquot->dq_dqb.dqb_isoftlimit) set_bit(DQ_FAKE_B, &dquot->dq_flags); spin_unlock(&dquot->dq_dqb_lock); kfree(ddquot); out: dqstats_inc(DQST_READS); return ret; } EXPORT_SYMBOL(qtree_read_dquot); /* Check whether dquot should not be deleted. We know we are * the only one operating on dquot (thanks to dq_lock) */ int qtree_release_dquot(struct qtree_mem_dqinfo *info, struct dquot *dquot) { if (test_bit(DQ_FAKE_B, &dquot->dq_flags) && !(dquot->dq_dqb.dqb_curinodes | dquot->dq_dqb.dqb_curspace)) return qtree_delete_dquot(info, dquot); return 0; } EXPORT_SYMBOL(qtree_release_dquot); static int find_next_id(struct qtree_mem_dqinfo *info, qid_t *id, unsigned int blk, int depth) { char *buf = getdqbuf(info->dqi_usable_bs); __le32 *ref = (__le32 *)buf; ssize_t ret; unsigned int epb = info->dqi_usable_bs >> 2; unsigned int level_inc = 1; int i; if (!buf) return -ENOMEM; for (i = depth; i < info->dqi_qtree_depth - 1; i++) level_inc *= epb; ret = read_blk(info, blk, buf); if (ret < 0) { quota_error(info->dqi_sb, "Can't read quota tree block %u", blk); goto out_buf; } for (i = __get_index(info, *id, depth); i < epb; i++) { if (ref[i] == cpu_to_le32(0)) { *id += level_inc; continue; } if (depth == info->dqi_qtree_depth - 1) { ret = 0; goto out_buf; } ret = find_next_id(info, id, le32_to_cpu(ref[i]), depth + 1); if (ret != -ENOENT) break; } if (i == epb) { ret = -ENOENT; goto out_buf; } out_buf: kfree(buf); return ret; } int qtree_get_next_id(struct qtree_mem_dqinfo *info, struct kqid *qid) { qid_t id = from_kqid(&init_user_ns, *qid); int ret; ret = find_next_id(info, &id, QT_TREEOFF, 0); if (ret < 0) return ret; *qid = make_kqid(&init_user_ns, qid->type, id); return 0; } EXPORT_SYMBOL(qtree_get_next_id);