/* * 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 typedef char *dqbuf_t; 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; } /* Number of entries in one blocks */ static inline 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 dqbuf_t getdqbuf(size_t size) { dqbuf_t buf = kmalloc(size, GFP_NOFS); if (!buf) printk(KERN_WARNING "VFS: Not enough memory for quota buffers.\n"); return buf; } static inline void freedqbuf(dqbuf_t buf) { kfree(buf); } static inline ssize_t read_blk(struct qtree_mem_dqinfo *info, uint blk, dqbuf_t 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, (char *)buf, info->dqi_usable_bs, blk << info->dqi_blocksize_bits); } static inline ssize_t write_blk(struct qtree_mem_dqinfo *info, uint blk, dqbuf_t buf) { struct super_block *sb = info->dqi_sb; return sb->s_op->quota_write(sb, info->dqi_type, (char *)buf, info->dqi_usable_bs, blk << info->dqi_blocksize_bits); } /* Remove empty block from list and return it */ static int get_free_dqblk(struct qtree_mem_dqinfo *info) { dqbuf_t 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: freedqbuf(buf); return ret; } /* Insert empty block to the list */ static int put_free_dqblk(struct qtree_mem_dqinfo *info, dqbuf_t 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, dqbuf_t buf, uint blk) { dqbuf_t 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); } freedqbuf(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) printk(KERN_ERR "VFS: Can't write block (%u) with free entries.\n", blk); return 0; out_buf: freedqbuf(tmpbuf); return err; } /* Insert given block to the beginning of list with free entries */ static int insert_free_dqentry(struct qtree_mem_dqinfo *info, dqbuf_t buf, uint blk) { dqbuf_t 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; } freedqbuf(tmpbuf); info->dqi_free_entry = blk; mark_info_dirty(info->dqi_sb, info->dqi_type); return 0; out_buf: freedqbuf(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; dqbuf_t 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; freedqbuf(buf); return 0; } memset(buf, 0, info->dqi_usable_bs); /* This is enough as block is already zeroed and entry list is empty... */ info->dqi_free_entry = blk; mark_info_dirty(dquot->dq_sb, dquot->dq_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) { printk(KERN_ERR "VFS: find_free_dqentry(): Can't " "remove block (%u) from entry free list.\n", blk); goto out_buf; } } le16_add_cpu(&dh->dqdh_entries, 1); /* Find free structure in block */ for (i = 0, ddquot = ((char *)buf) + sizeof(struct qt_disk_dqdbheader); i < qtree_dqstr_in_blk(info) && !qtree_entry_unused(info, ddquot); i++, ddquot += info->dqi_entry_size); #ifdef __QUOTA_QT_PARANOIA if (i == qtree_dqstr_in_blk(info)) { printk(KERN_ERR "VFS: find_free_dqentry(): Data block full " "but it shouldn't.\n"); *err = -EIO; goto out_buf; } #endif *err = write_blk(info, blk, buf); if (*err < 0) { printk(KERN_ERR "VFS: find_free_dqentry(): Can't write quota " "data block %u.\n", blk); goto out_buf; } dquot->dq_off = (blk << info->dqi_blocksize_bits) + sizeof(struct qt_disk_dqdbheader) + i * info->dqi_entry_size; freedqbuf(buf); return blk; out_buf: freedqbuf(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) { dqbuf_t 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) { printk(KERN_ERR "VFS: Can't read tree quota block " "%u.\n", *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) { printk(KERN_ERR "VFS: Inserting already present quota " "entry (block %u).\n", 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: freedqbuf(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; 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_type; struct super_block *sb = dquot->dq_sb; ssize_t ret; dqbuf_t ddquot = getdqbuf(info->dqi_entry_size); if (!ddquot) return -ENOMEM; /* dq_off is guarded by dqio_mutex */ if (!dquot->dq_off) { ret = dq_insert_tree(info, dquot); if (ret < 0) { printk(KERN_ERR "VFS: Error %zd occurred while " "creating quota.\n", ret); freedqbuf(ddquot); return ret; } } spin_lock(&dq_data_lock); info->dqi_ops->mem2disk_dqblk(ddquot, dquot); spin_unlock(&dq_data_lock); ret = sb->s_op->quota_write(sb, type, (char *)ddquot, info->dqi_entry_size, dquot->dq_off); if (ret != info->dqi_entry_size) { printk(KERN_WARNING "VFS: dquota write failed on dev %s\n", sb->s_id); if (ret >= 0) ret = -ENOSPC; } else { ret = 0; } dqstats.writes++; freedqbuf(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; dqbuf_t buf = getdqbuf(info->dqi_usable_bs); int ret = 0; if (!buf) return -ENOMEM; if (dquot->dq_off >> info->dqi_blocksize_bits != blk) { printk(KERN_ERR "VFS: Quota structure has offset to other " "block (%u) than it should (%u).\n", blk, (uint)(dquot->dq_off >> info->dqi_blocksize_bits)); goto out_buf; } ret = read_blk(info, blk, buf); if (ret < 0) { printk(KERN_ERR "VFS: Can't read quota data block %u\n", 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) { printk(KERN_ERR "VFS: Can't move quota data block (%u) " "to free list.\n", 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) { printk(KERN_ERR "VFS: Can't insert quota data " "block (%u) to free entry list.\n", blk); goto out_buf; } } else { ret = write_blk(info, blk, buf); if (ret < 0) { printk(KERN_ERR "VFS: Can't write quota data " "block %u\n", blk); goto out_buf; } } } dquot->dq_off = 0; /* Quota is now unattached */ out_buf: freedqbuf(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) { dqbuf_t 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) { printk(KERN_ERR "VFS: Can't read quota data block %u\n", *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) printk(KERN_ERR "VFS: Can't write quota tree " "block %u.\n", *blk); } } out_buf: freedqbuf(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) { dqbuf_t 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) { printk(KERN_ERR "VFS: Can't read quota tree block %u.\n", blk); goto out_buf; } for (i = 0, ddquot = ((char *)buf) + sizeof(struct qt_disk_dqdbheader); i < qtree_dqstr_in_blk(info) && !info->dqi_ops->is_id(ddquot, dquot); i++, ddquot += info->dqi_entry_size); if (i == qtree_dqstr_in_blk(info)) { printk(KERN_ERR "VFS: Quota for id %u referenced " "but not present.\n", 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: freedqbuf(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) { dqbuf_t 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) { printk(KERN_ERR "VFS: Can't read quota tree block %u.\n", 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: freedqbuf(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_type; struct super_block *sb = dquot->dq_sb; loff_t offset; dqbuf_t ddquot; int ret = 0; #ifdef __QUOTA_QT_PARANOIA /* Invalidated quota? */ if (!sb_dqopt(dquot->dq_sb)->files[type]) { printk(KERN_ERR "VFS: Quota invalidated while reading!\n"); 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) printk(KERN_ERR "VFS: Can't read quota " "structure for id %u.\n", 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, (char *)ddquot, info->dqi_entry_size, dquot->dq_off); if (ret != info->dqi_entry_size) { if (ret >= 0) ret = -EIO; printk(KERN_ERR "VFS: Error while reading quota " "structure for id %u.\n", dquot->dq_id); set_bit(DQ_FAKE_B, &dquot->dq_flags); memset(&dquot->dq_dqb, 0, sizeof(struct mem_dqblk)); freedqbuf(ddquot); goto out; } spin_lock(&dq_data_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(&dq_data_lock); freedqbuf(ddquot); out: dqstats.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);