diff options
Diffstat (limited to 'fs/logfs/inode.c')
-rw-r--r-- | fs/logfs/inode.c | 428 |
1 files changed, 0 insertions, 428 deletions
diff --git a/fs/logfs/inode.c b/fs/logfs/inode.c deleted file mode 100644 index f440a1525da8..000000000000 --- a/fs/logfs/inode.c +++ /dev/null @@ -1,428 +0,0 @@ -/* - * fs/logfs/inode.c - inode handling code - * - * As should be obvious for Linux kernel code, license is GPLv2 - * - * Copyright (c) 2005-2008 Joern Engel <joern@logfs.org> - */ -#include "logfs.h" -#include <linux/slab.h> -#include <linux/writeback.h> -#include <linux/backing-dev.h> - -/* - * How soon to reuse old inode numbers? LogFS doesn't store deleted inodes - * on the medium. It therefore also lacks a method to store the previous - * generation number for deleted inodes. Instead a single generation number - * is stored which will be used for new inodes. Being just a 32bit counter, - * this can obvious wrap relatively quickly. So we only reuse inodes if we - * know that a fair number of inodes can be created before we have to increment - * the generation again - effectively adding some bits to the counter. - * But being too aggressive here means we keep a very large and very sparse - * inode file, wasting space on indirect blocks. - * So what is a good value? Beats me. 64k seems moderately bad on both - * fronts, so let's use that for now... - * - * NFS sucks, as everyone already knows. - */ -#define INOS_PER_WRAP (0x10000) - -/* - * Logfs' requirement to read inodes for garbage collection makes life a bit - * harder. GC may have to read inodes that are in I_FREEING state, when they - * are being written out - and waiting for GC to make progress, naturally. - * - * So we cannot just call iget() or some variant of it, but first have to check - * whether the inode in question might be in I_FREEING state. Therefore we - * maintain our own per-sb list of "almost deleted" inodes and check against - * that list first. Normally this should be at most 1-2 entries long. - * - * Also, inodes have logfs-specific reference counting on top of what the vfs - * does. When .destroy_inode is called, normally the reference count will drop - * to zero and the inode gets deleted. But if GC accessed the inode, its - * refcount will remain nonzero and final deletion will have to wait. - * - * As a result we have two sets of functions to get/put inodes: - * logfs_safe_iget/logfs_safe_iput - safe to call from GC context - * logfs_iget/iput - normal version - */ -static struct kmem_cache *logfs_inode_cache; - -static DEFINE_SPINLOCK(logfs_inode_lock); - -static void logfs_inode_setops(struct inode *inode) -{ - switch (inode->i_mode & S_IFMT) { - case S_IFDIR: - inode->i_op = &logfs_dir_iops; - inode->i_fop = &logfs_dir_fops; - inode->i_mapping->a_ops = &logfs_reg_aops; - break; - case S_IFREG: - inode->i_op = &logfs_reg_iops; - inode->i_fop = &logfs_reg_fops; - inode->i_mapping->a_ops = &logfs_reg_aops; - break; - case S_IFLNK: - inode->i_op = &page_symlink_inode_operations; - inode_nohighmem(inode); - inode->i_mapping->a_ops = &logfs_reg_aops; - break; - case S_IFSOCK: /* fall through */ - case S_IFBLK: /* fall through */ - case S_IFCHR: /* fall through */ - case S_IFIFO: - init_special_inode(inode, inode->i_mode, inode->i_rdev); - break; - default: - BUG(); - } -} - -static struct inode *__logfs_iget(struct super_block *sb, ino_t ino) -{ - struct inode *inode = iget_locked(sb, ino); - int err; - - if (!inode) - return ERR_PTR(-ENOMEM); - if (!(inode->i_state & I_NEW)) - return inode; - - err = logfs_read_inode(inode); - if (err || inode->i_nlink == 0) { - /* inode->i_nlink == 0 can be true when called from - * block validator */ - /* set i_nlink to 0 to prevent caching */ - clear_nlink(inode); - logfs_inode(inode)->li_flags |= LOGFS_IF_ZOMBIE; - iget_failed(inode); - if (!err) - err = -ENOENT; - return ERR_PTR(err); - } - - logfs_inode_setops(inode); - unlock_new_inode(inode); - return inode; -} - -struct inode *logfs_iget(struct super_block *sb, ino_t ino) -{ - BUG_ON(ino == LOGFS_INO_MASTER); - BUG_ON(ino == LOGFS_INO_SEGFILE); - return __logfs_iget(sb, ino); -} - -/* - * is_cached is set to 1 if we hand out a cached inode, 0 otherwise. - * this allows logfs_iput to do the right thing later - */ -struct inode *logfs_safe_iget(struct super_block *sb, ino_t ino, int *is_cached) -{ - struct logfs_super *super = logfs_super(sb); - struct logfs_inode *li; - - if (ino == LOGFS_INO_MASTER) - return super->s_master_inode; - if (ino == LOGFS_INO_SEGFILE) - return super->s_segfile_inode; - - spin_lock(&logfs_inode_lock); - list_for_each_entry(li, &super->s_freeing_list, li_freeing_list) - if (li->vfs_inode.i_ino == ino) { - li->li_refcount++; - spin_unlock(&logfs_inode_lock); - *is_cached = 1; - return &li->vfs_inode; - } - spin_unlock(&logfs_inode_lock); - - *is_cached = 0; - return __logfs_iget(sb, ino); -} - -static void logfs_i_callback(struct rcu_head *head) -{ - struct inode *inode = container_of(head, struct inode, i_rcu); - kmem_cache_free(logfs_inode_cache, logfs_inode(inode)); -} - -static void __logfs_destroy_inode(struct inode *inode) -{ - struct logfs_inode *li = logfs_inode(inode); - - BUG_ON(li->li_block); - list_del(&li->li_freeing_list); - call_rcu(&inode->i_rcu, logfs_i_callback); -} - -static void __logfs_destroy_meta_inode(struct inode *inode) -{ - struct logfs_inode *li = logfs_inode(inode); - BUG_ON(li->li_block); - call_rcu(&inode->i_rcu, logfs_i_callback); -} - -static void logfs_destroy_inode(struct inode *inode) -{ - struct logfs_inode *li = logfs_inode(inode); - - if (inode->i_ino < LOGFS_RESERVED_INOS) { - /* - * The reserved inodes are never destroyed unless we are in - * unmont path. - */ - __logfs_destroy_meta_inode(inode); - return; - } - - BUG_ON(list_empty(&li->li_freeing_list)); - spin_lock(&logfs_inode_lock); - li->li_refcount--; - if (li->li_refcount == 0) - __logfs_destroy_inode(inode); - spin_unlock(&logfs_inode_lock); -} - -void logfs_safe_iput(struct inode *inode, int is_cached) -{ - if (inode->i_ino == LOGFS_INO_MASTER) - return; - if (inode->i_ino == LOGFS_INO_SEGFILE) - return; - - if (is_cached) { - logfs_destroy_inode(inode); - return; - } - - iput(inode); -} - -static void logfs_init_inode(struct super_block *sb, struct inode *inode) -{ - struct logfs_inode *li = logfs_inode(inode); - int i; - - li->li_flags = 0; - li->li_height = 0; - li->li_used_bytes = 0; - li->li_block = NULL; - i_uid_write(inode, 0); - i_gid_write(inode, 0); - inode->i_size = 0; - inode->i_blocks = 0; - inode->i_ctime = current_time(inode); - inode->i_mtime = current_time(inode); - li->li_refcount = 1; - INIT_LIST_HEAD(&li->li_freeing_list); - - for (i = 0; i < LOGFS_EMBEDDED_FIELDS; i++) - li->li_data[i] = 0; - - return; -} - -static struct inode *logfs_alloc_inode(struct super_block *sb) -{ - struct logfs_inode *li; - - li = kmem_cache_alloc(logfs_inode_cache, GFP_NOFS); - if (!li) - return NULL; - logfs_init_inode(sb, &li->vfs_inode); - return &li->vfs_inode; -} - -/* - * In logfs inodes are written to an inode file. The inode file, like any - * other file, is managed with a inode. The inode file's inode, aka master - * inode, requires special handling in several respects. First, it cannot be - * written to the inode file, so it is stored in the journal instead. - * - * Secondly, this inode cannot be written back and destroyed before all other - * inodes have been written. The ordering is important. Linux' VFS is happily - * unaware of the ordering constraint and would ordinarily destroy the master - * inode at umount time while other inodes are still in use and dirty. Not - * good. - * - * So logfs makes sure the master inode is not written until all other inodes - * have been destroyed. Sadly, this method has another side-effect. The VFS - * will notice one remaining inode and print a frightening warning message. - * Worse, it is impossible to judge whether such a warning was caused by the - * master inode or any other inodes have leaked as well. - * - * Our attempt of solving this is with logfs_new_meta_inode() below. Its - * purpose is to create a new inode that will not trigger the warning if such - * an inode is still in use. An ugly hack, no doubt. Suggections for - * improvement are welcome. - * - * AV: that's what ->put_super() is for... - */ -struct inode *logfs_new_meta_inode(struct super_block *sb, u64 ino) -{ - struct inode *inode; - - inode = new_inode(sb); - if (!inode) - return ERR_PTR(-ENOMEM); - - inode->i_mode = S_IFREG; - inode->i_ino = ino; - inode->i_data.a_ops = &logfs_reg_aops; - mapping_set_gfp_mask(&inode->i_data, GFP_NOFS); - - return inode; -} - -struct inode *logfs_read_meta_inode(struct super_block *sb, u64 ino) -{ - struct inode *inode; - int err; - - inode = logfs_new_meta_inode(sb, ino); - if (IS_ERR(inode)) - return inode; - - err = logfs_read_inode(inode); - if (err) { - iput(inode); - return ERR_PTR(err); - } - logfs_inode_setops(inode); - return inode; -} - -static int logfs_write_inode(struct inode *inode, struct writeback_control *wbc) -{ - int ret; - long flags = WF_LOCK; - - /* Can only happen if creat() failed. Safe to skip. */ - if (logfs_inode(inode)->li_flags & LOGFS_IF_STILLBORN) - return 0; - - ret = __logfs_write_inode(inode, NULL, flags); - LOGFS_BUG_ON(ret, inode->i_sb); - return ret; -} - -/* called with inode->i_lock held */ -static int logfs_drop_inode(struct inode *inode) -{ - struct logfs_super *super = logfs_super(inode->i_sb); - struct logfs_inode *li = logfs_inode(inode); - - spin_lock(&logfs_inode_lock); - list_move(&li->li_freeing_list, &super->s_freeing_list); - spin_unlock(&logfs_inode_lock); - return generic_drop_inode(inode); -} - -static void logfs_set_ino_generation(struct super_block *sb, - struct inode *inode) -{ - struct logfs_super *super = logfs_super(sb); - u64 ino; - - mutex_lock(&super->s_journal_mutex); - ino = logfs_seek_hole(super->s_master_inode, super->s_last_ino + 1); - super->s_last_ino = ino; - super->s_inos_till_wrap--; - if (super->s_inos_till_wrap < 0) { - super->s_last_ino = LOGFS_RESERVED_INOS; - super->s_generation++; - super->s_inos_till_wrap = INOS_PER_WRAP; - } - inode->i_ino = ino; - inode->i_generation = super->s_generation; - mutex_unlock(&super->s_journal_mutex); -} - -struct inode *logfs_new_inode(struct inode *dir, umode_t mode) -{ - struct super_block *sb = dir->i_sb; - struct inode *inode; - - inode = new_inode(sb); - if (!inode) - return ERR_PTR(-ENOMEM); - - logfs_init_inode(sb, inode); - - /* inherit parent flags */ - logfs_inode(inode)->li_flags |= - logfs_inode(dir)->li_flags & LOGFS_FL_INHERITED; - - inode->i_mode = mode; - logfs_set_ino_generation(sb, inode); - - inode_init_owner(inode, dir, mode); - logfs_inode_setops(inode); - insert_inode_hash(inode); - - return inode; -} - -static void logfs_init_once(void *_li) -{ - struct logfs_inode *li = _li; - int i; - - li->li_flags = 0; - li->li_used_bytes = 0; - li->li_refcount = 1; - for (i = 0; i < LOGFS_EMBEDDED_FIELDS; i++) - li->li_data[i] = 0; - inode_init_once(&li->vfs_inode); -} - -static int logfs_sync_fs(struct super_block *sb, int wait) -{ - logfs_get_wblocks(sb, NULL, WF_LOCK); - logfs_write_anchor(sb); - logfs_put_wblocks(sb, NULL, WF_LOCK); - return 0; -} - -static void logfs_put_super(struct super_block *sb) -{ - struct logfs_super *super = logfs_super(sb); - /* kill the meta-inodes */ - iput(super->s_segfile_inode); - iput(super->s_master_inode); - iput(super->s_mapping_inode); -} - -const struct super_operations logfs_super_operations = { - .alloc_inode = logfs_alloc_inode, - .destroy_inode = logfs_destroy_inode, - .evict_inode = logfs_evict_inode, - .drop_inode = logfs_drop_inode, - .put_super = logfs_put_super, - .write_inode = logfs_write_inode, - .statfs = logfs_statfs, - .sync_fs = logfs_sync_fs, -}; - -int logfs_init_inode_cache(void) -{ - logfs_inode_cache = kmem_cache_create("logfs_inode_cache", - sizeof(struct logfs_inode), 0, - SLAB_RECLAIM_ACCOUNT|SLAB_ACCOUNT, - logfs_init_once); - if (!logfs_inode_cache) - return -ENOMEM; - return 0; -} - -void logfs_destroy_inode_cache(void) -{ - /* - * Make sure all delayed rcu free inodes are flushed before we - * destroy cache. - */ - rcu_barrier(); - kmem_cache_destroy(logfs_inode_cache); -} |