From bdcfd44fb5b5fb8fd660e7f93f1095c507481024 Mon Sep 17 00:00:00 2001 From: =?UTF-8?q?Andr=C3=A9=20Fabian=20Silva=20Delgado?= Date: Sat, 16 Apr 2016 15:30:54 -0300 Subject: Linux-libre 4.5.1-gnu --- fs/aufs/dynop.c | 356 ++++++++++++++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 356 insertions(+) create mode 100644 fs/aufs/dynop.c (limited to 'fs/aufs/dynop.c') diff --git a/fs/aufs/dynop.c b/fs/aufs/dynop.c new file mode 100644 index 000000000..53a8b55d8 --- /dev/null +++ b/fs/aufs/dynop.c @@ -0,0 +1,356 @@ +/* + * Copyright (C) 2010-2016 Junjiro R. Okajima + */ + +/* + * dynamically customizable operations for regular files + */ + +#include "aufs.h" + +#define DyPrSym(key) AuDbgSym(key->dk_op.dy_hop) + +/* + * How large will these lists be? + * Usually just a few elements, 20-30 at most for each, I guess. + */ +static struct au_splhead dynop[AuDyLast]; + +static struct au_dykey *dy_gfind_get(struct au_splhead *spl, const void *h_op) +{ + struct au_dykey *key, *tmp; + struct list_head *head; + + key = NULL; + head = &spl->head; + rcu_read_lock(); + list_for_each_entry_rcu(tmp, head, dk_list) + if (tmp->dk_op.dy_hop == h_op) { + key = tmp; + kref_get(&key->dk_kref); + break; + } + rcu_read_unlock(); + + return key; +} + +static struct au_dykey *dy_bradd(struct au_branch *br, struct au_dykey *key) +{ + struct au_dykey **k, *found; + const void *h_op = key->dk_op.dy_hop; + int i; + + found = NULL; + k = br->br_dykey; + for (i = 0; i < AuBrDynOp; i++) + if (k[i]) { + if (k[i]->dk_op.dy_hop == h_op) { + found = k[i]; + break; + } + } else + break; + if (!found) { + spin_lock(&br->br_dykey_lock); + for (; i < AuBrDynOp; i++) + if (k[i]) { + if (k[i]->dk_op.dy_hop == h_op) { + found = k[i]; + break; + } + } else { + k[i] = key; + break; + } + spin_unlock(&br->br_dykey_lock); + BUG_ON(i == AuBrDynOp); /* expand the array */ + } + + return found; +} + +/* kref_get() if @key is already added */ +static struct au_dykey *dy_gadd(struct au_splhead *spl, struct au_dykey *key) +{ + struct au_dykey *tmp, *found; + struct list_head *head; + const void *h_op = key->dk_op.dy_hop; + + found = NULL; + head = &spl->head; + spin_lock(&spl->spin); + list_for_each_entry(tmp, head, dk_list) + if (tmp->dk_op.dy_hop == h_op) { + kref_get(&tmp->dk_kref); + found = tmp; + break; + } + if (!found) + list_add_rcu(&key->dk_list, head); + spin_unlock(&spl->spin); + + if (!found) + DyPrSym(key); + return found; +} + +static void dy_free_rcu(struct rcu_head *rcu) +{ + struct au_dykey *key; + + key = container_of(rcu, struct au_dykey, dk_rcu); + DyPrSym(key); + kfree(key); +} + +static void dy_free(struct kref *kref) +{ + struct au_dykey *key; + struct au_splhead *spl; + + key = container_of(kref, struct au_dykey, dk_kref); + spl = dynop + key->dk_op.dy_type; + au_spl_del_rcu(&key->dk_list, spl); + call_rcu(&key->dk_rcu, dy_free_rcu); +} + +void au_dy_put(struct au_dykey *key) +{ + kref_put(&key->dk_kref, dy_free); +} + +/* ---------------------------------------------------------------------- */ + +#define DyDbgSize(cnt, op) AuDebugOn(cnt != sizeof(op)/sizeof(void *)) + +#ifdef CONFIG_AUFS_DEBUG +#define DyDbgDeclare(cnt) unsigned int cnt = 0 +#define DyDbgInc(cnt) do { cnt++; } while (0) +#else +#define DyDbgDeclare(cnt) do {} while (0) +#define DyDbgInc(cnt) do {} while (0) +#endif + +#define DySet(func, dst, src, h_op, h_sb) do { \ + DyDbgInc(cnt); \ + if (h_op->func) { \ + if (src.func) \ + dst.func = src.func; \ + else \ + AuDbg("%s %s\n", au_sbtype(h_sb), #func); \ + } \ +} while (0) + +#define DySetForce(func, dst, src) do { \ + AuDebugOn(!src.func); \ + DyDbgInc(cnt); \ + dst.func = src.func; \ +} while (0) + +#define DySetAop(func) \ + DySet(func, dyaop->da_op, aufs_aop, h_aop, h_sb) +#define DySetAopForce(func) \ + DySetForce(func, dyaop->da_op, aufs_aop) + +static void dy_aop(struct au_dykey *key, const void *h_op, + struct super_block *h_sb __maybe_unused) +{ + struct au_dyaop *dyaop = (void *)key; + const struct address_space_operations *h_aop = h_op; + DyDbgDeclare(cnt); + + AuDbg("%s\n", au_sbtype(h_sb)); + + DySetAop(writepage); + DySetAopForce(readpage); /* force */ + DySetAop(writepages); + DySetAop(set_page_dirty); + DySetAop(readpages); + DySetAop(write_begin); + DySetAop(write_end); + DySetAop(bmap); + DySetAop(invalidatepage); + DySetAop(releasepage); + DySetAop(freepage); + /* this one will be changed according to an aufs mount option */ + DySetAop(direct_IO); + DySetAop(migratepage); + DySetAop(launder_page); + DySetAop(is_partially_uptodate); + DySetAop(is_dirty_writeback); + DySetAop(error_remove_page); + DySetAop(swap_activate); + DySetAop(swap_deactivate); + + DyDbgSize(cnt, *h_aop); +} + +/* ---------------------------------------------------------------------- */ + +static void dy_bug(struct kref *kref) +{ + BUG(); +} + +static struct au_dykey *dy_get(struct au_dynop *op, struct au_branch *br) +{ + struct au_dykey *key, *old; + struct au_splhead *spl; + struct op { + unsigned int sz; + void (*set)(struct au_dykey *key, const void *h_op, + struct super_block *h_sb __maybe_unused); + }; + static const struct op a[] = { + [AuDy_AOP] = { + .sz = sizeof(struct au_dyaop), + .set = dy_aop + } + }; + const struct op *p; + + spl = dynop + op->dy_type; + key = dy_gfind_get(spl, op->dy_hop); + if (key) + goto out_add; /* success */ + + p = a + op->dy_type; + key = kzalloc(p->sz, GFP_NOFS); + if (unlikely(!key)) { + key = ERR_PTR(-ENOMEM); + goto out; + } + + key->dk_op.dy_hop = op->dy_hop; + kref_init(&key->dk_kref); + p->set(key, op->dy_hop, au_br_sb(br)); + old = dy_gadd(spl, key); + if (old) { + kfree(key); + key = old; + } + +out_add: + old = dy_bradd(br, key); + if (old) + /* its ref-count should never be zero here */ + kref_put(&key->dk_kref, dy_bug); +out: + return key; +} + +/* ---------------------------------------------------------------------- */ +/* + * Aufs prohibits O_DIRECT by defaut even if the branch supports it. + * This behaviour is necessary to return an error from open(O_DIRECT) instead + * of the succeeding I/O. The dio mount option enables O_DIRECT and makes + * open(O_DIRECT) always succeed, but the succeeding I/O may return an error. + * See the aufs manual in detail. + */ +static void dy_adx(struct au_dyaop *dyaop, int do_dx) +{ + if (!do_dx) + dyaop->da_op.direct_IO = NULL; + else + dyaop->da_op.direct_IO = aufs_aop.direct_IO; +} + +static struct au_dyaop *dy_aget(struct au_branch *br, + const struct address_space_operations *h_aop, + int do_dx) +{ + struct au_dyaop *dyaop; + struct au_dynop op; + + op.dy_type = AuDy_AOP; + op.dy_haop = h_aop; + dyaop = (void *)dy_get(&op, br); + if (IS_ERR(dyaop)) + goto out; + dy_adx(dyaop, do_dx); + +out: + return dyaop; +} + +int au_dy_iaop(struct inode *inode, aufs_bindex_t bindex, + struct inode *h_inode) +{ + int err, do_dx; + struct super_block *sb; + struct au_branch *br; + struct au_dyaop *dyaop; + + AuDebugOn(!S_ISREG(h_inode->i_mode)); + IiMustWriteLock(inode); + + sb = inode->i_sb; + br = au_sbr(sb, bindex); + do_dx = !!au_opt_test(au_mntflags(sb), DIO); + dyaop = dy_aget(br, h_inode->i_mapping->a_ops, do_dx); + err = PTR_ERR(dyaop); + if (IS_ERR(dyaop)) + /* unnecessary to call dy_fput() */ + goto out; + + err = 0; + inode->i_mapping->a_ops = &dyaop->da_op; + +out: + return err; +} + +/* + * Is it safe to replace a_ops during the inode/file is in operation? + * Yes, I hope so. + */ +int au_dy_irefresh(struct inode *inode) +{ + int err; + aufs_bindex_t bstart; + struct inode *h_inode; + + err = 0; + if (S_ISREG(inode->i_mode)) { + bstart = au_ibstart(inode); + h_inode = au_h_iptr(inode, bstart); + err = au_dy_iaop(inode, bstart, h_inode); + } + return err; +} + +void au_dy_arefresh(int do_dx) +{ + struct au_splhead *spl; + struct list_head *head; + struct au_dykey *key; + + spl = dynop + AuDy_AOP; + head = &spl->head; + spin_lock(&spl->spin); + list_for_each_entry(key, head, dk_list) + dy_adx((void *)key, do_dx); + spin_unlock(&spl->spin); +} + +/* ---------------------------------------------------------------------- */ + +void __init au_dy_init(void) +{ + int i; + + /* make sure that 'struct au_dykey *' can be any type */ + BUILD_BUG_ON(offsetof(struct au_dyaop, da_key)); + + for (i = 0; i < AuDyLast; i++) + au_spl_init(dynop + i); +} + +void au_dy_fin(void) +{ + int i; + + for (i = 0; i < AuDyLast; i++) + WARN_ON(!list_empty(&dynop[i].head)); +} -- cgit v1.2.3