From: Junjiro Okajima <hooanon05@xxxxxxxxxxx>
initial commit
pseudo-link is a logical hardlink over branches or different filesystems.
Signed-off-by: Junjiro Okajima <hooanon05@xxxxxxxxxxx>
---
fs/aufs/plink.c | 344 +++++++++++++++++++++++++++++++++++++++++++++++++++++++
1 files changed, 344 insertions(+), 0 deletions(-)
create mode 100644 fs/aufs/plink.c
diff --git a/fs/aufs/plink.c b/fs/aufs/plink.c
new file mode 100644
index 0000000..7197d7c
--- /dev/null
+++ b/fs/aufs/plink.c
@@ -0,0 +1,344 @@
+/*
+ * Copyright (C) 2007-2008 Junjiro Okajima
+ *
+ * This program, aufs is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; either version 2 of the License, or
+ * (at your option) any later version.
+ *
+ * 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., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA
+ */
+
+/*
+ * pseudo-link
+ */
+
+#include "aufs.h"
+
+struct pseudo_link {
+ struct list_head list;
+ struct inode *inode;
+};
+
+#ifdef CONFIG_AUFS_DEBUG
+void au_plink_list(struct super_block *sb)
+{
+ struct au_sbinfo *sbinfo;
+ struct list_head *plink_list;
+ struct pseudo_link *plink;
+
+ AuTraceEnter();
+ SiMustAnyLock(sb);
+ sbinfo = au_sbi(sb);
+ AuDebugOn(!au_opt_test(au_mntflags(sb), PLINK));
+
+ plink_list = &sbinfo->si_plink;
+ spin_lock(&sbinfo->si_plink_lock);
+ list_for_each_entry(plink, plink_list, list)
+ AuDbg("%lu\n", plink->inode->i_ino);
+ spin_unlock(&sbinfo->si_plink_lock);
+}
+#endif
+
+int au_plink_test(struct super_block *sb, struct inode *inode)
+{
+ int found;
+ struct au_sbinfo *sbinfo;
+ struct list_head *plink_list;
+ struct pseudo_link *plink;
+
+ LKTRTrace("i%lu\n", inode->i_ino);
+ SiMustAnyLock(sb);
+ sbinfo = au_sbi(sb);
+ AuDebugOn(!au_opt_test(au_mntflags(sb), PLINK));
+
+ found = 0;
+ plink_list = &sbinfo->si_plink;
+ spin_lock(&sbinfo->si_plink_lock);
+ list_for_each_entry(plink, plink_list, list)
+ if (plink->inode == inode) {
+ found = 1;
+ break;
+ }
+ spin_unlock(&sbinfo->si_plink_lock);
+ return found;
+}
+
+/* 20 is max digits length of ulong 64 */
+#define PLINK_NAME_LEN ((20 + 1) * 2)
+
+static int plink_name(char *name, int len, struct inode *inode,
+ aufs_bindex_t bindex)
+{
+ int rlen;
+ struct inode *h_inode;
+
+ LKTRTrace("i%lu, b%d\n", inode->i_ino, bindex);
+ AuDebugOn(len != PLINK_NAME_LEN);
+ h_inode = au_h_iptr(inode, bindex);
+ AuDebugOn(!h_inode);
+ rlen = snprintf(name, len, "%lu.%lu", inode->i_ino, h_inode->i_ino);
+ AuDebugOn(rlen >= len);
+ return rlen;
+}
+
+struct dentry *au_plink_lkup(struct super_block *sb, aufs_bindex_t bindex,
+ struct inode *inode)
+{
+ struct dentry *h_dentry, *h_parent;
+ struct au_branch *br;
+ struct inode *h_dir;
+ char tgtname[PLINK_NAME_LEN];
+ int len;
+ struct au_ndx ndx = {
+ .flags = 0,
+ .nd = NULL,
+ /* .br = NULL */
+ };
+
+ LKTRTrace("b%d, i%lu\n", bindex, inode->i_ino);
+ br = au_sbr(sb, bindex);
+ h_parent = br->br_plink;
+ AuDebugOn(!h_parent);
+ h_dir = h_parent->d_inode;
+ AuDebugOn(!h_dir);
+
+ len = plink_name(tgtname, sizeof(tgtname), inode, bindex);
+
+ /* always superio. */
+ ndx.nfsmnt = au_do_nfsmnt(br->br_mnt);
+ mutex_lock_nested(&h_dir->i_mutex, AuLsc_I_CHILD2);
+ h_dentry = au_sio_lkup_one(tgtname, h_parent, len, &ndx);
+ mutex_unlock(&h_dir->i_mutex);
+ return h_dentry;
+}
+
+static int do_whplink(char *tgt, int len, struct dentry *h_parent,
+ struct dentry *h_dentry, struct vfsmount *nfsmnt,
+ struct super_block *sb)
+{
+ int err, dlgt;
+ struct dentry *h_tgt;
+ struct inode *h_dir;
+ struct vfsub_args vargs;
+ struct au_ndx ndx = {
+ .nfsmnt = nfsmnt,
+ .flags = 0,
+ .nd = NULL,
+ /* .br = NULL */
+ };
+
+ dlgt = !!au_opt_test_dlgt(au_mntflags(sb));
+ if (unlikely(dlgt))
+ au_fset_ndx(ndx.flags, DLGT);
+ h_tgt = au_lkup_one(tgt, h_parent, len, &ndx);
+ err = PTR_ERR(h_tgt);
+ if (IS_ERR(h_tgt))
+ goto out;
+
+ err = 0;
+ vfsub_args_init(&vargs, NULL, dlgt, 0);
+ h_dir = h_parent->d_inode;
+ if (unlikely(h_tgt->d_inode && h_tgt->d_inode != h_dentry->d_inode))
+ err = vfsub_unlink(h_dir, h_tgt, &vargs);
+ if (!err && !h_tgt->d_inode) {
+ err = vfsub_link(h_dentry, h_dir, h_tgt, dlgt);
+ /* todo: unnecessary? */
+ /* inc_nlink(inode); */
+ }
+ dput(h_tgt);
+
+ out:
+ AuTraceErr(err);
+ return err;
+}
+
+struct do_whplink_args {
+ int *errp;
+ char *tgt;
+ int len;
+ struct dentry *h_parent;
+ struct dentry *h_dentry;
+ struct vfsmount *nfsmnt;
+ struct super_block *sb;
+};
+
+static void call_do_whplink(void *args)
+{
+ struct do_whplink_args *a = args;
+ *a->errp = do_whplink(a->tgt, a->len, a->h_parent, a->h_dentry,
+ a->nfsmnt, a->sb);
+}
+
+static int whplink(struct dentry *h_dentry, struct inode *inode,
+ aufs_bindex_t bindex, struct super_block *sb)
+{
+ int err, len, wkq_err;
+ struct au_branch *br;
+ struct dentry *h_parent;
+ struct inode *h_dir;
+ char tgtname[PLINK_NAME_LEN];
+
+ LKTRTrace("%.*s\n", AuDLNPair(h_dentry));
+ br = au_sbr(inode->i_sb, bindex);
+ h_parent = br->br_plink;
+ AuDebugOn(!h_parent);
+ h_dir = h_parent->d_inode;
+ AuDebugOn(!h_dir);
+
+ len = plink_name(tgtname, sizeof(tgtname), inode, bindex);
+
+ /* always superio. */
+ mutex_lock_nested(&h_dir->i_mutex, AuLsc_I_CHILD2);
+ if (!au_test_wkq(current)) {
+ struct do_whplink_args args = {
+ .errp = &err,
+ .tgt = tgtname,
+ .len = len,
+ .h_parent = h_parent,
+ .h_dentry = h_dentry,
+ .nfsmnt = au_do_nfsmnt(br->br_mnt),
+ .sb = sb
+ };
+ wkq_err = au_wkq_wait(call_do_whplink, &args, /*dlgt*/0);
+ if (unlikely(wkq_err))
+ err = wkq_err;
+ } else
+ err = do_whplink(tgtname, len, h_parent, h_dentry,
+ au_do_nfsmnt(br->br_mnt), sb);
+ mutex_unlock(&h_dir->i_mutex);
+
+ AuTraceErr(err);
+ return err;
+}
+
+void au_plink_append(struct super_block *sb, struct inode *inode,
+ struct dentry *h_dentry, aufs_bindex_t bindex)
+{
+ struct au_sbinfo *sbinfo;
+ struct list_head *plink_list;
+ struct pseudo_link *plink;
+ int found, err, cnt;
+
+ LKTRTrace("i%lu\n", inode->i_ino);
+ SiMustAnyLock(sb);
+ sbinfo = au_sbi(sb);
+ AuDebugOn(!au_opt_test(au_mntflags(sb), PLINK));
+
+ cnt = 0;
+ found = 0;
+ plink_list = &sbinfo->si_plink;
+ spin_lock(&sbinfo->si_plink_lock);
+ list_for_each_entry(plink, plink_list, list) {
+ cnt++;
+ if (plink->inode == inode) {
+ found = 1;
+ break;
+ }
+ }
+
+ err = 0;
+ if (!found) {
+ plink = kmalloc(sizeof(*plink), GFP_ATOMIC);
+ if (plink) {
+ plink->inode = igrab(inode);
+ list_add(&plink->list, plink_list);
+ cnt++;
+ } else
+ err = -ENOMEM;
+ }
+ spin_unlock(&sbinfo->si_plink_lock);
+
+ if (!err)
+ err = whplink(h_dentry, inode, bindex, sb);
+
+ if (unlikely(cnt > AUFS_PLINK_WARN))
+ AuWarn1("unexpectedly many pseudo links, %d\n", cnt);
+ if (unlikely(err))
+ AuWarn("err %d, damaged pseudo link. ignored.\n", err);
+}
+
+static void do_put_plink(struct pseudo_link *plink, int do_del)
+{
+ AuTraceEnter();
+
+ iput(plink->inode);
+ if (do_del)
+ list_del(&plink->list);
+ kfree(plink);
+}
+
+void au_plink_put(struct super_block *sb)
+{
+ struct au_sbinfo *sbinfo;
+ struct list_head *plink_list;
+ struct pseudo_link *plink, *tmp;
+
+ AuTraceEnter();
+ SiMustWriteLock(sb);
+ sbinfo = au_sbi(sb);
+ AuDebugOn(!au_opt_test(au_mntflags(sb), PLINK));
+
+ plink_list = &sbinfo->si_plink;
+ /* spin_lock(&sbinfo->si_plink_lock); */
+ list_for_each_entry_safe(plink, tmp, plink_list, list)
+ do_put_plink(plink, 0);
+ INIT_LIST_HEAD(plink_list);
+ /* spin_unlock(&sbinfo->si_plink_lock); */
+}
+
+void au_plink_half_refresh(struct super_block *sb, aufs_bindex_t br_id)
+{
+ struct au_sbinfo *sbinfo;
+ struct list_head *plink_list;
+ struct pseudo_link *plink, *tmp;
+ struct inode *inode;
+ aufs_bindex_t bstart, bend, bindex;
+ int do_put;
+
+ AuTraceEnter();
+ SiMustWriteLock(sb);
+ sbinfo = au_sbi(sb);
+ AuDebugOn(!au_opt_test(au_mntflags(sb), PLINK));
+
+ plink_list = &sbinfo->si_plink;
+ /* spin_lock(&sbinfo->si_plink_lock); */
+ list_for_each_entry_safe(plink, tmp, plink_list, list) {
+ do_put = 0;
+ inode = igrab(plink->inode);
+ ii_write_lock_child(inode);
+ bstart = au_ibstart(inode);
+ bend = au_ibend(inode);
+ if (bstart >= 0) {
+ for (bindex = bstart; bindex <= bend; bindex++) {
+ if (!au_h_iptr(inode, bindex)
+ || au_ii_br_id(inode, bindex) != br_id)
+ continue;
+ au_set_h_iptr(inode, bindex, NULL, 0);
+ do_put = 1;
+ break;
+ }
+ } else
+ do_put_plink(plink, 1);
+
+ if (do_put) {
+ for (bindex = bstart; bindex <= bend; bindex++)
+ if (au_h_iptr(inode, bindex)) {
+ do_put = 0;
+ break;
+ }
+ if (do_put)
+ do_put_plink(plink, 1);
+ }
+ ii_write_unlock(inode);
+ iput(inode);
+ }
+ /* spin_unlock(&sbinfo->si_plink_lock); */
+}
--
1.5.5.1.308.g1fbb5.dirty
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