--- /dev/null
+/*
+ * Copyright (C) 2005-2011 Junjiro R. 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
+ */
+
+/*
+ * whiteout for logical deletion and opaque directory
+ */
+
+#include <linux/fs.h>
+#include "aufs.h"
+
+#define WH_MASK S_IRUGO
+
+/*
+ * If a directory contains this file, then it is opaque. We start with the
+ * .wh. flag so that it is blocked by lookup.
+ */
+static struct qstr diropq_name = {
+ .name = AUFS_WH_DIROPQ,
+ .len = sizeof(AUFS_WH_DIROPQ) - 1
+};
+
+/*
+ * generate whiteout name, which is NOT terminated by NULL.
+ * @name: original d_name.name
+ * @len: original d_name.len
+ * @wh: whiteout qstr
+ * returns zero when succeeds, otherwise error.
+ * succeeded value as wh->name should be freed by kfree().
+ */
+int au_wh_name_alloc(struct qstr *wh, const struct qstr *name)
+{
+ char *p;
+
+ if (unlikely(name->len > PATH_MAX - AUFS_WH_PFX_LEN))
+ return -ENAMETOOLONG;
+
+ wh->len = name->len + AUFS_WH_PFX_LEN;
+ p = kmalloc(wh->len, GFP_NOFS);
+ wh->name = p;
+ if (p) {
+ memcpy(p, AUFS_WH_PFX, AUFS_WH_PFX_LEN);
+ memcpy(p + AUFS_WH_PFX_LEN, name->name, name->len);
+ /* smp_mb(); */
+ return 0;
+ }
+ return -ENOMEM;
+}
+
+/* ---------------------------------------------------------------------- */
+
+/*
+ * test if the @wh_name exists under @h_parent.
+ * @try_sio specifies the necessary of super-io.
+ */
+int au_wh_test(struct dentry *h_parent, struct qstr *wh_name,
+ struct au_branch *br, int try_sio)
+{
+ int err;
+ struct dentry *wh_dentry;
+
+ if (!try_sio)
+ wh_dentry = au_lkup_one(wh_name, h_parent, br, /*nd*/NULL);
+ else
+ wh_dentry = au_sio_lkup_one(wh_name, h_parent, br);
+ err = PTR_ERR(wh_dentry);
+ if (IS_ERR(wh_dentry))
+ goto out;
+
+ err = 0;
+ if (!wh_dentry->d_inode)
+ goto out_wh; /* success */
+
+ err = 1;
+ if (S_ISREG(wh_dentry->d_inode->i_mode))
+ goto out_wh; /* success */
+
+ err = -EIO;
+ AuIOErr("%.*s Invalid whiteout entry type 0%o.\n",
+ AuDLNPair(wh_dentry), wh_dentry->d_inode->i_mode);
+
+out_wh:
+ dput(wh_dentry);
+out:
+ return err;
+}
+
+/*
+ * test if the @h_dentry sets opaque or not.
+ */
+int au_diropq_test(struct dentry *h_dentry, struct au_branch *br)
+{
+ int err;
+ struct inode *h_dir;
+
+ h_dir = h_dentry->d_inode;
+ err = au_wh_test(h_dentry, &diropq_name, br,
+ au_test_h_perm_sio(h_dir, MAY_EXEC));
+ return err;
+}
+
+/*
+ * returns a negative dentry whose name is unique and temporary.
+ */
+struct dentry *au_whtmp_lkup(struct dentry *h_parent, struct au_branch *br,
+ struct qstr *prefix)
+{
+ struct dentry *dentry;
+ int i;
+ char defname[NAME_MAX - AUFS_MAX_NAMELEN + DNAME_INLINE_LEN + 1],
+ *name, *p;
+ /* strict atomic_t is unnecessary here */
+ static unsigned short cnt;
+ struct qstr qs;
+
+ BUILD_BUG_ON(sizeof(cnt) * 2 > AUFS_WH_TMP_LEN);
+
+ name = defname;
+ qs.len = sizeof(defname) - DNAME_INLINE_LEN + prefix->len - 1;
+ if (unlikely(prefix->len > DNAME_INLINE_LEN)) {
+ dentry = ERR_PTR(-ENAMETOOLONG);
+ if (unlikely(qs.len > NAME_MAX))
+ goto out;
+ dentry = ERR_PTR(-ENOMEM);
+ name = kmalloc(qs.len + 1, GFP_NOFS);
+ if (unlikely(!name))
+ goto out;
+ }
+
+ /* doubly whiteout-ed */
+ memcpy(name, AUFS_WH_PFX AUFS_WH_PFX, AUFS_WH_PFX_LEN * 2);
+ p = name + AUFS_WH_PFX_LEN * 2;
+ memcpy(p, prefix->name, prefix->len);
+ p += prefix->len;
+ *p++ = '.';
+ AuDebugOn(name + qs.len + 1 - p <= AUFS_WH_TMP_LEN);
+
+ qs.name = name;
+ for (i = 0; i < 3; i++) {
+ sprintf(p, "%.*x", AUFS_WH_TMP_LEN, cnt++);
+ dentry = au_sio_lkup_one(&qs, h_parent, br);
+ if (IS_ERR(dentry) || !dentry->d_inode)
+ goto out_name;
+ dput(dentry);
+ }
+ /* pr_warning("could not get random name\n"); */
+ dentry = ERR_PTR(-EEXIST);
+ AuDbg("%.*s\n", AuLNPair(&qs));
+ BUG();
+
+out_name:
+ if (name != defname)
+ kfree(name);
+out:
+ AuTraceErrPtr(dentry);
+ return dentry;
+}
+
+/*
+ * rename the @h_dentry on @br to the whiteouted temporary name.
+ */
+int au_whtmp_ren(struct dentry *h_dentry, struct au_branch *br)
+{
+ int err;
+ struct path h_path = {
+ .mnt = br->br_mnt
+ };
+ struct inode *h_dir;
+ struct dentry *h_parent;
+
+ h_parent = h_dentry->d_parent; /* dir inode is locked */
+ h_dir = h_parent->d_inode;
+ IMustLock(h_dir);
+
+ h_path.dentry = au_whtmp_lkup(h_parent, br, &h_dentry->d_name);
+ err = PTR_ERR(h_path.dentry);
+ if (IS_ERR(h_path.dentry))
+ goto out;
+
+ /* under the same dir, no need to lock_rename() */
+ err = vfsub_rename(h_dir, h_dentry, h_dir, &h_path);
+ AuTraceErr(err);
+ dput(h_path.dentry);
+
+out:
+ AuTraceErr(err);
+ return err;
+}
+
+/* ---------------------------------------------------------------------- */
+/*
+ * functions for removing a whiteout
+ */
+
+static int do_unlink_wh(struct inode *h_dir, struct path *h_path)
+{
+ int force;
+
+ /*
+ * forces superio when the dir has a sticky bit.
+ * this may be a violation of unix fs semantics.
+ */
+ force = (h_dir->i_mode & S_ISVTX)
+ && h_path->dentry->d_inode->i_uid != current_fsuid();
+ return vfsub_unlink(h_dir, h_path, force);
+}
+
+int au_wh_unlink_dentry(struct inode *h_dir, struct path *h_path,
+ struct dentry *dentry)
+{
+ int err;
+
+ err = do_unlink_wh(h_dir, h_path);
+ if (!err && dentry)
+ au_set_dbwh(dentry, -1);
+
+ return err;
+}
+
+static int unlink_wh_name(struct dentry *h_parent, struct qstr *wh,
+ struct au_branch *br)
+{
+ int err;
+ struct path h_path = {
+ .mnt = br->br_mnt
+ };
+
+ err = 0;
+ h_path.dentry = au_lkup_one(wh, h_parent, br, /*nd*/NULL);
+ if (IS_ERR(h_path.dentry))
+ err = PTR_ERR(h_path.dentry);
+ else {
+ if (h_path.dentry->d_inode
+ && S_ISREG(h_path.dentry->d_inode->i_mode))
+ err = do_unlink_wh(h_parent->d_inode, &h_path);
+ dput(h_path.dentry);
+ }
+
+ return err;
+}
+
+/* ---------------------------------------------------------------------- */
+/*
+ * initialize/clean whiteout for a branch
+ */
+
+static void au_wh_clean(struct inode *h_dir, struct path *whpath,
+ const int isdir)
+{
+ int err;
+
+ if (!whpath->dentry->d_inode)
+ return;
+
+ err = mnt_want_write(whpath->mnt);
+ if (!err) {
+ if (isdir)
+ err = vfsub_rmdir(h_dir, whpath);
+ else
+ err = vfsub_unlink(h_dir, whpath, /*force*/0);
+ mnt_drop_write(whpath->mnt);
+ }
+ if (unlikely(err))
+ pr_warning("failed removing %.*s (%d), ignored.\n",
+ AuDLNPair(whpath->dentry), err);
+}
+
+static int test_linkable(struct dentry *h_root)
+{
+ struct inode *h_dir = h_root->d_inode;
+
+ if (h_dir->i_op->link)
+ return 0;
+
+ pr_err("%.*s (%s) doesn't support link(2), use noplink and rw+nolwh\n",
+ AuDLNPair(h_root), au_sbtype(h_root->d_sb));
+ return -ENOSYS;
+}
+
+/* todo: should this mkdir be done in /sbin/mount.aufs helper? */
+static int au_whdir(struct inode *h_dir, struct path *path)
+{
+ int err;
+
+ err = -EEXIST;
+ if (!path->dentry->d_inode) {
+ int mode = S_IRWXU;
+
+ if (au_test_nfs(path->dentry->d_sb))
+ mode |= S_IXUGO;
+ err = mnt_want_write(path->mnt);
+ if (!err) {
+ err = vfsub_mkdir(h_dir, path, mode);
+ mnt_drop_write(path->mnt);
+ }
+ } else if (S_ISDIR(path->dentry->d_inode->i_mode))
+ err = 0;
+ else
+ pr_err("unknown %.*s exists\n", AuDLNPair(path->dentry));
+
+ return err;
+}
+
+struct au_wh_base {
+ const struct qstr *name;
+ struct dentry *dentry;
+};
+
+static void au_wh_init_ro(struct inode *h_dir, struct au_wh_base base[],
+ struct path *h_path)
+{
+ h_path->dentry = base[AuBrWh_BASE].dentry;
+ au_wh_clean(h_dir, h_path, /*isdir*/0);
+ h_path->dentry = base[AuBrWh_PLINK].dentry;
+ au_wh_clean(h_dir, h_path, /*isdir*/1);
+ h_path->dentry = base[AuBrWh_ORPH].dentry;
+ au_wh_clean(h_dir, h_path, /*isdir*/1);
+}
+
+/*
+ * returns tri-state,
+ * minus: error, caller should print the mesage
+ * zero: succuess
+ * plus: error, caller should NOT print the mesage
+ */
+static int au_wh_init_rw_nolink(struct dentry *h_root, struct au_wbr *wbr,
+ int do_plink, struct au_wh_base base[],
+ struct path *h_path)
+{
+ int err;
+ struct inode *h_dir;
+
+ h_dir = h_root->d_inode;
+ h_path->dentry = base[AuBrWh_BASE].dentry;
+ au_wh_clean(h_dir, h_path, /*isdir*/0);
+ h_path->dentry = base[AuBrWh_PLINK].dentry;
+ if (do_plink) {
+ err = test_linkable(h_root);
+ if (unlikely(err)) {
+ err = 1;
+ goto out;
+ }
+
+ err = au_whdir(h_dir, h_path);
+ if (unlikely(err))
+ goto out;
+ wbr->wbr_plink = dget(base[AuBrWh_PLINK].dentry);
+ } else
+ au_wh_clean(h_dir, h_path, /*isdir*/1);
+ h_path->dentry = base[AuBrWh_ORPH].dentry;
+ err = au_whdir(h_dir, h_path);
+ if (unlikely(err))
+ goto out;
+ wbr->wbr_orph = dget(base[AuBrWh_ORPH].dentry);
+
+out:
+ return err;
+}
+
+/*
+ * for the moment, aufs supports the branch filesystem which does not support
+ * link(2). testing on FAT which does not support i_op->setattr() fully either,
+ * copyup failed. finally, such filesystem will not be used as the writable
+ * branch.
+ *
+ * returns tri-state, see above.
+ */
+static int au_wh_init_rw(struct dentry *h_root, struct au_wbr *wbr,
+ int do_plink, struct au_wh_base base[],
+ struct path *h_path)
+{
+ int err;
+ struct inode *h_dir;
+
+ WbrWhMustWriteLock(wbr);
+
+ err = test_linkable(h_root);
+ if (unlikely(err)) {
+ err = 1;
+ goto out;
+ }
+
+ /*
+ * todo: should this create be done in /sbin/mount.aufs helper?
+ */
+ err = -EEXIST;
+ h_dir = h_root->d_inode;
+ if (!base[AuBrWh_BASE].dentry->d_inode) {
+ err = mnt_want_write(h_path->mnt);
+ if (!err) {
+ h_path->dentry = base[AuBrWh_BASE].dentry;
+ err = vfsub_create(h_dir, h_path, WH_MASK);
+ mnt_drop_write(h_path->mnt);
+ }
+ } else if (S_ISREG(base[AuBrWh_BASE].dentry->d_inode->i_mode))
+ err = 0;
+ else
+ pr_err("unknown %.*s/%.*s exists\n",
+ AuDLNPair(h_root), AuDLNPair(base[AuBrWh_BASE].dentry));
+ if (unlikely(err))
+ goto out;
+
+ h_path->dentry = base[AuBrWh_PLINK].dentry;
+ if (do_plink) {
+ err = au_whdir(h_dir, h_path);
+ if (unlikely(err))
+ goto out;
+ wbr->wbr_plink = dget(base[AuBrWh_PLINK].dentry);
+ } else
+ au_wh_clean(h_dir, h_path, /*isdir*/1);
+ wbr->wbr_whbase = dget(base[AuBrWh_BASE].dentry);
+
+ h_path->dentry = base[AuBrWh_ORPH].dentry;
+ err = au_whdir(h_dir, h_path);
+ if (unlikely(err))
+ goto out;
+ wbr->wbr_orph = dget(base[AuBrWh_ORPH].dentry);
+
+out:
+ return err;
+}
+
+/*
+ * initialize the whiteout base file/dir for @br.
+ */
+int au_wh_init(struct dentry *h_root, struct au_branch *br,
+ struct super_block *sb)
+{
+ int err, i;
+ const unsigned char do_plink
+ = !!au_opt_test(au_mntflags(sb), PLINK);
+ struct path path = {
+ .mnt = br->br_mnt
+ };
+ struct inode *h_dir;
+ struct au_wbr *wbr = br->br_wbr;
+ static const struct qstr base_name[] = {
+ [AuBrWh_BASE] = {
+ .name = AUFS_BASE_NAME,
+ .len = sizeof(AUFS_BASE_NAME) - 1
+ },
+ [AuBrWh_PLINK] = {
+ .name = AUFS_PLINKDIR_NAME,
+ .len = sizeof(AUFS_PLINKDIR_NAME) - 1
+ },
+ [AuBrWh_ORPH] = {
+ .name = AUFS_ORPHDIR_NAME,
+ .len = sizeof(AUFS_ORPHDIR_NAME) - 1
+ }
+ };
+ struct au_wh_base base[] = {
+ [AuBrWh_BASE] = {
+ .name = base_name + AuBrWh_BASE,
+ .dentry = NULL
+ },
+ [AuBrWh_PLINK] = {
+ .name = base_name + AuBrWh_PLINK,
+ .dentry = NULL
+ },
+ [AuBrWh_ORPH] = {
+ .name = base_name + AuBrWh_ORPH,
+ .dentry = NULL
+ }
+ };
+
+ if (wbr)
+ WbrWhMustWriteLock(wbr);
+
+ for (i = 0; i < AuBrWh_Last; i++) {
+ /* doubly whiteouted */
+ struct dentry *d;
+
+ d = au_wh_lkup(h_root, (void *)base[i].name, br);
+ err = PTR_ERR(d);
+ if (IS_ERR(d))
+ goto out;
+
+ base[i].dentry = d;
+ AuDebugOn(wbr
+ && wbr->wbr_wh[i]
+ && wbr->wbr_wh[i] != base[i].dentry);
+ }
+
+ if (wbr)
+ for (i = 0; i < AuBrWh_Last; i++) {
+ dput(wbr->wbr_wh[i]);
+ wbr->wbr_wh[i] = NULL;
+ }
+
+ err = 0;
+ switch (br->br_perm) {
+ case AuBrPerm_RO:
+ case AuBrPerm_ROWH:
+ case AuBrPerm_RR:
+ case AuBrPerm_RRWH:
+ h_dir = h_root->d_inode;
+ au_wh_init_ro(h_dir, base, &path);
+ break;
+
+ case AuBrPerm_RWNoLinkWH:
+ err = au_wh_init_rw_nolink(h_root, wbr, do_plink, base, &path);
+ if (err > 0)
+ goto out;
+ else if (err)
+ goto out_err;
+ break;
+
+ case AuBrPerm_RW:
+ err = au_wh_init_rw(h_root, wbr, do_plink, base, &path);
+ if (err > 0)
+ goto out;
+ else if (err)
+ goto out_err;
+ break;
+
+ default:
+ BUG();
+ }
+ goto out; /* success */
+
+out_err:
+ pr_err("an error(%d) on the writable branch %.*s(%s)\n",
+ err, AuDLNPair(h_root), au_sbtype(h_root->d_sb));
+out:
+ for (i = 0; i < AuBrWh_Last; i++)
+ dput(base[i].dentry);
+ return err;
+}
+
+/* ---------------------------------------------------------------------- */
+/*
+ * whiteouts are all hard-linked usually.
+ * when its link count reaches a ceiling, we create a new whiteout base
+ * asynchronously.
+ */
+
+struct reinit_br_wh {
+ struct super_block *sb;
+ struct au_branch *br;
+};
+
+static void reinit_br_wh(void *arg)
+{
+ int err;
+ aufs_bindex_t bindex;
+ struct path h_path;
+ struct reinit_br_wh *a = arg;
+ struct au_wbr *wbr;
+ struct inode *dir;
+ struct dentry *h_root;
+ struct au_hinode *hdir;
+
+ err = 0;
+ wbr = a->br->br_wbr;
+ /* big aufs lock */
+ si_noflush_write_lock(a->sb);
+ if (!au_br_writable(a->br->br_perm))
+ goto out;
+ bindex = au_br_index(a->sb, a->br->br_id);
+ if (unlikely(bindex < 0))
+ goto out;
+
+ di_read_lock_parent(a->sb->s_root, AuLock_IR);
+ dir = a->sb->s_root->d_inode;
+ hdir = au_hi(dir, bindex);
+ h_root = au_h_dptr(a->sb->s_root, bindex);
+
+ au_hn_imtx_lock_nested(hdir, AuLsc_I_PARENT);
+ wbr_wh_write_lock(wbr);
+ err = au_h_verify(wbr->wbr_whbase, au_opt_udba(a->sb), hdir->hi_inode,
+ h_root, a->br);
+ if (!err) {
+ err = mnt_want_write(a->br->br_mnt);
+ if (!err) {
+ h_path.dentry = wbr->wbr_whbase;
+ h_path.mnt = a->br->br_mnt;
+ err = vfsub_unlink(hdir->hi_inode, &h_path, /*force*/0);
+ mnt_drop_write(a->br->br_mnt);
+ }
+ } else {
+ pr_warning("%.*s is moved, ignored\n",
+ AuDLNPair(wbr->wbr_whbase));
+ err = 0;
+ }
+ dput(wbr->wbr_whbase);
+ wbr->wbr_whbase = NULL;
+ if (!err)
+ err = au_wh_init(h_root, a->br, a->sb);
+ wbr_wh_write_unlock(wbr);
+ au_hn_imtx_unlock(hdir);
+ di_read_unlock(a->sb->s_root, AuLock_IR);
+
+out:
+ if (wbr)
+ atomic_dec(&wbr->wbr_wh_running);
+ atomic_dec(&a->br->br_count);
+ si_write_unlock(a->sb);
+ au_nwt_done(&au_sbi(a->sb)->si_nowait);
+ kfree(arg);
+ if (unlikely(err))
+ AuIOErr("err %d\n", err);
+}
+
+static void kick_reinit_br_wh(struct super_block *sb, struct au_branch *br)
+{
+ int do_dec, wkq_err;
+ struct reinit_br_wh *arg;
+
+ do_dec = 1;
+ if (atomic_inc_return(&br->br_wbr->wbr_wh_running) != 1)
+ goto out;
+
+ /* ignore ENOMEM */
+ arg = kmalloc(sizeof(*arg), GFP_NOFS);
+ if (arg) {
+ /*
+ * dec(wh_running), kfree(arg) and dec(br_count)
+ * in reinit function
+ */
+ arg->sb = sb;
+ arg->br = br;
+ atomic_inc(&br->br_count);
+ wkq_err = au_wkq_nowait(reinit_br_wh, arg, sb);
+ if (unlikely(wkq_err)) {
+ atomic_dec(&br->br_wbr->wbr_wh_running);
+ atomic_dec(&br->br_count);
+ kfree(arg);
+ }
+ do_dec = 0;
+ }
+
+out:
+ if (do_dec)
+ atomic_dec(&br->br_wbr->wbr_wh_running);
+}
+
+/* ---------------------------------------------------------------------- */
+
+/*
+ * create the whiteout @wh.
+ */
+static int link_or_create_wh(struct super_block *sb, aufs_bindex_t bindex,
+ struct dentry *wh)
+{
+ int err;
+ struct path h_path = {
+ .dentry = wh
+ };
+ struct au_branch *br;
+ struct au_wbr *wbr;
+ struct dentry *h_parent;
+ struct inode *h_dir;
+
+ h_parent = wh->d_parent; /* dir inode is locked */
+ h_dir = h_parent->d_inode;
+ IMustLock(h_dir);
+
+ br = au_sbr(sb, bindex);
+ h_path.mnt = br->br_mnt;
+ wbr = br->br_wbr;
+ wbr_wh_read_lock(wbr);
+ if (wbr->wbr_whbase) {
+ err = vfsub_link(wbr->wbr_whbase, h_dir, &h_path);
+ if (!err || err != -EMLINK)
+ goto out;
+
+ /* link count full. re-initialize br_whbase. */
+ kick_reinit_br_wh(sb, br);
+ }
+
+ /* return this error in this context */
+ err = vfsub_create(h_dir, &h_path, WH_MASK);
+
+out:
+ wbr_wh_read_unlock(wbr);
+ return err;
+}
+
+/* ---------------------------------------------------------------------- */
+
+/*
+ * create or remove the diropq.
+ */
+static struct dentry *do_diropq(struct dentry *dentry, aufs_bindex_t bindex,
+ unsigned int flags)
+{
+ struct dentry *opq_dentry, *h_dentry;
+ struct super_block *sb;
+ struct au_branch *br;
+ int err;
+
+ sb = dentry->d_sb;
+ br = au_sbr(sb, bindex);
+ h_dentry = au_h_dptr(dentry, bindex);
+ opq_dentry = au_lkup_one(&diropq_name, h_dentry, br, /*nd*/NULL);
+ if (IS_ERR(opq_dentry))
+ goto out;
+
+ if (au_ftest_diropq(flags, CREATE)) {
+ err = link_or_create_wh(sb, bindex, opq_dentry);
+ if (!err) {
+ au_set_dbdiropq(dentry, bindex);
+ goto out; /* success */
+ }
+ } else {
+ struct path tmp = {
+ .dentry = opq_dentry,
+ .mnt = br->br_mnt
+ };
+ err = do_unlink_wh(au_h_iptr(dentry->d_inode, bindex), &tmp);
+ if (!err)
+ au_set_dbdiropq(dentry, -1);
+ }
+ dput(opq_dentry);
+ opq_dentry = ERR_PTR(err);
+
+out:
+ return opq_dentry;
+}
+
+struct do_diropq_args {
+ struct dentry **errp;
+ struct dentry *dentry;
+ aufs_bindex_t bindex;
+ unsigned int flags;
+};
+
+static void call_do_diropq(void *args)
+{
+ struct do_diropq_args *a = args;
+ *a->errp = do_diropq(a->dentry, a->bindex, a->flags);
+}
+
+struct dentry *au_diropq_sio(struct dentry *dentry, aufs_bindex_t bindex,
+ unsigned int flags)
+{
+ struct dentry *diropq, *h_dentry;
+
+ h_dentry = au_h_dptr(dentry, bindex);
+ if (!au_test_h_perm_sio(h_dentry->d_inode, MAY_EXEC | MAY_WRITE))
+ diropq = do_diropq(dentry, bindex, flags);
+ else {
+ int wkq_err;
+ struct do_diropq_args args = {
+ .errp = &diropq,
+ .dentry = dentry,
+ .bindex = bindex,
+ .flags = flags
+ };
+
+ wkq_err = au_wkq_wait(call_do_diropq, &args);
+ if (unlikely(wkq_err))
+ diropq = ERR_PTR(wkq_err);
+ }
+
+ return diropq;
+}
+
+/* ---------------------------------------------------------------------- */
+
+/*
+ * lookup whiteout dentry.
+ * @h_parent: lower parent dentry which must exist and be locked
+ * @base_name: name of dentry which will be whiteouted
+ * returns dentry for whiteout.
+ */
+struct dentry *au_wh_lkup(struct dentry *h_parent, struct qstr *base_name,
+ struct au_branch *br)
+{
+ int err;
+ struct qstr wh_name;
+ struct dentry *wh_dentry;
+
+ err = au_wh_name_alloc(&wh_name, base_name);
+ wh_dentry = ERR_PTR(err);
+ if (!err) {
+ wh_dentry = au_lkup_one(&wh_name, h_parent, br, /*nd*/NULL);
+ kfree(wh_name.name);
+ }
+ return wh_dentry;
+}
+
+/*
+ * link/create a whiteout for @dentry on @bindex.
+ */
+struct dentry *au_wh_create(struct dentry *dentry, aufs_bindex_t bindex,
+ struct dentry *h_parent)
+{
+ struct dentry *wh_dentry;
+ struct super_block *sb;
+ int err;
+
+ sb = dentry->d_sb;
+ wh_dentry = au_wh_lkup(h_parent, &dentry->d_name, au_sbr(sb, bindex));
+ if (!IS_ERR(wh_dentry) && !wh_dentry->d_inode) {
+ err = link_or_create_wh(sb, bindex, wh_dentry);
+ if (!err)
+ au_set_dbwh(dentry, bindex);
+ else {
+ dput(wh_dentry);
+ wh_dentry = ERR_PTR(err);
+ }
+ }
+
+ return wh_dentry;
+}
+
+/* ---------------------------------------------------------------------- */
+
+/* Delete all whiteouts in this directory on branch bindex. */
+static int del_wh_children(struct dentry *h_dentry, struct au_nhash *whlist,
+ aufs_bindex_t bindex, struct au_branch *br)
+{
+ int err;
+ unsigned long ul, n;
+ struct qstr wh_name;
+ char *p;
+ struct hlist_head *head;
+ struct au_vdir_wh *tpos;
+ struct hlist_node *pos;
+ struct au_vdir_destr *str;
+
+ err = -ENOMEM;
+ p = __getname_gfp(GFP_NOFS);
+ wh_name.name = p;
+ if (unlikely(!wh_name.name))
+ goto out;
+
+ err = 0;
+ memcpy(p, AUFS_WH_PFX, AUFS_WH_PFX_LEN);
+ p += AUFS_WH_PFX_LEN;
+ n = whlist->nh_num;
+ head = whlist->nh_head;
+ for (ul = 0; !err && ul < n; ul++, head++) {
+ hlist_for_each_entry(tpos, pos, head, wh_hash) {
+ if (tpos->wh_bindex != bindex)
+ continue;
+
+ str = &tpos->wh_str;
+ if (str->len + AUFS_WH_PFX_LEN <= PATH_MAX) {
+ memcpy(p, str->name, str->len);
+ wh_name.len = AUFS_WH_PFX_LEN + str->len;
+ err = unlink_wh_name(h_dentry, &wh_name, br);
+ if (!err)
+ continue;
+ break;
+ }
+ AuIOErr("whiteout name too long %.*s\n",
+ str->len, str->name);
+ err = -EIO;
+ break;
+ }
+ }
+ __putname(wh_name.name);
+
+out:
+ return err;
+}
+
+struct del_wh_children_args {
+ int *errp;
+ struct dentry *h_dentry;
+ struct au_nhash *whlist;
+ aufs_bindex_t bindex;
+ struct au_branch *br;
+};
+
+static void call_del_wh_children(void *args)
+{
+ struct del_wh_children_args *a = args;
+ *a->errp = del_wh_children(a->h_dentry, a->whlist, a->bindex, a->br);
+}
+
+/* ---------------------------------------------------------------------- */
+
+struct au_whtmp_rmdir *au_whtmp_rmdir_alloc(struct super_block *sb, gfp_t gfp)
+{
+ struct au_whtmp_rmdir *whtmp;
+ int err;
+ unsigned int rdhash;
+
+ SiMustAnyLock(sb);
+
+ whtmp = kmalloc(sizeof(*whtmp), gfp);
+ if (unlikely(!whtmp)) {
+ whtmp = ERR_PTR(-ENOMEM);
+ goto out;
+ }
+
+ whtmp->dir = NULL;
+ whtmp->br = NULL;
+ whtmp->wh_dentry = NULL;
+ /* no estimation for dir size */
+ rdhash = au_sbi(sb)->si_rdhash;
+ if (!rdhash)
+ rdhash = AUFS_RDHASH_DEF;
+ err = au_nhash_alloc(&whtmp->whlist, rdhash, gfp);
+ if (unlikely(err)) {
+ kfree(whtmp);
+ whtmp = ERR_PTR(err);
+ }
+
+out:
+ return whtmp;
+}
+
+void au_whtmp_rmdir_free(struct au_whtmp_rmdir *whtmp)
+{
+ if (whtmp->br)
+ atomic_dec(&whtmp->br->br_count);
+ dput(whtmp->wh_dentry);
+ iput(whtmp->dir);
+ au_nhash_wh_free(&whtmp->whlist);
+ kfree(whtmp);
+}
+
+/*
+ * rmdir the whiteouted temporary named dir @h_dentry.
+ * @whlist: whiteouted children.
+ */
+int au_whtmp_rmdir(struct inode *dir, aufs_bindex_t bindex,
+ struct dentry *wh_dentry, struct au_nhash *whlist)
+{
+ int err;
+ struct path h_tmp;
+ struct inode *wh_inode, *h_dir;
+ struct au_branch *br;
+
+ h_dir = wh_dentry->d_parent->d_inode; /* dir inode is locked */
+ IMustLock(h_dir);
+
+ br = au_sbr(dir->i_sb, bindex);
+ wh_inode = wh_dentry->d_inode;
+ mutex_lock_nested(&wh_inode->i_mutex, AuLsc_I_CHILD);
+
+ /*
+ * someone else might change some whiteouts while we were sleeping.
+ * it means this whlist may have an obsoleted entry.
+ */
+ if (!au_test_h_perm_sio(wh_inode, MAY_EXEC | MAY_WRITE))
+ err = del_wh_children(wh_dentry, whlist, bindex, br);
+ else {
+ int wkq_err;
+ struct del_wh_children_args args = {
+ .errp = &err,
+ .h_dentry = wh_dentry,
+ .whlist = whlist,
+ .bindex = bindex,
+ .br = br
+ };
+
+ wkq_err = au_wkq_wait(call_del_wh_children, &args);
+ if (unlikely(wkq_err))
+ err = wkq_err;
+ }
+ mutex_unlock(&wh_inode->i_mutex);
+
+ if (!err) {
+ h_tmp.dentry = wh_dentry;
+ h_tmp.mnt = br->br_mnt;
+ err = vfsub_rmdir(h_dir, &h_tmp);
+ }
+
+ if (!err) {
+ if (au_ibstart(dir) == bindex) {
+ /* todo: dir->i_mutex is necessary */
+ au_cpup_attr_timesizes(dir);
+ vfsub_drop_nlink(dir);
+ }
+ return 0; /* success */
+ }
+
+ pr_warning("failed removing %.*s(%d), ignored\n",
+ AuDLNPair(wh_dentry), err);
+ return err;
+}
+
+static void call_rmdir_whtmp(void *args)
+{
+ int err;
+ aufs_bindex_t bindex;
+ struct au_whtmp_rmdir *a = args;
+ struct super_block *sb;
+ struct dentry *h_parent;
+ struct inode *h_dir;
+ struct au_hinode *hdir;
+
+ /* rmdir by nfsd may cause deadlock with this i_mutex */
+ /* mutex_lock(&a->dir->i_mutex); */
+ err = -EROFS;
+ sb = a->dir->i_sb;
+ si_read_lock(sb, !AuLock_FLUSH);
+ if (!au_br_writable(a->br->br_perm))
+ goto out;
+ bindex = au_br_index(sb, a->br->br_id);
+ if (unlikely(bindex < 0))
+ goto out;
+
+ err = -EIO;
+ ii_write_lock_parent(a->dir);
+ h_parent = dget_parent(a->wh_dentry);
+ h_dir = h_parent->d_inode;
+ hdir = au_hi(a->dir, bindex);
+ au_hn_imtx_lock_nested(hdir, AuLsc_I_PARENT);
+ err = au_h_verify(a->wh_dentry, au_opt_udba(sb), h_dir, h_parent,
+ a->br);
+ if (!err) {
+ err = mnt_want_write(a->br->br_mnt);
+ if (!err) {
+ err = au_whtmp_rmdir(a->dir, bindex, a->wh_dentry,
+ &a->whlist);
+ mnt_drop_write(a->br->br_mnt);
+ }
+ }
+ au_hn_imtx_unlock(hdir);
+ dput(h_parent);
+ ii_write_unlock(a->dir);
+
+out:
+ /* mutex_unlock(&a->dir->i_mutex); */
+ au_whtmp_rmdir_free(a);
+ si_read_unlock(sb);
+ au_nwt_done(&au_sbi(sb)->si_nowait);
+ if (unlikely(err))
+ AuIOErr("err %d\n", err);
+}
+
+void au_whtmp_kick_rmdir(struct inode *dir, aufs_bindex_t bindex,
+ struct dentry *wh_dentry, struct au_whtmp_rmdir *args)
+{
+ int wkq_err;
+ struct super_block *sb;
+
+ IMustLock(dir);
+
+ /* all post-process will be done in do_rmdir_whtmp(). */
+ sb = dir->i_sb;
+ args->dir = au_igrab(dir);
+ args->br = au_sbr(sb, bindex);
+ atomic_inc(&args->br->br_count);
+ args->wh_dentry = dget(wh_dentry);
+ wkq_err = au_wkq_nowait(call_rmdir_whtmp, args, sb);
+ if (unlikely(wkq_err)) {
+ pr_warning("rmdir error %.*s (%d), ignored\n",
+ AuDLNPair(wh_dentry), wkq_err);
+ au_whtmp_rmdir_free(args);
+ }
+}
git.openpandora.org / pandora-kernel.git / blobdiff