--- /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
+ */
+
+/*
+ * inode operations (del entry)
+ */
+
+#include "aufs.h"
+
+/*
+ * decide if a new whiteout for @dentry is necessary or not.
+ * when it is necessary, prepare the parent dir for the upper branch whose
+ * branch index is @bcpup for creation. the actual creation of the whiteout will
+ * be done by caller.
+ * return value:
+ * 0: wh is unnecessary
+ * plus: wh is necessary
+ * minus: error
+ */
+int au_wr_dir_need_wh(struct dentry *dentry, int isdir, aufs_bindex_t *bcpup)
+{
+ int need_wh, err;
+ aufs_bindex_t bstart;
+ struct super_block *sb;
+
+ sb = dentry->d_sb;
+ bstart = au_dbstart(dentry);
+ if (*bcpup < 0) {
+ *bcpup = bstart;
+ if (au_test_ro(sb, bstart, dentry->d_inode)) {
+ err = AuWbrCopyup(au_sbi(sb), dentry);
+ *bcpup = err;
+ if (unlikely(err < 0))
+ goto out;
+ }
+ } else
+ AuDebugOn(bstart < *bcpup
+ || au_test_ro(sb, *bcpup, dentry->d_inode));
+ AuDbg("bcpup %d, bstart %d\n", *bcpup, bstart);
+
+ if (*bcpup != bstart) {
+ err = au_cpup_dirs(dentry, *bcpup);
+ if (unlikely(err))
+ goto out;
+ need_wh = 1;
+ } else {
+ struct au_dinfo *dinfo, *tmp;
+
+ need_wh = -ENOMEM;
+ dinfo = au_di(dentry);
+ tmp = au_di_alloc(sb, AuLsc_DI_TMP);
+ if (tmp) {
+ au_di_cp(tmp, dinfo);
+ au_di_swap(tmp, dinfo);
+ /* returns the number of positive dentries */
+ need_wh = au_lkup_dentry(dentry, bstart + 1, /*type*/0,
+ /*nd*/NULL);
+ au_di_swap(tmp, dinfo);
+ au_rw_write_unlock(&tmp->di_rwsem);
+ au_di_free(tmp);
+ }
+ }
+ AuDbg("need_wh %d\n", need_wh);
+ err = need_wh;
+
+out:
+ return err;
+}
+
+/*
+ * simple tests for the del-entry operations.
+ * following the checks in vfs, plus the parent-child relationship.
+ */
+int au_may_del(struct dentry *dentry, aufs_bindex_t bindex,
+ struct dentry *h_parent, int isdir)
+{
+ int err;
+ umode_t h_mode;
+ struct dentry *h_dentry, *h_latest;
+ struct inode *h_inode;
+
+ h_dentry = au_h_dptr(dentry, bindex);
+ h_inode = h_dentry->d_inode;
+ if (dentry->d_inode) {
+ err = -ENOENT;
+ if (unlikely(!h_inode || !h_inode->i_nlink))
+ goto out;
+
+ h_mode = h_inode->i_mode;
+ if (!isdir) {
+ err = -EISDIR;
+ if (unlikely(S_ISDIR(h_mode)))
+ goto out;
+ } else if (unlikely(!S_ISDIR(h_mode))) {
+ err = -ENOTDIR;
+ goto out;
+ }
+ } else {
+ /* rename(2) case */
+ err = -EIO;
+ if (unlikely(h_inode))
+ goto out;
+ }
+
+ err = -ENOENT;
+ /* expected parent dir is locked */
+ if (unlikely(h_parent != h_dentry->d_parent))
+ goto out;
+ err = 0;
+
+ /*
+ * rmdir a dir may break the consistency on some filesystem.
+ * let's try heavy test.
+ */
+ err = -EACCES;
+ if (unlikely(au_test_h_perm(h_parent->d_inode, MAY_EXEC | MAY_WRITE)))
+ goto out;
+
+ h_latest = au_sio_lkup_one(&dentry->d_name, h_parent,
+ au_sbr(dentry->d_sb, bindex));
+ err = -EIO;
+ if (IS_ERR(h_latest))
+ goto out;
+ if (h_latest == h_dentry)
+ err = 0;
+ dput(h_latest);
+
+out:
+ return err;
+}
+
+/*
+ * decide the branch where we operate for @dentry. the branch index will be set
+ * @rbcpup. after diciding it, 'pin' it and store the timestamps of the parent
+ * dir for reverting.
+ * when a new whiteout is necessary, create it.
+ */
+static struct dentry*
+lock_hdir_create_wh(struct dentry *dentry, int isdir, aufs_bindex_t *rbcpup,
+ struct au_dtime *dt, struct au_pin *pin)
+{
+ struct dentry *wh_dentry;
+ struct super_block *sb;
+ struct path h_path;
+ int err, need_wh;
+ unsigned int udba;
+ aufs_bindex_t bcpup;
+
+ need_wh = au_wr_dir_need_wh(dentry, isdir, rbcpup);
+ wh_dentry = ERR_PTR(need_wh);
+ if (unlikely(need_wh < 0))
+ goto out;
+
+ sb = dentry->d_sb;
+ udba = au_opt_udba(sb);
+ bcpup = *rbcpup;
+ err = au_pin(pin, dentry, bcpup, udba,
+ AuPin_DI_LOCKED | AuPin_MNT_WRITE);
+ wh_dentry = ERR_PTR(err);
+ if (unlikely(err))
+ goto out;
+
+ h_path.dentry = au_pinned_h_parent(pin);
+ if (udba != AuOpt_UDBA_NONE
+ && au_dbstart(dentry) == bcpup) {
+ err = au_may_del(dentry, bcpup, h_path.dentry, isdir);
+ wh_dentry = ERR_PTR(err);
+ if (unlikely(err))
+ goto out_unpin;
+ }
+
+ h_path.mnt = au_sbr_mnt(sb, bcpup);
+ au_dtime_store(dt, au_pinned_parent(pin), &h_path);
+ wh_dentry = NULL;
+ if (!need_wh)
+ goto out; /* success, no need to create whiteout */
+
+ wh_dentry = au_wh_create(dentry, bcpup, h_path.dentry);
+ if (IS_ERR(wh_dentry))
+ goto out_unpin;
+
+ /* returns with the parent is locked and wh_dentry is dget-ed */
+ goto out; /* success */
+
+out_unpin:
+ au_unpin(pin);
+out:
+ return wh_dentry;
+}
+
+/*
+ * when removing a dir, rename it to a unique temporary whiteout-ed name first
+ * in order to be revertible and save time for removing many child whiteouts
+ * under the dir.
+ * returns 1 when there are too many child whiteout and caller should remove
+ * them asynchronously. returns 0 when the number of children is enough small to
+ * remove now or the branch fs is a remote fs.
+ * otherwise return an error.
+ */
+static int renwh_and_rmdir(struct dentry *dentry, aufs_bindex_t bindex,
+ struct au_nhash *whlist, struct inode *dir)
+{
+ int rmdir_later, err, dirwh;
+ struct dentry *h_dentry;
+ struct super_block *sb;
+
+ sb = dentry->d_sb;
+ SiMustAnyLock(sb);
+ h_dentry = au_h_dptr(dentry, bindex);
+ err = au_whtmp_ren(h_dentry, au_sbr(sb, bindex));
+ if (unlikely(err))
+ goto out;
+
+ /* stop monitoring */
+ au_hn_free(au_hi(dentry->d_inode, bindex));
+
+ if (!au_test_fs_remote(h_dentry->d_sb)) {
+ dirwh = au_sbi(sb)->si_dirwh;
+ rmdir_later = (dirwh <= 1);
+ if (!rmdir_later)
+ rmdir_later = au_nhash_test_longer_wh(whlist, bindex,
+ dirwh);
+ if (rmdir_later)
+ return rmdir_later;
+ }
+
+ err = au_whtmp_rmdir(dir, bindex, h_dentry, whlist);
+ if (unlikely(err)) {
+ AuIOErr("rmdir %.*s, b%d failed, %d. ignored\n",
+ AuDLNPair(h_dentry), bindex, err);
+ err = 0;
+ }
+
+out:
+ AuTraceErr(err);
+ return err;
+}
+
+/*
+ * final procedure for deleting a entry.
+ * maintain dentry and iattr.
+ */
+static void epilog(struct inode *dir, struct dentry *dentry,
+ aufs_bindex_t bindex)
+{
+ struct inode *inode;
+
+ inode = dentry->d_inode;
+ d_drop(dentry);
+ inode->i_ctime = dir->i_ctime;
+
+ if (au_ibstart(dir) == bindex)
+ au_cpup_attr_timesizes(dir);
+ dir->i_version++;
+}
+
+/*
+ * when an error happened, remove the created whiteout and revert everything.
+ */
+static int do_revert(int err, struct inode *dir, aufs_bindex_t bindex,
+ aufs_bindex_t bwh, struct dentry *wh_dentry,
+ struct dentry *dentry, struct au_dtime *dt)
+{
+ int rerr;
+ struct path h_path = {
+ .dentry = wh_dentry,
+ .mnt = au_sbr_mnt(dir->i_sb, bindex)
+ };
+
+ rerr = au_wh_unlink_dentry(au_h_iptr(dir, bindex), &h_path, dentry);
+ if (!rerr) {
+ au_set_dbwh(dentry, bwh);
+ au_dtime_revert(dt);
+ return 0;
+ }
+
+ AuIOErr("%.*s reverting whiteout failed(%d, %d)\n",
+ AuDLNPair(dentry), err, rerr);
+ return -EIO;
+}
+
+/* ---------------------------------------------------------------------- */
+
+int aufs_unlink(struct inode *dir, struct dentry *dentry)
+{
+ int err;
+ aufs_bindex_t bwh, bindex, bstart;
+ struct au_dtime dt;
+ struct au_pin pin;
+ struct path h_path;
+ struct inode *inode, *h_dir;
+ struct dentry *parent, *wh_dentry;
+
+ IMustLock(dir);
+
+ err = aufs_read_lock(dentry, AuLock_DW | AuLock_GEN);
+ if (unlikely(err))
+ goto out;
+ err = au_d_hashed_positive(dentry);
+ if (unlikely(err))
+ goto out_unlock;
+ inode = dentry->d_inode;
+ IMustLock(inode);
+ err = -EISDIR;
+ if (unlikely(S_ISDIR(inode->i_mode)))
+ goto out_unlock; /* possible? */
+
+ bstart = au_dbstart(dentry);
+ bwh = au_dbwh(dentry);
+ bindex = -1;
+ parent = dentry->d_parent; /* dir inode is locked */
+ di_write_lock_parent(parent);
+ wh_dentry = lock_hdir_create_wh(dentry, /*isdir*/0, &bindex, &dt, &pin);
+ err = PTR_ERR(wh_dentry);
+ if (IS_ERR(wh_dentry))
+ goto out_parent;
+
+ h_path.mnt = au_sbr_mnt(dentry->d_sb, bstart);
+ h_path.dentry = au_h_dptr(dentry, bstart);
+ dget(h_path.dentry);
+ if (bindex == bstart) {
+ h_dir = au_pinned_h_dir(&pin);
+ err = vfsub_unlink(h_dir, &h_path, /*force*/0);
+ } else {
+ /* dir inode is locked */
+ h_dir = wh_dentry->d_parent->d_inode;
+ IMustLock(h_dir);
+ err = 0;
+ }
+
+ if (!err) {
+ vfsub_drop_nlink(inode);
+ epilog(dir, dentry, bindex);
+
+ /* update target timestamps */
+ if (bindex == bstart) {
+ vfsub_update_h_iattr(&h_path, /*did*/NULL); /*ignore*/
+ inode->i_ctime = h_path.dentry->d_inode->i_ctime;
+ } else
+ /* todo: this timestamp may be reverted later */
+ inode->i_ctime = h_dir->i_ctime;
+ goto out_unpin; /* success */
+ }
+
+ /* revert */
+ if (wh_dentry) {
+ int rerr;
+
+ rerr = do_revert(err, dir, bindex, bwh, wh_dentry, dentry, &dt);
+ if (rerr)
+ err = rerr;
+ }
+
+out_unpin:
+ au_unpin(&pin);
+ dput(wh_dentry);
+ dput(h_path.dentry);
+out_parent:
+ di_write_unlock(parent);
+out_unlock:
+ aufs_read_unlock(dentry, AuLock_DW);
+out:
+ return err;
+}
+
+int aufs_rmdir(struct inode *dir, struct dentry *dentry)
+{
+ int err, rmdir_later;
+ aufs_bindex_t bwh, bindex, bstart;
+ struct au_dtime dt;
+ struct au_pin pin;
+ struct inode *inode;
+ struct dentry *parent, *wh_dentry, *h_dentry;
+ struct au_whtmp_rmdir *args;
+
+ IMustLock(dir);
+
+ err = aufs_read_lock(dentry, AuLock_DW | AuLock_FLUSH | AuLock_GEN);
+ if (unlikely(err))
+ goto out;
+
+ /* VFS already unhashes it */
+ inode = dentry->d_inode;
+ err = -ENOENT;
+ if (unlikely(!inode || !inode->i_nlink
+ || IS_DEADDIR(inode)))
+ goto out_unlock;
+ IMustLock(inode);
+ err = -ENOTDIR;
+ if (unlikely(!S_ISDIR(inode->i_mode)))
+ goto out_unlock; /* possible? */
+
+ err = -ENOMEM;
+ args = au_whtmp_rmdir_alloc(dir->i_sb, GFP_NOFS);
+ if (unlikely(!args))
+ goto out_unlock;
+
+ parent = dentry->d_parent; /* dir inode is locked */
+ di_write_lock_parent(parent);
+ err = au_test_empty(dentry, &args->whlist);
+ if (unlikely(err))
+ goto out_parent;
+
+ bstart = au_dbstart(dentry);
+ bwh = au_dbwh(dentry);
+ bindex = -1;
+ wh_dentry = lock_hdir_create_wh(dentry, /*isdir*/1, &bindex, &dt, &pin);
+ err = PTR_ERR(wh_dentry);
+ if (IS_ERR(wh_dentry))
+ goto out_parent;
+
+ h_dentry = au_h_dptr(dentry, bstart);
+ dget(h_dentry);
+ rmdir_later = 0;
+ if (bindex == bstart) {
+ err = renwh_and_rmdir(dentry, bstart, &args->whlist, dir);
+ if (err > 0) {
+ rmdir_later = err;
+ err = 0;
+ }
+ } else {
+ /* stop monitoring */
+ au_hn_free(au_hi(inode, bstart));
+
+ /* dir inode is locked */
+ IMustLock(wh_dentry->d_parent->d_inode);
+ err = 0;
+ }
+
+ if (!err) {
+ vfsub_dead_dir(inode);
+ au_set_dbdiropq(dentry, -1);
+ epilog(dir, dentry, bindex);
+
+ if (rmdir_later) {
+ au_whtmp_kick_rmdir(dir, bstart, h_dentry, args);
+ args = NULL;
+ }
+
+ goto out_unpin; /* success */
+ }
+
+ /* revert */
+ AuLabel(revert);
+ if (wh_dentry) {
+ int rerr;
+
+ rerr = do_revert(err, dir, bindex, bwh, wh_dentry, dentry, &dt);
+ if (rerr)
+ err = rerr;
+ }
+
+out_unpin:
+ au_unpin(&pin);
+ dput(wh_dentry);
+ dput(h_dentry);
+out_parent:
+ di_write_unlock(parent);
+ if (args)
+ au_whtmp_rmdir_free(args);
+out_unlock:
+ aufs_read_unlock(dentry, AuLock_DW);
+out:
+ AuTraceErr(err);
+ return err;
+}
git.openpandora.org / pandora-kernel.git / blobdiff