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-rw-r--r--fs/aufs/fhsm.c426
1 files changed, 426 insertions, 0 deletions
diff --git a/fs/aufs/fhsm.c b/fs/aufs/fhsm.c
new file mode 100644
index 000000000..7ca4d1759
--- /dev/null
+++ b/fs/aufs/fhsm.c
@@ -0,0 +1,426 @@
+/*
+ * Copyright (C) 2011-2015 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
+ */
+
+/*
+ * File-based Hierarchy Storage Management
+ */
+
+#include <linux/anon_inodes.h>
+#include <linux/poll.h>
+#include <linux/seq_file.h>
+#include <linux/statfs.h>
+#include "aufs.h"
+
+static aufs_bindex_t au_fhsm_bottom(struct super_block *sb)
+{
+ struct au_sbinfo *sbinfo;
+ struct au_fhsm *fhsm;
+
+ SiMustAnyLock(sb);
+
+ sbinfo = au_sbi(sb);
+ fhsm = &sbinfo->si_fhsm;
+ AuDebugOn(!fhsm);
+ return fhsm->fhsm_bottom;
+}
+
+void au_fhsm_set_bottom(struct super_block *sb, aufs_bindex_t bindex)
+{
+ struct au_sbinfo *sbinfo;
+ struct au_fhsm *fhsm;
+
+ SiMustWriteLock(sb);
+
+ sbinfo = au_sbi(sb);
+ fhsm = &sbinfo->si_fhsm;
+ AuDebugOn(!fhsm);
+ fhsm->fhsm_bottom = bindex;
+}
+
+/* ---------------------------------------------------------------------- */
+
+static int au_fhsm_test_jiffy(struct au_sbinfo *sbinfo, struct au_branch *br)
+{
+ struct au_br_fhsm *bf;
+
+ bf = br->br_fhsm;
+ MtxMustLock(&bf->bf_lock);
+
+ return !bf->bf_readable
+ || time_after(jiffies,
+ bf->bf_jiffy + sbinfo->si_fhsm.fhsm_expire);
+}
+
+/* ---------------------------------------------------------------------- */
+
+static void au_fhsm_notify(struct super_block *sb, int val)
+{
+ struct au_sbinfo *sbinfo;
+ struct au_fhsm *fhsm;
+
+ SiMustAnyLock(sb);
+
+ sbinfo = au_sbi(sb);
+ fhsm = &sbinfo->si_fhsm;
+ if (au_fhsm_pid(fhsm)
+ && atomic_read(&fhsm->fhsm_readable) != -1) {
+ atomic_set(&fhsm->fhsm_readable, val);
+ if (val)
+ wake_up(&fhsm->fhsm_wqh);
+ }
+}
+
+static int au_fhsm_stfs(struct super_block *sb, aufs_bindex_t bindex,
+ struct aufs_stfs *rstfs, int do_lock, int do_notify)
+{
+ int err;
+ struct au_branch *br;
+ struct au_br_fhsm *bf;
+
+ br = au_sbr(sb, bindex);
+ AuDebugOn(au_br_rdonly(br));
+ bf = br->br_fhsm;
+ AuDebugOn(!bf);
+
+ if (do_lock)
+ mutex_lock(&bf->bf_lock);
+ else
+ MtxMustLock(&bf->bf_lock);
+
+ /* sb->s_root for NFS is unreliable */
+ err = au_br_stfs(br, &bf->bf_stfs);
+ if (unlikely(err)) {
+ AuErr1("FHSM failed (%d), b%d, ignored.\n", bindex, err);
+ goto out;
+ }
+
+ bf->bf_jiffy = jiffies;
+ bf->bf_readable = 1;
+ if (do_notify)
+ au_fhsm_notify(sb, /*val*/1);
+ if (rstfs)
+ *rstfs = bf->bf_stfs;
+
+out:
+ if (do_lock)
+ mutex_unlock(&bf->bf_lock);
+ au_fhsm_notify(sb, /*val*/1);
+
+ return err;
+}
+
+void au_fhsm_wrote(struct super_block *sb, aufs_bindex_t bindex, int force)
+{
+ int err;
+ struct au_sbinfo *sbinfo;
+ struct au_fhsm *fhsm;
+ struct au_branch *br;
+ struct au_br_fhsm *bf;
+
+ AuDbg("b%d, force %d\n", bindex, force);
+ SiMustAnyLock(sb);
+
+ sbinfo = au_sbi(sb);
+ fhsm = &sbinfo->si_fhsm;
+ if (!au_ftest_si(sbinfo, FHSM)
+ || fhsm->fhsm_bottom == bindex)
+ return;
+
+ br = au_sbr(sb, bindex);
+ bf = br->br_fhsm;
+ AuDebugOn(!bf);
+ mutex_lock(&bf->bf_lock);
+ if (force
+ || au_fhsm_pid(fhsm)
+ || au_fhsm_test_jiffy(sbinfo, br))
+ err = au_fhsm_stfs(sb, bindex, /*rstfs*/NULL, /*do_lock*/0,
+ /*do_notify*/1);
+ mutex_unlock(&bf->bf_lock);
+}
+
+void au_fhsm_wrote_all(struct super_block *sb, int force)
+{
+ aufs_bindex_t bindex, bend;
+ struct au_branch *br;
+
+ /* exclude the bottom */
+ bend = au_fhsm_bottom(sb);
+ for (bindex = 0; bindex < bend; bindex++) {
+ br = au_sbr(sb, bindex);
+ if (au_br_fhsm(br->br_perm))
+ au_fhsm_wrote(sb, bindex, force);
+ }
+}
+
+/* ---------------------------------------------------------------------- */
+
+static unsigned int au_fhsm_poll(struct file *file,
+ struct poll_table_struct *wait)
+{
+ unsigned int mask;
+ struct au_sbinfo *sbinfo;
+ struct au_fhsm *fhsm;
+
+ mask = 0;
+ sbinfo = file->private_data;
+ fhsm = &sbinfo->si_fhsm;
+ poll_wait(file, &fhsm->fhsm_wqh, wait);
+ if (atomic_read(&fhsm->fhsm_readable))
+ mask = POLLIN /* | POLLRDNORM */;
+
+ AuTraceErr((int)mask);
+ return mask;
+}
+
+static int au_fhsm_do_read_one(struct aufs_stbr __user *stbr,
+ struct aufs_stfs *stfs, __s16 brid)
+{
+ int err;
+
+ err = copy_to_user(&stbr->stfs, stfs, sizeof(*stfs));
+ if (!err)
+ err = __put_user(brid, &stbr->brid);
+ if (unlikely(err))
+ err = -EFAULT;
+
+ return err;
+}
+
+static ssize_t au_fhsm_do_read(struct super_block *sb,
+ struct aufs_stbr __user *stbr, size_t count)
+{
+ ssize_t err;
+ int nstbr;
+ aufs_bindex_t bindex, bend;
+ struct au_branch *br;
+ struct au_br_fhsm *bf;
+
+ /* except the bottom branch */
+ err = 0;
+ nstbr = 0;
+ bend = au_fhsm_bottom(sb);
+ for (bindex = 0; !err && bindex < bend; bindex++) {
+ br = au_sbr(sb, bindex);
+ if (!au_br_fhsm(br->br_perm))
+ continue;
+
+ bf = br->br_fhsm;
+ mutex_lock(&bf->bf_lock);
+ if (bf->bf_readable) {
+ err = -EFAULT;
+ if (count >= sizeof(*stbr))
+ err = au_fhsm_do_read_one(stbr++, &bf->bf_stfs,
+ br->br_id);
+ if (!err) {
+ bf->bf_readable = 0;
+ count -= sizeof(*stbr);
+ nstbr++;
+ }
+ }
+ mutex_unlock(&bf->bf_lock);
+ }
+ if (!err)
+ err = sizeof(*stbr) * nstbr;
+
+ return err;
+}
+
+static ssize_t au_fhsm_read(struct file *file, char __user *buf, size_t count,
+ loff_t *pos)
+{
+ ssize_t err;
+ int readable;
+ aufs_bindex_t nfhsm, bindex, bend;
+ struct au_sbinfo *sbinfo;
+ struct au_fhsm *fhsm;
+ struct au_branch *br;
+ struct super_block *sb;
+
+ err = 0;
+ sbinfo = file->private_data;
+ fhsm = &sbinfo->si_fhsm;
+need_data:
+ spin_lock_irq(&fhsm->fhsm_wqh.lock);
+ if (!atomic_read(&fhsm->fhsm_readable)) {
+ if (vfsub_file_flags(file) & O_NONBLOCK)
+ err = -EAGAIN;
+ else
+ err = wait_event_interruptible_locked_irq
+ (fhsm->fhsm_wqh,
+ atomic_read(&fhsm->fhsm_readable));
+ }
+ spin_unlock_irq(&fhsm->fhsm_wqh.lock);
+ if (unlikely(err))
+ goto out;
+
+ /* sb may already be dead */
+ au_rw_read_lock(&sbinfo->si_rwsem);
+ readable = atomic_read(&fhsm->fhsm_readable);
+ if (readable > 0) {
+ sb = sbinfo->si_sb;
+ AuDebugOn(!sb);
+ /* exclude the bottom branch */
+ nfhsm = 0;
+ bend = au_fhsm_bottom(sb);
+ for (bindex = 0; bindex < bend; bindex++) {
+ br = au_sbr(sb, bindex);
+ if (au_br_fhsm(br->br_perm))
+ nfhsm++;
+ }
+ err = -EMSGSIZE;
+ if (nfhsm * sizeof(struct aufs_stbr) <= count) {
+ atomic_set(&fhsm->fhsm_readable, 0);
+ err = au_fhsm_do_read(sbinfo->si_sb, (void __user *)buf,
+ count);
+ }
+ }
+ au_rw_read_unlock(&sbinfo->si_rwsem);
+ if (!readable)
+ goto need_data;
+
+out:
+ return err;
+}
+
+static int au_fhsm_release(struct inode *inode, struct file *file)
+{
+ struct au_sbinfo *sbinfo;
+ struct au_fhsm *fhsm;
+
+ /* sb may already be dead */
+ sbinfo = file->private_data;
+ fhsm = &sbinfo->si_fhsm;
+ spin_lock(&fhsm->fhsm_spin);
+ fhsm->fhsm_pid = 0;
+ spin_unlock(&fhsm->fhsm_spin);
+ kobject_put(&sbinfo->si_kobj);
+
+ return 0;
+}
+
+static const struct file_operations au_fhsm_fops = {
+ .owner = THIS_MODULE,
+ .llseek = noop_llseek,
+ .read = au_fhsm_read,
+ .poll = au_fhsm_poll,
+ .release = au_fhsm_release
+};
+
+int au_fhsm_fd(struct super_block *sb, int oflags)
+{
+ int err, fd;
+ struct au_sbinfo *sbinfo;
+ struct au_fhsm *fhsm;
+
+ err = -EPERM;
+ if (unlikely(!capable(CAP_SYS_ADMIN)))
+ goto out;
+
+ err = -EINVAL;
+ if (unlikely(oflags & ~(O_CLOEXEC | O_NONBLOCK)))
+ goto out;
+
+ err = 0;
+ sbinfo = au_sbi(sb);
+ fhsm = &sbinfo->si_fhsm;
+ spin_lock(&fhsm->fhsm_spin);
+ if (!fhsm->fhsm_pid)
+ fhsm->fhsm_pid = current->pid;
+ else
+ err = -EBUSY;
+ spin_unlock(&fhsm->fhsm_spin);
+ if (unlikely(err))
+ goto out;
+
+ oflags |= O_RDONLY;
+ /* oflags |= FMODE_NONOTIFY; */
+ fd = anon_inode_getfd("[aufs_fhsm]", &au_fhsm_fops, sbinfo, oflags);
+ err = fd;
+ if (unlikely(fd < 0))
+ goto out_pid;
+
+ /* succeed reglardless 'fhsm' status */
+ kobject_get(&sbinfo->si_kobj);
+ si_noflush_read_lock(sb);
+ if (au_ftest_si(sbinfo, FHSM))
+ au_fhsm_wrote_all(sb, /*force*/0);
+ si_read_unlock(sb);
+ goto out; /* success */
+
+out_pid:
+ spin_lock(&fhsm->fhsm_spin);
+ fhsm->fhsm_pid = 0;
+ spin_unlock(&fhsm->fhsm_spin);
+out:
+ AuTraceErr(err);
+ return err;
+}
+
+/* ---------------------------------------------------------------------- */
+
+int au_fhsm_br_alloc(struct au_branch *br)
+{
+ int err;
+
+ err = 0;
+ br->br_fhsm = kmalloc(sizeof(*br->br_fhsm), GFP_NOFS);
+ if (br->br_fhsm)
+ au_br_fhsm_init(br->br_fhsm);
+ else
+ err = -ENOMEM;
+
+ return err;
+}
+
+/* ---------------------------------------------------------------------- */
+
+void au_fhsm_fin(struct super_block *sb)
+{
+ au_fhsm_notify(sb, /*val*/-1);
+}
+
+void au_fhsm_init(struct au_sbinfo *sbinfo)
+{
+ struct au_fhsm *fhsm;
+
+ fhsm = &sbinfo->si_fhsm;
+ spin_lock_init(&fhsm->fhsm_spin);
+ init_waitqueue_head(&fhsm->fhsm_wqh);
+ atomic_set(&fhsm->fhsm_readable, 0);
+ fhsm->fhsm_expire
+ = msecs_to_jiffies(AUFS_FHSM_CACHE_DEF_SEC * MSEC_PER_SEC);
+ fhsm->fhsm_bottom = -1;
+}
+
+void au_fhsm_set(struct au_sbinfo *sbinfo, unsigned int sec)
+{
+ sbinfo->si_fhsm.fhsm_expire
+ = msecs_to_jiffies(sec * MSEC_PER_SEC);
+}
+
+void au_fhsm_show(struct seq_file *seq, struct au_sbinfo *sbinfo)
+{
+ unsigned int u;
+
+ if (!au_ftest_si(sbinfo, FHSM))
+ return;
+
+ u = jiffies_to_msecs(sbinfo->si_fhsm.fhsm_expire) / MSEC_PER_SEC;
+ if (u != AUFS_FHSM_CACHE_DEF_SEC)
+ seq_printf(seq, ",fhsm_sec=%u", u);
+}