Initial import

1 files changed, 738 insertions, 0 deletions

diff --git a/fs/aufs/f_op.c b/fs/aufs/f_op.c
new file mode 100644
index 000000000..34037c708
--- /dev/null
+++ b/fs/aufs/f_op.c
@@ -0,0 +1,738 @@
+/*
+ * Copyright (C) 2005-2015 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, see <http://www.gnu.org/licenses/>.
+ */
+
+/*
+ * file and vm operations
+ */
+
+#include <linux/aio.h>
+#include <linux/fs_stack.h>
+#include <linux/mman.h>
+#include <linux/security.h>
+#include "aufs.h"
+
+int au_do_open_nondir(struct file *file, int flags, struct file *h_file)
+{
+	int err;
+	aufs_bindex_t bindex;
+	struct dentry *dentry;
+	struct au_finfo *finfo;
+	struct inode *h_inode;
+
+	FiMustWriteLock(file);
+
+	err = 0;
+	dentry = file->f_path.dentry;
+	AuDebugOn(IS_ERR_OR_NULL(dentry));
+	finfo = au_fi(file);
+	memset(&finfo->fi_htop, 0, sizeof(finfo->fi_htop));
+	atomic_set(&finfo->fi_mmapped, 0);
+	bindex = au_dbstart(dentry);
+	if (!h_file)
+		h_file = au_h_open(dentry, bindex, flags, file, /*force_wr*/0);
+	else
+		get_file(h_file);
+	if (IS_ERR(h_file))
+		err = PTR_ERR(h_file);
+	else {
+		if ((flags & __O_TMPFILE)
+		    && !(flags & O_EXCL)) {
+			h_inode = file_inode(h_file);
+			spin_lock(&h_inode->i_lock);
+			h_inode->i_state |= I_LINKABLE;
+			spin_unlock(&h_inode->i_lock);
+		}
+		au_set_fbstart(file, bindex);
+		au_set_h_fptr(file, bindex, h_file);
+		au_update_figen(file);
+		/* todo: necessary? */
+		/* file->f_ra = h_file->f_ra; */
+	}
+
+	return err;
+}
+
+static int aufs_open_nondir(struct inode *inode __maybe_unused,
+			    struct file *file)
+{
+	int err;
+	struct super_block *sb;
+	struct au_do_open_args args = {
+		.open	= au_do_open_nondir
+	};
+
+	AuDbg("%pD, f_flags 0x%x, f_mode 0x%x\n",
+	      file, vfsub_file_flags(file), file->f_mode);
+
+	sb = file->f_path.dentry->d_sb;
+	si_read_lock(sb, AuLock_FLUSH);
+	err = au_do_open(file, &args);
+	si_read_unlock(sb);
+	return err;
+}
+
+int aufs_release_nondir(struct inode *inode __maybe_unused, struct file *file)
+{
+	struct au_finfo *finfo;
+	aufs_bindex_t bindex;
+
+	finfo = au_fi(file);
+	au_sphl_del(&finfo->fi_hlist,
+		    &au_sbi(file->f_path.dentry->d_sb)->si_files);
+	bindex = finfo->fi_btop;
+	if (bindex >= 0)
+		au_set_h_fptr(file, bindex, NULL);
+
+	au_finfo_fin(file);
+	return 0;
+}
+
+/* ---------------------------------------------------------------------- */
+
+static int au_do_flush_nondir(struct file *file, fl_owner_t id)
+{
+	int err;
+	struct file *h_file;
+
+	err = 0;
+	h_file = au_hf_top(file);
+	if (h_file)
+		err = vfsub_flush(h_file, id);
+	return err;
+}
+
+static int aufs_flush_nondir(struct file *file, fl_owner_t id)
+{
+	return au_do_flush(file, id, au_do_flush_nondir);
+}
+
+/* ---------------------------------------------------------------------- */
+/*
+ * read and write functions acquire [fdi]_rwsem once, but release before
+ * mmap_sem. This is because to stop a race condition between mmap(2).
+ * Releasing these aufs-rwsem should be safe, no branch-mamagement (by keeping
+ * si_rwsem), no harmful copy-up should happen. Actually copy-up may happen in
+ * read functions after [fdi]_rwsem are released, but it should be harmless.
+ */
+
+/* Callers should call au_read_post() or fput() in the end */
+struct file *au_read_pre(struct file *file, int keep_fi)
+{
+	struct file *h_file;
+	int err;
+
+	err = au_reval_and_lock_fdi(file, au_reopen_nondir, /*wlock*/0);
+	if (!err) {
+		di_read_unlock(file->f_path.dentry, AuLock_IR);
+		h_file = au_hf_top(file);
+		get_file(h_file);
+		if (!keep_fi)
+			fi_read_unlock(file);
+	} else
+		h_file = ERR_PTR(err);
+
+	return h_file;
+}
+
+static void au_read_post(struct inode *inode, struct file *h_file)
+{
+	/* update without lock, I don't think it a problem */
+	fsstack_copy_attr_atime(inode, file_inode(h_file));
+	fput(h_file);
+}
+
+struct au_write_pre {
+	blkcnt_t blks;
+	aufs_bindex_t bstart;
+};
+
+/*
+ * return with iinfo is write-locked
+ * callers should call au_write_post() or iinfo_write_unlock() + fput() in the
+ * end
+ */
+static struct file *au_write_pre(struct file *file, int do_ready,
+				 struct au_write_pre *wpre)
+{
+	struct file *h_file;
+	struct dentry *dentry;
+	int err;
+	struct au_pin pin;
+
+	err = au_reval_and_lock_fdi(file, au_reopen_nondir, /*wlock*/1);
+	h_file = ERR_PTR(err);
+	if (unlikely(err))
+		goto out;
+
+	dentry = file->f_path.dentry;
+	if (do_ready) {
+		err = au_ready_to_write(file, -1, &pin);
+		if (unlikely(err)) {
+			h_file = ERR_PTR(err);
+			di_write_unlock(dentry);
+			goto out_fi;
+		}
+	}
+
+	di_downgrade_lock(dentry, /*flags*/0);
+	if (wpre)
+		wpre->bstart = au_fbstart(file);
+	h_file = au_hf_top(file);
+	get_file(h_file);
+	if (wpre)
+		wpre->blks = file_inode(h_file)->i_blocks;
+	if (do_ready)
+		au_unpin(&pin);
+	di_read_unlock(dentry, /*flags*/0);
+
+out_fi:
+	fi_write_unlock(file);
+out:
+	return h_file;
+}
+
+static void au_write_post(struct inode *inode, struct file *h_file,
+			  struct au_write_pre *wpre, ssize_t written)
+{
+	struct inode *h_inode;
+
+	au_cpup_attr_timesizes(inode);
+	AuDebugOn(au_ibstart(inode) != wpre->bstart);
+	h_inode = file_inode(h_file);
+	inode->i_mode = h_inode->i_mode;
+	ii_write_unlock(inode);
+	fput(h_file);
+
+	/* AuDbg("blks %llu, %llu\n", (u64)blks, (u64)h_inode->i_blocks); */
+	if (written > 0)
+		au_fhsm_wrote(inode->i_sb, wpre->bstart,
+			      /*force*/h_inode->i_blocks > wpre->blks);
+}
+
+static ssize_t aufs_read(struct file *file, char __user *buf, size_t count,
+			 loff_t *ppos)
+{
+	ssize_t err;
+	struct inode *inode;
+	struct file *h_file;
+	struct super_block *sb;
+
+	inode = file_inode(file);
+	sb = inode->i_sb;
+	si_read_lock(sb, AuLock_FLUSH | AuLock_NOPLMW);
+
+	h_file = au_read_pre(file, /*keep_fi*/0);
+	err = PTR_ERR(h_file);
+	if (IS_ERR(h_file))
+		goto out;
+
+	/* filedata may be obsoleted by concurrent copyup, but no problem */
+	err = vfsub_read_u(h_file, buf, count, ppos);
+	/* todo: necessary? */
+	/* file->f_ra = h_file->f_ra; */
+	au_read_post(inode, h_file);
+
+out:
+	si_read_unlock(sb);
+	return err;
+}
+
+/*
+ * todo: very ugly
+ * it locks both of i_mutex and si_rwsem for read in safe.
+ * if the plink maintenance mode continues forever (that is the problem),
+ * may loop forever.
+ */
+static void au_mtx_and_read_lock(struct inode *inode)
+{
+	int err;
+	struct super_block *sb = inode->i_sb;
+
+	while (1) {
+		mutex_lock(&inode->i_mutex);
+		err = si_read_lock(sb, AuLock_FLUSH | AuLock_NOPLM);
+		if (!err)
+			break;
+		mutex_unlock(&inode->i_mutex);
+		si_read_lock(sb, AuLock_NOPLMW);
+		si_read_unlock(sb);
+	}
+}
+
+static ssize_t aufs_write(struct file *file, const char __user *ubuf,
+			  size_t count, loff_t *ppos)
+{
+	ssize_t err;
+	struct au_write_pre wpre;
+	struct inode *inode;
+	struct file *h_file;
+	char __user *buf = (char __user *)ubuf;
+
+	inode = file_inode(file);
+	au_mtx_and_read_lock(inode);
+
+	h_file = au_write_pre(file, /*do_ready*/1, &wpre);
+	err = PTR_ERR(h_file);
+	if (IS_ERR(h_file))
+		goto out;
+
+	err = vfsub_write_u(h_file, buf, count, ppos);
+	au_write_post(inode, h_file, &wpre, err);
+
+out:
+	si_read_unlock(inode->i_sb);
+	mutex_unlock(&inode->i_mutex);
+	return err;
+}
+
+static ssize_t au_do_iter(struct file *h_file, int rw, struct kiocb *kio,
+			  struct iov_iter *iov_iter)
+{
+	ssize_t err;
+	struct file *file;
+	ssize_t (*iter)(struct kiocb *, struct iov_iter *);
+
+	err = security_file_permission(h_file, rw);
+	if (unlikely(err))
+		goto out;
+
+	err = -ENOSYS;
+	iter = NULL;
+	if (rw == MAY_READ)
+		iter = h_file->f_op->read_iter;
+	else if (rw == MAY_WRITE)
+		iter = h_file->f_op->write_iter;
+
+	file = kio->ki_filp;
+	kio->ki_filp = h_file;
+	if (iter) {
+		lockdep_off();
+		err = iter(kio, iov_iter);
+		lockdep_on();
+	} else
+		/* currently there is no such fs */
+		WARN_ON_ONCE(1);
+	kio->ki_filp = file;
+
+out:
+	return err;
+}
+
+static ssize_t aufs_read_iter(struct kiocb *kio, struct iov_iter *iov_iter)
+{
+	ssize_t err;
+	struct file *file, *h_file;
+	struct inode *inode;
+	struct super_block *sb;
+
+	file = kio->ki_filp;
+	inode = file_inode(file);
+	sb = inode->i_sb;
+	si_read_lock(sb, AuLock_FLUSH | AuLock_NOPLMW);
+
+	h_file = au_read_pre(file, /*keep_fi*/0);
+	err = PTR_ERR(h_file);
+	if (IS_ERR(h_file))
+		goto out;
+
+	err = au_do_iter(h_file, MAY_READ, kio, iov_iter);
+	/* todo: necessary? */
+	/* file->f_ra = h_file->f_ra; */
+	au_read_post(inode, h_file);
+
+out:
+	si_read_unlock(sb);
+	return err;
+}
+
+static ssize_t aufs_write_iter(struct kiocb *kio, struct iov_iter *iov_iter)
+{
+	ssize_t err;
+	struct au_write_pre wpre;
+	struct inode *inode;
+	struct file *file, *h_file;
+
+	file = kio->ki_filp;
+	inode = file_inode(file);
+	au_mtx_and_read_lock(inode);
+
+	h_file = au_write_pre(file, /*do_ready*/1, &wpre);
+	err = PTR_ERR(h_file);
+	if (IS_ERR(h_file))
+		goto out;
+
+	err = au_do_iter(h_file, MAY_WRITE, kio, iov_iter);
+	au_write_post(inode, h_file, &wpre, err);
+
+out:
+	si_read_unlock(inode->i_sb);
+	mutex_unlock(&inode->i_mutex);
+	return err;
+}
+
+static ssize_t aufs_splice_read(struct file *file, loff_t *ppos,
+				struct pipe_inode_info *pipe, size_t len,
+				unsigned int flags)
+{
+	ssize_t err;
+	struct file *h_file;
+	struct inode *inode;
+	struct super_block *sb;
+
+	inode = file_inode(file);
+	sb = inode->i_sb;
+	si_read_lock(sb, AuLock_FLUSH | AuLock_NOPLMW);
+
+	h_file = au_read_pre(file, /*keep_fi*/1);
+	err = PTR_ERR(h_file);
+	if (IS_ERR(h_file))
+		goto out;
+
+	if (au_test_loopback_kthread()) {
+		au_warn_loopback(h_file->f_path.dentry->d_sb);
+		if (file->f_mapping != h_file->f_mapping) {
+			file->f_mapping = h_file->f_mapping;
+			smp_mb(); /* unnecessary? */
+		}
+	}
+	fi_read_unlock(file);
+
+	err = vfsub_splice_to(h_file, ppos, pipe, len, flags);
+	/* todo: necessasry? */
+	/* file->f_ra = h_file->f_ra; */
+	au_read_post(inode, h_file);
+
+out:
+	si_read_unlock(sb);
+	return err;
+}
+
+static ssize_t
+aufs_splice_write(struct pipe_inode_info *pipe, struct file *file, loff_t *ppos,
+		  size_t len, unsigned int flags)
+{
+	ssize_t err;
+	struct au_write_pre wpre;
+	struct inode *inode;
+	struct file *h_file;
+
+	inode = file_inode(file);
+	au_mtx_and_read_lock(inode);
+
+	h_file = au_write_pre(file, /*do_ready*/1, &wpre);
+	err = PTR_ERR(h_file);
+	if (IS_ERR(h_file))
+		goto out;
+
+	err = vfsub_splice_from(pipe, h_file, ppos, len, flags);
+	au_write_post(inode, h_file, &wpre, err);
+
+out:
+	si_read_unlock(inode->i_sb);
+	mutex_unlock(&inode->i_mutex);
+	return err;
+}
+
+static long aufs_fallocate(struct file *file, int mode, loff_t offset,
+			   loff_t len)
+{
+	long err;
+	struct au_write_pre wpre;
+	struct inode *inode;
+	struct file *h_file;
+
+	inode = file_inode(file);
+	au_mtx_and_read_lock(inode);
+
+	h_file = au_write_pre(file, /*do_ready*/1, &wpre);
+	err = PTR_ERR(h_file);
+	if (IS_ERR(h_file))
+		goto out;
+
+	lockdep_off();
+	err = vfs_fallocate(h_file, mode, offset, len);
+	lockdep_on();
+	au_write_post(inode, h_file, &wpre, /*written*/1);
+
+out:
+	si_read_unlock(inode->i_sb);
+	mutex_unlock(&inode->i_mutex);
+	return err;
+}
+
+/* ---------------------------------------------------------------------- */
+
+/*
+ * The locking order around current->mmap_sem.
+ * - in most and regular cases
+ *   file I/O syscall -- aufs_read() or something
+ *	-- si_rwsem for read -- mmap_sem
+ *	(Note that [fdi]i_rwsem are released before mmap_sem).
+ * - in mmap case
+ *   mmap(2) -- mmap_sem -- aufs_mmap() -- si_rwsem for read -- [fdi]i_rwsem
+ * This AB-BA order is definitly bad, but is not a problem since "si_rwsem for
+ * read" allows muliple processes to acquire it and [fdi]i_rwsem are not held in
+ * file I/O. Aufs needs to stop lockdep in aufs_mmap() though.
+ * It means that when aufs acquires si_rwsem for write, the process should never
+ * acquire mmap_sem.
+ *
+ * Actually aufs_iterate() holds [fdi]i_rwsem before mmap_sem, but this is not a
+ * problem either since any directory is not able to be mmap-ed.
+ * The similar scenario is applied to aufs_readlink() too.
+ */
+
+#if 0 /* stop calling security_file_mmap() */
+/* cf. linux/include/linux/mman.h: calc_vm_prot_bits() */
+#define AuConv_VM_PROT(f, b)	_calc_vm_trans(f, VM_##b, PROT_##b)
+
+static unsigned long au_arch_prot_conv(unsigned long flags)
+{
+	/* currently ppc64 only */
+#ifdef CONFIG_PPC64
+	/* cf. linux/arch/powerpc/include/asm/mman.h */
+	AuDebugOn(arch_calc_vm_prot_bits(-1) != VM_SAO);
+	return AuConv_VM_PROT(flags, SAO);
+#else
+	AuDebugOn(arch_calc_vm_prot_bits(-1));
+	return 0;
+#endif
+}
+
+static unsigned long au_prot_conv(unsigned long flags)
+{
+	return AuConv_VM_PROT(flags, READ)
+		| AuConv_VM_PROT(flags, WRITE)
+		| AuConv_VM_PROT(flags, EXEC)
+		| au_arch_prot_conv(flags);
+}
+
+/* cf. linux/include/linux/mman.h: calc_vm_flag_bits() */
+#define AuConv_VM_MAP(f, b)	_calc_vm_trans(f, VM_##b, MAP_##b)
+
+static unsigned long au_flag_conv(unsigned long flags)
+{
+	return AuConv_VM_MAP(flags, GROWSDOWN)
+		| AuConv_VM_MAP(flags, DENYWRITE)
+		| AuConv_VM_MAP(flags, LOCKED);
+}
+#endif
+
+static int aufs_mmap(struct file *file, struct vm_area_struct *vma)
+{
+	int err;
+	const unsigned char wlock
+		= (file->f_mode & FMODE_WRITE) && (vma->vm_flags & VM_SHARED);
+	struct super_block *sb;
+	struct file *h_file;
+	struct inode *inode;
+
+	AuDbgVmRegion(file, vma);
+
+	inode = file_inode(file);
+	sb = inode->i_sb;
+	lockdep_off();
+	si_read_lock(sb, AuLock_NOPLMW);
+
+	h_file = au_write_pre(file, wlock, /*wpre*/NULL);
+	lockdep_on();
+	err = PTR_ERR(h_file);
+	if (IS_ERR(h_file))
+		goto out;
+
+	err = 0;
+	au_set_mmapped(file);
+	au_vm_file_reset(vma, h_file);
+	/*
+	 * we cannot call security_mmap_file() here since it may acquire
+	 * mmap_sem or i_mutex.
+	 *
+	 * err = security_mmap_file(h_file, au_prot_conv(vma->vm_flags),
+	 *			 au_flag_conv(vma->vm_flags));
+	 */
+	if (!err)
+		err = h_file->f_op->mmap(h_file, vma);
+	if (!err) {
+		au_vm_prfile_set(vma, file);
+		fsstack_copy_attr_atime(inode, file_inode(h_file));
+		goto out_fput; /* success */
+	}
+	au_unset_mmapped(file);
+	au_vm_file_reset(vma, file);
+
+out_fput:
+	lockdep_off();
+	ii_write_unlock(inode);
+	lockdep_on();
+	fput(h_file);
+out:
+	lockdep_off();
+	si_read_unlock(sb);
+	lockdep_on();
+	AuTraceErr(err);
+	return err;
+}
+
+/* ---------------------------------------------------------------------- */
+
+static int aufs_fsync_nondir(struct file *file, loff_t start, loff_t end,
+			     int datasync)
+{
+	int err;
+	struct au_write_pre wpre;
+	struct inode *inode;
+	struct file *h_file;
+
+	err = 0; /* -EBADF; */ /* posix? */
+	if (unlikely(!(file->f_mode & FMODE_WRITE)))
+		goto out;
+
+	inode = file_inode(file);
+	au_mtx_and_read_lock(inode);
+
+	h_file = au_write_pre(file, /*do_ready*/1, &wpre);
+	err = PTR_ERR(h_file);
+	if (IS_ERR(h_file))
+		goto out_unlock;
+
+	err = vfsub_fsync(h_file, &h_file->f_path, datasync);
+	au_write_post(inode, h_file, &wpre, /*written*/0);
+
+out_unlock:
+	si_read_unlock(inode->i_sb);
+	mutex_unlock(&inode->i_mutex);
+out:
+	return err;
+}
+
+/* no one supports this operation, currently */
+#if 0
+static int aufs_aio_fsync_nondir(struct kiocb *kio, int datasync)
+{
+	int err;
+	struct au_write_pre wpre;
+	struct inode *inode;
+	struct file *file, *h_file;
+
+	err = 0; /* -EBADF; */ /* posix? */
+	if (unlikely(!(file->f_mode & FMODE_WRITE)))
+		goto out;
+
+	file = kio->ki_filp;
+	inode = file_inode(file);
+	au_mtx_and_read_lock(inode);
+
+	h_file = au_write_pre(file, /*do_ready*/1, &wpre);
+	err = PTR_ERR(h_file);
+	if (IS_ERR(h_file))
+		goto out_unlock;
+
+	err = -ENOSYS;
+	h_file = au_hf_top(file);
+	if (h_file->f_op->aio_fsync) {
+		struct mutex *h_mtx;
+
+		h_mtx = &file_inode(h_file)->i_mutex;
+		if (!is_sync_kiocb(kio)) {
+			get_file(h_file);
+			fput(file);
+		}
+		kio->ki_filp = h_file;
+		err = h_file->f_op->aio_fsync(kio, datasync);
+		mutex_lock_nested(h_mtx, AuLsc_I_CHILD);
+		if (!err)
+			vfsub_update_h_iattr(&h_file->f_path, /*did*/NULL);
+		/*ignore*/
+		mutex_unlock(h_mtx);
+	}
+	au_write_post(inode, h_file, &wpre, /*written*/0);
+
+out_unlock:
+	si_read_unlock(inode->sb);
+	mutex_unlock(&inode->i_mutex);
+out:
+	return err;
+}
+#endif
+
+static int aufs_fasync(int fd, struct file *file, int flag)
+{
+	int err;
+	struct file *h_file;
+	struct super_block *sb;
+
+	sb = file->f_path.dentry->d_sb;
+	si_read_lock(sb, AuLock_FLUSH | AuLock_NOPLMW);
+
+	h_file = au_read_pre(file, /*keep_fi*/0);
+	err = PTR_ERR(h_file);
+	if (IS_ERR(h_file))
+		goto out;
+
+	if (h_file->f_op->fasync)
+		err = h_file->f_op->fasync(fd, h_file, flag);
+	fput(h_file); /* instead of au_read_post() */
+
+out:
+	si_read_unlock(sb);
+	return err;
+}
+
+/* ---------------------------------------------------------------------- */
+
+/* no one supports this operation, currently */
+#if 0
+static ssize_t aufs_sendpage(struct file *file, struct page *page, int offset,
+			     size_t len, loff_t *pos, int more)
+{
+}
+#endif
+
+/* ---------------------------------------------------------------------- */
+
+const struct file_operations aufs_file_fop = {
+	.owner		= THIS_MODULE,
+
+	.llseek		= default_llseek,
+
+	.read		= aufs_read,
+	.write		= aufs_write,
+	.read_iter	= aufs_read_iter,
+	.write_iter	= aufs_write_iter,
+
+#ifdef CONFIG_AUFS_POLL
+	.poll		= aufs_poll,
+#endif
+	.unlocked_ioctl	= aufs_ioctl_nondir,
+#ifdef CONFIG_COMPAT
+	.compat_ioctl	= aufs_compat_ioctl_nondir,
+#endif
+	.mmap		= aufs_mmap,
+	.open		= aufs_open_nondir,
+	.flush		= aufs_flush_nondir,
+	.release	= aufs_release_nondir,
+	.fsync		= aufs_fsync_nondir,
+	/* .aio_fsync	= aufs_aio_fsync_nondir, */
+	.fasync		= aufs_fasync,
+	/* .sendpage	= aufs_sendpage, */
+	.splice_write	= aufs_splice_write,
+	.splice_read	= aufs_splice_read,
+#if 0
+	.aio_splice_write = aufs_aio_splice_write,
+	.aio_splice_read  = aufs_aio_splice_read,
+#endif
+	.fallocate	= aufs_fallocate
+};