[AUFS PATCH v2.6.26-rc2-mm1 21/39] aufs file (vm op)

[hooanon05]

From: Junjiro Okajima <hooanon05@xxxxxxxxxxx>

initial commit
file operations and vm operations

Signed-off-by: Junjiro Okajima <hooanon05@xxxxxxxxxxx>
---
 fs/aufs/f_op.c |  645 ++++++++++++++++++++++++++++++++++++++++++++++++++++++++
 1 files changed, 645 insertions(+), 0 deletions(-)
 create mode 100644 fs/aufs/f_op.c

diff --git a/fs/aufs/f_op.c b/fs/aufs/f_op.c
new file mode 100644
index 0000000..cf48f45
--- /dev/null
+++ b/fs/aufs/f_op.c
@@ -0,0 +1,645 @@
+/*
+ * Copyright (C) 2005-2008 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
+ */
+
+/*
+ * file and vm operations
+ */
+
+#include <linux/fs_stack.h>
+#include <linux/poll.h>
+#include "aufs.h"
+
+/* common function to regular file and dir */
+int aufs_flush(struct file *file, fl_owner_t id)
+{
+	int err;
+	struct dentry *dentry;
+	aufs_bindex_t bindex, bend;
+
+	dentry = file->f_dentry;
+	LKTRTrace("%.*s\n", AuDLNPair(dentry));
+
+	si_noflush_read_lock(dentry->d_sb);
+	fi_read_lock(file);
+	di_read_lock_child(dentry, AuLock_IW);
+
+	err = 0;
+	bend = au_fbend(file);
+	for (bindex = au_fbstart(file); !err && bindex <= bend; bindex++) {
+		struct file *h_file;
+		h_file = au_h_fptr(file, bindex);
+		if (h_file && h_file->f_op && h_file->f_op->flush) {
+			err = h_file->f_op->flush(h_file, id);
+			if (!err)
+				au_update_fuse_h_inode
+					(h_file->f_vfsmnt, h_file->f_dentry);
+			/*ignore*/
+		}
+	}
+	au_cpup_attr_timesizes(dentry->d_inode);
+
+	di_read_unlock(dentry, AuLock_IW);
+	fi_read_unlock(file);
+	si_read_unlock(dentry->d_sb);
+	AuTraceErr(err);
+	return err;
+}
+
+/* ---------------------------------------------------------------------- */
+
+static int do_open_nondir(struct file *file, int flags)
+{
+	int err;
+	aufs_bindex_t bindex;
+	struct super_block *sb;
+	struct file *h_file;
+	struct dentry *dentry;
+	struct inode *inode;
+	struct au_finfo *finfo;
+
+	dentry = file->f_dentry;
+	LKTRTrace("%.*s, flags 0%o\n", AuDLNPair(dentry), flags);
+	FiMustWriteLock(file);
+	inode = dentry->d_inode;
+	AuDebugOn(!inode || S_ISDIR(inode->i_mode));
+
+	err = 0;
+	finfo = au_fi(file);
+	finfo->fi_h_vm_ops = NULL;
+	sb = dentry->d_sb;
+	bindex = au_dbstart(dentry);
+	AuDebugOn(!au_h_dptr(dentry, bindex)->d_inode);
+	/* O_TRUNC is processed already */
+	BUG_ON(au_test_ro(sb, bindex, inode) && (flags & O_TRUNC));
+
+	h_file = au_h_open(dentry, bindex, flags, file);
+	if (!IS_ERR(h_file)) {
+		au_set_fbstart(file, bindex);
+		au_set_fbend(file, bindex);
+		au_set_h_fptr(file, bindex, h_file);
+		au_update_figen(file);
+		/* todo: necessary? */
+		/* file->f_ra = h_file->f_ra; */
+		return 0; /* success */
+	}
+	err = PTR_ERR(h_file);
+	AuTraceErr(err);
+	return err;
+}
+
+static int aufs_open_nondir(struct inode *inode, struct file *file)
+{
+	return au_do_open(inode, file, do_open_nondir);
+}
+
+static int aufs_release_nondir(struct inode *inode, struct file *file)
+{
+	struct super_block *sb = file->f_dentry->d_sb;
+
+	LKTRTrace("i%lu, %.*s\n", inode->i_ino, AuDLNPair(file->f_dentry));
+
+	si_noflush_read_lock(sb);
+	au_finfo_fin(file);
+	si_read_unlock(sb);
+	return 0;
+}
+
+/* ---------------------------------------------------------------------- */
+
+static ssize_t aufs_read(struct file *file, char __user *buf, size_t count,
+			 loff_t *ppos)
+{
+	ssize_t err;
+	struct dentry *dentry;
+	struct file *h_file;
+	struct super_block *sb;
+	struct inode *h_inode;
+
+	dentry = file->f_dentry;
+	LKTRTrace("%.*s, cnt %lu, pos %Ld\n",
+		  AuDLNPair(dentry), (unsigned long)count, *ppos);
+
+	sb = dentry->d_sb;
+	si_read_lock(sb, AuLock_FLUSH);
+	err = au_reval_and_lock_finfo(file, au_reopen_nondir, /*wlock*/0,
+				      /*locked*/0);
+	if (unlikely(err))
+		goto out;
+
+	/* support LSM and notify */
+	h_file = au_h_fptr(file, au_fbstart(file));
+	h_inode = h_file->f_dentry->d_inode;
+	err = vfsub_read_u(h_file, buf, count, ppos,
+			   au_opt_test_dlgt(au_mntflags(sb)));
+	/* todo: necessary? */
+	/* file->f_ra = h_file->f_ra; */
+	fsstack_copy_attr_atime(dentry->d_inode, h_file->f_dentry->d_inode);
+
+	fi_read_unlock(file);
+ out:
+	si_read_unlock(sb);
+	AuTraceErr(err);
+	return err;
+}
+
+static ssize_t aufs_write(struct file *file, const char __user *ubuf,
+			  size_t count, loff_t *ppos)
+{
+	ssize_t err;
+	struct dentry *dentry, *parent;
+	struct inode *inode, *dir;
+	struct super_block *sb;
+	unsigned int mnt_flags;
+	struct file *h_file;
+	char __user *buf = (char __user *)ubuf;
+	struct au_hin_ignore ign;
+	struct vfsub_args vargs;
+
+	dentry = file->f_dentry;
+	LKTRTrace("%.*s, cnt %lu, pos %Ld\n",
+		  AuDLNPair(dentry), (unsigned long)count, *ppos);
+
+	inode = dentry->d_inode;
+	mutex_lock(&inode->i_mutex);
+	sb = dentry->d_sb;
+	si_read_lock(sb, AuLock_FLUSH);
+	err = au_reval_and_lock_finfo(file, au_reopen_nondir, /*wlock*/1,
+				      /*locked*/1);
+	if (unlikely(err))
+		goto out;
+	err = au_ready_to_write(file, -1);
+	if (unlikely(err))
+		goto out_unlock;
+
+	/* support LSM and notify */
+	mnt_flags = au_mntflags(sb);
+	vfsub_args_init(&vargs, &ign, au_opt_test_dlgt(mnt_flags), 0);
+	h_file = au_h_fptr(file, au_fbstart(file));
+	if (!au_opt_test(mnt_flags, UDBA_INOTIFY))
+		err = vfsub_write_u(h_file, buf, count, ppos, &vargs);
+	else {
+		parent = dget_parent(dentry);
+		dir = parent->d_inode;
+		ii_read_lock_parent(dir);
+		vfsub_ign_hinode(&vargs, IN_MODIFY,
+				 au_hi(dir, au_fbstart(file)));
+		err = vfsub_write_u(h_file, buf, count, ppos, &vargs);
+		ii_read_unlock(dir);
+		dput(parent);
+	}
+	ii_write_lock_child(inode);
+	au_cpup_attr_timesizes(inode);
+	ii_write_unlock(inode);
+
+ out_unlock:
+	fi_write_unlock(file);
+ out:
+	si_read_unlock(sb);
+	mutex_unlock(&inode->i_mutex);
+	AuTraceErr(err);
+	return err;
+}
+
+static int au_test_loopback(void)
+{
+	const char c = current->comm[4];
+	/* true if a kernel thread named 'loop[0-9].*' accesses a file */
+	const int loopback = (current->mm == NULL
+			      && '0' <= c && c <= '9'
+			      && strncmp(current->comm, "loop", 4) == 0);
+	return loopback;
+}
+
+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 dentry *dentry;
+	struct super_block *sb;
+
+	dentry = file->f_dentry;
+	LKTRTrace("%.*s, pos %Ld, len %lu\n",
+		  AuDLNPair(dentry), *ppos, (unsigned long)len);
+
+	sb = dentry->d_sb;
+	si_read_lock(sb, AuLock_FLUSH);
+	err = au_reval_and_lock_finfo(file, au_reopen_nondir, /*wlock*/0,
+				      /*locked*/0);
+	if (unlikely(err))
+		goto out;
+
+	err = -EINVAL;
+	/* support LSM and notify */
+	h_file = au_h_fptr(file, au_fbstart(file));
+	if (/* unlikely */(au_test_loopback())) {
+		file->f_mapping = h_file->f_mapping;
+		smp_mb(); /* unnecessary? */
+	}
+	err = vfsub_splice_to(h_file, ppos, pipe, len, flags,
+			      au_opt_test_dlgt(au_mntflags(sb)));
+	/* todo: necessasry? */
+	/* file->f_ra = h_file->f_ra; */
+	fsstack_copy_attr_atime(dentry->d_inode, h_file->f_dentry->d_inode);
+	fi_read_unlock(file);
+
+ out:
+	si_read_unlock(sb);
+	AuTraceErr(err);
+	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 dentry *dentry;
+	struct inode *inode, *h_inode;
+	struct super_block *sb;
+	struct file *h_file;
+	struct au_hin_ignore ign;
+	struct vfsub_args vargs;
+	unsigned int mnt_flags;
+
+	dentry = file->f_dentry;
+	LKTRTrace("%.*s, len %lu, pos %Ld\n",
+		  AuDLNPair(dentry), (unsigned long)len, *ppos);
+
+	inode = dentry->d_inode;
+	mutex_lock(&inode->i_mutex);
+	sb = dentry->d_sb;
+	si_read_lock(sb, AuLock_FLUSH);
+	err = au_reval_and_lock_finfo(file, au_reopen_nondir, /*wlock*/1,
+				      /*locked*/1);
+	if (unlikely(err))
+		goto out;
+	err = au_ready_to_write(file, -1);
+	if (unlikely(err))
+		goto out_unlock;
+
+	/* support LSM and notify */
+	mnt_flags = au_mntflags(sb);
+	vfsub_args_init(&vargs, &ign, au_opt_test_dlgt(mnt_flags), 0);
+	h_file = au_h_fptr(file, au_fbstart(file));
+	h_inode = h_file->f_dentry->d_inode;
+	/* current do_splice_from() doesn't fire up the inotify event */
+	if (1 || !au_opt_test(mnt_flags, UDBA_INOTIFY))
+		err = vfsub_splice_from(pipe, h_file, ppos, len, flags, &vargs);
+#if 0 /* reserved for future use */
+	else {
+		struct dentry *parent = dget_parent(dentry);
+		vfsub_ign_hinode(&vargs, IN_MODIFY,
+		au_hi(parent->d_inode, au_fbstart(file));
+		err = vfsub_splice_from(pipe, h_file, ppos, len, flags, &vargs);
+		dput(parent);
+	}
+#endif
+	ii_write_lock_child(inode);
+	au_cpup_attr_timesizes(inode);
+	ii_write_unlock(inode);
+
+ out_unlock:
+	fi_write_unlock(file);
+ out:
+	si_read_unlock(sb);
+	mutex_unlock(&inode->i_mutex);
+	AuTraceErr(err);
+	return err;
+}
+
+/* ---------------------------------------------------------------------- */
+
+static int aufs_fault(struct vm_area_struct *vma, struct vm_fault *vmf)
+{
+	int err;
+	struct dentry *dentry;
+	struct file *file, *h_file;
+	struct inode *inode;
+	static DECLARE_WAIT_QUEUE_HEAD(wq);
+	struct au_finfo *finfo;
+
+	AuTraceEnter();
+	AuDebugOn(!vma || !vma->vm_file);
+	/* todo: non-robr mode, user vm_file as it is? */
+	wait_event(wq, (file = au_robr_safe_file(vma)));
+	AuDebugOn(!au_test_aufs(file->f_dentry->d_sb));
+	dentry = file->f_dentry;
+	LKTRTrace("%.*s\n", AuDLNPair(dentry));
+	inode = dentry->d_inode;
+	AuDebugOn(!S_ISREG(inode->i_mode));
+
+	/* do not revalidate, no si lock */
+	finfo = au_fi(file);
+	h_file = finfo->fi_hfile[0 + finfo->fi_bstart].hf_file;
+	AuDebugOn(!h_file || !au_test_mmapped(file));
+	fi_write_lock(file);
+	vma->vm_file = h_file;
+	err = finfo->fi_h_vm_ops->fault(vma, vmf);
+	/* todo: necessary? */
+	/* file->f_ra = h_file->f_ra; */
+	au_robr_reset_file(vma, file);
+	fi_write_unlock(file);
+#if 0 /* def CONFIG_SMP */
+	/* wake_up_nr(&wq, online_cpu - 1); */
+	wake_up_all(&wq);
+#else
+	wake_up(&wq);
+#endif
+
+	if (!(err & VM_FAULT_ERROR)) {
+#if 0 /* debug */
+		struct page *page;
+		page = vmf->page;
+		AuDbg("%p, %d\n", page, page_mapcount(page));
+
+		page->mapping = file->f_mapping;
+		get_page(page);
+		file->f_mapping = h_file->f_mapping;
+		touch_atime(NULL, dentry);
+		inode->i_atime = h_file->f_dentry->d_inode->i_atime;
+#endif
+	}
+	AuTraceErr(err);
+	return err;
+}
+
+static struct vm_operations_struct aufs_vm_ops = {
+	.fault		= aufs_fault,
+#if 0 /* reserved for future use */
+	.open		= aufs_vmaopen,
+	.close		= aufs_vmaclose,
+	unsigned long (*nopfn)(struct vm_area_struct *area,
+			       unsigned long address);
+	page_mkwrite(struct vm_area_struct *vma, struct page *page)
+#endif
+};
+
+/* ---------------------------------------------------------------------- */
+
+static struct vm_operations_struct *au_vm_ops(struct file *h_file,
+					      struct vm_area_struct *vma)
+{
+	struct vm_operations_struct *vm_ops;
+	int err;
+
+	AuTraceEnter();
+
+	if (!au_test_nfs(h_file->f_vfsmnt->mnt_sb))
+		err = h_file->f_op->mmap(h_file, vma);
+	else {
+		lockdep_off();
+		err = h_file->f_op->mmap(h_file, vma);
+		lockdep_on();
+	}
+	vm_ops = ERR_PTR(err);
+	if (unlikely(err))
+		goto out;
+	vm_ops = vma->vm_ops;
+	err = do_munmap(current->mm, vma->vm_start,
+			vma->vm_end - vma->vm_start);
+	if (unlikely(err)) {
+		AuIOErr("failed internal unmapping %.*s, %d\n",
+			AuDLNPair(h_file->f_dentry), err);
+		vm_ops = ERR_PTR(-EIO);
+	}
+
+ out:
+	AuTraceErrPtr(vm_ops);
+	return vm_ops;
+}
+
+static int aufs_mmap(struct file *file, struct vm_area_struct *vma)
+{
+	int err, wlock, mmapped;
+	struct dentry *dentry;
+	struct super_block *sb;
+	struct file *h_file;
+	struct vm_operations_struct *vm_ops;
+
+	dentry = file->f_dentry;
+	LKTRTrace("%.*s, %lx, len %lu\n",
+		  AuDLNPair(dentry), vma->vm_start,
+		  vma->vm_end - vma->vm_start);
+	AuDebugOn(!S_ISREG(dentry->d_inode->i_mode));
+	AuDebugOn(down_write_trylock(&vma->vm_mm->mmap_sem));
+
+	mmapped = au_test_mmapped(file); /* can be harmless race condition */
+	wlock = !!(file->f_mode & FMODE_WRITE);
+	sb = dentry->d_sb;
+	si_read_lock(sb, AuLock_FLUSH);
+	err = au_reval_and_lock_finfo(file, au_reopen_nondir,
+				      wlock | !mmapped, /*locked*/0);
+	if (unlikely(err))
+		goto out;
+
+	if (wlock) {
+		err = au_ready_to_write(file, -1);
+		if (unlikely(err))
+			goto out_unlock;
+	}
+
+	h_file = au_h_fptr(file, au_fbstart(file));
+	if (unlikely(au_test_fuse(h_file->f_dentry->d_sb))) {
+		/*
+		 * by this assignment, f_mapping will differs from aufs inode
+		 * i_mapping.
+		 * if someone else mixes the use of f_dentry->d_inode and
+		 * f_mapping->host, then a problem may arise.
+		 */
+		file->f_mapping = h_file->f_mapping;
+	}
+
+	if (0 && h_file->f_op->mmap == generic_file_mmap) {
+		err = generic_file_mmap(file, vma); /* instead of h_file */
+		if (unlikely(err))
+			goto out_unlock;
+		au_fi(file)->fi_h_vm_ops = vma->vm_ops;
+	} else {
+		vm_ops = NULL;
+		if (!mmapped) {
+			vm_ops = au_vm_ops(h_file, vma);
+			err = PTR_ERR(vm_ops);
+			if (IS_ERR(vm_ops))
+				goto out_unlock;
+		}
+
+		err = generic_file_mmap(file, vma);
+		if (unlikely(err))
+			goto out_unlock;
+		vma->vm_ops = &aufs_vm_ops;
+		/* test again */
+		if (!au_test_mmapped(file)) {
+			FiMustWriteLock(file);
+			au_fi(file)->fi_h_vm_ops = vm_ops;
+		}
+	}
+
+	file_accessed(h_file);
+	au_update_fuse_h_inode(h_file->f_vfsmnt, h_file->f_dentry); /*ignore*/
+	fsstack_copy_attr_atime(dentry->d_inode, h_file->f_dentry->d_inode);
+
+ out_unlock:
+	if (!wlock && mmapped)
+		fi_read_unlock(file);
+	else
+		fi_write_unlock(file);
+ out:
+	si_read_unlock(sb);
+	AuTraceErr(err);
+	return err;
+}
+
+/* ---------------------------------------------------------------------- */
+
+static unsigned int aufs_poll(struct file *file, poll_table *wait)
+{
+	unsigned int mask;
+	struct file *h_file;
+	int err;
+	struct dentry *dentry;
+	struct super_block *sb;
+
+	dentry = file->f_dentry;
+	LKTRTrace("%.*s, wait %p\n", AuDLNPair(dentry), wait);
+	AuDebugOn(S_ISDIR(dentry->d_inode->i_mode));
+
+	/* We should pretend an error happened. */
+	mask = POLLERR /* | POLLIN | POLLOUT */;
+	sb = dentry->d_sb;
+	si_read_lock(sb, AuLock_FLUSH);
+	err = au_reval_and_lock_finfo(file, au_reopen_nondir, /*wlock*/0,
+				      /*locked*/0);
+	if (unlikely(err))
+		goto out;
+
+	/* it is not an error of hidden_file has no operation */
+	mask = DEFAULT_POLLMASK;
+	h_file = au_h_fptr(file, au_fbstart(file));
+	if (h_file->f_op && h_file->f_op->poll)
+		mask = h_file->f_op->poll(h_file, wait);
+	fi_read_unlock(file);
+
+ out:
+	si_read_unlock(sb);
+	AuTraceErr((int)mask);
+	return mask;
+}
+
+static int aufs_fsync_nondir(struct file *file, struct dentry *dentry,
+			     int datasync)
+{
+	int err;
+	struct inode *inode;
+	struct file *h_file;
+	struct super_block *sb;
+
+	LKTRTrace("%.*s, %d\n", AuDLNPair(dentry), datasync);
+	inode = dentry->d_inode;
+
+	IMustLock(file->f_mapping->host);
+	if (unlikely(inode != file->f_mapping->host)) {
+		mutex_unlock(&file->f_mapping->host->i_mutex);
+		mutex_lock(&inode->i_mutex);
+	}
+	IMustLock(inode);
+
+	sb = dentry->d_sb;
+	si_read_lock(sb, AuLock_FLUSH);
+	err = 0; /* -EBADF; */ /* posix? */
+	if (unlikely(!(file->f_mode & FMODE_WRITE)))
+		goto out;
+	err = au_reval_and_lock_finfo(file, au_reopen_nondir, /*wlock*/1,
+				      /*locked*/1);
+	if (unlikely(err))
+		goto out;
+	err = au_ready_to_write(file, -1);
+	if (unlikely(err))
+		goto out_unlock;
+
+	err = -EINVAL;
+	h_file = au_h_fptr(file, au_fbstart(file));
+	if (h_file->f_op && h_file->f_op->fsync) {
+		ii_write_lock_child(inode);
+		mutex_lock_nested(&h_file->f_dentry->d_inode->i_mutex,
+				  AuLsc_I_CHILD);
+		err = h_file->f_op->fsync(h_file, h_file->f_dentry, datasync);
+		if (!err)
+			au_update_fuse_h_inode(h_file->f_vfsmnt,
+					       h_file->f_dentry);
+		au_cpup_attr_timesizes(inode);
+		mutex_unlock(&h_file->f_dentry->d_inode->i_mutex);
+		ii_write_unlock(inode);
+	}
+
+ out_unlock:
+	fi_write_unlock(file);
+ out:
+	si_read_unlock(sb);
+	if (unlikely(inode != file->f_mapping->host)) {
+		mutex_unlock(&inode->i_mutex);
+		mutex_lock(&file->f_mapping->host->i_mutex);
+	}
+	AuTraceErr(err);
+	return err;
+}
+
+static int aufs_fasync(int fd, struct file *file, int flag)
+{
+	int err;
+	struct file *h_file;
+	struct dentry *dentry;
+	struct super_block *sb;
+
+	dentry = file->f_dentry;
+	LKTRTrace("%.*s, %d\n", AuDLNPair(dentry), flag);
+
+	sb = dentry->d_sb;
+	si_read_lock(sb, AuLock_FLUSH);
+	err = au_reval_and_lock_finfo(file, au_reopen_nondir, /*wlock*/0,
+				      /*locked*/0);
+	if (unlikely(err))
+		goto out;
+
+	h_file = au_h_fptr(file, au_fbstart(file));
+	if (h_file->f_op && h_file->f_op->fasync)
+		err = h_file->f_op->fasync(fd, h_file, flag);
+	fi_read_unlock(file);
+
+ out:
+	si_read_unlock(sb);
+	AuTraceErr(err);
+	return err;
+}
+
+/* ---------------------------------------------------------------------- */
+
+struct file_operations aufs_file_fop = {
+	.read		= aufs_read,
+	.write		= aufs_write,
+	.poll		= aufs_poll,
+	.mmap		= aufs_mmap,
+	.open		= aufs_open_nondir,
+	.flush		= aufs_flush,
+	.release	= aufs_release_nondir,
+	.fsync		= aufs_fsync_nondir,
+	.fasync		= aufs_fasync,
+	.splice_write	= aufs_splice_write,
+	.splice_read	= aufs_splice_read,
+};
-- 
1.5.5.1.308.g1fbb5.dirty

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