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9P: introduction of a new cache=mmap model. 

- Add cache=mmap option
 - Make mmap read-write while keeping it as synchronous as possible
 - Build writeback fid on mmap creation if it is writable

Signed-off-by: Dominique Martinet <dominique.martinet@cea.fr>
Signed-off-by: Eric Van Hensbergen <ericvh@gmail.com>
hifive-unleashed-5.1
Dominique Martinet 2014-01-10 13:44:09 +01:00 committed by Eric Van Hensbergen
parent f94741fd28
commit fb89b45cdf
8 changed files with 179 additions and 19 deletions
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9
fs/9p/v9fs.c
View File

@ -56,7 +56,7 @@ enum {
/* Options that take no arguments */
Opt_nodevmap,
/* Cache options */
Opt_cache_loose, Opt_fscache,
Opt_cache_loose, Opt_fscache, Opt_mmap,
/* Access options */
Opt_access, Opt_posixacl,
/* Error token */
@ -74,6 +74,7 @@ static const match_table_t tokens = {
{Opt_cache, "cache=%s"},
{Opt_cache_loose, "loose"},
{Opt_fscache, "fscache"},
{Opt_mmap, "mmap"},
{Opt_cachetag, "cachetag=%s"},
{Opt_access, "access=%s"},
{Opt_posixacl, "posixacl"},
@ -91,6 +92,9 @@ static int get_cache_mode(char *s)
} else if (!strcmp(s, "fscache")) {
version = CACHE_FSCACHE;
p9_debug(P9_DEBUG_9P, "Cache mode: fscache\n");
} else if (!strcmp(s, "mmap")) {
version = CACHE_MMAP;
p9_debug(P9_DEBUG_9P, "Cache mode: mmap\n");
} else if (!strcmp(s, "none")) {
version = CACHE_NONE;
p9_debug(P9_DEBUG_9P, "Cache mode: none\n");
@ -220,6 +224,9 @@ static int v9fs_parse_options(struct v9fs_session_info *v9ses, char *opts)
case Opt_fscache:
v9ses->cache = CACHE_FSCACHE;
break;
case Opt_mmap:
v9ses->cache = CACHE_MMAP;
break;
case Opt_cachetag:
#ifdef CONFIG_9P_FSCACHE
v9ses->cachetag = match_strdup(&args[0]);

1
fs/9p/v9fs.h
View File

@ -64,6 +64,7 @@ enum p9_session_flags {
enum p9_cache_modes {
CACHE_NONE,
CACHE_MMAP,
CACHE_LOOSE,
CACHE_FSCACHE,
};

2
fs/9p/v9fs_vfs.h
View File

@ -50,6 +50,8 @@ extern const struct dentry_operations v9fs_dentry_operations;
extern const struct dentry_operations v9fs_cached_dentry_operations;
extern const struct file_operations v9fs_cached_file_operations;
extern const struct file_operations v9fs_cached_file_operations_dotl;
extern const struct file_operations v9fs_mmap_file_operations;
extern const struct file_operations v9fs_mmap_file_operations_dotl;
extern struct kmem_cache *v9fs_inode_cache;
struct inode *v9fs_alloc_inode(struct super_block *sb);

7
fs/9p/vfs_addr.c
View File

@ -202,6 +202,8 @@ static int v9fs_vfs_writepage(struct page *page, struct writeback_control *wbc)
{
int retval;
p9_debug(P9_DEBUG_VFS, "page %p\n", page);
retval = v9fs_vfs_writepage_locked(page);
if (retval < 0) {
if (retval == -EAGAIN) {
@ -282,6 +284,9 @@ static int v9fs_write_begin(struct file *filp, struct address_space *mapping,
pgoff_t index = pos >> PAGE_CACHE_SHIFT;
struct inode *inode = mapping->host;
p9_debug(P9_DEBUG_VFS, "filp %p, mapping %p\n", filp, mapping);
v9inode = V9FS_I(inode);
start:
page = grab_cache_page_write_begin(mapping, index, flags);
@ -312,6 +317,8 @@ static int v9fs_write_end(struct file *filp, struct address_space *mapping,
loff_t last_pos = pos + copied;
struct inode *inode = page->mapping->host;
p9_debug(P9_DEBUG_VFS, "filp %p, mapping %p\n", filp, mapping);
if (unlikely(copied < len)) {
/*
* zero out the rest of the area

140
fs/9p/vfs_file.c
View File

@ -45,6 +45,7 @@
#include "cache.h"
static const struct vm_operations_struct v9fs_file_vm_ops;
static const struct vm_operations_struct v9fs_mmap_file_vm_ops;
/**
* v9fs_file_open - open a file (or directory)
@ -87,7 +88,8 @@ int v9fs_file_open(struct inode *inode, struct file *file)
file->private_data = fid;
mutex_lock(&v9inode->v_mutex);
if (v9ses->cache && !v9inode->writeback_fid &&
if ((v9ses->cache == CACHE_LOOSE || v9ses->cache == CACHE_FSCACHE) &&
!v9inode->writeback_fid &&
((file->f_flags & O_ACCMODE) != O_RDONLY)) {
/*
* clone a fid and add it to writeback_fid
@ -105,7 +107,7 @@ int v9fs_file_open(struct inode *inode, struct file *file)
v9inode->writeback_fid = (void *) fid;
}
mutex_unlock(&v9inode->v_mutex);
if (v9ses->cache)
if (v9ses->cache == CACHE_LOOSE || v9ses->cache == CACHE_FSCACHE)
v9fs_cache_inode_set_cookie(inode, file);
return 0;
out_error:
@ -579,17 +581,55 @@ int v9fs_file_fsync_dotl(struct file *filp, loff_t start, loff_t end,
}
static int
v9fs_file_mmap(struct file *file, struct vm_area_struct *vma)
v9fs_file_mmap(struct file *filp, struct vm_area_struct *vma)
{
int retval;
retval = generic_file_mmap(file, vma);
retval = generic_file_mmap(filp, vma);
if (!retval)
vma->vm_ops = &v9fs_file_vm_ops;
return retval;
}
static int
v9fs_mmap_file_mmap(struct file *filp, struct vm_area_struct *vma)
{
int retval;
struct inode *inode;
struct v9fs_inode *v9inode;
struct p9_fid *fid;
inode = file_inode(filp);
v9inode = V9FS_I(inode);
mutex_lock(&v9inode->v_mutex);
if (!v9inode->writeback_fid &&
(vma->vm_flags & VM_WRITE)) {
/*
* clone a fid and add it to writeback_fid
* we do it during mmap instead of
* page dirty time via write_begin/page_mkwrite
* because we want write after unlink usecase
* to work.
*/
fid = v9fs_writeback_fid(filp->f_path.dentry);
if (IS_ERR(fid)) {
retval = PTR_ERR(fid);
mutex_unlock(&v9inode->v_mutex);
return retval;
}
v9inode->writeback_fid = (void *) fid;
}
mutex_unlock(&v9inode->v_mutex);
retval = generic_file_mmap(filp, vma);
if (!retval)
vma->vm_ops = &v9fs_mmap_file_vm_ops;
return retval;
}
static int
v9fs_vm_page_mkwrite(struct vm_area_struct *vma, struct vm_fault *vmf)
{
@ -658,6 +698,22 @@ v9fs_cached_file_read(struct file *filp, char __user *data, size_t count,
return do_sync_read(filp, data, count, offset);
}
/**
* v9fs_mmap_file_read - read from a file
* @filp: file pointer to read
* @udata: user data buffer to read data into
* @count: size of buffer
* @offset: offset at which to read data
*
*/
static ssize_t
v9fs_mmap_file_read(struct file *filp, char __user *data, size_t count,
loff_t *offset)
{
/* TODO: Check if there are dirty pages */
return v9fs_file_read(filp, data, count, offset);
}
static ssize_t
v9fs_direct_write(struct file *filp, const char __user * data,
size_t count, loff_t *offsetp)
@ -728,12 +784,65 @@ v9fs_cached_file_write(struct file *filp, const char __user * data,
return do_sync_write(filp, data, count, offset);
}
/**
* v9fs_mmap_file_write - write to a file
* @filp: file pointer to write
* @data: data buffer to write data from
* @count: size of buffer
* @offset: offset at which to write data
*
*/
static ssize_t
v9fs_mmap_file_write(struct file *filp, const char __user *data,
size_t count, loff_t *offset)
{
/*
* TODO: invalidate mmaps on filp's inode between
* offset and offset+count
*/
return v9fs_file_write(filp, data, count, offset);
}
static void v9fs_mmap_vm_close(struct vm_area_struct *vma)
{
struct inode *inode;
struct writeback_control wbc = {
.nr_to_write = LONG_MAX,
.sync_mode = WB_SYNC_ALL,
.range_start = vma->vm_pgoff * PAGE_SIZE,
/* absolute end, byte at end included */
.range_end = vma->vm_pgoff * PAGE_SIZE +
(vma->vm_end - vma->vm_start - 1),
};
p9_debug(P9_DEBUG_VFS, "9p VMA close, %p, flushing", vma);
inode = file_inode(vma->vm_file);
if (!mapping_cap_writeback_dirty(inode->i_mapping))
wbc.nr_to_write = 0;
might_sleep();
sync_inode(inode, &wbc);
}
static const struct vm_operations_struct v9fs_file_vm_ops = {
.fault = filemap_fault,
.page_mkwrite = v9fs_vm_page_mkwrite,
.remap_pages = generic_file_remap_pages,
};
static const struct vm_operations_struct v9fs_mmap_file_vm_ops = {
.close = v9fs_mmap_vm_close,
.fault = filemap_fault,
.page_mkwrite = v9fs_vm_page_mkwrite,
.remap_pages = generic_file_remap_pages,
};
const struct file_operations v9fs_cached_file_operations = {
.llseek = generic_file_llseek,
@ -784,3 +893,26 @@ const struct file_operations v9fs_file_operations_dotl = {
.mmap = generic_file_readonly_mmap,
.fsync = v9fs_file_fsync_dotl,
};
const struct file_operations v9fs_mmap_file_operations = {
.llseek = generic_file_llseek,
.read = v9fs_mmap_file_read,
.write = v9fs_mmap_file_write,
.open = v9fs_file_open,
.release = v9fs_dir_release,
.lock = v9fs_file_lock,
.mmap = v9fs_mmap_file_mmap,
.fsync = v9fs_file_fsync,
};
const struct file_operations v9fs_mmap_file_operations_dotl = {
.llseek = generic_file_llseek,
.read = v9fs_mmap_file_read,
.write = v9fs_mmap_file_write,
.open = v9fs_file_open,
.release = v9fs_dir_release,
.lock = v9fs_file_lock_dotl,
.flock = v9fs_file_flock_dotl,
.mmap = v9fs_mmap_file_mmap,
.fsync = v9fs_file_fsync_dotl,
};

22
fs/9p/vfs_inode.c
View File

@ -299,15 +299,22 @@ int v9fs_init_inode(struct v9fs_session_info *v9ses,
case S_IFREG:
if (v9fs_proto_dotl(v9ses)) {
inode->i_op = &v9fs_file_inode_operations_dotl;
if (v9ses->cache)
if (v9ses->cache == CACHE_LOOSE ||
v9ses->cache == CACHE_FSCACHE)
inode->i_fop =
&v9fs_cached_file_operations_dotl;
else if (v9ses->cache == CACHE_MMAP)
inode->i_fop = &v9fs_mmap_file_operations_dotl;
else
inode->i_fop = &v9fs_file_operations_dotl;
} else {
inode->i_op = &v9fs_file_inode_operations;
if (v9ses->cache)
inode->i_fop = &v9fs_cached_file_operations;
if (v9ses->cache == CACHE_LOOSE ||
v9ses->cache == CACHE_FSCACHE)
inode->i_fop =
&v9fs_cached_file_operations;
else if (v9ses->cache == CACHE_MMAP)
inode->i_fop = &v9fs_mmap_file_operations;
else
inode->i_fop = &v9fs_file_operations;
}
@ -810,7 +817,7 @@ struct dentry *v9fs_vfs_lookup(struct inode *dir, struct dentry *dentry,
* unlink. For cached mode create calls request for new
* inode. But with cache disabled, lookup should do this.
*/
if (v9ses->cache)
if (v9ses->cache == CACHE_LOOSE || v9ses->cache == CACHE_FSCACHE)
inode = v9fs_get_inode_from_fid(v9ses, fid, dir->i_sb);
else
inode = v9fs_get_new_inode_from_fid(v9ses, fid, dir->i_sb);
@ -876,7 +883,8 @@ v9fs_vfs_atomic_open(struct inode *dir, struct dentry *dentry,
v9fs_invalidate_inode_attr(dir);
v9inode = V9FS_I(dentry->d_inode);
mutex_lock(&v9inode->v_mutex);
if (v9ses->cache && !v9inode->writeback_fid &&
if ((v9ses->cache == CACHE_LOOSE || v9ses->cache == CACHE_FSCACHE) &&
!v9inode->writeback_fid &&
((flags & O_ACCMODE) != O_RDONLY)) {
/*
* clone a fid and add it to writeback_fid
@ -899,7 +907,7 @@ v9fs_vfs_atomic_open(struct inode *dir, struct dentry *dentry,
goto error;
file->private_data = fid;
if (v9ses->cache)
if (v9ses->cache == CACHE_LOOSE || v9ses->cache == CACHE_FSCACHE)
v9fs_cache_inode_set_cookie(dentry->d_inode, file);
*opened |= FILE_CREATED;
@ -1477,7 +1485,7 @@ int v9fs_refresh_inode(struct p9_fid *fid, struct inode *inode)
*/
i_size = inode->i_size;
v9fs_stat2inode(st, inode, inode->i_sb);
if (v9ses->cache)
if (v9ses->cache == CACHE_LOOSE || v9ses->cache == CACHE_FSCACHE)
inode->i_size = i_size;
spin_unlock(&inode->i_lock);
out:

9
fs/9p/vfs_inode_dotl.c
View File

@ -330,7 +330,8 @@ v9fs_vfs_atomic_open_dotl(struct inode *dir, struct dentry *dentry,
v9inode = V9FS_I(inode);
mutex_lock(&v9inode->v_mutex);
if (v9ses->cache && !v9inode->writeback_fid &&
if ((v9ses->cache == CACHE_LOOSE || v9ses->cache == CACHE_FSCACHE) &&
!v9inode->writeback_fid &&
((flags & O_ACCMODE) != O_RDONLY)) {
/*
* clone a fid and add it to writeback_fid
@ -353,7 +354,7 @@ v9fs_vfs_atomic_open_dotl(struct inode *dir, struct dentry *dentry,
if (err)
goto err_clunk_old_fid;
file->private_data = ofid;
if (v9ses->cache)
if (v9ses->cache == CACHE_LOOSE || v9ses->cache == CACHE_FSCACHE)
v9fs_cache_inode_set_cookie(inode, file);
*opened |= FILE_CREATED;
out:
@ -710,7 +711,7 @@ v9fs_vfs_symlink_dotl(struct inode *dir, struct dentry *dentry,
}
v9fs_invalidate_inode_attr(dir);
if (v9ses->cache) {
if (v9ses->cache == CACHE_LOOSE || v9ses->cache == CACHE_FSCACHE) {
/* Now walk from the parent so we can get an unopened fid. */
fid = p9_client_walk(dfid, 1, &name, 1);
if (IS_ERR(fid)) {
@ -965,7 +966,7 @@ int v9fs_refresh_inode_dotl(struct p9_fid *fid, struct inode *inode)
*/
i_size = inode->i_size;
v9fs_stat2inode_dotl(st, inode);
if (v9ses->cache)
if (v9ses->cache == CACHE_LOOSE || v9ses->cache == CACHE_FSCACHE)
inode->i_size = i_size;
spin_unlock(&inode->i_lock);
out:

8
fs/9p/vfs_super.c
View File

@ -144,7 +144,7 @@ static struct dentry *v9fs_mount(struct file_system_type *fs_type, int flags,
}
v9fs_fill_super(sb, v9ses, flags, data);
if (v9ses->cache)
if (v9ses->cache == CACHE_LOOSE || v9ses->cache == CACHE_FSCACHE)
sb->s_d_op = &v9fs_cached_dentry_operations;
else
sb->s_d_op = &v9fs_dentry_operations;
@ -282,7 +282,7 @@ static int v9fs_drop_inode(struct inode *inode)
{
struct v9fs_session_info *v9ses;
v9ses = v9fs_inode2v9ses(inode);
if (v9ses->cache)
if (v9ses->cache == CACHE_LOOSE || v9ses->cache == CACHE_FSCACHE)
return generic_drop_inode(inode);
/*
* in case of non cached mode always drop the
@ -325,10 +325,12 @@ static int v9fs_write_inode_dotl(struct inode *inode,
* send an fsync request to server irrespective of
* wbc->sync_mode.
*/
p9_debug(P9_DEBUG_VFS, "%s: inode %p\n", __func__, inode);
v9inode = V9FS_I(inode);
p9_debug(P9_DEBUG_VFS, "%s: inode %p, writeback_fid %p\n",
__func__, inode, v9inode->writeback_fid);
if (!v9inode->writeback_fid)
return 0;
ret = p9_client_fsync(v9inode->writeback_fid, 0);
if (ret < 0) {
__mark_inode_dirty(inode, I_DIRTY_DATASYNC);