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[PATCH] v9fs: fix atomic create open
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In order to assure atomic create+open v9fs stores the open fid produced by
v9fs_vfs_create in the dentry, from where v9fs_file_open retrieves it and
associates it with the open file.

This patch modifies v9fs to use nameidata.intent.open values to do the atomic
create+open.

Signed-off-by: Latchesar Ionkov <lucho@ionkov.net>
Signed-off-by: Eric Van Hensbergen <ericvh@gmail.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
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Latchesar Ionkov authored and Linus Torvalds committed Mar 2, 2006
1 parent 77a3313 commit 6a3124a
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Showing 6 changed files with 379 additions and 296 deletions.
73 changes: 17 additions & 56 deletions fs/9p/fid.c
View file
Original file line number Diff line number Diff line change
Expand Up @@ -40,7 +40,7 @@
*
*/

static int v9fs_fid_insert(struct v9fs_fid *fid, struct dentry *dentry)
int v9fs_fid_insert(struct v9fs_fid *fid, struct dentry *dentry)
{
struct list_head *fid_list = (struct list_head *)dentry->d_fsdata;
dprintk(DEBUG_9P, "fid %d (%p) dentry %s (%p)\n", fid->fid, fid,
Expand Down Expand Up @@ -68,14 +68,11 @@ static int v9fs_fid_insert(struct v9fs_fid *fid, struct dentry *dentry)
*
*/

struct v9fs_fid *v9fs_fid_create(struct dentry *dentry,
struct v9fs_session_info *v9ses, int fid, int create)
struct v9fs_fid *v9fs_fid_create(struct v9fs_session_info *v9ses, int fid)
{
struct v9fs_fid *new;

dprintk(DEBUG_9P, "fid create dentry %p, fid %d, create %d\n",
dentry, fid, create);

dprintk(DEBUG_9P, "fid create fid %d\n", fid);
new = kmalloc(sizeof(struct v9fs_fid), GFP_KERNEL);
if (new == NULL) {
dprintk(DEBUG_ERROR, "Out of Memory\n");
Expand All @@ -85,19 +82,13 @@ struct v9fs_fid *v9fs_fid_create(struct dentry *dentry,
new->fid = fid;
new->v9ses = v9ses;
new->fidopen = 0;
new->fidcreate = create;
new->fidclunked = 0;
new->iounit = 0;
new->rdir_pos = 0;
new->rdir_fcall = NULL;
INIT_LIST_HEAD(&new->list);

if (v9fs_fid_insert(new, dentry) == 0)
return new;
else {
dprintk(DEBUG_ERROR, "Problems inserting to dentry\n");
kfree(new);
return NULL;
}
}

/**
Expand All @@ -119,7 +110,7 @@ void v9fs_fid_destroy(struct v9fs_fid *fid)
static struct v9fs_fid *v9fs_fid_walk_up(struct dentry *dentry)
{
int fidnum, cfidnum, err;
struct v9fs_fid *cfid;
struct v9fs_fid *cfid, *fid;
struct dentry *cde;
struct v9fs_session_info *v9ses;

Expand Down Expand Up @@ -158,7 +149,16 @@ static struct v9fs_fid *v9fs_fid_walk_up(struct dentry *dentry)
cde = cde->d_parent;
}

return v9fs_fid_create(dentry, v9ses, fidnum, 0);
fid = v9fs_fid_create(v9ses, fidnum);
if (fid) {
err = v9fs_fid_insert(fid, dentry);
if (err < 0) {
kfree(fid);
goto clunk_fid;
}
}

return fid;

clunk_fid:
v9fs_t_clunk(v9ses, fidnum);
Expand All @@ -179,29 +179,12 @@ static struct v9fs_fid *v9fs_fid_walk_up(struct dentry *dentry)
struct v9fs_fid *v9fs_fid_lookup(struct dentry *dentry)
{
struct list_head *fid_list = (struct list_head *)dentry->d_fsdata;
struct v9fs_fid *current_fid = NULL;
struct v9fs_fid *temp = NULL;
struct v9fs_fid *return_fid = NULL;

dprintk(DEBUG_9P, " dentry: %s (%p)\n", dentry->d_iname, dentry);

if (fid_list) {
list_for_each_entry_safe(current_fid, temp, fid_list, list) {
if (!current_fid->fidcreate) {
return_fid = current_fid;
break;
}
}

if (!return_fid)
return_fid = current_fid;
}

/* we are at the root but didn't match */
if ((!return_fid) && (dentry->d_parent == dentry)) {
/* TODO: clone attach with new uid */
return_fid = current_fid;
}
if (fid_list)
return_fid = list_entry(fid_list->next, struct v9fs_fid, list);

if (!return_fid) {
struct dentry *par = current->fs->pwd->d_parent;
Expand All @@ -228,25 +211,3 @@ struct v9fs_fid *v9fs_fid_lookup(struct dentry *dentry)

return return_fid;
}

struct v9fs_fid *v9fs_fid_get_created(struct dentry *dentry)
{
struct list_head *fid_list;
struct v9fs_fid *fid, *ftmp, *ret;

dprintk(DEBUG_9P, " dentry: %s (%p)\n", dentry->d_iname, dentry);
fid_list = (struct list_head *)dentry->d_fsdata;
ret = NULL;
if (fid_list) {
list_for_each_entry_safe(fid, ftmp, fid_list, list) {
if (fid->fidcreate && fid->pid == current->pid) {
list_del(&fid->list);
ret = fid;
break;
}
}
}

dprintk(DEBUG_9P, "return %p\n", ret);
return ret;
}
5 changes: 2 additions & 3 deletions fs/9p/fid.h
View file
Original file line number Diff line number Diff line change
Expand Up @@ -33,7 +33,6 @@ struct v9fs_fid {

u32 fid;
unsigned char fidopen; /* set when fid is opened */
unsigned char fidcreate; /* set when fid was just created */
unsigned char fidclunked; /* set when fid has already been clunked */

struct v9fs_qid qid;
Expand All @@ -56,5 +55,5 @@ struct v9fs_fid {
struct v9fs_fid *v9fs_fid_lookup(struct dentry *dentry);
struct v9fs_fid *v9fs_fid_get_created(struct dentry *);
void v9fs_fid_destroy(struct v9fs_fid *fid);
struct v9fs_fid *v9fs_fid_create(struct dentry *,
struct v9fs_session_info *v9ses, int fid, int create);
struct v9fs_fid *v9fs_fid_create(struct v9fs_session_info *, int fid);
int v9fs_fid_insert(struct v9fs_fid *fid, struct dentry *dentry);
1 change: 1 addition & 0 deletions fs/9p/v9fs_vfs.h
View file
Original file line number Diff line number Diff line change
Expand Up @@ -51,3 +51,4 @@ int v9fs_dir_release(struct inode *inode, struct file *filp);
int v9fs_file_open(struct inode *inode, struct file *file);
void v9fs_inode2stat(struct inode *inode, struct v9fs_stat *stat);
void v9fs_dentry_release(struct dentry *);
int v9fs_uflags2omode(int uflags);
106 changes: 40 additions & 66 deletions fs/9p/vfs_file.c
View file
Original file line number Diff line number Diff line change
Expand Up @@ -53,94 +53,70 @@
int v9fs_file_open(struct inode *inode, struct file *file)
{
struct v9fs_session_info *v9ses = v9fs_inode2v9ses(inode);
struct v9fs_fid *v9fid, *fid;
struct v9fs_fid *vfid;
struct v9fs_fcall *fcall = NULL;
int open_mode = 0;
unsigned int iounit = 0;
int newfid = -1;
long result = -1;
int omode;
int fid = V9FS_NOFID;
int err;

dprintk(DEBUG_VFS, "inode: %p file: %p \n", inode, file);

v9fid = v9fs_fid_get_created(file->f_dentry);
if (!v9fid)
v9fid = v9fs_fid_lookup(file->f_dentry);

if (!v9fid) {
vfid = v9fs_fid_lookup(file->f_dentry);
if (!vfid) {
dprintk(DEBUG_ERROR, "Couldn't resolve fid from dentry\n");
return -EBADF;
}

if (!v9fid->fidcreate) {
fid = kmalloc(sizeof(struct v9fs_fid), GFP_KERNEL);
if (fid == NULL) {
dprintk(DEBUG_ERROR, "Out of Memory\n");
return -ENOMEM;
}

fid->fidopen = 0;
fid->fidcreate = 0;
fid->fidclunked = 0;
fid->iounit = 0;
fid->v9ses = v9ses;

newfid = v9fs_get_idpool(&v9ses->fidpool);
if (newfid < 0) {
fid = v9fs_get_idpool(&v9ses->fidpool);
if (fid < 0) {
eprintk(KERN_WARNING, "newfid fails!\n");
return -ENOSPC;
}

result =
v9fs_t_walk(v9ses, v9fid->fid, newfid, NULL, NULL);

if (result < 0) {
v9fs_put_idpool(newfid, &v9ses->fidpool);
err = v9fs_t_walk(v9ses, vfid->fid, fid, NULL, NULL);
if (err < 0) {
dprintk(DEBUG_ERROR, "rewalk didn't work\n");
return -EBADF;
goto put_fid;
}

vfid = kmalloc(sizeof(struct v9fs_fid), GFP_KERNEL);
if (vfid == NULL) {
dprintk(DEBUG_ERROR, "out of memory\n");
goto clunk_fid;
}

fid->fid = newfid;
v9fid = fid;
/* TODO: do special things for O_EXCL, O_NOFOLLOW, O_SYNC */
/* translate open mode appropriately */
open_mode = file->f_flags & 0x3;
omode = v9fs_uflags2omode(file->f_flags);
err = v9fs_t_open(v9ses, fid, omode, &fcall);
if (err < 0) {
PRINT_FCALL_ERROR("open failed", fcall);
goto destroy_vfid;
}

if (file->f_flags & O_EXCL)
open_mode |= V9FS_OEXCL;
file->private_data = vfid;
vfid->fid = fid;
vfid->fidopen = 1;
vfid->fidclunked = 0;
vfid->iounit = fcall->params.ropen.iounit;
vfid->rdir_pos = 0;
vfid->rdir_fcall = NULL;
vfid->filp = file;
kfree(fcall);

if (v9ses->extended) {
if (file->f_flags & O_TRUNC)
open_mode |= V9FS_OTRUNC;
return 0;

if (file->f_flags & O_APPEND)
open_mode |= V9FS_OAPPEND;
}
destroy_vfid:
v9fs_fid_destroy(vfid);

result = v9fs_t_open(v9ses, newfid, open_mode, &fcall);
if (result < 0) {
PRINT_FCALL_ERROR("open failed", fcall);
kfree(fcall);
return result;
}
clunk_fid:
v9fs_t_clunk(v9ses, fid);

iounit = fcall->params.ropen.iounit;
put_fid:
v9fs_put_idpool(fid, &v9ses->fidpool);
kfree(fcall);
} else {
/* create case */
newfid = v9fid->fid;
iounit = v9fid->iounit;
v9fid->fidcreate = 0;
}

file->private_data = v9fid;

v9fid->rdir_pos = 0;
v9fid->rdir_fcall = NULL;
v9fid->fidopen = 1;
v9fid->filp = file;
v9fid->iounit = iounit;

return 0;
return err;
}

/**
Expand Down Expand Up @@ -289,9 +265,7 @@ v9fs_file_write(struct file *filp, const char __user * data,
total += result;
} while (count);

if(inode->i_mapping->nrpages)
invalidate_inode_pages2(inode->i_mapping);

return total;
}

Expand Down
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