[PATCH] v9fs: fix atomic create open

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>

1 files changed, 312 insertions, 166 deletions

diff --git a/fs/9p/vfs_inode.c b/fs/9p/vfs_inode.c
index 63e5b0398e8b..dce729d42869 100644
--- a/fs/9p/vfs_inode.c
+++ b/fs/9p/vfs_inode.c
@@ -125,6 +125,38 @@ static int p9mode2unixmode(struct v9fs_session_info *v9ses, int mode)
         return res;
 }
 
+int v9fs_uflags2omode(int uflags)
+{
+        int ret;
+
+        ret = 0;
+        switch (uflags&3) {
+        default:
+        case O_RDONLY:
+                ret = V9FS_OREAD;
+                break;
+
+        case O_WRONLY:
+                ret = V9FS_OWRITE;
+                break;
+
+        case O_RDWR:
+                ret = V9FS_ORDWR;
+                break;
+        }
+
+        if (uflags & O_EXCL)
+                ret |= V9FS_OEXCL;
+
+        if (uflags & O_TRUNC)
+                ret |= V9FS_OTRUNC;
+
+        if (uflags & O_APPEND)
+                ret |= V9FS_OAPPEND;
+
+        return ret;
+}
+
 /**
  * v9fs_blank_wstat - helper function to setup a 9P stat structure
  * @v9ses: 9P session info (for determining extended mode)
@@ -163,7 +195,7 @@ v9fs_blank_wstat(struct v9fs_wstat *wstat)
 
 struct inode *v9fs_get_inode(struct super_block *sb, int mode)
 {
-        struct inode *inode = NULL;
+        struct inode *inode;
         struct v9fs_session_info *v9ses = sb->s_fs_info;
 
         dprintk(DEBUG_VFS, "super block: %p mode: %o\n", sb, mode);
@@ -222,171 +254,135 @@ struct inode *v9fs_get_inode(struct super_block *sb, int mode)
         return inode;
 }
 
-/**
- * v9fs_create - helper function to create files and directories
- * @dir: directory inode file is being created in
- * @file_dentry: dentry file is being created in
- * @perm: permissions file is being created with
- * @open_mode: resulting open mode for file
- *
- */
-
 static int
-v9fs_create(struct inode *dir,
-            struct dentry *file_dentry,
-            unsigned int perm, unsigned int open_mode)
+v9fs_create(struct v9fs_session_info *v9ses, u32 pfid, char *name,
+        u32 perm, u8 mode, u32 *fidp, struct v9fs_qid *qid, u32 *iounit)
 {
-        struct v9fs_session_info *v9ses = v9fs_inode2v9ses(dir);
-        struct super_block *sb = dir->i_sb;
-        struct v9fs_fid *dirfid =
-            v9fs_fid_lookup(file_dentry->d_parent);
-        struct v9fs_fid *fid = NULL;
-        struct inode *file_inode = NULL;
-        struct v9fs_fcall *fcall = NULL;
-        struct v9fs_qid qid;
-        int dirfidnum = -1;
-        long newfid = -1;
-        int result = 0;
-        unsigned int iounit = 0;
-        int wfidno = -1;
+        u32 fid;
         int err;
+        struct v9fs_fcall *fcall;
 
-        perm = unixmode2p9mode(v9ses, perm);
-
-        dprintk(DEBUG_VFS, "dir: %p dentry: %p perm: %o mode: %o\n", dir,
-                file_dentry, perm, open_mode);
-
-        if (!dirfid)
-                return -EBADF;
-
-        dirfidnum = dirfid->fid;
-        if (dirfidnum < 0) {
-                dprintk(DEBUG_ERROR, "No fid for the directory #%lu\n",
-                        dir->i_ino);
-                return -EBADF;
-        }
-
-        if (file_dentry->d_inode) {
-                dprintk(DEBUG_ERROR,
-                        "Odd. There is an inode for dir %lu, name :%s:\n",
-                        dir->i_ino, file_dentry->d_name.name);
-                return -EEXIST;
-        }
-
-        newfid = v9fs_get_idpool(&v9ses->fidpool);
-        if (newfid < 0) {
+        fid = v9fs_get_idpool(&v9ses->fidpool);
+        if (fid < 0) {
                 eprintk(KERN_WARNING, "no free fids available\n");
-                return -ENOSPC;
+                err = -ENOSPC;
+                goto error;
         }
 
-        result = v9fs_t_walk(v9ses, dirfidnum, newfid, NULL, &fcall);
-        if (result < 0) {
+        err = v9fs_t_walk(v9ses, pfid, fid, NULL, &fcall);
+        if (err < 0) {
                 PRINT_FCALL_ERROR("clone error", fcall);
-                v9fs_put_idpool(newfid, &v9ses->fidpool);
-                newfid = -1;
-                goto CleanUpFid;
+                goto error;
         }
-
         kfree(fcall);
-        fcall = NULL;
 
-        result = v9fs_t_create(v9ses, newfid, (char *)file_dentry->d_name.name,
-                               perm, open_mode, &fcall);
-        if (result < 0) {
+        err = v9fs_t_create(v9ses, fid, name, perm, mode, &fcall);
+        if (err < 0) {
                 PRINT_FCALL_ERROR("create fails", fcall);
-                goto CleanUpFid;
+                goto error;
         }
 
-        iounit = fcall->params.rcreate.iounit;
-        qid = fcall->params.rcreate.qid;
+        if (iounit)
+                *iounit = fcall->params.rcreate.iounit;
+
+        if (qid)
+                *qid = fcall->params.rcreate.qid;
+
+        if (fidp)
+                *fidp = fid;
+
         kfree(fcall);
-        fcall = NULL;
+        return 0;
 
-        if (!(perm&V9FS_DMDIR)) {
-                fid = v9fs_fid_create(file_dentry, v9ses, newfid, 1);
-                dprintk(DEBUG_VFS, "fid %p %d\n", fid, fid->fidcreate);
-                if (!fid) {
-                        result = -ENOMEM;
-                        goto CleanUpFid;
-                }
+error:
+        if (fid >= 0)
+                v9fs_put_idpool(fid, &v9ses->fidpool);
 
-                fid->qid = qid;
-                fid->iounit = iounit;
-        } else {
-                err = v9fs_t_clunk(v9ses, newfid);
-                newfid = -1;
-                if (err < 0)
-                        dprintk(DEBUG_ERROR, "clunk for mkdir failed: %d\n", err);
-        }
+        kfree(fcall);
+        return err;
+}
+
+static struct v9fs_fid*
+v9fs_clone_walk(struct v9fs_session_info *v9ses, u32 fid, struct dentry *dentry)
+{
+        int err;
+        u32 nfid;
+        struct v9fs_fid *ret;
+        struct v9fs_fcall *fcall;
 
-        /* walk to the newly created file and put the fid in the dentry */
-        wfidno = v9fs_get_idpool(&v9ses->fidpool);
-        if (wfidno < 0) {
+        nfid = v9fs_get_idpool(&v9ses->fidpool);
+        if (nfid < 0) {
                 eprintk(KERN_WARNING, "no free fids available\n");
-                return -ENOSPC;
+                err = -ENOSPC;
+                goto error;
         }
 
-        result = v9fs_t_walk(v9ses, dirfidnum, wfidno,
-                (char *) file_dentry->d_name.name, &fcall);
-        if (result < 0) {
-                PRINT_FCALL_ERROR("clone error", fcall);
-                v9fs_put_idpool(wfidno, &v9ses->fidpool);
-                wfidno = -1;
-                goto CleanUpFid;
+        err = v9fs_t_walk(v9ses, fid, nfid, (char *) dentry->d_name.name,
+                &fcall);
+
+        if (err < 0) {
+                PRINT_FCALL_ERROR("walk error", fcall);
+                v9fs_put_idpool(nfid, &v9ses->fidpool);
+                goto error;
         }
+
         kfree(fcall);
         fcall = NULL;
+        ret = v9fs_fid_create(v9ses, nfid);
+        if (!ret) {
+                err = -ENOMEM;
+                goto clunk_fid;
+        }
 
-        if (!v9fs_fid_create(file_dentry, v9ses, wfidno, 0)) {
-                v9fs_put_idpool(wfidno, &v9ses->fidpool);
-
-                goto CleanUpFid;
+        err = v9fs_fid_insert(ret, dentry);
+        if (err < 0) {
+                v9fs_fid_destroy(ret);
+                goto clunk_fid;
         }
 
-        if ((perm & V9FS_DMSYMLINK) || (perm & V9FS_DMLINK) ||
-            (perm & V9FS_DMNAMEDPIPE) || (perm & V9FS_DMSOCKET) ||
-            (perm & V9FS_DMDEVICE))
-                return 0;
+        return ret;
 
-        result = v9fs_t_stat(v9ses, wfidno, &fcall);
-        if (result < 0) {
-                PRINT_FCALL_ERROR("stat error", fcall);
-                goto CleanUpFid;
-        }
+clunk_fid:
+        v9fs_t_clunk(v9ses, nfid);
+
+error:
+        kfree(fcall);
+        return ERR_PTR(err);
+}
 
+struct inode *
+v9fs_inode_from_fid(struct v9fs_session_info *v9ses, u32 fid,
+        struct super_block *sb)
+{
+        int err, umode;
+        struct inode *ret;
+        struct v9fs_fcall *fcall;
 
-        file_inode = v9fs_get_inode(sb,
-                p9mode2unixmode(v9ses, fcall->params.rstat.stat.mode));
+        ret = NULL;
+        err = v9fs_t_stat(v9ses, fid, &fcall);
+        if (err) {
+                PRINT_FCALL_ERROR("stat error", fcall);
+                goto error;
+        }
 
-        if ((!file_inode) || IS_ERR(file_inode)) {
-                dprintk(DEBUG_ERROR, "create inode failed\n");
-                result = -EBADF;
-                goto CleanUpFid;
+        umode = p9mode2unixmode(v9ses, fcall->params.rstat.stat.mode);
+        ret = v9fs_get_inode(sb, umode);
+        if (IS_ERR(ret)) {
+                err = PTR_ERR(ret);
+                ret = NULL;
+                goto error;
         }
 
-        v9fs_stat2inode(&fcall->params.rstat.stat, file_inode, sb);
+        v9fs_stat2inode(&fcall->params.rstat.stat, ret, sb);
         kfree(fcall);
-        fcall = NULL;
-        file_dentry->d_op = &v9fs_dentry_operations;
-        d_instantiate(file_dentry, file_inode);
-
-        return 0;
+        return ret;
 
-      CleanUpFid:
+error:
         kfree(fcall);
-        fcall = NULL;
+        if (ret)
+                iput(ret);
 
-        if (newfid >= 0) {
-                err = v9fs_t_clunk(v9ses, newfid);
-                if (err < 0)
-                        dprintk(DEBUG_ERROR, "clunk failed: %d\n", err);
-        }
-        if (wfidno >= 0) {
-                err = v9fs_t_clunk(v9ses, wfidno);
-                if (err < 0)
-                        dprintk(DEBUG_ERROR, "clunk failed: %d\n", err);
-        }
-        return result;
+        return ERR_PTR(err);
 }
 
 /**
@@ -440,20 +436,97 @@ static int v9fs_remove(struct inode *dir, struct dentry *file, int rmdir)
         return result;
 }
 
+static int
+v9fs_open_created(struct inode *inode, struct file *file)
+{
+        return 0;
+}
+
 /**
  * v9fs_vfs_create - VFS hook to create files
  * @inode: directory inode that is being deleted
  * @dentry:  dentry that is being deleted
- * @perm: create permissions
+ * @mode: create permissions
  * @nd: path information
  *
  */
 
 static int
-v9fs_vfs_create(struct inode *inode, struct dentry *dentry, int perm,
+v9fs_vfs_create(struct inode *dir, struct dentry *dentry, int mode,
                 struct nameidata *nd)
 {
-        return v9fs_create(inode, dentry, perm, O_RDWR);
+        int err;
+        u32 fid, perm, iounit;
+        int flags;
+        struct v9fs_session_info *v9ses;
+        struct v9fs_fid *dfid, *vfid, *ffid;
+        struct inode *inode;
+        struct v9fs_qid qid;
+        struct file *filp;
+
+        inode = NULL;
+        vfid = NULL;
+        v9ses = v9fs_inode2v9ses(dir);
+        dfid = v9fs_fid_lookup(dentry->d_parent);
+        perm = unixmode2p9mode(v9ses, mode);
+
+        if (nd && nd->flags & LOOKUP_OPEN)
+                flags = nd->intent.open.flags - 1;
+        else
+                flags = O_RDWR;
+
+        err = v9fs_create(v9ses, dfid->fid, (char *) dentry->d_name.name,
+                perm, v9fs_uflags2omode(flags), &fid, &qid, &iounit);
+
+        if (err)
+                goto error;
+
+        vfid = v9fs_clone_walk(v9ses, dfid->fid, dentry);
+        if (IS_ERR(vfid)) {
+                err = PTR_ERR(vfid);
+                vfid = NULL;
+                goto error;
+        }
+
+        inode = v9fs_inode_from_fid(v9ses, vfid->fid, dir->i_sb);
+        if (IS_ERR(inode)) {
+                err = PTR_ERR(inode);
+                inode = NULL;
+                goto error;
+        }
+
+        dentry->d_op = &v9fs_dentry_operations;
+        d_instantiate(dentry, inode);
+
+        if (nd && nd->flags & LOOKUP_OPEN) {
+                ffid = v9fs_fid_create(v9ses, fid);
+                if (!ffid)
+                        return -ENOMEM;
+
+                filp = lookup_instantiate_filp(nd, dentry, v9fs_open_created);
+                if (IS_ERR(filp)) {
+                        v9fs_fid_destroy(ffid);
+                        return PTR_ERR(filp);
+                }
+
+                ffid->rdir_pos = 0;
+                ffid->rdir_fcall = NULL;
+                ffid->fidopen = 1;
+                ffid->iounit = iounit;
+                ffid->filp = filp;
+                filp->private_data = ffid;
+        }
+
+        return 0;
+
+error:
+        if (vfid)
+                v9fs_fid_destroy(vfid);
+
+        if (inode)
+                iput(inode);
+
+        return err;
 }
 
 /**
@@ -464,9 +537,57 @@ v9fs_vfs_create(struct inode *inode, struct dentry *dentry, int perm,
  *
  */
 
-static int v9fs_vfs_mkdir(struct inode *inode, struct dentry *dentry, int mode)
+static int v9fs_vfs_mkdir(struct inode *dir, struct dentry *dentry, int mode)
 {
-        return v9fs_create(inode, dentry, mode | S_IFDIR, O_RDONLY);
+        int err;
+        u32 fid, perm;
+        struct v9fs_session_info *v9ses;
+        struct v9fs_fid *dfid, *vfid;
+        struct inode *inode;
+
+        inode = NULL;
+        vfid = NULL;
+        v9ses = v9fs_inode2v9ses(dir);
+        dfid = v9fs_fid_lookup(dentry->d_parent);
+        perm = unixmode2p9mode(v9ses, mode | S_IFDIR);
+
+        err = v9fs_create(v9ses, dfid->fid, (char *) dentry->d_name.name,
+                perm, V9FS_OREAD, &fid, NULL, NULL);
+
+        if (err) {
+                dprintk(DEBUG_ERROR, "create error %d\n", err);
+                goto error;
+        }
+
+        err = v9fs_t_clunk(v9ses, fid);
+        if (err) {
+                dprintk(DEBUG_ERROR, "clunk error %d\n", err);
+                goto error;
+        }
+
+        vfid = v9fs_clone_walk(v9ses, dfid->fid, dentry);
+        if (IS_ERR(vfid)) {
+                err = PTR_ERR(vfid);
+                vfid = NULL;
+                goto error;
+        }
+
+        inode = v9fs_inode_from_fid(v9ses, vfid->fid, dir->i_sb);
+        if (IS_ERR(inode)) {
+                err = PTR_ERR(inode);
+                inode = NULL;
+                goto error;
+        }
+
+        dentry->d_op = &v9fs_dentry_operations;
+        d_instantiate(dentry, inode);
+        return 0;
+
+error:
+        if (vfid)
+                v9fs_fid_destroy(vfid);
+
+        return err;
 }
 
 /**
@@ -516,9 +637,8 @@ static struct dentry *v9fs_vfs_lookup(struct inode *dir, struct dentry *dentry,
                 return ERR_PTR(-ENOSPC);
         }
 
-        result =
-            v9fs_t_walk(v9ses, dirfidnum, newfid, (char *)dentry->d_name.name,
-                        NULL);
+        result = v9fs_t_walk(v9ses, dirfidnum, newfid,
+                (char *)dentry->d_name.name, NULL);
         if (result < 0) {
                 v9fs_put_idpool(newfid, &v9ses->fidpool);
                 if (result == -ENOENT) {
@@ -551,13 +671,17 @@ static struct dentry *v9fs_vfs_lookup(struct inode *dir, struct dentry *dentry,
 
         inode->i_ino = v9fs_qid2ino(&fcall->params.rstat.stat.qid);
 
-        fid = v9fs_fid_create(dentry, v9ses, newfid, 0);
+        fid = v9fs_fid_create(v9ses, newfid);
         if (fid == NULL) {
                 dprintk(DEBUG_ERROR, "couldn't insert\n");
                 result = -ENOMEM;
                 goto FreeFcall;
         }
 
+        result = v9fs_fid_insert(fid, dentry);
+        if (result < 0)
+                goto FreeFcall;
+
         fid->qid = fcall->params.rstat.stat.qid;
 
         dentry->d_op = &v9fs_dentry_operations;
@@ -886,8 +1010,8 @@ static int v9fs_readlink(struct dentry *dentry, char *buffer, int buflen)
         }
 
         /* copy extension buffer into buffer */
-        if (fcall->params.rstat.stat.extension.len+1 < buflen)
-                buflen = fcall->params.rstat.stat.extension.len + 1;
+        if (fcall->params.rstat.stat.extension.len < buflen)
+                buflen = fcall->params.rstat.stat.extension.len;
 
         memcpy(buffer, fcall->params.rstat.stat.extension.str, buflen - 1);
         buffer[buflen-1] = 0;
@@ -951,7 +1075,7 @@ static void *v9fs_vfs_follow_link(struct dentry *dentry, struct nameidata *nd)
         if (!link)
                 link = ERR_PTR(-ENOMEM);
         else {
-                len = v9fs_readlink(dentry, link, PATH_MAX);
+                len = v9fs_readlink(dentry, link, strlen(link));
 
                 if (len < 0) {
                         __putname(link);
@@ -983,53 +1107,75 @@ static void v9fs_vfs_put_link(struct dentry *dentry, struct nameidata *nd, void
 static int v9fs_vfs_mkspecial(struct inode *dir, struct dentry *dentry,
         int mode, const char *extension)
 {
-        int err, retval;
+        int err;
+        u32 fid, perm;
         struct v9fs_session_info *v9ses;
+        struct v9fs_fid *dfid, *vfid;
+        struct inode *inode;
         struct v9fs_fcall *fcall;
-        struct v9fs_fid *fid;
         struct v9fs_wstat wstat;
 
-        v9ses = v9fs_inode2v9ses(dir);
-        retval = -EPERM;
         fcall = NULL;
+        inode = NULL;
+        vfid = NULL;
+        v9ses = v9fs_inode2v9ses(dir);
+        dfid = v9fs_fid_lookup(dentry->d_parent);
+        perm = unixmode2p9mode(v9ses, mode);
 
         if (!v9ses->extended) {
                 dprintk(DEBUG_ERROR, "not extended\n");
-                goto free_mem;
+                return -EPERM;
         }
 
-        /* issue a create */
-        retval = v9fs_create(dir, dentry, mode, 0);
-        if (retval != 0)
-                goto free_mem;
+        err = v9fs_create(v9ses, dfid->fid, (char *) dentry->d_name.name,
+                perm, V9FS_OREAD, &fid, NULL, NULL);
 
-        fid = v9fs_fid_get_created(dentry);
-        if (!fid) {
-                dprintk(DEBUG_ERROR, "couldn't resolve fid from dentry\n");
-                goto free_mem;
+        if (err)
+                goto error;
+
+        err = v9fs_t_clunk(v9ses, fid);
+        if (err)
+                goto error;
+
+        vfid = v9fs_clone_walk(v9ses, dfid->fid, dentry);
+        if (IS_ERR(vfid)) {
+                err = PTR_ERR(vfid);
+                vfid = NULL;
+                goto error;
+        }
+
+        inode = v9fs_inode_from_fid(v9ses, vfid->fid, dir->i_sb);
+        if (IS_ERR(inode)) {
+                err = PTR_ERR(inode);
+                inode = NULL;
+                goto error;
         }
 
         /* issue a Twstat */
         v9fs_blank_wstat(&wstat);
         wstat.muid = v9ses->name;
         wstat.extension = (char *) extension;
-        retval = v9fs_t_wstat(v9ses, fid->fid, &wstat, &fcall);
-        if (retval < 0) {
-                PRINT_FCALL_ERROR("wstat error", fcall);
-                goto free_mem;
-        }
-
-        err = v9fs_t_clunk(v9ses, fid->fid);
+        err = v9fs_t_wstat(v9ses, vfid->fid, &wstat, &fcall);
         if (err < 0) {
-                dprintk(DEBUG_ERROR, "clunk failed: %d\n", err);
-                goto free_mem;
+                PRINT_FCALL_ERROR("wstat error", fcall);
+                goto error;
         }
 
-        d_drop(dentry);         /* FID - will this also clunk? */
+        kfree(fcall);
+        dentry->d_op = &v9fs_dentry_operations;
+        d_instantiate(dentry, inode);
+        return 0;
 
-free_mem:
+error:
         kfree(fcall);
-        return retval;
+        if (vfid)
+                v9fs_fid_destroy(vfid);
+
+        if (inode)
+                iput(inode);
+
+        return err;
+
 }
 
 /**