diff options
| -rw-r--r-- | fs/namei.c | 51 |
1 files changed, 29 insertions, 22 deletions
diff --git a/fs/namei.c b/fs/namei.c index e133bf3bbb0..35291ac6f42 100644 --- a/fs/namei.c +++ b/fs/namei.c @@ -2395,7 +2395,7 @@ static int may_o_create(struct path *dir, struct dentry *dentry, umode_t mode) static int atomic_open(struct nameidata *nd, struct dentry *dentry, struct path *path, struct file *file, const struct open_flags *op, - bool *want_write, bool need_lookup, + bool got_write, bool need_lookup, int *opened) { struct inode *dir = nd->path.dentry->d_inode; @@ -2432,12 +2432,9 @@ static int atomic_open(struct nameidata *nd, struct dentry *dentry, * Another problem is returing the "right" error value (e.g. for an * O_EXCL open we want to return EEXIST not EROFS). */ - if ((open_flag & (O_CREAT | O_TRUNC)) || - (open_flag & O_ACCMODE) != O_RDONLY) { - error = mnt_want_write(nd->path.mnt); - if (!error) { - *want_write = true; - } else if (!(open_flag & O_CREAT)) { + if (((open_flag & (O_CREAT | O_TRUNC)) || + (open_flag & O_ACCMODE) != O_RDONLY) && unlikely(!got_write)) { + if (!(open_flag & O_CREAT)) { /* * No O_CREATE -> atomicity not a requirement -> fall * back to lookup + open @@ -2445,11 +2442,11 @@ static int atomic_open(struct nameidata *nd, struct dentry *dentry, goto no_open; } else if (open_flag & (O_EXCL | O_TRUNC)) { /* Fall back and fail with the right error */ - create_error = error; + create_error = -EROFS; goto no_open; } else { /* No side effects, safe to clear O_CREAT */ - create_error = error; + create_error = -EROFS; open_flag &= ~O_CREAT; } } @@ -2556,7 +2553,7 @@ looked_up: static int lookup_open(struct nameidata *nd, struct path *path, struct file *file, const struct open_flags *op, - bool *want_write, int *opened) + bool got_write, int *opened) { struct dentry *dir = nd->path.dentry; struct inode *dir_inode = dir->d_inode; @@ -2574,7 +2571,7 @@ static int lookup_open(struct nameidata *nd, struct path *path, goto out_no_open; if ((nd->flags & LOOKUP_OPEN) && dir_inode->i_op->atomic_open) { - return atomic_open(nd, dentry, path, file, op, want_write, + return atomic_open(nd, dentry, path, file, op, got_write, need_lookup, opened); } @@ -2598,10 +2595,10 @@ static int lookup_open(struct nameidata *nd, struct path *path, * a permanent write count is taken through * the 'struct file' in finish_open(). */ - error = mnt_want_write(nd->path.mnt); - if (error) + if (!got_write) { + error = -EROFS; goto out_dput; - *want_write = true; + } *opened |= FILE_CREATED; error = security_path_mknod(&nd->path, dentry, mode, 0); if (error) @@ -2631,7 +2628,7 @@ static int do_last(struct nameidata *nd, struct path *path, struct dentry *dir = nd->path.dentry; int open_flag = op->open_flag; bool will_truncate = (open_flag & O_TRUNC) != 0; - bool want_write = false; + bool got_write = false; int acc_mode = op->acc_mode; struct inode *inode; bool symlink_ok = false; @@ -2700,8 +2697,18 @@ static int do_last(struct nameidata *nd, struct path *path, } retry_lookup: + if (op->open_flag & (O_CREAT | O_TRUNC | O_WRONLY | O_RDWR)) { + error = mnt_want_write(nd->path.mnt); + if (!error) + got_write = true; + /* + * do _not_ fail yet - we might not need that or fail with + * a different error; let lookup_open() decide; we'll be + * dropping this one anyway. + */ + } mutex_lock(&dir->d_inode->i_mutex); - error = lookup_open(nd, path, file, op, &want_write, opened); + error = lookup_open(nd, path, file, op, got_write, opened); mutex_unlock(&dir->d_inode->i_mutex); if (error <= 0) { @@ -2736,9 +2743,9 @@ retry_lookup: * possible mount and symlink following (this might be optimized away if * necessary...) */ - if (want_write) { + if (got_write) { mnt_drop_write(nd->path.mnt); - want_write = false; + got_write = false; } error = -EEXIST; @@ -2803,7 +2810,7 @@ finish_open: error = mnt_want_write(nd->path.mnt); if (error) goto out; - want_write = true; + got_write = true; } finish_open_created: error = may_open(&nd->path, acc_mode, open_flag); @@ -2830,7 +2837,7 @@ opened: goto exit_fput; } out: - if (want_write) + if (got_write) mnt_drop_write(nd->path.mnt); path_put(&save_parent); terminate_walk(nd); @@ -2854,9 +2861,9 @@ stale_open: nd->inode = dir->d_inode; save_parent.mnt = NULL; save_parent.dentry = NULL; - if (want_write) { + if (got_write) { mnt_drop_write(nd->path.mnt); - want_write = false; + got_write = false; } retried = true; goto retry_lookup; |