Hi, A while ago there was a discussion about supporting direct-io on tmpfs.
Here is a simple patch that does it. 1. A new fs flag FS_RAM_BASED is added and the O_DIRECT flag is ignored if this flag is set (suggestions on a better name?) 2. Specify FS_RAM_BASED for tmpfs and ramfs. 3. When EINVAL is returned only a fput is done. I changed it to go through cleanup_all. But there is still a cleanup problem: If a new file is created and then EINVAL is returned due to O_DIRECT, the file is still left on the disk. I am not exactly sure how to fix it other than adding another fs flag so we could check O_DIRECT support at a much earlier stage. Comments on how to fix it? Signed-off-by: Hua Zhong <[EMAIL PROTECTED]> diff --git a/fs/open.c b/fs/open.c index c989fb4..c03285f 100644 --- a/fs/open.c +++ b/fs/open.c @@ -708,11 +708,13 @@ static struct file *__dentry_open(struct /* NB: we're sure to have correct a_ops only after f_op->open */ if (f->f_flags & O_DIRECT) { - if (!f->f_mapping->a_ops || - ((!f->f_mapping->a_ops->direct_IO) && - (!f->f_mapping->a_ops->get_xip_page))) { - fput(f); - f = ERR_PTR(-EINVAL); + if (dentry->d_sb->s_type->fs_flags & FS_RAM_BASED) + f->f_flags &= ~O_DIRECT; + else if (!f->f_mapping->a_ops || + ((!f->f_mapping->a_ops->direct_IO) && + (!f->f_mapping->a_ops->get_xip_page))) { + error = -EINVAL; + goto cleanup_all; } } diff --git a/fs/ramfs/inode.c b/fs/ramfs/inode.c index 2faf4cd..0d4bebc 100644 --- a/fs/ramfs/inode.c +++ b/fs/ramfs/inode.c @@ -199,11 +199,13 @@ static int rootfs_get_sb(struct file_sys static struct file_system_type ramfs_fs_type = { .name = "ramfs", + .fs_flags = FS_RAM_BASED, .get_sb = ramfs_get_sb, .kill_sb = kill_litter_super, }; static struct file_system_type rootfs_fs_type = { .name = "rootfs", + .fs_flags = FS_RAM_BASED, .get_sb = rootfs_get_sb, .kill_sb = kill_litter_super, }; diff --git a/include/linux/fs.h b/include/linux/fs.h index 186da81..0d95988 100644 --- a/include/linux/fs.h +++ b/include/linux/fs.h @@ -91,6 +91,7 @@ extern int dir_notify_enable; /* public flags for file_system_type */ #define FS_REQUIRES_DEV 1 #define FS_BINARY_MOUNTDATA 2 +#define FS_RAM_BASED 8192 /* Ignore O_DIRECT */ #define FS_REVAL_DOT 16384 /* Check the paths ".", ".." for staleness */ #define FS_RENAME_DOES_D_MOVE 32768 /* FS will handle d_move() * during rename() internally. diff --git a/mm/shmem.c b/mm/shmem.c index 70da7a0..5d23e8a 100644 --- a/mm/shmem.c +++ b/mm/shmem.c @@ -2413,6 +2413,7 @@ static int shmem_get_sb(struct file_syst static struct file_system_type tmpfs_fs_type = { .owner = THIS_MODULE, .name = "tmpfs", + .fs_flags = FS_RAM_BASED, .get_sb = shmem_get_sb, .kill_sb = kill_litter_super, }; - To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to [EMAIL PROTECTED] More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/