This commit introduces the ability to open a character /dev/dax device instead of a block /dev/pmem device. This rests on the dev_dax_iomap patches earlier in this series. Signed-off-by: John Groves <john@xxxxxxxxxx> --- fs/famfs/famfs_inode.c | 97 +++++++++++++++++++++++++++++++++++++----- 1 file changed, 87 insertions(+), 10 deletions(-) diff --git a/fs/famfs/famfs_inode.c b/fs/famfs/famfs_inode.c index 0d659820e8ff..7d65ac497147 100644 --- a/fs/famfs/famfs_inode.c +++ b/fs/famfs/famfs_inode.c @@ -215,6 +215,93 @@ static const struct super_operations famfs_ops = { .show_options = famfs_show_options, }; +/*****************************************************************************/ + +#if defined(CONFIG_DEV_DAX_IOMAP) + +/* + * famfs dax_operations (for char dax) + */ +static int +famfs_dax_notify_failure(struct dax_device *dax_dev, u64 offset, + u64 len, int mf_flags) +{ + pr_err("%s: offset %lld len %llu flags %x\n", __func__, + offset, len, mf_flags); + return -EOPNOTSUPP; +} + +static const struct dax_holder_operations famfs_dax_holder_ops = { + .notify_failure = famfs_dax_notify_failure, +}; + +/*****************************************************************************/ + +/** + * famfs_open_char_device() + * + * Open a /dev/dax device. This only works in kernels with the dev_dax_iomap patch + */ +static int +famfs_open_char_device( + struct super_block *sb, + struct fs_context *fc) +{ + struct famfs_fs_info *fsi = sb->s_fs_info; + struct dax_device *dax_devp; + struct inode *daxdev_inode; + + int rc = 0; + + pr_notice("%s: Opening character dax device %s\n", __func__, fc->source); + + fsi->dax_filp = filp_open(fc->source, O_RDWR, 0); + if (IS_ERR(fsi->dax_filp)) { + pr_err("%s: failed to open dax device %s\n", + __func__, fc->source); + fsi->dax_filp = NULL; + return PTR_ERR(fsi->dax_filp); + } + + daxdev_inode = file_inode(fsi->dax_filp); + dax_devp = inode_dax(daxdev_inode); + if (IS_ERR(dax_devp)) { + pr_err("%s: unable to get daxdev from inode for %s\n", + __func__, fc->source); + rc = -ENODEV; + goto char_err; + } + + rc = fs_dax_get(dax_devp, fsi, &famfs_dax_holder_ops); + if (rc) { + pr_info("%s: err attaching famfs_dax_holder_ops\n", __func__); + goto char_err; + } + + fsi->bdev_handle = NULL; + fsi->dax_devp = dax_devp; + + return 0; + +char_err: + filp_close(fsi->dax_filp, NULL); + return rc; +} + +#else /* CONFIG_DEV_DAX_IOMAP */ +static int +famfs_open_char_device( + struct super_block *sb, + struct fs_context *fc) +{ + pr_err("%s: Root device is %s, but your kernel does not support famfs on /dev/dax\n", + __func__, fc->source); + return -ENODEV; +} + + +#endif /* CONFIG_DEV_DAX_IOMAP */ + /*************************************************************************************** * dax_holder_operations for block dax */ @@ -236,16 +323,6 @@ const struct dax_holder_operations famfs_blk_dax_holder_ops = { .notify_failure = famfs_blk_dax_notify_failure, }; -static int -famfs_open_char_device( - struct super_block *sb, - struct fs_context *fc) -{ - pr_err("%s: Root device is %s, but your kernel does not support famfs on /dev/dax\n", - __func__, fc->source); - return -ENODEV; -} - /** * famfs_open_device() * -- 2.43.0