From: Ira Weiny <ira.weiny@xxxxxxxxx> We add 'always', 'never', and 'inode' (default). '-o dax' continue to operate the same. Specifically we introduce a 2nd DAX mount flag EXT4_MOUNT_NODAX and set it and EXT4_MOUNT_DAX appropriately. We also force EXT4_MOUNT_NODAX if !CONFIG_FS_DAX. https://lore.kernel.org/lkml/20200405061945.GA94792@xxxxxxxxxxxxxxxxxxxxxxxxx/ Signed-off-by: Ira Weiny <ira.weiny@xxxxxxxxx> --- fs/ext4/ext4.h | 1 + fs/ext4/super.c | 43 +++++++++++++++++++++++++++++++++++++++---- 2 files changed, 40 insertions(+), 4 deletions(-) diff --git a/fs/ext4/ext4.h b/fs/ext4/ext4.h index 434021fcec88..aadf33d5b37d 100644 --- a/fs/ext4/ext4.h +++ b/fs/ext4/ext4.h @@ -1174,6 +1174,7 @@ struct ext4_inode_info { blocks */ #define EXT4_MOUNT2_HURD_COMPAT 0x00000004 /* Support HURD-castrated file systems */ +#define EXT4_MOUNT2_NODAX 0x00000008 /* Do not allow Direct Access */ #define EXT4_MOUNT2_EXPLICIT_JOURNAL_CHECKSUM 0x00000008 /* User explicitly specified journal checksum */ diff --git a/fs/ext4/super.c b/fs/ext4/super.c index b14863058115..0175fbfeb2ea 100644 --- a/fs/ext4/super.c +++ b/fs/ext4/super.c @@ -1510,6 +1510,7 @@ enum { Opt_jqfmt_vfsold, Opt_jqfmt_vfsv0, Opt_jqfmt_vfsv1, Opt_quota, Opt_noquota, Opt_barrier, Opt_nobarrier, Opt_err, Opt_usrquota, Opt_grpquota, Opt_prjquota, Opt_i_version, Opt_dax, + Opt_dax_str, Opt_stripe, Opt_delalloc, Opt_nodelalloc, Opt_warn_on_error, Opt_nowarn_on_error, Opt_mblk_io_submit, Opt_lazytime, Opt_nolazytime, Opt_debug_want_extra_isize, @@ -1575,6 +1576,7 @@ static const match_table_t tokens = { {Opt_barrier, "barrier"}, {Opt_nobarrier, "nobarrier"}, {Opt_i_version, "i_version"}, + {Opt_dax_str, "dax=%s"}, {Opt_dax, "dax"}, {Opt_stripe, "stripe=%u"}, {Opt_delalloc, "delalloc"}, @@ -1772,6 +1774,7 @@ static const struct mount_opts { {Opt_min_batch_time, 0, MOPT_GTE0}, {Opt_inode_readahead_blks, 0, MOPT_GTE0}, {Opt_init_itable, 0, MOPT_GTE0}, + {Opt_dax_str, 0, MOPT_STRING}, {Opt_dax, EXT4_MOUNT_DAX, MOPT_SET}, {Opt_stripe, 0, MOPT_GTE0}, {Opt_resuid, 0, MOPT_GTE0}, @@ -2081,13 +2084,32 @@ static int handle_mount_opt(struct super_block *sb, char *opt, int token, } sbi->s_jquota_fmt = m->mount_opt; #endif - } else if (token == Opt_dax) { + } else if (token == Opt_dax || token == Opt_dax_str) { #ifdef CONFIG_FS_DAX - ext4_msg(sb, KERN_WARNING, - "DAX enabled. Warning: EXPERIMENTAL, use at your own risk"); - sbi->s_mount_opt |= m->mount_opt; + char *tmp = match_strdup(&args[0]); + + if (!tmp || !strcmp(tmp, "always")) { + ext4_msg(sb, KERN_WARNING, + "DAX enabled. Warning: EXPERIMENTAL, use at your own risk"); + sbi->s_mount_opt |= EXT4_MOUNT_DAX; + sbi->s_mount_opt2 &= ~EXT4_MOUNT2_NODAX; + } else if (!strcmp(tmp, "never")) { + sbi->s_mount_opt2 |= EXT4_MOUNT2_NODAX; + sbi->s_mount_opt &= ~EXT4_MOUNT_DAX; + } else if (!strcmp(tmp, "inode")) { + sbi->s_mount_opt &= ~EXT4_MOUNT_DAX; + sbi->s_mount_opt2 &= ~EXT4_MOUNT2_NODAX; + } else { + ext4_msg(sb, KERN_WARNING, "DAX invalid option."); + kfree(tmp); + return -1; + } + + kfree(tmp); #else ext4_msg(sb, KERN_INFO, "dax option not supported"); + sbi->s_mount_opt2 |= EXT4_MOUNT2_NODAX; + sbi->s_mount_opt &= ~EXT4_MOUNT_DAX; return -1; #endif } else if (token == Opt_data_err_abort) { @@ -2303,6 +2325,13 @@ static int _ext4_show_options(struct seq_file *seq, struct super_block *sb, if (DUMMY_ENCRYPTION_ENABLED(sbi)) SEQ_OPTS_PUTS("test_dummy_encryption"); + if (test_opt2(sb, NODAX)) + SEQ_OPTS_PUTS("dax=never"); + else if (test_opt(sb, DAX)) + SEQ_OPTS_PUTS("dax=always"); + else + SEQ_OPTS_PUTS("dax=inode"); + ext4_show_quota_options(seq, sb); return 0; } @@ -5424,6 +5453,12 @@ static int ext4_remount(struct super_block *sb, int *flags, char *data) sbi->s_mount_opt ^= EXT4_MOUNT_DAX; } + if ((sbi->s_mount_opt2 ^ old_opts.s_mount_opt2) & EXT4_MOUNT2_NODAX) { + ext4_msg(sb, KERN_WARNING, "warning: refusing change of " + "non-dax flag with busy inodes while remounting"); + sbi->s_mount_opt2 ^= EXT4_MOUNT2_NODAX; + } + if (sbi->s_mount_flags & EXT4_MF_FS_ABORTED) ext4_abort(sb, "Abort forced by user"); -- 2.25.1
