Slava Bacherikov <slava@xxxxxxxxxxxx> writes:
> Casefold can be safely disabled if there are no directories with +F
> attribute ( EXT4_CASEFOLD_FL ). This checks all inodes for that flag and in
> case there isn't any, it disables casefold FS feature. When FS has
> directories with +F attributes, user could convert these directories,
> probably by mounting FS and executing some script or by doing it
> manually. Afterwards, it would be possible to disable casefold FS flag
> via tune2fs.
>
> Signed-off-by: Slava Bacherikov <slava@xxxxxxxxxxxx>
I think this is a safe thing to do, gave it a quick spin and the patch
now looks good to me.
Reviewed-by: Gabriel Krisman Bertazi <krisman@xxxxxxxxxxxxx>
Thank you,
> ---
> misc/tune2fs.8.in | 6 ++++--
> misc/tune2fs.c | 54 ++++++++++++++++++++++++++++++++++++++++++++++-
> 2 files changed, 57 insertions(+), 3 deletions(-)
>
> diff --git a/misc/tune2fs.8.in b/misc/tune2fs.8.in
> index 628dcdc0..dcf108c1 100644
> --- a/misc/tune2fs.8.in
> +++ b/misc/tune2fs.8.in
> @@ -593,8 +593,10 @@ Enable the file system to be larger than 2^32 blocks.
> .TP
> .B casefold
> Enable support for file system level casefolding.
> -.B Tune2fs
> -currently only supports setting this file system feature.
> +The option can be cleared only if filesystem has no
> +directories with
> +.B F
> +attribute.
> .TP
> .B dir_index
> Use hashed b-trees to speed up lookups for large directories.
> diff --git a/misc/tune2fs.c b/misc/tune2fs.c
> index 6c162ba5..a8355619 100644
> --- a/misc/tune2fs.c
> +++ b/misc/tune2fs.c
> @@ -204,7 +204,8 @@ static __u32 clear_ok_features[3] = {
> EXT4_FEATURE_INCOMPAT_FLEX_BG |
> EXT4_FEATURE_INCOMPAT_MMP |
> EXT4_FEATURE_INCOMPAT_64BIT |
> - EXT4_FEATURE_INCOMPAT_CSUM_SEED,
> + EXT4_FEATURE_INCOMPAT_CSUM_SEED |
> + EXT4_FEATURE_INCOMPAT_CASEFOLD,
> /* R/O compat */
> EXT2_FEATURE_RO_COMPAT_LARGE_FILE |
> EXT4_FEATURE_RO_COMPAT_HUGE_FILE|
> @@ -1020,6 +1021,41 @@ out:
> return retval;
> }
>
> +static int has_casefold_inode(ext2_filsys fs)
> +{
> + int length = EXT2_INODE_SIZE(fs->super);
> + struct ext2_inode *inode = NULL;
> + ext2_inode_scan scan;
> + errcode_t retval;
> + ext2_ino_t ino;
> + int found_casefold = 0;
> +
> + retval = ext2fs_get_mem(length, &inode);
> + if (retval)
> + fatal_err(retval, "while allocating memory");
> +
> + retval = ext2fs_open_inode_scan(fs, 0, &scan);
> + if (retval)
> + fatal_err(retval, "while opening inode scan");
> +
> + do {
> + retval = ext2fs_get_next_inode_full(scan, &ino, inode, length);
> + if (retval)
> + fatal_err(retval, "while getting next inode");
> + if (!ino)
> + break;
> +
> + if(inode->i_flags & EXT4_CASEFOLD_FL) {
> + found_casefold = 1;
> + break;
> + }
> + } while(1);
> +
> + ext2fs_free_mem(&inode);
> + ext2fs_close_inode_scan(scan);
> + return found_casefold;
> +}
> +
> static errcode_t disable_uninit_bg(ext2_filsys fs, __u32 csum_feature_flag)
> {
> struct ext2_group_desc *gd;
> @@ -1554,6 +1590,22 @@ mmp_error:
> enabling_casefold = 1;
> }
>
> + if (FEATURE_OFF(E2P_FEATURE_INCOMPAT, EXT4_FEATURE_INCOMPAT_CASEFOLD)) {
> + if (mount_flags & EXT2_MF_MOUNTED) {
> + fputs(_("The casefold feature may only be disabled when "
> + "the filesystem is unmounted.\n"), stderr);
> + return 1;
> + }
> + if (has_casefold_inode(fs)) {
> + fputs(_("The casefold feature can't be cleared when "
> + "there are inodes with +F flag.\n"), stderr);
> + return 1;
> + }
> + fs->super->s_encoding = 0;
> + fs->super->s_encoding_flags = 0;
> + enabling_casefold = 0;
> + }
> +
> if (FEATURE_ON(E2P_FEATURE_INCOMPAT,
> EXT4_FEATURE_INCOMPAT_CSUM_SEED)) {
> if (!ext2fs_has_feature_metadata_csum(sb)) {
--
Gabriel Krisman Bertazi
