From: Lukas Czerner <lczerner@xxxxxxxxxx> [ Upstream commit f25391ebb475d3ffb3aa61bb90e3594c841749ef ] Currently there is a problem with mount options that can be both set by vfs using mount flags or by a string parsing in ext4. i_version/iversion options gets lost after remount, for example $ mount -o i_version /dev/pmem0 /mnt $ grep pmem0 /proc/self/mountinfo | grep i_version 310 95 259:0 / /mnt rw,relatime shared:163 - ext4 /dev/pmem0 rw,seclabel,i_version $ mount -o remount,ro /mnt $ grep pmem0 /proc/self/mountinfo | grep i_version nolazytime gets ignored by ext4 on remount, for example $ mount -o lazytime /dev/pmem0 /mnt $ grep pmem0 /proc/self/mountinfo | grep lazytime 310 95 259:0 / /mnt rw,relatime shared:163 - ext4 /dev/pmem0 rw,lazytime,seclabel $ mount -o remount,nolazytime /mnt $ grep pmem0 /proc/self/mountinfo | grep lazytime 310 95 259:0 / /mnt rw,relatime shared:163 - ext4 /dev/pmem0 rw,lazytime,seclabel Fix it by applying the SB_LAZYTIME and SB_I_VERSION flags from *flags to s_flags before we parse the option and use the resulting state of the same flags in *flags at the end of successful remount. Signed-off-by: Lukas Czerner <lczerner@xxxxxxxxxx> Reviewed-by: Ritesh Harjani <riteshh@xxxxxxxxxxxxx> Link: https://lore.kernel.org/r/20200723150526.19931-1-lczerner@xxxxxxxxxx Signed-off-by: Theodore Ts'o <tytso@xxxxxxx> Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx> --- fs/ext4/super.c | 21 ++++++++++++++++----- 1 file changed, 16 insertions(+), 5 deletions(-) diff --git a/fs/ext4/super.c b/fs/ext4/super.c index 23ef8fbdb582f..03ebb0b385467 100644 --- a/fs/ext4/super.c +++ b/fs/ext4/super.c @@ -5249,7 +5249,7 @@ static int ext4_remount(struct super_block *sb, int *flags, char *data) { struct ext4_super_block *es; struct ext4_sb_info *sbi = EXT4_SB(sb); - unsigned long old_sb_flags; + unsigned long old_sb_flags, vfs_flags; struct ext4_mount_options old_opts; int enable_quota = 0; ext4_group_t g; @@ -5292,6 +5292,14 @@ static int ext4_remount(struct super_block *sb, int *flags, char *data) if (sbi->s_journal && sbi->s_journal->j_task->io_context) journal_ioprio = sbi->s_journal->j_task->io_context->ioprio; + /* + * Some options can be enabled by ext4 and/or by VFS mount flag + * either way we need to make sure it matches in both *flags and + * s_flags. Copy those selected flags from *flags to s_flags + */ + vfs_flags = SB_LAZYTIME | SB_I_VERSION; + sb->s_flags = (sb->s_flags & ~vfs_flags) | (*flags & vfs_flags); + if (!parse_options(data, sb, NULL, &journal_ioprio, 1)) { err = -EINVAL; goto restore_opts; @@ -5345,9 +5353,6 @@ static int ext4_remount(struct super_block *sb, int *flags, char *data) set_task_ioprio(sbi->s_journal->j_task, journal_ioprio); } - if (*flags & SB_LAZYTIME) - sb->s_flags |= SB_LAZYTIME; - if ((bool)(*flags & SB_RDONLY) != sb_rdonly(sb)) { if (sbi->s_mount_flags & EXT4_MF_FS_ABORTED) { err = -EROFS; @@ -5487,7 +5492,13 @@ static int ext4_remount(struct super_block *sb, int *flags, char *data) } #endif - *flags = (*flags & ~SB_LAZYTIME) | (sb->s_flags & SB_LAZYTIME); + /* + * Some options can be enabled by ext4 and/or by VFS mount flag + * either way we need to make sure it matches in both *flags and + * s_flags. Copy those selected flags from s_flags to *flags + */ + *flags = (*flags & ~vfs_flags) | (sb->s_flags & vfs_flags); + ext4_msg(sb, KERN_INFO, "re-mounted. Opts: %s", orig_data); kfree(orig_data); return 0; -- 2.25.1
