| Message ID | 20200723150526.19931-1-lczerner@redhat.com |
|---|---|
| State | Awaiting Upstream |
| Headers | show |
| Series | ext4: handle option set by mount flags correctly | expand |
On 7/23/20 8:35 PM, Lukas Czerner wrote: > 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@redhat.com> Looks good to me. I did some small unit testing to observe the behavior. Below logs are *with your patch applied* for nolazytime e.g. which you referred above. But without your patch, as you mentioned nolazytime was not taking into effect. mount 8635 [007] 5477.595642: probe:ext4_remount: (ffffffff813bd270) s_flags=0x72810000 flags=0x0 data_string="i_version" mount 8635 [007] 5477.595672: probe:ext4_remount_L55: (ffffffff813bd3d1) s_flags=0x70010000 flags=0x0 data_string="i_version" mount 8635 [007] 5477.595758: probe:ext4_remount_L217: (ffffffff813bd787) s_flags=0x70810000 flags=0x0 mount 8635 [007] 5477.595772: probe:ext4_remount_L246: (ffffffff813bd820) s_flags=0x70810000 flags=0x800000 Please feel free to add. Reviewed-by: Ritesh Harjani <riteshh@linux.ibm.com> > --- > 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 330957ed1f05..caab4c57f909 100644 > --- a/fs/ext4/super.c > +++ b/fs/ext4/super.c > @@ -5445,7 +5445,7 @@ 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; > @@ -5488,6 +5488,14 @@ 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; > @@ -5541,9 +5549,6 @@ 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; > @@ -5675,7 +5680,13 @@ 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; >
On Thu, Jul 23, 2020 at 05:05:26PM +0200, Lukas Czerner wrote: > 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@redhat.com> Thanks, applied. - Ted
diff --git a/fs/ext4/super.c b/fs/ext4/super.c index 330957ed1f05..caab4c57f909 100644 --- a/fs/ext4/super.c +++ b/fs/ext4/super.c @@ -5445,7 +5445,7 @@ 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; @@ -5488,6 +5488,14 @@ 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; @@ -5541,9 +5549,6 @@ 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; @@ -5675,7 +5680,13 @@ 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;
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@redhat.com> --- fs/ext4/super.c | 21 ++++++++++++++++----- 1 file changed, 16 insertions(+), 5 deletions(-)