diff options
| author | Russell King <rmk+kernel@armlinux.org.uk> | 2019-12-09 11:08:18 +0000 |
|---|---|---|
| committer | Al Viro <viro@zeniv.linux.org.uk> | 2020-01-20 20:12:40 -0500 |
| commit | eeeb9dd98ec353a19988b010223f29a8783127fa (patch) | |
| tree | f05e0df006b5243254612e0958793c3080bdae0b /fs/adfs/inode.c | |
| parent | e42617b825f8073569da76dc4510bfa019b1c35a (diff) | |
fs/adfs: inode: update timestamps to centisecond precision
Despite ADFS timestamps having centi-second granularity, and Linux
gaining fine-grained timestamp support in v2.5.48, fs/adfs was never
updated.
Update fs/adfs to centi-second support, and ensure that the inode ctime
always reflects what is written in underlying media.
Signed-off-by: Russell King <rmk+kernel@armlinux.org.uk>
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
Diffstat (limited to 'fs/adfs/inode.c')
| -rw-r--r-- | fs/adfs/inode.c | 40 |
1 files changed, 20 insertions, 20 deletions
diff --git a/fs/adfs/inode.c b/fs/adfs/inode.c index 124de75413a5..18a1d478669b 100644 --- a/fs/adfs/inode.c +++ b/fs/adfs/inode.c @@ -158,6 +158,8 @@ adfs_mode2atts(struct super_block *sb, struct inode *inode) return attr; } +static const s64 nsec_unix_epoch_diff_risc_os_epoch = 2208988800000000000LL; + /* * Convert an ADFS time to Unix time. ADFS has a 40-bit centi-second time * referenced to 1 Jan 1900 (til 2248) so we need to discard 2208988800 seconds @@ -170,8 +172,6 @@ adfs_adfs2unix_time(struct timespec64 *tv, struct inode *inode) /* 01 Jan 1970 00:00:00 (Unix epoch) as nanoseconds since * 01 Jan 1900 00:00:00 (RISC OS epoch) */ - static const s64 nsec_unix_epoch_diff_risc_os_epoch = - 2208988800000000000LL; s64 nsec; if (!adfs_inode_is_stamped(inode)) @@ -204,24 +204,23 @@ adfs_adfs2unix_time(struct timespec64 *tv, struct inode *inode) return; } -/* - * Convert an Unix time to ADFS time. We only do this if the entry has a - * time/date stamp already. - */ -static void -adfs_unix2adfs_time(struct inode *inode, unsigned int secs) +/* Convert an Unix time to ADFS time for an entry that is already stamped. */ +static void adfs_unix2adfs_time(struct inode *inode, + const struct timespec64 *ts) { - unsigned int high, low; + s64 cs, nsec = timespec64_to_ns(ts); - if (adfs_inode_is_stamped(inode)) { - /* convert 32-bit seconds to 40-bit centi-seconds */ - low = (secs & 255) * 100; - high = (secs / 256) * 100 + (low >> 8) + 0x336e996a; + /* convert from Unix to RISC OS epoch */ + nsec += nsec_unix_epoch_diff_risc_os_epoch; - ADFS_I(inode)->loadaddr = (high >> 24) | - (ADFS_I(inode)->loadaddr & ~0xff); - ADFS_I(inode)->execaddr = (low & 255) | (high << 8); - } + /* convert from nanoseconds to centiseconds */ + cs = div_s64(nsec, 10000000); + + cs = clamp_t(s64, cs, 0, 0xffffffffff); + + ADFS_I(inode)->loadaddr &= ~0xff; + ADFS_I(inode)->loadaddr |= (cs >> 32) & 0xff; + ADFS_I(inode)->execaddr = cs; } /* @@ -315,10 +314,11 @@ adfs_notify_change(struct dentry *dentry, struct iattr *attr) if (ia_valid & ATTR_SIZE) truncate_setsize(inode, attr->ia_size); - if (ia_valid & ATTR_MTIME) { - inode->i_mtime = attr->ia_mtime; - adfs_unix2adfs_time(inode, attr->ia_mtime.tv_sec); + if (ia_valid & ATTR_MTIME && adfs_inode_is_stamped(inode)) { + adfs_unix2adfs_time(inode, &attr->ia_mtime); + adfs_adfs2unix_time(&inode->i_mtime, inode); } + /* * FIXME: should we make these == to i_mtime since we don't * have the ability to represent them in our filesystem? |