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authorRussell King <rmk+kernel@armlinux.org.uk>2019-12-09 11:08:18 +0000
committerAl Viro <viro@zeniv.linux.org.uk>2020-01-20 20:12:40 -0500
commiteeeb9dd98ec353a19988b010223f29a8783127fa (patch)
treef05e0df006b5243254612e0958793c3080bdae0b /fs/adfs
parente42617b825f8073569da76dc4510bfa019b1c35a (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')
-rw-r--r--fs/adfs/inode.c40
-rw-r--r--fs/adfs/super.c2
2 files changed, 22 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?
diff --git a/fs/adfs/super.c b/fs/adfs/super.c
index 65b04ebb51c3..e0eea9adb4e6 100644
--- a/fs/adfs/super.c
+++ b/fs/adfs/super.c
@@ -391,7 +391,9 @@ static int adfs_fill_super(struct super_block *sb, void *data, int silent)
asb = kzalloc(sizeof(*asb), GFP_KERNEL);
if (!asb)
return -ENOMEM;
+
sb->s_fs_info = asb;
+ sb->s_time_gran = 10000000;
/* set default options */
asb->s_uid = GLOBAL_ROOT_UID;