From: Frank Sorenson <sorenson@xxxxxxxxxx> Subject: fat: add functions to update and truncate timestamps appropriately Add the fat-specific inode_operation ->update_time() and fat_truncate_time() function to truncate the inode timestamps from 1 nanosecond to the appropriate granularity. Link: http://lkml.kernel.org/r/38af1ba3c3cf0d7381ce7b63077ef8af75901532.1538363961.git.sorenson@xxxxxxxxxx Signed-off-by: Frank Sorenson <sorenson@xxxxxxxxxx> Acked-by: OGAWA Hirofumi <hirofumi@xxxxxxxxxxxxxxxxxx> Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx> --- fs/fat/fat.h | 4 ++ fs/fat/file.c | 1 fs/fat/inode.c | 5 ++ fs/fat/misc.c | 75 +++++++++++++++++++++++++++++++++++++++++ fs/fat/namei_msdos.c | 1 fs/fat/namei_vfat.c | 1 6 files changed, 87 insertions(+) --- a/fs/fat/fat.h~fat-add-functions-to-update-and-truncate-timestamps-appropriately +++ a/fs/fat/fat.h @@ -416,6 +416,10 @@ extern void fat_time_fat2unix(struct msd __le16 __time, __le16 __date, u8 time_cs); extern void fat_time_unix2fat(struct msdos_sb_info *sbi, struct timespec64 *ts, __le16 *time, __le16 *date, u8 *time_cs); +extern int fat_truncate_time(struct inode *inode, struct timespec64 *now, + int flags); +extern int fat_update_time(struct inode *inode, struct timespec64 *now, + int flags); extern int fat_sync_bhs(struct buffer_head **bhs, int nr_bhs); int fat_cache_init(void); --- a/fs/fat/file.c~fat-add-functions-to-update-and-truncate-timestamps-appropriately +++ a/fs/fat/file.c @@ -552,4 +552,5 @@ EXPORT_SYMBOL_GPL(fat_setattr); const struct inode_operations fat_file_inode_operations = { .setattr = fat_setattr, .getattr = fat_getattr, + .update_time = fat_update_time, }; --- a/fs/fat/inode.c~fat-add-functions-to-update-and-truncate-timestamps-appropriately +++ a/fs/fat/inode.c @@ -1626,6 +1626,11 @@ int fat_fill_super(struct super_block *s sb->s_magic = MSDOS_SUPER_MAGIC; sb->s_op = &fat_sops; sb->s_export_op = &fat_export_ops; + /* + * fat timestamps are complex and truncated by fat itself, so + * we set 1 here to be fast + */ + sb->s_time_gran = 1; mutex_init(&sbi->nfs_build_inode_lock); ratelimit_state_init(&sbi->ratelimit, DEFAULT_RATELIMIT_INTERVAL, DEFAULT_RATELIMIT_BURST); --- a/fs/fat/misc.c~fat-add-functions-to-update-and-truncate-timestamps-appropriately +++ a/fs/fat/misc.c @@ -7,6 +7,7 @@ */ #include "fat.h" +#include <linux/iversion.h> /* * fat_fs_error reports a file system problem that might indicate fa data @@ -265,6 +266,80 @@ void fat_time_unix2fat(struct msdos_sb_i } EXPORT_SYMBOL_GPL(fat_time_unix2fat); +static inline struct timespec64 fat_timespec64_trunc_2secs(struct timespec64 ts) +{ + return (struct timespec64){ ts.tv_sec & ~1ULL, 0 }; +} +/* + * truncate the various times with appropriate granularity: + * root inode: + * all times always 0 + * all other inodes: + * mtime - 2 seconds + * ctime + * msdos - 2 seconds + * vfat - 10 milliseconds + * atime - 24 hours (00:00:00 in local timezone) + */ +int fat_truncate_time(struct inode *inode, struct timespec64 *now, int flags) +{ + struct msdos_sb_info *sbi = MSDOS_SB(inode->i_sb); + struct timespec64 ts; + + if (inode->i_ino == MSDOS_ROOT_INO) + return 0; + + if (now == NULL) { + now = &ts; + ts = current_time(inode); + } + + if (flags & S_ATIME) { + /* to localtime */ + time64_t seconds = now->tv_sec - fat_tz_offset(sbi); + s32 remainder; + + div_s64_rem(seconds, SECS_PER_DAY, &remainder); + /* to day boundary, and back to unix time */ + seconds = seconds + fat_tz_offset(sbi) - remainder; + + inode->i_atime = (struct timespec64){ seconds, 0 }; + } + if (flags & S_CTIME) { + if (sbi->options.isvfat) + inode->i_ctime = timespec64_trunc(*now, 10000000); + else + inode->i_ctime = fat_timespec64_trunc_2secs(*now); + } + if (flags & S_MTIME) + inode->i_mtime = fat_timespec64_trunc_2secs(*now); + + return 0; +} +EXPORT_SYMBOL_GPL(fat_truncate_time); + +int fat_update_time(struct inode *inode, struct timespec64 *now, int flags) +{ + int iflags = I_DIRTY_TIME; + bool dirty = false; + + if (inode->i_ino == MSDOS_ROOT_INO) + return 0; + + fat_truncate_time(inode, now, flags); + if (flags & S_VERSION) + dirty = inode_maybe_inc_iversion(inode, false); + if ((flags & (S_ATIME | S_CTIME | S_MTIME)) && + !(inode->i_sb->s_flags & SB_LAZYTIME)) + dirty = true; + + if (dirty) + iflags |= I_DIRTY_SYNC; + __mark_inode_dirty(inode, iflags); + return 0; +} +EXPORT_SYMBOL_GPL(fat_update_time); + int fat_sync_bhs(struct buffer_head **bhs, int nr_bhs) { int i, err = 0; --- a/fs/fat/namei_msdos.c~fat-add-functions-to-update-and-truncate-timestamps-appropriately +++ a/fs/fat/namei_msdos.c @@ -637,6 +637,7 @@ static const struct inode_operations msd .rename = msdos_rename, .setattr = fat_setattr, .getattr = fat_getattr, + .update_time = fat_update_time, }; static void setup(struct super_block *sb) --- a/fs/fat/namei_vfat.c~fat-add-functions-to-update-and-truncate-timestamps-appropriately +++ a/fs/fat/namei_vfat.c @@ -1032,6 +1032,7 @@ static const struct inode_operations vfa .rename = vfat_rename, .setattr = fat_setattr, .getattr = fat_getattr, + .update_time = fat_update_time, }; static void setup(struct super_block *sb) _
