On Tue, 2009-08-04 at 12:32 +0200, ext OGAWA Hirofumi wrote:
> Jörg Schummer <[email protected]> writes:
>
> > On Mon, 2009-07-27 at 13:47 +0200, ext OGAWA Hirofumi wrote:
> >> Jörg Schummer <[email protected]> writes:
> >
> >> BTW, the patch has several bugs. fat_get_label_entry() doesn't check
> >> IS_FREE(), is it right? fat_create_label_entry() doesn't initialize all
> >> timestamp in the case of msdos. spin_lock() usage is wrong. and more...
> >
> > After reviewing the patch again, I did notice some additional problems
> > (I suppose that was the "and more..."). If and when I have time again, I
> > might take a closer look at it again.
> >
> > Thanks for your help until now!
Hello,
on the off-chance that somebody would like to use this mechanism, I did
a 3rd take of the patch. I tried to fix the problems of the previous
patch and additionally added the functionality to correct the root dir
timestamp's mtime and atime somewhat based on contained directory
entries' ctime.
Any comments are welcome, but especially I'd like to ask if it is safe /
good / doable to call
remove_inode_hash(inode);
fat_attach(inode, i_pos);
insert_inode_hash(inode);
inside fat_write_inode .
Thanks for any feedback!
Jörg
Standard FAT implementations cannot store any of the FAT root directory's
timestamps. This commit adds the mount option 'rootts', which allows saving
the FAT root directory timestamps as the timestamps of the FAT volume label
directory entry. At least Mac OS X is known to support the same mechanism
and interoperate with this commit.
When mounting, the following values can be specified for the 'rootts' mount
option:
"rootts=ignore" ignores root directory timestamps. All timestamps are
reset to 0 (1/1/1970). This has been the FAT behaviour
prior to this patch.
"rootts=preserve" tries to load and save the root directory's timestamps
if a volume label entry exists. The mtime and atime are
corrected based on root directory entries' ctime. This
is the default.
"rootts=save" tries to load and save the root directory's timestamps.
The mtime and atime are corrected based on root
directory entries' ctime. If the root directory was
accessed but no volume label entry exists, the label
"NO NAME" is created.
Signed-off-by: Jorg Schummer <[email protected]>
---
Documentation/filesystems/vfat.txt | 9 ++
fs/fat/dir.c | 75 ++++++++++++++
fs/fat/fat.h | 19 ++++
fs/fat/inode.c | 192 +++++++++++++++++++++++++-----------
4 files changed, 239 insertions(+), 56 deletions(-)
diff --git a/Documentation/filesystems/vfat.txt b/Documentation/filesystems/vfat.txt
index b58b84b..64f6509 100644
--- a/Documentation/filesystems/vfat.txt
+++ b/Documentation/filesystems/vfat.txt
@@ -137,6 +137,15 @@ errors=panic|continue|remount-ro
without doing anything or remount the partition in
read-only mode (default behavior).
+rootts=ignore|preserve|save
+ -- Specify whether to load/store the root dir timestamps as the
+ timestamp of the volume label entry.
+ ignore: do not load or store root dir ts.
+ preserve: load the root dir ts, store them only if a volume
+ label already exists. This is the default.
+ save: load and store the root dir ts, create a volume label
+ if the ts have changed but no label is present.
+
<bool>: 0,1,yes,no,true,false
TODO
diff --git a/fs/fat/dir.c b/fs/fat/dir.c
index 530b4ca..114e748 100644
--- a/fs/fat/dir.c
+++ b/fs/fat/dir.c
@@ -1362,3 +1362,78 @@ error_remove:
}
EXPORT_SYMBOL_GPL(fat_add_entries);
+
+int fat_get_label_entry(struct inode *root_inode, struct buffer_head **bh,
+ struct msdos_dir_entry **de, loff_t *i_pos)
+{
+ loff_t offset;
+
+ BUG_ON(root_inode->i_ino != MSDOS_ROOT_INO);
+
+ offset = 0;
+ *bh = NULL;
+ while (fat_get_entry(root_inode, &offset, bh, de) >= 0) {
+ /* not free and volume label */
+ if (!IS_FREE((*de)->name) && (*de)->attr != ATTR_EXT &&
+ ((*de)->attr & ATTR_VOLUME)) {
+ *i_pos = fat_make_i_pos(root_inode->i_sb, *bh, *de);
+ return 0;
+ }
+ }
+ return -ENOENT;
+}
+EXPORT_SYMBOL_GPL(fat_get_label_entry);
+
+int fat_add_label_entry(struct inode *root_inode, const unsigned char *name)
+{
+ struct msdos_dir_entry de;
+ struct fat_slot_info sinfo;
+ int err;
+
+ BUG_ON(root_inode->i_ino != MSDOS_ROOT_INO);
+
+ memcpy(de.name,
+ (name) ? name : (const unsigned char *) FAT_LABEL_NONAME,
+ MSDOS_NAME);
+ de.attr = ATTR_VOLUME;
+ de.lcase = 0;
+ de.start = de.starthi = 0;
+ de.size = 0;
+ de.time = de.ctime = 0;
+ de.ctime_cs = 0;
+ de.date = de.adate = de.cdate = 0;
+
+ err = fat_add_entries(root_inode, &de, 1, &sinfo);
+ brelse(sinfo.bh);
+
+ return err;
+}
+EXPORT_SYMBOL_GPL(fat_add_label_entry);
+
+void fat_correct_root_ts(struct inode *root_inode)
+{
+ struct msdos_sb_info *sbi = MSDOS_SB(root_inode->i_sb);
+ struct buffer_head *bh;
+ struct msdos_dir_entry *de;
+ struct timespec ts;
+ loff_t offset;
+
+ BUG_ON(root_inode->i_ino != MSDOS_ROOT_INO);
+
+ offset = 0;
+ bh = NULL;
+ while (fat_get_entry(root_inode, &offset, &bh, &de) >= 0) {
+ /* not free and short entry, not a volume label */
+ if (!IS_FREE(de->name) &&
+ de->attr != ATTR_EXT && !(de->attr & ATTR_VOLUME)) {
+ fat_time_fat2unix(sbi, &ts, de->ctime,
+ de->cdate, de->ctime_cs);
+ if (timespec_compare(&root_inode->i_mtime, &ts) < 0)
+ root_inode->i_mtime = ts;
+ }
+ }
+
+ if (timespec_compare(&root_inode->i_mtime, &root_inode->i_atime) > 0)
+ root_inode->i_atime = root_inode->i_mtime;
+}
+EXPORT_SYMBOL_GPL(fat_correct_root_ts);
diff --git a/fs/fat/fat.h b/fs/fat/fat.h
index adb0e72..27bc46d 100644
--- a/fs/fat/fat.h
+++ b/fs/fat/fat.h
@@ -21,6 +21,14 @@
#define FAT_ERRORS_PANIC 2 /* panic on error */
#define FAT_ERRORS_RO 3 /* remount r/o on error */
+/*
+ * fat root directory timestamp backup
+ */
+#define FAT_ROOT_TS_IGNORE 1 /* do not read or write root dir ts */
+#define FAT_ROOT_TS_PRESERVE 2 /* read and write root dir ts as volume label
+ timestamp */
+#define FAT_ROOT_TS_SAVE 3 /* create volume label if there is none */
+
struct fat_mount_options {
uid_t fs_uid;
gid_t fs_gid;
@@ -32,6 +40,8 @@ struct fat_mount_options {
unsigned char name_check; /* r = relaxed, n = normal, s = strict */
unsigned char errors; /* On error: continue, panic, remount-ro */
unsigned short allow_utime;/* permission for setting the [am]time */
+ unsigned short root_ts; /* root dir timestamps:
+ ignore, preserve, save */
unsigned quiet:1, /* set = fake successful chmods and chowns */
showexec:1, /* set = only set x bit for com/exe/bat */
sys_immutable:1, /* set = system files are immutable */
@@ -50,6 +60,8 @@ struct fat_mount_options {
#define FAT_HASH_BITS 8
#define FAT_HASH_SIZE (1UL << FAT_HASH_BITS)
+#define FAT_LABEL_NONAME "NO NAME "
+
/*
* MS-DOS file system in-core superblock data
*/
@@ -247,6 +259,13 @@ extern int fat_add_entries(struct inode *dir, void *slots, int nr_slots,
struct fat_slot_info *sinfo);
extern int fat_remove_entries(struct inode *dir, struct fat_slot_info *sinfo);
+extern int fat_get_label_entry(struct inode *root_inode,
+ struct buffer_head **bh,
+ struct msdos_dir_entry **de, loff_t *i_pos);
+extern int fat_add_label_entry(struct inode *root_inode,
+ const unsigned char *name);
+extern void fat_correct_root_ts(struct inode *root_inode);
+
/* fat/fatent.c */
struct fat_entry {
int entry;
diff --git a/fs/fat/inode.c b/fs/fat/inode.c
index 8970d8c..0ba0e0c 100644
--- a/fs/fat/inode.c
+++ b/fs/fat/inode.c
@@ -330,35 +330,62 @@ static int fat_calc_dir_size(struct inode *inode)
return 0;
}
-/* doesn't deal with root inode */
+/* nowadays, this deals also with the root inode */
static int fat_fill_inode(struct inode *inode, struct msdos_dir_entry *de)
{
struct msdos_sb_info *sbi = MSDOS_SB(inode->i_sb);
int error;
+ __u8 attr;
+ int is_root = (inode->i_ino == MSDOS_ROOT_INO);
+
+ if (is_root)
+ attr = ATTR_DIR;
+ else
+ attr = de->attr;
MSDOS_I(inode)->i_pos = 0;
inode->i_uid = sbi->options.fs_uid;
inode->i_gid = sbi->options.fs_gid;
inode->i_version++;
- inode->i_generation = get_seconds();
+ if (is_root)
+ inode->i_generation = 0;
+ else
+ inode->i_generation = get_seconds();
- if ((de->attr & ATTR_DIR) && !IS_FREE(de->name)) {
- inode->i_generation &= ~1;
- inode->i_mode = fat_make_mode(sbi, de->attr, S_IRWXUGO);
+ if ((attr & ATTR_DIR) && (is_root || !IS_FREE(de->name))) {
+ if (!is_root)
+ inode->i_generation &= ~1;
+ inode->i_mode = fat_make_mode(sbi, attr, S_IRWXUGO);
inode->i_op = sbi->dir_ops;
inode->i_fop = &fat_dir_operations;
- MSDOS_I(inode)->i_start = le16_to_cpu(de->start);
- if (sbi->fat_bits == 32)
- MSDOS_I(inode)->i_start |= (le16_to_cpu(de->starthi) << 16);
-
- MSDOS_I(inode)->i_logstart = MSDOS_I(inode)->i_start;
- error = fat_calc_dir_size(inode);
+ if (is_root) {
+ if (sbi->fat_bits == 32) {
+ MSDOS_I(inode)->i_start = sbi->root_cluster;
+ error = fat_calc_dir_size(inode);
+ } else {
+ MSDOS_I(inode)->i_start = 0;
+ inode->i_size = sbi->dir_entries *
+ sizeof(struct msdos_dir_entry);
+ error = 0;
+ }
+ MSDOS_I(inode)->i_logstart = 0;
+ } else {
+ MSDOS_I(inode)->i_start = le16_to_cpu(de->start);
+ if (sbi->fat_bits == 32)
+ MSDOS_I(inode)->i_start |=
+ (le16_to_cpu(de->starthi) << 16);
+ MSDOS_I(inode)->i_logstart = MSDOS_I(inode)->i_start;
+ error = fat_calc_dir_size(inode);
+ }
if (error < 0)
return error;
MSDOS_I(inode)->mmu_private = inode->i_size;
inode->i_nlink = fat_subdirs(inode);
+ if (is_root)
+ inode->i_nlink += 2;
+
} else { /* not a directory */
inode->i_generation |= 1;
inode->i_mode = fat_make_mode(sbi, de->attr,
@@ -375,22 +402,30 @@ static int fat_fill_inode(struct inode *inode, struct msdos_dir_entry *de)
inode->i_mapping->a_ops = &fat_aops;
MSDOS_I(inode)->mmu_private = inode->i_size;
}
- if (de->attr & ATTR_SYS) {
+ if (attr & ATTR_SYS) {
if (sbi->options.sys_immutable)
inode->i_flags |= S_IMMUTABLE;
}
- fat_save_attrs(inode, de->attr);
+ fat_save_attrs(inode, attr);
inode->i_blocks = ((inode->i_size + (sbi->cluster_size - 1))
& ~((loff_t)sbi->cluster_size - 1)) >> 9;
- fat_time_fat2unix(sbi, &inode->i_mtime, de->time, de->date, 0);
- if (sbi->options.isvfat) {
- fat_time_fat2unix(sbi, &inode->i_ctime, de->ctime,
- de->cdate, de->ctime_cs);
- fat_time_fat2unix(sbi, &inode->i_atime, 0, de->adate, 0);
- } else
- inode->i_ctime = inode->i_atime = inode->i_mtime;
+ if (!de) {
+ inode->i_mtime.tv_sec = inode->i_atime.tv_sec =
+ inode->i_ctime.tv_sec = 0;
+ inode->i_mtime.tv_nsec = inode->i_atime.tv_nsec =
+ inode->i_ctime.tv_nsec = 0;
+ } else {
+ fat_time_fat2unix(sbi, &inode->i_mtime, de->time, de->date, 0);
+ if (sbi->options.isvfat) {
+ fat_time_fat2unix(sbi, &inode->i_ctime, de->ctime,
+ de->cdate, de->ctime_cs);
+ fat_time_fat2unix(sbi, &inode->i_atime, 0,
+ de->adate, 0);
+ } else
+ inode->i_ctime = inode->i_atime = inode->i_mtime;
+ }
return 0;
}
@@ -590,8 +625,41 @@ static int fat_write_inode(struct inode *inode, int wait)
loff_t i_pos;
int err;
- if (inode->i_ino == MSDOS_ROOT_INO)
- return 0;
+ if (inode->i_ino == MSDOS_ROOT_INO) {
+ if (sbi->options.root_ts == FAT_ROOT_TS_IGNORE)
+ return 0;
+
+ /* Write the timestamps of a FAT file system's root directory
+ * as the timestamps of the file system's label dir entry. */
+
+ if (!MSDOS_I(inode)->i_pos) {
+ struct buffer_head *bh;
+ struct msdos_dir_entry *de;
+ loff_t i_pos;
+
+ if (sbi->options.root_ts != FAT_ROOT_TS_SAVE)
+ /* No label present, but we should not
+ create one. Thus not complaining. */
+ return 0;
+
+ printk(KERN_INFO "FAT: creating volume label "
+ "on %s to save root dir timestamps\n",
+ sb->s_id);
+
+ err = fat_add_label_entry(inode, NULL);
+ if (err)
+ return err;
+
+ err = fat_get_label_entry(inode, &bh, &de, &i_pos);
+ if (err)
+ return err;
+
+ remove_inode_hash(inode);
+ fat_attach(inode, i_pos);
+ insert_inode_hash(inode);
+ brelse(bh);
+ }
+ }
retry:
i_pos = fat_i_pos_read(sbi, inode);
@@ -613,13 +681,17 @@ retry:
raw_entry = &((struct msdos_dir_entry *) (bh->b_data))
[i_pos & (sbi->dir_per_block - 1)];
- if (S_ISDIR(inode->i_mode))
- raw_entry->size = 0;
- else
- raw_entry->size = cpu_to_le32(inode->i_size);
- raw_entry->attr = fat_make_attrs(inode);
- raw_entry->start = cpu_to_le16(MSDOS_I(inode)->i_logstart);
- raw_entry->starthi = cpu_to_le16(MSDOS_I(inode)->i_logstart >> 16);
+
+ if (inode->i_ino != MSDOS_ROOT_INO) {
+ if (S_ISDIR(inode->i_mode))
+ raw_entry->size = 0;
+ else
+ raw_entry->size = cpu_to_le32(inode->i_size);
+ raw_entry->attr = fat_make_attrs(inode);
+ raw_entry->start = cpu_to_le16(MSDOS_I(inode)->i_logstart);
+ raw_entry->starthi =
+ cpu_to_le16(MSDOS_I(inode)->i_logstart >> 16);
+ }
fat_time_unix2fat(sbi, &inode->i_mtime, &raw_entry->time,
&raw_entry->date, NULL);
if (sbi->options.isvfat) {
@@ -875,7 +947,8 @@ enum {
Opt_shortname_winnt, Opt_shortname_mixed, Opt_utf8_no, Opt_utf8_yes,
Opt_uni_xl_no, Opt_uni_xl_yes, Opt_nonumtail_no, Opt_nonumtail_yes,
Opt_obsolate, Opt_flush, Opt_tz_utc, Opt_rodir, Opt_err_cont,
- Opt_err_panic, Opt_err_ro, Opt_err,
+ Opt_err_panic, Opt_err_ro, Opt_rootts_ignore, Opt_rootts_preserve,
+ Opt_rootts_save, Opt_err,
};
static const match_table_t fat_tokens = {
@@ -903,6 +976,9 @@ static const match_table_t fat_tokens = {
{Opt_err_cont, "errors=continue"},
{Opt_err_panic, "errors=panic"},
{Opt_err_ro, "errors=remount-ro"},
+ {Opt_rootts_ignore, "rootts=ignore"},
+ {Opt_rootts_preserve, "rootts=preserve"},
+ {Opt_rootts_save, "rootts=save"},
{Opt_obsolate, "conv=binary"},
{Opt_obsolate, "conv=text"},
{Opt_obsolate, "conv=auto"},
@@ -984,6 +1060,7 @@ static int parse_options(char *options, int is_vfat, int silent, int *debug,
opts->usefree = opts->nocase = 0;
opts->tz_utc = 0;
opts->errors = FAT_ERRORS_RO;
+ opts->root_ts = FAT_ROOT_TS_PRESERVE;
*debug = 0;
if (!options)
@@ -1085,6 +1162,15 @@ static int parse_options(char *options, int is_vfat, int silent, int *debug,
case Opt_err_ro:
opts->errors = FAT_ERRORS_RO;
break;
+ case Opt_rootts_ignore:
+ opts->root_ts = FAT_ROOT_TS_IGNORE;
+ break;
+ case Opt_rootts_preserve:
+ opts->root_ts = FAT_ROOT_TS_PRESERVE;
+ break;
+ case Opt_rootts_save:
+ opts->root_ts = FAT_ROOT_TS_SAVE;
+ break;
/* msdos specific */
case Opt_dots:
@@ -1180,34 +1266,28 @@ static int fat_read_root(struct inode *inode)
struct msdos_sb_info *sbi = MSDOS_SB(sb);
int error;
- MSDOS_I(inode)->i_pos = 0;
- inode->i_uid = sbi->options.fs_uid;
- inode->i_gid = sbi->options.fs_gid;
- inode->i_version++;
- inode->i_generation = 0;
- inode->i_mode = fat_make_mode(sbi, ATTR_DIR, S_IRWXUGO);
- inode->i_op = sbi->dir_ops;
- inode->i_fop = &fat_dir_operations;
- if (sbi->fat_bits == 32) {
- MSDOS_I(inode)->i_start = sbi->root_cluster;
- error = fat_calc_dir_size(inode);
- if (error < 0)
- return error;
- } else {
- MSDOS_I(inode)->i_start = 0;
- inode->i_size = sbi->dir_entries * sizeof(struct msdos_dir_entry);
- }
- inode->i_blocks = ((inode->i_size + (sbi->cluster_size - 1))
- & ~((loff_t)sbi->cluster_size - 1)) >> 9;
- MSDOS_I(inode)->i_logstart = 0;
- MSDOS_I(inode)->mmu_private = inode->i_size;
+ error = fat_fill_inode(inode, NULL);
+
+ /* Try to restore the root dir's timestamps from the FAT volume label
+ entry */
+ if (!error && sbi->options.root_ts != FAT_ROOT_TS_IGNORE) {
+ struct buffer_head *bh;
+ struct msdos_dir_entry *de;
+ loff_t i_pos;
- fat_save_attrs(inode, ATTR_DIR);
- inode->i_mtime.tv_sec = inode->i_atime.tv_sec = inode->i_ctime.tv_sec = 0;
- inode->i_mtime.tv_nsec = inode->i_atime.tv_nsec = inode->i_ctime.tv_nsec = 0;
- inode->i_nlink = fat_subdirs(inode)+2;
+ error = fat_get_label_entry(inode, &bh, &de, &i_pos);
+ if (!error) {
+ error = fat_fill_inode(inode, de);
+ if (!error)
+ fat_attach(inode, i_pos);
+ brelse(bh);
+ } else if (error == -ENOENT)
+ error = 0;
- return 0;
+ fat_correct_root_ts(inode);
+ }
+
+ return error;
}
/*
--
1.5.4.3
Jorg Schummer wrote:
> Standard FAT implementations cannot store any of the FAT root directory's
> timestamps. This commit adds the mount option 'rootts', which allows saving
> the FAT root directory timestamps as the timestamps of the FAT volume label
> directory entry. At least Mac OS X is known to support the same mechanism
> and interoperate with this commit.
>
> When mounting, the following values can be specified for the 'rootts' mount
> option:
>
> "rootts=ignore" ignores root directory timestamps. All timestamps are
> reset to 0 (1/1/1970). This has been the FAT behaviour
> prior to this patch.
>
> "rootts=preserve" tries to load and save the root directory's timestamps
> if a volume label entry exists. The mtime and atime are
> corrected based on root directory entries' ctime. This
> is the default.
>
> "rootts=save" tries to load and save the root directory's timestamps.
> The mtime and atime are corrected based on root
> directory entries' ctime. If the root directory was
> accessed but no volume label entry exists, the label
> "NO NAME" is created.
Does Mac OS X do the same "NO NAME" thing?
-- Jamie
On Tue, 2009-09-08 at 17:39 +0200, ext Jamie Lokier wrote:
> Jorg Schummer wrote:
> > Standard FAT implementations cannot store any of the FAT root directory's
> > timestamps. This commit adds the mount option 'rootts', which allows saving
> > the FAT root directory timestamps as the timestamps of the FAT volume label
> > directory entry. At least Mac OS X is known to support the same mechanism
> > and interoperate with this commit.
> >
> > When mounting, the following values can be specified for the 'rootts' mount
> > option:
> >
> > "rootts=ignore" ignores root directory timestamps. All timestamps are
> > reset to 0 (1/1/1970). This has been the FAT behaviour
> > prior to this patch.
> >
> > "rootts=preserve" tries to load and save the root directory's timestamps
> > if a volume label entry exists. The mtime and atime are
> > corrected based on root directory entries' ctime. This
> > is the default.
> >
> > "rootts=save" tries to load and save the root directory's timestamps.
> > The mtime and atime are corrected based on root
> > directory entries' ctime. If the root directory was
> > accessed but no volume label entry exists, the label
> > "NO NAME" is created.
>
> Does Mac OS X do the same "NO NAME" thing?
AFAIK: No. It only supports the general mechanism of storing / loading
the root dir timestamps to / from the volume label entry.
But feel free to re-check that one.
Jörg
On Tue, 2009-09-08 at 16:34 +0200, Schummer Jorg.2
(EXT-TietoEnator/Helsinki) wrote:
> Standard FAT implementations cannot store any of the FAT root directory's
> timestamps. This commit adds the mount option 'rootts', which allows saving
> the FAT root directory timestamps as the timestamps of the FAT volume label
> directory entry. At least Mac OS X is known to support the same mechanism
> and interoperate with this commit.
>
> When mounting, the following values can be specified for the 'rootts' mount
> option:
>
> "rootts=ignore" ignores root directory timestamps. All timestamps are
> reset to 0 (1/1/1970). This has been the FAT behaviour
> prior to this patch.
>
> "rootts=preserve" tries to load and save the root directory's timestamps
> if a volume label entry exists. The mtime and atime are
> corrected based on root directory entries' ctime. This
> is the default.
>
> "rootts=save" tries to load and save the root directory's timestamps.
> The mtime and atime are corrected based on root
> directory entries' ctime. If the root directory was
> accessed but no volume label entry exists, the label
> "NO NAME" is created.
Hello again,
in case anyone would like to send some feedback or comments about the
patch, please use this email address from now on: [email protected] .
Thanks,
Jörg
Jorg Schummer <[email protected]> writes:
> Standard FAT implementations cannot store any of the FAT root directory's
> timestamps. This commit adds the mount option 'rootts', which allows saving
> the FAT root directory timestamps as the timestamps of the FAT volume label
> directory entry. At least Mac OS X is known to support the same mechanism
> and interoperate with this commit.
>
> When mounting, the following values can be specified for the 'rootts' mount
> option:
>
> "rootts=ignore" ignores root directory timestamps. All timestamps are
> reset to 0 (1/1/1970). This has been the FAT behaviour
> prior to this patch.
>
> "rootts=preserve" tries to load and save the root directory's timestamps
> if a volume label entry exists. The mtime and atime are
> corrected based on root directory entries' ctime. This
> is the default.
>
> "rootts=save" tries to load and save the root directory's timestamps.
> The mtime and atime are corrected based on root
> directory entries' ctime. If the root directory was
> accessed but no volume label entry exists, the label
> "NO NAME" is created.
Um..., I'm still not sure though. rootts=save may not be needed for
this, because it seems a bit complex, and it can do on userland...
And some quick review of implement..
> + if (inode->i_ino == MSDOS_ROOT_INO) {
> + if (sbi->options.root_ts == FAT_ROOT_TS_IGNORE)
> + return 0;
> +
> + /* Write the timestamps of a FAT file system's root directory
> + * as the timestamps of the file system's label dir entry. */
> +
> + if (!MSDOS_I(inode)->i_pos) {
> + struct buffer_head *bh;
> + struct msdos_dir_entry *de;
> + loff_t i_pos;
> +
> + if (sbi->options.root_ts != FAT_ROOT_TS_SAVE)
> + /* No label present, but we should not
> + create one. Thus not complaining. */
> + return 0;
> +
> + printk(KERN_INFO "FAT: creating volume label "
> + "on %s to save root dir timestamps\n",
> + sb->s_id);
> +
> + err = fat_add_label_entry(inode, NULL);
> + if (err)
> + return err;
> + err = fat_get_label_entry(inode, &bh, &de, &i_pos);
> + if (err)
> + return err;
In this path, we don't have inode->i_mutex, so to look directry up is
wrong. I think adding label may move to userland.
I guess we should do all of preparation in fill_super().
> + remove_inode_hash(inode);
> + fat_attach(inode, i_pos);
> + insert_inode_hash(inode);
> + brelse(bh);
Root inode should never change the position, so this shouldn't be
needed.
Thanks.
--
OGAWA Hirofumi <[email protected]>
Hello and thanks for your comments!
On Fri, 18 Sep 2009 20:33 +0900, "OGAWA Hirofumi"
<[email protected]> wrote:
> Jorg Schummer <[email protected]> writes:
>
> > Standard FAT implementations cannot store any of the FAT root directory's
> > timestamps. This commit adds the mount option 'rootts', which allows saving
> > the FAT root directory timestamps as the timestamps of the FAT volume label
> > directory entry. At least Mac OS X is known to support the same mechanism
> > and interoperate with this commit.
> >
> > When mounting, the following values can be specified for the 'rootts' mount
> > option:
> >
...
> >
> > "rootts=save" tries to load and save the root directory's timestamps.
> > The mtime and atime are corrected based on root
> > directory entries' ctime. If the root directory was
> > accessed but no volume label entry exists, the label
> > "NO NAME" is created.
>
> Um..., I'm still not sure though. rootts=save may not be needed for
> this, because it seems a bit complex, and it can do on userland...
It's true, that is quite of a hack after all. I just thought I'll try to
add the non-plus-ultra-feature on top of what Mac OS can do already.
But you're right, I'll get rid of the label creation. (And I think I
should get rid of the time stamp correction as well. If there is no
timestamp to be loaded, then 1970/1/1 should suffice. In case anyone
thinks that the timestamp 'correction' is anyhow useful, let me know...)
>
> And some quick review of implement..
>
> > + if (inode->i_ino == MSDOS_ROOT_INO) {
>
> In this path, we don't have inode->i_mutex, so to look directry up is
> wrong. I think adding label may move to userland.
>
> I guess we should do all of preparation in fill_super().
True. This code is only needed for the time stamp creation, so it'll go
in any case.
>
> > + remove_inode_hash(inode);
> > + fat_attach(inode, i_pos);
> > + insert_inode_hash(inode);
> > + brelse(bh);
>
> Root inode should never change the position, so this shouldn't be
> needed.
Like above, this will be removed.
If 'preserve' (i.e. saving and loading the timestamp only IF a label is
present) is the default, I'll remove the 'rootts=preserve' option.
However, should there still be an option to switch this feature off
completely ('rootts=ignore')?
Thanks very much for your comments, the next version will come soon!
J?rg
[email protected] writes:
> If 'preserve' (i.e. saving and loading the timestamp only IF a label is
> present) is the default, I'll remove the 'rootts=preserve' option.
> However, should there still be an option to switch this feature off
> completely ('rootts=ignore')?
I think it should be boolean (I.e. "rootts" as "rootts=preserve", and no
option as "rootts=ignore").
Thanks.
--
OGAWA Hirofumi <[email protected]>