Resubmitting this patch to fix truncate/mtime semantics.
It is against 2.6.14-mm2 and is probably suitable for 2.6.15, but can
be held over to 2.6.16 if you are feeling cautious.
NeilBrown
### Comments for Changeset
SUS requires that when truncating a file to the size that it currently
is:
truncate and ftruncate should NOT modify ctime or mtime
O_EXCL SHOULD modify ctime and mtime.
Currently mtime and ctime are always modified on most local
filesystems (side effect of ->truncate) or never modified (on NFS).
With this patch:
ATTR_CTIME|ATTR_MTIME are sent with ATTR_SIZE precisely when
an update of these times is required whether size changes or not
(via a new argument to do_truncate). This allows NFS to do
the right thing for O_EXCL.
inode_setattr nolonger forces ATTR_MTIME|ATTR_CTIME when the ATTR_SIZE
sets the size to it's current value. This allows local filesystems
to do the right thing for f?truncate.
Also, the logic in inode_setattr is changed a bit so there are two
return points. One returns the error from vmtruncate if it failed,
the other returns 0 (there can be no other failure).
Finally, if vmtruncate succeeds, and ATTR_SIZE is the only change
requested, we now fall-through and mark_inode_dirty. If a filesystem
did not have a ->truncate function, then vmtruncate will have changed
i_size, without marking the inode as 'dirty', and I think this is wrong.
Signed-off-by: Neil Brown <[email protected]>
### Diffstat output
./fs/attr.c | 22 +++++++---------------
./fs/exec.c | 2 +-
./fs/namei.c | 2 +-
./fs/open.c | 9 +++++----
./include/linux/fs.h | 3 ++-
5 files changed, 16 insertions(+), 22 deletions(-)
diff ./fs/attr.c~current~ ./fs/attr.c
--- ./fs/attr.c~current~ 2005-11-15 10:29:55.000000000 +1100
+++ ./fs/attr.c 2005-11-15 10:29:55.000000000 +1100
@@ -67,20 +67,12 @@ EXPORT_SYMBOL(inode_change_ok);
int inode_setattr(struct inode * inode, struct iattr * attr)
{
unsigned int ia_valid = attr->ia_valid;
- int error = 0;
- if (ia_valid & ATTR_SIZE) {
- if (attr->ia_size != i_size_read(inode)) {
- error = vmtruncate(inode, attr->ia_size);
- if (error || (ia_valid == ATTR_SIZE))
- goto out;
- } else {
- /*
- * We skipped the truncate but must still update
- * timestamps
- */
- ia_valid |= ATTR_MTIME|ATTR_CTIME;
- }
+ if (ia_valid & ATTR_SIZE &&
+ attr->ia_size != i_size_read(inode)) {
+ int error = vmtruncate(inode, attr->ia_size);
+ if (error)
+ return error;
}
if (ia_valid & ATTR_UID)
@@ -104,8 +96,8 @@ int inode_setattr(struct inode * inode,
inode->i_mode = mode;
}
mark_inode_dirty(inode);
-out:
- return error;
+
+ return 0;
}
EXPORT_SYMBOL(inode_setattr);
diff ./fs/exec.c~current~ ./fs/exec.c
--- ./fs/exec.c~current~ 2005-11-15 10:29:55.000000000 +1100
+++ ./fs/exec.c 2005-11-15 10:29:55.000000000 +1100
@@ -1516,7 +1516,7 @@ int do_coredump(long signr, int exit_cod
goto close_fail;
if (!file->f_op->write)
goto close_fail;
- if (do_truncate(file->f_dentry, 0, file) != 0)
+ if (do_truncate(file->f_dentry, 0, 0, file) != 0)
goto close_fail;
retval = binfmt->core_dump(signr, regs, file);
diff ./fs/namei.c~current~ ./fs/namei.c
--- ./fs/namei.c~current~ 2005-11-15 10:29:55.000000000 +1100
+++ ./fs/namei.c 2005-11-15 10:29:55.000000000 +1100
@@ -1491,7 +1491,7 @@ int may_open(struct nameidata *nd, int a
if (!error) {
DQUOT_INIT(inode);
- error = do_truncate(dentry, 0, NULL);
+ error = do_truncate(dentry, 0, ATTR_MTIME|ATTR_CTIME, NULL);
}
put_write_access(inode);
if (error)
diff ./fs/open.c~current~ ./fs/open.c
--- ./fs/open.c~current~ 2005-11-15 10:29:55.000000000 +1100
+++ ./fs/open.c 2005-11-15 10:29:55.000000000 +1100
@@ -194,7 +194,8 @@ out:
return error;
}
-int do_truncate(struct dentry *dentry, loff_t length, struct file *filp)
+int do_truncate(struct dentry *dentry, loff_t length, unsigned int time_attrs,
+ struct file *filp)
{
int err;
struct iattr newattrs;
@@ -204,7 +205,7 @@ int do_truncate(struct dentry *dentry, l
return -EINVAL;
newattrs.ia_size = length;
- newattrs.ia_valid = ATTR_SIZE | ATTR_CTIME;
+ newattrs.ia_valid = ATTR_SIZE | time_attrs;
if (filp) {
newattrs.ia_file = filp;
newattrs.ia_valid |= ATTR_FILE;
@@ -266,7 +267,7 @@ static inline long do_sys_truncate(const
error = locks_verify_truncate(inode, NULL, length);
if (!error) {
DQUOT_INIT(inode);
- error = do_truncate(nd.dentry, length, NULL);
+ error = do_truncate(nd.dentry, length, 0, NULL);
}
put_write_access(inode);
@@ -318,7 +319,7 @@ static inline long do_sys_ftruncate(unsi
error = locks_verify_truncate(inode, file, length);
if (!error)
- error = do_truncate(dentry, length, file);
+ error = do_truncate(dentry, length, 0, file);
out_putf:
fput(file);
out:
diff ./include/linux/fs.h~current~ ./include/linux/fs.h
--- ./include/linux/fs.h~current~ 2005-11-15 10:29:55.000000000 +1100
+++ ./include/linux/fs.h 2005-11-15 10:29:55.000000000 +1100
@@ -1340,7 +1340,8 @@ static inline int break_lease(struct ino
/* fs/open.c */
-extern int do_truncate(struct dentry *, loff_t start, struct file *filp);
+extern int do_truncate(struct dentry *, loff_t start, unsigned int time_attrs,
+ struct file *filp);
extern long do_sys_open(const char __user *filename, int flags, int mode);
extern struct file *filp_open(const char *, int, int);
extern struct file * dentry_open(struct dentry *, struct vfsmount *, int);
-
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