[PATCH] Fix some problems with truncate and mtime semantics.
SUS requires that when truncating a file to the size that it currently
is:
truncate and ftruncate should NOT modify ctime or mtime
O_TRUNC 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_TRUNC.
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 <neilb@suse.de>
Cc: Christoph Hellwig <hch@lst.de>
Cc: Trond Myklebust <trond.myklebust@fys.uio.no>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
diff --git a/fs/attr.c b/fs/attr.c
index 67bcd9b..b347325 100644
--- a/fs/attr.c
+++ b/fs/attr.c
@@ -67,20 +67,12 @@
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 @@
inode->i_mode = mode;
}
mark_inode_dirty(inode);
-out:
- return error;
+
+ return 0;
}
EXPORT_SYMBOL(inode_setattr);
diff --git a/fs/exec.c b/fs/exec.c
index e9650cd..2075b67 100644
--- a/fs/exec.c
+++ b/fs/exec.c
@@ -1505,7 +1505,7 @@
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 --git a/fs/namei.c b/fs/namei.c
index 6dbbd42..300eae0 100644
--- a/fs/namei.c
+++ b/fs/namei.c
@@ -1491,7 +1491,7 @@
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 --git a/fs/open.c b/fs/open.c
index f53a5b9..94968cb 100644
--- a/fs/open.c
+++ b/fs/open.c
@@ -194,7 +194,8 @@
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 @@
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 @@
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 @@
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 --git a/include/linux/fs.h b/include/linux/fs.h
index ef29500..74c01aa 100644
--- a/include/linux/fs.h
+++ b/include/linux/fs.h
@@ -1344,7 +1344,8 @@
/* 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);
