From: NeilBrown Date: Sun, 8 Jan 2006 09:02:39 +0000 (-0800) Subject: [PATCH] Fix some problems with truncate and mtime semantics. X-Git-Tag: v2.6.16-rc1~778 X-Git-Url: https://err.no/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=4a30131e7dbb17e5fec6958bfac9da9aff1fa29b;p=linux-2.6 [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 Cc: Christoph Hellwig Cc: Trond Myklebust Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds --- diff --git a/fs/attr.c b/fs/attr.c index 67bcd9b14e..b34732506f 100644 --- a/fs/attr.c +++ b/fs/attr.c @@ -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, struct iattr * attr) 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 e9650cd22a..2075b674d8 100644 --- a/fs/exec.c +++ b/fs/exec.c @@ -1505,7 +1505,7 @@ int do_coredump(long signr, int exit_code, struct pt_regs * regs) 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 6dbbd42d8b..300eae088d 100644 --- a/fs/namei.c +++ b/fs/namei.c @@ -1491,7 +1491,7 @@ int may_open(struct nameidata *nd, int acc_mode, int flag) 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 f53a5b9ffb..94968cb3af 100644 --- a/fs/open.c +++ b/fs/open.c @@ -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, loff_t length, struct file *filp) 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 char __user * path, loff_t length) 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(unsigned int fd, loff_t length, int small) 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 ef29500b5d..74c01aabd4 100644 --- a/include/linux/fs.h +++ b/include/linux/fs.h @@ -1344,7 +1344,8 @@ static inline int break_lease(struct inode *inode, unsigned int mode) /* 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);