diff options
author | Jan Harkes <jaharkes@cs.cmu.edu> | 2007-07-21 13:37:26 +0200 |
---|---|---|
committer | Linus Torvalds <torvalds@woody.linux-foundation.org> | 2007-07-22 02:49:14 +0200 |
commit | d3fec424b23c47686efcf3f2004c3f1c1cee4d9c (patch) | |
tree | ffad3cf369d35e85fca9a340347eea09caa53ff3 | |
parent | nommu: vmalloc_32_user()/vm_insert_page() and symbol exports. (diff) | |
download | linux-d3fec424b23c47686efcf3f2004c3f1c1cee4d9c.tar.xz linux-d3fec424b23c47686efcf3f2004c3f1c1cee4d9c.zip |
coda: remove CODA_STORE/CODA_RELEASE upcalls
This is an variation on the patch sent by Christoph Hellwig which kills
file_count abuse by the Coda kernel module by moving the coda_flush
functionality into coda_release. However part of reason we were using the
coda_flush callback was to allow Coda to pass errors that occur during
writeback from the userspace cache manager back to close().
As Al Viro explained on linux-fsdevel, it is impossible to guarantee that
such errors can in fact be returned back to the caller. There are many
cases where the last reference to a file is not released by the close
system call and it is also impossible to pick some close as a 'last-close'
and delay it until all other references have been destroyed.
The CODA_STORE/CODA_RELEASE upcall combination is clearly a broken design,
and it is better to remove it completely.
Signed-off-by: Jan Harkes <jaharkes@cs.cmu.edu>
Cc: Christoph Hellwig <hch@lst.de>
Cc: Al Viro <viro@ftp.linux.org.uk>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
-rw-r--r-- | fs/coda/dir.c | 1 | ||||
-rw-r--r-- | fs/coda/file.c | 65 | ||||
-rw-r--r-- | fs/coda/upcall.c | 49 | ||||
-rw-r--r-- | include/linux/coda_linux.h | 1 | ||||
-rw-r--r-- | include/linux/coda_psdev.h | 3 |
5 files changed, 7 insertions, 112 deletions
diff --git a/fs/coda/dir.c b/fs/coda/dir.c index 8e61236abf4a..f89ff083079b 100644 --- a/fs/coda/dir.c +++ b/fs/coda/dir.c @@ -86,7 +86,6 @@ const struct file_operations coda_dir_operations = { .read = generic_read_dir, .readdir = coda_readdir, .open = coda_open, - .flush = coda_flush, .release = coda_release, .fsync = coda_fsync, }; diff --git a/fs/coda/file.c b/fs/coda/file.c index 7594962604c2..29137ff3ca67 100644 --- a/fs/coda/file.c +++ b/fs/coda/file.c @@ -25,10 +25,6 @@ #include "coda_int.h" -/* if CODA_STORE fails with EOPNOTSUPP, venus clearly doesn't support - * CODA_STORE/CODA_RELEASE and we fall back on using the CODA_CLOSE upcall */ -static int use_coda_close; - static ssize_t coda_file_read(struct file *coda_file, char __user *buf, size_t count, loff_t *ppos) { @@ -163,47 +159,6 @@ int coda_open(struct inode *coda_inode, struct file *coda_file) return 0; } -int coda_flush(struct file *coda_file, fl_owner_t id) -{ - unsigned short flags = coda_file->f_flags & ~O_EXCL; - unsigned short coda_flags = coda_flags_to_cflags(flags); - struct coda_file_info *cfi; - struct inode *coda_inode; - int err = 0, fcnt; - - lock_kernel(); - - /* last close semantics */ - fcnt = file_count(coda_file); - if (fcnt > 1) - goto out; - - /* No need to make an upcall when we have not made any modifications - * to the file */ - if ((coda_file->f_flags & O_ACCMODE) == O_RDONLY) - goto out; - - if (use_coda_close) - goto out; - - cfi = CODA_FTOC(coda_file); - BUG_ON(!cfi || cfi->cfi_magic != CODA_MAGIC); - - coda_inode = coda_file->f_path.dentry->d_inode; - - err = venus_store(coda_inode->i_sb, coda_i2f(coda_inode), coda_flags, - coda_file->f_uid); - - if (err == -EOPNOTSUPP) { - use_coda_close = 1; - err = 0; - } - -out: - unlock_kernel(); - return err; -} - int coda_release(struct inode *coda_inode, struct file *coda_file) { unsigned short flags = (coda_file->f_flags) & (~O_EXCL); @@ -215,21 +170,11 @@ int coda_release(struct inode *coda_inode, struct file *coda_file) lock_kernel(); - if (!use_coda_close) { - err = venus_release(coda_inode->i_sb, coda_i2f(coda_inode), - coda_flags); - if (err == -EOPNOTSUPP) { - use_coda_close = 1; - err = 0; - } - } - cfi = CODA_FTOC(coda_file); BUG_ON(!cfi || cfi->cfi_magic != CODA_MAGIC); - if (use_coda_close) - err = venus_close(coda_inode->i_sb, coda_i2f(coda_inode), - coda_flags, coda_file->f_uid); + err = venus_close(coda_inode->i_sb, coda_i2f(coda_inode), + coda_flags, coda_file->f_uid); host_inode = cfi->cfi_container->f_path.dentry->d_inode; cii = ITOC(coda_inode); @@ -246,7 +191,10 @@ int coda_release(struct inode *coda_inode, struct file *coda_file) coda_file->private_data = NULL; unlock_kernel(); - return err; + + /* VFS fput ignores the return value from file_operations->release, so + * there is no use returning an error here */ + return 0; } int coda_fsync(struct file *coda_file, struct dentry *coda_dentry, int datasync) @@ -288,7 +236,6 @@ const struct file_operations coda_file_operations = { .write = coda_file_write, .mmap = coda_file_mmap, .open = coda_open, - .flush = coda_flush, .release = coda_release, .fsync = coda_fsync, .splice_read = coda_file_splice_read, diff --git a/fs/coda/upcall.c b/fs/coda/upcall.c index cd561d2e90b0..cdb4c07a7870 100644 --- a/fs/coda/upcall.c +++ b/fs/coda/upcall.c @@ -160,55 +160,8 @@ int venus_lookup(struct super_block *sb, struct CodaFid *fid, return error; } -int venus_store(struct super_block *sb, struct CodaFid *fid, int flags, - vuid_t uid) -{ - union inputArgs *inp; - union outputArgs *outp; - int insize, outsize, error; -#ifdef CONFIG_CODA_FS_OLD_API - struct coda_cred cred = { 0, }; - cred.cr_fsuid = uid; -#endif - - insize = SIZE(store); - UPARG(CODA_STORE); - -#ifdef CONFIG_CODA_FS_OLD_API - memcpy(&(inp->ih.cred), &cred, sizeof(cred)); -#else - inp->ih.uid = uid; -#endif - - inp->coda_store.VFid = *fid; - inp->coda_store.flags = flags; - - error = coda_upcall(coda_vcp(sb), insize, &outsize, inp); - - CODA_FREE(inp, insize); - return error; -} - -int venus_release(struct super_block *sb, struct CodaFid *fid, int flags) -{ - union inputArgs *inp; - union outputArgs *outp; - int insize, outsize, error; - - insize = SIZE(release); - UPARG(CODA_RELEASE); - - inp->coda_release.VFid = *fid; - inp->coda_release.flags = flags; - - error = coda_upcall(coda_vcp(sb), insize, &outsize, inp); - - CODA_FREE(inp, insize); - return error; -} - int venus_close(struct super_block *sb, struct CodaFid *fid, int flags, - vuid_t uid) + vuid_t uid) { union inputArgs *inp; union outputArgs *outp; diff --git a/include/linux/coda_linux.h b/include/linux/coda_linux.h index c4079b403e9e..1c47a34aa794 100644 --- a/include/linux/coda_linux.h +++ b/include/linux/coda_linux.h @@ -36,7 +36,6 @@ extern const struct file_operations coda_ioctl_operations; /* operations shared over more than one file */ int coda_open(struct inode *i, struct file *f); -int coda_flush(struct file *f, fl_owner_t id); int coda_release(struct inode *i, struct file *f); int coda_permission(struct inode *inode, int mask, struct nameidata *nd); int coda_revalidate_inode(struct dentry *); diff --git a/include/linux/coda_psdev.h b/include/linux/coda_psdev.h index aa8f454b3b77..07ae8f846055 100644 --- a/include/linux/coda_psdev.h +++ b/include/linux/coda_psdev.h @@ -33,9 +33,6 @@ int venus_setattr(struct super_block *, struct CodaFid *, struct coda_vattr *); int venus_lookup(struct super_block *sb, struct CodaFid *fid, const char *name, int length, int *type, struct CodaFid *resfid); -int venus_store(struct super_block *sb, struct CodaFid *fid, int flags, - vuid_t uid); -int venus_release(struct super_block *sb, struct CodaFid *fid, int flags); int venus_close(struct super_block *sb, struct CodaFid *fid, int flags, vuid_t uid); int venus_open(struct super_block *sb, struct CodaFid *fid, int flags, |