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@xxxxxxxxxx>
Cc: Christoph Hellwig <hch@xxxxxx>
Cc: Al Viro <viro@xxxxxxxxxxxxxxxx>
---
fs/coda/dir.c | 1 -
fs/coda/file.c | 65 ++++---------------------------------------
fs/coda/upcall.c | 49 +--------------------------------
include/linux/coda_linux.h | 1 -
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 8e61236..f89ff08 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 7594962..29137ff 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 cd561d2..cdb4c07 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 c4079b4..1c47a34 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 aa8f454..07ae8f8 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,
--
1.5.2.1
-
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