This (ab-)uses the file locking code to allow filesystems to recall
outstanding pNFS layouts on a file. This new lease type is similar but
not quite the same as FL_DELEG. A FL_LAYOUT lease can always be granted,
an a per-filesystem lock (XFS iolock for the initial implementation)
ensures not FL_LAYOUT leases granted when we would need to recall them.
Also included are changes that allow multiple outstanding read
leases of different types on the same file as long as they have a
differnt owner. This wasn't a problem until now as nfsd never set
FL_LEASE leases, and no one else used FL_DELEG leases, but given that
nfsd will also issues FL_LAYOUT leases we will have to handle it now.
Signed-off-by: Christoph Hellwig <hch@xxxxxx>
---
fs/locks.c | 28 +++++++++++++++++++---------
fs/nfsd/nfs4state.c | 2 +-
include/linux/fs.h | 16 ++++++++++++++++
3 files changed, 36 insertions(+), 10 deletions(-)
diff --git a/fs/locks.c b/fs/locks.c
index 735b8d3..6cf41f8 100644
--- a/fs/locks.c
+++ b/fs/locks.c
@@ -137,7 +137,7 @@
#define IS_POSIX(fl) (fl->fl_flags & FL_POSIX)
#define IS_FLOCK(fl) (fl->fl_flags & FL_FLOCK)
-#define IS_LEASE(fl) (fl->fl_flags & (FL_LEASE|FL_DELEG))
+#define IS_LEASE(fl) (fl->fl_flags & (FL_LEASE|FL_DELEG|FL_LAYOUT))
#define IS_OFDLCK(fl) (fl->fl_flags & FL_OFDLCK)
static bool lease_breaking(struct file_lock *fl)
@@ -1348,6 +1348,8 @@ static void time_out_leases(struct inode *inode, struct list_head *dispose)
static bool leases_conflict(struct file_lock *lease, struct file_lock *breaker)
{
+ if ((breaker->fl_flags & FL_LAYOUT) != (lease->fl_flags & FL_LAYOUT))
+ return false;
if ((breaker->fl_flags & FL_DELEG) && (lease->fl_flags & FL_LEASE))
return false;
return locks_conflict(breaker, lease);
@@ -1560,11 +1562,14 @@ int fcntl_getlease(struct file *filp)
* conflict with the lease we're trying to set.
*/
static int
-check_conflicting_open(const struct dentry *dentry, const long arg)
+check_conflicting_open(const struct dentry *dentry, const long arg, int flags)
{
int ret = 0;
struct inode *inode = dentry->d_inode;
+ if (flags & FL_LAYOUT)
+ return 0;
+
if ((arg == F_RDLCK) && (atomic_read(&inode->i_writecount) > 0))
return -EAGAIN;
@@ -1608,7 +1613,7 @@ generic_add_lease(struct file *filp, long arg, struct file_lock **flp, void **pr
spin_lock(&inode->i_lock);
time_out_leases(inode, &dispose);
- error = check_conflicting_open(dentry, arg);
+ error = check_conflicting_open(dentry, arg, lease->fl_flags);
if (error)
goto out;
@@ -1624,10 +1629,13 @@ generic_add_lease(struct file *filp, long arg, struct file_lock **flp, void **pr
for (before = &inode->i_flock;
((fl = *before) != NULL) && IS_LEASE(fl);
before = &fl->fl_next) {
- if (fl->fl_file == filp) {
+
+ if (fl->fl_file == filp &&
+ fl->fl_owner == lease->fl_owner) {
my_before = before;
continue;
}
+
/*
* No exclusive leases if someone else has a lease on
* this file:
@@ -1665,7 +1673,7 @@ generic_add_lease(struct file *filp, long arg, struct file_lock **flp, void **pr
* precedes these checks.
*/
smp_mb();
- error = check_conflicting_open(dentry, arg);
+ error = check_conflicting_open(dentry, arg, lease->fl_flags);
if (error)
goto out_unlink;
@@ -1685,7 +1693,7 @@ out_unlink:
goto out;
}
-static int generic_delete_lease(struct file *filp)
+static int generic_delete_lease(struct file *filp, void *priv)
{
int error = -EAGAIN;
struct file_lock *fl, **before;
@@ -1698,7 +1706,8 @@ static int generic_delete_lease(struct file *filp)
for (before = &inode->i_flock;
((fl = *before) != NULL) && IS_LEASE(fl);
before = &fl->fl_next) {
- if (fl->fl_file == filp)
+ if (fl->fl_file == filp &&
+ priv == fl->fl_owner)
break;
}
trace_generic_delete_lease(inode, fl);
@@ -1737,13 +1746,14 @@ int generic_setlease(struct file *filp, long arg, struct file_lock **flp,
switch (arg) {
case F_UNLCK:
- return generic_delete_lease(filp);
+ return generic_delete_lease(filp, *priv);
case F_RDLCK:
case F_WRLCK:
if (!(*flp)->fl_lmops->lm_break) {
WARN_ON_ONCE(1);
return -ENOLCK;
}
+
return generic_add_lease(filp, arg, flp, priv);
default:
return -EINVAL;
@@ -1816,7 +1826,7 @@ static int do_fcntl_add_lease(unsigned int fd, struct file *filp, long arg)
int fcntl_setlease(unsigned int fd, struct file *filp, long arg)
{
if (arg == F_UNLCK)
- return vfs_setlease(filp, F_UNLCK, NULL, NULL);
+ return vfs_setlease(filp, F_UNLCK, NULL, (void **)&filp);
return do_fcntl_add_lease(fd, filp, arg);
}
diff --git a/fs/nfsd/nfs4state.c b/fs/nfsd/nfs4state.c
index 277f8b8..2505b68 100644
--- a/fs/nfsd/nfs4state.c
+++ b/fs/nfsd/nfs4state.c
@@ -693,7 +693,7 @@ static void nfs4_put_deleg_lease(struct nfs4_file *fp)
spin_unlock(&fp->fi_lock);
if (filp) {
- vfs_setlease(filp, F_UNLCK, NULL, NULL);
+ vfs_setlease(filp, F_UNLCK, NULL, (void **)&fp);
fput(filp);
}
}
diff --git a/include/linux/fs.h b/include/linux/fs.h
index f90c028..204cf91 100644
--- a/include/linux/fs.h
+++ b/include/linux/fs.h
@@ -875,6 +875,7 @@ static inline struct file *get_file(struct file *f)
#define FL_DOWNGRADE_PENDING 256 /* Lease is being downgraded */
#define FL_UNLOCK_PENDING 512 /* Lease is being broken */
#define FL_OFDLCK 1024 /* lock is "owned" by struct file */
+#define FL_LAYOUT 2048 /* outstanding pNFS layout */
/*
* Special return value from posix_lock_file() and vfs_lock_file() for
@@ -2017,6 +2018,16 @@ static inline int break_deleg_wait(struct inode **delegated_inode)
return ret;
}
+static inline int break_layout(struct inode *inode, bool wait)
+{
+ smp_mb();
+ if (inode->i_flock)
+ return __break_lease(inode,
+ wait ? O_WRONLY : O_WRONLY | O_NONBLOCK,
+ FL_LAYOUT);
+ return 0;
+}
+
#else /* !CONFIG_FILE_LOCKING */
static inline int locks_mandatory_locked(struct file *file)
{
@@ -2072,6 +2083,11 @@ static inline int break_deleg_wait(struct inode **delegated_inode)
return 0;
}
+static inline int break_layout(struct inode *inode, bool wait)
+{
+ return 0;
+}
+
#endif /* CONFIG_FILE_LOCKING */
/* fs/open.c */
--
1.9.1
--
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