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author | Linus Torvalds <torvalds@linux-foundation.org> | 2011-10-25 15:42:01 +0200 |
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committer | Linus Torvalds <torvalds@linux-foundation.org> | 2011-10-25 15:42:01 +0200 |
commit | 1442d1678ca7e53574fd403ba7bee6f4125d920c (patch) | |
tree | fd053a849158d2c5b8345ced8982108825b85736 /fs/locks.c | |
parent | Merge branch 'pm-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/... (diff) | |
parent | nfs41: implement DESTROY_CLIENTID operation (diff) | |
download | linux-1442d1678ca7e53574fd403ba7bee6f4125d920c.tar.xz linux-1442d1678ca7e53574fd403ba7bee6f4125d920c.zip |
Merge branch 'for-3.2' of git://linux-nfs.org/~bfields/linux
* 'for-3.2' of git://linux-nfs.org/~bfields/linux: (103 commits)
nfs41: implement DESTROY_CLIENTID operation
nfsd4: typo logical vs bitwise negate for want_mask
nfsd4: allow NFS4_SHARE_SIGNAL_DELEG_WHEN_RESRC_AVAIL | NFS4_SHARE_PUSH_DELEG_WHEN_UNCONTENDED
nfsd4: seq->status_flags may be used unitialized
nfsd41: use SEQ4_STATUS_BACKCHANNEL_FAULT when cb_sequence is invalid
nfsd4: implement new 4.1 open reclaim types
nfsd4: remove unneeded CLAIM_DELEGATE_CUR workaround
nfsd4: warn on open failure after create
nfsd4: preallocate open stateid in process_open1()
nfsd4: do idr preallocation with stateid allocation
nfsd4: preallocate nfs4_file in process_open1()
nfsd4: clean up open owners on OPEN failure
nfsd4: simplify process_open1 logic
nfsd4: make is_open_owner boolean
nfsd4: centralize renew_client() calls
nfsd4: typo logical vs bitwise negate
nfs: fix bug about IPv6 address scope checking
nfsd4: more robust ignoring of WANT bits in OPEN
nfsd4: move name-length checks to xdr
nfsd4: move access/deny validity checks to xdr code
...
Diffstat (limited to 'fs/locks.c')
-rw-r--r-- | fs/locks.c | 223 |
1 files changed, 140 insertions, 83 deletions
diff --git a/fs/locks.c b/fs/locks.c index 96b33989147d..3b0d05dcd7c1 100644 --- a/fs/locks.c +++ b/fs/locks.c @@ -133,6 +133,20 @@ #define IS_FLOCK(fl) (fl->fl_flags & FL_FLOCK) #define IS_LEASE(fl) (fl->fl_flags & FL_LEASE) +static bool lease_breaking(struct file_lock *fl) +{ + return fl->fl_flags & (FL_UNLOCK_PENDING | FL_DOWNGRADE_PENDING); +} + +static int target_leasetype(struct file_lock *fl) +{ + if (fl->fl_flags & FL_UNLOCK_PENDING) + return F_UNLCK; + if (fl->fl_flags & FL_DOWNGRADE_PENDING) + return F_RDLCK; + return fl->fl_type; +} + int leases_enable = 1; int lease_break_time = 45; @@ -1119,6 +1133,17 @@ int locks_mandatory_area(int read_write, struct inode *inode, EXPORT_SYMBOL(locks_mandatory_area); +static void lease_clear_pending(struct file_lock *fl, int arg) +{ + switch (arg) { + case F_UNLCK: + fl->fl_flags &= ~FL_UNLOCK_PENDING; + /* fall through: */ + case F_RDLCK: + fl->fl_flags &= ~FL_DOWNGRADE_PENDING; + } +} + /* We already had a lease on this file; just change its type */ int lease_modify(struct file_lock **before, int arg) { @@ -1127,6 +1152,7 @@ int lease_modify(struct file_lock **before, int arg) if (error) return error; + lease_clear_pending(fl, arg); locks_wake_up_blocks(fl); if (arg == F_UNLCK) locks_delete_lock(before); @@ -1135,19 +1161,25 @@ int lease_modify(struct file_lock **before, int arg) EXPORT_SYMBOL(lease_modify); +static bool past_time(unsigned long then) +{ + if (!then) + /* 0 is a special value meaning "this never expires": */ + return false; + return time_after(jiffies, then); +} + static void time_out_leases(struct inode *inode) { struct file_lock **before; struct file_lock *fl; before = &inode->i_flock; - while ((fl = *before) && IS_LEASE(fl) && (fl->fl_type & F_INPROGRESS)) { - if ((fl->fl_break_time == 0) - || time_before(jiffies, fl->fl_break_time)) { - before = &fl->fl_next; - continue; - } - lease_modify(before, fl->fl_type & ~F_INPROGRESS); + while ((fl = *before) && IS_LEASE(fl) && lease_breaking(fl)) { + if (past_time(fl->fl_downgrade_time)) + lease_modify(before, F_RDLCK); + if (past_time(fl->fl_break_time)) + lease_modify(before, F_UNLCK); if (fl == *before) /* lease_modify may have freed fl */ before = &fl->fl_next; } @@ -1165,7 +1197,7 @@ static void time_out_leases(struct inode *inode) */ int __break_lease(struct inode *inode, unsigned int mode) { - int error = 0, future; + int error = 0; struct file_lock *new_fl, *flock; struct file_lock *fl; unsigned long break_time; @@ -1182,24 +1214,13 @@ int __break_lease(struct inode *inode, unsigned int mode) if ((flock == NULL) || !IS_LEASE(flock)) goto out; + if (!locks_conflict(flock, new_fl)) + goto out; + for (fl = flock; fl && IS_LEASE(fl); fl = fl->fl_next) if (fl->fl_owner == current->files) i_have_this_lease = 1; - if (want_write) { - /* If we want write access, we have to revoke any lease. */ - future = F_UNLCK | F_INPROGRESS; - } else if (flock->fl_type & F_INPROGRESS) { - /* If the lease is already being broken, we just leave it */ - future = flock->fl_type; - } else if (flock->fl_type & F_WRLCK) { - /* Downgrade the exclusive lease to a read-only lease. */ - future = F_RDLCK | F_INPROGRESS; - } else { - /* the existing lease was read-only, so we can read too. */ - goto out; - } - if (IS_ERR(new_fl) && !i_have_this_lease && ((mode & O_NONBLOCK) == 0)) { error = PTR_ERR(new_fl); @@ -1214,12 +1235,18 @@ int __break_lease(struct inode *inode, unsigned int mode) } for (fl = flock; fl && IS_LEASE(fl); fl = fl->fl_next) { - if (fl->fl_type != future) { - fl->fl_type = future; + if (want_write) { + if (fl->fl_flags & FL_UNLOCK_PENDING) + continue; + fl->fl_flags |= FL_UNLOCK_PENDING; fl->fl_break_time = break_time; - /* lease must have lmops break callback */ - fl->fl_lmops->lm_break(fl); + } else { + if (lease_breaking(flock)) + continue; + fl->fl_flags |= FL_DOWNGRADE_PENDING; + fl->fl_downgrade_time = break_time; } + fl->fl_lmops->lm_break(fl); } if (i_have_this_lease || (mode & O_NONBLOCK)) { @@ -1243,10 +1270,13 @@ restart: if (error >= 0) { if (error == 0) time_out_leases(inode); - /* Wait for the next lease that has not been broken yet */ + /* + * Wait for the next conflicting lease that has not been + * broken yet + */ for (flock = inode->i_flock; flock && IS_LEASE(flock); flock = flock->fl_next) { - if (flock->fl_type & F_INPROGRESS) + if (locks_conflict(new_fl, flock)) goto restart; } error = 0; @@ -1314,7 +1344,7 @@ int fcntl_getlease(struct file *filp) for (fl = filp->f_path.dentry->d_inode->i_flock; fl && IS_LEASE(fl); fl = fl->fl_next) { if (fl->fl_file == filp) { - type = fl->fl_type & ~F_INPROGRESS; + type = target_leasetype(fl); break; } } @@ -1322,50 +1352,23 @@ int fcntl_getlease(struct file *filp) return type; } -/** - * generic_setlease - sets a lease on an open file - * @filp: file pointer - * @arg: type of lease to obtain - * @flp: input - file_lock to use, output - file_lock inserted - * - * The (input) flp->fl_lmops->lm_break function is required - * by break_lease(). - * - * Called with file_lock_lock held. - */ -int generic_setlease(struct file *filp, long arg, struct file_lock **flp) +int generic_add_lease(struct file *filp, long arg, struct file_lock **flp) { struct file_lock *fl, **before, **my_before = NULL, *lease; struct dentry *dentry = filp->f_path.dentry; struct inode *inode = dentry->d_inode; - int error, rdlease_count = 0, wrlease_count = 0; + int error; lease = *flp; - error = -EACCES; - if ((current_fsuid() != inode->i_uid) && !capable(CAP_LEASE)) - goto out; - error = -EINVAL; - if (!S_ISREG(inode->i_mode)) + error = -EAGAIN; + if ((arg == F_RDLCK) && (atomic_read(&inode->i_writecount) > 0)) goto out; - error = security_file_lock(filp, arg); - if (error) + if ((arg == F_WRLCK) + && ((dentry->d_count > 1) + || (atomic_read(&inode->i_count) > 1))) goto out; - time_out_leases(inode); - - BUG_ON(!(*flp)->fl_lmops->lm_break); - - if (arg != F_UNLCK) { - error = -EAGAIN; - if ((arg == F_RDLCK) && (atomic_read(&inode->i_writecount) > 0)) - goto out; - if ((arg == F_WRLCK) - && ((dentry->d_count > 1) - || (atomic_read(&inode->i_count) > 1))) - goto out; - } - /* * At this point, we know that if there is an exclusive * lease on this file, then we hold it on this filp @@ -1374,27 +1377,28 @@ int generic_setlease(struct file *filp, long arg, struct file_lock **flp) * then the file is not open by anyone (including us) * except for this filp. */ + error = -EAGAIN; 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) { my_before = before; - else if (fl->fl_type == (F_INPROGRESS | F_UNLCK)) - /* - * Someone is in the process of opening this - * file for writing so we may not take an - * exclusive lease on it. - */ - wrlease_count++; - else - rdlease_count++; + continue; + } + /* + * No exclusive leases if someone else has a lease on + * this file: + */ + if (arg == F_WRLCK) + goto out; + /* + * Modifying our existing lease is OK, but no getting a + * new lease if someone else is opening for write: + */ + if (fl->fl_flags & FL_UNLOCK_PENDING) + goto out; } - error = -EAGAIN; - if ((arg == F_RDLCK && (wrlease_count > 0)) || - (arg == F_WRLCK && ((rdlease_count + wrlease_count) > 0))) - goto out; - if (my_before != NULL) { error = lease->fl_lmops->lm_change(my_before, arg); if (!error) @@ -1402,9 +1406,6 @@ int generic_setlease(struct file *filp, long arg, struct file_lock **flp) goto out; } - if (arg == F_UNLCK) - goto out; - error = -EINVAL; if (!leases_enable) goto out; @@ -1415,6 +1416,62 @@ int generic_setlease(struct file *filp, long arg, struct file_lock **flp) out: return error; } + +int generic_delete_lease(struct file *filp, struct file_lock **flp) +{ + struct file_lock *fl, **before; + struct dentry *dentry = filp->f_path.dentry; + struct inode *inode = dentry->d_inode; + + for (before = &inode->i_flock; + ((fl = *before) != NULL) && IS_LEASE(fl); + before = &fl->fl_next) { + if (fl->fl_file != filp) + continue; + return (*flp)->fl_lmops->lm_change(before, F_UNLCK); + } + return -EAGAIN; +} + +/** + * generic_setlease - sets a lease on an open file + * @filp: file pointer + * @arg: type of lease to obtain + * @flp: input - file_lock to use, output - file_lock inserted + * + * The (input) flp->fl_lmops->lm_break function is required + * by break_lease(). + * + * Called with file_lock_lock held. + */ +int generic_setlease(struct file *filp, long arg, struct file_lock **flp) +{ + struct dentry *dentry = filp->f_path.dentry; + struct inode *inode = dentry->d_inode; + int error; + + if ((current_fsuid() != inode->i_uid) && !capable(CAP_LEASE)) + return -EACCES; + if (!S_ISREG(inode->i_mode)) + return -EINVAL; + error = security_file_lock(filp, arg); + if (error) + return error; + + time_out_leases(inode); + + BUG_ON(!(*flp)->fl_lmops->lm_break); + + switch (arg) { + case F_UNLCK: + return generic_delete_lease(filp, flp); + case F_RDLCK: + case F_WRLCK: + return generic_add_lease(filp, arg, flp); + default: + BUG(); + } +} EXPORT_SYMBOL(generic_setlease); static int __vfs_setlease(struct file *filp, long arg, struct file_lock **lease) @@ -2126,7 +2183,7 @@ static void lock_get_status(struct seq_file *f, struct file_lock *fl, } } else if (IS_LEASE(fl)) { seq_printf(f, "LEASE "); - if (fl->fl_type & F_INPROGRESS) + if (lease_breaking(fl)) seq_printf(f, "BREAKING "); else if (fl->fl_file) seq_printf(f, "ACTIVE "); @@ -2142,7 +2199,7 @@ static void lock_get_status(struct seq_file *f, struct file_lock *fl, : (fl->fl_type & LOCK_WRITE) ? "WRITE" : "NONE "); } else { seq_printf(f, "%s ", - (fl->fl_type & F_INPROGRESS) + (lease_breaking(fl)) ? (fl->fl_type & F_UNLCK) ? "UNLCK" : "READ " : (fl->fl_type & F_WRLCK) ? "WRITE" : "READ "); } |