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| author | Michael Haggerty <mhagger@alum.mit.edu> | 2015-05-11 12:35:25 +0200 |
|---|---|---|
| committer | Junio C Hamano <gitster@pobox.com> | 2015-05-14 14:51:08 -0700 |
| commit | 044b6a9efecf9941073b99ced4cb2881b18aee62 (patch) | |
| tree | 5cfbf39335b835c77d09d94250c2e4aaa8c2897a /lockfile.h | |
| parent | 1ea28e149403ba92f95205f324cc3119fb92df07 (diff) | |
| download | git-044b6a9efecf9941073b99ced4cb2881b18aee62.tar.gz | |
lockfile: allow file locking to be retried with a timeout
Currently, there is only one attempt to lock a file. If it fails, the
whole operation fails.
But it might sometimes be advantageous to try acquiring a file lock a
few times before giving up. So add a new function,
hold_lock_file_for_update_timeout(), that allows a timeout to be
specified. Make hold_lock_file_for_update() a thin wrapper around the
new function.
If timeout_ms is positive, then retry for at least that many
milliseconds to acquire the lock. On each failed attempt, use select()
to wait for a backoff time that increases quadratically (capped at 1
second) and has a random component to prevent two processes from
getting synchronized. If timeout_ms is negative, retry indefinitely.
In a moment we will switch to using the new function when locking
packed-refs.
Signed-off-by: Michael Haggerty <mhagger@alum.mit.edu>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
Diffstat (limited to 'lockfile.h')
| -rw-r--r-- | lockfile.h | 16 |
1 files changed, 14 insertions, 2 deletions
diff --git a/lockfile.h b/lockfile.h index cd2ec95d30..b4abc61c00 100644 --- a/lockfile.h +++ b/lockfile.h @@ -74,8 +74,20 @@ struct lock_file { extern void unable_to_lock_message(const char *path, int err, struct strbuf *buf); extern NORETURN void unable_to_lock_die(const char *path, int err); -extern int hold_lock_file_for_update(struct lock_file *, const char *path, int); -extern int hold_lock_file_for_append(struct lock_file *, const char *path, int); +extern int hold_lock_file_for_update_timeout( + struct lock_file *lk, const char *path, + int flags, long timeout_ms); + +static inline int hold_lock_file_for_update( + struct lock_file *lk, const char *path, + int flags) +{ + return hold_lock_file_for_update_timeout(lk, path, flags, 0); +} + +extern int hold_lock_file_for_append(struct lock_file *lk, const char *path, + int flags); + extern FILE *fdopen_lock_file(struct lock_file *, const char *mode); extern char *get_locked_file_path(struct lock_file *); extern int commit_lock_file_to(struct lock_file *, const char *path); |