From 8f7d89f36829b9061a14f9040cda1372f264c4fe Mon Sep 17 00:00:00 2001 From: Jan Kara Date: Tue, 4 Jun 2013 12:35:11 -0400 Subject: jbd2: transaction reservation support In some cases we cannot start a transaction because of locking constraints and passing started transaction into those places is not handy either because we could block transaction commit for too long. Transaction reservation is designed to solve these issues. It reserves a handle with given number of credits in the journal and the handle can be later attached to the running transaction without blocking on commit or checkpointing. Reserved handles do not block transaction commit in any way, they only reduce maximum size of the running transaction (because we have to always be prepared to accomodate request for attaching reserved handle). Signed-off-by: Jan Kara Signed-off-by: "Theodore Ts'o" --- fs/ext4/ext4_jbd2.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) (limited to 'fs/ext4/ext4_jbd2.c') diff --git a/fs/ext4/ext4_jbd2.c b/fs/ext4/ext4_jbd2.c index 451eb4045330..bd25e782ec6b 100644 --- a/fs/ext4/ext4_jbd2.c +++ b/fs/ext4/ext4_jbd2.c @@ -62,7 +62,7 @@ handle_t *__ext4_journal_start_sb(struct super_block *sb, unsigned int line, ext4_abort(sb, "Detected aborted journal"); return ERR_PTR(-EROFS); } - return jbd2__journal_start(journal, nblocks, GFP_NOFS, type, line); + return jbd2__journal_start(journal, nblocks, 0, GFP_NOFS, type, line); } int __ext4_journal_stop(const char *where, unsigned int line, handle_t *handle) -- cgit v1.2.3 From 5fe2fe895a9a6b857e2f3a7fc5b8f080b03fd55f Mon Sep 17 00:00:00 2001 From: Jan Kara Date: Tue, 4 Jun 2013 12:37:50 -0400 Subject: ext4: provide wrappers for transaction reservation calls Reviewed-by: Zheng Liu Signed-off-by: Jan Kara Signed-off-by: "Theodore Ts'o" --- fs/ext4/ext4_jbd2.c | 58 +++++++++++++++++++++++++++++++++++++++++++---------- 1 file changed, 47 insertions(+), 11 deletions(-) (limited to 'fs/ext4/ext4_jbd2.c') diff --git a/fs/ext4/ext4_jbd2.c b/fs/ext4/ext4_jbd2.c index bd25e782ec6b..72a3600aedbd 100644 --- a/fs/ext4/ext4_jbd2.c +++ b/fs/ext4/ext4_jbd2.c @@ -38,31 +38,43 @@ static void ext4_put_nojournal(handle_t *handle) /* * Wrappers for jbd2_journal_start/end. */ -handle_t *__ext4_journal_start_sb(struct super_block *sb, unsigned int line, - int type, int nblocks) +static int ext4_journal_check_start(struct super_block *sb) { journal_t *journal; might_sleep(); - - trace_ext4_journal_start(sb, nblocks, _RET_IP_); if (sb->s_flags & MS_RDONLY) - return ERR_PTR(-EROFS); - + return -EROFS; WARN_ON(sb->s_writers.frozen == SB_FREEZE_COMPLETE); journal = EXT4_SB(sb)->s_journal; - if (!journal) - return ext4_get_nojournal(); /* * Special case here: if the journal has aborted behind our * backs (eg. EIO in the commit thread), then we still need to * take the FS itself readonly cleanly. */ - if (is_journal_aborted(journal)) { + if (journal && is_journal_aborted(journal)) { ext4_abort(sb, "Detected aborted journal"); - return ERR_PTR(-EROFS); + return -EROFS; } - return jbd2__journal_start(journal, nblocks, 0, GFP_NOFS, type, line); + return 0; +} + +handle_t *__ext4_journal_start_sb(struct super_block *sb, unsigned int line, + int type, int blocks, int rsv_blocks) +{ + journal_t *journal; + int err; + + trace_ext4_journal_start(sb, blocks, rsv_blocks, _RET_IP_); + err = ext4_journal_check_start(sb); + if (err < 0) + return ERR_PTR(err); + + journal = EXT4_SB(sb)->s_journal; + if (!journal) + return ext4_get_nojournal(); + return jbd2__journal_start(journal, blocks, rsv_blocks, GFP_NOFS, + type, line); } int __ext4_journal_stop(const char *where, unsigned int line, handle_t *handle) @@ -86,6 +98,30 @@ int __ext4_journal_stop(const char *where, unsigned int line, handle_t *handle) return err; } +handle_t *__ext4_journal_start_reserved(handle_t *handle, unsigned int line, + int type) +{ + struct super_block *sb; + int err; + + if (!ext4_handle_valid(handle)) + return ext4_get_nojournal(); + + sb = handle->h_journal->j_private; + trace_ext4_journal_start_reserved(sb, handle->h_buffer_credits, + _RET_IP_); + err = ext4_journal_check_start(sb); + if (err < 0) { + jbd2_journal_free_reserved(handle); + return ERR_PTR(err); + } + + err = jbd2_journal_start_reserved(handle, type, line); + if (err < 0) + return ERR_PTR(err); + return handle; +} + void ext4_journal_abort_handle(const char *caller, unsigned int line, const char *err_fn, struct buffer_head *bh, handle_t *handle, int err) -- cgit v1.2.3