Relax the requirements on the writeback_mapping a_op.
This function is passed the number of pages which it should write. The
current fs-writeback.c code will get confused if the address_space
writes back more pages than it was asked to.
With this change the address_space may write more pages than required
if that is convenient. Extent-based fileystems may wish to do this.
=====================================
--- 2.5.18/fs/fs-writeback.c~relax-nr-to_write Sat May 25 23:26:46 2002
+++ 2.5.18-akpm/fs/fs-writeback.c Sun May 26 00:50:19 2002
@@ -257,7 +257,7 @@ static void sync_sb_inodes(struct super_
if (current_is_pdflush())
writeback_release(bdi);
- if (nr_to_write && *nr_to_write == 0)
+ if (nr_to_write && *nr_to_write <= 0)
break;
}
out:
@@ -301,7 +301,7 @@ void writeback_unlocked_inodes(int *nr_t
older_than_this);
spin_lock(&sb_lock);
}
- if (nr_to_write && *nr_to_write == 0)
+ if (nr_to_write && *nr_to_write <= 0)
break;
}
spin_unlock(&sb_lock);
--- 2.5.18/Documentation/filesystems/Locking~relax-nr-to_write Sat May 25 23:26:46 2002
+++ 2.5.18-akpm/Documentation/filesystems/Locking Sun May 26 00:50:22 2002
@@ -179,11 +179,12 @@ existing instances of this method ->sync
well-defined...
->writeback_mapping() is used for periodic writeback and for
-systemcall-initiated sync operations. The address_space should start
-I/O against at least *nr_to_write pages. *nr_to_write must be decremented
-for each page which is written. *nr_to_write must not go negative (this
-will be relaxed later). If nr_to_write is NULL, all dirty pages must
-be written.
+systemcall-initiated sync operations. The address_space should start
+I/O against at least *nr_to_write pages. *nr_to_write must be
+decremented for each page which is written. The address_space
+implementation may write more (or less) pages than *nr_to_write asks
+for, but it should try to be reasonably close. If nr_to_write is NULL,
+all dirty pages must be written.
->vm_writeback() is called from the VM. The address_space should
start I/O against at least *nr_to_write pages, including the passed page. As
-
-
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This archive was generated by hypermail 2b29 : Fri May 31 2002 - 22:00:18 EST