relax nr_to_write requirements
Subsystems (2)
PATCH 6/18 relax nr_to_write requirements
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.
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fs/fs-writeback.c renamed from fs/fs-writeback.c~relax-nr-to_write +2 -2
@@ -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);
Documentation/filesystems/Locking renamed from Documentation/filesystems/Locking~relax-nr-to_write +6 -5
@@ -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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