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| author | Jan Kara <jack@suse.cz> | 2016-05-12 18:29:19 +0200 |
|---|---|---|
| committer | Ross Zwisler <ross.zwisler@linux.intel.com> | 2016-05-19 15:27:49 -0600 |
| commit | bc2466e4257369d0ebee2b6265070d323343fa72 (patch) | |
| tree | dc3c050e1b7bde8f0c93b1eb0764750f10331fed /include/linux/dax.h | |
| parent | ac401cc782429cc8560ce4840b1405d603740917 (diff) | |
| download | linux-stable-bc2466e4257369d0ebee2b6265070d323343fa72.tar.gz linux-stable-bc2466e4257369d0ebee2b6265070d323343fa72.tar.bz2 linux-stable-bc2466e4257369d0ebee2b6265070d323343fa72.zip | |
dax: Use radix tree entry lock to protect cow faults
When doing cow faults, we cannot directly fill in PTE as we do for other
faults as we rely on generic code to do proper accounting of the cowed page.
We also have no page to lock to protect against races with truncate as
other faults have and we need the protection to extend until the moment
generic code inserts cowed page into PTE thus at that point we have no
protection of fs-specific i_mmap_sem. So far we relied on using
i_mmap_lock for the protection however that is completely special to cow
faults. To make fault locking more uniform use DAX entry lock instead.
Reviewed-by: Ross Zwisler <ross.zwisler@linux.intel.com>
Signed-off-by: Jan Kara <jack@suse.cz>
Signed-off-by: Ross Zwisler <ross.zwisler@linux.intel.com>
Diffstat (limited to 'include/linux/dax.h')
| -rw-r--r-- | include/linux/dax.h | 7 |
1 files changed, 7 insertions, 0 deletions
diff --git a/include/linux/dax.h b/include/linux/dax.h index 756625c6d0dd..7bf12277c006 100644 --- a/include/linux/dax.h +++ b/include/linux/dax.h @@ -21,6 +21,7 @@ void dax_wake_mapping_entry_waiter(struct address_space *mapping, #ifdef CONFIG_FS_DAX struct page *read_dax_sector(struct block_device *bdev, sector_t n); +void dax_unlock_mapping_entry(struct address_space *mapping, pgoff_t index); int __dax_zero_page_range(struct block_device *bdev, sector_t sector, unsigned int offset, unsigned int length); #else @@ -29,6 +30,12 @@ static inline struct page *read_dax_sector(struct block_device *bdev, { return ERR_PTR(-ENXIO); } +/* Shouldn't ever be called when dax is disabled. */ +static inline void dax_unlock_mapping_entry(struct address_space *mapping, + pgoff_t index) +{ + BUG(); +} static inline int __dax_zero_page_range(struct block_device *bdev, sector_t sector, unsigned int offset, unsigned int length) { |