| Message ID | 1478034381-19037-9-git-send-email-jack@suse.cz (mailing list archive) |
|---|---|
| State | Not Applicable |
| Headers | show |
On Tue, Nov 01, 2016 at 10:06:18PM +0100, Jan Kara wrote: > Convert DAX faults to use iomap infrastructure. We would not have to start > transaction in ext4_dax_fault() anymore since ext4_iomap_begin takes > care of that but so far we do that to avoid lock inversion of > transaction start with DAX entry lock which gets acquired in > dax_iomap_fault() before calling ->iomap_begin handler. So far I've tried to avoid the need to avoid having multiple iomap_ops for the same fs. Would you be fine with a new IOMAP_FAULT flag for write faults?
On Wed 02-11-16 07:30:06, Christoph Hellwig wrote: > On Tue, Nov 01, 2016 at 10:06:18PM +0100, Jan Kara wrote: > > Convert DAX faults to use iomap infrastructure. We would not have to start > > transaction in ext4_dax_fault() anymore since ext4_iomap_begin takes > > care of that but so far we do that to avoid lock inversion of > > transaction start with DAX entry lock which gets acquired in > > dax_iomap_fault() before calling ->iomap_begin handler. > > So far I've tried to avoid the need to avoid having multiple iomap_ops > for the same fs. Would you be fine with a new IOMAP_FAULT flag for write > faults? Yes, that's another option. If that's better, I'll redo the patch like that. Honza
diff --git a/fs/ext4/ext4.h b/fs/ext4/ext4.h index 098b39910001..2714eb6174ab 100644 --- a/fs/ext4/ext4.h +++ b/fs/ext4/ext4.h @@ -3272,6 +3272,7 @@ static inline bool ext4_aligned_io(struct inode *inode, loff_t off, loff_t len) } extern struct iomap_ops ext4_iomap_ops; +extern struct iomap_ops ext4_iomap_fault_ops; #endif /* __KERNEL__ */ diff --git a/fs/ext4/file.c b/fs/ext4/file.c index d7ab0e90d1b8..da44e49c8276 100644 --- a/fs/ext4/file.c +++ b/fs/ext4/file.c @@ -273,7 +273,7 @@ static int ext4_dax_fault(struct vm_area_struct *vma, struct vm_fault *vmf) if (IS_ERR(handle)) result = VM_FAULT_SIGBUS; else - result = dax_fault(vma, vmf, ext4_dax_get_block); + result = dax_iomap_fault(vma, vmf, &ext4_iomap_fault_ops); if (write) { if (!IS_ERR(handle)) @@ -307,9 +307,10 @@ static int ext4_dax_pmd_fault(struct vm_area_struct *vma, unsigned long addr, if (IS_ERR(handle)) result = VM_FAULT_SIGBUS; - else - result = dax_pmd_fault(vma, addr, pmd, flags, - ext4_dax_get_block); + else { + result = dax_iomap_pmd_fault(vma, addr, pmd, flags, + &ext4_iomap_fault_ops); + } if (write) { if (!IS_ERR(handle)) diff --git a/fs/ext4/inode.c b/fs/ext4/inode.c index 635518dde20e..001fef06ea97 100644 --- a/fs/ext4/inode.c +++ b/fs/ext4/inode.c @@ -3419,11 +3419,29 @@ static int ext4_iomap_end(struct inode *inode, loff_t offset, loff_t length, return 0; } +/* + * For faults we don't allocate any blocks outside of isize and we don't want + * to change it so we use a dedicated function for it... + */ +static int ext4_iomap_fault_end(struct inode *inode, loff_t offset, + loff_t length, ssize_t written, unsigned flags, + struct iomap *iomap) +{ + if (flags & IOMAP_WRITE) + ext4_journal_stop(ext4_journal_current_handle()); + return 0; +} + struct iomap_ops ext4_iomap_ops = { .iomap_begin = ext4_iomap_begin, .iomap_end = ext4_iomap_end, }; +struct iomap_ops ext4_iomap_fault_ops = { + .iomap_begin = ext4_iomap_begin, + .iomap_end = ext4_iomap_fault_end, +}; + #else /* Just define empty function, it will never get called. */ int ext4_dax_get_block(struct inode *inode, sector_t iblock,
Convert DAX faults to use iomap infrastructure. We would not have to start transaction in ext4_dax_fault() anymore since ext4_iomap_begin takes care of that but so far we do that to avoid lock inversion of transaction start with DAX entry lock which gets acquired in dax_iomap_fault() before calling ->iomap_begin handler. Signed-off-by: Jan Kara <jack@suse.cz> --- fs/ext4/ext4.h | 1 + fs/ext4/file.c | 9 +++++---- fs/ext4/inode.c | 18 ++++++++++++++++++ 3 files changed, 24 insertions(+), 4 deletions(-)