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NTFS: - Modify ->readpage and ->writepage (fs/ntfs/aops.c) so they detect

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and handle the case where an attribute is converted from resident
        to non-resident by a concurrent file write.
      - Reorder some operations when converting an attribute from resident
        to non-resident (fs/ntfs/attrib.c) so it is safe wrt concurrent
        ->readpage and ->writepage.

Signed-off-by: Anton Altaparmakov <aia21@cantab.net>
This commit is contained in:
Anton Altaparmakov 2005-03-10 11:06:19 +00:00
parent 43b01fda8b
commit 905685f68f
3 changed files with 46 additions and 16 deletions
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3
fs/ntfs/ChangeLog
View file

@ -100,6 +100,9 @@ ToDo/Notes:
- Add fs/ntfs/attrib.[hc]::ntfs_attr_make_non_resident().
- Fix sign of various error return values to be negative in
fs/ntfs/lcnalloc.c.
- Modify ->readpage and ->writepage (fs/ntfs/aops.c) so they detect and
handle the case where an attribute is converted from resident to
non-resident by a concurrent file write.
2.1.22 - Many bug and race fixes and error handling improvements.

18
fs/ntfs/aops.c
View file

@ -355,6 +355,7 @@ static int ntfs_readpage(struct file *file, struct page *page)
u32 attr_len;
int err = 0;
retry_readpage:
BUG_ON(!PageLocked(page));
/*
* This can potentially happen because we clear PageUptodate() during
@ -408,6 +409,14 @@ static int ntfs_readpage(struct file *file, struct page *page)
err = PTR_ERR(mrec);
goto err_out;
}
/*
* If a parallel write made the attribute non-resident, drop the mft
* record and retry the readpage.
*/
if (unlikely(NInoNonResident(ni))) {
unmap_mft_record(base_ni);
goto retry_readpage;
}
ctx = ntfs_attr_get_search_ctx(base_ni, mrec);
if (unlikely(!ctx)) {
err = -ENOMEM;
@ -1248,6 +1257,7 @@ static int ntfs_writepage(struct page *page, struct writeback_control *wbc)
u32 attr_len;
int err;
retry_writepage:
BUG_ON(!PageLocked(page));
i_size = i_size_read(vi);
/* Is the page fully outside i_size? (truncate in progress) */
@ -1338,6 +1348,14 @@ static int ntfs_writepage(struct page *page, struct writeback_control *wbc)
ctx = NULL;
goto err_out;
}
/*
* If a parallel write made the attribute non-resident, drop the mft
* record and retry the writepage.
*/
if (unlikely(NInoNonResident(ni))) {
unmap_mft_record(base_ni);
goto retry_writepage;
}
ctx = ntfs_attr_get_search_ctx(base_ni, m);
if (unlikely(!ctx)) {
err = -ENOMEM;

41
fs/ntfs/attrib.c
View file

@ -1376,19 +1376,6 @@ int ntfs_attr_make_non_resident(ntfs_inode *ni)
err = ntfs_attr_record_resize(m, a, arec_size);
if (unlikely(err))
goto err_out;
/* Setup the in-memory attribute structure to be non-resident. */
NInoSetNonResident(ni);
ni->runlist.rl = rl;
write_lock_irqsave(&ni->size_lock, flags);
ni->allocated_size = new_size;
write_unlock_irqrestore(&ni->size_lock, flags);
/*
* FIXME: For now just clear all of these as we do not support them
* when writing.
*/
NInoClearCompressed(ni);
NInoClearSparse(ni);
NInoClearEncrypted(ni);
/*
* Convert the resident part of the attribute record to describe a
* non-resident attribute.
@ -1399,7 +1386,10 @@ int ntfs_attr_make_non_resident(ntfs_inode *ni)
memmove((u8*)a + name_ofs, (u8*)a + le16_to_cpu(a->name_offset),
a->name_length * sizeof(ntfschar));
a->name_offset = cpu_to_le16(name_ofs);
/* Update the flags to match the in-memory ones. */
/*
* FIXME: For now just clear all of these as we do not support them
* when writing.
*/
a->flags &= cpu_to_le16(0xffff & ~le16_to_cpu(ATTR_IS_SPARSE |
ATTR_IS_ENCRYPTED | ATTR_COMPRESSION_MASK));
/* Setup the fields specific to non-resident attributes. */
@ -1422,6 +1412,25 @@ int ntfs_attr_make_non_resident(ntfs_inode *ni)
err);
goto undo_err_out;
}
/* Setup the in-memory attribute structure to be non-resident. */
/*
* FIXME: For now just clear all of these as we do not support them
* when writing.
*/
NInoClearSparse(ni);
NInoClearEncrypted(ni);
NInoClearCompressed(ni);
ni->runlist.rl = rl;
write_lock_irqsave(&ni->size_lock, flags);
ni->allocated_size = new_size;
write_unlock_irqrestore(&ni->size_lock, flags);
/*
* This needs to be last since the address space operations ->readpage
* and ->writepage can run concurrently with us as they are not
* serialized on i_sem. Note, we are not allowed to fail once we flip
* this switch, which is another reason to do this last.
*/
NInoSetNonResident(ni);
/* Mark the mft record dirty, so it gets written back. */
flush_dcache_mft_record_page(ctx->ntfs_ino);
mark_mft_record_dirty(ctx->ntfs_ino);
@ -1431,6 +1440,7 @@ int ntfs_attr_make_non_resident(ntfs_inode *ni)
if (page) {
set_page_dirty(page);
unlock_page(page);
mark_page_accessed(page);
page_cache_release(page);
}
ntfs_debug("Done.");
@ -1492,11 +1502,10 @@ undo_err_out:
memcpy((u8*)a + mp_ofs, kaddr, attr_size);
kunmap_atomic(kaddr, KM_USER0);
}
/* Finally setup the ntfs inode appropriately. */
/* Setup the allocated size in the ntfs inode in case it changed. */
write_lock_irqsave(&ni->size_lock, flags);
ni->allocated_size = arec_size - mp_ofs;
write_unlock_irqrestore(&ni->size_lock, flags);
NInoClearNonResident(ni);
/* Mark the mft record dirty, so it gets written back. */
flush_dcache_mft_record_page(ctx->ntfs_ino);
mark_mft_record_dirty(ctx->ntfs_ino);