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cifs: define variable sized buffer for querydir responses

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QueryDirectory responses today are stored in one of two fixed
sized buffers: smallbuf (448 bytes) or bigbuf (16KB). These are
borrowed from server struct and are not sufficient for large-sized
query dir operations.

With this change we will now define a new buffer type specifically
for cifs_search_info to hold variable sized responses. These will
be allocated by kmalloc and freed by kfree.

Signed-off-by: Shyam Prasad N <sprasad@microsoft.com>
Signed-off-by: Steve French <stfrench@microsoft.com>
This commit is contained in:
Shyam Prasad N 2026-03-10 16:00:17 +05:30 committed by Steve French
parent 99cd0a6eeb
commit f53208233b
4 changed files with 17 additions and 3 deletions
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2
fs/smb/client/cifsglob.h
View File

@ -1393,6 +1393,7 @@ struct cifs_search_info {
bool emptyDir:1;
bool unicode:1;
bool smallBuf:1; /* so we know which buf_release function to call */
bool is_dynamic_buf:1; /* dynamically allocated buffer - can be variable size */
};
#define ACL_NO_MODE ((umode_t)(-1))
@ -1906,6 +1907,7 @@ enum cifs_find_flags {
#define CIFS_NO_BUFFER 0 /* Response buffer not returned */
#define CIFS_SMALL_BUFFER 1
#define CIFS_LARGE_BUFFER 2
#define CIFS_DYNAMIC_BUFFER 3 /* Dynamically allocated buffer */
#define CIFS_IOVEC 4 /* array of response buffers */
/* Type of Request to SendReceive2 */

2
fs/smb/client/file.c
View File

@ -1563,6 +1563,8 @@ int cifs_closedir(struct inode *inode, struct file *file)
cfile->srch_inf.ntwrk_buf_start = NULL;
if (cfile->srch_inf.smallBuf)
cifs_small_buf_release(buf);
else if (cfile->srch_inf.is_dynamic_buf)
kfree(buf);
else
cifs_buf_release(buf);
}

2
fs/smb/client/readdir.c
View File

@ -732,6 +732,8 @@ find_cifs_entry(const unsigned int xid, struct cifs_tcon *tcon, loff_t pos,
if (cfile->srch_inf.smallBuf)
cifs_small_buf_release(cfile->srch_inf.
ntwrk_buf_start);
else if (cfile->srch_inf.is_dynamic_buf)
kfree(cfile->srch_inf.ntwrk_buf_start);
else
cifs_buf_release(cfile->srch_inf.
ntwrk_buf_start);

14
fs/smb/client/smb2pdu.c
View File

@ -5673,6 +5673,8 @@ smb2_parse_query_directory(struct cifs_tcon *tcon,
if (srch_inf->ntwrk_buf_start) {
if (srch_inf->smallBuf)
cifs_small_buf_release(srch_inf->ntwrk_buf_start);
else if (srch_inf->is_dynamic_buf)
kfree(srch_inf->ntwrk_buf_start);
else
cifs_buf_release(srch_inf->ntwrk_buf_start);
}
@ -5692,12 +5694,18 @@ smb2_parse_query_directory(struct cifs_tcon *tcon,
cifs_dbg(FYI, "num entries %d last_index %lld srch start %p srch end %p\n",
srch_inf->entries_in_buffer, srch_inf->index_of_last_entry,
srch_inf->srch_entries_start, srch_inf->last_entry);
if (resp_buftype == CIFS_LARGE_BUFFER)
if (resp_buftype == CIFS_LARGE_BUFFER) {
srch_inf->smallBuf = false;
else if (resp_buftype == CIFS_SMALL_BUFFER)
srch_inf->is_dynamic_buf = false;
} else if (resp_buftype == CIFS_SMALL_BUFFER) {
srch_inf->smallBuf = true;
else
srch_inf->is_dynamic_buf = false;
} else if (resp_buftype == CIFS_DYNAMIC_BUFFER) {
srch_inf->smallBuf = false;
srch_inf->is_dynamic_buf = true;
} else {
cifs_tcon_dbg(VFS, "Invalid search buffer type\n");
}
return 0;
}